expedient of this kind; and although temporary rudders are no new subject, yet the one here delineated is unquestionably the best ever held to public view. Little more need be said in its praise, than the concurrent opinions of seven professional men (whom I know to possess clear judgment) that the rudder was superior to any that could be made at this island, and they had no hesitation in recommending Captain John Peat to proceed on his voyage to Jamaica, without any alteration in it whatever; and I can venture to assert, without hesitation, that the machine in question not only supersedes Pakenham's rudder, which stands in such high repute, but every attempt of that nature hitherto made, and reflects the highest credit on Captain Peat for his progressive improvement upon the rude idea which first presented itself.

The circumstances favourable to the machine are, first, its being composed of such materials as vessels, of any description are possessed of; secondly, the simplicity of its composition superseding the absolute necessity of a carpenter; thirdly, that it may be constructed and put in action, even in a gale of wind, in two, or at most three hours. Its properties are, 1st. that it can be shipped at pleasure without delay, and with very little trouble; 2d. that it cannot, by any shock or violence, be rendered unfit or useless; 3d. that the guy-tackle fall, being brought to the wheel, requires only the same force to steer as the common rudder; that the ship is under complete command, as will appear by the ship's log-book, in all the following cases:

"Gale of wind, heavy sea, wind quarterly.”

Light winds, heavy swell."

"Fresh wind, spanker, main-sail and all sail, on a wind, off the wind."

The sole object of this, my humble labour, being to pro mote, in however small a degree, the good of the nau tical world; I cannot in justice drop the subject without suggesting what, in my opinion, would be, with little additional trouble, a very great improvement. The body of dead water occasioned by the flat open part x, of the planks at the end of the yard, tends to impede the ship's progress, and to force the case upwards, which consequently strains the guys when going very quick. The dotted lines at x, Fig. 3, I propose to be a piece of plank to be continued on the end of the topsail-yard, so formed or filled up as to carry off the body of water complained of. (Signed) ANTHONY LOCKWOOD.

On the proper Construction of Hot-bed Frames. By THOMAS ANDREW KNIGHT, Esq. F. R. S. &c. With an Engraving.

From the TRANSACTIONS of the HORTICULTURAL SOCIETY of LONDON.

THE most ignorant gardener would feel himself offended, were his skill in making a Hotbed, or giving proper directions for the form of a forcing frame, called in question; and this, perhaps, is the principal reason why the structure, and frames of all Hotbeds are so perfectly alike. The surface of the bed is made perfectly horizontal, and to give some degree of elevation to the glass, that end of the frame, which is to stand towards the north, is made nearly as deep again as the other; so that if the mould were placed of the same depth, (as it ought to be) over the whole bed, the plant would be too far from the glass at one end of the frame, and would want space at the other. To remove this inconvenience, I tried, several years ago, the effect of placing the Hot

bed

bed on an inclined plane of earth, elevated about 15 degrees, making the surface of the dung and mould parallel with it, and adapting the form of the frame to the surface of the bed, as represented in the annexed sketch; Fig. 8 (Plate IV.), by which means the plants and the mould of the bed became more exposed to the influence of the sun. And as I have not discovered any disadvantages in the plan- I have adopted, I have thought a description of it worth sending to the Horticultural Society; for though the improvement be trivial, it is not attended with any expense whatever, since the frame, when made as recommended, costs considerably less than when it is made in the form at present used: and as labour and expense to a very great amount are annually employed in making and managing Hotbeds, any improvement in their construction becomes of some importance to the market gardener.

I have often used, with great success, a frame and Hotbed thus formed for forcing grapes, by placing the bed at three feet distance from the wall, to which the vines were trained, and introducing their branches into the frame, through holes made at the north end of it (the vines having been trained to a south wall) as soon as the first violent heat of the bed had subsided. The white Chasselas grape, thus treated, ripens in July, if the branches of the vine be introduced in the end of April; and a most abundant crop may be thus obtained; but the necessity of pruning very closely renders the branches, which have been forced, unproductive of fruit in the suc ceeding season; and others, from the wall, must consequently be substituted. I have always put a small quantity of mould in the frame, and covered it with tiles.

If an inclined plane of earth be substituted for the Hotbed, and vines be trained in a frame adapted to it,

the grapes (the Chasselas) ripen perfectly in August, and if small holes be made through the sides of the frame through which the young shoots of the vines can extend themselves in the open air, a single plant and a frame of moderate size, will be found to yield annually a very considerable weight of grapes. For this purpose the frames should not be more than eight or ten feet long, nor more than five or six in breadth, or the young shoots will not be so advantageously conducted out of them into the open air; and the depth of the frame, either for the hotbed or inclined plane of earth, should not be less than eighteen inches. The holes in the side of the frame, through which the young shoots are to pass, should of course be closed during the spring, and till wanted; and if the weather be cold, it will be necessary to cover the frames at night. When the grapes are nearly full-grown and begin to ripen, it will also be highly advantageous to draw off the glasses during the day in fine weather, by which means the fruit will be exposed to the full influence of the sun, without the intervention of the glass, and will attain a degree of perfection that it rarely acquires in the vinery, or hothouse,

Description of a Forcing House for Grapes; with Obsercations on the best Method of constructing them for other Fruits. By T. A. KNIGHT, Esq. F. R. S. &c.

With an Engraving.

From the TRANSACTIONS of the HORTICULTURAĻ SOCIETY of LONDON,

So

O much difference of opinion prevails amongst gardeners respecting the proper forms of Forcing Houses, that two are rarely constructed quite alike, though in

tended

tended for the same purposes: and every gardener is prepared to contend that the form he prefers is the best, and to appeal to the test of successful experiment, in support of his opinion. And this he is generally enabled in some degree to do, because plants, when properly supplied with food and water and heat, will succeed in houses, the forms of which are very defective; and proper attention is not often paid by the gardener, when his prejudices satisfy him that his labours cannot be successful. It is, however, sufficiently evident, that, when the same fruit is to be ripened in the same climate and season of the year, one peculiar form must be superior to every other, and that in our climate, where sunshine and natural heat do not abound, that form, which admits the greatest quantity of light through the least breadth of glass, and which affords the greatest regular heat with the least expenditure of fuel, must generally be the best and if the truth of this position be admitted, it will be very easy to prove that few of our Forcing Houses are at present ever moderately well constructed. I therefore think that if plans and descriptions of such Forcing Houses, as theory and practice combine to prove to have been properly constructed for the culture of every different species of fruit, were published by the Horticultural Society, much useful information might be conveyed to the practical gardener: and under these impressions I send the following description of a Vinery, in which the most abundant crops of Grapes have been perfectly ripened within less time, and with less expenditure of fuel, than I have witnessed in any other instance.

It is well known that the sun operates most powerfully in the Forcing House, when its rays fall most perpendicularly on the root; because the quantity of light, that glances off without entering the house, is inversely pro portionate