i68 Analyses of Books. [March, 
studio, and secured the door on the outside, so that he did not — 
and could not — appear on the scene. Mr. B. Coleman, who 
was with us, and myself ( i.e ., Mr. Howitt), took the plates at 
hap-hazard from a dusty heap of such ; and Mr. Coleman went 
into the dark chamber with the photographer, and took every 
precaution that no tricks were played there.” 
Another writer here quoted justly remarks : — “ No photo- 
grapher can counterfeit the portrait of a deceased person un- 
known to him, and of whom no likeness exists. Yet this is what 
is done in Mr. Hudson’s studio.” Mr. Beattie (a retired photo- 
grapher) maintains that the luminous appearances seen by sen- 
sitives as issuing from magnets, crystals, &c., as in Baron Reich- 
enbach’s experiments, when condensed, affeCt prepared plates as 
energetically as does solar light. As regards the tests proposed 
Miss Houghton remarks naively that “ Scientific men are very 
exacting, and have no kind of compunction as to the labour and 
fatigue that their fancies may entail.” She should remember 
that they spare no labour or fatigue in testing their own results. 
The importance of testing these results to the uttermost 
cannot be gainsaid. A person may think he sees something 
non-existent. Several persons may fall into the same delusion. 
But we hold even the author of the phrase must admit that a 
photographic plate cannot be swayed by a “ Dominant Idea.” 
Miss Houghton’s book is inconveniently arranged. We do 
not find certain principles distinctly laid down and proved 
seriatim by experimental evidence. The plan of the book is 
historical with much repetition. Hence prolonged reading is 
required to sift out the phenomena alleged to have been wit- 
nessed from matter of a subjective nature. We trust, however, 
that we have not misinterpreted the author’s views. 
Physics of the Earth's Crust. By the Rev. Osmond Fisher, 
M.A., F.G.S. London : Macmillan and Co. 
We have here an important work by a valued contributor to the 
“Journal of Science.” The author has undertaken to answer 
certain problems in physical geology, “ negatively, if not posi- 
tively,” by the application of simple mathematical reasoning and 
quantitative treatment, and the results obtained, though admittedly 
approximate, are not merely of interest in themselves, but are 
calculated to draw further attention to the method, which has 
been here pursued. It must not be supposed, that the ques- 
tions here raised concern merely the physicist, the astronomer, 
or the geologist. An attempt has been made by an eminent 
