78 
POrULAFt SCIENCE REVIEW. 
Mr. Casella's notes are very appropriate, and serve, with the matter in the 
Appendix, to bring the essay fully down to the present state of knowledge 
on the subject. This Appendix, by Mr. Strachan, is formed of articles on the 
Action of Aqueous Vapour on Radiant Heat, on Solar Radiation, on Ter- 
restrial Radiation, and on the Spectrum of Aqueous Vapour. The publishers 
have also issued the work in a handsome form, so that everything about it 
leads us to anticipate for it a rapid sale. 
MAUNDER’S TREASURY OF SCIENCE.* 
T HE present edition of Maunder’s Scientific Treasury has been thoroughly 
revised, and in great part rewritten, and has upwards of a thousand 
new articles added. As a Literary Treasury it has not much to recommend 
it, the literary articles being very few and far between. As a Scientific 
Treasury it is exceedingly good, and the editor, Mr. Yates Johnson, has, with 
considerable success, carried out his attempt to impart to the work an exact 
and scientific character, without diminishing its utility as a dictionary for 
popular reference. 
CONIC SECTIONS.! 
T HIS is a small treatise extending over only eighty or ninety pages, in- 
tended by the author as a first course of lessons and exercises, to prepare 
the young student for reading the treatises of Salmon, Hymes, Ruckle, and 
Todhunter. Treating only of the equations of the straight line, circle, and 
the other conic sections referred to rectangular co-ordinates, and of ele- 
mentary problems upon their curves, it is certainly simpler for acquisition 
than are the works which discuss the subject more comprehensively. It 
puts off, in fact, many of the difficulties of the subject for mastery by the 
student at a future day by means of other instruction. All that it contains 
appears to be plainly stated, and ought to be intelligible to students of 
ordinary capacity, though we are not satisfied that it possesses in this respect 
any marked advantage over the treatises of Puckle and Young. It has full 
claim to its title of u An Easy Introduction to Conic Sections.” 
* u The Scientific and Literary Treasury.” Ry Samuel Maunder. New 
Edition, by James Yates Johnson, Cor. M. Z.S. London: Longmans & Co. 
1866. 
t u An Easy Introduction to the Higher Treatises on the Conic Sections.” 
By the Rev. John Hunter, M.A. London : Longmans, 1868. 
