118 



Presents. 



[Dec. 9, 



Chase (P. E.) Some Remarks on the Fall of Rain, as affected by the Moon. 



On some General Connotations of Magnetism. 8to. Philadelphia 



1868. The Author. 



Hugueny (F.) Le Coup de Foudre de Tile du Rhin pres de Strasbourg 



(13 Juillet, 1869). 4to. Strasbourg 1869. The Author. 



Lea (Isaac) Descriptions of Twelve New Species of Unionidce from South 



America. Notes on some Members of the Feldspar Family &c. 8vo. 



Philadelphia 1868. The Author. 



Rees (G. Owen, F.R.S.) The Harveian Oration delivered at the Royal 



College of* Physicians, June 26, 1869. 12mo. London 1869. 



The Author. 



Smiles (R.) Memoir of the late Henry Booth, of the Liverpool and Man- 

 chester, and afterwards of the London and North- Western Railway. 

 8vo. London 1869. Miss Booth. 



Tuson (R. V.) A Pharmacopoeia, including the Outlines of Materia Medica 

 and Therapeutics, for the use of Practitioners and Students of Veteri- 

 nary Medicine. 12mo. London 1869. The Author. 



The following communications were read : — 



I. " Spectroscopic Observations of the Sun." — No. V. By J. Nor- 



man Lockyer, F.R.S. Received July 8, 1869. (See p. 74.) 



II. " Researches on Gaseous Spectra in relation to the Physical Con- 



stitution of the Sun, Stars,, and Nebulae." — Third Note. By E. 

 Frankland, F.R.S., and J. Norman Lockyer, F.R.£. Re- 

 ceived July 14, 1869. (See p. 79.) 



III. " On the successive Action of Sodium and Iodide of Ethyl on 

 Acetic Ether." By J. Alfred Wanklyn, F.C.S. &c. Com- 

 municated by Professor Williamson. Received July 16, 1869. 

 (See p. 91.) 



IV. " On Linear Differential Equations." By W, H. L. Russell, 



F.R.S. Received November 13, 1869. 



The condition that the linear differential equation 



(a+fix+ya?) £ + (a' + /3'a;+ y'x*) ^+(a"+/3"*+yV)«=0 

 ax ax 



admits of an integral ?* = e/ ?<ir , where (p is a rational function of (#), is 



given by the system of equations 



0 .. 



. Pr-1 



Qr-1 



R r _i S r _i 



0 



0 .. 



. 0 



0 . . 



. 0 





Qr Rr 



s r 



0 .. 



. 0 



0 . . 



. 0 



0 



Pr+1 Qr+1 



Pr+l 



S r +1 



.. 0 



Qr, 



R r , S r 



are given 



as follows. 









