2 Advertising Sheet of the 
all seasons. Mr. Espy has devoted many years to this subject, and 
has fortified his doctrine by a vast body of facts, which will be de- 
tailed in the present work in so simple a manner, as to be intelligi- 
ble without much previous mathematical knowledge. 
It is indeed intended to be eminently a practical work—useful to 
all classes of citizens, especially to the navigator. Espy does 
not come before the world with crude, unformed theories, but by a 
patient induction from facts, he brings out a beautiful system, which 
one of the most illustrious philosophical bodies in the world—the 
Institute of France, in a report on the subject says, “ satisfies alone 
the phenomena,” and moreover they declare that “ for physical ge- 
ography, agriculture, navigation, and meteorology, it gives us new 
explanations and useful indications for further researches, and cor- 
rects many prevailing errors. They also express the earnest desire 
that Mr. Espy may be put by the government of the United States 
in a position to pursue bis important labors, and to complete his 
theory, already so remarkable, by all the observations and expeti- 
ments which his deductions may suggest to him, in a vast country 
where enlightened men are not wanting to science, and which is, as 
it were, the native country of these formidable meteors.” 
r. Espy has lectured on this subject, not only in all the large 
cities of the United States, where he has been received with great 
favor, but he has visited Europe, and lectured to enthusiastic audi- 
ences formed of the most intelligent citizens in Liverpool, Manchester, 
er he is at sea or on land, while it has not yet approached within 
several hundred miles of him. Mr. Espy has permitted many such 
predictions to be published in Philadelphia even when the weather 
was clear there, and his predictions were always verified. 
Boston, October, 1841. 
Dr. J. R. CHILTON, 
PRACTICAL CHEMIST, &c., 
No, 263 Broapway, New York, 
Keeps constantly for sale at his establishment, a general assort- 
ment te pane. ape and Chemical Apparatus, Chemical Prepara- 
lions, every thing necesssary for the study of Chemistry a9 
a branches of Natural Philosophy—among which are the fol 
8800 ae 
