43a 



they will surprise you, as being (so far as they go) entirely opposed 

 to Kupffer's opinion, that the superficial temperature of the earth 

 within the tropics is below that of the air, and to Boussingault's as- 

 sertion, as to the invariability of the temperature one foot below the 

 surface. The soil in which the thermometers are buried, is one 

 which very soon becomes compact again, after having been disturbed, 

 so that I do not think the rain can much affect the thermometers 

 noiv * * * * . The situation is on the top of the Observa- 

 tory hill ; the soil, the stone called Laterite." 



A subsequent letter contains the readings for four entire months, 

 and confirms the important conclusions mentioned above. The 

 mean annual temperature of the air at Trevandrum is 79°.24 F. 



The surface of the ground was grass-grown, and the thermometer 

 stems quite exposed. 



3. Researches in Hydrodynamics. Second Memoir. On 

 Waves. By J. Scott Russell, Esq., M.A., F.R.S.Ed., 

 &c. 



The object proposed by the author of this paper, was to present, 

 in a complete form, the results of investigations into the phenome- 

 na of Waves, in which he had been engaged for several years. A 

 part of the experiments referred to in the paper, had been carried 

 on by Sir John Robison, conjointly with the author of this paper, 

 as a Committee of the British Association. The others were new, 

 and had been carried on by himself, for the purpose of completing 

 and giving that systematic form to our knowledge of the subject, 

 which was attempted in this paper. 



The author finds that there may exist in agitated water waves 



