al OcToBER 16, 1913]| 
NATURE 
195 
These experiments have been repeated and con- 
firmed by other workers. 
Further, attempts to reproduce the disease by 
‘inoculation of artificial cultures have been suc- 
cessful. The authors have also carried out a 
considerable number of experiments with the view 
of obtaining a preparation of Johne’s bacillus 
suitable for diagnostic purposes on the same lines 
as those on which the tuberculin test is at present 
applied. The results have been distinctly encour- 
aging, and we may express the hope that lack of 
funds may not impede the further effective prose- 
cution of the author’s researches. The book has 
been very carefully written throughout, and con- 
cludes with a valuable bibliography. To all scien- 
tific veterinarians and stockbreeders this mono- 
graph may be heartily recommended. 
MATHEMATICAL TEXT-BOOKS. 
(1) Elementary Algebra. By C. Godfrey and 
A. W. Siddons. Vol. ii. Pp. xi+227-530+ 
xlvi. (Cambridge University Press, 1913.) 
Price 2s. 6d. 
(2) Four-Figure Tables. By C. Godfrey and 
A. W. Siddons. Pp. 40. (Cambridge University 
Press, 1913.) Price od. net. 
(3) Papers Set in the Mathematical Tripos, Part 
I., in the University of Cambridge, 1908-1912. 
Pp. 70. (Cambridge University Press, 1913.) 
Price 2s. 6d. net. 
(4) Elementary Experimental 
Schools. By C. E. Ashford. 
Dynamics for 
Pp. viii+ 246. 
(Cambridge University Press, 1913.) Price 4s. | 
(5) Mathematics, Science, and Drawing for the 
Preliminary Technical Course. By L. J. Castle. 
Pp. vii+149. (London: George Routledge and 
Sons, Ltd., 1913.) Price 15s. net. 
(6) Nomography, or the Graphic Representation 
of Formulae. By Captain R. K. Hezlet. Pp. 
iv+54. (Woolwich: Royal Artillery Institu- 
tion, 1913.) Price 2s. 6d. 
(7) The Principles of Projective Geometry Applied 
to the Straight Line and Conic. By J. L. S. 
Hatton. Pp. x+366. (Cambridge University 
Press, 1913.) Price 1os. 6d. 
(1) HE second volume of this treatise, which 
is intended to include as much as the 
pupil of average ability will assimilate in a full 
school course, opens with a treatment of indices 
and logarithms. The next two chapters deal with 
variation of functions of one or more variables. 
This is followed by harder equations, surds, pro- 
portion, and progressions. The next four chapters 
contain an excellent introduction to the differential 
and integral calculus. Although confining them- 
selves to very simple functions, x®, x3, 1/x, the 
NO. 2294, VOL. 92] 
authors have illustrated all the important ideas of 
the subject. The educational value of such work 
as this is very great, and we have little doubt 
that in a few years’ time it will be accepted as 
a regular part of the non-specialist course. This 
and the chapter on progressions are the outstand- 
ing features of a book which is admirable through- 
out. An appendix is added containing such parts 
of the subject as are still required by various con- 
servative examining bodies, but which the authors 
hope further reform will soon render unnecessary. 
There is an excellent set of test papers. 
(2) We welcome the issue of this set of four- 
figure tables chiefly on account of their low price. 
Now that their use has become so general, it is 
important that students should be able to procure 
them in an inexpensive form. There is little to 
note in regard to their contents, which include, in 
addition to squares, square-roots, reciprocals and 
logarithms, the usual trigonometrical tables. In 
our opinion it is unfortunate that the table of 
logarithms is not placed at the beginning. Coming 
as it does at p. 22, some time will always be lost 
in finding it. The arrangement of. the table of 
square-roots is new and distinctly ingenious; for 
instance, opposite to 42, printed one below the 
other are the numbers 2049, 6481, thus making 
it impossible for the pupil to take the square-root 
from the wrong page. 
(3) This collection of papers, set under the new 
regulations for the first part of the mathematical 
tripos, besides being of use to undergraduates at 
Cambridge, is interesting as showing the change 
in character of the work required from candidates 
for honours since the abolition of the order of 
merit. The ten-minute conundrum has now prac- 
tically disappeared, and its place taken by more 
practical and straightforward - questions. With 
the exception of some electricity and optics, there 
is practically nothing that the capable specialist 
would not be able to do on leaving school, and the 
course, therefore, suits not only those who are 
intending to take up research work, but also 
those who will afterwards turn to mechanical 
science, engineering, or physics. 
(4) The use of a trolley and inclined plane has 
done much to smooth away the difficulties from 
the path of those who attempt an experimental 
introduction to dynamics. Most teachers now 
agree that it is unsatisfactory to allow the ordinary 
student to confine himself to a theoretical treat- 
ment. Mr. Ashford quotes from Thomson and 
Tait’s standard treatise a remark that “ Nothing 
can be more fatal to progress than a too confident 
reliance on mathematical symbols, for the student 
is only too apt to consider the formula, and not 
the fact, as the physical reality.” And he has set 
