i88o.] 
529 
Analyses of Books. 
stated in a few words. It is known that the rays of light come 
straight from the sun. If a burning-glass be held so that it 
fairly intercepts the sun’s rays, the foci of the concentrated rays 
of light and heat are identical under the glass. It is known that 
glass obstructs the passage of heat [!] and admits the passage of 
light. As the rays of heat and light must be reflected [should 
be, refracted] at the same angle to have the same foci, it is 
assumed [i.e., by the author] that they are moving in the same 
straight line, but in opposite directions.” Here is, in the first 
place, a grave error in fact. Glass does not obstruct the passage 
of radiant heat from incandescent bodies. Further, if Mr. Bland 
will take a powerful burning lens he will find that the intensity 
both of light and heat decreases pari passu , going from the focus 
towards the lens. This is what should happen if the light and 
heat move in the same direction, according to the common 
theory, and what should not happen if the light only passes 
through and is concentrated by the lens, whilst the heat arrives 
at the focus from the opposite side and is refracted and concen- 
trated by nobody knows what. 
We have not space to make any further extracts from this 
pamphlet. We think if the author would work for a few months 
in a good physical laboratory he would greatly alter his views. 
His manner of dealing with heat reminds us of Goethe’s re- 
searches in optics. 
Reports of the Mining Surveyors and Registrars of Victoria. 
For the Quarter ending September 30, 1879. Melbourne : 
J. Ferres. 
The total quantity of gold raised in the colony during the quarter 
has been 189,648 ozs. 14 dwts. 
An Appendix by the Government botanist, Baron F. von 
Mueller, consists of observations on new vegetable fossils of the 
auriferous drifts. 
Guide to the Geology of London and the Neighbourhood. By W. 
Whittaker, B.A., F.G.S. London : Longmans and Co., 
and E. Stanford. 
This pamphlet is an explanation of the Geological Survey-Map 
of “ London and its Environs,” and of the Geological Model of 
London in the Museum of Praaical Geology. The author points 
out two errors : that the u London Basin ” — so-called is deep 
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