OCTOBKR 20, 1905.] 



SCIENCE. 



499 



period, expressing it again as dry grass on the 

 basis of Plall's analysis, the amount required 

 would be 27,420 pounds per "acre or, expressed 

 as hay containing 1.5 per cent, water, 15.7 tons. 

 Again, using Ebermayer's determinations for 

 the depth of 70 centimeters (27.6 inches) and 

 120 days, the computed loss of carbonic acid 

 from the soil below this depth would be repre- 

 sented by that carried by 31,960 pounds of dry 

 grass or 17.3 tons of hay per acre. In speak- 

 ing of the first instance cited the author says : 

 " We may say, then, that, in this case, car- 

 bonic acid is escaping from the soil at the 

 rate of about 0.04 cubic foot per day per square 

 foot and therefore that this was the rate of 

 production of carbonic acid in the soil at this 

 place below the depth of six inches." The 

 amoiTnt of carbon thus carried out of the soil, 

 according to the assumption and calculation, . 

 would be greater than the amount we have 

 calculated above by whatever was produced in 

 the surface six inches. It is clear, however, 

 that no such losses of carbonic acid, resulting 

 from the decomposition of organic matter, 

 could be maintained year after year, as the 

 amount of organic matter in the root system 

 of a crop is not equal to that produced above 

 ground, at least usually, and the amounts pro- 

 duced above ground are only rarely equal to 

 the amounts computed ; indeed they are seldom 

 more than one third of those quantities. It 

 must be concluded, therefore, that the labo- 

 ratory observations and methods of computa- 

 tion give a rate of diffusion of carbonic acid 

 from the soil of a field much greater than 

 actually occurs as a seasonal average. It 

 should be noted that in getting these enormous 

 losses of carbonic acid from the soil we have 

 included only one third of the year, while 

 Ebermayer's observations show that the 

 amounts present in the soil at all seasons, in- 

 cluding even winter, are large. 



In view^ of the relations to which we have 

 called attention it is clear that the general- 

 izations cited require critical field trials to be 

 made, bringing them to suitable tests before 

 they should be accepted with full confidence. 



F. H. King. 



Madisox, Wis., 



September 16, 1905. 



THE QUESTION AS TO WHETHER FALCONS WHEN 



SOARING INTERLOCK THEIR PRIMARY WING 



FEATHERS. 



The observations of Mr. Trowbridge upon 

 the habit of hawks when soaring to overlap 

 their primaries (i. e., on the upper side of the 

 wing) have several times been commented 

 upon adversely. And a well-known ornitholo- 

 gist has objected that this behavior of feathers 

 has not been previously observed, in spite of 

 the voluminous field notes as to the habits of 

 hawks, and that no one has been able to con- 

 firm the observation of interlocking feathers. 

 Accordingly, I am led to jot down the follow- 

 ing notes in favor of Mr. Trowbridge's results, 

 — for my observations are at first hand and 

 were made, I believe, under quite favorable 

 conditions. 



It so happened that we were coming up the 

 narrow canal from Sakai to Matsue in the 

 face of a strong wind, so strong, indeed, that 

 our small steamer labored to make headway 

 against it. At one point we disturbed a kite, 

 Milvus melanotus — a very common bird, by 

 the way, along Japanese waterways — which 

 rose slowly in the face of the wind and after 

 making several circles followed the margin of 

 the canal, flying and soaring, almost opposite 

 the boat and making about equal headway. 

 It did not occur to me at the moment that 

 the opportunity was a favorable one for watch- 

 ing the wing feathers (for the bird was some- 

 times as near as a hundred feet), when my 

 eye was caught by the behavior of the pri- 

 maries. The hawk was flying low, about the 

 height of the eye, and when the wing passed 

 through the plane of the horizon I could see 

 as the wing flapped that several primaries 

 stood out sharply, finger-like, dorsal to the 

 plane of the descending wing. This was so 

 conspicuous, indeed, that it seemed difficult to 

 conclude that these feathers could fold under 

 one another when, in face of a strong wind, 

 the wings became passive in soaring. Never- 

 theless, the distance of the bird was so great 

 that I could not convince myself that the in- 

 terlocking actually took place; I was only 

 sure that the primaries were bowed, so that 

 in soaring this part of the wing must have 



