102 On Chemical Equivalents. 



each a niultiijle of rhe first. By correcting and extendfny Rich- 

 ter's scale of reciprocal saturation, and reviving Mr. Higgins's 

 long neglected discovery of multiple proportion, Mr. Dalton has 

 been no mean contributor to the advancement of the science. 

 It is difficult to say how far his figured groups of spherical atoms 

 have been beneficial or not. They may have had some use iii 

 aiding the conception of learners, and j>erhaps in giving a novel 

 and imposing air to the atomical fabric. But their arrangement, 

 and even their existence, are altogether hypothetical, and there- 

 fore ouglit to have no place in physical demonstrations. 



That water is a compound of an atom of oxygen and an atom 

 of hydrogen, is assumed by Mr. Dalton as the basis of his system. 

 But two volumes of hydrogen here combine with one of oxygen. 

 He therefore infers, that an atom of hydrogen occupies double 

 the bulk, in its gaseous state, of an atom of oxygen. These as- 

 sumptions are obviously gratuitous. 1 agree with Dr. Prout in 

 thinking that Sir H. Davy has taken a more philosophical view 

 of this subject. Guided by the strict logic of chemistry, he 

 places no hypothesis at the foundation of his fabric. 



Experiment shows, 1st, That in equal volumes oxygen weighs 

 IG times more than hydrogen; and 2dly, That water is formed 

 by the union of one volume of the former, and two volumes of 

 the latter gas, or by weight of 8 to 1. We are not in the least 

 authorized to infer from this, that an atom of oxygen weighs 

 S times as much as an atom of hydrogen. For aught we know, 

 water may be a compound of 2 atoms of iiydrogcn, and 1 of oxy- 

 gen ; in wliich case we should have the proportion of the weights 

 of the atoms,as given by equal volumes, namely, 1 to 16. There 

 is no good reason for fixing on one compound of hydrogen, more 

 than on another, in the determination of the basis of the equiva- 

 lent scale. If we deliberate on that combination of hydrogen «• 

 which its agency is apparently most energetic, namely, that with 

 chlorine, we should surely never think of pitching on two volumes 

 as its unily or least proportion of combination ; for it is 07ie 

 volume of hydrogen which unites vvith one volume of chlorine, 

 producing two volumes of muriatic gas. Here, therefore, we see 

 that one vohnne o! hydrogen is quite adequate to effect, in an 

 active gaseous body of equal bulk, and 36 times its weight, an 

 entire chaiige of properties. Should wc assume in gaseous ciie- 

 mistry, 2 volumes of hydrogen, as the combining unit, or as re- 

 presenting an atom ; then it should never unite in 3 volumes, or 

 an atom and a half with another gas. Ammonia, however, is a 

 compound of 3 volumes of hydrogen with 1 of azote; and if 

 2 volumes of hydrogen to I of oxygen be called an atom to an 

 atoni_, surely 3 volumes of hydrogen to I of azote should be 



called 



