/ 



2 lo ' C« f^' Strength and Properties of 



pediquc, for May, 1766, in which there is a long article on the fubje<ft, gives his fenfe ts 

 the word, and adds, that the principles, according to which fpeflacles are fabricated, arc 

 found in Euclid. and the ancient geometers. 



VII. 



Obfervations on the Proportion of real Acid in the three ancient known mineral Acids, and on 

 ■ the Ingredients in various neutral Salts and ether Compounds* By RiCHARD KlRH^ANt 

 Es<^ LL.D. F.R.S. and M.R.IA. 



X HE fundamental experiments on which the proportion of real acid in the three minersd 

 acids anciently known, and alfo the proportion of ingredients in many neutral falts, were 

 determined, are fet forth in a paper of Mr. Kirwan, in the IVth vol. of the TranfaSions of 

 the Irifh Academy. That paper contains tables of the quantity of ftandard acid exifting in i09 

 parts of each of the acid liquors, of given fpecific gravities, and alfo in each of the neutral falts 

 therein mentioned, according to a method which Mr. Kirwan has fince difcovered to be very 

 inconvenient, becaufe fome of thcfe neutral falts contain an acid ftili ftronger than the af- 

 fumed ftandard. It is there alfo noticed, that the ftrongeft vitriolic acid now known exifts in 

 vitriolated tartarin, the ftrongeft nitrous acid in nitrated fodn^ and the ftrongeft muriatic acid 

 in muriated tartarin. Acids of fuch ftrength he has, therefore, denominated real, as either 

 containing no water, or containing only as much as is neceflary to their eflential compofition, 

 as far as is at prefent known. The method of transforming the expreffion JIandard into that 

 of real, is given in the fame paper at p. 67, and by it he has formed the table here prefented. 

 This latter expreflion he therefore employs in every cafe inftead of that of ftandard, together 

 with the fubftitution of a more commodious expreflion of the ftrength of acids. Another 

 obje£t of his prefent communication is, to exhibit an illuftration or amendment of feveral of 

 the determinations contained in his laft, which, being for the moft part fingle, required con- 

 firmation, by fliewing their agreement with the experiments of feveral of the moft eminent 

 chemifts, made fince that publication, that is, fince the year 1791, with a few made nearly 

 at the fame time. In his former paper he compared his refults with thofe of Bergman and 

 Wenzel, they being almoft the only perfons who had made this fubje£t the principal objedl of 

 their enquiry, and had purfued it to a confiderable extent. In each particular inftance he 

 traced the reafon of the difference of their refults from his own, when it was fuch as to deferve 

 notice: he does not, therefore, repeat what was there obferved; but cannot avoid again men- 



buxus (box), and denotes the little box in which the letter was contained. According to this interpretation, 

 the above may be thus tranflated. " As foon as I faw the bearer of your letters, I feized the fmall box 

 which contained them, and frequently read them over with avidity;" and not that I fnatched up my fpec- 

 tacles. Note of citizen Millin. 



• Abridged from an exteiifive paper, which will hereafter appear in the Tranfaflions of the Royal Iriih 

 Academy. I was favourec',by the author, with this paper, entitled, Additional Obfervations, Sjc. 



tionins 



