December 16, 1921] 



SCIENCE 



605 



Nowhere do we regard the fork as made up 

 of two bars attached to a solid base. Since 

 the question of how we may best regard a 

 vibrating tuning fork has been raised, we 

 have turned once more to Eayleigh.^ After 

 a mathematical discussion he writes: 



. . . These laws find an important application in 

 the case of tuning forks, whose prongs vibrate as 

 rods, fixed at the ends where they join the stalk, 

 and free at the other ends. 



Also Edwin H. Barton,* a pupil of Lord Eay- 

 leigh, writes; 



The behavior of the TJ-shaped bars just dealt 

 with approximates to that of tuning forks. But 

 the vibration of tuning forks is usually further 

 complicated by the presence of an additional block 

 at the center of the bend and the stem attached 

 thereto. Indeed, it may be a nearer approximation 

 to regard each prong as a straight bar fixed at the 

 end near the stem and free at the other end. 

 It appears, then, that this " crude " manner 

 of considering a tuning fork, which has been 

 wrongly attributed to us, is actually accepted 

 by no less an authority than Rayleigh and 

 his pupil. Barton. 



Profesor Wead's interpretation of our view 

 is probably based upon our statement that 

 the fork has a single node at the base. This, 

 of course, is only an approximation. 



An alternative explanation, according to 

 Professor F. E. Watson, of this university, is 

 to consider the fork as a single vibrating 

 system in which the center of mass tends to 

 remain fixed in position. As the tines of the 

 fork are bending outward, the center of mass 

 tends to lower, so that the stem and block 

 of the fork rise a bit so as to keep the posi- 

 tion of the center of mass unchanged. As 

 the tines return inward, the center of mass 

 tends to rise, so that the stem of the fork 

 lowers. The stem of the fork thus executes 

 minute up and down movements. 



Paul Thomas Young 



Untversity of Illinois 



an anecdote concerning dr. field 

 I HAVE read with great interest Dr. Ward's 

 sketch of the life and work of the late Herb- 



3 ' ' Theory of Sound, ' ' 1894, Vol. I., 274. 



4 " A Text-Book on Sound, ' ' 1908, 298. 



ert Haviland Field. It, however, omits any 

 mention of his appreciation of humor, and 

 perhaps I may be allowed to tell of one of 

 his practical jokes which, to me at least, was 

 most amusing. 



The late Henry B. Pollard had just com- 

 pleted his work on the anatomy of Polyp- 

 terus and had gone from Wiedersheim's 

 laboratory for lunch. I came in a little later, 

 started my studies, and then Pollard came 

 in, and in a moment I realized what " Uncle 

 Toby " meant when he referred to the pro- 

 fanity of " our army in Flanders." Pollard 

 turned to me, holding up a drawing of the 

 cranial nerves of that fish which was almost 

 completely cov)ered with hasmatoxylin, and 

 demanded who did it. I knew nothing of it 

 and so replied. Pollard said he would call 

 the attention of the professor (Wiedersheim) 

 to it and at once left the room. As he went 

 out of one door of the laboratory, the door 

 from the anatomical museum opened and in 

 came Field, who removed the damaged draw- 

 ing from Pollard's table, opened a drawer 

 and took out another drawing, and again 

 left the room. Pollard almost immediately 

 returned, bringing the professor with him. 

 " Look at that ! " said Pollard. " Was ist 

 los ? " asked Wiedersheim, and then Pollard 

 looked and saw his drawing in perfect con- 

 dition. I never saw such an expression of 

 complete inability to comprehend as that on 

 Pollard's face. He was utterly without words, 

 The explanation of the whole was that Field 

 had found the tracing paper which Pollard 

 had used, had rapidly redrawn on another 

 sheet the nerves and skull of Polypterus, had 

 deluged it with staining fluid and left it for 

 Pollard to find, waiting in the museum to 

 hear what the English youtli would and 

 could say. 



S. 



TWO RETROSPECTIVE FEATURES OF THE 

 TORONTO MEETING 



The membership list in the last volume of 

 the Summarized Procei^dings, recently pub- 

 lished, shows that the Association has a con- 

 siderable number of members living in coun- 



