198 THE POPULAR SCIENCE MONTHLY. 



ments to give him the spirit of the method, he will usually comprehend 

 the full significance of others which are plainly exhibited before him. 



In the third place, quantitative as well as qualitative experiments 

 are introduced from the first, and all the usual measurements of chem- 

 istry are illustrated. Examples are given of the determination of melt- 

 ing and boiling points, the student first constructing the thermometer 

 with which the determinations are made. He further learns how to 

 measure with the calorimeter the amount of heat evolved in chemical 

 processes, and to find the specific heat of the materials used. There are 

 also simple examples of quantitative analysis and of tbe determination 

 of molecular and atomic weights ; and, lastly, easy methods of deter- 

 mining gas and vapor densities place even those measurements within 

 the reach of elementary students. 



In the fourth place, great pains have been taken to reduce the ex- 

 pense of the course to the lowest possible point. To this end common 

 household utensils such as may be made by a tinsmith, or found at any 

 house-furnishing store, have been adapted to the purposes of instruction. 

 The small (so-called " American ") petroleum cooking-stove serves an 

 admirable purpose for heating, its oven is an excellent drying-chamber 

 or hot-air bath, and, with a simple attachment furnished by the mak- 

 ers, it may be used as a tube-furnace. So also a farina-kettle makes a 

 good steam-bath ; and the quick-sealing fruit or milk jars are not only 

 good gas-holders, but enable any student to perform experiments 

 which formerly were only made with costly apparatus. The only appa- 

 ratus of precision required are the scales and thermometers, which can 

 be purchased from the dealers in chemical supplies at a very moderate 

 cost. Indeed, the expense of the absolutely necessary outfit for a class 

 of twenty students need not exceed one hundred dollars, and twice 

 this sum will purchase everything that could possibly be needed for 

 the course here laid out. 



Lastly, the course has been made inductive throughout. It is a 

 wise economy in education to seek from each study that discijtline 

 which it best affords. The memory is a greatly abused faculty. The 

 necessities of language, the commonplaces of history, and the require- 

 ments of literature and art, task even the most retentive memory, and 

 it is a waste of resources to overburden it with a mass of scientific 

 details which, even if retained, will be of little value except to the 

 specialist. Chemistry is peculiarly an inductive science, and to teach 

 it deductively is to use it for a discipline, which is much better fur- 

 nished by mathematics or mechanics ; yet chemistry is taught deduc- 

 tively whenever, as in most elementary text-books, the chief stress is 

 laid upon the symbolical expression of chemical facts and principles. 

 To secure the peculiar discipline of chemistry, it is essential that it 

 should be studied as it has been built up. The student must begin 

 by observing phenomena, and be led up to the general principles 

 through his own inferences. To besrin with an abstract statement of 



