94 MK. F. C. CALVERT ON THE SOLUBILITY OF 



produce any alteration in the results obtained. During this 

 series of experiments, I determined the solubility of nitrate of 

 baryta in nitric acid sp. gr. 1.167 at a temperature of- 60°. 

 1 grain of nitrate of baryta requires 250.2 

 2.5 „ „ „ 446.8 



5.0 „ „ „ 933.8 



6.5 „ „ „ 1334 



8.0 „ „ „ 2800 



10.0 „ „ „ 3267 



ON THE INFLUENCE EXERCISED BY DIFFERENT DEGREES OF 

 CONCENTRATION OF NITRIC ACID ON THE FORMATION OF 

 SULPHATE OF BARYTA. 



In the following series of experiments I operated in an 

 entirely different manner; the same quantity of nitric acid, 

 sp. gr. 1.305, was put into each jar, and to each was added 

 multiple volumes of water ; therefore, each solution decreased 

 in density; and after having dissolved the quantity of sul- 

 phate of potash which I intended to employ, I poured in the 

 solution of nitrate of baryta. 



On comparing the experiments contained in the following 

 table, it will be seen that I have obtained results very different 

 from the preceding, for instead of 4.46 of sulphate of baryta 

 remaining in solution in the last five jars, as was the case 

 when I employed the same quantities of salt in multiple 

 volumes of the same acid, precipitates were found in all the 

 jars, and that in the space of three minutes ; therefore, mul- 

 tiple volumes of acid, decreasing in strength, do not exert the 

 same influence as the increase of volume of the same acid. 

 This table also presents a fact important for chemical analysis, 

 viz., that the solubility of sulphate of baryta is affected even 

 by the weakest acid, since 2200 grs. of nitric acid, sp. gr. 

 1.032, are capable of dissolving 0.08 of sulphate of baryta; 

 this solubility, though slight, is still five times greater than it 

 would be in distilled water. 



