88 L. Trouvelot—Moon's Zodiacal Light. 
this did not seem to affect the position of the flame on the spec- 
trum. 
Cambridge, January 12, 1877. 
_ Art. XIL—The Moon's Zodiacal Light ; by L. Trouvenor. 
Durine the evening of April 3, 1874, the “ Zodiacal Light’ 
was particularly brilliant; especially close to the horizon, where 
it appeared as a segment of a circle, having an irregular wavy 
outline, giving it a vague resemblance to the beams of a faint 
aurora. Although the sky was clear, it was found impossible 
to observe with the telescope on that night, on account of the 
great disturbance of the atmosphere. At 9» 45™, the declina- 
tion needle indicated a very strong magnetic perturbation in 
Cambridge, oscillating through an angle of 3° 22’. However, 
no aurora was visible at this time, although the phenomena 
usually attending them were manifested during the evening by 
the tremulous appearance of the telescopic images. 
ile going home, I remarked in the east a strange conical 
light rising obliquely from the top of the roof of a building, 
behind which the moon, then about 15° or 20° above the 
utes, when it gradually faded away until it almost totally dis- 
appea ve minutes later, although the sky was clear. A 
quarter of an hour after, the sky was overcast with dense 
yapors, which continued for nearly an hour. © 
- At 11 Om the sky had cleared up, and the moon shone 
brightly. The luminous appendage was still visible, and even 
appeared more brilliant than before. In order to ascertain 
