Rosse, third Earl of, biographical sketch, [114];
great specula, [115]-117
discovery of spiral nebulæ, [118]
resolution of nebulæ, [119]
climate and telescopes, [434]

Rosse, fourth Earl of, experiments on lunar heat, [269]

Rost, nature of sun-spots,[ 54]

Roszel, mass of asteroids, [287]

Rowland, photographic maps of solar spectrum, [210] [440];
elements in run, [213]
concave gratings, [439] [440]

Rümker, observation of Encke's comet,[ 90]

Russell, H. C., red spot on Jupiter, [295];
change in Argo nebula, [404]
photographs of Nubeculæ, [425]
[Pg 485] photographs of Nubeculæ, [425]

Russell, H. N., atmosphere of Venus, [254]

Rutherfurd, lunar photography, [268];
star spectra, [372]
photographs of the Pleiades, [410]
diffraction gratings, [439]

Sabine, magnetic and sun-spot periods, [127] [128] [130]