1879.] 
643 
Notices of Books . 
tions of the moon before 1750. An historical introduction is 
followed by an account of various ancient eclipses of the sun 
and moon, beginning with the eclipse of Thales, passing on to 
the Ptolemaic eclipses of the moon recorded in the Almagest, 
and the Arabian observations, as given in the writings of Ebu 
Gounis. These are followed by the observations of Bullialdus, 
Gassendus, and Hevelius, and the astronomers of the French 
School before 1750. A technical mathematical discussion of the 
moon’s mean motion and of the value of the secular acceleration 
concludes this portion of a work which will be welcomed by 
astronomers in every part of the world. 
A Treatise in Popular Language on the Solar Illumination of 
the Solar System. By Collyns Simon. Williams and 
Norgate. 1879. 
The contents of this work is so very fully set forth in the title 
page, and we can have so little to say to such a treatise, that we 
confine our notice to a transcript of the title page : — ■“ The solar 
illumination of the solar system, or the law and theory of the 
inverse squares ; being an analysis of the two received laws 
relating to the diminution of light by distance, wherein it is 
shown that, according to undisputed faCts of nature and of 
science, the solar illumination is equal throughout the whole 
system, and the law of inverse squares for light, physically im- 
possible. To which is added the prospectus for a prize of fifty 
guineas offered for disproof of the scientific faCts here for the 
first time indicated.” 
In the same category we must place Mr. Orson Pratt’s “ Key 
to the Universe, or a new theory of its mechanism founded 
upon a continuous orbital propulsion, arising from the velocity 
of gravity and its consequent aberrations, and the resisting 
ethereal medium of variable density.” 
Dreams of my Solitude on the Mysteries of the Heavens . By 
Joshua Prusol. London: Reeves and Turner. 1879. 
This work, of a severely essaic type, may commend itself to 
certain dreamers who are not au courant with the courses and 
ways of modern science. Although highly imaginative, it is not 
devoid of profound thought, and we cannot too highly praise the 
singular modesty of the preface ; specially of the concluding 
sentence, in which the author says, “ Dear, naturally, as these 
