On the various forces of nature and their relations to each other. Faraday MichaelЧитать онлайн книгу.

1

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

2

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

3

Page 22. Aluminium is 2½ times heavier than water.

4

Pages 23 and 24. Power or Property in Water.– This power – the heat by which the water is kept in a fluid state – is said, under ordinary circumstances, to be latent or insensible. When, however, the water changes its form, and, by uniting with the lime or sulphate of copper, becomes solid, the heat which retained it in a liquid state is evolved.

5

Page 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.

6

Page 29. Add a little liquid to the marble, and decompose it.– Marble is composed of carbonic acid and lime, and, in chemical language, is called carbonate 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.

7

Page 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.