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30 ~" Cnthi chemical HabHudts and 



Letter to the Editor from Mr. Willjam^ Henry, on his Difcovery of a new and int' 

 proved Method 0/ preparing the Prujiate of Pol-ajh; and on the dif puled Qjueflion, 

 Whether Prujiate of Pot-ajh be decompojedhy Muriate of Barytes? 



I 



Manchejler, March 21, 1800. 

 SIR, J > i^ 



N confequence of a paper, infertcd in your Philofophical Journal, I have been favoured 

 with the following letter from Mr. Kirwan. As the references, which it contains, to au- 

 thorities on a difputed point, may be interefting to others as well as to myfelf, I take the 

 liberty of fending you a copy of it for publication ; premifing, that I have ftated to Mr. K. 

 my intention of making you this communication, and tliat he has not exprefled any ob- 

 jection. 



•' To Mr. William Henry. 

 « Dear Sir, 

 " On looking over Mr. Nicholfon's valuable Philofophical Journal, which, though of 

 " ancient date, I had not until lately leifure to infpe£b, I find, in the 29th No. Vol. ii. 

 " p. 170, that you feem to regret I had not mentioned on what grounds I denied the pre- 

 " cipitation of barytic earth from muriatic acid by the Pruflian alcali, and then fuggeft that the 

 " relation of the Pruflian alcali to this earth had not been an obje£t of attention to Klaproth 

 ** or Pelletier, &c. I hope, therefore, it will be agreeable to you that I {hould ftate thofc 

 *' grounds. That Pruflian alcali, properly prepared, does not precipitate barytic folutions, 

 •* was firft proved by that accurate chemift, Mr. Meyer, of Stetin, as you may fee in 2 

 '• Crell's Chemical Annals for 1786, p. 142, 143. As I fuppofe you have that work, I 

 " Ihall not trouble you with the detail of his experiments. You may, alfo, fee that both 

 " Pelletier and Klaproth did treat of this faft, Pelletier affirming the precipitation of this 

 *• earth by the Pruflian alcali (21 Journal des Mines, p. 45) ; and Klaproth exprefsly deny- 

 " ing it, and aflerting that Pelletier was miftaken. (See 2 Klaproth, p. 91.) 



*' I am, dear Sir, 

 " With high regard and refpetl, &c. 



" R. KIRWAN." 

 ** Dubliny Jan. 20. 



Unfortunately it is not in my power to confult any one of the works, to which Mr. K. 

 has kindly referred me ; and highly as I refpedl the authorities, to which he has appealed, 

 yet I did not feel difpofed to acknowledgp myfelf in an error, till convinced by a circum- 



3 ftantial 



