iv CONTENTS. 
Page. 
XV. Axial Galvanometer, and Double Axial area 
Engine; by Prof. Cuarues G. Pace, - . 136 
XVI. Report of Observations on the Transit of Mercury, May 
8th, 1845; by Prof. OumsTeD, - - - - 142 
XVII. Bibliographical Notices :—Narrative of the United States 
Exploring Expedition during the years 1888, 1839, 1840, 
1841, 1842. By Cuartes Witxss, U. S. N., 149.— 
Prof. W. R. Jonson on the Heating Power of various 
Coals, 166.—Musée Botanique de M. Bensamin DE.zs- 
sErT; Notices sur les collections de Plantes et la Bibli- 
othéque qui le composent ; contenant en outre des docu- 
ments sur les principaux herbiers d’Europe; par A. La- 
SEGUE, 171.—De Candolle’s Prodromus, Vol. 9, 174.— 
De Candolle’s Theorie elementaire de la Botanique, 
175.—Fifty Eighth Annual Report of the Regents of the 
University of the State of New York, 176.—Report of 
Experiments on Gunpowder, made at Washington Ar- 
senal, in 1843 and 1844; by Capt. Atrrep Morpscat, 
180.—Rural Economy in its relations with Chemistry, 
Physics, and Meteorology : or Chemistry applied to Ag- 
riculture; by J. B. Bousstncautt, 182.—Proceedings 
of the Academy of Natural Sciences of Philadelphia, 
183.—Mulder’s Chemistry of Vegetable and Animal 
Physiology, American Edition, 186.—Life of Godfrey 
William Von Leibnitz; by Jonn M. Macxis, 187.— 
Wiley & Putnam’s Catalogue of Scientific Books: Li- 
brary of Choice Reading: Handworterbuch der 'Topo- 
eraphischen Mineralogie von Gustav Leonuarp, 188.— 
The Botanical Text Book, for Colleges, Schools and Pri- 
vate Students; by Asa Gray, M. D., 189.—A Class 
Book of Botany, designed for Colleges, Academies and 
other Seminaries ; by AupHonso Woop, A. M.: Owen’s 
Illustrated Catalogue, 190.—Vestiges of the Natural His- 
tory of Creation: Dr. G. A. Manrett on the Geological 
Structure of the Country seen from Leith Hill in the 
county of Surrey, 191. 
MiscELLANIES.—Abstracts of the Researches of European Chem- 
y ists; prepared for this Journal by J. L. Smiru, M. D., 192.— 
New Instrument for the solidification of Carbonic Acid, 206.— 
