62 Analj/$es of Bi^oks^ [Jan. 



mercury into, peroxide, especially if heat be used ; and then the 

 loss which I nave described will ensue. It is quite requisite 

 that the acetate of potash should be pure; if it contain any sul- 

 phuric or muriatic salts, the protoxide of mercury will be thrown 

 down by them. The salt which I obtained was formed by using 

 acetate of soda, not finding the acetate of potash, usually met 

 with, sufficiently pure. Seventy-two parts of mercury yielded me 

 only 29 of acetate. Upon adding muriate of soda to the remain- 

 ing solution, I obtained some calomel, showing that the solution 

 should be evaporated for the further production of acetate. 

 After this, I obtained by the addition of soda a large quantity of 

 peroxide of mercury, as will be readily conceived when it is 

 observed that 72 parts of mercury gave only 29 of acetate. A 

 part of this loss I am inclined to attribute to the excess of nitric 

 acid already noticed. It appears to me that acetate of lead, but 

 I have not tried it, might be advantageously used instead of ace- 

 tate of potash. It must certainly be free from sulphuric and mu- 

 riatic salts. After what I have stated I think it is evident, first, 

 that less nitric acid should be used ; secondly, that less water 

 should be employed, or the solution evaporated to obtain more 

 acetate ; thirdly, that the peroxide formed, should be obtained 

 by precipitation for preparing the oxidum hydrargyri rubrum. 



Murias Hj/drargi/ri Corrosivm. — Two parts of mercury are 

 directed to be boiled with two parts and a half of sulphuric acid, 

 and the sulphate of mercury resulting is to be decomposed by 

 four parts of common salt. 



I have already noticed, that in preparing muriatic acid, the 

 College order common salt to be decomposed by an equal 

 weight of sulphuric acid, a quantity unnecessarily large. In 

 this instance, it appears to be supposed that the remaining por- 

 tion of two parts and a half of sulphuric acid vvhich the sulphate 

 of mercury contains are capable of decomposing four parts of 

 common salt. It is probable, but I do not speak with certainty^ 

 that at least 2*75 parts of the four parts of salt are in excess, and 

 totally useless. 



Submurias Hydrargifri Precipitatus. — In order to prepare 

 this, equal weights of diluted nitrous acid and mercury are to be 

 used to obtain a solution ofprotonitrate of mercury, which is to 

 be decomposed by muriate of' soda. The quantities of acid and 

 mercury appear to be perfectly well apportioned, scarcely an 

 atom of mercury remaining undissolved. In this case, as well as 

 in that of preparing the acetate of mercury, it is of great import- 

 ance that the mercury should not be converted into peroxide ; 

 but the directions are singularly inconsistent with each other» 

 In preparing the nitrate for the acetate, more acid is directed to 

 be used than is required for dissolving the mercury. In prepar- 

 ing the nitrate for the submuriate, the orders are with more 

 propriety directly reversed, more mercury being directed to be 

 added to the acid than it i% capable of dissolving. 



