340 Analysis of Scientific Books. 
Of the next essay, “ On the Construction and Uses of a New 
Hygrometer,” we shall say but little ; the ingenious ideas which led 
to its adoption: its mechanism and uses have been already detailed 
in this Journal, by the author, and the practical observations made 
with it in different portions of the globe, communicated by different 
scientific individuals through the same channel. To those, however, 
who have not perused Mr. Daniell’s description of the instrument, 
the essay before us will afford every necessary information regarding 
its construction, and mode of employment. 
The author complains, and not without justice, of the difficulties 
experienced in * approaching the shrines whence the oracles of 
science are issued,” and relates the following anecdote which we 
wish were unique: unfortunately, it is not the first instance by many 
where obstructions have been experienced in the fair investigation of 
philosophical discoveries by the academy in question, and frequently, 
we fear, from an overweening desire to promulgate the discoveries 
of their countrymen, and a corresponding apathy towards those of 
other nations. 
« Being actuated,” says Mr. Daniell, ‘* by the wish to obtain 
contemporaneous observations, and to do all in my power to facili- 
tate so desirable an object, and my own opinion being confirmed by 
those whose judgment I could not doubt, I took an opportunity of 
sending by a private hand, two of the hygrometers, in their most 
perfect state, to one of the philosophers of the French Royal Aca- 
demy of Sciences, the most distinguished for chemical knowledge 
and discoveries. I requested his opinion of the merits of the instru- 
ment, and authorized him to present one of them, in the most:-re- 
spectful way to the Academy. My presumption has, I suppose, been 
P operly checked, by no notice whatever having been taken of what 
was certainly meant as a mark of humble respect, either by the in- 
dividual, or the learned body: to the former of whom, having had 
the advantage of a personal introduction, I cannot feel that I have 
been to blame in addressing myself, however small may have been 
my pretensions for obtruding myself upon the latter.” P. 185. 
The next essay to which we shall advert, comprises a dissertation 
on the climate of London ; a subject not less interesting to the lover 
of meteorology as a science, than to the physician; there are, 
however, so many circumstances independently of the exact con- 
dition of the atmosphere as. regards temperature and dryuess, 
which exert a baneful influence over human health, that these phe- 
nomena are not so decisive in the study of causation as might @ priore 
be imagined : it has indeed been asserted by some philosophers that 
the greater salubrity of one country over another is principally owing 
to the lesser degree of noxious emanations from its soil ; and Heberden, 
Blane, and others, have affirmed that on the whole, except in the 
case of extraordinarily cold winters, the fluctuations of the weather in 
this climate do not much affect health, Still epidemics do occur, 
