308 Dimensions and Details for Plant Structures, 



limes, ashes, beeches, alders, willows, elms, and firs. These 

 sorts of charcoal were kept separate, and placed in a warm bed 

 in a hothouse, to these a space filled with bone ashes was added. 

 In all the nine compartments leaves of the same plants were put: 

 the eight sorts of charcoal had almost exactly the same effects ; if 

 there were any difference, I would give the preference to the fir 

 ashes. It was very different with the animal ashes : in this little 

 experiment they produced the most favourable results ; many 

 leaves rooted in them which had not succeeded in the charcoal, 

 and some very soon produced shoots. 



I cannot resist saying a few words here, in conclusion of my 

 observations, on the bed formed in the new propagating-house 

 of the Royal Botanic Garden at Munich, built last summer. 

 The house is sunk 4 ft. in the ground, is of an oblong form, and 

 faces the e. s. e. The surface of the bed within is half a foot 

 lower than the level of the garden, and is heated by a simple 

 walled flue, over which a copper pan the length of the bed is 

 placed, from which constant vapour arises, and which communi- 

 cates heat and moisture to the charcoal, with which the whole 

 bed is covered to the depth of 5 in., through perforated boards 

 lying over the pan. The temperature of the water is, on an 

 average from 50° to 60° of Reaumur (145° to 167° Fahr.). 

 This sort of heating by water or steam is, in my opinion, the 

 best method for propagating plants ; and it is to be hoped that 

 M. Seitz, from whose plan the house was built, will follow up 

 his intention of giving a full description of it. I plunged my 

 propagating-box, without a bottom, into this charcoal, and put 

 the better sort of cuttings, and those which are difficult to root, 

 in it. The movable lights were generally taken off during the 

 night, and also sometimes in the day, that the moisture and 

 drops of water might run off and be dried up. I stuck her- 

 baceous cuttings in the bed without further preparation, and 

 almost all of them grew easily and quickly. 



In compliance with the wishes of several of my friends and pa- 

 trons, I intend publishing in a small pamphlet all that has hitherto 

 been known on the efficacy of charcoal, and I have already been 

 promised communications on the subject from many quarters. 



Art. IV. Dimensions and Details for erecting various Kinds of 

 Plant Structures to be heated by Hot Water or Smoke Flues, or 

 by both Modes combined. By Thomas Torbron. 



The kinds of plant structures which I am about to describe 

 have been found good in practice, botii by my late father and 

 myself; and they were also approved of by the late eminent hor- 

 ticulturist Mr. Knight, with whom I had the honour to live as 



