116 Answer to Mr. R. Phillips's [Feb, 



Article VIII. 



Answer to Mr. R. Phillips's Animadversiotis on Mr. Hume, 



(To Dr. Thomson.) 

 SIR, 



Your Correspondent, Mr. R. Phillips, affords another example 

 of human imperfection, that we are all " prone to complain " and 

 often to publisli too, without any reason or foundation. 



Much of his valuable time, and more than nine-tenths of his 

 letter to you, might have been spared, had h? only looked into one 

 of the volumes of your own System of Chemistry. There he would 

 have found that, instead of dashing into a stream of words, studied 

 expressions and polished sentences, you have in a single line said 

 all that was necessary to correct where there was assuredly on 

 my side no intentional plagiarism ; for, speaking of the super- 

 sulphate of barytes, you say in a note, " Mr. Hume has also 

 mentioned it, but the fact was well known to chemists." To your 

 decision I have long ago assented, and have also abandoned all 

 claim to priority respecting the super-sulphate of strontian, after 

 I found that Mr. Clayfield, of Bristol, had anticipated my obser- 

 vations. 



Mr. R. Phillips is equally unfortunate in the two experiments 

 quoted from M. Sage ; he has drawn inferences diametrically 

 opposite to those of all the chemists who have written upon the 

 subject, especially those of France, In these experiments there 

 is neither water of solution nor ivater of crystallization', there is 

 no guide to direct future operators to avoid such errors as 1 shall 

 presently quote; nor is there any room for asserting, that putting 

 a quantity of carbonate of barytes into either of the two acids, 

 although it be granted that in such a case it must be converted into 

 a nitrate or muriate, is precisely the' same as adding these salts 

 or more particularly their solutions to the respective acids. There 

 is nothing here to invalidate what 1 have said on the subject; 

 nothing detailed by M. Sage to show the direct meaning and ten- 

 dency of the instructions which I took the liberty to offer, and 

 which may be thus epitomized : — That siich is the avidity ofvitrom 

 and muriatic acid for water, that they will attract even the ivhole of 

 the ivater of solution from their respective harytic salts. 



When I published my paper upon this subject, it had been a 

 common practice to ascertain the purity of nitrous acid, and even 

 to purify it, by dropping into it a solution of nitrate of barytes ; and 

 this method was pursued by some very eminent professional men. I 

 recollect one case in which a Gentleman, well known as a chemist 

 and mineralogist, condemned some nitrous acid which had been 

 sent to Sir Johu St. Aubyn, which, on my proving the error, was 



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