ON THE NATURE OF HEAT. J^15 



the best alpine variety, that I had ever been able to obtain, Seeds sowed in 

 in pots of mould, in the beginning of August, the seeds of "6^*'* 

 the preceding year having been preserved to that period ; 

 and the plants these afforded were placed, in the end of 

 March, in beds to produce fruit. ,*'^ 



This experiment succeeded tolerably well ; but I was not ^he plarrt^ "' 

 quite satisfied with it; for though my plants produced an j^o ^arly, 

 abundant autumnal crop of fruit, they began to blossom 

 souiewhat earlier than I wished, and before they were per- 

 fectly well rooted in the soil. I therefore tried the experi- Seeds sowed 

 laent of sowing some seeds of the same variety early in the 

 spring in pots, which I placed in a hotbed of moderate 

 strength in the beginning of April, and the plants thus 

 raised were removed to the beds in which they were to re- 

 main in the open ground, as soon as they had acquired a 

 sufficient size. They began to blossom soon after Midsum- y^®^^^*^ ^'"*' 

 mer, and to ripen their fruit towards the end of July, afford- 

 inga mostabundant autumnal crop of very fine fruit; and even 

 80 late as the second week in December I have rarely seen a 

 more abundant profusion of blossoms and immature fruit 



than the beds presented. The powers of life in plants thus Should always 



. , , . , . 1 be treated as 



raised, being young and energetic, operate much naore ^n annual. 



powerfully than in the humours of older plants, or even 



in plants raised from seeds in the preceding year; and 



therefore I think the Alpine strawberry ought always to be 



treated as an annual plant. 



xr. 



On the Nature of Heat. By Marshall Hall, Esq, In a 

 Letter from the Author, 



To W. NICHOLSON, Esq. 

 SIR, 



JL HE nature of caloric has long been a subject of inquiry Nature of ca- 

 in chemical philosophy. The first conjecture on this m&t- jTuestionwl 

 ter, which deserves attention, is that of Lord Bacon; his Hypothesis of 

 opinion has, however, been in a great measure superseded Bacon. 



