Remarkable Effecl of the Double Ele^ive AUraElions, 341 



Now, if by the fulphate of foda \<'e decompofe a quantity of muriate of barytes contain- 

 ing, according to the above table, 25,906 of muriatic acid, there ought to remain difen- 

 gaged, or in excefs, 16,710 ; — nevertheiefs the mixture remains neuter. 



The fluid remains alfo neuter, if we ceafe to add the folution of fulphate of foda when the 

 precipitate no longer falls down. The computation Ihews, that in a hundred parts of the 

 mixture of thefe two falts, in which the muriatic acid would be reprefented by ao, there 

 ought to remain 1 2 unfaturated, or in excefs. 



Let us apply the fame method of verification to the proportions determined by Kirwan in 

 the new tables in the fecond edition of his Differtation. 



It is known, that an exchange of bafes takes place between fulphate of foda and muriate 

 of magnefia. The computation eftabliflied on the proportions indicated by the tables fo 

 rigoroufly affumed from the real acids, always {hews a notable excefs of acid, either muria- 

 tic or fulphuric, accordingly as the quantity of one or the other of thefe falts is increafed in 

 the mixture. 



The doubts entertained by certain chemlfts on the refpeftive decompofition of thefe two 

 falts, have induced me to apply the fame calculation to the inverfe operation, that is to fay, 

 by mixing the folutions of fulphate of magnefia and muriate of foda ; and in this cafe alfo 

 the refults do not agree. 



Laftly, the method has been tried on a cafe of affinity, in which the decompofition Imme- 

 diately fliews itfclf by unequivocal figns; that is to fay, in the mixture of a folution of ful- 

 phate of potafti and nitrate of lime. 



According to the lafl; data of Kirwan, the proportions of the component parts of thefe two 

 falts, and the two others which ought to be formed, are as follows : 



Sulphate of Potalh - {^^^ J^^ 

 Sulphate of Lime . j^cid loo^ 



Nitrate of Potafh - {^f^^'H^^ 



f Acid 100 

 ime 34,4 



It is eafy to form the mixture of a quantity of fulphate of potafli^of which the acid fhall be 

 reprefented by the number 100, together withfomuchof the nitrate of lime that there fhall be 

 more than fufficient to caufe the whole of the fulphuric acid to pafs into a new combination. 

 It is evident that, to effeft this, 80,6 of lime will be required, which will therefore be difen- 

 gaged from 234,4 of nitric acid ; a quantity which would require for its faturation 195,32 

 of potafii. But it finds only 10,87. The quantity of nitric acid remaining without any 

 bafe, or in excefs, mufl; confequently be" 64,87. 



Such is the refult of calculation ; but experiment pronounces otherwife. The fluid di- 

 luted or concentrated, and even carried to cryflallization, did not at any period prefent the 

 leaft. trace of difengaged acid. 



The author declares in conclufion, that his intention is not to criticife experiments made 



with no lefs care than fagacity ; but to offer to chemifts a problem which is interefi;ing in 



many refpefts, theoretical, praftlcal, and even pharmaceutical ; a problem of which the 



folution is no longer to be fought in the amendment of fuch errors as are unavoidable in 



Vol. II. — Nov. 1798. Yy manipu- 



Nitrate of Lime - < ^ . 

 ILir 



