ADDRESS BY PROFESSOR DAUBENV. XXVU 



traction of the air around, producing a series of aerial pulses. Dr. Hud- 

 son considers that their particular experiments appear more reconcileable 

 to his than to Prevost's theory, and, therefore, that the former deserves 

 to be further investigated. 



In compliance with a wish expressed by the Meteorological Commit- 

 tee, Dr. Apjohn has investigated the theory of the Wet-bulb Hygrometer, 

 and communicated an account of his experiments on this subject at the 

 Dublin Meeting. His paper, having been already published in the 

 Transactions of the Dublin Academy, does not appear in our Report, 

 which, however, contains two very interesting communications on sub- 

 jects of Meteorology. 



Mr. Snow Harris has presented a statement of the variations of the 

 thermometer at the Plymouth Dock-yard, as noted down by the war- 

 dens and officers of the watch, during every hour of the day and night, 

 commencing on the 1st of May, 1832, and terminating in December, 

 1834, which are also checked by a concurrent series of thermometrical 

 observations, registered every two hours, at the request of the Associa- 

 tion, by the late lamented Mr. Harvey. 



Thus have been afforded us, for two complete years, obsen'ations to 

 contrast with those taken during 1834 and 1835, at Leith Fort, under 

 the superintendence of the Royal Society of Edinburgh. 



Mr. Snow Harris has deduced from an average of these obser\'ation3 

 the following important results : — 



1st, The mean temperature of various seasons, as well as that of the 

 entire year. 



2ndly, The daily progression of temperature. 



Srdly, The two periods of each day at which the mean temperature 

 occurs. 



4thly, Tlie relation between the mean temperature of the whole twenty- 

 four hours, and that of any single hour. 



5thly, The average daily range for each month. 



6thly, The form of the cur\'es described by the march of the tempera- 

 ture between given periods of the day and night. 



In this manner has been accomplished one of the first undertakings 

 suggested by the British Association to its members, and promoted by 

 its funds, and the true form of the diurnal and annual curves in an im- 

 portant station of our southern coast been attained, as a standard of 

 comparison with that arrived at by Sir David Brewster in the latitude 

 of Edinburgh, and from which they exhibit in the results some extremely 

 curious and important discrepancies. 



Professor Phillips and, Mr. Gray have presented us with a continuation 



