3<>4 



Frederick Guthrie on Salt Solution* 



at 0° C. contained 5*7990 of KI, or 55*93 per cent., and since 

 Kremers found 55*86, I have adapted his determination for 

 the 20° and 40° temperatures by adding 0*1 per cent, to his 

 results. The ascent of the tracing (fig. 1) between the cryo- 

 hydrate and 0° is too abrupt for the insertion of any interme- 

 diate value which shall be trustworthy. 



§ 134. Separation of Ice and Anhydrous Sulphate of Ammo- 

 nium from solutions of that salt. — The salt was dried at about 

 100° C, finely powdered, kept at 100° C. for ten hours, and 

 kept for three days and nights in an exhausted receiver over 

 sulphuric acid. 



Table XXIII. 



(NH 4 ),SO, 



per cent, by 



weight. 



H 2 



per cent, by 

 weight. 



Temperature 

 Centigrade at 

 which solidifi- 

 cation begins. 



i 



Nature of 

 solid formed. 



10 



90 



o 



- 2-6 



Ice. 



20 



80 



- 6 



it 



28-6 



714 



-10-8 



>5 



40 



60 



-160 





417 



583 



-17 



Cry ohyd rate. 



41 9 



581 



00 



(NH 4 ) a S0 4 . 



(H.S.) 43-2 



56-8 



4-190 



»> 



I have for the temperature 19° adopted H. Schiff's deter- 

 mination. Of all the salts which I have examined, the sul- 

 phate of ammonium shows in its tracing the greatest precipi- 

 tousness in its ascent from the cryohydrate to the 0° 0. ratio. 

 It is in this region undoubtedly very nearly a straight line. 

 The solubility at 0° 0. was found from the data, 13*2512 of 

 the solution gave 5*5522 of the salt obtained anhydrous by the 

 means mentioned above. 



§ 135. Separation of Ice or Nitrate of Ammonium from solu- 

 tions of that salt. — The nitrate of ammonium used was dried at 

 100° C.j finely crushed, and heated to incipient fusion ; it 

 ceased to lose weight but showed no trace of the nitrite. In 

 the determination of the solubility at 0° C. it was treated in 

 the same manner. 



