. American chemical journal . is regionare many of the strongest lines of such metals as lead, cadmium,tin and indium ; and in a specimen of so called C. P. zinc severallines belonging to each of these metals were found on the nega-tives. With the zinc prepared by distillation in a vacuum, however,not a trace of any of the above impurities could be found. The rejected portions in A and C were also analysed, but wewere not able to find any impurities in them, except after the firstdistillation, when the contents of A were found to contain a smallamount of lead, and those of C a trace of cadmium
. American chemical journal . is regionare many of the strongest lines of such metals as lead, cadmium,tin and indium ; and in a specimen of so called C. P. zinc severallines belonging to each of these metals were found on the nega-tives. With the zinc prepared by distillation in a vacuum, however,not a trace of any of the above impurities could be found. The rejected portions in A and C were also analysed, but wewere not able to find any impurities in them, except after the firstdistillation, when the contents of A were found to contain a smallamount of lead, and those of C a trace of cadmium. II.— The Preparation of Pure Nitric Acid. It was found impossible by distilling from a platinum retort toprepare an acid which on evaporation would not leave a distillate contained in every case a small quantity of goldwhich the acid had extracted from the solder used in joining thetube to the body of the retort. We therefore made use of thefollowing simple arrangement, Fig. 2. Two platinum dishes, one Fig. 100 mm., the other 70 mm. wide, were arranged as shown in thefigure, the two being kept apart by hooks of thick platinum wirehung over the edge of the lower one. The upper one was cooledby putting into it pieces of ice. The acid, having first been treatedwith nitrate of silver, was then slowly distilled from a small flaskso placed that the vapors issuing from it would strike against andcondense upon the cold surface of the upper dish. The acid thusobtained left no residue on evaporation. It was preserved by Atomic Weight of Zinc. 315 placing the smaller dish in which it was collected under a bell transfer it from the dish to the crucible in which the zinc wasto be dissolved, a platinum spoon was used. III.— The Arrangement of Crucibles. Fig. 3 exhibits the arrangement of porcelain crucibles employedfor the conversion of the metal into oxide, i is a small crucible Fig. -x.
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherbalti, bookyear1879
