664 



SCIENCE. 



[N. S. Vol. XL No. 278. 



the sum of $5000 to be a part of a contribution 

 to a building fund to erect a building for the 

 use of the Washington Academy of Sciences and 

 the local or affiliated societies, on condition that 

 the land needed for such a building be given by 

 the Government or obtained from other sources, 

 and furthermore, that the sum of §100,000 at 

 least be raised for that purpose, and that the 

 National Academy of Sciences have such priv- 

 ileges granted^as they may need. 



Mr. Agassiz also offered to give $1000 tov^^ards 

 a general fund for the National Academy of 

 Sciences, provided that $20,000 be raised for 

 that purpose. Mr. Theo. Gill offered to donate 

 $500 to the general fund. These offers were 

 accepted by the Academy, and committees will 

 in due time be appointed to obtain subscriptions 

 to these funds. 



The following papei-s were read in the scien- 

 tific session : 



I. ' The Anatomy of Nautilus pompilius ': L. E. 

 Geiffin. (Introduced by W. K. Brooks.) 



II. ' West Indian Madreporarian Polyps ' : J. E. 

 Ddeeden. (Introduced by W. K. Brooks. ) 



III. ' On the Use of Electric Motors, of the Shunt 

 Type, for Solving Linear Differential Equations of 

 any Order with Variable CoefBoients ' : Reginald A. 

 Fessenden. (Introduced by Cleveland Abbe. ) 



IV. 'On the Prediction of the Physical Properties of 

 the Pure Metals ' : Reginald A. Fessenden. (In- 

 troduced by Cleveland Abbe. ) 



V. ' A Partial Explanation of some of the Princi- 

 pal Ocean Tides': Eollin A. Harris. (By per- 

 mission of H. S. Pritchett. Introduced by Cleve- 

 land Abbe.) 



VI. ' Secondary Enrichment of Sulphides in Ore 

 Deposits ' : S. F. Emmons. 



VII. ' The Cruise of the U. S. Fish Commission 

 Steamer Albatross in South Seas, August, 1899, to 

 March, 1900 ' : A. Agassiz. 



VIII. ' Oa the Zoogeographical Relationships of 

 Africa ' : Theodore Gill. 



IX. ' Report of the Watson Trustees on the Award 

 of the Watson Medal to David Gill' : Simon Newcomb. 



X. ' A Human Bone from the Glacial Deposit at 

 Trenton, N. J.': F. W. Putnam. 



NEW YORK ACADEMY OF SCIENCES. 



SECTION OF ASTEONOMY, PHYSICS AND 



CHEMISTRY. 



A MEETING of the Section was held on Mon- 

 day evening, April 2nd. Professor William 



Hallock, of Columbia University, discussed the 

 overtones of a tuning fork. The first regular 

 overtone of a tuning fork is about two and a 

 half octaves above the fundamental, but Lord 

 Rayleigh pointed out that when the amplitude 

 of the vibration became so great that the restor- 

 ing force was no longer proportional to the dis- 

 placement, the octave appeared, as indicated 

 by theory. Lord Rayleigh recognized the 

 presence of the octave with his ear, and by the 

 use of a resonator. Professor Hallock obtained 

 direct evidence of this effect by means of a 

 photograph of a manometric flame, the capsule 

 of which was resting against the prong of the 

 fork. 



In a paper on 'Specific Gravity Weighings,' 

 Professor Hallock spoke of a number of points 

 in which the ordinary operations can be im- 

 proved. It is very convenient to use the prin- 

 ciple of the Jolly balance, in which there is a 

 pan always immersed, to hold the body when 

 weighing it in water. The effect of capillarity 

 on the supporting wire, which at best lessens 

 the sensibility of the balance, can be avoided 

 by sending a series of little waves across th& 

 surface of the water while weighing. To get 

 rid of bubbles in little corners of irregular 

 bodies, these bodies may be held under the tap 

 at the sink and moistened with water before 

 immersion, or still better, they may be moist- 

 ened with alcohol and then with water before 

 immersion. 



Professor M. I. Pupin of Columbia Univer- 

 sity, described a new faradmeter which he had 

 devised, an instrument for measuring the ca- 

 pacity of a condenser. This instrument is es- 

 sentially a Wheatstone's bridge using alternat- 

 ing currents, in which one leg of the bridge 

 consists of two resistances in series, and the 

 other leg consists of two capacities in series, 

 one of the two being that of a standard con- 

 denser, the other being the unknown capacity 

 to be measured. In the bridge connecting the 

 two points, one between the two resistances, 

 the other between the two capacities, is a tele- 

 phone. If the two separate circuits each con- 

 taining one of the two capacities, are arranged 

 so that the capacity reactance is by far the 

 greatest part of the impedance in that circuit, 

 then silence in the telephone will be obtained 



