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THE POPULAR SCIENCE MONTHLY. 



increased worrying of horses by flies before 

 rain, and the rise of the gossamer before 

 fine weather, are abundantly confirmed by 

 observation. 



Habits of Birds. Many interesting no- 

 tices, local and general, respecting birds are 

 to be found in the Abstract of the Proceed- 

 ings of the Linnaean Society of New York 

 for the year ending March 1, 1893. Frank 

 M. Chapman, reporting at one of the meet- 

 ings on the summer bird life of New York 

 and vicinity, said that 127 species might be 

 classed as summer residents, of which 108 

 were land birds and 19 water birds ; 22 spe- 

 cies might be considered abundant, 47 com- 

 mon, 31 tolerably common, and 27 rare. 

 Dr. C. S. Allen contributed at another meet- 

 ing an account of a breeding-place of peli- 

 cans on an island of Florida, a hundred and 

 fifty feet long by fifty feet broad, and cov- 

 ered with a dense growth of mangroves. 

 The nests were in bushes, ten or fifteen feet 

 from the ground, were made of sticks, 

 straw, dry weeds, etc., and held from one to 

 four eggs. The young, on emerging from 

 the shell, are of a size corresponding with 

 that of the egg, and slate-colored, from tint 

 of skin, with apparently scattering hairs 

 (casings) protecting white down ; but in a 

 few hours they appear to have increased to 

 several times the bulk of the egg, and be- 

 come white as soon as the down is freed 

 from the protective covering ; in a few days 

 they are as large proportionately as birds 

 usually are when a week or two old. The 

 increase in size is due, in part, to the power 

 the birds have of taking air into the spaces 

 beneath the skin which is very loose and 

 capable of being immensely inflated. They 

 remained in the nest only a few days, and 

 thereafter rested on the surrounding bushes. 

 Mr. Chapman instanced a number of cases 

 of protective coloration, notably that of a 

 flock of parrots flying into a palm tree, 

 whereupon they became almost indistinguish- 

 able from their surroundings, although not 

 hidden to any extent by the foliage. He de- 

 scribed, as illustrating the fact of the bird's 

 consciousness of its protective coloration, 

 the habit the Cuban meadow lark has of 

 turning its back to the observer, and also 

 the instance related by Mr. W. H. Hudson, in 

 his Argentine Ornithology, of a wounded bit- 



tern which persisted in turning its breast 

 toward its captor, although he endeavored to 

 pass around behind it. The bird, with its 

 slender neck pointing straight upward, could 

 not be distinguished from a seed stalk, ex- 

 cept on close scrutiny. Mr. Chapman said 

 that Dr. John A. Wells, of Englewood, 

 N. J., had recently watched a woodcock on 

 her nest, and was fully convinced that she 

 was aware of her resemblance to the sur- 

 roundings, for she remained perfectly quiet 

 and allowed of a very near approach ; but 

 when a fall of snow came, and Dr. Wells 

 again visited the sitting bird now a very 

 conspicuous object she flew before he had 

 approached within gunshot. The most nota- 

 ble example of protective mimicry is the Eu- 

 ropean cuckoo, which, by reason of its strik- 

 ing resemblance to a hawk, is able to de- 

 posit its eggs in the nests of other birds, 

 while they chatter and scold at a respect- 

 ful distance. Together with many other no- 

 tices of this kind, the Abstract of Proceed- 

 ings contains a paper by Tappan Adney 

 giving a list of bird names, etc., of the 

 Milicete Indians of the St. John Valley, New 

 Brunswick. 



Measuring the Heights of Clouds. Four 

 methods of measuring cloud heights have 

 been used at Blue Hill Observatory, Massa- 

 chusetts : 1. The bases of the lowest clouds 

 frequently float below the summit of the hill 

 (one hundred and twenty-six metres above 

 the general surface of the surrounding land), 

 and the altitude of the base can be ascer- 

 tained by walking down the side of the hill. 

 2. Measurements of the angular altitude of 

 the light reflected from clouds floating over 

 adjacent cities can be used for determining 

 the height of the clouds. 3. The shadows 

 of detached clouds can be seen from Blue 

 Hill for many miles moving across the sur- 

 face of the country, and, by timing the move- 

 ments of the shadows between points whose 

 distance apart is known, the velocity of the 

 cloud can be ascertained. From the actual 

 velocity and the angular velocity of the cloud 

 its height can be determined. 4. Simulta- 

 neous angular measurements of the altitude 

 and direction of the same cloud-point have 

 been made at two stations eleven hundred 

 and seventy-eight metres apart. An attempt 

 has also been made to determine the height 



