118 Notices respecting New Bcols. 



It will be seen that the refractive power of fused quartz is 

 very low ; its dispersive power is the same as that of crystal- 

 line quartz. The material is perfectly transparent, it works 

 as pleasantly as the crystal, and is certainly more permanent 

 than any glass. Perhaps the makers of microscope-objectives 

 might find it of some use. Examined by polarized light the 

 prism appears isotropic. 



C. V. Boys. 



South Kensington. 



IX. Notices respecting New Books. 



A Short Course of Experiments in Physical Measurements. By 

 Ha bold Whiting, Instructor in Physics at Harvard University. 

 — Part I. Density, Heat, Light and Sound. 



HPHE above volume is issued as the first portion of an Elementary 

 Course of Practical Physics, and deals with the subject in a 

 manner differing somewhat from that adopted in the ordinary 

 English text-books. The line of teaching indicated in it is one 

 which has been more extensively followed in Germany than in the 

 English colleges. 



The author has chosen for his purpose only such experiments as 

 can be performed without very elaborate apparatus, but which by 

 applying care and a few special precautions can be made to give 

 fairly accurate results. At the outset the student is expected to 

 acquaint himself with the chief sources of error in any determina- 

 tion, and to learn how these can be got rid of either by careful 

 manipulation or by suitable correction. He is thus taught at the 

 very beginning of his course to attach more importance to his own 

 carefulness than to the possession of what is often only apparently 

 more accurate apparatus. In some respects this system possesses 

 an advantage over the ordinary method of teaching, in which the 

 student's first course of practical physics usually consists in repeat- 

 ing for himself the experiments which he has seen performed in 

 the lecture-room. At the same time some difficulties arise from 

 the fact that the methods of correction often involve a greater 

 knowledge of physics than the student is supposed to possess when 

 he performs the experiment. A good instance of this is to be 

 found in the case of calorimetric measurements, where the appli- 

 cation of a correction for the rate of cooling of a calorimeter in- 

 volves an acquaintance with the laws of cooling ; and these laws 

 would scarcely be treated of in an elementary course of lectures. 



But perhaps the difference in the systems of examination fur- 

 nishes the greatest objection to the adoption of foreign methods of 

 teaching. At the end of his first year's course an English student 

 is expected to know how to use almost every piece of apparatus 

 which he has seen exhibited in the lecture-room, and he is thus 



