250 APPENDIX TO PART I. 



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 in- 

 crease its quantity according as the advantage of the meth- 

 od was perceived. An addition of | charcoal, for exam- 

 ple, to vegetable mould, appeared to answer excellently for 

 the Gesneria and Gloxinia^ and also for the tropical Aroidtce 

 with tuberous roots. The first two soon excited the atten- 

 tion of connoisseurs, by the great beauty of all their parts 

 and their general appearance. They surpassed very quick- 

 ly those cultivated in the common way, both in the thick- 

 ness of their stems and dark color of their leaves ; their 

 blossoms were beautiful, and their vegetation lasted much 

 longer than usual, so much so, that in the middle of Novem- 

 ber, when other plants of the same kinds were dead, these 

 were quite fresh and partly in bloom. Aroideoe 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 coloring 

 of their leaves, (I mean, such as the Caladium bicolor, 

 Piduniy 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 Bromeliacece 

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

 with the PalmcB. 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 

 with mixtures of charcoal with different soils, the charcoal 

 was also used free from any addition, and in this case the 

 best results were obtained. Cuts of plants from different 

 genera took root in it well and quickly ; I mention here 

 only the Euphorbia fastuosa 3.ndfulgens which took root in 

 ten days, Pandanus utilis in three months, P. amari/llifolius, 

 Chamcedorea elatior in four weeks. Piper nigrum, Begonia, 

 Ficus, Cecropia, Chiococca, Buddleya, Hakea, Phyllanihus, 

 Capparis, Laurus, Stifftia, Jacquinia Mimosa, Cactus, in 



