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 



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