5(J Analyses of Books. [July, 



prised therefore, when 1 assure him that as far as that doctrine is 

 concerned, I found nothing which to me appeared new in his book. 



As to the third point, I consider it as the only material one ; for 

 in my opinion the art of weighing the atoms of bodies is the only 

 addition which Mr. .Dalton has made to the atomic theory ; but it 

 is an addition of the utmost importance, as it has set that theory 

 in a new point of view, and rendered it, from being a naked and 

 insulated and useless fact, the very basis and first principle of the 

 whole science. Accordingly it is to the few years that have elapsed 

 since that method was pointed out by Mr. Dalton that we are 

 indebted for almost all the accurate knowledge that we possess of 

 the composition of bodies. If Mr. Higgins, then, can make good 

 his claim to the discovery of determining the weight of the atoms 

 of bodies, the whole atomic theory will be his exclusively. Nay, 

 if he can show in his book the least hint at the weight of any one 

 atom, or that the weight of an atom can be ascertained, I shall 

 very readily admit the whole of his claim. 



In page ] I of the work, which I am at present examining, Mr. 

 Higgins says, " The relative weights of the different particles of 

 elementary matter, that of hydrogen being a standard, have also 

 been given by Mr. Dalton. I have done the same in many in- 

 stances. After this, the relative weight of compound atoms could 

 readily be conceived, and Mr. Dalton has extended this to saline 

 substances." Such is the assertion of Mr. Higgins, which he 

 repeats in various other passages of his book. Now after reading 

 over the whole of his quotations with attention, I find nothing but 

 the following passages on which he seems to found the whole of 

 these assertions : — 



Sulphuric " acid, exclusive of water, consists of two parts of 

 oxygen and one of sulphur by weight. 



'* One hundred and forty-three grains of oxygen gas contain 41 

 of water ; quicklime will abstract 26 grains from it, and the 

 remainder of its water cannot be separated by similar means; there- 

 fore 100 grains of sulphur require only 100 or 102 of the dry 

 gravitating matter of oxygen gas to form sulphurous acid. As 

 sulphurous acid gas is very little more than double the specific 

 gravity of oxygen gas, we may conclude that the ultimate particles 

 of sulphur and oxygen contain the same quantity of matter ; for 

 oxygen gas suffers no considerable diminution of its bulk by uniting 

 to the quantity of sulphur necessary to form sulphurous acid. It 

 contracts T ' T , as shall be shoun hereafter. 



" Hence we may conclude that an atom of sulphurous acid 

 consists of a single particle of oxygen and a single particle of 

 sulphur, chemically united ; and that every molecule of sulphuric 

 acid contains one particle of sulphur and two of oxygen, the pro- 

 portion necessary to saturation. 



tf As two cubic inches of hydrogen gas require but one cubic 

 inch of oxygen gas to condense them to water, we may presume 

 that they contain an equal number of divisions, and that the differ- 



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