696 



SCIENCE 



[N. S. Vol. XXX. No. 776 



companying increased permeability after mem- 

 brane formation. 



6. That an increase of surface tension, 

 which must accompany a change of potential 

 at the surface, is quite general in naked 

 eggs after fertilization, as indicated by their 

 rounding up when previously they had been 

 irregular in outline. 



A logical explanation is afforded why such 

 a change as increased permeability should 

 cause development, namely — the removal of 

 some reaction product whose accumulation 

 has brought the cycle of reactions occurring 

 during the growth period to a standstill. This 

 does not exclude the possibility that in time 

 another change may take place which leads 

 to those disintegrative changes, especially em- 

 phasized by Loeb. 



E. Kewton Haevet 



Columbia Univebsity, 

 October 7, 1909 



SOCIETIES AND ACADEMIES 



THE PHILOSOPHICAL SOCIETY OP WASHINGTON 



The 668th meeting was held on October 9, 1909, 

 Acting President Wead presiding. The following 

 papers were read: 



Reversion of Power Series: C. E. Van Oesteand, 

 of the Carnegie Institution of Washington. 

 The equation which Professors Harkness and 

 Morley developed for the reversion of a power 

 series was extended so as to obtain a general 

 term for the reverse series similar to the one 

 obtained by Professor MoMahon. The complete 

 expansion for the first thirteen coefficients was 

 given, and some comment was made in regard to 

 the application of the reverse series to inverse 

 functions including solutions of polynomials of 

 the TC-th degree. 



The Vibration Galvanometer : Feank Wennee, of 



the Bureau of Standards. 



The vibration galvanometer is an instrument 

 for the detection or comparison of small alter- 

 nating currents and electromotive forces. It dif- 

 fers from other instruments for the same purpose 

 mainly in having the moving system tuned to the 

 frequency of the current or electromotive force to 

 be investigated. 



The general theory of the instrument was de- 

 veloped, and equations derived which show how 

 the amplitude of the vibration depends upon the 



various constants of the instrument and the con- 

 ditions under which it is used. An auxiliary set 

 of equations gives all the constants in terms of 

 quantities easily measured. This makes it pos- 

 sible, with but few simple measurements on any 

 particular instrument, to predict its behavior 

 under almost any set of conditions, or to cal- 

 culate the effect of any contemplated change in 

 the design. 



It has been observed that some instruments 

 resonate to two different frequencies. The cause 

 of this double period of the moving system was 

 explained. For those instruments which develop 

 a relatively large back electromotive force the 

 effect of putting a large inductance in the circuit 

 is shown and the advantage of using a step-up 

 transformer is pointed out. 



The experimental part of the work has to do 

 mainly with the verification of the more impor- 

 tant relations shown by the equations. The con- 

 stants of the different instruments used were 

 obtained, using the theory developed. Some of the 

 constants are also determined by an independent 

 method and thus serve as checks on the theory. 

 A method of tuning was given which is more 

 sensitive than the method generally used and 

 which is applicable in other cases where the vibra- 

 tion is forced. 



W. P. White, of the Carnegie Institution of 

 Washington, spoke informally on the zero shift 

 in moving-coil galvanometers, discussing briefiy 

 its cause and how it may be lessened. 



E. L. Faeis, 

 Secretary 



THE CHEMICAL SOCIETT OP WASHINGTON 



The 192d meeting of the Washington Section 

 of the American Chemical Society was held at the 

 Gteorge Washington University Lecture Hall on 

 October 14, 1909. President Walker presided, the 

 attendance being 94. Dr. H. W. Wiley gave a 

 report of the seventh International Congress of 

 Applied Chemistry, held in London in May and 

 June of this year, including a history of the 

 development of the society. He described the 

 entertainments furnished by the British members, 

 told of the more important papers presented at 

 the meeting and of the personnel in attendance, 

 and the part taken by some of the prominent 

 American chemists. Twenty-one new names were 

 added to the list of members and twelve names 

 removed. 



J. A. LeClebc, 



Secretanf 



