as lately proposed a new method of aining fruit-trees, the object of hich is to communicate permanent ealth and vigour, and the power of fording a succession of abundant ops, by promoting an equal distriition of the circulating fluids. As e cannot convey to our readers a stinct account of this ingenious meod, which is not only founded upon eory, but sanctioned by successful actice, we must refer them to the ransactions of the Horticultural Soety, vol. i. Captain Ball of the royal navy has ide a considerable improvement on chors, to render them more duble and safe for ships; and has also vented a double fish-hook, for preating the accidents which so often ppen both to the ship and the crew the common method of fishing the hor. This improvement consists ncipally in the forming and fixing shank of the anchor to the stock. le stock is made of two pieces of bolted together, and well secured hoops, in order to prevent the anor-stock from slipping off the shank. small square projection was in the nmon way formerly forged on the nk; instead of this small projec, Captain Ball proposes to exd it on each side of the shank so as to receive two bolts through h of these extensions. These bolts d firmly together the two pieces imber which form the stock, and s secure the stock fast to the ik of the anchor. Captain Ball rewarded with the silver medal by Society of Arts, in whose Transac s for 1808 a drawing and descripof the invention will be found. A simple process for hardening the ace of casts made from plaster of s was communicated to the Soof Arts. The cast is boiled for fifteen minutes in a solution of one pound of alum and a pint of water, and is then permitted to dry gradually for a month, by which means the cast acquires a considerable degree of hardness on its surface, and is even capable of receiving a polish by friction, so as to resemble white marble. A contrivance for preventing doors from dragging on carpets, and for excluding the current of cold air which enters under such doors as are not close to the carpets, has been invented by Mr John Tad. A slip of wellseasoned beech wood, equal in length to the width of the door, and about an inch and a quarter wide, and half an inch thick, is covered with green cloth on the inside, and is hung to the bottom of the door by three small brass hinges. As the door opens, it is drawn up by a concealed spring, and when the door shuts, it is forced down by one end of it, which is semicircular, pressing upon a concave semicircular piece of hard beech wood fastened at the bottom of the door case, and which holds it down close to the floor or carpet, in order to prevent the air from entering under it. See the Transactions of the Society for the Encouragement of Arts, &c., for 1808. A floating tube for viewing objects. under water, and a floating telescope for the same purpose, have been invented by Dr Brewster of Edinburgh. About two years ago, the Royal Academy of Sciences at Copenhagen offered their mathematical prize for the invention of a hydraulic tube, by means of which objects might be distinctly seen at the bottom of the sea. The construction of such an instru-. ment is obviously limited by certain conditions. If the sea is ruffled, or in a state of agitation, it is manifestly impossible to see the objects below by any instrument which is not immersed in the water. Even when the surface is perfectly smooth, and the objects below sufficiently illuminated, they can be perceived distinctly only when the visual line forms a very considerable angle with the surface. It is possible, indeed, to have a contri-. vance which will counteract the oblique position of the surface with regard to the axis of vision; but as the correction must always vary with the angle of obliquity, and must be adapted to that angle, it cannot be applied in practice till the inclination of the visual line to the surface of the water has been previously ascertained by a geometrical operation. No instrument, therefore, for seeing objects under water can be of any service in which the rays proceeding from the objects below must be transmitted through the surface of the fluid. Hence it becomes a necessary part of the construction, that the instrument shall be partly immersed in the water, and that it shall either float by itself, or be attached to some floating body. Admitting this, therefore, as a principle indispensably requisite in an instrument of general application, it may be thus constructed:-A tube is inserted into a parallelopiped made of wood, or of hollow copper, which floats in the water in such a manner that one half of it is below the surface. Near the lower extremity of the tube is fixed a piece of well-polished plate glass at right angles to the axis of the tube, and cemented to it so as to resist the admission of the water. When this apparatus is plunged into the sea, the floating parallelopiped will keep the tube in a vertical plane, and by moving it round a pivot, it may be directed to any object at the bottom, which will be seen as distinctly as if the surface of the water was perfectly smooth, and the eye placed directly above the object; by this means the irregularities arising from a broken or agitated surface, or from the oblique position of the surface when it is per fectly smooth, are completely remo ved. If the depth of the water is so great, or the objects so small, that the assistance of the telescope is necessary to perceive them distinctly, the tele scope may be fixed in the floating pa rallelopiped, and used as formerly. It is obvious, however, that the focal length of the object-glass will be lengthened, and, therefore, that the telescope must have a longer tube than is required for common purposes. When the objects at the bottom are obscure, so as to require artificial illumination, this may be effected by means of a second tube, with a plate of glass at its lower extremity, through which the light of a lamp is thrown upon the objects. This instrument may be constructed in such a way as to examine objects situated below a projecting rock, or beneath a boat or vessel, in which the observer may be placed. The principle on which the prece ding construction is founded, may be employed with considerable advantage in microscopical observations. In per using the writings of those naturalists who have applied the microscope to the examination of minute objects, w shall find that the most perplexing and difficult part of their labour co sisted in preserving the insects a substances which they wished to ex amine. Small insects instantly shrive up, and lose their natural form soon as they are killed; and the m nute parts of plants suffer a simil change from exposure to the air. Hence Swammerdam and Lyone killed the insects which they exami ned, by suffocating them either in water or diluted spirits of wine. The softness and transparency of their parts were thus preserved during the process of dissection, and when they were completely unfolded, the insect was allowed to dry before it was presented to the microscope. Its parts were consequently contracted, and lost not only their proper shape, but that plumpness and freshness of colour which they possessed when alive. In order to remedy this evil, insects and other microscopical objects should be plunged either into water, or in diluted spirits of wine, conained in a glass vessel, and the object glass of the compound microsCope, or the lens of the single miroscope, should also be immersed in the same fluid. The weight of the superincumbent column will press the fluid against the lens, and the substance will be seen with perfect distinctness while its parts preserve their natural form, and receive from the liquid that transparency of colour which is so essential to an accurate examination of minute objects. If the specific gravity of the sub, stance should happen to be less than that of the fluid, it may be preserved from rising to the top by a piece of hin parallel glass, or a small grating of glass fibres, or fine silver wire stretched across the vessel. Captain Bolton, of the royal navy, as lately proposed an improvement n jury-masts, for which he received he silver medal from the Society of Arts. They are formed from the pare spars usually carried on board king's ships and merchantmen. By neans of jury-masts constructed in this way a vessel will be enabled to carry as much sail as with the usual regular mast; hence this contrivance may be of great importance to fleets after a general action, or when they are in want of proper lower masts, either at home or abroad. A drawing and description of this invention. will be found in the Transactions of the Society of Arts for 1808. An improved screw wrench, to fit different sized nuts or heads of screws, has been invented by Mr William Barlow of his Majesty's dock yard, Portsmouth. This wrench is, by means of a nut and screw, adjusted with the greatest care to the exact size required, and in this state it is so steady, that it has been found equal to a solid wrench. See the Transactions of the Society of Arts for 1808. A very ingenious apparatus for yoking horses in thrashing machines, by which they are made to draw or work equally, has been invented by Walter Samuel, blacksmith at Niddry, Linlithgowshire. The horses are so connected to each other by means of ropes and shifting blocks, that the power of all of them is united. If one of the horses relax, another of the horses instantly takes up his rope, and pulls the collar close to his shoulders, so that the former must either exert himself or be pulled backwards. This apparatus can easily be added to any thrashing machine, either when the horses are yoked to low levers, or to limbers fixed to levers placed above the horses' backs. It has been proposed to apply this invention to horses yoked in carriages, but this has not yet received the sanction of practice. An ingenious blow-pipe has been lately prepared by Mr Farey, junior. It is constructed on the same plan as the great blowing engines for iron furnaces. In this instrument it is not necessary to blow constantly with the mouth, for if the air is forced out of the receiver at intervals, the pressure of the water will expel it in a con stant stream, and the operator may take his mouth from the pipe at any time for a few seconds, without in terrupting the current of air. See Edinburgh Encyclopædia, article BLOW PIPE. A very ingenious method of employing a high fall of water for driving machinery, but particularly thrashing-mills, has been invented by Mr Gladstanes of Castle-Douglas. It resembles exactly the common chainpump, which consists of a chain of buckets revolving round two wheels. The water is introduced into the buckets, so that one side of the chainpump being completely loaded with water, the two wheels upon which it moves are thus put in motion. In cases where the quantity of water is small, this contrivance is much superior to an overshot wheel. The buckets continue full in every part of their descent, and when the machine works in back-water, some of the buckets may be taken out, and the lower wheel raised out of the tailwater. This contrivance can also be executed at much less expence than an overshot wheel of the same power. A machine for beating out hempseed and flax-seed has been invented by Mr Ezekiel Cleill. The seeds thrashed by this machine are not so much bruised or injured as by the common way, and the hemp and flax are preserved from any injuries which they suffer from the old method. See Transactions of the Society of Arts, vol. xxv. A very ingenious machine for cutting wood for the purpose of veneering has been constructed by Mr Brunell, the inventor of the block machinery. The hardest kinds of wood are cut into thin boards, by means of sharp steel cutters held together and fas tened by means of screws to a frame. This frame, when properly adjusted, is put in motion, and forces the cutters against the board till the veneer is entirely separated, without the smallest loss of wood. See Repertory of Arts for 1810. An economical method of evapora ting the water of brine springs has been invented by Mr Dubutat, and has been employed with great success for twenty years, at the salt works of Moutiers, in the department Mont Blanc. The water is convey ed by troughs to a large reservoir, where it is left to settle; and thence it passes through other troughs to gradation-houses, about 1100 yards lower down. In its course, it gives out bubbles of carbonic acid gas, and deposits a reddish sediment, which is at first oxide of iron, then a mixture of this with carbonate of lime, and at length almost wholly calcareous carbonate. It passes through four gradation-houses in succession, and comes out of the last at the strength of 18°, and sometimes more; it is then boiled for about 26 hours, or til the salt begins to crystallize, keep ing the boilers constantly full; a foulness that rises is scummed off, and the sulphate of lime which it contains is precipitated. The sulphate of lime being raked out, in winter the evaporation is con tinued with a slow fir till the whale of the salt is deposited; but in summer a different process is followed, by which all the fuel consumed in the last stage of the operation is saved. When the solution is brought to the point of saturation, it is convey ed to a reservoir, whence it is raised by a chain-pump to a trough at the top of a wooden building, and ex tended its whole length. From this trough it runs into a series of very narrow troughs at right angles to it, and about two yards long; to each of these belong 25 double or endless ropes, 24 lines in diameter, five inches from each other, and fixed 26 feet below. The saline water flowing constantly out at notches cut in the sides of the troughs, trickles down the ropes, round which it forms a very thin coat, displaying a considerable surface to the solvent power of the air. As the water evaporates, the salt is deposited on the ropes: The water that flows down runs into the reservoir, and is pumped up again repeatedly till it is exhausted, when it is suffered to run into the bason that contains the mother-water. The water of a fresh boiling is treated in a similar manner, and seventeen boilings are thus raised in succession, forming one making, which occupies 40 and 45 days. At the end of this period, the ropes are encircled with a cylindrical covering of salt 2.75 or 3.15 English inches in diameter, which is broken off by an instrument made for the purpose. As the preceding process can be performed only in summer, two makings only take place in the course of a year. Every boiling before it reaches this building, deposits 2205 pounds of salt in the boilers, while about 14332 pounds are taken from the ropes, the whole produce of one boiling being about 17332 pounds. This process does not yield so much salt as the one commonly used, for the product of the evaporation of a si. milar quantity of water by two boilings would be 17332 pounds; but, what is of greater consequence, the salt itself is obtained more pure, and there is a very considerable saving of time and labour as well as of fuel. See Journal des Mines, No. 120. A new anemometer, for measuring the force and welocity of the wind, VOL. II. PART I. has been invented by Dr Kirwan. A piece of wood, one foot square, is exposed to the action of the wind, and is covered over with very thin sheet brass, strongly painted and varnished with copal; this piece of wood is fastened at right angles to a sliding horizontal rod, which moves in a wooden pipe or tube 2 inches square, fastened on the top of an upright pole: This sliding wood moves upon brass rollers, and when it is pressed into the tube by the action of the wind upon the wooden frame, it raises a string attached to a number of weights, one pound avoirdupois each. When the wind blows with small force, one or two of these weights are only raised, and when the wind blows with greater force, a greater number of the weights is raised, the number of weights raised being always a balance to the force of the wind upon the wooden frame. Though this instrument will evidently act as an anemometer, we can by no means admire the contrivance by which a variable resistance is opposed to the action of the wind. This has usually been done by the compression of a spiral spring, or by the elevation of a weight round a centre acting at the arm of a variable lever, and we cannot allow ourselves to think that the contrivance of Dr Kirwan is in any respect an improvement upon these instruments. The compression of a bag of air, and the weight of a column of water, have been successfully employed to measure the resistance of the wind. We conceive, however, that a variable resistance arising from the elevation of a solid out of a fluid lighter than itself, or from the depression of a solid into a fluid heavier than itself, will be found of considerable advantage in the construction of anemometers. A complete 2 F |