on the Atomic Theory* 131 



S. If the water bulk of the above weight of acid be divided by 

 Dr. Thomson's specific gravity of the acid, we shall have its vo 



lume. Thus, — — . — ±S 1.379 cubic inch = 348.1975 grain mea- 

 1.1958 & 



sures ; and conversely its weight in grains, divided by its bulk in 



416.22 



grains, is its specific gravity sea 1.197 = 



* J 348.1975. 



After floundering through this mire of miscalculation, the 

 Doctor has the modesty to say, " All the tables hitherto published, 

 exhibiting the strength of muriatic acid of various specific gravi- 

 ties, are very erroneous, because they were constructed upon in- 

 accurate data. I conceive, therefore, that it will be worth while 

 to exhibit an accurate table of the specific gravity of this acid of 

 determinate strengths. My method was, to saturate a given 

 weight of the acid with calcareous spar." This is to out-Herod 

 Herod. " My method," as he calls it, is the old and usual one, 

 and was that employed in constructing a table of muriatic acid, 

 published in his own Annals of Philosophy for October ', 1817. But 

 the method with nitrate of silver is incomparably more delicate 

 and precise. 



What are we to think of that man's candour, who, after assert- 

 ing that all the tables of muriatic acid hitherto published are very 

 erroneous, gives as his own discovery, and as a standard of truth, 

 a little table, of which the fundamental numbers, viz., the specific 

 gravities corresponding to quantities of acid per cent, are appa- 

 rently taken, without acknowledgment, from a very extensive table 

 of muriatic acid published in this Journal, for January, 1822. The 

 slight disguise that the Doctor has put on his numbers, will never 

 make them pass for his own. 



Table in Journal of Science, Table in Dr. Thomson's 



Jan. 1822. Attempt, 1825. 



The fundamental strength at sp. gravity 1.20 is that from which 

 the numbers in the tables are deduced, and it is as nearly as may 

 be the same in both. We are confident that Dr. Thomson's small 

 deviations from the numbers given in our Journal for 1S22 are 

 errors ; but supposing them not so, the differences are so inconsi- 

 derable, as not to entitle the Doctor to say all the former tables 

 were " very erroneous." 



In his fifth chapter, Dr. Thomson treats of the atomic weight of 

 azote, and specific gravity of azotic gas. The usual felicity of co- 

 incidence between experimental and theoretic numbers attends his 



K 2 



