ON THE STUDY OF PHYSICS. 59 



or ol* the relation of the parts of an organism to one another there is 

 obviously nothing in common between the observational deductions made 

 in the biological laboratory and the quantitative measurements of the 

 physical laboratory. 



The divergence between the functions of the chemical and the 

 physical laboratory is hardly less marked. While chemistry has ir- 

 refragable claims to designation as an exact science, the enumeration of 

 the chief laws discovered up to the present is a simple matter and 

 does not make a very imposing list. They are : 



The law of the conservation of matter. 



The law of constant proportion. 



The law of multiple proportion. 



The law of volumes or Avogadro's law. 



The law of specific heats or the law of Dulong and Petit. 



The law of periodic groups or Mendelejeff's law. 



The law of electrolytic dissociation. 



The law of isomerism. 



The law of organic series. 



It is, to say the least, a noteworthy thing that although these laws 

 constitute the true claim of chemistry to be called a science and are 

 moreover essentially quantitative in their character, practically no one 

 ever thinks it necessary to the laboratory study of chemistry that stu- 

 dents should carry out measurements looking toward even a rough 

 verification of these laws, nor has the writer heard that the most en- 

 thusiastic advocate of the heuristic method has ever cajoled a student 

 into thinking that he (the student) has discovered one of these laws 

 by himself. The real fact which makes the laboratory study of chem- 

 istry a totally different one from that of physics is that the student 

 meets even in the elementary stages a multitude of unfamiliar phe- 

 nomena which can best be comprehended and learned by individual 

 and intimate association with them, while there are altogether but two 

 or three quantitative experiments which are available. In physics, on 

 the other hand, the proportion is quite the reverse. The phenomena are, 

 for the beginner, simple and entirely familiar, especially in mechanics, 

 but the laws or quantitative relations are very numerous. Moreover, 

 the comparisons made by the chemical student are for the most part 

 qualitative in character; that is to say, they involve observation upon 

 such things as the formation of precipitate, the evolution of a gas, a 

 ready solubility or a change in color, and though the result may be 

 more or less the particular amount is of no consequence. It is for 

 this reason easy to arrange a laboratory course whose aim shall be to 

 acquaint the student with such reactions, and we accordingly find 

 him diligently employed in trying to find out what effect sulphuric 

 acid will have on barium chloride or what silver nitrate has done to 

 his fingers. 



