262 



SCIENCE 



[N. S. Vol. XXXIV. No. 870 



hydrogen chloride, the gas, and silver ni- 

 trate, the solid, are brought together. 

 Perhaps the change represented would 

 actually take place, if the conditions were 

 favorable; let us assume that it would. 

 Throiighout the books, however, equations 

 of this type are employed to represent re- 

 actions "in solution"; i. e., in the case se- 

 lected, when hydrochloric acid (a solution 

 of the gas in water) is poured into an 

 aqueoiis solution of silver nitrate. 



Now, it is obvious that the use of sym- 

 bols is just as legitimate in chemistry as 

 it is in mathematics; and although an ex- 

 perienced analyst would attend to many 

 matters not referred to in the symbol, 

 would use rather more hydrochloric acid, 

 and would expect to get rather less silver 

 chloride than the quantities represented 

 in the equation, yet considering its brevity 

 the symbol gives a fairly accurate idea of 

 the quantities involved, it is therefore of 

 considerable practical use, and deserves 

 careful explanation in the texts. No such 

 explanation is offered, and indeed none is 

 needed by those who regard solutions as 

 mechanical mixtures; in their eyes the 

 water has as little right to representation 

 in the chemical equation as has the glass 

 of the beaker in which the precipitation is 

 made. 



Prom such a starting point, however, a 

 clear idea of the meaning of our present 

 formulation of solutions is not to be 

 reached; the high school treatment of am- 

 monium hydrate and carbonic acid — dis- 

 cussions of the probability of "chemical 

 combination" between ammonia and water, 

 for instance, without first fixing the 

 meaning of the term — only makes things 

 worse ; and in the end we find the children 

 "believing" in ions, or "disbelieving" in 

 hydrates-in-solution, just as a few years 

 before they believed in fairies. The idea 

 that our present method of formulating 



solutions is but a more or less imperfect 

 symbolic representation of laboratory 

 facts, will come upon them later, if it ever 

 comes upon them, like the discovery that 

 Santa Glaus is but a kind thought; one 

 experience of that kind ought to be 

 enough. 



Bacon says — I quote at second hand 

 through Huxley — that "truth comes out 

 of error much more readily than out of 

 confusion," and Freeman, speaking of his- 

 tory, says that "the difference between 

 good and bad teaching mainly consists in 

 this, whether the words used are really 

 clothed with a meaning or not. ' ' Is chem- 

 istry so different? Are vagueness and 

 dodging really necessary in the text-books 

 of our science? They are, so long as in 

 the theoretical part the conception of con- 

 tinuity is negatived, while in the practical 

 part experiments are described which 

 have forced that conception into the sci- 

 ence. 



A change is unavoidable; but it is 

 wholly unnecessary to give up the inter- 

 esting chemical experiments for prosy dis- 

 quisitions on water, ice and steam, or to 

 fill the book with "How Old Is Ann" 

 thermodynamical problems adapted from 

 van Laar. Striking phenomena are as in- 

 teresting to beginners to-day as they were 

 a hundred years ago, but gradations too 

 exist, and their existence must not be de- 

 nied. 



Until this change is made, children will 

 be trained to accept obsctire equivocal and 

 dogmatic statements in place of clear and 

 exact thought, and to be glib with words 

 they do not understand. Such discipline, 

 enforced in the name of science, of our 

 science, far from ensuring the results 

 prophesied by those whose efforts ob- 

 tained for these new studies the place they 

 now occupy in the schools, can hardly fail 

 to injure pupil and teacher alike, depriv- 



