Count Zubow, at St. Petersburg, employed steam to heat a pit or cistern of water, over which, at about three inches distance, a frame, covered with faggots, was placed, and on this was laid the earth, in which his Pines and other exotics were planted without being in pots. The plan is said to have succeeded, and a wholesome temperature to have been obtained and communicated to the mould above the faggots. Mr. Gunter, as before observed, (Chap. IV. sect. 13.) had already tried the use of steam as a bottom heat without success. Mr. John Hay, horticultural architect, tried the use of steam so early as 1794, when gardener at Preston Hall, near Edinburgh, and he gives the following account of his apparatus and success in the Memoirs of the Caledonian Horticultural Society. “The application of steam to forcing-houses early caught my attention. The first that I designed and executed in Scotland on this plan, were at Preston Hall in Mid-Lothian, in the year 1794. The fruiting Pine-stove, which is in the general suite of houses, with two peach-houses on the west, were originally adapted to steam. I entertained the hope, that steam thrown into a chamber, in the bottom of the plant pit, would act as a proper substitute for bottom heat in place of tan, as none of that substance was to be found nearer than four miles distant, and when wanted was often difficult to be procured. Other more general considerations also made me desirous of procuring some substitute, particularly the necessity of repeatedly shifting the plants to renew the heat, when the bark in the plant-pit gets cold: these shiftings, besides the trouble, often retard the growth of the plants. Again, if the heat of the fermentation of the tan rise much above ninety-six degrees, (which it often does), and if the pots be fully plunged in the tan at such a time, many instances have been known of the roots of the plants being burned, and some of them being destroyed altogether. This, indeed, may be considered as one of the principal reasons why so many are unsuccessful in the culture of this fine fruit. With the view of obviating the above difficulties, the bottom of the fruiting Pine-pit was constructed with a chamber below, into which steam was introduced by means of copper and lead pipes from a boiler placed in the shades behind: the top of the chamber was constructed of rafters, on which were placed broad grey slates, laid on loose, without filling up the vacancies between them. The not making them close, I afterwards found to be an error; for the moisture, from the condensation of the steam, penetrating through the openings at the joining of the slates, communicated too much wetness to the bottom of the pots; but I found, that there was a sufficient quantity of heat to be obtained from the steam for heating the plant-pit, provided the bottom were close. I therefore discontinued this plan; and I had not an opportunity of making any farther experiment on the subject in this place.