destruction of the Mealy Bug and Scale. 433 



may have been ordered, about two hundred and fifty well- 

 grown and well-flavoured pines yearly, for the last fifteen years ; 

 and were my system more generally adopted, where leaves are 

 plenty, even if coals were cheap in the neighbourhood, it 

 would do away with frequent quarrels between the bailiff, or 

 farming steward, and the gardener. If any further communi- 

 cation relative to what I have said be required, I will attend 

 to it; or should any thing occur to me, I will, with your 

 leave, send it, but I will not enter into any paper war, such as 

 Mr. M'Murtrie's with my friend Agronome, in p. 98. 



I am, Sir, &c. 

 Wi7npole Gardens, Jan. i. 1829. James Dall. 



We request our readers will turn to Vol. III. p. 183., and 

 mark the great simplicity and cheapness of Mi\ Dall's method 

 of pine culture, and that this method is without any other 

 heat than bottom heat : consequently, the most opposite pos- 

 sible to that of Mr. Knight. Not that we deny that pines 

 may be grown vi^ithout bottom heat, or even without being 

 plunged or planted in a bed, and, with great care, perhaps well 

 grown ; but we have always denied, and still deny, that they 

 can be so grown, either with the same ease and economy, as 

 in a bed of fermenting material, or to such a large size. Our 

 words, written in the year 1822, as given in the JEna/clopcsdia 

 of Gardening, § 2933-5. are as follows : — 



" To draw any conclusions in the present stage of Knight's experiments 

 would be premature, and it might excite prejudice to anticipate the final 

 result. That the pine plant will grow and thrive, without what is tech- 

 nically called bottom heat, is an obvious truth, since no plant in a state 

 of nature is found growing in a soil warmer than that of the superincum- 

 bent atmosphere. But, to imitate nature, is not always the best mode of 

 culture; for the more correct the imitation, the less valuable would be the 

 greater part of her products, at least as far as horticulture is concerned. 

 What would our celery, cabbage, and apples be, if their culture were copied 

 from nature ? Though the pine-apple will grow well without bottom heat, 

 it may grow with bottom heat still better ; and though the heat of the 

 earth, in its native country, may never exceed that of the surrounding at- 

 mosphere, it does not follow that earth heated to a greater degree may not 

 be of service to it in a state of artificial culture. But, admitting, for the 

 sake of argument, that the pine plant could be grown equally well with, as 

 without, bottom heat, still it appears to us that the mass of material which 

 furnishes this heat, will always be a most desirable thing to have in a pine- 

 stove, as being a perpetual fund of heat for supplying the atmosphere of the 

 house in case of accident to the flues or steam-apparatus. Besides, it ap- 

 pears from nature, as well as from observing what takes place in culture, 

 that the want of a steady temperature and degree of moisture at the roots 

 of plants is more immediately and powerfully injurious to them than atmo- 

 spheric changes. Earth, especially if rendered porous and spongelike by 

 culture, receives and gives out air and heat slowly; and while the temperature 

 of the air of a country, or a hot-house, may vary twenty or thirty degrees 

 in the course of twenty-four hours, the soil at the depth of two inches 

 Vol. V. — No. 21. f f 



