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POPULAR SCIENCE REVIEW. 
They defeat what appears to us to be their author’s most laudable 
object, namely, to secure to all men freedom of thought and expression on 
scientific matters ; for in trespassing so rudely and inconsiderately beyond 
the limits of scientific inquiry, and indulging in wild speculations, he 
rather impedes than facilitates the progress of Truth. 
Let us remind him, that if the organ of speech had been man’s chief 
characteristic, he would not have been what he is. Guided by tradition 
alone, the multitude would have heard with satisfaction of an auto-da-fe 
in Jermyn Street, and no scientific inquirer would have been hereafter safe 
from martyrdom. 
But are not such doctrines as we find in this work calculated to justify 
intolerance? Do they not give a colouring of justice to the anathemas 
which are, from time to time, launched against free scientific inquiry ? 
We think they do, and our readers must decide for themselves. 
If, then, it be the desire of the author and others (for he is net the 
only one to whom we could refer, who, under the guise of an iconoclast 
appears to throw doubt upon the evidences of design, and upon the all- 
pervading influence of a First Cause, in every natural phenomenon) — if, we 
say, it be the desire of the author, and others holding a high position in 
the scientific world, to see the veil of superstition withdrawn from human 
eyes, and the reign of reason ushered in, we recommend them to let the 
“ scalpel ” alone, and to allow the force of reason to burst the larval 
investiture of the age. He. who teaches the insect to free itself from the 
pupa-case, will, at the proper time , aid mankind in its efforts in the same 
direction. 
This operation the author can most effectively facilitate, by pushing on in 
his admirable and careful physical investigations, without importing into 
his works speculative theories and doctrines which have all the imperfec - 
tions, without any of the moral excellences of those “ superstitions ” that 
they seek to supplant — dogmas which possess neither the recommendation 
of convincing the reason, nor of appealing to the heart. 
Heat considered as a Mode of Motion. By Du. J. Tyndall, F.R.S. 
T HE author of this excellent and interesting book states at the outset 
that he has in it “endeavoured to bring the rudiments of a new 
philosophy within the reach of a person of ordinary intelligence and 
culture.” This statement is, we think, open to some explanation or 
correction with respect to the phrase “ a new philosophy,” especially as it 
is placed at the very outset of the work. The phrase manifestly refers 
to the view that heat is “ a mode of motion.” 
To persons unacquainted with the present literature of the science of 
heat, or of the physical forces in general, such a view may perhaps be 
new; but to those who have perused the writings of Faraday, or par- 
ticularly Grove, in his well-known work on “The Correlationof the Physical 
Forces,” or of Helmholtz, Carpenter, and various other writers on the 
physical forces, heat, &c., such a view is not new, being abundantly and 
