vi CONTENTS. 
NUMBER XLVL 
Art, XXI.—Researches in Acoustics; by Arrrep M, Mayer, 241 
XXIL—On the Thermo electrical Properties of some Minerals 
ee _— varieties; by A. Scuraur and Epwarp §&. 
XXII. ae the Possible Periodic Changes of the Sun’s 
Apparent Diameter; by Smmon Newcoms and Epwarp 
Se EOLDMN Soe ee 268 
XXIV.—A New Calculating Machine; by GzrorcE B. Grant, 277 
XXV.—Researches on as Hexatomic compounds of Cobalt; 
ty WoLCOTT GIBHG, 665 coca soe oe ist 2 55S S 284 
VI.—The M athesiatiant and sme ccii comer State of the 
Physical Sciences; by Josepn Loverine,.-------.--.- 297 
SCIENTIFIC INTELLIGENCE. 
Chemistry and Physics. Pedi hoy Acid, nage y w, 309.—Ozone not produced 
by the oxidation of the essen al Oils, Kixzert, 3 ate op of the Copper-zine 
Couple on the chlorides of Ethylene and Ethylidens, GLADSTONE and TRIBE, 311. 
Geology ~ haga History.—Notes on the new edition of Mr. Darwin’s work on 
the Stru and Distribution of Coral Reefs (1874), by J. a a: tra ct 
Minaralosseal os carey “an er a of Dr. Gerard T: 
Contributions of G. vom Rath: Fifth Annu al gg a of the "Geological Survey 
of Indiana: Paleozoic Fo: er “ K. BILLINGS, 319.—Revision of the Gen 
and Species of the “Tuliper, by 5. G. BAKER, 320.—Asexual growth fro gic 
Prothallus of Pteris Cretica : some oo Botany of 8. Pacific Exploding 
Exp edition under ‘Adu Wilkes, 321. 
ila tifie Intelligence.— “aoe ial School of Mines, Colorado: Alex- 
ander Wilson: Sixth Annual Report . ae —— us, Beneficial other “f 
sects of the State of seni CY. —Half Hours with Insec 
british Association: Dana’s Manual or Bees 323 = Obelwary. Desh er 
Prof. Jeffries Wyman, 3 393, 
NUMBER XLVIL 
Arr. XXVIL—On the Number and Distribution of the 
Bright Fixed Stars; by B. A. GouLp, ....... 2 ga, 325 
XXVIII.—The Deportment of Titanium with reagents in Iron 
Ores containing Phosphoric Acid; by E. H. Bocarpus,- 334 
XXIX.— Experiments on the _— of Nitrogenous Si a 
Substances; by H. P. Arm 337 
XXX. —On the Molecular Best “of Similar ‘Compounds ; ‘by 
Frank Wiceimsworrs CLEARER, 5. <i> 2. - 340 
XXXI1. ck elation between the Barometric Gradient and the 
Velocity of the Wind; by WM. Frrret, ---------.... 343 
X XIL—Researches in Acoustics ; ; by Atrrep M. Mayer,. 362 
XXXII. eR as of Primitive Undulation; by Puy 
ARLE: CRABB( 5 Soy ot ee eS 366 
XXXIV.—On Sanpete Pseudomorphs, and other kinds, 
from the Tilly Foster Iron Mine, Putnam Co., New 
York; by James D. Dana. With plates VI and VI, - 371 
