86 HKAlT OF THE ARUAf. 



in the afternoon till eleven or twelve at night. Its great- 

 est degree was seven of Reaumur's scale above the heat 

 of the air, which at the time of his observation was about 

 fourteen or fifteen of that thermometer. Such is the ac- 

 count with which I have been favoured by Dr. Bostock 

 of Liverpool, from a letter of M. Senebier*, dated Nov. 

 28, 1796, to M. De la Rive. 1 have not hidierto been 

 successful in observing the phaenomenon in question, 

 which however is well worthy of attention, and may 

 probably not be confined to this species oiArum. 



* It is now published in his Physiolog-ie Vegetale.v. S. 314, 

 where nevertheless this ingenious philosopher has declared his 

 opinion to be rather against the existence of a spontaneous heat 

 in vegetables, and he explains even the above striking phaeriom- 

 won upon chemical principles, which seem to me very inadequate. 



