FOOTNOTES:
[113] If the dishes show a manganese stain, wash them out with a few drops of hydrochloric and sulphurous acids. Pass the acid liquor through the same small filter but collect the liquor apart. Make ammoniacal and again pass through the filter, this time collecting the liquid with the main filtrate.
[114] This rarely amounts to more than 1 milligram.
[115] To make this, dissolve 1 gram of titanium oxide by fusing for some time with an excess of bisulphate of potash and dissolve out with cold water and sulphuric acid. Dilute to 1 litre, having previously added not less than 50 c.c. of strong sulphuric acid: 1 c.c. will contain .01 gram of TiO2. For the assay take 10 c.c. of this, add 2 c.c. of peroxide of hydrogen and dilute to 100 c.c. Run this from a burette into the flask until the colour equals that of the assay. Each c.c. equals 1 milligram of TiO2. Fluorides must be absent.
[116] C + O2 = CO2
[117] For example, soluble organic acids formed by partial oxidation with nitric acid.
[118] For coals, and other bodies containing sulphur, chromate of lead should be used instead of oxide of copper; and the temperature should be limited to dull redness.
[119] This may be prepared by dissolving 534 grams of ammonium chloride and 854 grams of crystallized cupric chloride (CuCl2.2H2O) in hot water and crystallizing.
[120] Soda-lime is made by dissolving 100 grams of "soda" in water, and carefully slaking 200 grams of lime with it. Evaporate to dryness in an iron dish and ignite at a low red heat in a crucible. Use the small lumps.
[121] Made by diluting 1 part by measure of saturated lime-water up to 10 with recently boiled distilled water.
[122] See under Gasometric Assays.
[123] See "A Method for the Separation and Estimation of Boric Acid," by F.A. Gooch, Chemical News, January 7, 1887.