Septembeb 11, 1896.] 



SGIENGE. 



347 



of Buffalo, who has a large collection of 

 Crookes' tubes with accessory apparatus for 

 the exhibition of the Eontgen rays. 



On Friday afternoon the section made a 

 special excursion to Niagara Falls, and the 

 members were courteously received at the 

 large Power House, at the Carborundum 

 Factory and at other places of interest. 



During the seven working sessions of the 

 section twenty-nine papers were read in 

 full and two by title. 



Polarization and Internal Resistance of a Gal- 

 vanic Cell: By B. E. Moore. 

 The E. M. F. between each electrode of a 

 cell of the Leclanche type, without depolar- 

 izer, and an auxiliary carbon electrode was 

 determined during the polarization of the 

 cell and during its subsequent recovery. 



The Lead Storage Cell : By B. E. Moore. 



The author explained from Nerst's theory 

 the character of the curves of charge and 

 discharge of a lead storage cell. 



A Theory of Galvanic Polarization : By W. S. 



Franklin and L. B. Spinney. 



The authors pointed out the existence of 

 a term in the energy equation of the electro- 

 lytic cell depending upon an irreversible or 

 sweeping process at each electrode. Experi- 

 ments were described showing that the co- 

 efficients of these terms do not in general 

 vanish with the current. 



On the Counter Electromotive Force of the Elec- 

 tric Arc: By W. S. Franklin. 

 The author attempted the experimental 

 determination of the decay of E. M. F. be- 

 tween the carbons of the electric arc after 

 the circuit is broken. It was pointed out 

 by G. W. Patterson that the results were 

 entirely ambiguous. 



On the Element of Diffraction in FresneVs Ex- 

 periments with two Mirrors and ivith the Bi- 

 prism: By Ernest R. von Nardroff. 

 The author discussed in detail the color- 

 ing by diffraction of the central band ob- 



tained by Fresnel's mirrors and Fresnel's 

 bi -prism. 



Segmental Vibrations in Aluminum Violins : 



By Alfred Springer. 



Five years ago the author pointed out that 

 the acoustical properties of aluminum are 

 approximate to those of wood. Continued 

 experiments made with aluminum sound 

 boards have verified this earlier conclusion. 

 The author exhibited several aluminum 

 violins, together with a device, called a bass 

 bar, by means of which the quality of the 

 tone produced by the instrument can be 

 controlled. 



Preliminary Note on a proposed new Standard 

 of Light: By Clayton A. Sharp. 

 It is proposed to define a standard of 

 light as a flame of definite size produced by 

 a gas of definite composition burning in a 

 continuously renewed atmosphere of defi- 

 nite composition. Experiments have been 

 made with a mixture of equal parts of acet- 

 ylene and hydrogen burning in an atmos- 

 phere of pure oxygen. The mixture of 

 acetylene and hydrogen issues from a small 

 tube, surrounding which is a larger tube 

 supplying oxygen. The importance of using 

 dry gases was pointed out. 



A Photographic Study of the Rontgen Rays: 



By W. A. Rogers. 

 Note on the Duration of the X-Ray Discharg'e 



in Croohes^ Tubes: By Benjamin F. 



Thomas. 



It has been found that slow make and 

 break in the primary of an induction coil pro- 

 duces almost as strong effect on a Crookes' 

 tube as very rapid make and break. This 

 seems to indicate the long duration of activ- 

 ity of the tube at each discharge. The au- 

 thor has shown, however, that the duration 

 of the acting discharge is as short as -5V77 

 second and probably as short as gq^oQ sec- 

 ond. 



Preliminary Communication concerning the 

 Anomalous Dispersion of Quartz for Infra- 



