APPENDIX. 207 



(February 1819) measures 7-J- feet between the extremity 

 of the root and the top of the branches, and the stem at the 

 thickest part is 5|- inches in circumference." 



EXPERIMENTS AND OBSERVATIONS ON THE ACTION OF 

 CHARCOAL FROM WOOD ON VEGETATION. BY EDWARD 

 LUCAS. 



(See page 61.) 



" 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 hav- 

 ing 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, 

 sufficient to have caused tan to enter into a state of fermen- 

 tation. The plants placed in this bed of charcoal quickly 

 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 vigour 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 Peireskia, throve quite astonish- 

 ingly; 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 apply the pollen 

 by the hand. The Peireskia grew so vigorously, that the 

 P. aculeata produced shoots several ells in length, and the 

 P. grundifolia 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 9 naturally attracted my 



