PACE AND LAST 115 
night. The eyepiece of each telescope was crossed 
by hairs that divided the field into “‘ octants,’’ and 
each observer had a chart of the moon divided into 
corresponding octants. When a bird appeared in 
the area covered by both telescopes, its course across 
the face of the moon was immediately marked on the 
charts by straight lines, and the hour noted. The 
bird, in fact, had the honour of being treated as a 
star; the angle at the bird subtended by the line 
between the two observers was calculated; a 
parallax was obtained, and very fairly accurate 
calculations were made. In May no bird was 
observed flying at more than 2,400 feet (less than 
half a mile) above the ground ; the lowest was flying 
at a height of 1,200 feet. In October the birds 
ranged from 5,400 feet (over a mile) down to 1,400 
feet. The calls of birds not far overhead were heard 
frequently during the observations, and Mr. Car- 
penter remarks that, probably, most flew lower than 
those observed through the telescopes. I don’t 
understand this, since Mr. Carpenter says that 
objects as near as 1,000 feet were distinctly visible. 
If so, why did the low-flying birds not come into 
view ? 
It is quite possible, then, that migrant birds get 
much assistance from the wind. Though they often 
fly in such a direction that our low-level wind would 
strike upon their shoulder or even blow straight in 
their faces, yet a higher current may be shoving them 
onward, for they fly at an altitude up to which it 
frequently happens that the wind that sweeps over 
the earth’s surface does not extend. Is it not 
possible that Homing Pigeons, though they fly lower 
ihz2 
