416 



SCIENCE 



[N. S. Vol. LIV. No. 1400 



the lamented late Professor Struve. The observa- 

 tory at Potsdam was shown by Professor Luden- 

 dorff, who recently has been appointed director of 

 the Astrophysical Observatory. 



A visit was paid also to the Geodetic Institute. 

 At the wireless station the guests had the oppor- 

 tunity of listening to the wireless time signals from 

 Annapolis. 



One afternoon was devoted to an excursion on 

 the Havel to the Wannsee and Nikolskee. At a 

 tea in the library an opportunity was afforded for 

 viewing Professor Darmstadter 's collection of let- 

 ters of celebrated naturalists and autographs of 

 noted astronomers. 



A feature of the meeting was the gathering in 

 the large dome of the Potsdam Observatory, where 

 refreshments were served and a social evening 

 spent, the success of which was in a large measure 

 due to the ladies of the observatory staff and others. 



The four-days sessions are said to have passed 

 without a jarring note and aU parted with satisfac- 

 tion at the scientific results that had been brought 

 forth at the meeting and at the pleasure of having 

 again renewed old friendships together with grati- 

 tude for the hospitality extended to them at Pots- 

 dam. The next meeting is to be held at Copenhagen. 



AMERICAN MATHEMATICAL SOCIETY 



The twenty-eighth summer meeting of the Amer- 

 ican Mathematical Society was held at Wellesley 

 College, September 7-9, 1921, in conjunction with 

 the meeting of the Mathematical Association of 

 America. The attendance included ninety-one mem- 

 bers of the Society. Eleven new members were 

 elected, and thirty applications for membership 

 were received. 



Two joint sessions were held with the Mathe- 

 matical Association of America, at which papers 

 were read by Professor James Pierpont, on Some 

 mathematical aspects of the theory of relativity; 

 and by Professor A. C. Lunn, on The place of the 

 Einstein theory in theoretical physics. The follow- 

 ing papers were read at the regular sessions of the 

 Society : 



Einstein static fields which admit a continuous 

 group Gj of transformations into themselves : L. P. 



ElSENHART. 



On the class of a certain type of Einstein 

 spreads: John Eiesland. 



The solar gravitatioTial field and certain other 

 fields completely determined by light rays : Edwakd 

 Kasnee. 



Prime-power groups containing only one invariant 

 subgroup of every index which exceeds this prime 

 number: G. A. Miller. 



General mean value relations: G. D. BiEKHOrF. 



On plates of variable thickness: G. D. Birkhoff. 



Application of least squares to the problem of 

 apportionment: E. V. Huntington. 



The summation by series by means of generating 

 functions: I. J. Schwatt. 



The expansion of any power of a multinomial: 

 I. J. Schwatt. 



The operator (r(d/dr) ) onF{r) : I. J. Schwatt. 



Geometric characterization of special singly infi- 

 nite families of heat curves: Eugenie 0. Hausle. 



On the stability of a bicycle with a light frame: 

 J. L. Synge. 



Note on the definition of a linea/r functional: 



C. A. Fischer. 



Certain theorems concerning simple closed and 

 open curves: J. R. Kline. 



A theorem concerning connected sets which 6e- 

 come totally disconnected upon the removal of a 

 single point : J. R. Kline. 



Concerning connectedness im Meinen and a re- 

 lated problem: R. L. Moore. 



The probability function for the sum of certain 

 functions, with applications to the theory of errors: 



E. L. DODD. 



On power series with positive real part in the 

 unit circle: T. H. Gronwall. 



Some theorems on transformations with invariant 

 points: J. W. Alexander. 



Theorem on the interior of a simply connected 

 closed surface in three-space : J. W. Alexander. 



A fundamental class of geodesies on closed sur- 

 faces of genus greater than unity : H. M. Morse. 



On the problem of steering an automobile around 

 a corner : A. G. Webster. 



On the principles of mechanical integrators for 

 differential equations, especially those of exterior 

 ballistics: A. G. Webster. 



On the Fourier's series of non-integrable func- 

 tions: C. N. Moore. 



A generalisation of Laguerre's rule of signs: C. 



F. GUMMEE. 



The functions analogous to Lebesgue constants 

 for a series of Sermite polynomials: R. E. Gilman. 



Theory of invairiant elements: O. E. Glenn. 



On the location of the roots of the jacobian of 

 two binary forms: J. L. Walsh. 



The power of a modern gun and of thunder: J. 

 E. RowE. 



Spurious correlation applied to urn schemata: J. 

 E. Musselman. 



The significance of the partial correlation coeffi- 

 cient in the comparison of ordered statistical series 

 possessing rectilinear trends: W. L. Crum. 



A tentative substitute for the standard deviation 

 in the examination of the dispersion of an ordered 

 statistical series: W. L. Crum. 



The value of a sample. Second paper: B. H. 

 Camp. 



A form of series for potential problems: Noe- 

 bert Wiener. 



Some hydrodynamic aspects of group theory: S. 



D. Zeldin. 



Two-way series for Lebesgue integrals: M. B. 

 Porter. 



R. G. D. Richardson, 

 Secretary 



