Footnotes:[1]A short account of this discovery has been given in Dr. Beddoes’s Notice of some Observations made at the Pneumatic Institution, and in Mr. Nicholson’s Phil. Journal for May and December 1799.[2]Cavendish, Priestley, Black, Lavoisier, Scheele, Kirwan, Guyton, Berthollet, &c.[3]Phil. Trans. v. 78, p. 270.[4]Phil. Trans. v. 75 p. 381.[5]Elem. Kerr’s Trans. page 76, and 216, and Mem. des Sav. Etrang. tom. 7, page 629.[6]Ingenhouz sur les Vegetaux, pag. 205. De la Metherie. Essai sur differens Airs, pag. 252.[7]Annales de Chimie, tome 28, p. 168.[8]Experiments and Observations, Vol. iii. last edition, page 105, &c.[9]When copper is dissolved in dilute nitrous acid, certain quantities of nitrogene are generally produced, likewise the nitrous gas carries off in solution some nitrous acid.[10]This airholder, considered as a pneumatic instrument, is of greater importance, and capable of a more extensive application than any other. It was invented by Mr.W. Clayfield, and in its form is analogous to Mr.Watt’shydraulic bellows, consisting of a glass bell playing under the pressure of the atmosphere, in a space between two cylinders filled with mercury. A particular account of it will be given in theappendix.[11]This absorption will be hereafter particularly treated of.[12]Annales de Chimie. Tome xviii. page 139.[13]A table of the specific gravities of these gases, and other gases, hereafter to be mentioned, reduced to a barometrical and thermometrical standard, will be given in theappendix.[14]40 measures, exposed to solution of potash, gave an absorption of not quite a quarter of a measure: hence it contained an inconsiderable quantity of carbonic acid.[15]Traité Elementaire.[16]Essai sur le phlogistique, page 30.[17]The diminution of the specific gravity of the gas from the quantity of nitrogene evolved in his experiment, probably destroyed, in some measure, the source of error from the nitrous acid carried over.[18]Experiment I.[19]That no greater contraction took place depended on the solution of the nitrous acid formed in the nitrous gas; a phænomenon to be explained hereafter.[20]I judged it expedient always to ascertain the quantity of air in the stop-cocks by weight, as it was impossible to join them so as to have always an equal capacity. The upper tubes of the two stop-cocks not joined, contained nearly an inch and half.[21]That is, by the solution of ammonia, and air.[22]The following is an account of the increase and diminution of weight of the globe, as it was noted in the journal.Globe filled with common airgr. 2066,5After exhaustion2034,5After introduction of nitrous gas, 82 cubic inches2064,25After the accidental admission of common air2067,25After the admission of oxygene2091,75—— —— 41 grains of water2133,25—— —— 51 cubic inches of air2149,75Taken out 54 grains of solution2095,75Introduced 13 grains of ammoniacal solution2109,25After introduction of common air2106,5[23]Decimals are omitted, because the excess of the two first numbers is exactly corrected by the deficiency of the last.[24]As is evident from the superabundant quantity of oxygene thrown into the globe.[25]The weight of the acid poured into the cylinder being known, its specific gravity was known from the space it occupied in the phial. The weight of water being likewise known, the specific gravity of the solution, when the common temperature was produced, was given by the condensation.[26]That is, such as it exists in the aëriform state at 55°. From the strong affinity of nitrous acid for water, we may suppose that this acid gas contains a larger proportion of it than the other gases.[27]This appearance will be explained hereafter.[28]This phænomenon will be particularly explained hereafter.[29]The outline only of this apparatus is given here, as far as was necessary to make the experiment intelligible; a detailed account of it, and of its general application, will be given in theappendix.[30]That is, from nitrous acid and mercury.[31]A pale acid of 1.52, by being converted into yellow acid, became nearly of specific gravity 15,1.[32]It is impossible to ascertain the quantity of gas absorbed to more than a quarter of a cubic inch, as the first portions of nitrous gas thrown into the graduated cylinder are combined with the oxygene of the common air in it, to form nitrous acid, and hence the slight excess of weight.[33]In a letter to me, dated Oct. 28, 1799, after giving an account of some experiments on the phlogistication of nitric acid by heat and light, he says, “It was from an attentive examination of the manner in which the nitric acid was phlogisticated in these experiments, that I was confirmed in the suspicion I had long before entertained, of the real difference between thenitrousandnitricacids. It is not enough to shew that in thenitrousacid, (that is, the nitric holding nitrous gas in solution), the proportion of oxygene in the whole compound is less than that entering into the composition of the nitric acid, and that it is therefore less oxygenated. By the same mode of reasoning we might prove that water, by absorbing carbonic acid gas, became less oxygenated, which is absurd. Should any one attempt to prove (which will be necessary to substantiate the generally received doctrine) that the oxygene of the nitrous gas combines with the oxygene of the acid, and the nitrogene, in like manner, so that the resulting acid, when nitrous gas is absorbed by nitric acid, is a binary combination of oxygene and nitrogene, he would find it somewhat more difficult than he at first imagined; it appears to me impossible. It is much more consonant with experiment to suppose that nitrous acid is nothing more than nitric acid holding nitrous gas in solution, which might in conformity to the principles of the French nomenclature, be called nitrate of nitrogene. The difficulty, and in some cases the impossibility, of forming nitrites, arises from the weak affinity which nitrous gas has for nitric acid, compared with that of other substances; and the decomposition of nitrous acid (that is, nitrate of nitrogene) by an alkaline or metallic substance, is perfectly analogous to the decomposition of any other nitrate, the nitrous gas being displaced by the superior affinity of the alkali for the acid.“Agreeable to this theory, the salts denominatednitritesare in fact triple salts, or ternary combinations of nitric acid, nitrous gas, and salifiable bases.”This theory is perfectly new to me. Other Chemists to whom I have mentioned it, have likewise considered it as new. Yet in a subsequent letter Mr. Thomson mentions that he had been told of the belief of a similar opinion among the French Chemists.[34]In some experiments made on the nitrites of potash, and of ammoniac, before I was well acquainted with the composition of nitric acid, I found that a light olive-colored acid of 1,28, was capable of being saturated by weak solutions of potash and ammoniac, without losing any nitrous gas; but after the evaporation of the neutralised solution, at very low temperatures, the salts in all their properties resemblednitrates.[35]As is evident from the curious appearance of the dark green spherules, repulsive both to water, and light green acid.[36]That is, undecompounded.[37]The existence of these bodies will be hereafter proved.[38]The blue green acid is not homogeneal in its composition, it is composed of the blue green spherules and the bright green acid. The blue green spherules are of greater specific gravity than the dark green acid, probably because they contain little or no water.[39]The composition of the acids thus marked, is given from calculations.[40]Nitrous gas contains 44,05 Nitrogene, and 55,95 Oxygene, as has been said before.[41]A great portion of it, of course, dissolved in the water with the nitrous acid carried over.[42]Their changes of volume, corresponding to changes of temperature, most probably, are likewise different.[43]Probably in the ratio of the square of the quantity of water united to it.[44]The quantities of Oxygene and Nitrogene in any solution, may be thus found—— Let A = the true acid, X the oxygene, and Y the nitrogene.Then238 AAX =———and Y =———239239[45]Experiments and Observations; last edition, vol. 1, page 384.[46]Nitrous gas, holding in solution nitrous acid, is more readily absorbed by water than when in its pure form, from being presented to it in a more condensed state in the green acid, formed by the contact of water and nitrous vapor.[47]Mem. des Savans Etrangers, v. xi. 226. Vide Kirwan sur le phlogistique pag. 110.[48]In this experiment, as well as in the last, some of the mixture was thrown into the jar undecompounded.[49]To detach the potash from the carbonic acid.[50]This nitrogene contained a little nitrous gas, as it gave red fumes when exposed to the air. The free nitrous acid was decomposed by the mercury, as it was not covered with water.[51]Essay on phlogiston.[52]Dr. Priestley says, “Having filled a phial containing exactly the quantity of four pennyweights of water, with strong, pale, yellow spirit of nitre, with its mouth quite close to the top of a large receiver standing in water, I carefully drew out almost all the common air, and then filled it with nitrous air; and as this was absorbed, I kept putting in more and more, till in less than two days it had completely absorbed 130 ounce measures. Presently after this process began, the surface of the acid assumed a deep orange color, and when 20 or 30 ounce measures of air were absorbed, it became green at the top: this green descended lower and lower, till it reached the bottom of the phial. Towards the end of the process, the evaporation was perceived to be very great, and when I took it out, the quantity was found to have diminished to one half. Also it had become, by means of this process, and the evaporation together, exceeding weak, and was rather blue than green.”Experiments and Observations, vol. 1, p. 384. Last edition.[53]See Mr. Keir’s excellent observations on this subject. Chem. Dict. Art. Acid.[54]Irish Transactions, vol. 4, p. 34.[55]Addit. Obs. pag. 74.[56]Additional Observations, page 70.[57]Elements, pag. 103, Kerr’s Translation.[58]Mem. Acad. 1787.[59]As well as oxygene and nitrogene, Mr. Watt’s experiments prove that much phlogisticated nitrous acid is produced.[60]Journal de Physique, 1786. Tom. 2, pag. 176.[61]Though the tube had never been used, and was apparently clean and dry on the inside, it must have contained something in the form of dust, capable of furnishing either hydrocarbonate, or charcoal.[62]Journal de Physique, 1786, t. 2, 177.[63]Phil. Trans. vol. 79, page 294.[64]Vol. 2, page 398.[65]Ammoniac generated at a temperature above that of the atmosphere, always deposits ammoniacal solution during its reduction to the common temperature.[66]By the introduction of aëriform ammoniac into the exhausted globe.[67]Additional Observations, page 107.[68]It is necessary in these experiments, that the greatest care be observed in the introduction and extraction of the capillary tube. If it is introduced dry, there will be a source of error from the moisture adhering to it when taken out. I therefore always wetted it before its introduction, and took care that no more fluid adhered to it after the experiment, than before.[69]Previous to those experiments, I had made a number of others on the combination of ammoniac with water.—My design was, to ascertain the diminution of specific gravity for every three grains of ammoniac absorbed; but this I found impossible. The capillary tube, when taken out of the phial, always carried with it a minute portion of the solution, which partially evaporated before it could be again introduced; and thus the sources of error increased in proportion to the number of examinations.[70]The expansion from increase of temperature is probably great in proportion to the quantity of ammoniac in the solution.[71]From the combination.[72]I had before proved that at this temperature the salt neither decomposed nor sublimed.[73]A particular account of the experiments from which these facts were deduced, was printed in September, and will appear in the first volume of theResearches.[74]And which will be published, with an account of its perfect decomposition at a high temperature, in theResearches.[75]When nitrous gas exists in neutro-saline solutions, they are always colored more or less intensely, from yellow to olive, in proportion to the quantity combined with them.[76]Hence a nitrate of ammoniac with excess of acid, when exposed to heat, first becomes yellow, and then white.[77]The accounts given by different chemists of the composition of nitrate of ammoniac, are extremely discordant; they have been chiefly deduced from decompositions of carbonate of ammoniac (the varieties of which have been heretofore unknown) by nitrous acids of unknown degrees of nitration. Hence they are particularly erroneous with regard to the alkaline part. Wenzel supposes it to be 32 per cent, and Kirwan 24.Addit. Observ.pag. 120.[78]Mem. Par. 1783. See Irish Trans. vol. 4.[79]Addit. Obs. pag. 120.[80]Two measures of air dispelled from this water by boiling, mingled with 2 of nitrous gas, diminished to 2,4 nearly.[81]Experiments and Observations, vol. 2, pag. 89. Last Edition.[82]A minute quantity, however, must have been absorbed, and given out again when the charcoal was heated.[83]Strong solution of ammoniac has no attraction for nitrous oxide.[84]The gas was examined by those tests in order to prove that no water had been decomposed.[85]See the curious paper of this excellent philosopher, on the combustion of the diamond, in which he proves that charcoal is, in fact, oxide of diamond. Annales de Chimie, xxxi.[86]This was actually the case; for on examining the conducting tube the day after the experiment, some minute crystals of prismatic nitrate of ammoniac were perceived in it.[87]Owing part of their weight to an unknown quantity of water.[88]Mem. de Paris. 1785, and Journal de Physique, 1786, page 175.[89]The absorption of nitrous gas by sulphate of iron, &c. will be treated of in the next division.[90]As is evident from the decomposition of ammoniac by heat.[91]Nitric acid is phlogisticated by heat, as appears from Dr. Priestley’s experiments. Vol. 3, p. 26.[92]As is evident from the increase of temperature required for the formation of water.[93]For ammoniac and nitrous oxide are both decomposed at the red heat, and oxygene given out from nitric acid when it is passed through a heated tube.[94]Whenever nitrous acid is produced at high temperatures, it is always highly phlogisticated, provided it has not been long in contact with oxygene. When Dr. Priestley passed nitric acid through a tube heated red, he procured much oxygene, and phlogisticated acid; and the water in the apparatus employed was fully impregnated with nitrous air. Hence it would appear, that heat diminishes the attraction between oxygene and nitrous gas, and increases the affinity of nitrous gas for nitrous acid. Mr.James Thomson, whose theory of the Nitrous Acid I have already mentioned, from some experiments on the phlogistication of Nitric Acid by heat, which he has communicated to me, concludes with great justness, that a portion of the acid is always completely decomposed in this process: the oxygene liberated, and the nitrous gas combined with the remaining acid.[95]Except it be gold or platina.[96]A pound of nitrate of ammoniac costs about 5s. 10d. This pound, properly decomposed, produces rather more than 34 moderate doses of air; so that the expence of a dose is about 2d. What fluid stimulus can be procured at so cheap a rate?[97]Experiments and Observations, vol. II. pag. 50. Last Edition.[98]That is, charcoal produced by the decomposition of spirits of wine. Vol. II. pag. 39.[99]Dr. Priestley says, “having heated iron in nitrous air, I proceeded to heat in the same air, a piece of charcoal not long after it had been subjected to a strong heat covered with sand. The sun not shining immediately, after the charcoal was introduced into the vessel of air, through the mercury by which it was confined, part of the air was absorbed; but on heating the charcoal, the quantity was increased. Having continued the progress as long as I thought necessary, I examined the air and found it to be about as much as the original quantity of nitrous air; but it was all phlogisticated air extinguishing a candle and having no mixture of fixed air in it.”—Experiments and Observations, Vol. II, page 39.[100]That is, sulphate of iron containing oxide of iron, in the first degree of oxygenation.[101]That is, carbon, or oxide of diamond.[102]That is, blue prussiate of iron.[103]No luminous appearance is produced when phosphorus is introduced intopurenitrous gas. It has been often observed, that phosphorus is luminous in nitrous gas, that has not been long in contact with water after its production. This phænomenon, I suspect, depends either on the decomposition of the nitric acid held in solution by the nitrous gas; or on the combination of the phosphorus with oxygene loosely adhering to the binary aëriform compound of nitric acid and nitrous gas. I have not yet examined if nitrous gas can be converted into nitrous oxide by long exposure to heated phosphorus: it appears, however, very probable.[104]Perhaps this fact has been noticed before; I have not, however, met with it in any chemical work.[105]This mode of inflaming bodies in gases, not capable of supporting combustion at low temperatures, will be particularly described hereafter.[106]Elements English Trans. edit. i. pag. 216.[107]Experiments and Observations, Vol. II. pag. 40, 2d. Ed.[108]He says, “On a observé, (depuis qu’on travaille sur le pureté de l’air) que le gaz nitreux, secoué avec l’eau, en souffre une diminution de volume. Quelques physiciens attribuent ce changement à une vraie absorption, à une dissolution du gaz nitreux dans l’eau; d’autres à l’air contenu dans les interstices de tous les fluides. Le cit. Vanbreda, à Delft, a fait des recherches très-exactes sur l’influence des eaux de pluie et de puit, sur les nombres eudiométriques; et les belles expériences du cit. Hassenfratz, sur l’abondance d’oxygène, contenue dans les eaux de neige et de pluie, sont supposer que l’air des interstices de l’eau joue un rôle important dans l’absorption du gaz nitreux. En comparant ces effets avec les phénomènes observé dans la decomposition du sulfate de fer, nous supposâmes, le cit. Tassaert et moi, que le simple contact du gaz nitreux avec l’eau distillée pourroit bien causer une décomposition de ce dernier. Nous examinâmes soigneusement une petite quantité d’eau distillée, secouée avec beaucoup de gas nitreux trés-pur, et nous trouvâmes, au moyen de la terre calcaire, et l’acide muriatique, qu’il s’y forme dunitrate d’ammoniaque. L’eau se décompose en cette opération, par un double affinité de l’oxygene pour le gaz nitreux, et de l’hydrogène pour l’azote; il se forme de l’acide nitrique et de l’ammoniaque; et, quoique la quantité du dernier paroisse trop petite pour en évaluer exactment la quantité, son existence cependant se manifeste, (à ne pas sans douter) par le dégagement des vapeurs, qui blanchissent dans la proximité de l’acide muriatique. Voilá un fait bien frappant que la composition d’une substance alcaline par le contact d’une acide, et de l’eau.”Annales de Chimie, t. xxviii. pag. 153.[109]Which was certainly as free from air as it ever can be obtained.[110]Dr. Priestley found distilled water, saturated with nitrous air, to acquire an astringent taste and pungent smell. In some unboiled impregnated pump water, I once thought that I perceived a subacid taste; but it was extremely slight, and probably owing to nitrous acid formed by the union of the oxygene of the common air in the water, with some of the nitrous gas.[111]As carbonic acid and ammoniac are both products of animalisation, is it not probable that our common waters particularly those in, and near towns and cities, contain carbonate of ammoniac? If so, this salt will always exist in them after distillation. In the experiments on carbonate of ammoniac, to which I have often alluded, I found, in distilling a solution of this salt in water, that before half of the water had passed into the recipient, the carbonate of ammoniac had sublimed; so that the distilled solution was much stronger than before, whilst the water remaining in the retort was tasteless. Will this supposition at all explain Humbolt’s mistake?[112]The water still being unity.[113]He says “100 parties de gaz nitreux, (à 0.14 d’azote) secouées avec l’eau distillée, récemment cuite, diminuent en volume de 0.11, ou 0.12. Ce même gaz, en contact avec l’eau de puits, ne perd que 0.02. La cause de cette différence de 0.9, ou 0.10, ne doit pas être attribuée ni à l’impurité de l’air atmosphérique, contenu dans les interstices de l’eau, ni à la décomposition de cette eau même. Elle n’est qu’apparente; car l’acide nitrique, qui se forme par le contact du gaz nitreux avec l’eau de puits, en décompose le carbonate de chaux. Il se dégage de l’acide carbonique, qui, en augmentant le volume du residu, rend l’absorption du gaz nitreux moins sensible. Pour déterminer la quantité de cet acide carbonique, je lavai le résidu avec de l’eau de chaux. Dans un grand nombre d’expériences, le volume diminua de 0.09, ou 0.07. Il faut en conduire que l’eau de puits absorbe réellement 9 + 2, ou 7 + 2 parties de gas nitreux, c’est-à-dire, à peu-près la même quantité que l’eau distillée.”Annales De Chimie, xxviii. pag. 154.[114]Nicholson’s Phil. Jour. No. 1, p. 453.[115]I have been able to make these observations on the sulphates of iron, most of them after Proust.[116]Annales de Chimie, vol. xxviii. pag. 182.[117]Division IV. Section 5.[118]Division II. Section 1.
Footnotes:
[1]A short account of this discovery has been given in Dr. Beddoes’s Notice of some Observations made at the Pneumatic Institution, and in Mr. Nicholson’s Phil. Journal for May and December 1799.
[1]A short account of this discovery has been given in Dr. Beddoes’s Notice of some Observations made at the Pneumatic Institution, and in Mr. Nicholson’s Phil. Journal for May and December 1799.
[2]Cavendish, Priestley, Black, Lavoisier, Scheele, Kirwan, Guyton, Berthollet, &c.
[2]Cavendish, Priestley, Black, Lavoisier, Scheele, Kirwan, Guyton, Berthollet, &c.
[3]Phil. Trans. v. 78, p. 270.
[3]Phil. Trans. v. 78, p. 270.
[4]Phil. Trans. v. 75 p. 381.
[4]Phil. Trans. v. 75 p. 381.
[5]Elem. Kerr’s Trans. page 76, and 216, and Mem. des Sav. Etrang. tom. 7, page 629.
[5]Elem. Kerr’s Trans. page 76, and 216, and Mem. des Sav. Etrang. tom. 7, page 629.
[6]Ingenhouz sur les Vegetaux, pag. 205. De la Metherie. Essai sur differens Airs, pag. 252.
[6]Ingenhouz sur les Vegetaux, pag. 205. De la Metherie. Essai sur differens Airs, pag. 252.
[7]Annales de Chimie, tome 28, p. 168.
[7]Annales de Chimie, tome 28, p. 168.
[8]Experiments and Observations, Vol. iii. last edition, page 105, &c.
[8]Experiments and Observations, Vol. iii. last edition, page 105, &c.
[9]When copper is dissolved in dilute nitrous acid, certain quantities of nitrogene are generally produced, likewise the nitrous gas carries off in solution some nitrous acid.
[9]When copper is dissolved in dilute nitrous acid, certain quantities of nitrogene are generally produced, likewise the nitrous gas carries off in solution some nitrous acid.
[10]This airholder, considered as a pneumatic instrument, is of greater importance, and capable of a more extensive application than any other. It was invented by Mr.W. Clayfield, and in its form is analogous to Mr.Watt’shydraulic bellows, consisting of a glass bell playing under the pressure of the atmosphere, in a space between two cylinders filled with mercury. A particular account of it will be given in theappendix.
[10]This airholder, considered as a pneumatic instrument, is of greater importance, and capable of a more extensive application than any other. It was invented by Mr.W. Clayfield, and in its form is analogous to Mr.Watt’shydraulic bellows, consisting of a glass bell playing under the pressure of the atmosphere, in a space between two cylinders filled with mercury. A particular account of it will be given in theappendix.
[11]This absorption will be hereafter particularly treated of.
[11]This absorption will be hereafter particularly treated of.
[12]Annales de Chimie. Tome xviii. page 139.
[12]Annales de Chimie. Tome xviii. page 139.
[13]A table of the specific gravities of these gases, and other gases, hereafter to be mentioned, reduced to a barometrical and thermometrical standard, will be given in theappendix.
[13]A table of the specific gravities of these gases, and other gases, hereafter to be mentioned, reduced to a barometrical and thermometrical standard, will be given in theappendix.
[14]40 measures, exposed to solution of potash, gave an absorption of not quite a quarter of a measure: hence it contained an inconsiderable quantity of carbonic acid.
[14]40 measures, exposed to solution of potash, gave an absorption of not quite a quarter of a measure: hence it contained an inconsiderable quantity of carbonic acid.
[15]Traité Elementaire.
[15]Traité Elementaire.
[16]Essai sur le phlogistique, page 30.
[16]Essai sur le phlogistique, page 30.
[17]The diminution of the specific gravity of the gas from the quantity of nitrogene evolved in his experiment, probably destroyed, in some measure, the source of error from the nitrous acid carried over.
[17]The diminution of the specific gravity of the gas from the quantity of nitrogene evolved in his experiment, probably destroyed, in some measure, the source of error from the nitrous acid carried over.
[18]Experiment I.
[18]Experiment I.
[19]That no greater contraction took place depended on the solution of the nitrous acid formed in the nitrous gas; a phænomenon to be explained hereafter.
[19]That no greater contraction took place depended on the solution of the nitrous acid formed in the nitrous gas; a phænomenon to be explained hereafter.
[20]I judged it expedient always to ascertain the quantity of air in the stop-cocks by weight, as it was impossible to join them so as to have always an equal capacity. The upper tubes of the two stop-cocks not joined, contained nearly an inch and half.
[20]I judged it expedient always to ascertain the quantity of air in the stop-cocks by weight, as it was impossible to join them so as to have always an equal capacity. The upper tubes of the two stop-cocks not joined, contained nearly an inch and half.
[21]That is, by the solution of ammonia, and air.
[21]That is, by the solution of ammonia, and air.
[22]The following is an account of the increase and diminution of weight of the globe, as it was noted in the journal.Globe filled with common airgr. 2066,5After exhaustion2034,5After introduction of nitrous gas, 82 cubic inches2064,25After the accidental admission of common air2067,25After the admission of oxygene2091,75—— —— 41 grains of water2133,25—— —— 51 cubic inches of air2149,75Taken out 54 grains of solution2095,75Introduced 13 grains of ammoniacal solution2109,25After introduction of common air2106,5
[22]The following is an account of the increase and diminution of weight of the globe, as it was noted in the journal.
[23]Decimals are omitted, because the excess of the two first numbers is exactly corrected by the deficiency of the last.
[23]Decimals are omitted, because the excess of the two first numbers is exactly corrected by the deficiency of the last.
[24]As is evident from the superabundant quantity of oxygene thrown into the globe.
[24]As is evident from the superabundant quantity of oxygene thrown into the globe.
[25]The weight of the acid poured into the cylinder being known, its specific gravity was known from the space it occupied in the phial. The weight of water being likewise known, the specific gravity of the solution, when the common temperature was produced, was given by the condensation.
[25]The weight of the acid poured into the cylinder being known, its specific gravity was known from the space it occupied in the phial. The weight of water being likewise known, the specific gravity of the solution, when the common temperature was produced, was given by the condensation.
[26]That is, such as it exists in the aëriform state at 55°. From the strong affinity of nitrous acid for water, we may suppose that this acid gas contains a larger proportion of it than the other gases.
[26]That is, such as it exists in the aëriform state at 55°. From the strong affinity of nitrous acid for water, we may suppose that this acid gas contains a larger proportion of it than the other gases.
[27]This appearance will be explained hereafter.
[27]This appearance will be explained hereafter.
[28]This phænomenon will be particularly explained hereafter.
[28]This phænomenon will be particularly explained hereafter.
[29]The outline only of this apparatus is given here, as far as was necessary to make the experiment intelligible; a detailed account of it, and of its general application, will be given in theappendix.
[29]The outline only of this apparatus is given here, as far as was necessary to make the experiment intelligible; a detailed account of it, and of its general application, will be given in theappendix.
[30]That is, from nitrous acid and mercury.
[30]That is, from nitrous acid and mercury.
[31]A pale acid of 1.52, by being converted into yellow acid, became nearly of specific gravity 15,1.
[31]A pale acid of 1.52, by being converted into yellow acid, became nearly of specific gravity 15,1.
[32]It is impossible to ascertain the quantity of gas absorbed to more than a quarter of a cubic inch, as the first portions of nitrous gas thrown into the graduated cylinder are combined with the oxygene of the common air in it, to form nitrous acid, and hence the slight excess of weight.
[32]It is impossible to ascertain the quantity of gas absorbed to more than a quarter of a cubic inch, as the first portions of nitrous gas thrown into the graduated cylinder are combined with the oxygene of the common air in it, to form nitrous acid, and hence the slight excess of weight.
[33]In a letter to me, dated Oct. 28, 1799, after giving an account of some experiments on the phlogistication of nitric acid by heat and light, he says, “It was from an attentive examination of the manner in which the nitric acid was phlogisticated in these experiments, that I was confirmed in the suspicion I had long before entertained, of the real difference between thenitrousandnitricacids. It is not enough to shew that in thenitrousacid, (that is, the nitric holding nitrous gas in solution), the proportion of oxygene in the whole compound is less than that entering into the composition of the nitric acid, and that it is therefore less oxygenated. By the same mode of reasoning we might prove that water, by absorbing carbonic acid gas, became less oxygenated, which is absurd. Should any one attempt to prove (which will be necessary to substantiate the generally received doctrine) that the oxygene of the nitrous gas combines with the oxygene of the acid, and the nitrogene, in like manner, so that the resulting acid, when nitrous gas is absorbed by nitric acid, is a binary combination of oxygene and nitrogene, he would find it somewhat more difficult than he at first imagined; it appears to me impossible. It is much more consonant with experiment to suppose that nitrous acid is nothing more than nitric acid holding nitrous gas in solution, which might in conformity to the principles of the French nomenclature, be called nitrate of nitrogene. The difficulty, and in some cases the impossibility, of forming nitrites, arises from the weak affinity which nitrous gas has for nitric acid, compared with that of other substances; and the decomposition of nitrous acid (that is, nitrate of nitrogene) by an alkaline or metallic substance, is perfectly analogous to the decomposition of any other nitrate, the nitrous gas being displaced by the superior affinity of the alkali for the acid.“Agreeable to this theory, the salts denominatednitritesare in fact triple salts, or ternary combinations of nitric acid, nitrous gas, and salifiable bases.”This theory is perfectly new to me. Other Chemists to whom I have mentioned it, have likewise considered it as new. Yet in a subsequent letter Mr. Thomson mentions that he had been told of the belief of a similar opinion among the French Chemists.
[33]In a letter to me, dated Oct. 28, 1799, after giving an account of some experiments on the phlogistication of nitric acid by heat and light, he says, “It was from an attentive examination of the manner in which the nitric acid was phlogisticated in these experiments, that I was confirmed in the suspicion I had long before entertained, of the real difference between thenitrousandnitricacids. It is not enough to shew that in thenitrousacid, (that is, the nitric holding nitrous gas in solution), the proportion of oxygene in the whole compound is less than that entering into the composition of the nitric acid, and that it is therefore less oxygenated. By the same mode of reasoning we might prove that water, by absorbing carbonic acid gas, became less oxygenated, which is absurd. Should any one attempt to prove (which will be necessary to substantiate the generally received doctrine) that the oxygene of the nitrous gas combines with the oxygene of the acid, and the nitrogene, in like manner, so that the resulting acid, when nitrous gas is absorbed by nitric acid, is a binary combination of oxygene and nitrogene, he would find it somewhat more difficult than he at first imagined; it appears to me impossible. It is much more consonant with experiment to suppose that nitrous acid is nothing more than nitric acid holding nitrous gas in solution, which might in conformity to the principles of the French nomenclature, be called nitrate of nitrogene. The difficulty, and in some cases the impossibility, of forming nitrites, arises from the weak affinity which nitrous gas has for nitric acid, compared with that of other substances; and the decomposition of nitrous acid (that is, nitrate of nitrogene) by an alkaline or metallic substance, is perfectly analogous to the decomposition of any other nitrate, the nitrous gas being displaced by the superior affinity of the alkali for the acid.
“Agreeable to this theory, the salts denominatednitritesare in fact triple salts, or ternary combinations of nitric acid, nitrous gas, and salifiable bases.”
This theory is perfectly new to me. Other Chemists to whom I have mentioned it, have likewise considered it as new. Yet in a subsequent letter Mr. Thomson mentions that he had been told of the belief of a similar opinion among the French Chemists.
[34]In some experiments made on the nitrites of potash, and of ammoniac, before I was well acquainted with the composition of nitric acid, I found that a light olive-colored acid of 1,28, was capable of being saturated by weak solutions of potash and ammoniac, without losing any nitrous gas; but after the evaporation of the neutralised solution, at very low temperatures, the salts in all their properties resemblednitrates.
[34]In some experiments made on the nitrites of potash, and of ammoniac, before I was well acquainted with the composition of nitric acid, I found that a light olive-colored acid of 1,28, was capable of being saturated by weak solutions of potash and ammoniac, without losing any nitrous gas; but after the evaporation of the neutralised solution, at very low temperatures, the salts in all their properties resemblednitrates.
[35]As is evident from the curious appearance of the dark green spherules, repulsive both to water, and light green acid.
[35]As is evident from the curious appearance of the dark green spherules, repulsive both to water, and light green acid.
[36]That is, undecompounded.
[36]That is, undecompounded.
[37]The existence of these bodies will be hereafter proved.
[37]The existence of these bodies will be hereafter proved.
[38]The blue green acid is not homogeneal in its composition, it is composed of the blue green spherules and the bright green acid. The blue green spherules are of greater specific gravity than the dark green acid, probably because they contain little or no water.
[38]The blue green acid is not homogeneal in its composition, it is composed of the blue green spherules and the bright green acid. The blue green spherules are of greater specific gravity than the dark green acid, probably because they contain little or no water.
[39]The composition of the acids thus marked, is given from calculations.
[39]The composition of the acids thus marked, is given from calculations.
[40]Nitrous gas contains 44,05 Nitrogene, and 55,95 Oxygene, as has been said before.
[40]Nitrous gas contains 44,05 Nitrogene, and 55,95 Oxygene, as has been said before.
[41]A great portion of it, of course, dissolved in the water with the nitrous acid carried over.
[41]A great portion of it, of course, dissolved in the water with the nitrous acid carried over.
[42]Their changes of volume, corresponding to changes of temperature, most probably, are likewise different.
[42]Their changes of volume, corresponding to changes of temperature, most probably, are likewise different.
[43]Probably in the ratio of the square of the quantity of water united to it.
[43]Probably in the ratio of the square of the quantity of water united to it.
[44]The quantities of Oxygene and Nitrogene in any solution, may be thus found—— Let A = the true acid, X the oxygene, and Y the nitrogene.Then238 AAX =———and Y =———239239
[44]The quantities of Oxygene and Nitrogene in any solution, may be thus found—— Let A = the true acid, X the oxygene, and Y the nitrogene.
Then
[45]Experiments and Observations; last edition, vol. 1, page 384.
[45]Experiments and Observations; last edition, vol. 1, page 384.
[46]Nitrous gas, holding in solution nitrous acid, is more readily absorbed by water than when in its pure form, from being presented to it in a more condensed state in the green acid, formed by the contact of water and nitrous vapor.
[46]Nitrous gas, holding in solution nitrous acid, is more readily absorbed by water than when in its pure form, from being presented to it in a more condensed state in the green acid, formed by the contact of water and nitrous vapor.
[47]Mem. des Savans Etrangers, v. xi. 226. Vide Kirwan sur le phlogistique pag. 110.
[47]Mem. des Savans Etrangers, v. xi. 226. Vide Kirwan sur le phlogistique pag. 110.
[48]In this experiment, as well as in the last, some of the mixture was thrown into the jar undecompounded.
[48]In this experiment, as well as in the last, some of the mixture was thrown into the jar undecompounded.
[49]To detach the potash from the carbonic acid.
[49]To detach the potash from the carbonic acid.
[50]This nitrogene contained a little nitrous gas, as it gave red fumes when exposed to the air. The free nitrous acid was decomposed by the mercury, as it was not covered with water.
[50]This nitrogene contained a little nitrous gas, as it gave red fumes when exposed to the air. The free nitrous acid was decomposed by the mercury, as it was not covered with water.
[51]Essay on phlogiston.
[51]Essay on phlogiston.
[52]Dr. Priestley says, “Having filled a phial containing exactly the quantity of four pennyweights of water, with strong, pale, yellow spirit of nitre, with its mouth quite close to the top of a large receiver standing in water, I carefully drew out almost all the common air, and then filled it with nitrous air; and as this was absorbed, I kept putting in more and more, till in less than two days it had completely absorbed 130 ounce measures. Presently after this process began, the surface of the acid assumed a deep orange color, and when 20 or 30 ounce measures of air were absorbed, it became green at the top: this green descended lower and lower, till it reached the bottom of the phial. Towards the end of the process, the evaporation was perceived to be very great, and when I took it out, the quantity was found to have diminished to one half. Also it had become, by means of this process, and the evaporation together, exceeding weak, and was rather blue than green.”Experiments and Observations, vol. 1, p. 384. Last edition.
[52]Dr. Priestley says, “Having filled a phial containing exactly the quantity of four pennyweights of water, with strong, pale, yellow spirit of nitre, with its mouth quite close to the top of a large receiver standing in water, I carefully drew out almost all the common air, and then filled it with nitrous air; and as this was absorbed, I kept putting in more and more, till in less than two days it had completely absorbed 130 ounce measures. Presently after this process began, the surface of the acid assumed a deep orange color, and when 20 or 30 ounce measures of air were absorbed, it became green at the top: this green descended lower and lower, till it reached the bottom of the phial. Towards the end of the process, the evaporation was perceived to be very great, and when I took it out, the quantity was found to have diminished to one half. Also it had become, by means of this process, and the evaporation together, exceeding weak, and was rather blue than green.”
Experiments and Observations, vol. 1, p. 384. Last edition.
[53]See Mr. Keir’s excellent observations on this subject. Chem. Dict. Art. Acid.
[53]See Mr. Keir’s excellent observations on this subject. Chem. Dict. Art. Acid.
[54]Irish Transactions, vol. 4, p. 34.
[54]Irish Transactions, vol. 4, p. 34.
[55]Addit. Obs. pag. 74.
[55]Addit. Obs. pag. 74.
[56]Additional Observations, page 70.
[56]Additional Observations, page 70.
[57]Elements, pag. 103, Kerr’s Translation.
[57]Elements, pag. 103, Kerr’s Translation.
[58]Mem. Acad. 1787.
[58]Mem. Acad. 1787.
[59]As well as oxygene and nitrogene, Mr. Watt’s experiments prove that much phlogisticated nitrous acid is produced.
[59]As well as oxygene and nitrogene, Mr. Watt’s experiments prove that much phlogisticated nitrous acid is produced.
[60]Journal de Physique, 1786. Tom. 2, pag. 176.
[60]Journal de Physique, 1786. Tom. 2, pag. 176.
[61]Though the tube had never been used, and was apparently clean and dry on the inside, it must have contained something in the form of dust, capable of furnishing either hydrocarbonate, or charcoal.
[61]Though the tube had never been used, and was apparently clean and dry on the inside, it must have contained something in the form of dust, capable of furnishing either hydrocarbonate, or charcoal.
[62]Journal de Physique, 1786, t. 2, 177.
[62]Journal de Physique, 1786, t. 2, 177.
[63]Phil. Trans. vol. 79, page 294.
[63]Phil. Trans. vol. 79, page 294.
[64]Vol. 2, page 398.
[64]Vol. 2, page 398.
[65]Ammoniac generated at a temperature above that of the atmosphere, always deposits ammoniacal solution during its reduction to the common temperature.
[65]Ammoniac generated at a temperature above that of the atmosphere, always deposits ammoniacal solution during its reduction to the common temperature.
[66]By the introduction of aëriform ammoniac into the exhausted globe.
[66]By the introduction of aëriform ammoniac into the exhausted globe.
[67]Additional Observations, page 107.
[67]Additional Observations, page 107.
[68]It is necessary in these experiments, that the greatest care be observed in the introduction and extraction of the capillary tube. If it is introduced dry, there will be a source of error from the moisture adhering to it when taken out. I therefore always wetted it before its introduction, and took care that no more fluid adhered to it after the experiment, than before.
[68]It is necessary in these experiments, that the greatest care be observed in the introduction and extraction of the capillary tube. If it is introduced dry, there will be a source of error from the moisture adhering to it when taken out. I therefore always wetted it before its introduction, and took care that no more fluid adhered to it after the experiment, than before.
[69]Previous to those experiments, I had made a number of others on the combination of ammoniac with water.—My design was, to ascertain the diminution of specific gravity for every three grains of ammoniac absorbed; but this I found impossible. The capillary tube, when taken out of the phial, always carried with it a minute portion of the solution, which partially evaporated before it could be again introduced; and thus the sources of error increased in proportion to the number of examinations.
[69]Previous to those experiments, I had made a number of others on the combination of ammoniac with water.—My design was, to ascertain the diminution of specific gravity for every three grains of ammoniac absorbed; but this I found impossible. The capillary tube, when taken out of the phial, always carried with it a minute portion of the solution, which partially evaporated before it could be again introduced; and thus the sources of error increased in proportion to the number of examinations.
[70]The expansion from increase of temperature is probably great in proportion to the quantity of ammoniac in the solution.
[70]The expansion from increase of temperature is probably great in proportion to the quantity of ammoniac in the solution.
[71]From the combination.
[71]From the combination.
[72]I had before proved that at this temperature the salt neither decomposed nor sublimed.
[72]I had before proved that at this temperature the salt neither decomposed nor sublimed.
[73]A particular account of the experiments from which these facts were deduced, was printed in September, and will appear in the first volume of theResearches.
[73]A particular account of the experiments from which these facts were deduced, was printed in September, and will appear in the first volume of theResearches.
[74]And which will be published, with an account of its perfect decomposition at a high temperature, in theResearches.
[74]And which will be published, with an account of its perfect decomposition at a high temperature, in theResearches.
[75]When nitrous gas exists in neutro-saline solutions, they are always colored more or less intensely, from yellow to olive, in proportion to the quantity combined with them.
[75]When nitrous gas exists in neutro-saline solutions, they are always colored more or less intensely, from yellow to olive, in proportion to the quantity combined with them.
[76]Hence a nitrate of ammoniac with excess of acid, when exposed to heat, first becomes yellow, and then white.
[76]Hence a nitrate of ammoniac with excess of acid, when exposed to heat, first becomes yellow, and then white.
[77]The accounts given by different chemists of the composition of nitrate of ammoniac, are extremely discordant; they have been chiefly deduced from decompositions of carbonate of ammoniac (the varieties of which have been heretofore unknown) by nitrous acids of unknown degrees of nitration. Hence they are particularly erroneous with regard to the alkaline part. Wenzel supposes it to be 32 per cent, and Kirwan 24.Addit. Observ.pag. 120.
[77]The accounts given by different chemists of the composition of nitrate of ammoniac, are extremely discordant; they have been chiefly deduced from decompositions of carbonate of ammoniac (the varieties of which have been heretofore unknown) by nitrous acids of unknown degrees of nitration. Hence they are particularly erroneous with regard to the alkaline part. Wenzel supposes it to be 32 per cent, and Kirwan 24.Addit. Observ.pag. 120.
[78]Mem. Par. 1783. See Irish Trans. vol. 4.
[78]Mem. Par. 1783. See Irish Trans. vol. 4.
[79]Addit. Obs. pag. 120.
[79]Addit. Obs. pag. 120.
[80]Two measures of air dispelled from this water by boiling, mingled with 2 of nitrous gas, diminished to 2,4 nearly.
[80]Two measures of air dispelled from this water by boiling, mingled with 2 of nitrous gas, diminished to 2,4 nearly.
[81]Experiments and Observations, vol. 2, pag. 89. Last Edition.
[81]Experiments and Observations, vol. 2, pag. 89. Last Edition.
[82]A minute quantity, however, must have been absorbed, and given out again when the charcoal was heated.
[82]A minute quantity, however, must have been absorbed, and given out again when the charcoal was heated.
[83]Strong solution of ammoniac has no attraction for nitrous oxide.
[83]Strong solution of ammoniac has no attraction for nitrous oxide.
[84]The gas was examined by those tests in order to prove that no water had been decomposed.
[84]The gas was examined by those tests in order to prove that no water had been decomposed.
[85]See the curious paper of this excellent philosopher, on the combustion of the diamond, in which he proves that charcoal is, in fact, oxide of diamond. Annales de Chimie, xxxi.
[85]See the curious paper of this excellent philosopher, on the combustion of the diamond, in which he proves that charcoal is, in fact, oxide of diamond. Annales de Chimie, xxxi.
[86]This was actually the case; for on examining the conducting tube the day after the experiment, some minute crystals of prismatic nitrate of ammoniac were perceived in it.
[86]This was actually the case; for on examining the conducting tube the day after the experiment, some minute crystals of prismatic nitrate of ammoniac were perceived in it.
[87]Owing part of their weight to an unknown quantity of water.
[87]Owing part of their weight to an unknown quantity of water.
[88]Mem. de Paris. 1785, and Journal de Physique, 1786, page 175.
[88]Mem. de Paris. 1785, and Journal de Physique, 1786, page 175.
[89]The absorption of nitrous gas by sulphate of iron, &c. will be treated of in the next division.
[89]The absorption of nitrous gas by sulphate of iron, &c. will be treated of in the next division.
[90]As is evident from the decomposition of ammoniac by heat.
[90]As is evident from the decomposition of ammoniac by heat.
[91]Nitric acid is phlogisticated by heat, as appears from Dr. Priestley’s experiments. Vol. 3, p. 26.
[91]Nitric acid is phlogisticated by heat, as appears from Dr. Priestley’s experiments. Vol. 3, p. 26.
[92]As is evident from the increase of temperature required for the formation of water.
[92]As is evident from the increase of temperature required for the formation of water.
[93]For ammoniac and nitrous oxide are both decomposed at the red heat, and oxygene given out from nitric acid when it is passed through a heated tube.
[93]For ammoniac and nitrous oxide are both decomposed at the red heat, and oxygene given out from nitric acid when it is passed through a heated tube.
[94]Whenever nitrous acid is produced at high temperatures, it is always highly phlogisticated, provided it has not been long in contact with oxygene. When Dr. Priestley passed nitric acid through a tube heated red, he procured much oxygene, and phlogisticated acid; and the water in the apparatus employed was fully impregnated with nitrous air. Hence it would appear, that heat diminishes the attraction between oxygene and nitrous gas, and increases the affinity of nitrous gas for nitrous acid. Mr.James Thomson, whose theory of the Nitrous Acid I have already mentioned, from some experiments on the phlogistication of Nitric Acid by heat, which he has communicated to me, concludes with great justness, that a portion of the acid is always completely decomposed in this process: the oxygene liberated, and the nitrous gas combined with the remaining acid.
[94]Whenever nitrous acid is produced at high temperatures, it is always highly phlogisticated, provided it has not been long in contact with oxygene. When Dr. Priestley passed nitric acid through a tube heated red, he procured much oxygene, and phlogisticated acid; and the water in the apparatus employed was fully impregnated with nitrous air. Hence it would appear, that heat diminishes the attraction between oxygene and nitrous gas, and increases the affinity of nitrous gas for nitrous acid. Mr.James Thomson, whose theory of the Nitrous Acid I have already mentioned, from some experiments on the phlogistication of Nitric Acid by heat, which he has communicated to me, concludes with great justness, that a portion of the acid is always completely decomposed in this process: the oxygene liberated, and the nitrous gas combined with the remaining acid.
[95]Except it be gold or platina.
[95]Except it be gold or platina.
[96]A pound of nitrate of ammoniac costs about 5s. 10d. This pound, properly decomposed, produces rather more than 34 moderate doses of air; so that the expence of a dose is about 2d. What fluid stimulus can be procured at so cheap a rate?
[96]A pound of nitrate of ammoniac costs about 5s. 10d. This pound, properly decomposed, produces rather more than 34 moderate doses of air; so that the expence of a dose is about 2d. What fluid stimulus can be procured at so cheap a rate?
[97]Experiments and Observations, vol. II. pag. 50. Last Edition.
[97]Experiments and Observations, vol. II. pag. 50. Last Edition.
[98]That is, charcoal produced by the decomposition of spirits of wine. Vol. II. pag. 39.
[98]That is, charcoal produced by the decomposition of spirits of wine. Vol. II. pag. 39.
[99]Dr. Priestley says, “having heated iron in nitrous air, I proceeded to heat in the same air, a piece of charcoal not long after it had been subjected to a strong heat covered with sand. The sun not shining immediately, after the charcoal was introduced into the vessel of air, through the mercury by which it was confined, part of the air was absorbed; but on heating the charcoal, the quantity was increased. Having continued the progress as long as I thought necessary, I examined the air and found it to be about as much as the original quantity of nitrous air; but it was all phlogisticated air extinguishing a candle and having no mixture of fixed air in it.”—Experiments and Observations, Vol. II, page 39.
[99]Dr. Priestley says, “having heated iron in nitrous air, I proceeded to heat in the same air, a piece of charcoal not long after it had been subjected to a strong heat covered with sand. The sun not shining immediately, after the charcoal was introduced into the vessel of air, through the mercury by which it was confined, part of the air was absorbed; but on heating the charcoal, the quantity was increased. Having continued the progress as long as I thought necessary, I examined the air and found it to be about as much as the original quantity of nitrous air; but it was all phlogisticated air extinguishing a candle and having no mixture of fixed air in it.”—Experiments and Observations, Vol. II, page 39.
[100]That is, sulphate of iron containing oxide of iron, in the first degree of oxygenation.
[100]That is, sulphate of iron containing oxide of iron, in the first degree of oxygenation.
[101]That is, carbon, or oxide of diamond.
[101]That is, carbon, or oxide of diamond.
[102]That is, blue prussiate of iron.
[102]That is, blue prussiate of iron.
[103]No luminous appearance is produced when phosphorus is introduced intopurenitrous gas. It has been often observed, that phosphorus is luminous in nitrous gas, that has not been long in contact with water after its production. This phænomenon, I suspect, depends either on the decomposition of the nitric acid held in solution by the nitrous gas; or on the combination of the phosphorus with oxygene loosely adhering to the binary aëriform compound of nitric acid and nitrous gas. I have not yet examined if nitrous gas can be converted into nitrous oxide by long exposure to heated phosphorus: it appears, however, very probable.
[103]No luminous appearance is produced when phosphorus is introduced intopurenitrous gas. It has been often observed, that phosphorus is luminous in nitrous gas, that has not been long in contact with water after its production. This phænomenon, I suspect, depends either on the decomposition of the nitric acid held in solution by the nitrous gas; or on the combination of the phosphorus with oxygene loosely adhering to the binary aëriform compound of nitric acid and nitrous gas. I have not yet examined if nitrous gas can be converted into nitrous oxide by long exposure to heated phosphorus: it appears, however, very probable.
[104]Perhaps this fact has been noticed before; I have not, however, met with it in any chemical work.
[104]Perhaps this fact has been noticed before; I have not, however, met with it in any chemical work.
[105]This mode of inflaming bodies in gases, not capable of supporting combustion at low temperatures, will be particularly described hereafter.
[105]This mode of inflaming bodies in gases, not capable of supporting combustion at low temperatures, will be particularly described hereafter.
[106]Elements English Trans. edit. i. pag. 216.
[106]Elements English Trans. edit. i. pag. 216.
[107]Experiments and Observations, Vol. II. pag. 40, 2d. Ed.
[107]Experiments and Observations, Vol. II. pag. 40, 2d. Ed.
[108]He says, “On a observé, (depuis qu’on travaille sur le pureté de l’air) que le gaz nitreux, secoué avec l’eau, en souffre une diminution de volume. Quelques physiciens attribuent ce changement à une vraie absorption, à une dissolution du gaz nitreux dans l’eau; d’autres à l’air contenu dans les interstices de tous les fluides. Le cit. Vanbreda, à Delft, a fait des recherches très-exactes sur l’influence des eaux de pluie et de puit, sur les nombres eudiométriques; et les belles expériences du cit. Hassenfratz, sur l’abondance d’oxygène, contenue dans les eaux de neige et de pluie, sont supposer que l’air des interstices de l’eau joue un rôle important dans l’absorption du gaz nitreux. En comparant ces effets avec les phénomènes observé dans la decomposition du sulfate de fer, nous supposâmes, le cit. Tassaert et moi, que le simple contact du gaz nitreux avec l’eau distillée pourroit bien causer une décomposition de ce dernier. Nous examinâmes soigneusement une petite quantité d’eau distillée, secouée avec beaucoup de gas nitreux trés-pur, et nous trouvâmes, au moyen de la terre calcaire, et l’acide muriatique, qu’il s’y forme dunitrate d’ammoniaque. L’eau se décompose en cette opération, par un double affinité de l’oxygene pour le gaz nitreux, et de l’hydrogène pour l’azote; il se forme de l’acide nitrique et de l’ammoniaque; et, quoique la quantité du dernier paroisse trop petite pour en évaluer exactment la quantité, son existence cependant se manifeste, (à ne pas sans douter) par le dégagement des vapeurs, qui blanchissent dans la proximité de l’acide muriatique. Voilá un fait bien frappant que la composition d’une substance alcaline par le contact d’une acide, et de l’eau.”Annales de Chimie, t. xxviii. pag. 153.
[108]He says, “On a observé, (depuis qu’on travaille sur le pureté de l’air) que le gaz nitreux, secoué avec l’eau, en souffre une diminution de volume. Quelques physiciens attribuent ce changement à une vraie absorption, à une dissolution du gaz nitreux dans l’eau; d’autres à l’air contenu dans les interstices de tous les fluides. Le cit. Vanbreda, à Delft, a fait des recherches très-exactes sur l’influence des eaux de pluie et de puit, sur les nombres eudiométriques; et les belles expériences du cit. Hassenfratz, sur l’abondance d’oxygène, contenue dans les eaux de neige et de pluie, sont supposer que l’air des interstices de l’eau joue un rôle important dans l’absorption du gaz nitreux. En comparant ces effets avec les phénomènes observé dans la decomposition du sulfate de fer, nous supposâmes, le cit. Tassaert et moi, que le simple contact du gaz nitreux avec l’eau distillée pourroit bien causer une décomposition de ce dernier. Nous examinâmes soigneusement une petite quantité d’eau distillée, secouée avec beaucoup de gas nitreux trés-pur, et nous trouvâmes, au moyen de la terre calcaire, et l’acide muriatique, qu’il s’y forme dunitrate d’ammoniaque. L’eau se décompose en cette opération, par un double affinité de l’oxygene pour le gaz nitreux, et de l’hydrogène pour l’azote; il se forme de l’acide nitrique et de l’ammoniaque; et, quoique la quantité du dernier paroisse trop petite pour en évaluer exactment la quantité, son existence cependant se manifeste, (à ne pas sans douter) par le dégagement des vapeurs, qui blanchissent dans la proximité de l’acide muriatique. Voilá un fait bien frappant que la composition d’une substance alcaline par le contact d’une acide, et de l’eau.”
Annales de Chimie, t. xxviii. pag. 153.
[109]Which was certainly as free from air as it ever can be obtained.
[109]Which was certainly as free from air as it ever can be obtained.
[110]Dr. Priestley found distilled water, saturated with nitrous air, to acquire an astringent taste and pungent smell. In some unboiled impregnated pump water, I once thought that I perceived a subacid taste; but it was extremely slight, and probably owing to nitrous acid formed by the union of the oxygene of the common air in the water, with some of the nitrous gas.
[110]Dr. Priestley found distilled water, saturated with nitrous air, to acquire an astringent taste and pungent smell. In some unboiled impregnated pump water, I once thought that I perceived a subacid taste; but it was extremely slight, and probably owing to nitrous acid formed by the union of the oxygene of the common air in the water, with some of the nitrous gas.
[111]As carbonic acid and ammoniac are both products of animalisation, is it not probable that our common waters particularly those in, and near towns and cities, contain carbonate of ammoniac? If so, this salt will always exist in them after distillation. In the experiments on carbonate of ammoniac, to which I have often alluded, I found, in distilling a solution of this salt in water, that before half of the water had passed into the recipient, the carbonate of ammoniac had sublimed; so that the distilled solution was much stronger than before, whilst the water remaining in the retort was tasteless. Will this supposition at all explain Humbolt’s mistake?
[111]As carbonic acid and ammoniac are both products of animalisation, is it not probable that our common waters particularly those in, and near towns and cities, contain carbonate of ammoniac? If so, this salt will always exist in them after distillation. In the experiments on carbonate of ammoniac, to which I have often alluded, I found, in distilling a solution of this salt in water, that before half of the water had passed into the recipient, the carbonate of ammoniac had sublimed; so that the distilled solution was much stronger than before, whilst the water remaining in the retort was tasteless. Will this supposition at all explain Humbolt’s mistake?
[112]The water still being unity.
[112]The water still being unity.
[113]He says “100 parties de gaz nitreux, (à 0.14 d’azote) secouées avec l’eau distillée, récemment cuite, diminuent en volume de 0.11, ou 0.12. Ce même gaz, en contact avec l’eau de puits, ne perd que 0.02. La cause de cette différence de 0.9, ou 0.10, ne doit pas être attribuée ni à l’impurité de l’air atmosphérique, contenu dans les interstices de l’eau, ni à la décomposition de cette eau même. Elle n’est qu’apparente; car l’acide nitrique, qui se forme par le contact du gaz nitreux avec l’eau de puits, en décompose le carbonate de chaux. Il se dégage de l’acide carbonique, qui, en augmentant le volume du residu, rend l’absorption du gaz nitreux moins sensible. Pour déterminer la quantité de cet acide carbonique, je lavai le résidu avec de l’eau de chaux. Dans un grand nombre d’expériences, le volume diminua de 0.09, ou 0.07. Il faut en conduire que l’eau de puits absorbe réellement 9 + 2, ou 7 + 2 parties de gas nitreux, c’est-à-dire, à peu-près la même quantité que l’eau distillée.”Annales De Chimie, xxviii. pag. 154.
[113]He says “100 parties de gaz nitreux, (à 0.14 d’azote) secouées avec l’eau distillée, récemment cuite, diminuent en volume de 0.11, ou 0.12. Ce même gaz, en contact avec l’eau de puits, ne perd que 0.02. La cause de cette différence de 0.9, ou 0.10, ne doit pas être attribuée ni à l’impurité de l’air atmosphérique, contenu dans les interstices de l’eau, ni à la décomposition de cette eau même. Elle n’est qu’apparente; car l’acide nitrique, qui se forme par le contact du gaz nitreux avec l’eau de puits, en décompose le carbonate de chaux. Il se dégage de l’acide carbonique, qui, en augmentant le volume du residu, rend l’absorption du gaz nitreux moins sensible. Pour déterminer la quantité de cet acide carbonique, je lavai le résidu avec de l’eau de chaux. Dans un grand nombre d’expériences, le volume diminua de 0.09, ou 0.07. Il faut en conduire que l’eau de puits absorbe réellement 9 + 2, ou 7 + 2 parties de gas nitreux, c’est-à-dire, à peu-près la même quantité que l’eau distillée.”
Annales De Chimie, xxviii. pag. 154.
[114]Nicholson’s Phil. Jour. No. 1, p. 453.
[114]Nicholson’s Phil. Jour. No. 1, p. 453.
[115]I have been able to make these observations on the sulphates of iron, most of them after Proust.
[115]I have been able to make these observations on the sulphates of iron, most of them after Proust.
[116]Annales de Chimie, vol. xxviii. pag. 182.
[116]Annales de Chimie, vol. xxviii. pag. 182.
[117]Division IV. Section 5.
[117]Division IV. Section 5.
[118]Division II. Section 1.
[118]Division II. Section 1.