Assaying.
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strychnine less than 0 . 0 2 milligram could not be detected. T h a t is, the greatest source of error in the ordinary strychnine determinations lies i n incomplete extraction by chloroform. J, F. NORRIS, REVIEWER
The Volumetric Determination of the Nitro Group in Organic Compounds. BY S. W. YOUNGAND R.E. SWAIN./. A m . Chem. SOC., 19,812-814.-The authors show that a quantitative determination of the nitro groups in dinitrobenzene can be made by reduction with a standardized solution of stannous chloride and titrating the excess of the latter. T h e method has already been applied to a large number of nitro compounds by Limpricht (Ber. d. chem. Ges., 11, 35, 40). ASSAY I NG. H . 0 . HOFIAN, REVIEWER.
Fire-Assay for Lead. BY JOHN F. CANNON. Eng. &Fin./., 64, 604.-The assay is made as follows : Weigh out 5 grams of ore, place it in a 5-gram crucible containing 2 0 grams lead flux (16 parts sodium bicarbonate, 16 potassium carbonate, 8 glass borax, 5 flour), mix, tap to settle the mixture, add eo grams of lead flux, tap, add 4-5 nails, place in a bright-red muffle, fuse in 20-25 minutes, close the muffle when the fusion has become quiet, heat to perfect fluidity, take out the crucible, remove the nails, tapping them to free them from adhering lead, tap the crucible and pour its contents on a level cast-iron plate, stringing out the slag to a thin thread, when even the smallest lead button will be found at the extreme end of the slag. Free the button from slag, hammer out thin on an anvil, and weigh. The Jones Coupe1 Moulder. BY THE PARKEAND LACYCo. Min. Sci. Press, 75, 357 ; Eng. Min.]., 64, 521.-This is a device by means of which the bone ash in the coupe1 mould is compacted by continuous and increasing pressure exerted by a system of levers and toggles worked by a foot-lever. Corrected Assays. BY E. H. MILLER. School Mines Quart., 19, 43-47 .-The author determined the losses in silver occurring with the niter and cyanide methods from assaying an argentiferous galena ore and a dry gold-bearing silver ore, containing some malachite. H e found that with the cyanide method silver is carried off in the slags, which is not fully recovered by re-treatment.
