364 TRANSACTIONS OF SECTION A. 



The following business was then transacted : — 

 1. Discussion on Gravitation. Opened bij E. Cunningham. 



2. Report on the DetenninaLion of Gravity at Sea. 

 See Appendix p. 549. 



3. Efficiency of Siumpots in relation to Terrestrial Magnetic 

 Phenomena.^ By Eev. A. L. Cortie, S.J. 



4. Report of the Seisniological Committee. — See Eeports, p. 20. 



5. The Mean Distances of Stars of different Magnitudes. 

 By Sir F. W. Dyson, F.R.S. 



THURSDAY, SEPT EM BE li 7. 



The following bueiness was transacted : — 



1. Discussion on Osmotic Pressure. Opened Inj Professor 

 A. W. Porter, F.R.S. 



2. The Measurement of Time. By Professor H. li. Turner, F.R.S.^ 



3. lonisation Potential. By Professor J. C. McLennan. 



F HI DAY, SEPTEMBER 8. 



The following Papers were received : — 

 1. X-Ray Spectra of the Eleme7lts.^'- By Sir E. Rutherford, F.R.S. 



2. Propagation of a Signal in a Dispersive Medium. 

 By Professor T. H. Havelock, F.R.S. 



Department of General Physics. 



3. Can the Frequencies of Spectral Lines he represented as a Function 

 of their Order?' By Professor W. H. Hicks, F.R.S. 



' See Monthly Notices, li.A.S., vol. Ixxvi., pp. 15-16, 631-634. Ibid., 

 vol. Ixxiii., pp. 539-543. 



- Published in Monthly A''otices, R.A.S., vol. Ixxvii., No. 1. 



' Published in The Observatory, vol. xxxix., p. 419-425. 



* See Engineering, October 6, 1916, p. 320. 



° See the A^tropliysical Journal, November 1916, vol. xliv., p. 229. 



