APPENDIX TO PART I. 



EXPEKIMENTS AND OBSERVATIONS ON THE ACTION OF CHARCOAL 

 FROM WOOD ON VEGETATION. 



BY EDWARD LUCAS.* 



** In a division of a low hothouse in the botanical garden 

 at Munich, a bed was set apart for young tropical plants, 

 but instead of being filled with tan, as is usually the case, 

 it was filled with the powder of charcoal, (a material which 

 could be easily procured,) the large pieces of charcoal 

 having been previously separated by means of a sieve. 

 The heat was conducted by means of a tube of white iron 

 into a hollow space in this bed, and distributed a gentle 

 warmth, such as tan communicates, when in a state of fer- 

 mentation. The plants placed in this bed of charcoal quick- 

 ly vegetated, and acquired a healthy appearance. Now, as 

 always is the case in such beds, the roots of many of the 

 plants penetrated through the holes in the bottom of the 

 pots, and then spread themselves out ; but these plants 

 evidently surpassed in vigor and general luxuriance plants 

 grown in the common way, — for example, in tan. Several 

 of them, of which I shall only specify the beautiful Thun- 

 bergia alata, and the genus PeireskicR^ throve quite aston- 

 ishingly ; the blossoms of the former were so rich, that all 

 who saw it affirmed, they had never before seen such a 

 specimen. It produced also a number of seeds without 

 any artificial aid, while in most cases it is necessary to ap- 

 ply the pollen by the hand. The Peireskice grew so vigor- 

 ously, that the P. aculeata produced shoots several ells in 

 length, and the P. grandifolia acquired leaves of a foot in 

 length. These facts, as well as the quick germination of 

 the seeds which had been scattered spontaneously, and the 

 abundant appearance of young Filices, naturally attracted 

 my attention, and I was gradually led to a series of ex- 

 periments, the results of which may not be uninteresting ; 



* See page 78. 



