XVll 



XXIV. "The 'Hunting' of Alternating-Current Machines." By 

 Bertram Hopkinson. Communicated by Professor 

 Ewing, F.B.S. 



XXV. " The Theory of Symmetrical Optical Objectives." By S. D. 



Chalmers. Communicated by Professor Larmor, Sec. 

 R.S. 



XXY1. "The Differential Invariants of Space." By Professor A. \l. 

 Forsyth, F.R.S. 



The Society adjourned over the Long Vacation to Thursday, 

 November 19. 



