256 THE ATOMIC THEORY. 



science. Some of the objector.s are quite dogmatic in their utterances; 

 some only seek to evade the theory without going- to the extreme of 

 an absolute denial, and still others, more timid, assume an apologetic 

 tone, as if the atom were something like a poor relation — to be recog- 

 nized and tolei-atod, Ijut not to l)e encouraged too far. Now, caution 

 is a good thing if it is not allowed to degenerate into indecision; when 

 that happens mental obscurit^y is the result. In science we must have 

 intellectual resting places; something to serve as a foundation for our 

 thinking; something concrete and tangible in form. No theory is 

 immune against hypercriticism; none is absolute and final. With these 

 considerations borne in mind we may ask whether a doctrine is serv- 

 iceable 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 detinite conception which can be applied to the correlation of evi- 

 dence 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 theor}^ have so far failed to fultill. 

 They give us no real sul)stitute for it, no other working tool, and so 

 their o])jections, which are too often m(>taphysical in character, com- 

 mand little serious attention. Criticism is useful just so far as it helps 

 to clarity our thinking; when it ])econies a mere agent of destruction 

 it loses force. 



Broadly speaking, then, the modern critics of the atomic theory 

 have shaken it Init little. Still, some serious attempts have been made 

 toward forming an alternative system of chemistry, or at least a system 

 in which the atom shall not avowedl}^ appear. The most sei'ious and 

 perhaps the most elaborate of these devices was that brought forward 

 in 1866 by Sir Benjamin Brodie" in his Calculus of Chemical Opera- 

 tions, 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 l)y which weights are generated. This notion is a little difficult 

 to grasp, but Brodie's procedure 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 conclusions. For instance, 

 chlorine, bromine, iodine, nitrogen, and phosphorus become com- 

 pounds of hydrogen with as many unknown or "ideal" elements, 

 which no actual analysis has yet identified. That is, the known phe- 

 nomena of chemistry seem to be less simply interpreted by Brodie's 

 calculus than in our commonly accepted theories, and certain classes 

 of phenomena ai-e not considered at all. It is true that Brodie never 

 completed his work, but it is not easy to see how his notation and 



<' Phil Trans., 1866. A Hecond part- in 1877. 



