81 8 Notices respecting JYew Books. 



this locality is due to the solution of radium emanation as 

 the water percolates through the soil. When the water 

 trickles rapidly through the upper layers, a large amount 

 of emanation is dissolved in the water. A " wet weather " 

 spring on the campus of Indiana University measured about 

 2000 x 10~ 12 curie a short time after a very heavy rainfall. 



Dept. of Physics, 

 Indiana University, 

 Jnly 27, 1915. 



LXXXVIIL Notices respecting JSfew Books, 



The Teaching of Algebra ; and Exercises in Algebra, including 

 Trigonometry, Parts I., II. By T. Peecy. JNtjnn, M.A., D.Sc, 

 Professor of Education in the University of London, etc., 

 Longman?, Green & Co: 1913-1914. Pp. xiv+616; x + 356 

 xi-f-551. Price 7s. 6d. ; 4s., 6s. 6cl. 

 r JTHE first of these three volumes, constituting part of 'Longmans' 

 -■■ Modern Mathematical Series,' is intended as a practical hand- 

 book for the teacher, and the two Parts of the " Exercises " for the 

 pupil, although the selection of exercises for actual use will have 

 to be guided to a certain extent by the teacher. The author's 

 opinion is that " Algebra " should include " all the Trigonometry, 

 together with an exposition of the fundamentals of the Calculus." 

 He presents, therefore, both these subjects, in the " Teaching " as 

 well as in the "Exercises," and does it in such a lucid, easy, 

 and, at the same time, critical manner, that even the average 

 beginner will be able to follow, with much interest and without 

 straining his natural faculties, the whole course based upon these 

 lines. The attainment of such a result presupposes, of course, a 

 somewhat enthusiastic and subtly intelligent teacher. But what 

 imaginable course of teaching (of any subject, and more especially 

 of mathematics) does not presuppose such qualities in the teacher? 

 This being granted, Prof. JSTunn's book should prove to become one 

 of great utility for secondary schools. It is apt, moreover, to 

 bring about a very desirable reform in the programme of the 

 public examining bodies, " which exercise such immense influence 

 upon mathematical teaching in this country." As such especially 

 can Dr. Nunn's careful and inspired work be warmly recommended 

 to all, and, in particular, to the younger and more courageous 

 teachers of elementary mathematics. 



