34 



SCIENCE. 



[N. S. Vol. XII. No. 



fore these problems can be satisfactorily 

 solved. 



In conclusion one word as to a very prac- 

 tical problem connected with this group. It 

 is but a few years past a century since the 

 use of platinum was introduced into the 

 chemical laboratory. For a few decades 

 the supply exceeded the demand, but the 

 applications of platinum have steadily in- 

 creased, and never so rapidly as in the last 

 two decades. For many purposes no sub- 

 stitute for platinum has been found. At 

 the same time the supply of platinum is not 

 keeping pace with the demand, and as a 

 result the price of platinum has very ma- 

 terially advanced. While platinum is very 

 widely distributed, there are few places 

 where it occurs in workable quantities. It 

 is possible, however, that it has been often 

 overlooked, as in placer mining for gold, 

 and efforts have been made to attract min- 

 ers' attention to more careful search for 

 platinum deposits. At the present outlook 

 it will, within a few years, be imperatively 

 necessary either to materially increase the 

 platinum supply of the world or to replace 

 it for many purposes by some other sub- 

 stance. How this problem will be solved 

 cannot now be foreseen. 



Jas. Lewis Howe. 

 Washington and Lee Univbesity. 



SCIENTIFIC BOOKS. 



The Elements of Physics for Use in High Schools. 



By Henry Crew, Ph.D., Professor of Physics 



in Northwestern University. New York, The 



Macmillan Company. 1899. Pp. 347. 



One of the most striking indications of the 



steadily increasing demand for instruction in 



science as a part of elementary education, is 



found in the periodic recurrence of new books 



on a market that would seem to have become 



already overcrowded. If the new competitor 



is written by one who manifests his possession 



of the teacher's instinct in addition to the 



scholar's knowledge, its reason for existence is 



quickly established. The author of the present 

 volume plainly shows himself to be the possessor 

 of both, though as a teacher he may have had 

 little experience in the grade of schools for 

 which his book is intended. In the preface he 

 expresses his obligations to one friend, a high 

 school teacher, ' for many important excisions 

 in the MS.,' and his readiness to have others 

 ' point out sins either of omission or of com- 

 mission.' 



In criticising such a book it is a pleasure to 

 find so little to condemn, even if a few more 

 excisions may seem advisable. Physics is es- 

 sentially applied mathematics, even when no 

 attempt is made to introduce openly the ideas 

 of calculus or even of trigonometry. It is most 

 natural therefore that a physicist, who is not 

 himself a high school teacher, should overesti- 

 mate the ability of the average high school 

 pupil to grasp mathematical conceptions that 

 are not usually introduced in the work of the 

 secondary school. 



In the introductory chapter on motion a brief 

 and clear exposition of vectors and scalars is 

 given, and a subsequent application is made in 

 the discussion of uniform motion in a circle, 

 where the position vector and velocity vector 

 are contrasted, and the nature of the path 

 deduced, along with the formula for acceleration 

 in terms of radius, angular velocity, and periodic 

 time. There is no theoretic objection to this, 

 but it is probably safe to predict that many 

 secondary pupils will agree in thinking the dis- 

 cussion much too abstract for them. Indeed it 

 would not be hard to find college juniors of 

 literary bent, who would be sympathetic with 

 their friends in the preparatory school, and who 

 would congratulate themselves on the absence 

 of problems, necessary as these may be to bring 

 home a difficult subject. There are fashions in 

 educational method as well as in dress. Whether 

 the vector analysis fashion can be maintained 

 in elementary schools may be doubted. To im- 

 mature students the method is certainly not so 

 easily grasped as are some other methods that 

 have hitherto been satisfactory to many. 



In the discussion of angular motion much 

 stress is laid upon the distinction between speed 

 and velocity, the former being a scalar and the 

 latter a vector quantity. This distinction has 



