CONTENTS. 
Page 
Art, XXII.—Experimental Determination of Wave-Lengths 
in the Invisible Prismatic Spectrum; by 8. P. LANGLEY 
Crt eRe Ne eee apy oe ee 169 
XXITI.—The Quaternary Gravels of Northern fea are and 
Eastern Maryland; by F. D. Cugster. (With Map),.- 189 
XXIV.—On the identity of Seovillite with R baoweene: 
by G. J. Bausn an id 8. L. Penrter FORA NPE OC ae Ge TG 20 
XXV.—The Sun Glows ; by 1 A Agee ee ete 201 
oe I.—Topaz and associated Minerals at Stoneham, Me. ; ae 
PO wie es 212 
ee iL —Contribution to the Geology of Rhode Isiand ; by 
TN. Dare: (With a Map—Piate VIE... -. 2 217 
XXV TLL. —Crystalline Form ’ ee supposed Herderite from 
Stoneham, Mane; by Ree Diss, oo: as 229 
SCIENTIFIC INTELLIGENCE. 
Chemisiry and Physics.—Relation between the “mag Ww = of a: and 
-ooonl Magra oat Evapora tion, ScuAr1, 233.—Use of Nitrogen iodide in Pho 
metry, Production of Hydroxylamine ‘nt ‘Nitric sao evita 934. 
—Oxidutio tion b of F Phosphor us at low temperatures, Cowper and Lewes: Consti- 
tution of Benzene, KeEKULE, 235.—O} 54 servations on Phosphorescence, and a 
new phosphorescent eye- -piece, K. re MMEL, 236.—KEarth Currents, E. E. BLAVIER, 
237.—Heat in iron due to periodically pine nging m maar force, KE. WARBURG 
od L. Hote: Prit iciples of Thearet ical rigprsenell ith special reference 
o the Constitution of Chemical C Senne a {. Res 288. 
— y ~~ Pints toad a oe eee on sandstone nee? ae 0a in 
H, 
ive ages of certain River-valleys in 
Lineolnshi re, vy iy Fa ta N, $40: nn aS Seniieiane on oh ne Glacier 
and —— of Sorth Beds Malesia, OpvaRpO BECCART: tome oh 
Botanic oe , T. CarvenL, 241.—Necrologia Botanica, 242.— 
upon 
GEORGE * 
Astronomy and Mathematics—Double Star observations made in 1879 gt one 
with the 184-inch refractor of the Dearhorn pages uid Chicago, 8. W, BURN 
HAM, 244.—Treatise on Projections, T. Crat 
SMHiscelluneous. Scientific Pe. —Distribution of a Bet gt Declination in 
the United Srates at the poch Jan — ae “ sean Variatio n of. the 
Menetiv —— in ae Tnited etc 245.— Maps 
issued by the Northern gngeic esate Survey oy gc dat 246. 
Obituary.—ARSOLD Henry Guyor. 246, 
