Letters, Extracts, Notices, ^c. 315 



The distance from the observer of the birds that cross the 

 moon's disk not being known, the problem of computing the 

 height at which they fly is not accurately determinable. But 

 assuming, as may be reasonably done, that the crossing 

 birds are at least one mile distant, and, in all probability, 

 not more than five miles, the approximate height at which 

 they travel may be calculated within certain limits. Of 

 these heights Mr. Chapman has given us a table, showing 

 that they vary from 600 to 15,100 feet in different cases. 

 But further observations are required on this subject before 

 much reliance can be placed on the results thus obtained. 

 The number of the birds passing the field of view in a given 

 time is also a subject of great importance upon which further 

 information is wanted. On the whole it may be confidently 

 stated that here is a practical scheme for obtaining much 

 fresh information on the interesting subject of migration 

 open to any one to whom the use of a good telescope at the 

 migratory period is available. 



Winter-birds in Spitsbergen. — It appears from Mr. Arnold 

 Pike's diary, lately published in Mr. Abel Chapman's ' Wild 

 Norway,' that even in Spitsbergen, where the sun does not 

 rise above the horizon for nearly four months, individuals 

 of at least four species of birds are found throughout this 

 season. Mr. Pike, who passed the winter of 1888-89 in 

 Dane's Gat, near Amsterdam Island (79° N. lat.), states 

 that he saw " Tysties " on January lltli, and heard Eiders 

 and Guillemots " crying and diving close inshore." On 

 February 10th '' Ryper's " droppings were observed. The 

 Spitsbergen Grouse, Mr. Pike says, make long burrows in 

 the snow, and thus reach the autumnal crop of berries and 

 seeds stored up beneath its surface. We may therefore put 

 down four species of birds as remaining in Spitsbergen 

 throughout the winter : — Lagopus hemileucurus, Uria mandti, 

 Uria bruennichi, and Somateria inollissima. To these, perhaps, 

 the Fulmar [Fulmarus glacialis) should be added ; at any 

 rate, it was observed on February 20th, the day on which the 

 sun was first seen at noon. 



