TO CORRESPONDENTS. 



Mr, W. R. Grove's Communication on Aplanatic Telescopes, and Mr. D. D. 

 Heath's on the Dynamical Theory of Deep-sea Tides, will appear in our next 

 Number. 



CORRELATION AND CONTINUITY. 

 Now ready, in 1 vol. 8vo, price 10s. 6d. cloth, 

 THE CORRELATION OF PHYSICAL FORCES. 

 By W. R. Grove, Q.C., F.R.S. 



A New Edition, being the Fifth, followed by a DISCOURSE ON CONTI- 

 NUITY, delivered by the Author as President of the British Association at Not- 

 tingham, 1866. This DISCOURSE may be had separately, price 2s. 6c?. 



London : Longmans, Green, and Co., Paternoster Row. 



Vol. I. with 13 Maps, price 8s., Vol. II. price 4s. 6d,, 



THE ELEMENTS: 



An investigation of the Forces which determine the Position and Movement? of 



the Ocean and Atmosphere. 



By William Leighton Jordan. 



To be completed in One more Volume. 



London : Longmans, Green, and Co., Paternoster Row. 



New Edition now ready, in 8vo, price 5s., 



AN ESSAY ON DEW, 



And several Appearances connected with it. 

 By W. C. Wells. 



Edited, with Annotations, by L. P. Casella, F.R.A.S., and an Appendix by 

 R. Strachan, F.M.S. 

 London : Longmans, Green, and Co., Paternoster Row. 



UNIVERSITY OF LONDON. 



In a few days, price 4s., 

 THE CALENDAR FOR THE YEAR 1867; 



Containing the Regulations for each Examination, the Examination Papers 

 set during the past year, and other information. 



Taylor and Francis, Printers and Publishers to the University, 

 Red Lion Court, Fleet Street. 



UNIVERSITY COLLEGE, LONDON. 



PROFESSOR WILLIAMSON'S COURSE OF LECTURES on ORGANIC 

 CHEMISTRY will commence on Monday, February 11. The Course will occupy 

 about Six Weeks, the Class meeting every day of the week except Saturday, from 

 11 to 12 a.m. Fee ,£2 2s. 



Charles Cassal, Dean of the Faculty of Arts. 

 Charles C. Atkinson, Secretary to the Council. 

 January 28, 1867. 



