22 Clarke, TJie Atomic Theory. 



against hypercriticism ; none is absolute and final ; with 

 these considerations borne in mind we may ask whether a 

 doctrine is serviceable or not, and we can use it without 

 fear. When we say that matter, as we know it, behaves 

 as if it were made up of very small, discrete particles, we 

 do not lose ourselves in metaphysics, and we have a 

 definite conception which can be applied to the correla- 

 tion of evidence and the solution of problems. Objections 

 count for nothing against it until something better is 

 offered in its stead, a condition which the critics of the 

 atomic theory have so far failed to fulfil. They give us 

 no real substitute for it, no other working tool, and so 

 their objections, which are too often metaphysical in 

 character, command little serious attention. Criticism is 

 useful, just so far as it helps to clarify our thinking ; 

 when it becomes a mere agent of destruction it loses force. 

 Broadly speaking, then, the modern critics of the 

 atomic theory have shaken it but little. Still, some serious 

 attempts have been made towards forming an alternative 

 system of chemistry, or at least a system in which the 

 atom shall not avowedly appear. The most serious, and 

 perhaps the most elaborate of these devices was that 

 brought forward in 1866 by Sir Benjamin Brodie,* in his 

 " Calculus of Chemical Operations," which he defended 

 later (1880) in a little book entitled " Ideal Chemistry." 

 In this curious investigation, Brodie tries to avoid 

 hypotheses, and to represent chemical acts as operations 

 upon the unit of space by which weights are generated. 

 This notion is a little difficult to grasp, but Brodie's pro- 

 cedure was perfectly legitimate. His one fundamental 

 assumption is that hydrogen is so generated by a single 

 operation, and upon this he erects a system of symbols, 

 which, treated mathematically, lead to some remarkable 

 * Phil. Trans., 1866. A second part in 1877. 



