2o8 abstracts: analytical chemistry 



the birds took up their nightly abode on the edge of the Capitol grounds. 

 The number of birds present at the Red Cross roost reached about 35,000 

 on August 9, but subsequently there was a gradual diminution. Smaller 

 numbers of Quiscalus quiscula quiscula, Sturnus vulgaris vulgaris, and 

 Riparia riparia riparia roosted at times with the martins or in their 

 immediate vicinity. H. C. O. 



ANALYTICAL CHEMISTRY.— r/i^ hydrochloric acid color method 

 jar determining iron. J. C. HosTETTER. Journ. Amer. Chem. 

 Soc, 41: 1531-1543. Oct., 1919. (Geophysical Lab. Papers on 

 Optical Glass, No. 17.) 



Conditions have been found under which the yellow color developed 

 by dissolving ferric iron in hydrochloric acid may be used for the de- 

 termination of iron. The temperature coefficient for this color varies 

 from 2 to 3 per cent per degree, depending on the concentration of iron 

 and probably also on the acidity. The color developed by a given 

 amount of iron varies with the acid concentration, reaching the maxi- 

 mum intensity at from 26 to 28 per cent HCl. The relative increase 

 produced by acid is greater the higher the concentration of iron; this 

 is especially true above 20 per cent HCl, but below this concentration 

 the relative change is independent of the iron content. Inasmuch as 

 solutions must frequently be boiled in order to insure the complete 

 solution of iron present as "scale," the use of constant-boiling acid is 

 recommended and its use has been found to be altogether satisfactory. 

 The effects of salts on the color indicate that sulfates cause bleaching 

 and chlorides intensification; detailed study of the effect of the very 

 soluble calcium chloride shows that an intensification of 2.5 may be 

 attained by the addition of this salt; consequently, when testing for 

 iron in a very soluble chloride the standard iron solution must be made 

 up to possess the same salt concentration. Some applications of the 

 method are given and some results are presented. J. C. H. 



ANALYTICAL CHEMISTRY.— A method for determimtion of the 

 volatile matter in oxides of lead. Olaf Andersen. Journ. Amer. 

 Ceram. Soc, 2: 782-783. Oct., 1919. (Geophysical Lab. Papers 

 on Optical Glass, No. 18.) 



The amount of volatile constituents in a sample of litharge or other 

 oxide of lead can be accurately determined by conversion of the PbO 

 into PbSiOs. The sample is mixed with a weighed quantity of silica, 



