and calculations; for, were this known, we should at once have a rule for erecting an apparatus for houses of any dimensions. Until this be established, the following "rule of thumb" plan, which I have just adopted, will answer. (Fig. 53. A B.)

A, Section of the boiler, showing the second range of pipes (bc). Suppose them all to be 4-inch pipes, the height of the boiler would be 32 in., allowing 4 in. between the pipes. It should be of copper.

B, The new valve, which should be of copper or brass, and made exactly to fit the boiler. For the above boiler, it should be 18 in. long, and have two circular holes (ff) cut in it of the diameter of the pipes, so that when it is pushed down into the boiler the holes may be opposite the pipes. This portion of the boiler, and the valve, should be nicely ground together, but not so tight, but that the latter may be turned round by the handle (e, and in fig. D, i) at the top. There is also an opening left at the top to allow the steam to escape, and not endanger the vessel by bursting.

c, The top of the valve (D). The arrow points directly over the holes, so that should it be turned for the purpose of closing the pipes, the exact proportion closed is visible; and to entirely shut the communication, the head of the arrow should be the contrary way of the pipes.

D, The new boiler, with the valve half drawn up; the bottom is larger and concave (say 18 in. diameter) to receive more heat, and the returning pipe () is 4 in. above the bottom. If the pipes are 4 in. diameter, the boiler from m should be 12 in. diameter, and 20 in. high from the top to the bottom, i. e. from n to n.

k, The delivering pipe.

E, The lateral pipe, with a part enlarged to admit the valve (which is of brass) to open to the diameter of the pipe.

s, The valve placed diagonally, so that its own weight may shut it. A collar of brass is soldered to the pipe, and ground to fit the valve, so as to be water-tight.

r, The hinge.

t, Wire attached at the bottom to open it; this wire passes through a small tube (q), and may be fastened in any way most convenient.

The dotted lines represent the valve open. The small tube should be as high as the top of the boiler, otherwise the water would escape through it. The proportions mentioned are only as general guides, and the drawings are not to any scale.

Concluding that my sketches are understood, I will detail their application. The apparatus being filled with water, you close the valve, and the lower pipes gradually become heated (thus far is the old apparatus); but should you require more heat, by turning quite round the valve, or only half turning it, as may be required, the hot water at the top of the boiler instantly forces the cold water out of the upper pipes, and you have a second range of hot pipes, and by the use of the valve you may regulate this heat at will. I would also have above the second range of pipes, a sufficient space to allow of a third range, should it be found requisite; and this can be done by having shoulders made in the boiler, as represented by dotted lines (u x), and these orifices closed with plates of tin or copper, which (should a third range be required) could easily be unsoldered, and the pipes adjusted without altering any portion of the original apparatus. Through the summer, the second range, probably, would not be required, and by having a cock in any part of the apparatus, the water may be entirely drawn off, so as to leave them empty, the boiler then having only the lower or original range to heat.

These hints (which I cannot but flatter myself are valuable), perhaps, best apply to such apparatus as have failed in producing, through this severe winter, the requisite temperature; but should we know what quantity of pipe (or properly water) will heat a house, the single range can be used; and then, for the purpose of regulating the heat, I would recommend the valve and boiler D, which, closing the pipes in part or altogether, must produce whatever temperature you require. I am speaking of an apparatus possessing the power alluded to in the former part of this communication.

Before the above occurred to me, I had a valve made (s), which I fitted into a glass 1-inch tube, and adjusted it to fit one of my lateral pipes (fig. 4. p. 20.); the glass tube was 3 ft. long, and was introduced in the place of the metal pipe, for the purpose of observing the motion of the water. This little apparatus answered very well, although it was not entirely cold, as it received heat at the end of the pipe b (fig. 4. p. 20.), but when the valve was open, its effect was almost instantly perceptible, not only by the motion of the water, but by the additional heat.

I cannot allow this letter to go to you without detailing my method of applying the hot water. Necessity is the mother of invention; and when I was about removing my plants, I could not take down my hot water apparatus until my plants were removed, and I could not remove the stove plants until I had a proper receptacle for them. Accordingly, I built a pit after

Mr. Stewart's plan (Vol. I. p. 71.), only so arranging my fireplace, that it would heat the boiler of my hot water apparatus in the pit adjoining. By this plan, I have an excellent and steady heat produced at no expense; for I must have had a perpendicular flue for my boiler, instead of which I have placed it horizontally, and applied the heat of the flue to the house. Finding how well Mr. Stewart's pit worked, I, in part, abandoned my lateral pipes, and have made (in my hot-house) floors over the pipes, on his plan, filled with sand, and find the whole to succeed in the most delightful manner imaginable; the temperature of the sand being from 76° to 80°. The advantage of the hot water over the fire flues is, that you cannot over-heat your sand, and the temperature is more uniform, and will continue several hours after the fire is out. I think I cannot be here out of place, in offering my best thanks to Mr. Stewart, for the hint which his communication has afforded me.

It may be satisfactory to some of your readers to know, that I have even made the water boil in the apparatus (a) whilst the valve was closed, so that only the lower pipes were at the boiling point, and of course the water, to the top of the boiler, but the upper range of pipes were almost cold; the pipe (c) was quite cold; the pipe (b) received a slight portion of heat close to the boiler, but I consider it to arise from absorption. Whilst the apparatus was in this boiling state, I turned the valve half round, and in six minutes both pipes were heated, as well as a small reservoir attached to them at 7 ft. distance. The hot water, therefore, displaced all the cold water in the reservoir, and in 14 ft. of pipe, in the space of six minutes. I am, Sir, &c.

Mount Pleasant, near Swansea, April 23.

ROBERT BYERS.

ART. VII. Notice of a durable Number Tally of Earthenware. By Mr. WILLIAM ANDERSON, F.L.S. H.S. &c. Curator of the Chelsea Botanic Garden.

Sir,

A DURABLE numbering tally has long been a desideratum in the nurseries and botanic gardens. The late Mr. W. Curtis, author of the Botanical Magazine, procured a label of Wedgewood-ware; it was very clean and showy, but did not stand the frost. Within these two or three years, we have

seen iron tallies of various shapes, but their being so near the ground, and their exposure to wet and frost, proved very injurious to them. In the young-tree quarters of the nurserygrounds, spokes of old wheels are made use of for this purpose; but in hard winters, we have known of some hundreds of these sticks being carried off in a night for fire-wood. In the botanic garden here, as every where else, the numbering sticks are liable to the injuries of frost and rain, and although the wood may endure for ten or twelve years, the tallies require painting every four or five years.

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109

To obviate these defects as far as possible, we consulted with our potter, Mr. James Marshall, of Norwood, in Surrey, who engaged to provide us with 5000 at 14d. each, in order to renew the sticks of our herbarium department. These tallies (fig. 54.) are made of the same clay as garden pots, and Mr. Marshall says he can make them at 8s. per hundred, having procured the moulds, &c. The top of the tally being bevelled off in the manner of a writing desk to receive the number, and having had four coats of good white lead paint, it will be washed by every shower; and should we find that the wet gets under the paint, we have only to continue the paint down 3 or 4 in. Respecting the strength of these tallies, 2600 came in the first cart load, and although they were laid upon one another without package, there were only fifteen of them broken. They are from 11 to 12 in. in length, 2 in. in breadth, 14 in. thick, and the size of the bevelled part is 1 in. I remain, Sir, yours, truly, Botanic Garden, Chelsea, Feb. 4. 1829.

W. ANDERSON.

ART. VIII. On Landscape-Gardening, as a Part of the Study and Business of Practical Gardeners. By a LANDSCAPE-GARDENER.

(Concluded from p. 42.)

WITH respect to the distribution of such plants for the purpose of thickening the interior, or enriching the margins, of woods, they should be disposed in very irregular parts, to produce not only a general screen, but also an intricacy of outline of themselves; sometimes advancing beyond the exterior, or retiring back towards the middle, of the wood. Views into the wood may be marked or bounded by the

undergrowths; care being taken that the eye does not see through it, except for the sight of some suitable object.

Open groves may be greatly improved by a judicious disposition of such undergrowths. Insulated groups of trees should always have a base of holly, juniper, and whitethorn; the latter is an excellent protector of the honeysuckle roses, or any other climbing plant; even single trees are improved in character and appearance, when they give protection to an humble neighbour.

When the woods and groups of the park are thus planted, the naked baldness so often complained of will be remedied; the detached parts will be better connected; the hard profiles of clumps softened; and the whole will then partake of the semblance of the more dressy features of the pleasure-ground, an advantage of no small importance.

In forming new plantations of forest trees, the above directions (which are all plain practicable matters) are easily executed; it is only sowing the ground with the seeds of the undergrowth, after the principal trees are planted: the whole will then rise together, and yield many supernumeraries for other purposes. Old scenery may be improved by transplantation, or sowing the seeds of the kinds above mentioned; but this requires much more care and expense than when done at first.

Before concluding these observations, it may be necessary, perhaps, to advert to the different characters of trees as belonging to the different descriptions of scenery hereinbefore specified; a view of the trees themselves will give better ideas than the most lengthened description.

Beautiful Trees.-Among these the deciduous cypress (Cupréssus dísticha) is perhaps unrivalled; the mild tint and soft wavy tufts of its delicate foliage, the elegant ramification of its branches and spray, and the light feathery appearance of its general form, mark it as a tree of singular beauty.

The

bark, though dark brown and rather rough, contrasts agreeably with the gay verdure of the foliage, and it is altogether a plant deserving the most conspicuous place in the most dressed

scene.

Partaking of the same characteristics, in a greater or less degree, the following are preferable, viz. the acacia (Robínia Pseudacàcia); weeping willow (Salix babylónica), where the climate or situation is favourable; white hiccory (Juglans álba); ailanthus (Ailántus glandulòsa); storax (Styrax officinale); weeping birch; common lime; common beech; Weymouth pine; white cedar (Cupressus thyöìdes); red cedar (Juniperus virginiana); and the common ash, when young. Most of these associate