SCIENCE 



[N. S. Vol. XXVII. No. 701 



point of view is ever changing, and our 

 view of truth changes with it and is always 

 incomplete. It is the tangent to the curve 

 that represents the evolution of our knowl- 

 edge of the truth, and it coincides with that 

 curve only at that infinitesimal interval of 

 time that we caU now. As we look into 

 the future, it diverges more and more 

 widely from the truth, and we can only 

 keep in the true path by continually shift- 

 ing our view-point and continually chan- 

 ging our views. This is the first thing we 

 should teach our students. But our pres- 

 ent view of the truth, though certainly in- 

 complete, is not necessarily false. If our 

 data are reliable, if our measurements are 

 accurate, if our calculations are correct, it 

 does really represent the facts as we now 

 know them. It is real knowledge. It will 

 become out of date with the lapse of time, 

 but it will not be contradicted ; it will not 

 be exploded. This is the next thing to be 

 taught. The recognition of these two 

 cardinal principles constitutes the scientific 

 habit of mind. This is essentially the dif- 

 ference between the mental attitude of the 

 man of science and that of the man in the 

 street. Our first duty is to impress this 

 way of looking at things on the plastic 

 minds of our pupils, not by precept only, 

 but by example, by illustration, by reitera^ 

 tion till it becomes a part of their nature. 



But it is not enough to give a boy the 

 chemist's point of view. We must also 

 try, as far as time and opportunity allow, 

 to make him see the things the chemist sees. 

 We must get him to look beneath the sur- 

 face of the forms of matter that surround 

 him and discern, at least in some dim way, 

 the throbbings of the living forces within 

 them and around them. 



And here let us beware of serving up 

 knowledge in individual platters. Do not 

 let the student get into his head that there 

 is one chemistry of the metals and another 



of the non-metals, or that organic chem- 

 istry and inorganic chemistry have any 

 real existence except as guide cards in a 

 catalogue. 



The student's time is so short and so 

 crowded with other studies that only a few 

 types can be chosen. But let those types 

 be selected so as to cover, as far as may be, 

 the whole field; let them be as typical as 

 possible, and make the student understand 

 that they are types. Thanks to the great 

 Russian Pilot, this is an easy task now in 

 comparison with what it used to be in the 

 days when some of us launched our bark 

 on the yet uncharted sea. 



Above all things, let us see to it that the 

 student never for one moment flatters him- 

 self with the notion that what we require 

 him to know is all there is of chemistry 

 that is worth knowing! Let us make it 

 abundantly clear to him that we are only 

 teaching him to read the language of chem- 

 istry and that the selections we set before 

 him are only exercises in translation— not 

 a corpus poetarum. 



When I speak of teaching the student to 

 read the language of chemistry, I am using 

 no empty metaphor. This is the kernel of 

 the whole matter. What we have to do is 

 just this — to teach him to read chemistry ; 

 to interpret chemical phrases; to give him 

 clear notions as to the meaning of the con- 

 ventions by which the chemist expresses his 

 ideas. 



This, as I have said before, is mental 

 training of a high order. But it is more 

 than that. The utilitarian side of the 

 question must not be overlooked any more 

 than the cultural aspect. The time will 

 come, sooner or later, when the engineer 

 will want to find out what is known about 

 the chemistry of some subject in which he 

 is interested. Very likely his need will be 

 urgent; it is certain his time will be scant. 

 If he has had the education I speak of, he 



