Vi ; CONTENTS. 
Botany and Zoology. ~-Monographize Phienogamarum, DECANDOLLE, 235.-—Arbo 
retum Segrezianum, A. LAVAULEE, 238.-—Bri Moss-Flora, R. BRAITHWAITE: 
Butterflies, their Structure, Changes and Life histories, S. H. ScupDER, 239. 
Misscellaneous Scientific Intelligence.—Meeting of the American Association for the 
elegr: 
Exact Sciences, Biographical ee Literary, OdGENDORFF: gr anes a Re 
Cotton Production of the State of Louisiana, E. W. hird 
Bress aie Academy of Turin, open to Scientists aiid riveutcre pe ‘at Na- 
tions, 
NUMBER CXXxX. 
Page 
Art. XXX V.—Cause of the Arid eieete of the Western por- 
tion of the, United, States; by C. E. Durron,__.-_----- 247 
XXXVI.—Embryonic Forms of Trilobites from the Primor- 
iat ocks of Troy, NN. ¥.;-by 5. .W. Vorb, ...-- ..-..- 250 
XX XVII.—Observations of Comet 6, 1881; by E S. HotpEN, 260 
XXXVITII. a of the Ice-sheet at any Latitude; by 
ee ee 264 
XXXIX. eae Or err Sonn Mienoen, vo kk 268 
XL.—Notes on Earthquakes; by C. G. Rocxwoop,._-.___- 289 
XLI.—Marine Fauna occupying the outer aris off the 
Southern coast of New England; by A. ERRILL,... 292 
XLII.—Note on the Tail of Comet 6, 1881; by Lewis Boss. 
Meee intes V ht VE eee 303 
LHL XLIV. —Geological Relations of the Limestone Belts 
of Westchester Co., New York; by Jamus D. Dana, 313, 327 
SCIENTIFIC INTELLIGENCE. 
Chemistry and Physics. —Velocity of Light, RALEIGH: Movement of Sound Waves 
in Organ Pipes, R. K@ : Conduct ctivity of Metals for Heat and Electricity, 
LORENZ, S18 Miceophunis ‘action of Selenium cells, J. MosER: Stresses cause 
_ in the Interior of the Earth by the Weight of Continents and Mountains, G. 
appt a 2 age ass of Cast Iron while solidifying, M. J. B. HANNAY and 
R 
sche « and Wades cree —Origin of the — Ores of the Marquette District, 
Lake uperio r, M. E. WapswortH, 320.—Taconie rocks of the border of 
Oo 
in Goshen in Northwestern Connecticut: Structure and Affinities of the 
Monticulipora ri its poe pie , H. A. Nice sao a 322 —Ulesite in Califor 
nia. BLA 
R —F 
von Neapel, So-ms-LavBacn, 326.—Botanical Collector’s Handbook, W. 
BAILEY, 326 
—— Scientific Intelligence.—Ancient Japanese Bronze Bells, E. 8. MORSE, 
326, . 
