Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: APPENDIX TO LECTURE I. A (p. S).—Two sealed glass tubes were exhibited both containing a portion of the same saturated solution of sulphur in carbon disulphide. One tube had been exposed to light for a week or two and contained a deposit of crystalline sulphur incrusting the side of the glass, while the other, which had been kept in the dark, was perfectly clear. B (p. 9).—For details concerning the experimental illustration of the explosion of hydrogen and chlorine under the influence of light see Roscoe and Schorlemmer,s Treatise on Chemistry, vol. i. p. 125. C (p. n).—Chlorine is passed through a flask containing boiling water and the mixed gas and water vapour passed though a porcelain tube strongly heated in a gas combustion furnace. The escaping gas is received over dilute caustic sodasolution to absorb excess of chlorine, and shown to be oxygen by the usual tests. D (P- !3)-—A solution of ferric chloride is divided into two portions, to one of which sulphurous acid or an aqueous solution of a sulphite is added. The two beakers are placed side by side on white paper and a few drops of potassium ferricyanide solution allowed to fall into each, the beaker containing the reduced iron salt giving a blue precipitate and the unreduced solution a brown colouration. E (p. 14).—A solution of ferric chloride in alcohol (methylated spirit answers the purpose) is divided into two portions in two large test tubes, one of which is placed on the table away from the influence of light and the other in a beaker of water (to keep it cool) and exposed for five or ten minutes to the electric beam from an arc lamp concentrated by means of a lens. After exposure the two tubes are placed side by side and ferricyanide added to each, when the solution in the exposed tube gives a deep ... --This text refers to an alternate Paperback edition.