55 2 Analyses of Books. [September, 
through a minute hole pierced in cardboard. Hence he concludes 
that each such spot represents the effedt produced upon the retina 
of the eye by the incidence of a single separate ray of light. 
He thinks that the effedt produced by pressure on the outside of 
the eye-ball can only be obtained from within by a pull, and that 
when a single ray of light passes into the eye it makes itself 
manifest to our vision by exerting a pull upon the retina of the 
eye. Hence light is a pulling or attradtive force, opposed to heat 
as a pushing or repulsive force. 
The Boundaries of Religious Liberty and the Science-Doctrine of 
Modern Exploration of Nature .* By Gustav Friedrich. 
Leipzig ; Siegismund and Volkening. 
Let us confess it ; we were somewhat led astray by the title of 
this little book. We expedted an examination of the debateable 
land which lies between the borders of Religion and Science, and 
perhaps the suggestion of a modus vivendi which might put an 
end to certain unseemly and unedifying disputes. We find a 
discussion on the light which the modern classification and phi- 
losophy of Science has to throw upon the limits of religious 
freedom. It is obvious that into such questions as the modifica- 
tion or stridt execution of the “ May laws ” we cannot for a 
moment enter. 
But the author’s views on the classification and the dodtrine of 
the Sciences admit of being considered in our pages. “ The 
Sciences,” he writes, “ spring from the experience of daily life. 
Between that which they teach us concerning the nature of things 
and that which we experience in common life by our own con- 
templation there is no specific difference. The Sciences are, so 
to speak, merely a higher power ( potenz ) of common sense.” 
He establishes three classes — the experimental, the descriptive, 
and the spiritual (mental or moral) Sciences, concerned with law, 
politics, art, religion, history, &c. He forgets that as the 
boundary between experiment and observation is not of a hard- 
and-fast nature, so the sciences based on these two great methods 
of research cannot well be treated as decidedly distindt classes. 
His judgment on those who do not accept this dualism is suffi- 
ciently severe. In illustration of his way of thinking we quote 
from a Note on the Bibliography of Scientific Methodology the 
following : — “ Herbert Spencer’s ‘ Essay on the Classification of 
* DieGrenzen der Religions freiheit und die Wissenschaftslehre der heutigen 
Naturforschung. 
