132 



SCIENCE. 



[N. S. Vol. IV. No. 83. 



tal throughout chemistry, the law of definite 

 and the law of multiple proportions. I^o 

 matter whether or not we hold to the atomic 

 theory, these would remain unalterable and 

 by their existence would inevitably force 

 the science to be a quantitative one. By 

 leaving this basis, or ignoring it, while still 

 keeping the atomic hypothesis in sight, even 

 great chemists have been led to adopt the 

 most impossible theories and to distort 

 the most carefully established facts, as the 

 history of Front's hypothesis abundantly 

 demonstrates. But, if the foundations of 

 chemistry are quantitative, why not begin 

 the study of it in such a way that this as- 

 pect is thoroughly and permanently brought 

 out to the attention of the student? The 

 difficulties in the way are not great; the 

 necessary equipment for the work does not 

 add a large outlaj^ to those expenditures 

 which all properly provided laboratories al- 

 ready have to meet, and in the majority of 

 cases experiments for beginners can be al- 

 tered from the qualitative to the quantita- 

 tive ones by the simple graduation of a 

 glass tube. The quantitative neutraliza- 

 tion of acids by bases and vice versa, easily 

 carried out with accurate results, is espe- 

 cially useful, combining, as it does, both the 

 laws of definite and multiple proportions 

 and the most striking chemical characteris- 

 tics of two important classes of compounds. 



The study of the combining volumes of 

 gases is also simple and necessary as lead- 

 ing up to subsequent important theoretical 

 considerations ; only by following a course 

 of accurate work can a proper basis be se- 

 cured for future generalizations. 



The atomic theory has no place in the be- 

 ginning of the study of chemistry. The re- 

 actions which students encounter during 

 the first period are as easily understood 

 without it as with it. Its early use is con- 

 fusing and pernicious, giving, as it does, a 

 visionary and immaterial basis for the 

 science, which is too apt to cling to the 



pupil throughout his subsequent course. 

 Our belief in this theory has been brought 

 about by the convergence of a number of 

 lines of investigation which have made use 

 of facts discovered both in physics and in 

 chemistry, and it should be dealt with in 

 this way. If we use it in any other we are 

 bringing ourselves back to the scientific 

 standpoint of Aristotle, whose deductions 

 were subjective and not objective. 



Chemical formulae are, of course, in their 

 present meaning, founded on the atomic 

 theory, and therefore are to be excluded 

 until after the proper work has brought 

 about their logical development. It is not, 

 however, inexpedient to introduce a few 

 symbols which represent not atoms, but 

 equivalent weights which are so related as 

 to be referred to one gram of hydrogen as a 

 unit, for by this means an advantageous 

 conciseness of expression can be obtained. 

 So, to use a concrete example, it can readily 

 be demonstrated that, by the action of cer- 

 tain metals on acids, a definite quantity of 

 hydrogen is substituted by a given weight 

 of each metal, and, if in such an experi- 

 ment we select the unit weight of hydrogen 

 as a basis of calculation, we have a means 

 at hand of ascertaining the reacting quan- 

 tities of the substances in question. These 

 relationships are further exemplified hy the 

 experiments on neutralization, so that, 

 finally, a few of the simple reactions can be 

 expressed by a system of notation which is 

 founded only on observed facts. In this 

 way a basis is obtained for further en- 

 largement and explanation when the time 

 comes to introduce theoretical deductions, 

 and thus the pupil can be brought to under- 

 stand the scientific means by which our 

 present system has been brought about. It 

 is too often the case that students who 

 have even had a somewhat extended chemi- 

 cal instruction are only able to present 

 their knowledge in a language of symbols, 

 of the fundamental meaning of which they 



