Douglass, observations of Jupiter's satellites, [292]
Downing, perturbations of the Leonids, [338]
Draper, H., ultra-violet spectrum, [210];
oxygen in sun, [213]
photographs of the moon, [268]
of Jupiter's spectrum, [291]
of Tebbutt's comet, [354]
of spectrum of Vega, [382]
of Orion nebula [407]
Draper, J. W., lunar photographs, [152];
distribution of energy in spectrum, 223 note
Draper Memorial, [384]-386
Dreyer, Catalogue of Nebulæ,[ 50]
Dulong and Petit, law of radiation, [217] [219]
Dunér, spectra of sun-spots, [156];
spectroscopic measurement of solar rotation, [203]
spectroscopic star catalogue, [381]
Dunkin, solar translation,[ 39]
Duponchel, sun-spot period, [163]