168 Mr. Prideaux on the Atomic Weight 



it would go, — a method by which definite proportions were not 

 likely to be attained. It is to be remarked, however, that the 

 nitric and sulphuric solutions thus made are decomposed by 

 water into " sub-" and " bi-" salts : that red oxide is produced 

 by the decomposition of sulphuric acid ; and that silver and 

 mercury yield analogous compounds by the action of nitric 

 acid and alcohol, in which the former metal is in the state of 

 protoxide, the latter of red oxide. These facts lead to the in- 

 ference, that I'ed oxide is the oxide of 1 atom of each ingre- 

 dient; that the " super" sulphate and " super" nitrate are de- 

 ficient in acid ; and the *' bi-" salts compounds of one atom 

 acid and one oxide. The property of reddening vegetable 

 blues belongs to the salts of copper and some others, as well 

 as to these. 



The following experiments were conducted upon the sup- 

 position that 17 represents the atom of corrosive sublimate, 



consisting of Mercury 12"5 



Chlorine 4*5 



1st. — The " bi-" sulphate is familiar to chemists, but I was 

 disposed to obtain it by double decomposition. Solutions be- 

 ing made in distilled water of 17 grains corrosive sublimate, 

 and 1 5f grains crystallized sulphate of copper, were mixed hot 

 and set to crystallize. Solutions also of 17 grains sublimate 

 and 20j grains crystallized sulphate of soda were mixed, and 

 gradually evaporated at about 200°. In both the muriate 

 of mercury crystallized out, in the latter contrary to my ex- 

 pectation ; and as no other unexceptionable method occurred 

 to me, and the salt was already known, this experiment was 

 abandoned. 



2nd. — Solutions of 17 grains corrosive sublimate and 21*5 

 grains crystallized nitrate of silver were mixed hot and well 

 shaken together; the chlorideof silver fell rapidly, and the clear 

 liquor reddened litmus paper. Alternately evaporated and set 

 aside, it refused to crystallize till reduced to dryness. 



3rd. — Solutions of 17 grains sublimate and 23f crystallized 

 acetate of lead were mixed warm. Muriate of lead subsided, 

 and the clear liquor smelt stronger of acetic acid, but did not 

 aifect test paper much more than the solution of acetate of 

 lead. Two of these mixtures were made : the first [a) evapo- 

 rated at about 200°, and occasionally set aside ; the other {b) 

 left to spontaneous evaporation in the warm air over the sand- 

 bath, (a) when reduced to about a drachm began to deposit 

 nacreous foUicules, striated as if fibrous; and the liquid dried 

 away in the course of the night, leaving slender rhombic prisms, 

 (i) began to crystallize whilst more than a drachm remained, 

 and was removed to a cold place, where some opaque white 



crystals 



