THE application of hot water to the heating of horticultural structures, was a long step in the advance of progress. Since then, efforts have been constantly made to improve on and simplify the principle, so as to obtain the greatest results at the smallest possible cost.

The Waltonian Case, of which we give herewith, cuts from the Cottage Gardener, is one of the latest improvements, the chief feature being that the water is heated by a lamp, instead of an ordinary fire. It seems to answer its purpose very well, and will be quite the thing for many of our amateur friends, while the principle on which it is heated will afford a hint to many of our more professional readers.

Mr. Beaton, one of the most practical of English gardeners, thus speaks of its success there: -

"I must repeat, that I never saw a better contrivance for amateurs to strike cuttings and raise seedlings with than this of Mr. Walton's, and that there is not a better mode in existence as far as I am aware of. There is nothing better in any of the London nurseries I have seen; nor at any of the botanic gardens; nor, in short, anywhere.

Hot water, without circulation, is now proved to be as good, on a small scale, as it is by circulation on a large one. Mr. Walton's first idea was to apply the heat of a lamp, or gas jet, to the bottom of a tin can, by means of a double bottom or "false bottom," and on that principle his own Case is still worked. In the present form of it, the heat is brought direct into the body of the water in a zinc tube, coiling round and round, then out through the back of the Case, to carry off the smoke and smell; and the principle is the same as that by which the water in the basins in the Crystal Palace is. kept warm; hot water-pipes heat the water in the basins, and a zinc pipe heats that in this apparatus, being heated itself either by gas or oil. But, where gas can be applied, I would recommend it as far preferable to a lamp, because there is no bother about snuffing, trimming wicks, or keeping a lamp clean. A lamp must be trusted to a servant when the master is out, and if he neglects it, your batch of cuttings may be dead and gone before you come home.

But as gas cannot be had everywhere, I subjoin Mr. Walton's description of his own Case, with sketches to illustrate the working, premising that his fears about the draught from the lamp through a coil of tubing were groundless when the gas was applied, and that nothing acts more satisfactorily "with a very small jet of gas. Neither is it necessary to begin with hot water if that in the tin case should get cold at any time. Also, that what he means by the lamp burning for eight hours, is not that the half pint of oil is consumed in that time, but that the lamp requires trimming at the end of eight hours".

Mr. Walton, the inventor, thus describes his Case:- -

"The box I used was an old one, to which I added a top, so as to give an inclination, as in a garden frame. Half way down, in the inside, a moulding is nailed, on which the zinc frame rests. The pots are placed on the zinc frame. The boiler is of tin, surrounded by a false cover of tin, which I found necessary to create a draught for the lamp. A small chimney runs from the inner boiler, through the false cover, into the frame; and, although the water does not boil,. the steam, or moisture, keeps the frame damp. The false cover has a chimney which runs through the frame and but at the back, to carry off the smoke, if any, but there ought to be very little. The lights are divided into three, and are merely fixed in zinc frames, not wood, and let into the top, to lift on and off, or tilt. This is better and cheaper than glass in a wood frame, as the water (why, I cannot tell) does not drop inside, but rests on the outside, and may be tilted off. The lamp was made by Smithurst, of Bond Street, but is quite plain and circular, holding more than half a pint of Colza oil. It must be well trimmed, so as not to smoke, and then will burn eight hours. A tin lamp will do just as well.

The smoke does not get at the plants, but would collect at the bottom of the boiler, and fall on the lamp.

"The lamp is three inches high, and four inches across. If trimmed at night, it will be alight in the morning, and should be trimmed in the middle of the day. If the lamp should go out, and the water become quite cold, draw off some and add hot water, otherwise the lamp will not burn. I have raised from cuttings, Roses, Verbenasy Fuchsias, and Dielytra spectabilis, and it is excellent for forcing seeds of all sorts. Mr. Beaton, our gardening authority here, says it will raise anything that can be raised by heat, as it is so clean and moist. He has suggested an improvement, which I intend to try; which is, to do aw+y with the outer tin case, and to insert, at the bottom of the boiler, a coil of zinc tubing, and to carry it out through the case as my smoke is now. This would be more simple, but I very much doubt if the lamp would have sufficient draught to burn. Mr. West, the ironmonger here, has made them complete for 35*.; but he could make the boiler apparatus, tin lamp, etc., separate, and you could have the zinc tray and box made in the country to fit the boiler".

The following description of one by Mr. Beaton, will fully explain the structure in all its details. It is no doubt capable of many improvements, of which out "Yankee genius" will not be slow to avail itself: - "My lamp is copper, but tin would do as well. It has an extra head to burn three wicks instead of one, which add much to the heat, but I found one sufficient.

The lamp holds more than half a pint of oil, is three inches high, and four inches across. "The best size for the box is thirty-four inches long, seventeen niches wide, thirteen deep in front, and eighteen inches at the back, all inside measure. Such a box will hold three rows of No.48 pots, and six pots in a row; or four rows of No. 60, and eight pots in the row. When making a smaller, or a larger box, one ought to fix on how many of those two sizes of pots the box would hold conveniently without loss of space. An amateur should never use a pot larger than a 48 for striking cuttings, and that size is large enough for all his seeds. The tin case to hold the water should not be less than four inches shorter or Narrower than the box inside, which leaves two inches between the tin and wooden boxes at the ends and sides, and it should be four inches deep; then, when the heat is raised to 80° or 85°, it matters not if the lamp, or jet of gas, should go out for some hours, or as long as the heat keeps up to 70°. If the size of the tin box is so small that the body of water in it is not sufficient to keep up the heat for several hours without a constant burning of gas, or oil, the first expense will be less, but the disadvantage would be in greater proportion, The lid of the tin case is made in the shape of a tray, with the edges raised about half an inch, so as to hold sand on which the pots stand; a tube, five or six inches long, and about an inch in diameter, is soldered to the lid to let up vapor, not steam, from the hot water, so as to keep the air sufficiently moist for the health of the cuttings or seedlings.