208 APPENDIX. 



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

 ments, the results of which may not be uninteresting ; for, 

 besides being of practical use in the cultivation of most 

 plants, they demonstrate also several facts of importance to 

 physiology. " The first experiment which naturally sug- 

 gested itself, was to mix a certain proportion of charcoal with 

 the earth in which different plants grew, and to increase its 

 quantity according as the advantage of the method was per- 

 ceived. An addition off of charcoal, for example, to vegeta- 

 ble mould, appeared to answer excellently for the Gesneria, 

 and Gloxyma, and also for the tropical Aroidecs with tuberous 

 roots. The two first soon excited the attention of connois- 

 seurs, by the great beauty of all their parts and their general 

 appearance. They surpassed very quickly those cultivated 

 in the common way, both in the thickness of their stems and 

 dark colour of their leaves ; their blossoms were beautiful, 

 and their vegetation lasted much longer than usual, so much 

 so, that in the middle of November, when other plants of 

 the same kinds were dead, these were quite fresh and 

 partly in bloom. Aroideae took root very rapidly, and their 

 leaves surpassed much in size the leaves of those not so 

 treated ; the species, which are reared as ornamental plants 

 on account of the beautiful colouring of their leaves, (I mean, 

 such as the Caladium bicolor, Pictum, Pcecile, &.C.), were 

 particularly remarked for the liveliness of their tints; and it 

 happened here also, that the period of their vegetation was 

 unusually long. A cactus planted in a mixture of equal 

 parts of charcoal and earth throve progressively, and attained 

 double its former size in the space of a few weeks. The 

 use of the charcoal was very advantageous with several of the 

 Bromeliacea, and Liliacece, with the Citrus and Begonia also, 

 and even with the Palmce. The same advantage was found 

 in the case of almost all those plants for which sand is used, 

 in order to keep the earth porous, when charcoal was mixed 

 with the soil instead of sand ; the vegetation was always 

 rendered stronger and more vigorous. 



" At the same time that these experiments were performed 



