NOTES.

NOTES.LECTURE I.1Page 13. The opening lecture was twice postponed on account of Dr. Faraday’s illness.2Page 22.Platinum, with one exception, the heaviest body known, is 21½ times heavier than water.3Page 22.Aluminiumis 2½ times heavier than water.4Pages 23 and 24.Power or Property in Water.—This power—the heat by which the water is kept in afluidstate—is said, under ordinary circumstances, to belatentorinsensible. When, however, the water changes its form, and, by uniting with the lime or sulphate of copper, becomessolid, the heat which retained it in a liquid state is evolved.5Page 23.Anhydrous Sulphate of Copper: sulphate of copper deprived of its water of crystallisation. To obtain it, the blue sulphate is calcined in an earthen crucible.6Page 29.Add a little liquid to the marble, and decompose it.—Marble is composed ofcarbonic acidandlime, and, in chemical language, is calledcarbonate of lime. When sulphuric acid is added to it, the carbonic acid is set free, and the sulphuric acid unites with the lime to form sulphate of lime.Carbonic acid, under ordinary circumstances, is a colourless invisible gas, about half as heavy again as air. Dr. Faraday first shewed that, under great pressure, it could be obtained in a liquid state. Thilorier, a French chemist, afterwards found that it could be solidified.LECTURE II.7Page 55.Crystallisation of Alum.—The solution must be saturated—that is, it must contain as much alum as can possibly be dissolved. In making the solution, it is best to add powdered alum to hot water as long as it dissolves; and when no more is taken up, allow the solution to stand a few minutes, and then pour it off from the dirt and undissolved alum.8Page 57.Red Precipitate of Biniodide of Mercury.—A little care is necessary to obtain this precipitate. The solution of potassium should be added to the solution of perchloride of mercury (corrosive sublimate) very gradually. The red precipitate which first falls is redissolved when the liquid is stirred: when a little more of the iodide of potassium is added, a pale, redprecipitate is formed, which, on the further addition of the iodide, changes into the brilliant scarlet biniodide of mercury. If too much iodide of potassium is added, the scarlet precipitate disappears, and a colourless solution is left.9Page 57.Paper Coated with Scarlet Biniodide of Mercury.—In order to fix the biniodide on paper, it must be mixed with a little weak gum water, and then spread over the paper, which must be dried without heat.Biniodide of Mercuryis said to bedimorphous; that is, is able to assume two different forms.10Page 59. “Prince Rupert’s Drops.”-These are made by pouring drops of melted green glass into cold water. They were not, as is commonly supposed, invented by Prince Rupert, but were first brought to England by him, in 1660. They excited a great deal of curiosity, and were considered “a kind of miracle in nature.”.11Page 60.Thick Glass Vessels.—They are calledProofsorBologna phials.12Page 61.Mica.—A silicate of alumina and magnesia. It has a bright metallic lustre—hence its name, frommico, to shine.13Page 62.Common salt, or chloride of sodium, crystallises in the form of solid cubes, which, aggregated together, form a mass, which may be broken up into the separate cubes.14Page 62.IcelandorCalc Spar.—Native carbonate of lime in its primitive crystalline form.LECTURE III.15Page 79.Solution of a Salt.—Acetate of soda. A solution saturated, or nearly so, at the boiling point, is necessary, and it must be allowed to cool, and remain at rest until the experiment is made.16Page 86.Binoxide of Nitrogen and Hypo-nitrous Acid.—Binoxide of nitrogen is formed when nitric acid and a little water are added to some copper turnings. It produces deep red fumes as soon as it comes in contact with the air, by combining with the oxygen of the latter to form hypo-nitrous acid.Binoxide of nitrogenis composed of two parts oxygen and one part of nitrogen;hypo-nitrous acidis composed of one part of nitrogen and three parts of oxygen.LECTURE IV.17Page 106.Chlorate of Potash and Sulphuret of Antimony.—Great care must be taken in mixing these substances, as the mixture is dangerously explosive. They must be powdered separately, and mixed together with a feather on a sheet of paper, or by passing them several times through a small sieve.18Page 107. The mixture of chlorate of potash and sugar does not require the same precautions. They maybe rubbed together in a pestle and mortar without fear. One part of chlorate of potash and three parts of sugar will answer. The mixture need only be touched with a glass rod dipped in oil of vitriol.19Page 107.Two Salts Dissolved in Water.—Sulphate of soda and chloride of calcium. The solutions must be saturated for the experiment to succeed well.20Page 111.Lead Pyrophorous.—This is a tartrate of lead which has been heated in a glass tube to dull redness as long as vapours are emitted. As soon as they cease to be evolved, the end of the tube is sealed, and it is allowed to cool.21Page 115.Gun-Cottonis made by immersing cotton-wool in a mixture of sulphuric acid and the strongest nitric acid, or of sulphuric acid and nitrate of potash.22Page 115.Paper Prepared like Gun-Cotton.—It should be bibulous paper, and must be soaked for ten minutes in a mixture of ten parts by measure of oil of vitriol with five parts of strong fuming nitric acid. The paper must afterwards be thoroughly washed with warm distilled water, and then carefully dried at a gentle heat. The paper is then saturated with chlorate of strontia, or chlorate of baryta, or nitrate of copper, by immersion in a warm solution of these salts. (SeeChemical News, Vol. I., page 36.)LECTURE VI.23Page 162.Sulpho-indigotic Acid.—A mixture of one part of indigo and fifteen parts of concentrated oil of vitriol. It is bleached on the side at which hydrogen gas is evolved, in consequence of the liberated hydrogen withdrawing oxygen from the indigo, thereby forming a colourless deoxidised indigo. In making the experiment, only enough of the sulpho-indigotic acid must be added to give the water a decided blue colour.24Page 164.Lead Tree.—To make a lead tree, pass a bundle of brass wires through the cork of a bottle, and fasten a plate of zinc round them just as they issue from the cork, so that the zinc may be in contact with every one of the wires. Make the wires to diverge so as to form a sort of cone, and having filled the bottle quite full of a solution of sugar of lead, insert the wires and cork, and seal it down, so as to perfectly exclude the air. In a short time the metallic lead will begin to crystallise around the divergent wires, and form a beautiful object.THE END.BELL AND BAIN, LIMITED, PRINTERS, GLASGOW.

LECTURE I.

1Page 13. The opening lecture was twice postponed on account of Dr. Faraday’s illness.

2Page 22.Platinum, with one exception, the heaviest body known, is 21½ times heavier than water.

3Page 22.Aluminiumis 2½ times heavier than water.

4Pages 23 and 24.Power or Property in Water.—This power—the heat by which the water is kept in afluidstate—is said, under ordinary circumstances, to belatentorinsensible. When, however, the water changes its form, and, by uniting with the lime or sulphate of copper, becomessolid, the heat which retained it in a liquid state is evolved.

5Page 23.Anhydrous Sulphate of Copper: sulphate of copper deprived of its water of crystallisation. To obtain it, the blue sulphate is calcined in an earthen crucible.

6Page 29.Add a little liquid to the marble, and decompose it.—Marble is composed ofcarbonic acidandlime, and, in chemical language, is calledcarbonate of lime. When sulphuric acid is added to it, the carbonic acid is set free, and the sulphuric acid unites with the lime to form sulphate of lime.Carbonic acid, under ordinary circumstances, is a colourless invisible gas, about half as heavy again as air. Dr. Faraday first shewed that, under great pressure, it could be obtained in a liquid state. Thilorier, a French chemist, afterwards found that it could be solidified.

Carbonic acid, under ordinary circumstances, is a colourless invisible gas, about half as heavy again as air. Dr. Faraday first shewed that, under great pressure, it could be obtained in a liquid state. Thilorier, a French chemist, afterwards found that it could be solidified.

LECTURE II.

7Page 55.Crystallisation of Alum.—The solution must be saturated—that is, it must contain as much alum as can possibly be dissolved. In making the solution, it is best to add powdered alum to hot water as long as it dissolves; and when no more is taken up, allow the solution to stand a few minutes, and then pour it off from the dirt and undissolved alum.

8Page 57.Red Precipitate of Biniodide of Mercury.—A little care is necessary to obtain this precipitate. The solution of potassium should be added to the solution of perchloride of mercury (corrosive sublimate) very gradually. The red precipitate which first falls is redissolved when the liquid is stirred: when a little more of the iodide of potassium is added, a pale, redprecipitate is formed, which, on the further addition of the iodide, changes into the brilliant scarlet biniodide of mercury. If too much iodide of potassium is added, the scarlet precipitate disappears, and a colourless solution is left.

9Page 57.Paper Coated with Scarlet Biniodide of Mercury.—In order to fix the biniodide on paper, it must be mixed with a little weak gum water, and then spread over the paper, which must be dried without heat.Biniodide of Mercuryis said to bedimorphous; that is, is able to assume two different forms.

Biniodide of Mercuryis said to bedimorphous; that is, is able to assume two different forms.

10Page 59. “Prince Rupert’s Drops.”-These are made by pouring drops of melted green glass into cold water. They were not, as is commonly supposed, invented by Prince Rupert, but were first brought to England by him, in 1660. They excited a great deal of curiosity, and were considered “a kind of miracle in nature.”.

11Page 60.Thick Glass Vessels.—They are calledProofsorBologna phials.

12Page 61.Mica.—A silicate of alumina and magnesia. It has a bright metallic lustre—hence its name, frommico, to shine.

13Page 62.Common salt, or chloride of sodium, crystallises in the form of solid cubes, which, aggregated together, form a mass, which may be broken up into the separate cubes.

14Page 62.IcelandorCalc Spar.—Native carbonate of lime in its primitive crystalline form.

LECTURE III.

15Page 79.Solution of a Salt.—Acetate of soda. A solution saturated, or nearly so, at the boiling point, is necessary, and it must be allowed to cool, and remain at rest until the experiment is made.

16Page 86.Binoxide of Nitrogen and Hypo-nitrous Acid.—Binoxide of nitrogen is formed when nitric acid and a little water are added to some copper turnings. It produces deep red fumes as soon as it comes in contact with the air, by combining with the oxygen of the latter to form hypo-nitrous acid.Binoxide of nitrogenis composed of two parts oxygen and one part of nitrogen;hypo-nitrous acidis composed of one part of nitrogen and three parts of oxygen.

LECTURE IV.

17Page 106.Chlorate of Potash and Sulphuret of Antimony.—Great care must be taken in mixing these substances, as the mixture is dangerously explosive. They must be powdered separately, and mixed together with a feather on a sheet of paper, or by passing them several times through a small sieve.

18Page 107. The mixture of chlorate of potash and sugar does not require the same precautions. They maybe rubbed together in a pestle and mortar without fear. One part of chlorate of potash and three parts of sugar will answer. The mixture need only be touched with a glass rod dipped in oil of vitriol.

19Page 107.Two Salts Dissolved in Water.—Sulphate of soda and chloride of calcium. The solutions must be saturated for the experiment to succeed well.

20Page 111.Lead Pyrophorous.—This is a tartrate of lead which has been heated in a glass tube to dull redness as long as vapours are emitted. As soon as they cease to be evolved, the end of the tube is sealed, and it is allowed to cool.

21Page 115.Gun-Cottonis made by immersing cotton-wool in a mixture of sulphuric acid and the strongest nitric acid, or of sulphuric acid and nitrate of potash.

22Page 115.Paper Prepared like Gun-Cotton.—It should be bibulous paper, and must be soaked for ten minutes in a mixture of ten parts by measure of oil of vitriol with five parts of strong fuming nitric acid. The paper must afterwards be thoroughly washed with warm distilled water, and then carefully dried at a gentle heat. The paper is then saturated with chlorate of strontia, or chlorate of baryta, or nitrate of copper, by immersion in a warm solution of these salts. (SeeChemical News, Vol. I., page 36.)

LECTURE VI.

23Page 162.Sulpho-indigotic Acid.—A mixture of one part of indigo and fifteen parts of concentrated oil of vitriol. It is bleached on the side at which hydrogen gas is evolved, in consequence of the liberated hydrogen withdrawing oxygen from the indigo, thereby forming a colourless deoxidised indigo. In making the experiment, only enough of the sulpho-indigotic acid must be added to give the water a decided blue colour.

24Page 164.Lead Tree.—To make a lead tree, pass a bundle of brass wires through the cork of a bottle, and fasten a plate of zinc round them just as they issue from the cork, so that the zinc may be in contact with every one of the wires. Make the wires to diverge so as to form a sort of cone, and having filled the bottle quite full of a solution of sugar of lead, insert the wires and cork, and seal it down, so as to perfectly exclude the air. In a short time the metallic lead will begin to crystallise around the divergent wires, and form a beautiful object.

THE END.

BELL AND BAIN, LIMITED, PRINTERS, GLASGOW.

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