Published by Clay and Sons, Ave Maria Lane. 
CATALOGUE OF SCIENTIFIC PAPERS, 
COMPILED BY THE ROYAL SOCIETY. 
Vol. II (1874-83). Pet—Zyb. Price 25s., cloth. 32s., half-morocco. 
TLe back yolumes on sale as follows :—Vols. 1-6 (1800-63), cloth (vol. 1 in half morocco) £4 net; half- 
morocco, £5 5s. net. Yols. 7, 8 (1864—73), cloth, £1 11s. 6d. net; half morocco, £2 5s. net. Single vols., 
cloth, 20s.; half morocco, 28s. net. Yols. 9, 10 (1874-83), cloth £1 5s. net; half-morocco, £1 12s. net. 
A reduction of price to Fellows of the Royal Society, 
Published by Kegan Paul, Trench, Trubner, and Co. 
Royal 4to, pp. xiv.—326, cloth. Price 21s. 
OBSERVATIONS OF THE INTERNATIONAL POLAR EXPEDITIONS. 
1882-1883. 
FORT RAE. 
With 32 Lithographic Folding Plates. 
A reduction of price to Fellows of the Royal Society. 
Published by Kegan Paul, Trench, Trubner, and Co. 
A few copies at the reduced price of £1 Is. (published at £3). 
Royal 4to, pp. i v.—936,cloth. 
A MONOGRAPH OF THE HORNY SPONGES. 
By R. VON LEKDENFELD. 
With 51 Lithographic and Photographic Plates. 
A further reduction of price to Fellows of the Royal Society. 
Published by Kegan Paul, Trench, Trubner, and Co. 
In 1 v'ol., 4to. Pp. 500. With 6 Chromolithographs of the remarkable Sunsets of 1883 and 
40 Maps and Diagrams. 
THE ERUPTION OF KRAKATOA AND SUBSEQUENT PHENOMENA. 
Report of the Krakatoa Committee of the Royal Society. 
Edited by G. J. SYMONS, F.R.S, 
Price 30s. To Fellows, 20s. 
