66 



the volume read, also the temperature and barometric pressure at 

 the time. Each c.c. of gas, reduced to and 760 m.m. is equal 

 to 0-627 nig. N. 



206. Schwarz's nitrogen apparatus. Price 16s. 



1886. Exhibited by Townson fy Mercer. 



This is merely a convenient and portable modification of 

 Lunge's nitrometer, without india-rubber connexions. It is used 

 exactly in the same manner as the latter, with the advantage 

 of more conveniently producing levels by aid of the tap at the 

 bottom. 



207. Brady's nitrometer ; same principle as Lunge's 

 apparatus. Price 8s. 6d. 



1886. Exhibited by Townson fy Mercer. 



208. Crurn's nitrogen tube, used for the estimation of 

 nitrogen in the same way as Lunge's apparatus. Price 

 3s. 6d. 



1886. Exhibited by Townson Mercer. 



209. Knop's improved azotometer. 



E. 136. 1877. Made by F. Hugershoff, Leipsic. 



210. Staedel's apparatus for the collection of 

 nitrogen. Price II. 9s. 



1886. Exhibited by Townson If Mercer. 



The nitrogen nnd carbonic acid obtained by the combustion of 

 a nitrogenous body are led by means of the side tube into the bulb 

 immediately below the graduated measuring tube. This bulb 

 contains potash, and when all the C0 2 has been absorbed the 

 nitrogen is displaced upwards into the measuring tube, and its 

 volume read. 



211. Hiifner's apparatus for the estimation of urea. 

 Price 16s. 



1886. Exhibited by F. E. Seeker $ Co. 



A solution of sodium hypobroruite is used, which is made by 

 dissolving 100 grains of NaHO in 250 c.c. of water, and adding 

 25 c.c. of bromine when cold. The urea is dissolved and placed 

 in the lower part of the mixing apparatus and shut off from the 

 hypobromite solution by a large bore stopcock. The upper 

 portion of the mixing vessel is large enough to hold 100 c.c. of 

 hypobromite solution, with its own volume of water. The glass 

 cup is filled with a saturated solution of common salt, and the 

 measuring cylinder, filled with distilled water, is inverted in this, 

 and over the orifice of the mixing vessel. On turning the stop- 

 cock the specifically heavier hypcbromite mixes rapidly with the 



