210 Miscellanies. * 
and is very pure. The column rises from a source one third of a mile 
below ground, and it spouts thirty feet above the surface. The tempera- 
ture at the bottom of the boring* was nearly 83° of Fahrenheit, (that of a 
hot summer’s day, such as is rarely known there on the surface,) thus 
confirming fully the increase of heat in the interior of the earth, by 
the average generally observed in similar cases of about 1° for fifty feet 
of descent, which, at the same rate of increase, would give a fountain of 
boiling water at two miles from the surface—full ignition of rocks at ten 
miles, and fusion at two hundred miles ; thus leaving a firm crust to pre-” 
serve the good citizens of Paris from being disturbed by the fear of 
breaking through, or by the danger of the immediate outburst of the fire. 
20. The Theory of Horticulture: or an attempt to explain the princi- 
pal operations of Gardening upon Physiological Principles ; by Joun 
Linvury, Ph. D. F.R.S., &c. &c. First American edition, with notes, 
&c., by A. J. Downie and A. Gray. New York, Wiley and Patnam. 
Boston, C. C. Little and Co. 1841.—Few authors, at least in the En- 
glish language, have been equally successful with Dr. Lindley in render- 
ing real science intelligible and attractive to the general reader. This 
work, “ written in the hope of providing the intelligent gardener, and the 
scientific amateur, correctly, with the rationalia of the more important 
operations of horticulture,” has supplied a very important desideratum, 
and is deemed indispensable to every gardener and amateur cultivator 1 
Great Britain. We presume it will be equally prized in this country, 
where a taste for horticulture is so widely diffused, and where @ work, 
which conveys this kind of information, is so greatly needed. This edi- 
tion is very neatly printed in the 12mo. form, and is afforded at an e© 
tremely moderate price. sos 
21. Corresponding Magnetic Observations, by Prof. A. D. Bache of 
Philadelphia, and Prof. Lloyd of Dublin.—It is with much pleasure 
that we republish from the Proceedings of the Royal Irish Academy, (for 
June 22, 1840,) the following account,+ by Prof. Lloyd, of Dublin, of 4 
series of simultaneous magnetic observations made in November, 15%; 
by Prof. Bache at Philadelphia, and Prof. Lloyd at Dublin, with a view t 
determine whether any deductions could be drawn from them for deter- 
mining differences of longitude. The results are very satisfactory, 124° 
much as they prove definitely that “‘no correspondence whatever exists 
between the smaller changes of declination at Dublin and at Philadel- 
phia, and that the determination of differences of longitude by means of 
. 
the magnet at such distances is impracticable.”—Eps. 
: * Which is over eighteen inches wide at the top, and from seven to eight at the 
bottom, and lined with a metallic tube. 
t This account has been slightly abridged, to accomntnodate it to the crowded 
a — - Seat — daha 
State of our pages.—Eps. 
