Proceedings. 139 



invariants of a conic from the differential equation 

 discovered by Monge, and called by Halphen the differ- 

 ential invariant of a conic. Considerable simplification 

 results from taking as variables, magnitudes of which the 

 connection with the curve is of an intrinsic nature. 



Ordinary Meeting, February 9th, 1892. 



Edward Schunck, Ph.D., F.R S., F.C.S., President, in 

 the Chair. 



The thanks of the members were voted to the donors 

 of the books upon the table. 



By the nomination of the President, Mr. C. S. Trapp 

 and Mr. CHARLES O'Neill were appointed auditors of 

 the accounts for the current year. 



The President drew attention to a copy of the 

 " History of the Siege of Gibraltar," presented to the 

 Society by the author, Colonel Drinkwater, who served 

 with the Manchester Regiment during the famous siege, 

 and who was elected a member of the Society in the same 

 year in which the work was published and presented, 1786; 

 and also to a work on the " Department of Comptrollers 

 of Army Accounts " from the same pen, presented by 

 Colonel Drinkwater to the Society just fifty years later, 

 and containing an autograph inscription by him. A con- 

 versation on the Manchester Regiment and its officers 

 of the period of the siege ensued. 



Professor Osborne Reynolds described the principle 

 of Mr. Edison's proposed system of telephoning over great 

 distances at sea by means of condensers. 



