1824.] Pharmacopoeia Londiriensis. 453 



tubes which, on common occasions, would be used for conveying 

 the gas, would soon be choked with crystals, and the whole 

 apparatus would probably be blown to atoms. 



With respect to sulphate of potash, the College would have 

 acted economically in imitating the directions of the Edinburgh 

 Pharmacopoeia, by saturating the excess of acid of the bisulphate, 

 with lime instead of potash ; by this the waste would have been 

 avoided, of using a salt of greater value to obtain one of less. 

 But as potass* sulphas is now also in the Materia Medica, 

 the chemist, may avail himself of those economical modes of 

 operating which the College have too frequently neglected, and 

 that without any attendant advantage. The same remarks will 

 also apply to the preparation of sulphate of sod a. 



The directions for preparing that important medicine, tarta- 

 rized antimony, are most exceedingly and unequivocally improv- 

 ed : tiiere is indeed nothing new in the process, but it is simple 

 and effectual; whereas the method which has given place to it 

 was the worst, considering that it really was practicable, that 

 ever was devised. The College have now directed the use of 

 the glass of antimony, but I think that the proportion ordered 

 is rather too small to convert the whole of the tartar into tartar- 

 ized antimony. 



The preparation which I shall next notice is the vinum anti- 

 monii tartarizati. In those preparations in which wine was 

 formerly employed, the College have now directed very dilute 

 spirit to be used, still retaining, however, with unquestionable 

 impropriety, the appellation ot'viinim. In the present instance, 

 I am not aware that the change has been either beneficial 

 or otherwise; but I shall presently notice a preparation in 

 which the alteration has been decidedly hurtful, because the 

 College, without seeming to have been aware of the fact, have 

 much weakened the medicine. Added to this, dilute spirit of 

 very different degrees of strength is now used instead of wine, 

 which must, 1 think, have been more uniform in its power. 



Among metallic preparations a place has been given to subni- 

 trate of bismuth. The process, which is extremely simple, I 

 have not examined ; but even if the metal or acid should either 

 of them be in excess, the precipitate will at any rate be obtained 

 without difficulty. 



With respect to the preparations of iron, there have been 

 some alterations which are to be considered as amendments; 

 but I am apprehensive that the good which has been done is 

 more than counterbalanced by the omission of improvements, or 

 the commission of errors. 



Ferrum ammoniatum is so weak a preparation as, perhaps, 

 scarcely to be worthy of notice ; the process for obtaining it has 

 been altered ; it could scarcely have been rendered worse, and 

 yet I do not think it has been improved. In the late Pharma- 

 copoeia this preparation was directed to be formed by subliming 



