36 Mr. Phillips's Reply to Dr. Hope. [July 



of mercury obtained by potash, I added nitric acid ; it was rea- 

 dily dissolved, and to the solution I put some nitrate of silver. 

 Not the slightest' precipitation of chloride of silver occurred, 

 showing that the decomposition was perfect. This operation 

 requires only a few minutes for its completion. 



Subsulphas Hydrargyri Flams- — You have not thought it worth 

 while to notice an inconsistency which I pointed out in your 

 directions for this preparation. It is to be formed by boiling 

 together two parts of mercury and three of sulphuric acid; 

 whereas in preparing corrosive sublimate, the proportions are two 

 of mercury and two and a half of acid. I cannot imagine any 

 cause for the variation, which, however, is not very important. 



Mvrias Hydrargyri Corrosivus. — I have not had time to deter- 

 mine experimentally what proportion of common salt is required 

 for the decomposition of sulphate of mercury ; but until I am 

 convinced by experiment, I think. I shall retain my opinion, that 

 the quantity which you have directed to be used is very unneces- 

 sarily large. 



Oxidum Hydrargyri Rubrum per Ac i dam Nitririan. — Permit 

 me to remark, that this is one of those names which would have 

 been improved, by subjecting it to curtailment equal to that 

 bestowed upon the tartras potassse et antimonii. 



For preparing this oxide of mercury, you direct three parts of 

 mercury to be dissolved in four of dilute nitrous acid, and to 

 these proportions I objected because three parts of acid are 

 equal to produce the effect; as ordered in preparing the submu- 

 rias hydrargyri prcecipitatus. In your reply, you say, " If the 

 diluted nitric acid have been formed from the strongest acid, 

 you are perfectly correct in saying, that it will dissolve an equal 

 weight of mercury, and in that case more acid is ordered by the 

 Edinburgh College than is necessary for preparing this substance. 

 But if the best acid usually met with in apothecaries' shops be 

 employed, in consequence of its inferior strength, the proportion 

 assigned in the Pharmacopoeia will be found most suitable." 



Wow this, I must confess, appears to me to be a most extra- 

 ordinary kind of defence. You tell me that your Pharmacopoeia 

 possesses " a certain degree of national authority in the prepa- 

 ration of drugs ; " but I think you would have been more discreet 

 in allowing, that I had detected an error of no very great import- 

 ance, than thus to admit that the authority which you possess is 

 of so trifling a nature, that you legislate in one part of the Phar- 

 macopoeia to accommodate those who contravene the directions 

 of the other. This declaration perfectly satisfies me, that however 

 I might have flattered myself as to the utility of my remarks, 

 nothing which I have yet done, or ever can perform, will be in 

 the least degree advantageous to your Pharmacopoeia. Hoping, 

 however, that the public may derive some utility from the expe- 

 riments which I have detailed, I am, Sir, yours, very respectfully, 



Richard Phillips. 



