November 24, 1893.] 



SCIENCE. 



2gi 



gain will enable the loird to turn and mount to a much 

 higher plane than it formerly occupied. On the face of 

 it I think this must strike every reader as extremely im- 

 probable and almost nonsensical. The opinion is strength- 

 ened as we continue on in the original discussion. Sup- 

 pose a bird to be soaring at a speed of twenty miles per 

 hour in a current which is itself moving at the same rate. 

 It is very evident that this velocity must have been at- 

 tained by the bird with almost no assistance from the air 

 current, for the resistance of the air against the soaring 

 bird it practically nothing. It is also evident that, if the 

 bird continues soaring in this current, it must lose the 

 velocity it had attained, and very quickly fall if not as- 

 sisted in some way. If it descends in an inclined plane, 

 its velocity, so far as the current of air goes, will not be 

 changed in the least, for two reasons. Fii'st, it has the 

 same velocity as the air current at starting on its down- 

 ward path, and hence the air current could not accel- 

 erate it any more than if it had continued soaring in a 

 horizontal plane. Second, as just suggested, the resist- 

 ance of the air is practically nothing, so that the current 

 will have no effect. The assumption that there is some 

 occult assistance given to the bird, because it is going- 

 down an inclined plane instead of horizontally, will not 

 be regarded as of any value by any one at all familiar 

 with the simplest principles of mechanics. 



But this is not all: an attempt is made to prove this 

 occult assistance from a concrete example. The author 

 takes a ship moving at twenty miles per hour and places 

 upon it an inclined plane, whose vertical height is 13.38 

 feet, which is the distance through which an object must 

 fall to attain a velocity of twenty miles per hour. Now, 

 if a ball should be allowed to roll down this inclined 

 plane, it would attain, so it is assumed, a velocity of 

 forty miles per hour with respect to the water outside of 

 the ship neglecting friction on the plane. This velocity 

 of forty miles per hour is made up, as the author states, 

 of the twenty miles per hour due to the motion of the 

 ship or the initial velocity, and twenty miles per hour ad- 

 ditional due to the acceleration from the fall of 13.38 

 feet in the descent of the ball on the inclined plane. 

 It is i^erfectly plain that there is no occult effect coming 

 in so far from the motion of the ship. The author shows 

 that with a velocity of forty miles per hour, if the ball 

 should roll upon an inclined jslane lixed off the ship, it 

 would rise to a point more than twenty-six feet higher 

 than the starting point. This conclusion is quite startling, 

 and shows a most serious fallacy in the reasoning. If the 

 ball had rolled up an inclined j)lane fixed to the ship, it 

 would have risen to exactly the same height as at starting, 

 as was clearly shown by Prof. J. P. Church. That the 

 ball would not rise to any such height will be clearly seen 

 by considering what would happen if it rolled from its first 

 position upon an inclined plane fixed upon the water. In 

 this case it would rise exactly 13.38 feet, and its motion 

 would cease altogether. 



The vicious reasoning is brought out very clearly even 

 in the original paper, for the author considers what 

 would happen if the ball fell vertically instead of rolling 

 down the inclined plane. In this case the twenty miles 

 per hour initial velocity he considers as equivalent to a 

 fall of 13.38 feet, and as the inclined plane is 13.38 feet 

 high, the total fall would be equivalent to 26.76 feet, and 

 he shows that with this fall the velocity attained would 

 be 28.28 miles per hour. That is to say, a ball rolling 

 down an inclined plane, where it must meet with a slight 

 resistance, will attain an accelerated velocity of twenty 

 miles per hour due to the fall of 13.38 feet; but, when the 

 same ball falls verticallj' in free air, and where it meets 

 with no resistance, its acceleration is only 8.28 miles per 

 hour. I am sure nothing farther is needed to show the 

 utter fallacy of all this reasoning. H. A. Hazen. 



Nov. 31, 



Portraits of Helmholtz. 



I THINK it will be of interest to the many admirers of 

 the distinguished physicist, Von Helmholtz, to know 

 that on his recent visit to this country he was induced 

 to sit for a photograph in the gallery of the well-known 

 artist, Mr. Brady, of Washington. 



Some most excellent pictures were obtained, copies 

 of which may be obtained by addressing Mr. M. B. 

 Brady, photographer, Washington, D. C. 



The prices are: For the largest size, 9x14, $2.00; 

 intermediate, 8x10, $1.00; cabinet, 25 cents. 



The cabinet size and the others {unmounted) will be 

 sent by mail. The larger sizes (mounted) must be sent 

 by express, at the expense of the purchaser — usually 

 25 to 35 cents. T. C. Mendenhall. 



Washington, D. C, Nov. 7. 



Songs of Birds. 



Had I not expected that we should have more satisfac- 

 tory answers to the query as to whether the voices of 

 birds expressed emotion or not, I should have ventured a 

 word before now. 



I think any student or observer of birds, who has care- 

 fully noted them with his heart in the study, will agree 

 with me when I say that if there is such a thing as ex- 

 pression of emotion in voice, then bird voices most clearly 

 express it. The mere fact that a bird soon forgot his loss 

 and grief, and sang in the natural bouyancy of his spirits, 

 or that another, lame and confined, was yet happy, and 

 expressed his happiness in his song, certainly does not 

 prove lack of emotional expression in the voices of birds. 



The untrained ear may fail to detect the difference in 

 the joyful and sorrowful notes of some birds, but surely 

 the ear must be indifferent, indeed, that does not detect 

 plain expression of sentiment or of joy in the happy song, 

 or of sorrow in the disturbed wail of any of the common 

 birds about our doors. 



The gift of voice was unquestionably intended as a 

 means of expression to all creatures thus endowed, and 

 wherever our powers of comprehension enable us to hear 

 and understand them aright, we cannot fail to detect 

 expression in them. 



This may seem a trivial matter to bring up at this time, 

 but it seems hardly fair that we should pass over the mat- 

 ter without giving to birds and all other creatures their 

 just dues. B. S. Bo.wdish. 



Phelps, N, Y., Nov. i, 1S93. 



Dictionary of Scientific Names. 



Through your query column, permit me to ask if there 

 has ever been j)tiblished a pronouncing dictionary of 

 scientific names in use in the studj^ of natural science for 

 the benefit of the young student who does not care to 

 delve too deeply into the study of Latin, and if not, why 

 would not such a publication be a welcome addition to our 

 library ? B. S. Bowdish. 



Phelps, N. Y., Nov. 9, 1893. 



Origin of the Carvings and Designs of the Alaskans and Vancouvre 

 Indians. 



A few years ago I crossed the ocean on a slow 

 steamer in company with a returning missionary, who 

 had spent fourteen years among the Vancouvre Indians. 

 He had with him a large collection of carved imple- 

 ments and/ac simile drawings of the quaint figures on 

 their boats and other objects. His opinion was that 

 they were Japanese in design; that at some time some 

 people from that country had been blown across the 

 Pacific, and left there traces of their arts, which were 

 perpetuated. He thought there -were some traditions 

 among the Indians that pointed that way also. 



In looking over the collections at the Exposition this 



