STUDY XI. 



I29 



which is, on the contrary, in a vertical plane, 

 opens at feven o'clock, and fhuts at ten. 



From a feries of fimilar obfervations it was, that 

 the celebrated Linnaus had formed a botanical 

 time-piece ; for he had found plants which opened 

 their flowers at every hour of the day, and of the 

 night. There is cultivated in the King's Garden, 

 at Paris, a fpecies of ferpentine aloes, without 

 prickles, whofe large and beautiful flower exhales 

 a ftrong odour of the vanilla, during the time of 

 it's expanfion, which is very fliort. It does not 

 blow till toward the month of July, and about 

 five o'clock in the evening: You then perceive it 

 gradually open it's petals, expand them, fade, 

 and die. By ten o'clock of the fame night, it is 

 totally withered, to the great aftonifhment of the 

 fpectators, who flock in crowds to the fight ; for 

 what is uncommon is alone admired. The flower 

 of our common thorn, I do not mean that of the 

 white-thorn, is ftill more extraordinary; for it 

 flowers fo rapidly, that there is fcarce time to ob- 

 ferve it's expanfion. 



Thefe obfervations, taken in their connection, 

 clearly demonftrate the relations of the corolke 

 to the heat of the Sun. To all thofe which have 

 gone before, I fliall fubjoin one more, by way of 

 conclufion, which evidently proves the ufe for 



vol.'iii. k which 



