388. Analyses of Books, [May, 



Let us suppose that when chloride of potassium is dissolved 

 in water, an atom of the fluid is at once decomposed, and muriate 

 of potash formed ; when tartaric acid is added to the solution, 

 bitartrate of potash is precipitated, and muriatic acid remains in 

 solution. In this case the decomposition of water only occurs ; 

 there is no recomposition, and the question is merely, does the 

 decomposition take place before the addition of the tartaric acid, 

 oris it determined bythepresence of tartaric acid, and on account 

 of its affinity for potash ? On the other hand, let it be granted that 

 when the aqueous solutions of muriatic acid and potash are 

 mixed to saturation, we have chloride of potassium in solution; 

 on this supposition water must be Jointed by the union of the 

 hydrogen of the acid with the oxygen of the potash ; and this 

 supposition is, perhaps, quite as probable as that, when chloride 

 of potassium is added to water that fluid is decomposed. Now, 

 however, to the solution of chloride of potassium which has been 

 formed by the composition of water, add solution of tartaric 

 acid, and then water must be decomposed, for potash is formed 

 and bitartrate of potash precipitated. In this case, therefore, 

 when employing perfectly similar ingredients, we must suppose 

 both the composition and decomposition of water, and admit the 

 latter to be eflected by predisposing affinity, a doctrine which is 

 now exploded ; it appears to us, therefore, that simplicity is 

 greatly in favour of the change which supposes that all chlorides 

 when dissolved in water become muriates, for then only one de- 

 composition occurs in circumstances which require a composition 

 and decom])osition, on the idea that chlorides remain such when 

 dissolved in water. 



The next observation which we would make is suggested by 

 what we find in p. 20. Dr. Turner considers that the only exception 

 to the regular law of combination is, " when one proportion of 

 one body combines with one proportion and a half, or two pro- 

 portions and a half of another body." Now, as it is proved, in 

 p. 34, that these compounds form no exception, it would, we 

 think, have been better to have introduced the explanation at 

 once; there is, however, one mode of showing that the existence 

 of sesquisalts forms no exception, and to which Dr. Turner has 

 not adverted, viz. that they are compounds of an atom of a salt 

 composed of one atom of acid and one of base, with one atom of 

 a bisalt. 



Dr. Turner has well pointed out a diflference between the 

 theory of volumes and atoms : he observes (p. 47), " The theory 

 of volumes has very considerable analogy to Mr. Dalton's law of 

 multiple proportions. The former is indeed, to a certain extent, 

 a consequence of the latter ; for if one body unites with another 

 in several proportions, the quantities of the variable ingredient 

 will stand m the same relation to one another, when expressed 

 by volume, as they do by weight. But there is one remarkable 



