Feb. 9, 1882] 
from the printed page, and all other white paper lying on 
the table, dries the eyes, the lids, the forehead, and 
temples, Temporary relief may be found by bathing the 
face and eyes in water, but it is only temporary. The 
hot, dry air about the lamp is also harmful, and no doubt 
contributes its share of injury to the vision. These evils 
may both in part be remedied by placing a pane of glass 
so as to intercept the rays from the lamp before they 
strike on the book or the face. But it must be placed at 
such a distance from the lamp as not itself to become 
heated. 
The hotter the flame, the whiter it is, and the more 
light is thrown off in proportion to the heat. Hence 
oculists are recommending such lights as the Student's 
and Moderator lamps, which burn with a small, hot, and 
very brilliant flame, as compared with that furnished by 
THE GREAT NEBULA IN ANDROMEDA 
tel objects in the heavens have been treated with 
such unmerited neglect as this which has not inaptly 
been termed the Queen of the Nebula. Notwithstanding 
NATURE 
341 
the Argand and fish-tail burners, We learn from statistics 
how alarmingly prevalent near-sightedness has become of 
late among students. Hence anything which will tend in 
the future to prevent this wide-spread defect will be a 
boon to mankind. And here is where the particular ad- 
vantages of electricity come to the front. The fact that 
there are no gaseous products to radiate heat without 
light, taken together with the high temperature of the in- 
candescent carbon, unite to give us the maximum of light 
with the minimum of heat. ‘The ever-varying intensity of 
the arc light is at present a strong objection to it, but we 
may look forward to the success of the light from the 
incandescent carbon strip, in the near future, with the 
assurance that we shall soon have a remedy for the most 
wide-spread evil that afflicts the human vision. 
Boston, Mass., U.S.A. W. H. PICKERING 
its enormous magnitude, spreading out, as followed by 
the Harvard 15-inch achromatic, to 2}° in length, (ac- 
cording to Bond—Trouvelot gives more), with a breadth 
of upwards of 1°; and its conspicuous brightness, readily 
perceptible with the naked eye, it has received little com- 
Fic. 1.—Bond, 1847. 
parative notice. The reason probably may be the per- 
tinacity with which it has hitherto resisted all inquiry, 
and defied the efforts of the most powerfully armed inves- 
tigation ; so that it seems to have been left on one side, 
as too unpromising for more than casual inspection. 
This however bears the character of a premature con- 
clusion. Direct examination by the most powerful tele- 
scopes has done very little to solve the mystery of its 
nature. The reply extorted by the spectroscope is but 
partially intelligible. But we must not therefore despond 
