Royal Socielij. 553 



being in full north declination, and proceeding through her remain- 

 ing positions to the time when &he crosses the equator to resume the 

 northern declination ; at which season, the whole pressure that had 

 been withdrawn from the atmosphei'e is suddenly restored. The 

 author thinks there is evidence of a great tidal wave, or swell in the 

 atmosphere, caused by the moon's attraction, preceding her in her 

 approach to, and following her slowlj' as she recedes from these la- 

 titudes ; so that were the atmosphere a calm fluid ocean of air, of 

 uniform temperature, this tide would be manifested with as great re- 

 gularity as those of the ocean of waters. But the currents uniformly 

 kept up by the sun's varying influence eif'ectually prevent this from 

 taking place, and involve the problem in complexity. He finds that 

 there is also manifested in the lunar influence a gradation of effect, 

 which operates through a cycle of eighteen years. The mean press- 

 ure of the atmosphere during the first part of this period increases ; 

 and then, after preserving for a year its maximum amount, again 

 decreases through the remaining years of the cycle, but exhibits, 

 towards its minimum, some fluctuations before it again regularly 

 increases*. 



2. " On a remarkable depression of the Barometer in November 

 1840, agreeing very closeh^ in its movements and results with that 

 of December 1821." By Luke Howard, Esq., F.R.S. 



The object of the author in the present paper is to show the close 

 correspondence of the extraordinary depression of the barometer in 

 the months of October and November of last year (1840), and of 

 the remarkably stormy weather which prevailed at the same period, 

 with similar phtenomena occurring in December 1821, when the 

 moon's place in declination underwent the same changes during 

 those two periods, at an interval of nineteen years. 



3. " General results of Meteorological Observations at Constanti- 

 nople." By J. W. Redhouse, Esq. Communicated by John Davy, 

 M.D., F.R.S. 



4. "Term- Observations made at Prague in November and De- 

 cember 1840, and January 1841." By C. Kreil. Communicated 

 by S. Hunter Christie, Esq., M.A., Sec. R.S. 



March 18. — The following Magnetical and Meteorological Obser- 

 vations, taken in conformity with the Report drawn up ])y the Com- 

 mittee of Physics including Meteorology, for the guidance of the 

 Antarctic Expedition, as also for the various fixed Magnetic Obser- 

 vatories, have been communicated by the Lords Commissioners of 

 the Admiralty, and by the Master- General of the Ordnance, viz. — 



1. "Magnetic-term Observations, taken at Kerguelcn's Land, 

 for May and June 1 840." By Capt. James Clark Ross, R.N., F.R.S., 

 Commander of the Expedition. 



2. " Hourly Magnetic Observations taken at Kerguelen's Land, 

 commencing May 25, and ending June 27, 1840." By Capt. James 

 Clark Ross, R.N., F.R.S., &c. 



3. " Meteorological Observations taken on board Her Majesty's 

 Ship Erebus, for October, November, and December 1839, and from 



[• On tlic subject of tliis pajjcr sec p. 5.J.5 and 559.] 



