67 



urea solution, and a brisk evolution of gas ensues. The de- 

 composition is assisted towards the end by plunging the lower 

 end of the apparatus into hot water. The nitrogen evolved 

 contains a small quantity of oxygen, which is determined in tl>e 

 usual way by transferring the gases over mercury and absorbing 

 the oxygen with an alkaline solution of pyrogallol. The presence 

 of sugar renders the evolution of nitrogen more complete. 



212. Urinometer ; set of apparatus for the use of 

 medical men, consisting of mahogany stand with drawer 

 and draining pegs for test-tubes. Six narrow-mouth 

 stoppered bottles. Price II. 5s. 



1886. Exhibited by Townson $ Mercer. 



213. Urinometer. Set of apparatus for travelling ; in 

 stout japanned tin case, with lock and key. Dimensions, 

 8 in. by 6 in. by 3| in. Price 11 10s. 



1886. Exhibited by Townson fy Mercer. 



214. Urinometer test-tubes (2), Veale's and Esbach's. 

 Prices Is. and 2s. 6d. 



1886. Exhibited by Townson fy Mercer. 



215. Model of spongy iron filter, with filtering 

 materials employed. 



1876. Exhibited by Gustav Bischof. 



