en the Atomic Theory. 139 



of barytes, and to another portion of the same, sulphuretted hy- 

 drogen or prussiate of potash. In the first case, a copious pre- 

 cipitate of sulphate of barytes will prove the presence of sul- 

 phate of soda ; in the second, sulphuret, or ferro-prussiate of 

 lead, will fall. In fact, let solutions of sulphate of soda and ace- 

 tate of lead be mixed in the proportions indicated by Dr. Thom- 

 son's atomic weights of these salts, or in the most exact equiva- 

 lent proportions ; a portion of sulphate of lead will fall, and a 

 corresponding portion of acetate of soda will be formed. To 

 the supernatant liquid, (of any atomic proportion,) add carbonate 

 of soda, and carbonate of lead will be separated in abundance. 

 When the alkali ceases to act, let a current of sulphuretted hy- 

 drogen be passed through the supernatant liquid, and sulphuret 

 of lead will appear. Thus also ferro-prussiate of potash will 

 detect lead in a solution, when the proportion is too minute for 

 the carbonate of soda test. 



Dr. Thomson, from his unaccountable ignorance of these gra- 

 dations of affinity, has given, as experimental results, quantities 

 which it was impossible to obtain by the method of precipita- 

 tions. And, hence, had they not been rendered conformable to 

 the researches of Berzelius and other accurate chemists, as well 

 as to the theory of equivalents, the odds would have been ten to 

 one against Dr. Thomson's numbers in almost any case. 



The above remarks apply strongly to his sections on citric, 

 tartaric and acetic acids. And we are somewhat surprised that 

 he should expect any attention to his experiments on the ultimate 

 analysis of vegetables, in which upwards of nine grains of the 

 above crystalline acids are treated with only 200 grains of per- 

 oxide of copper. No certainty of their thorough decomposition, 

 by the oxygen of the ignited oxide, can be ensured ; and the re- 

 sult must be destitute of all authority. 



We have now adduced ample, even superfluous, evidence, of 

 the strongest negligence or incapacity in the conduct of his re- 

 searches on the atomic theory. And moreover, the perplexity 

 into which he runs, in considering the partial and erroneous ca- 

 nons of Berzelius, is a decisive proof that his general views are 

 neither clear nor comprehensive. In our Journal for January 

 1822, page 307, we endeavoured to shew the fallacy of these 

 pretended general laws of Berzelius. This development of ours 

 seems to have fallen under the Doctor's talons in an unhappy hour ; 

 for he tortures and disguises it most unmercifully. We request 

 our readers to compare the passage referred to in our Journal, 

 with Dr. Thomson's " few words respecting Berzelius's law," at 

 p. 469, et seq. of his lid. volume. 



The style of writing adopted by the doctor, in this new work, 

 ill accords with the lofty panegyric pronounced by himself, on 

 his literary attainments. / am remarkably concise, tluough I hope 



