CONTENTS. Vv 
NUMBER XXVIL 
Art, XIX.—Observations on the duration jot multiple char- 
acter of Flashes of Lightning; by Oapen N. Roop,._.. 163 
XX.—On the effects of Magnetization in Baka the Di- 
mensions of Iron, Steel and Bismuth bars; by ALFRED 
AYER. Part Ay ving wil Lat Baye tbe ed 170 
rt mrs REVERS Theories of Heat; by W. A. Saemoie 186 
Anarie —On the oo and papier eras in New Eng- 
and; by James. D. Dawa, co. . 2 ee 198 
anes sin | some new species a Fossils from the Primordial 
ede Potsdam group of Rensselaer county, N. Y.; by S. W. 
ORD, SS an ea oa es eels os ee ee 
XXV.—Discovery of a new Planet; by C. H. F. Perers,.._ 215 
SCIENTIFIC INTELLIGENCE. 
Chemistry and Physics. —lImproved aiaaeS, THORPE: Photographie repro- 
duction of Diffraction- ee Srromt, 216, 
nd Ni 
by J. D. erg rots stays Trains of bou rs, and on the tra ee rt of boulders 
to a level above that of their Paging by plies REED, 218.—Results of the 
Earth’s Contraction, by R. Mau 219.—On Ohio and thor Gas Wells, by 
“ S. NEWBERRY, 225 —Possil Birds ‘from the Cretaceous of North America, by 
ULL: The History of Balanoglossus and Tornaria, by A. AGassiz, 2°4.— 
Journal of Researches og Natural History and Gadkoter 9 of the Countries visited 
- during the voyage of H. M.S. Beagle round the world, Darwin: Note on the 
Dates of some of Prof. Cope’ 's recent Papers, by 0. C. MARSH, 235. 
Astronomy. neta = a Analysis in connection with the Spectrum 
of the Sun, Lookysr, 2 
gence.—Explorations west of _ neg meridian, 237. 
ro Sag pi tific Intelli. 
Tnsta of remarkably low temperature observed a w Haven, Conn., 
238 yer roe and Results of the Precipitation in Rain ae Snow in in the United 
of Ho a 
i a CARPENTER, 2 ‘International Scientific ve Barat 241 . _ 
Mary rie oa m4) —Rev. Adam Sed : James Henry 0: 
Matthew #. Maury: Prof. Macquorn Rankine, 242. 
Appendiz.—A new Planet, PETERS, 243, 
