ALTITUDE AND SPEED OF FLIGHT 



them a rapidity of about 55 miles was maintained 

 for four hours in succession. This view is largely 

 borne out by an investigation of the figures given 

 week by week in ' ' The Racing Pigeon " and other 

 journals of this character. As a first-class 

 homing Antwerp flies at an unquestionably greater 

 rate than any of the crow family, we can but 

 conclude that Gatke's figures are considerably 

 wide of the mark. 



Earlier observations thus may be taken to be 

 more or less guess-work, opinions being derived 

 from the relation of flying birds to trains travelling 

 at express speed and so forth. Again, birds, like 

 all living creatures, have different rates of speed 

 at different times — a sparrow, for instance, en- 

 deavourmg to escape from a hawk will accelerate 

 its speed far beyond the normal — and it is of course 

 the normal, unhurried rate of progress that one 

 desires to ascertain. 



Dr. Eagle Clarke, in his recent work " Studies 

 in Bird Migration," has pointed out that the 

 data on which the estimates were based were 

 of the flimsiest nature and has expressed his 

 belief that no species on migration (when the 

 speed may be taken as normal) exceeds 100 miles 

 an hour and that few reach anything like it, an 

 opinion now fully confirmed. 



In the " Ibis" (April, 1921) Colonel Meinertz- 

 hagen publishes some estimates of the velocities 

 of flight based on the latest principles of scientific 

 observation. As an expert on the use of anti- 

 aircraft appliances during the war he has been 

 able to bring exact science to bear on the question 

 in a manner that hitherto has been impossible. 

 The observations made near Montreuil in north- 

 east France were by means of theodolites on a 

 1,420 base with small balloons to ascertain the 



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