Septemeek 22, 1922] 



SCIENCE 



321 



practically all texts written for the beginner 

 in chemistry start in with oxygen, hydrogen, 

 the gas laws, and water, to be followed soon 

 with atoms, molecules, symbols, forainlas and 

 equation writing. It has always seemed to me 

 more logical to start, not with gases, but with 

 some solids, such as metals, with which the 

 student may have had some slight acquaintance 

 before entering the class. It is my belief that 

 the ordinary student can at first get more 

 tangible results from the more tangible sub- 

 stances, and that introducing him from the 

 start to gases which he can hardly see, smell, 

 taste, or handle is likely to discourage him 

 from the start, particularly if these introduc- 

 tory substances are tangled up with that bug- 

 bear to so many students — the gas laws. A 

 splendid opportunity is lost to tie the subject 

 from the beginning in the student's mind to 

 things that he has handled, or can handle, 

 easily in every-day life. 



My convictions were so strong that some 

 years ago I worked out a scheme of experi- 

 mentation in which the student started with 

 such common metals as copper, zinc and iron, 

 and followed these with magnesium, phos- 

 phorus and mercury. After a rather full 

 study of the properties of the elements them- 

 selves, heating them in air introduced him to 

 the subjects of oxidation and combustion. 

 Without going into details, I might say that 

 the first ninety experiments led him through 

 sulfur, carbon and chlorine and the acids 

 formed from these, the analysis and synthesis 

 of water, and then sodium, potassium and cal- 

 cium and their common compounds in such a 

 way that each experiment grew naturally out 

 of those preceding it and led up to an investi- 

 gation of a (to him) unknown substance, 

 namely, saltpeter, which he investigated by 

 means of sulfuric acid and by appropriate ex- 

 periments on the distillate, with the result that 

 by this procedure he determined for himself 

 the composition of both saltpeter and nitric 

 acid. All of this work was completed without 

 the mention of atom or molecule and without 

 a symbol or a formula. It is my belief that 

 the performing of these ninety experiments 

 revealed to the student the methods of thought 

 used by the chemical investigator in attacking 



his problem — the same method that he (the 

 student) should use on a small scale in solving 

 his own difficulties. I tried in this way to 

 teach the student how to think his own way 

 out of his difficulties. 



You will probably be asking if no equations 

 were used in these experiments. Yes, there 

 were — the kind of equation that McPhei-son 

 and Henderson hint at in their chapters on 

 oxygen and hydrogen in both of their texts. 

 Newell, Brownlee, Black and Conant and some 

 others use the same device to a limited extent, 

 but I developed that form of equation writing 

 so that instead of using the names of the com- 

 pounds with pluses and arrows, the student 

 early got into the habit of representing each 

 chemical reaction by an equation in which each 

 compound was represented by the names of 

 the elements which they had discovered that 

 compound to contain, each compound being 

 enclosed in a set of brackets. By this method 

 the students acquired a very personal and first- 

 hand acquaintance with the behavior of many 

 chemicals with each other, and they got a very 

 good conception, based upon actual laboratory 

 work, that certain compounds contained such 

 and such things, not because the formula was, 

 for instance, NajSO^, not because the book said 

 so, but because they had proved it themselves. 

 It must be admitted that such an attitude in the 

 student's mind is not to be scoffed at. The 

 main question that arises is: "Have we time 

 nowadays for such a method, or is the subject 

 so big that we must present the material in a 

 pretabulated and almost in a predigested 

 form?" 



Of course this set of ninety experiments was 

 simply introductory to text matter on the 

 theory in chemistry with experiments to illus- 

 trate, the laws and principles. Then came sym- 

 bols and formulas and their use in equation 

 writing, and finally considerable descriptive 

 chemistry studied in the light of present the- 

 oretical conceptions, but with the spirit of the 

 inductive method still an unconscious guide. 



It is only fair to say that in those years each 

 student performed probably 150 or more ex- 

 periments, and that although it was my opinion 

 that he was being taught chemistry rather than 

 a text-book, the school year was not long 



