198 Proceedings of the Royal Society of Edinburgh. 

 Monday, \st May 1843. 

 Sir T. M. BRISBANE, Bart., President, in the Chair. 

 The following Communications were read : — 



1. An attempt to explain the Phenomena of the Freezing 



Cavern at Orenburg. By Dr Hope.* 



2. Observations on the Temperature of the Earth in India. 



By John Caldecott, Esq. Communicated in a Letter to 

 Professor Forbes. 



These thermometers, made by Mr Adie of Edinburgh, were sunk 

 4n the ground at Trevandrum, in lat. 8° 30' W, to depths of 3, 6, 

 and 12 French feet. Mr Caldecott says, — " I send you herewith 

 the readings of my long thermometers, which, from various causes, 

 I was not able to put into the ground until the 1st of last May 

 (1842). These two months' readings, therefore, will not, of course, 

 have the proper temperature at the respective depths, especially as 

 it has been raining more or less nearly ever since. Still, I think 

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

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

 within the tropics is helow 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 

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

 tory hill ; the soU, 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. 



1842. 



May,... 

 June,... 

 July,... 

 Augustj 



12 Feet. 



84.672 



84.805 

 84.240 



6 Feet. 



85.157 

 84.562 

 83.627 

 82.800 



3 Feet. 



83.820 

 82.062 

 81.025 

 80.220 



Air. 



80.09 

 79.32 



78.73 

 77.90 



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. 



* Already published in this Journal, vol. xxxv. p. 191. 



