THE INORGANIC CONSTITUENTS OF URINE. 



89 



acetate in 100 cc. pure acetic acid, and dilute the mixture with 

 distilled water to 1000 cc. 



Potassium Ferrocyanide Solution. Dissolve 1 part of the salt 

 in 20 parts of water. 



Uranium Acetate Solution (1 cc. = -005 gramme H 3 PO 4 ). 

 Dissolve 20*3 grammes of pure uranium oxide in strong acetic 

 acid ; dilute with distilled water to a litre. 

 The strength of this solution must be ascer- 

 tained by means of a standard solution of 

 sodium phosphate. Or, dissolve 20*3 

 grammes uranium nitrate in strong acetic 

 acid, and dilute the solution to 1 litre. 



Apparatus Required. Mohr's burette, 

 fitted in a stand, and provided with a 

 Mohr's clip; piece of white porcelain: tripod 



B 

 O 



A 



Fig. 19. Burette Meniscus. 



Fig. 20. Erdmann's Float. 



stand and wire-gauze ; small beaker ; two pipettes, one to 

 deliver 50 cc. and the other for 5 cc. ; glass rod. 



13. Reading off the Burette. In the case of the burette being 

 filled with a watery fluid, note that the upper surface of the water 

 is concave. Always bring the eye to the level of the same hori- 

 zontal plane as the bottom of the meniscus curve. Fig. 19 

 shows how different readings may be obtained if the eye is 

 placed at different levels, A, B, C. 



