Memoirs of the Caledonian Horticultural Societij. 331 



" I caused the chamber of the steam-pit, which I had erected at Castle 

 Semple two years before, to be filled with stones, those of the larger size 

 below, and the smaller above. About this time I entertained the idea, and 

 suggested it to the late Mr. Harvey, that in such pits, prepared with 

 suitable compost, the pine-apple might be cultivated in the earth without 

 pots, as in the West Indies, by growing the plants for one year in the pit, 

 and bringing them to fruit in the next ; and so on alternately. With this 

 in view, experiments were instituted to ascertain the difference of teinpei'- 

 ature communicated to the soil above, by the chamber without stones, and 

 by the chamber with stones, and its duration. The result was decidedly 

 in favour of the latter method, as it was found to retain the heat much 

 longer than the other, as indicated by the steam-pit thermometer. So far 

 1 was satisfied with the application of the principle which I had long had 

 in view ; and, in order further to try its effects, I caused the gardener to 

 make up a bed of suitable compost in a part of the pit, and desired him to 

 plant in it some of the smallest pine-apple plants he had, such as the 

 suckers from the bottom of the fruit, only a few inches high. On my 

 return to Castle Semple, the following autumn, I was surprised to find 

 that the plants had made far greater progress than I expected, being more 

 than double the size their treatment by the old method warranted me to 

 look for. I may here observe, that, if the plants will grow freely under this 

 treatment, in such pits, I have strong hopes that, by keeping the fruiting 

 plants under a moderate degree of bottom heat, during the winter months, 

 and raising it considerably higher in spring, they would start regularly into 

 fi-uit; and if this were found to be the result in practice, the views I origin- 

 ally entertained on this point would be realised. I now became fully con- 

 vinced of the value and importance of this method of applying heat for the 

 cultivation of ananas, and resolved thereafter to adopt it in all practicable 

 cases." 



Sixty feet of pine-pits are now erected at Castle Semple; and the 

 gardener, Mr. Lauder, states " that the pines are as successful in the 

 steam-pits, as in those wrought with leaves, and with only one tenth part 

 of the expense ; as, in the one case, the plants never require to be removed 

 during the whole year, for the purpose of renewing the heat, while, in the 

 other case, viz. the pits wrought with leaves, they require, he says, to be 

 turned over, and new leaves added five times in the year ; and it takes 

 seven men, for two days each time, to perform this operation, that is, on 

 the two pits. He states, also, that it is his intention this spring (1829), 

 as I recommended two years ago, to plant one half of one of the steam- 

 pits with plants, not in pots, but in a bed of soil made up for them, and to 

 fruit them the summer after the next. The steam, he says, is admitted 

 into the chamber, among the stones, only an hour and a half every forty- 

 eight, which he finds to be quite sufficient to keep up the bottom heat as 

 high as is necessary. During the winter, he has not admitted the steam for 

 so long a period, having only kept the heat to the bottom of the pots from 

 75° to 80° ; but now, as he wishes to start the plants into fruit, he intends 

 to raise it to 90°." 



The following description of a plan and section of a set of 

 pits, erected, in 1824, for Colonel Paterson, Cunnoquhie, for 

 the growth of melons, but which will serve equally well for 

 that of pines, or other hot-house plants, is dated March, 

 1829: — 



" The same letters of reference apply to the corresponding parts, both 

 in the ground plan (^g. 33.) and the section (Jtg. 36.). 



