40 ROYAL SOCIETY OF CANADA 



The product weighed 1309 grammes and at 8.79 per cent of nitro- 

 gen contained 106.27 grammes of that element. The 250 grammes of 

 vitriol used were capable of retaining only 71 grammes of nitrogen as 

 ammonia. The total nitrogen in 13635 grammes urine used amounted 

 to 111.8 grammes; consequently &ome of it must have been retained in 

 the condition of urea or of its sulphate. 



From these experiments it is plain that a complete recovery of tho 

 nitrogen in urea is quite possible if a certain quantity of acid is use! 

 and the water is expelled gradually by artificial heat. The following 

 experiment performed in an ordinary porcelain capsule furnishes addi- 

 tional proof of this: — 



III. 50 grammes of Welland Moss were moistened with a mixture 

 of 50 grammes oil of vitriol and 132 water. The addition of the 

 dilute acid left the moss comparatively dry, nor, on the further addition 

 of 160 grammes urine, was there any unabsorbed liquid on the bottom 

 of the capsule. The whole was then kept at a waterbath heat of 70° C 

 and urine added little by little, until its quantity amounted to ,1082 

 grammes. T^he drying was continued until the product was fit for 

 sampling when it weighed 178 grammes, and analysed as follows: — 



Total nitrogen 5.49 per cent. 



Nitrogen as free and saline ammonia . . . . 1.15 per cent. 



Total phosphoric acid 3.84 per cent. 



Potash 8.50 per cent. 



Ash 11.56 per cent. 



Moisture 33.76 per cent. 



The materials used in this experiment were: — 



Grammes Nitrogen 

 50 grammes Oil of Vitriol • • • • 



50 granunes of Welland Moss with 1.56 per cent N. 0.78 

 1082 grammes Urine with 0.83 per cent N 8.98 



Total 9.76 



The product weighing 178 grammes contained 5.49 per cent nitro- 

 gen or 9.77 grammes which accounted for the nitrogen used. Only 20.9 

 per cent of the latter was present as free and combined ammonia from 

 which it appears that the acid combines with some of the urea and pre- 

 vents its decomposition. 



Having ascertained that the use of sulphuric acid and artificial heat 

 were completely effective in retaining the nitrogen of urine, it became 



