Use of Charcoal in Pot Culture. 219 



increased to the size of a large turnip. This could have been 

 effected only by adding coatings to the outside, and cutting away 

 the interior layers, so as to afford space for increasing the number 

 of cells : but, as I never could discover the insects in the act of 

 carrying out the material thus cut away, I can only conjecture 

 that they work it up for the structure of the additional cells, as 

 they proceed. By this contrivance the cells are always carefully 

 protected. It is certain that when the nest has attained the 

 usual size, the coatings are more close and compact than while 

 the nest is in progress. I lately examined a very large hornet's 

 nest, and found the cells enclosed by eight or ten layers of a 

 substance like paper. This the insect may be often seen col- 

 lecting from dry, unpainted wood ; its mouth being admirably 

 adapted to the purpose. — Cossey Hall Gardens, March 7. 1841. 



Art. VIII. Further Results of the Experiments on the Application 

 of Charcoal, as a Mixture "with Earth, for the Cultivation of Plants 

 in Pots. By M. Edward Lucas, Assistant Gardener in the 

 Royal Botanical Garden at Munich. 



(From the Garten Zeitung for 1840, p. 66.) 



According to my promise, I now lay before my readers the 

 experiments I have made in the application of charcoal to another 

 purpose, viz. using it as a mixture with various sorts of earth. 

 It showed here also the same extraordinary effect ; and all the 

 plants that have hitherto been subjected to this treatment have 

 been as much distinguished by their luxuriance of growth, as 

 by the more perfect developement of their individual parts. This 

 was particularly the case with tuberous-rooted plants, which, 

 besides their perfect developement, had also a much longer 

 period of vegetation ; so that the difference in this respect, between 

 those that were cultivated in their usual soil and those which 

 had a mixture of charcoal, amounted to nearly two months. I 

 was led to this by several trifling circumstances. 



A very suitable treatment introduced into this botanic garden 

 of plunging pots with bulbous or tuberous rooted plants taken 

 up every year, for a few weeks after potting, or till they begin 

 to shoot, in a moderate hotbed, covering them an inch deep with 

 earth, was applied the previous year. A bed which had been 

 used for sowing the seeds of tender plants in pots, and in which 

 charcoal ashes were used for plunging them in, was appropriated 

 to receive the newly planted species of ^Vum, Begonia, Ges- 

 ner«, Gloxinia, and Scitamineae. The pots with these tubers 

 were plunged to the rim in the frame containing the charcoal 

 ashes, and then covered over with loose mould from a dung bed. 



Before I proceed further, I cannot refrain from recommending 

 this method, which, to my knowledge, has not been long known 



