1626.i Dr. Turner on the Atomic Theory, 387 



justly remarks that the doctrine of which he treats has been 

 neglected from " a confused notion that it is a subject of great 

 difficulty ; that it is connected intimately with hypothetical 

 reasoning ; and that, consequently, it is neither a necessary 

 object of study, nor of sufficient importance to give a fair return 

 for the labour bestowed in comprehending it," — ^^(Preface, p. iv.) 



Dr. Turner has divided his work into six sections; 1. On the 

 laws of chemical combination ; 2. Views of Mr. Dalton on the 

 atomic theory; 3.M. Gay Lussac's theory of volumes ; 4. Pecu- 

 liar views of Prof. Berzehus; 5. On the hydracids ; 6. Table of 

 atomic weights. 



In the first section there are a few statements which call for 

 observation, and we are sure that Dr. Turner will not be dis- 

 pleased if we should offer some remarks, tending, as we 

 trust, to render his work, in a few instances, and only a few, 

 more correct. In the first place (p. 11), in speaking of the 

 compounds of sulphur and oxygen, the oxygen is termed the 

 " variable ingredient." Now we have no objection to this term, 

 provided it mean nothing more than that, assuming sulphur as a 

 standard, the quantity of the oxygen varies in different com- 

 pounds ; butweare apprehensive that the learner might misunder- 

 stand the phrase, and not perceive that the sulphur is the variable 

 ingredient, if we were to assume oxygen as the standard. 



In p. 19, Dr. Turner alludes to a part of the subject which 

 has been much discussed, and upon which it is extremely diffi- 

 cult to decide satisfactorily ; it is, perhaps, even impossible to 

 perform a conclusive experiment; we allude to the action of water 

 upon those chlorides which are soluble in it, and the nature of 

 tne changes which they suffer. Dr. Turner asserts with, we think, 

 rather too little hesitation, that when 56 of chloride of calcium 

 are " put into water, one proportion of that fluid is decomposed, 

 and both its elements are employed in reproducing muriate of 

 lime." Now this is, we conceive, begging the question ; for we 

 have no proof of the existence of such a salt as muriate of lime ; 

 there is no improbability, a priori, that chloride of calcium should 

 exist as such in solution ; the question is resolvable into two 

 cases; viz. whether when an aqueous solution of muriatic acid 

 is added to an aqueous solution of lime, chloride of calcium and 

 water are formed; or whether when chloride of calcium is dissolved 

 in water, muriate of lime is produced, as Dr. Turner states, and 

 as we beheve, to be the case, by the decomposition of water 

 whole question is, therefore, one of probabilities, and that may 

 fairly be assumed to be the true explanation which involves the 

 fewer difficulties. 



We have said that our view of the subject coincides with that 

 of Dr. Turner, and as we do not remember to have seen the case 

 put exactly on the grounds which support our opinion, we shall 

 take the opportunity of stating it. 



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