exxviii Journal of the Asiatic Society of Bengal. [N.S., XIV, 
shifts for certain lines are readily ik nee he on the hypothesis of a general 
recessive motion of the solar gases ; but t is implies an Earth effect. 
lines in the spectrum of Venus tip lanet is peers light from the 
hidden face of the Sun; and it is ho oped aes to secure data which 
will show which of the two hiypothease is false 
Improved formulae and sepa for Fabry and Perot's | 
interferometer.—By 
he formulae previously published involve the determination of the 
quantities, the focal length of the objective used to focus the interference 
rings on the slit of the auxiliary spectograph, and the magnification of the 
spectograph, in addition to measuri ng the diameters of the Bee Bys 
simple transformation, however, these two © quantities can be eliminated. 
A fo =e suitable for the measurement of small changes a wave 
length is give 
simple “aiathe d of adjusting the interferometer is suggested but its 
sensitiveness has not yet been thoroughly tested. 
On the use of Ritz’s method for finding the vibration | 
frequencies of oo strings and membranes— — 
Ce N. K. Masump 
The t of the writer is to show how grit Ber eager 
vibration reguencis of Masiecigenupus ee mbranes can be a 
wate the of a he germs hie are foams in 
Ss lica 
problems by man i la aba inoliidi Ritz himself, who 
the vibreiiog of sti rof. A. E. H. Love, who studied the theory 
— Prof. Kalahne nit Dr. Reinstein. 
On the use and effect of sealing-wax in the scandal 
the window of a vacuum tube, in which cathode rays 8 
produced by a gg of high tension electric dischang* 
—By 8. 8. Nune 
note Summarises th ed in the construction, 
the a coallad window ” or he express gua th as 
= photographs method for the determination of er ms 
ED sect expelled from radio-active product 
The range of a particles is one of the most important ¢ 
constants of the radio-active products from which they 4f@ ©*™ 
