Mr. Pepys has also extended the principle for the preservation of steel instruments by guards of zinc: razors and lancets may be thus defended with perfect success. In the construction of monuments which are to transmit to posterity the record of important events, the artist will be careful in avoiding the contact of different metals: it is thus that the Etruscan inscriptions, engraved upon pure lead, are preserved to the present day; while medals of mixed metals of a much more recent date are corroded.
Numerous are the facts daily presented before us, which receive from this principle a satisfactory explanation. To the philosopher, the examination of its agencies will furnish a perpetual source of instruction and amusement; and I will here enumeratea few simple instances of its effects: in the first place, for the purpose of showing that, whenever a principle or discovery involves or unfolds a law of Nature, its applications are almost inexhaustible, and that, however abstracted it may appear, it is sooner or later employed for the common purposes of life; and in the next place, in the hope of convincing the reader, that there does not exist any source of pleasure so extensive and so permanent as that derived from the stores of philosophy. The saunterer stumbles over the stone that may cross his path, and vents only his vexation at the interruption; but to the philosopher there is not a body, animate or inanimate, with which he can come in contact, that does not yield its treasures at his approach, and contribute to extend the pleasures of his existence.
I well remember some years ago, that, in passing through Deptford, my curiosity was excited by the extraordinary brilliancy of a portion of the gilded sign of an inn in that town, while its other parts had entirely lost their metallic lustre. Having obtained a ladder, I ascended to the sign, in order, if possible, to solve the problem that had so greatly interested me: the mystery immediately vanished; for an iron nail appeared in the centre of the spot, which had protected the copper leaf for several inches around it. Any person may easily satisfy himself of the efficacy of such protection, in his rambles through the metropolis, by noticing the gilded, or rather coppered, sugar-loaves[104]so commonlysuspended over the shops of grocers, when he will frequently perceive that the parts into which the iron supports have entered, unless the latter have been painted, shine preeminently brilliant. If a still more familiar example of the effect of a simple Voltaic circuit be required, it is afforded by the iron palisadoes, where the iron is constantly corroded at its point of contact with the lead by which it is cemented into the stone. These examples are not only interesting from their simplicity, but from their demonstrating the small quantity of a conducting fluid which is sufficient to transmit the electrical power, or to complete a simple circuit: a fact which, it will be remembered, the experiments of Davy had before established.[105]
As our knowledge advances, these principles will no doubt derive other illustrations, and be found capable of more extensive application; for as yet we are but in the infancy of the enquiry. I have lately been engaged in a series of experiments, the results of which, I confidently anticipate, will lead to some new facts connected with the changes produced on the negative metal of a Voltaic circuit; an account of which I hope shortly to submit to the Royal Society. I shall on this occasion merely notice one result, which appears to me to admit of an immediate application to one of the most important circumstances of life—the purity of water contained in leaden cisterns.
My attention has for several years been directed to the state of the water with which the metropolis is supplied; and upon having been lately requestedto propose a remedy for preventing the action of a spring in the neighbourhood of London upon lead, which it had been found to corrode in a very rapid manner, I suggested the expediency of protecting the pipes and cisterns with surfaces of iron; but before such a plan was put in execution, I proposed to try its efficacy in the laboratory:—the first result was very startling; for, instead of preventing, as I had anticipated, I found that it greatly increased, the solution of the lead. After various experiments, I arrived at the conclusion, that lead, when rendered negative by iron, and placed in contact with weak saline solutions,—such, for instance, as common spring water,—was dissolved; in consequence of the decomposition of the salts and the transference of their elements according to the general law, the acid passing to the iron, and the alkali to the lead; and so powerfully is this latter body acted upon by an alkali, that, if a slip of it be immersed in a solution of potash or soda, its crystalline texture is so rapidly developed, that its surface exhibits an appearance similar to that presented by tin-plate, and which is designated by the termmoirée.
I apprehend that most of the anomalous cases of the solution of lead in common water, which have for so many years embarrassed the chemist, may thus receive an explanation. An eminent physician lately informed me, that some time since he was called upon to attend a family who had evidently suffered from the effects of saturnine poison, and that he well remembers there was an iron pump in the cistern that supplied the water. Upon showing the results of my experiment to a no lesseminent chemist, he was immediately reminded of a circumstance which occurred at Islington, where the water was found to corrode the lead in which it was received: in this vessel there was an iron bar; and the fact would not have attracted his notice, nor have been impressed upon his recollection, but from the unusual state of corrosion in which it appeared.
I shall conclude these observations by an account of "the change which some musket balls, taken out of Shrapnell's shells, had undergone," by Mr. Faraday, and which is published in the 16th volume of the Quarterly Journal of Science, for the year 1823. This history is not only interesting on account of the high chemical character of its author, but satisfactory as being in direct opposition to previously established facts; and cannot therefore have received any bias from preconceived theory.
"Mr. Marsh of Woolwich gave me some musket balls, which had been taken out of Shrapnell's shells. The shells had lain in the bottoms of ships, and probably had sea-water amongst them. When the bullets are put in, the aperture is merely closed by a common cork. These bullets were variously acted upon: some were affected only superficially, others more deeply, and some were entirely changed. The substance produced is hard and brittle; it splits on the ball, and presents an appearance like some hard varieties of hæmatite; its colour is brown, becoming, when heated, red; it fuses on platinum foil into a yellow flaky substance like litharge. Powdered and boiled in water, no muriatic acid or lead was found in solution. It dissolved in nitric acid without leaving any residuum, and the solution gavevery faint indications only of muriatic acid. It is aprotoxide of lead, perhaps formed, in some way, by the galvanic action of the iron shell and the leaden ball, assisted probably by the sea-water. It would be very interesting to know the state of the shells in which a change like this has taken place to any extent.It might have been expected, that as long as any iron remained, the lead would have been preserved in the metallic state."
In one experiment, I found that a piece of lead protected by iron underwent solution in water containing nitrate of potash, while it resisted the action of very dilute nitric acid: upon this point, however, farther enquiry is necessary; for I subsequently failed in producing the same effect, owing, no doubt, to having employed too strong an acid.
Let us return from this digression to the subject of Sir Humphry Davy's Protectors. It only remains for me to relate the results which followed the practical application of the Voltaic principles which his various experiments had developed.
In the month of May 1824, directions were issued by the Lords of the Admiralty to protect, in future, the copper sheathing of all his Majesty's ships which might be taken into dock, upon the plan proposed by Sir Humphry Davy.
The protectors were bars of iron six inches wide at their base, three inches in thickness in their centre, and, in outward form, the segment of an extended circle. They were usually placed on each side of the ship in a horizontal position, viz. in midships about three feet under water—on the keel in a line with these—and the remainder in the foreand afterparts of the ship (about three feet under the line of fluitation), as far forward and abaft as the curvatures of their respective bodies would allow of their lying flat upon the surface of the copper.
As it is difficult by verbal description alone to convey a sufficiently distinct idea of this subject to persons unacquainted with naval architecture, I have introduced a sketch, exhibiting thegeneralposition of theProtectors, although they are necessarily exaggerated in size, or they would have appeared as mere specks upon the drawing.
A. A. Line of Fluitation.
A. A. Line of Fluitation.
A. A. Line of Fluitation.
On several ships, some of the protectors, in the stem and the stern, were placedvertically; in which case they were fastened to the stems and stern-posts; and in this manner they were found to act more powerfully in preserving the copper, than when they were all placed horizontally. The ends of the protectors were rounded, in order to prevent any great resistance to the water, and they were fastened to the bottoms of the ships with copper bolts, the iron being counter-sunk to receive their heads, and the holes were then filled with carbonate of lime, or Parker's cement. To bring about the best possible contact of all the copper sheets, their edges, which lap over each other, where the nails are driven to fasten them to the ships, were rubbed bright, first with sand-paper, and finally with glass-paper.
Shortly after the ships thus protected were sent to sea, it was evident to all on board, from their dull sailing, that the bottoms had become very foul; and on being examined in dry docks, it was found that the copper was completely covered with sea-weed, shell-fish of various kinds, and myriads of small marine insects. Upon their removal, however, it was found, on weighing the sheets, that the copper had suffered little or no loss; thus proving that, although its practical application had failed from unforeseen circumstances, the principle of protection was true, and had fully justified the expectation of its success.
The copper near the protectors was much more foul than that at a greater distance from them; and there was, moreover, a considerable deposit of carbonate of lime, and of carbonate and hydrate of magnesia, in their vicinity.
Sir Humphry Davy immediately suggested, as a remedy for this evil, that the bottoms should be scraped, and the copper washed with a small quantity of acidulous water; and he also proposed that the protectors should in future be placed under, instead of over, the copper sheathing. This plan was immediately adopted. Discs of cast-iron three and a half inches in diameter, and one-fourth of an inch in thickness, were let into the plank of the bottom of the Glasgow, of fifty guns, on the starboard side only—the larboard side having been left without any protection. These discs were in the proportion of one to every four sheets of copper, and over them were placed pieces of brown paper, and over the paper thin sheet-lead, so that the lattermetal was in contact with the copper sheathing. A similar experiment was also tried on the Zebra, of eighteen guns, substituting, however, discs of zinc[106]for those of iron.
The bottom of the Glasgow was examined twelve months afterwards, when the discs of iron were found oxidated throughout, presenting in their appearance the characters of plumbago. The copper on the starboard side was preserved, but covered with weeds and shell-fish. The sheets on the larboard had undergone the usual waste, but were clean.
The Zebra was docked four years after the experiment had commenced, when the zinc protectors were perfect, and it did not appear that they had exerted any influence in preserving the copper, as it had wasted equally on both sides. It may be presumed in this case that the Voltaic circuit had by some fault in the arrangement been interrupted.
The apparent conversion of iron into a substance resembling plumbago, by the action of sea-water, has been frequently noticed. The protectors thus changed[107]were, to a considerable depth from thesurface, so soft as to be easily cut by a knife; but after being exposed for some time to the action of the atmosphere, they became harder, and even brittle. A portion of this soft substance having been wrapped in paper for the purpose of examination, and placed in the pocket of a shipwright, gave rise to a very curious and unexpected result: at first, the artist, like Futitorious with his chestnuts, thought he perceived a genial warmth; but the effect was shortly less equivocal; the substance became hot, and presently passed into a state of absolute ignition. Various theories have been suggested for its explanation: Mr. Daniell has advanced an opinion which supposes the formation of silicon, and thus accounts for the spontaneous ignition by the action of air.
The disadvantages which arise from the foulness of ships' bottoms, particularly when on foreign stations, where there are no dry docks to receive them, are so serious, that the Government was obliged, in July 1825, to order the discontinuance of the protectors on all sea-going ships; but directed that they should still be used upon all those that were laid up in our ports. When, however, an examination of the latter took place, they were found tobe much more foul than those which had been in motion at sea: shell-fish of various kinds had adhered to them so closely, that it was even necessary to use percussion to remove them, which not only indented the copper, but in many instances actually fractured it.
Under all these discouraging circumstances, the unwelcome conviction was forced upon the agents of Government, that the plan was incapable of successful application, and it was accordingly altogether abandoned in September 1828.
Such were the results of the experiments carried on in the ports of England, for the protection of copper sheathing, from the success of which Sir H. Davy justly expected honours, fame, and reward. That his disappointment was great, may be readily imagined, and it is supposed to have had a marked influence upon his future character. It is much to be regretted that his vexation should have been heightened by the unjust and bitter attacks made upon him by the periodical press, and by those subalterns in science, who, unable to appreciate the beauty of the principle he had so ably developed, saw only in its details an object for sarcasm, and in its failure an opportunity for censure; while those whose stations should have implied superior knowledge, in the pride and arrogance of assumed contempt, sought a refuge from the humiliation of ignorance.
That Davy was severely hurt by these attacks, is a fact well known to his friends. In a letter to Mr. Children he says: "A mind of much sensibility might be disgusted, and one might be induced tosay, Why should I labour for public objects, merely to meet abuse?—I am irritated by them more than I ought to be; but I am getting wiser every day—recollecting Galileo, and the times when philosophers and public benefactors were burnt for their services." In another letter he alludes to the sycophancy of a chemical journal, which, after the grossest abuse, suddenly turned round, and disgusted him with its adulation. "I never shake hands," says he, "with chimney sweepers, even when in their May-day clothes, and when they call me 'Your honour.'"
While the trials above related were proceeding in the ports of England, the naval department of France was prosecuting a similar enquiry; and as experiments of this nature are conducted with greater care, and examined with superior science, in that country, it may not be uninteresting to the English reader to receive a detail of the examination of the bottom of La Constance frigate, in which the protectors bore a much larger proportion to the copper surface than was ever practised in the British navy. This document, I may observe, is now published for the first time.
"The inspection of the bottom of the frigate La Constance, has given rise to some interesting observations on the effect of protectors, and it has confirmed the fact before advanced of the great inconvenience which attends the application of too large a proportion of the protecting metal.
"The surface of this metal, which was of cast iron, placed on each side of the keel, and in long scarphs of iron plates situated towards the stem andstern-post and the water line, appeared to have been about the 1-30th part of the surface of the copper, instead of the 1-250th part as now practised.
"The galvanic action has been extreme, both in rapidity and intensity. The scarphs are entirely destroyed, and have absolutely disappeared; and we should have been ignorant of their having ever existed, had we not been informed of the fact, and observed dark stains which marked their position, and discovered the nails still entire by which they had been fastened.
"The plates, which were in the first instance about three inches thick, were covered throughout their whole length by a thick, unequal coating, spotted with yellow oxide. This was principally owing to the absorption of about twenty-five per cent. of its weight of water. Under this, the iron was as soft as plumbago, and there remained scarcely an inch of metal of its original metallic hardness.
"The bulky and irregular appendage (the protectors) at the lower part of the ship's bottom caused a great noise in the sea, in consequence of the dead water which it occasioned, and doubtless lessened the speed of the vessel. But that which contributed most to this unfortunate result, was the exceedingly unclean state of the copper, arising from the excess of the iron employed: this, carried to so great an extent, having the effect of extracting matter from the water, which, forming a concretion on the sheets, enabled the marine animals the more easily to attach themselves. The sheathing was covered with a multitude oflepas anatifera, shells with five valves, suspended by a pedicle of three or four centimetreslong, collected into groups; oflepas tintinnabulum, a shell with six valves; of oysters withopercula; ofpolypi, &c. No part of the bottom was free from them.
"Below, the copper was certainly preserved from oxidation; and up to within a few sheets of the water line, it did not appear to be worn. But to save expense, it was obliged to be cleansed without removal, by rubbing it hard with bricks and wet sand, which has succeeded very well in restoring its copper colour."
The following is the description of shells above enumerated:—
GenusAnatifa, Encyclopedia.—(Lepas, Linnæus.)
Fig. 1.SmoothAnatifa(Lepas anatifera, Linn.)—Shell consisting of five valves, of which two larger and two smaller ones are opposite to each other; and a fifth, which is narrow, is arched and rests upon the ends of the first four: these valves are not connected by any hinge; they are held together by the skin of the animal, which lines their interior and opens in front by a longitudinal separation. Their colour is orange during the life of the animal. The base of the shell is united to a fleshy tube, tendinous, cylindrical, susceptible of contraction, saffron-coloured, becoming brown and black in drying.
Fig. 2.SmoothAnatifa, as seen from the other side, the pedicle dry and contracted.
Fig. 3.SmoothAnatifa, as seen in front, showing the longitudinal separation.
GenusAnomia.
Shell with valves, unequal, irregular, having an operculum; adhering by its operculum; valve usually pierced, flattened, having a cavity in the upper part;the other valve a little larger, concave, entire; operculum small, elliptical, bony, fixed on some foreign body, and to which the interior muscle of the animal is attached.
Species, Onion-peelAnomia.—(Ephippium, Linn.)
Shell common, whitish and yellowish, found in the Mediterranean and the ocean.
Besides the abovementioned species, which were found in large quantities, there were also some muscles and oysters.—(Mytilus afer. Baccina.—Linn. Gmel. 3358.)
Genus "Balane de Blainville."
(Balanite, Encyclopedia.—Lepas, Linn.)
Fig. 1.Tulip Balanus.—(Lepas tintinnabulum, Linn.)
Shell with six unequal valves articulated by a scaly suture, of which the edges appear to be finely crenellated in the cavity; the formof the valves is conical, aperture ample, and nearly quadrangular.
Operculum composed of four triangular pieces crenellated and marked with very projecting transverse striæ, which appear to extend from the top to the bottom; the two posterior pieces are perpendicular, and are applied to the hinder partition of the cavity of the shell; they are terminated by two conical prolongations, of which the points are sharp and diverging. The two foremost pieces are placed in the aperture, in an oblique direction. The colour of this balanus from clear red to violet and brown.
Fig. 2.View of the upper part of the Tulip Balanus.
Fig. 3.View of the base.
Genus Oyster, (Ostrea.)
Species of oyster, nearly similar to the common oyster, (Ostrea edulis,) and of the Huître cuilier, (Ostrea cochlear,) their shell rather fragile, almost without lamellæ; upper valve concave, colour rather deep violet, form variable.
"Besides these three kinds of Molluscæ, of which the number was considerable, several species of calcareous polypi were found; but those which could be obtained were too imperfect to allow of their being correctly described.
"The iron which was used to protect the copper on the bottom of the Constance frigate having been subjected to chemical analysis, the following are the results.
"This iron, which was in small fragments, very friable, little attracted by the loadstone, soft to the touch, and soiling the fingers like plumbago, gave out in rubbing it a very strong smell, very muchlike that of burnt linseed oil. Its colour on the exterior was a brownish yellow, and its interior a blackish grey, studded with little points extremely brilliant.
"A short time after they had been taken from the keel of the frigate, where they were covered with a layer of hydrated peroxide of iron, of six or eight lines in thickness, and been enclosed in a paper box, these fragments became strongly heated, and underwent a real combustion by means of the oxygen of the atmosphere; the combustion was accompanied by the production of a certain quantity of aqueous vapour.
"In order to ascertain whether this elevation of temperature was really alone owing to the absorption of the oxygen, a case containing twelvegrammesof this iron was placed under a receiver, which contained two hundred millimetres, inverted over a tube of mercury; and it was observed, in the course of an hour, that this air had diminished by forty millimetres, or one-fifth of its volume. Examining afterwards that which remained in the receiver, it was discovered that it had no effect whatever either on lime-water or the tincture oftournesol,—that it was not inflammable,—that it extinguished a candle; in a word, that it presented all the negative qualities of azotic gas, strongly infected with the smell before stated.
"It must be evident that the oxygen which was absorbed in this experiment was employed solely in burning the iron, which was already in a state ofprotoxide, as was indicated by its little degree ofcohesion, by the avidity with which it seized this principle, and by its dissolving in sulphuric acid, which operated without effervescence, and without disengaging hydrogen gas.
"Fivegrammesof this oxidized iron being reduced to an impalpable powder, and then made red-hot in a platina crucible, and mixed with three parts ofpotasse à l'alcool, were reduced to a clammy mass, coloured on its edges with a clear beautiful green, and with a greenish yellow on the other parts; which at once indicated the presence of a small portion of manganese, and that of a littlechrôme; metals which are found united in almost all sorts of iron. Treated in the usual way, this mass exhibited—
"First, Traces, scarcely sensible, of these two metals.
"Secondly, Onegrammeof brilliant black powder, soft to the touch, staining paper, insoluble in muriatic acid when applied boiling: it was therefore a true percarburet of iron.
"Thirdly, Threegrammesand tendecigrammesof peroxide of iron.
"On being subjected to the action of boiling water, five grammes of this pulverized iron gave out threedecigrammesof soluble matter, composed, for the greater part, ofhydrochlorateof iron, and a trace of hydrochlorate of magnesia, together with a little organic matter, the combination of which with the iron will account for the insufferable smell which it gave out when the iron was heated. This saline solution sensibly reddened the litmus paper: aneffect which was owing to the muriatic acid, which, in uniting with oxidized iron, and with most other metallic oxides, never forms combinations which are perfectly neutral, but which are always more or less acid.
"It has in vain been attempted to discover in this oxidized iron the presence of silex, of alumina, and of the sulphuric and carbonic acids, either free, or in combination.
"It results from this analysis, that the fragments of the protectors, which have been the object of it, are composed, in a hundred parts, of about
"As to the reddish yellow matter, with small protuberances like nipples, which formed a thick layer on the surface of the protectors, it was formed of 75 parts of oxide of iron at the most, and 25 parts of water, besides some atoms of hydrochlorate of iron, hydrochlorate of soda, and hydrochlorate of magnesia."
Had not the health of Davy unfortunately declined at the very period when his energies were most required, such is the unbounded confidencewhich all must feel in his unrivalled powers of vanquishing practical difficulties, and of removing the obstacles which so constantly thwart the applications of theory, that little doubt can be entertained but he would soon have discovered some plan by which the adhesion of marine bodies to the copper sheathing might have been prevented, and his principle of Voltaic protection thus rendered available. An experiment indeed, altogether founded upon this same principle, has been already proposed, and will be shortly tried in the British navy, by building a schooner, and fastening its materials together with copper bolts, and afterwards sheathing the bottom with thin plates of iron, which are to be protected by bands of zinc. At the same time, another schooner is to be built, in which the fastenings are to consist entirely of iron bolts and nails, the former to be protected by a zinc ring under each head or clench, and the latter to have a small piece of zinc soldered under its head.
This plan of protection was first adopted in America, at the recommendation of Dr. Revere; and upon its successful issue, that gentleman was lately induced to take out letters patent not only in England, but in all the maritime countries of Europe, for the sole right of manufacturing iron sheathing, bolts, and nails, thus protected.
As no doubt now exists as to the principle of the protection of iron by zinc, the bolts and nails may be expected to remain free from rust as long as the more oxidable metal lasts; but with regard to the success of the iron sheathing, it is impossible toentertain the same confidence; for what, in this case, is to prevent the adhesion of shell-fish and sea-weed upon its surface? Let it be remembered, that it is only when the copper is in the act of solution in sea-water that the sheathing remains clean. In the year 1829, the Tender to the Flagship at Plymouth had her copper on one side of the bottom painted with white lead: in six months, this side was covered with long weeds; while the other side, which had been left bright, and consequently exposed to the solvent action of the salt-water, was found entirely free from all such adhesions.
The failure of the Ship protectors a source of great vexation to Davy.—His Letters to Mr. Poole.—He becomes unwell.—He publishes his Discourses before the Royal Society.—Critical Remarks—and Quotations.—He goes abroad in search of health.—His Letter to Mr. Poole from Ravenna.—He resigns the Presidency of the Royal Society.—Mr. Gilbert electedpro tempore.—Davy returns to England, and visits his friend Mr. Poole.—Salmonia, or Days of Fly-fishing.—An Analysis of the Work, with various extracts to illustrate its character.
The friends of Sir Humphry Davy saw with extreme regret that the failure of his plan for protecting copper sheathing had produced in his mind a degree of disappointment and chagrin wholly inconsistent with the merits of the question; that while he became insensible to the voice of praise, every nerve was jarred by the slightest note of disapprobation. I apprehend, however, that the change of character which many ascribed to the mortification of wounded pride, ought in some measure to be referred to a declining state of bodily power, which had brought with it its usual infirmities of petulance and despondency. The letters I shall here introduce may perhaps be considered as indicating that instinctive desire for quiet and retirementwhich frequently marks a declining state of health, and they will be followed by others of a less equivocal character.
TO THOMAS POOLE, ESQ.Grosvenor Street, Nov. 24, 1824.MY DEAR POOLE,It is very long since I have heard from you, Mr. A——, whom you introduced to me, has sometimes given me news of you, and I have always heard of your health and well-being with pleasure.My immediate motive for writing to you now is somewhat, though not entirely selfish. You know 1 have always admired your neighbourhood, and I have lately seen a place advertised there, called, I think,——, not far from Quantock, and combining, as far as advertisement can be trusted, scenery, fishing, shooting, interest for money, &c.If it is not sold, pray give me a little idea of it; I have long been looking out for a purchase,—perhaps this may suit me. After all, it may be sold; if so, no harm is done.I go on labouring for utility, perhaps more than for glory; caring something for the judgment of my contemporaries, but more for that of posterity; and confiding with boldness in the solid judgment of Time.I have lately seen some magnificent country in the Scandinavian peninsula, where Nature, if not a kind, is at least a beautiful mother.—I wonder there have not been more poets in the North.I am, my dear Poole,Very affectionately your old friend,H. Davy.
TO THOMAS POOLE, ESQ.
Grosvenor Street, Nov. 24, 1824.
MY DEAR POOLE,
It is very long since I have heard from you, Mr. A——, whom you introduced to me, has sometimes given me news of you, and I have always heard of your health and well-being with pleasure.
My immediate motive for writing to you now is somewhat, though not entirely selfish. You know 1 have always admired your neighbourhood, and I have lately seen a place advertised there, called, I think,——, not far from Quantock, and combining, as far as advertisement can be trusted, scenery, fishing, shooting, interest for money, &c.
If it is not sold, pray give me a little idea of it; I have long been looking out for a purchase,—perhaps this may suit me. After all, it may be sold; if so, no harm is done.
I go on labouring for utility, perhaps more than for glory; caring something for the judgment of my contemporaries, but more for that of posterity; and confiding with boldness in the solid judgment of Time.
I have lately seen some magnificent country in the Scandinavian peninsula, where Nature, if not a kind, is at least a beautiful mother.—I wonder there have not been more poets in the North.
I am, my dear Poole,Very affectionately your old friend,H. Davy.
TO THE SAME.January 5, 1825.MY DEAR POOLE,My proposition to come into Somersetshire about the 10th was founded upon two visits which I had to pay in this county, Hants; I am now only about sixty miles from you; and had you been at home, I should have come on to Nether Stowey. The 13th is the first meeting of the Royal Society after the holidays; and though I might do my duty by deputy, yet I feel that this would not be right, and I will not have the honour of the chair without conscientiously taking the labours which its possession entails. I regret therefore that I cannot be with you next week. God bless you.Believe me always, my dear Poole,Your affectionate friend,H. Davy.
TO THE SAME.
January 5, 1825.
MY DEAR POOLE,
My proposition to come into Somersetshire about the 10th was founded upon two visits which I had to pay in this county, Hants; I am now only about sixty miles from you; and had you been at home, I should have come on to Nether Stowey. The 13th is the first meeting of the Royal Society after the holidays; and though I might do my duty by deputy, yet I feel that this would not be right, and I will not have the honour of the chair without conscientiously taking the labours which its possession entails. I regret therefore that I cannot be with you next week. God bless you.
Believe me always, my dear Poole,Your affectionate friend,H. Davy.
TO THE SAME.Park Street, Feb. 11, 1825.MY DEAR POOLE,I had a letter a few days ago from C——, who writes in good spirits, and who, being within a few miles of London, might, as far as his friends are concerned, be at John a Grot's house. He writes with all his ancient power. I had hoped that, as his mind became subdued, and his imagination less vivid, he might have been able to apply himself to persevere, and to give to the world some of those trains of thought, so original, so impressive, and at which we have so often wondered.I am writing this letter at a meeting of the Trustees of the British Museum, which will account forits want of correction. Lest I should be more desultory, I will conclude by subscribing myself, my dear Poole, your old and affectionate friend,H. Davy.
TO THE SAME.
Park Street, Feb. 11, 1825.
MY DEAR POOLE,
I had a letter a few days ago from C——, who writes in good spirits, and who, being within a few miles of London, might, as far as his friends are concerned, be at John a Grot's house. He writes with all his ancient power. I had hoped that, as his mind became subdued, and his imagination less vivid, he might have been able to apply himself to persevere, and to give to the world some of those trains of thought, so original, so impressive, and at which we have so often wondered.
I am writing this letter at a meeting of the Trustees of the British Museum, which will account forits want of correction. Lest I should be more desultory, I will conclude by subscribing myself, my dear Poole, your old and affectionate friend,
H. Davy.
TO THE SAME.Feb. 28, 1825.MY DEAR POOLE,I am very much obliged to you for your two letters, which I received in proper time. I have deferred writing, in the hopes that I might be able to pay you a visit and see the property, but I now find this will be impossible. I have a cold, which has taken a stronger and more inflammable character than usual, which obliges me to lay myself up; and in this weather it would be worse than imprudent to travel.I have seen Mr. Z——, and can perfectly re-echo your favourable sentiments respecting him. I saw the plan of the estate, and heard every thing he had to say respecting the value, real and imaginary, of the lands. He certainly hopes at this moment for a fancy price, and he is right if he can get it.I have less fancy for the place, from finding the trout-stream a brook in summer, where salmon-trout, or salmon, could not be propagated; for one of my favourite ideas in a country residence is varied and multiplied experiments on the increase and propagation of fish.What I should really like would be a place with a couple of hundred acres of productive land, and plenty of moor, a river running through it, and the sea before it; and not farther from London thanHampshire—a day's journey. There are such places along the coast, though perhaps in my lifetime they will not be disposed of. I should also like to be within a few miles of you; for it is one of the regrets in the life which I lead, that devotion to the cause of science separates me very much from friends that I shall ever venerate and esteem. God bless you, my dear Poole,Very affectionately yours,H. Davy.
TO THE SAME.
Feb. 28, 1825.
MY DEAR POOLE,
I am very much obliged to you for your two letters, which I received in proper time. I have deferred writing, in the hopes that I might be able to pay you a visit and see the property, but I now find this will be impossible. I have a cold, which has taken a stronger and more inflammable character than usual, which obliges me to lay myself up; and in this weather it would be worse than imprudent to travel.
I have seen Mr. Z——, and can perfectly re-echo your favourable sentiments respecting him. I saw the plan of the estate, and heard every thing he had to say respecting the value, real and imaginary, of the lands. He certainly hopes at this moment for a fancy price, and he is right if he can get it.
I have less fancy for the place, from finding the trout-stream a brook in summer, where salmon-trout, or salmon, could not be propagated; for one of my favourite ideas in a country residence is varied and multiplied experiments on the increase and propagation of fish.
What I should really like would be a place with a couple of hundred acres of productive land, and plenty of moor, a river running through it, and the sea before it; and not farther from London thanHampshire—a day's journey. There are such places along the coast, though perhaps in my lifetime they will not be disposed of. I should also like to be within a few miles of you; for it is one of the regrets in the life which I lead, that devotion to the cause of science separates me very much from friends that I shall ever venerate and esteem. God bless you, my dear Poole,
Very affectionately yours,H. Davy.
TO THE SAME.Pixton near Dulverton, Nov. 1, 1826.MY DEAR POOLE,I cannot be in your neighbourhood, without doing my best to see you; and it is my intention to come to Stowey on Sunday. I hope I shall find you at home, and quite well.Mr. T——, who is here, gives me a very good account of you, which I trust I shall be personally able to verify.If you are at leisure, I will try to shoot a few woodcocks on Monday on the Quantock hills; on Tuesday I must go east.I have not been well lately. I cannot take the exercise which twenty years ago I went lightly and agreeably through. Will you have the kindness to hire a pony for me, that I may ride to your hills?I am sorry I did not know of your journey to Ireland and Scotland. I was in both those countries at the time you visited them, and should have been delighted to have met you.Do not write to me; for, even if you should notbe at home, Stowey is not more than ten or twelve miles out of my way; but I hope I shall find you.I am, my dear Poole,Your old and sincere friend,H. Davy.
TO THE SAME.
Pixton near Dulverton, Nov. 1, 1826.
MY DEAR POOLE,
I cannot be in your neighbourhood, without doing my best to see you; and it is my intention to come to Stowey on Sunday. I hope I shall find you at home, and quite well.
Mr. T——, who is here, gives me a very good account of you, which I trust I shall be personally able to verify.
If you are at leisure, I will try to shoot a few woodcocks on Monday on the Quantock hills; on Tuesday I must go east.
I have not been well lately. I cannot take the exercise which twenty years ago I went lightly and agreeably through. Will you have the kindness to hire a pony for me, that I may ride to your hills?
I am sorry I did not know of your journey to Ireland and Scotland. I was in both those countries at the time you visited them, and should have been delighted to have met you.
Do not write to me; for, even if you should notbe at home, Stowey is not more than ten or twelve miles out of my way; but I hope I shall find you.
I am, my dear Poole,Your old and sincere friend,H. Davy.
The complaints, as to the loss of his strength, which are expressed in the preceding letter, were but too well founded. Mr. Poole informs me that, during this visit in 1826, it was affecting to observe the efforts he made to continue his field sports. From being unable to walk without fatigue, he was compelled to have a pony to take him to the field, from which he dismounted only on the certainty of immediate sport.
On his return to London, his indisposition increased: he complained to me of palpitation of the heart, and of an affection in the trachea, which led him to fear that he might be suffering under the disease of which his father died.
The fatigue attendant upon the duties of the anniversary of the Royal Society (November 30th) completely exhausted him; and after his re-election as President, he was reluctantly obliged to retire, and to decline attending the usual dinner upon that occasion.
In January 1827, Sir Humphry Davy published the Discourses which he had delivered before the Royal Society, at six successive anniversary meetings, on the award of the Royal and Copley medals. They were published in compliance with a resolution of a meeting of the Council, held on the 21st of December 1826.
The practice of delivering an annual oration before the Royal Society, on the occasion of presenting the medal upon Sir Godfrey Copley's donation, prevailed during the presidency of Sir John Pringle; it was, however, during a long interval discontinued, and only revived during the latter years of Sir Joseph Banks.
The discourse usually commenced with a short tribute of respect to the memory of those distinguished Fellows who had died since the preceding anniversary. It then proceeded to announce the choice of the Council in its award of the medals, enumerating the objects and merits of the several communications which had been honoured with so distinguished a mark of approbation, and stating the circumstances which had directed the judges in their decision.
Much has been said and written upon the inutility, and even upon the mischievous tendency of this practice; and great stress has been laid upon the vices inseparably connected, as it is asserted, with the style of composition to which it gives origin. It appears to me, however, that it is only against the meretricious execution, not against the temperate use of such discourses, that this charge can be fairly and consistently sustained; and in the chaste and yet powerful addresses of Davy, such an opinion will find its best sanction, and obtain its strongest support.
Does it follow, because praise, when unduly lavished upon the labours of the scientific dead, may create comparisons and preferences injurious to the living, that we are to stifle the noblest aspirations ofour nature, and become as cold and silent as the grave that encloses their remains? Does it follow, because an undisciplined ardour may have occasionally exaggerated the merits of our contemporaries, that we are henceforth to withhold from them a just tribute of applause at their discoveries—to forego the advantages which science must derive from a plan so well calculated to awaken the flagging attention, to infuse into stagnant research a renewed spirit of animation, and to encourage the industry of the labourer in the abstract regions of science, with prospects gleaming with sunshine, and luxuriant in the fruitfulness which is to reward him?
Such was the character, such the effect of Davy's discourses. They exhibit a great assemblage of diversified talents, and display the refined views he entertained with respect to the mutual relations which the different sciences maintain with each other; they evince, moreover, a great command of language, and a power to give exact expression to what his mind had conceived.
To these six Discourses is prefixed his Address upon taking the chair of the Royal Society for the first time; the subject of which is "The present state of that Body, and the Progress and Prospects of Science." Upon this occasion, he particularly adverts to the light which the different branches of science may reflect upon each other. "In pure Mathematics—though their nature, as a work of intellectual combination, framed by the highest efforts of human intelligence, renders them incapable of receiving aids from observations of externalphenomena, or the invention of new instruments, yet they are, at this moment, abundant in the promise of new applications; and many of the departments of philosophical enquiry which appeared formerly to bear no relation to quantity, weight, figure, or number, as I shall more particularly mention hereafter, are now brought under the dominion of that sublime science, which is, as it were, the animating principle of all the other sciences."
"In the theory of light and vision, the researches of Huygens, Newton, and Wollaston, have been followed by those of Malus; and the phenomena of polarization are constantly tending to new discoveries; and it is extremely probable that those beautiful results will lead to a more profound knowledge than has hitherto been obtained, concerning the intimate constitution of bodies, and establish a near connexion between mechanical and chemical philosophy."
"The subject of heat, so nearly allied to that of light, has lately afforded a rich harvest of discovery; yet it is fertile in unexplored phenomena. The question of the materiality of heat will probably be solved at the same time as that of the undulating hypothesis of light, if, indeed, the human mind should ever be capable of understanding the causes of these mysterious phenomena. The applications of the doctrine of heat to the atomic or corpuscular philosophy of chemistry abound in new views, and probably at no very distant period these views will assume a precise mathematical form."
"In Electricity, the wonderful instrument of Volta has done more for the obscure parts of physicsand chemistry, than the microscope ever effected for natural history, or even the telescope for astronomy. After presenting to us the most extraordinary and unexpected results in chemical analysis, it is now throwing a new light upon magnetism.
'Suppeditatque novo confestim lumine lumen.'
"I must congratulate the Society on the rapid progress made in the theory of definite proportions, since it was advanced in a distinct form by the ingenuity of Mr. Dalton. I congratulate the Society on the promise it affords of solving the recondite changes, owing to motions of the particles of matter, by laws depending upon their weight, number, and figure, and which will be probably found as simple in their origin, and as harmonious in their relations, as those which direct the motions of the heavenly bodies, and produce the beauty and order of the celestial systems.
"The crystallizations, or regular forms of inorganic matter, are intimately connected with definite proportions, and depend upon the nature of the combinations of the elementary particles; and both the laws of electrical polarity, and the polarization of light, seem related to these phenomena. As to the origin of the primary arrangement of the crystalline matter of the globe, various hypotheses have been applied, and the question is still agitated, and is perhaps above the present state of our knowledge; but there are two principal facts which present analogies on the subject,—one, that the form of the earth is that which would result, supposing it to have been originally fluid; and the other, thatin lavas, masses decidedly of igneous origin, crystalline substances, similar to those belonging to the primary rocks, are found in abundance."
It is the privilege of genius to be in advance of the age, and to see, "as by refraction, the light, as yet below the horizon." It is with such a feeling that I have introduced the foregoing extracts, which I cannot but regard as prophetic of future discoveries.
The first discourse was delivered on the 30th of November 1821, on the occasion of announcing the award of two medals, on Sir Godfrey Copley's donation; one to J. F. W. Herschel, Esq. for his various papers on mathematical and physico-mathematical subjects; and the other, to Captain Edward Sabine, R.A., for his papers containing an account of his various experiments and observations made during a voyage and expedition in the Arctic regions.
As I am desirous that the reader should be made acquainted with the nature and style of the address with which he accompanied the presentation of the medal, I cannot select a happier example, or one in the sentiments of which every person will more readily participate, than the following:—