164 MEMOIR OF DR. DALTON, AND 



" Therefore the relation of the hardest steel to the strongest 

 vitriol is 175 : 240. 



" Application of the doctrine of affinity of bodies,^ *' This 

 will best be shewn by examples. 



** Is it possible by Beguin's spirit of sulphur (a sulphide of 

 ammonium chiefly) to decompose the luna cornua, or to 

 separate the muriatic acid entirely without loss ?" 



" To settle this question we require only the following ex- 

 periments. Muriatic acid has a smaller degree of affinity with 

 silver than with the volatile salt. Sulphur, on the other hand, 

 unites with silver in preference to the volatile salt. The 

 silver is not separated from the muriatic acid by the volatile 

 salt, on account of accidental circumstances, but this separation 

 follows the moment any other body unites with the silver, if 

 it has not the property of dissolving the silver. But sulphur 

 is just such a body, and is^ therefore, fitted for the purpose. 

 If, then, the spirit of sulphur of Beguin is poured on finely 

 powdered luna cornua, it is easily seen that the muriatic acid 

 in the luna cornua must unite with the volatile salt in the 

 spirit of sulphur, and the sulphur will unite with the silver. 

 The new products that are formed by this separation, can 

 consequently be nothing more than common sal ammoniac and 

 sulphuretted silver. 



Page 452. '' Another similar question arises by which the 

 proportions of the mixture must be considered. How much 

 cinnabar must be mixed with the luna cornua, so as com- 

 pletely to separate the silver ? 



" The possibility of this decomposition may be shewn in 

 the same way as in the first case. If no particular experiment 

 is made, it depends on the comparison only of the following pro- 

 positions. Half an ounce of luna cornua contains ISOA grains 

 of fine silver. Half an ounce of fine silver takes up 35^ grains of 

 sulphur. We may then calculate that for I80t% grains of fine 

 silver, 26 1 grains of sulphur are required. We know besides, 



* Page 450. 



