1813.] Account of a compound Salto 369 



is accidental J but with regard to the muriate of lead, I am 

 inclined to suppose it a necessary constituent of the salt, from 

 observing the uniform quantity in which it is produced, however 

 regular in their sliape and transparent the crystals may be. From 

 the peculiar nature of the salt, it is difficult to verify this con- 

 jecture by experiment; the affinities which its constituents exert 

 on each other are so easily disturbed, that solution in water is 

 sufficient to cause their separation : when acid solvents are used 

 the same effect is produced ; in all cases the muriate of lead is 

 rather decomposed, or precipitated in a half crystallized state^ 

 sulphate of soda crystallizes uncombined, in a quantity which 

 exceeds in weight the whole of the salt dissolved, and muriate 

 of manganese remains in the mother water. I have not suc- 

 ceeded in any instance in reproducing the compound. 



Until more successful experiments enable us to decide upon 

 tliis subject with a greater degree of certainty, it may perhaps 

 be better to consider the muriate of lead a necessary part of the 

 salt, and the uncombined manganese to be accidentally present : 

 100 parts of it, then, are composed of very nearly 



55*47 Sulphate of soda. 



26*79 Muriate of manganese. 



• 1-52 Muriate of lead. 



16-22 Water. 



100-00 



The action of the acid gases on the cover, and on the 

 agitator of the still, is the cause of the formation of the muriate 

 of lead ; but a difficulty still remained to be accounted for, as, 

 according to the received affinities, sulphate of soda and muriate 

 of lead are incapable of existing together in the same liquor. 

 The following are a few out of a number of experiments made 

 on the subject :■— 



1. Muriate of lead, boiled in a solution of sulphate of soda, 

 was converted into sulphate of lead ; and no crystals of the 

 muriate of lead were obtained on cooling the solution. 



2. Muriate of lead and sulphate of soda, boiled together in 

 diluted muriatic acid, were wholly dissolved, and yielded on 

 cooling crystals of muriate of lead j no sulphate of lead appeared 

 to be formed. 



3. Muriate of lead, boiled in sour liquor, was quickly dis- 

 solved, and crystallized abundantly on cooling. 



4. Sulphate of soda, muriate of manganese, and muriate of 

 lead, boiled together, yielded on cooling no crystals of muriate 

 of lead. 



5. Muriate of lead, boiled in diluted su'phuiic acid, was 



Vol. L N° V, 2 A - 



