96 VITAL ACTIONS. 



low would not distribute the temperature in the same 

 way." 



These observations seem to confirm the late Mr. 

 Harvey's suspicions, that the real force of the sun's 

 rays in tropical countries is still far from being ascer- 

 tained. When, therefore, we are informed by tra- 

 vellers that the temperature in the sun, at Gondar, 

 has been seen to be 113° (Bruce) ; at Benares, 110°, 

 113°, 118° (Harvey) ; or at Sierra Leone, 138° (Win- 

 terbottom); it must be supposed that, in reality, the 

 temperature would have been found much higher in 

 those places, had more efficient means of observation 

 been employed. Mr. Foggo, indeed, succeeded, by 

 means of a large thermometer, having the ball covered 

 with black wool, and fully exposed to the direct rays 

 of the sun, unsheltered from the wind, in obtaining, 

 at Edinburgh, on the 29th of July, at 3h. 10 P. M. t an 

 indication of 150°, and at 2h. P. M. of 140° ; while 

 another instrument, similarly prepared, and resting 

 in contact with herbage, was found to indicate only 

 119° and 110°; so that, as Mr. Foggo remarks, a differ- 

 ence of 30° was produced' in these cases solely from 

 the manner in which the instruments were exposed. 

 (Edinburgh Philosophical Journal, No. xxvii.) 



118. For horticultural purposes, a very extensive 

 series of observations requires to be made at a very 

 great number of different places, with a view to deter- 

 mine the connexion between the temperature of the 

 soil and the seasons of vegetation; for it does not 

 appear that any such have yet been recorded, except 

 in this country, where, from their fewness, they are 



