g04! Mr Johnston's Visit to Berzelius. 



spared, it being by no means usual in this country for chemists 

 to declare each other unworthy of credit. There may be, and 

 no doubt there are, several errors in a book professing to give 

 the results of so great a number of analyses, but these ought 

 rather to have been pointed out singly than sweepingly an- 

 nounced ; and if common courtesy was not enough to secure 

 this, the respect due to a chemist who has dedicated a whole 

 life to the advancement of the science, ought to have been an 

 ample title to due forbearance. Of Thomson's results, Ber- 

 zelius says first, that the method employed for obtaining them 

 may in some cases admit of very good approximations, but 

 that it cannot at all be depended on for precise atomic 

 weights ; for, second, suppose we knew beforehand the precise 

 atomic weights of two bodies, yet unavoidable errors in the 

 weighing are sufficient to prevent exact mutual saturation ; 

 and lastly, that to have performed as they ought, all the analy- 

 ses given, would have taken a lifetime. On these grounds, 

 added to some errors he has found, he rejects the whole work, 

 weights and all, — of course in favour of his own. 



Berzelius himself allows of Dr Thomson, that he is an accu- 

 rate observer of phenomena, that he is moreover the most 

 learned chemist in England, — the most fearless in expressing 

 his opinion, regardless of high names, and the most willing to 

 do every man justice ; and that, had he confined himself to the 

 office of a redacteur, he would have earned a high and deserv- 

 ed reputation. Now, after all these honourable admissions, 

 surely his writings are not to be repudiated on account of er- 

 rors in manipulation, into which the theory he has adopted 

 may at times have led him ; much less ought they to be held 

 up to scorn as so much quackery, and the veracity of their 

 author called in question because his experimental results hap- 

 pen in some cases to be incorrect. Chemists on the continent, 

 among whom Berzelius is every thing, are shy of speaking of 

 Thomson. They do say " II fait ses experiences un peu en 



tique upon his own Mineralogy, published in the first volume of the 

 Quarterly Journal of Science, and which called forth so severe a note from 

 Dulong in the Annates de Ckimie. " This critique," says Berzelius, 

 '* was so severe as to make me laugh," Did he expect that saying still 

 severer things was to make Dr Thomson sing ? 



