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16 NOTES AND NOTICES.
own estates. It must be borne in mind that
In all places where these advantages are
New Antarctic Erpedition.—The following par-
The Iron Steamer, “Rainbow ’’—Sir.—Can any
Scientific Associations.—We are glad to observe
Necessi'y of Innestigations in Acoustics.-Sir,
Daguerre's Photogenic Process—Erratum.—
MECHANICS’ MAGAZINE, Vol. xxx1, is now
Office, No. 166, Fleet-street.—Sold by A. & W. Galignani, Rue Vivienne, Paris.
18 cAPT. cARPENTER's vessel. PROPELLERs.
CAPTAIN cARPENTER’s vessel, PROPELLERS.
A vessel-propeller, the same, except in point of position, with that which is the subject of the present article, was brought before the public about a twelvemonth ago, having been patented by a Mr. J. J. O. Taylor. The extravagant statements put forth as to the powers of Mr.T.’s invention in comparison with the common and other paddle-wheels, prevented many from giving it much consideration—a glance being sufficient to convince any one at all acquainted with the subject, of the impossibility of its performing a tithe of the duty for which credit was claimed.
Capt. Carpenter, of the Royal Navy, subsequently improved upon Mr.Taylor's plan. Instead of one propeller under the dead wood of the vessel, Capt. Carpenter employs two, one on each side, near the stern. In this form, and as an auriliary power to that of the wind and sails for sailing vessels, it is well deserving of attention, and, in that character, we now lay it before our readers.
From a prospectus issued by Captain Carpenter, we extract the following statement of the advantages which he believes to be possessed by the plan.
“It has been the opinion of many distinguished naval officers, captains of merchant ships, pilots, and scientific engineers, that the principle upon which I propose to propel vessels, as exhibited on a model, would be of infinite service to navigation, if a similar effect could be produced on a large scale; I have, therefore, considered it my duty, as the subject lies within the precincts of my profession, to demonstrate that principle, so that it may not be lost to mankind. “The Euclid, an experimental vessel, 69 feet in length, has been fitted with this apparatus, from which it can be clearly proved that the propellers would be essentially useful to vessels under the following circumstances:— “l. To vessels that are tacking or veering in a narrow channel, amongst dangerous rocks and shoals, with light variable winds, and a strong current, and require to perform their evolutions with the greatest certainty. “2. To vessels that are becalmed near the entrance of a port, and are desirous of coming to a safe anchorage before dark, and only require to be propelled a short distance to accomplish their object. “3. To keep vessels clear of their anchor.
“4. To assist vessels in casting or winding, and backing astern. “5. To enable a vessel to be steered independent of the rudder, should it be disabled. “6. To assist vessels out of a dangerous position, should an accident occur to their masts or sails. “7. To Indiamen, transports, emigration ships, or other vessels that have many persons on board, this novel apparatus will afford the crew an opportunity of being usefully employed in propelling the vessel a-head during calms, and prevent that monotony, delay, and expense, which ever accompany distant voyages. “8. To vessels that are trading on coasts infested with pirates, and require, in a calm, to direct their broadside towards the enemy, to keep them off. “9. To vessels that are trading up rivers, such as the Gambia, where manual labour is cheap, and tedious calms are prevalent, when the use of the propellers would shorten the passage (probably many weeks), and be of great advantage to the owners. “10. To ships of war, in taking up an advantageous position in action, particularly if opposed to steam frigates in a calm, or concentrating their fire in breaching a fortification. “11. To ships of war, fitted both for sailing or steaming as may be deemed necessary, especially those that are stationed in a blockading squadron, and are required to intercept the enemy, if they attempt to escape in a calm, or in the event of the wind being favourable, possessing the means of topping up the propeller immediately out of the water, and making sail to economise their fuel. “12. To yachts that desire the means both of sailing and steaming. “13. To iron boats fitted for transporting troops across rivers or lakes, worked by manual labour, keeping the men safe under cover from the enemics fire, till they are ready to disembark. “14. To canal-boats for navigating in shallow water, and amongst weeds, where the propelling blades require to be readily cleared, and their action in the water directed so as not to injure the embankments. “15. To steam-vessels generally, that desire to do away with paddle-wheels, and to supply their place by a more safe and effective apparatus, that will give the same speed, and not incumber the vessel or alter the present mode of construction, that will remove the weight and inconvenience of the paddlebox, afford more room on deck, and allow boats to come alongside with safety. “The novelty of the invention consists in the position which has been selected for applying this peculiar propeller, and the manner in which it is affixed to a vessel so as to render it practically useful.” In thirteen out of these fifteen “circumstances,” we think that Capt. Carpenter's propellers would be useful auxiliaries. To the fourteenth and fifteenth, it appears to us they could never be advantageously applied. In canals (to mention one objection on this head) where the water is generally shallowest, viz., towards the sloping banks, it ought, to allow of this propeller being properly effective, to be the deepest. As to its application to steam-vessels generally, as a substitute for the paddle-wheel, we need only point out that the power is communicated to the propeller by a universal joint, and that the propeller acts at a considerable distance from any solid bearing, to convince marine engineers of the inapplicability of the plan. A model of a steam-boat, fitted with
ON ATMOSPHERIC ABSORPTION. 19
this apparatus, has lately been exhibited working on the canal of the Polytechnic Institution. On this toy-like scale the }. works beautifully, but the idea of orming a judgment from such an exemplification is out of the question. A vessel suitable for canal navigation, we are informed has also been constructed, called the Aerolite, of the following dimensions, viz.: length of keel, 65 feet; draught of water with engine onboard, 2 ft. 2 in. ; extreme breadth, 8 ft. 11% in. The prospectus states, that “the efficacy of this principle of propelling has been well tested by manual labour, in this vessel, on the Thames, and on the City canal.” We have not, however, been favoured with any statement of the experimental working of this “test,” which would have given better data for observation than the action of the Polytechnic Institution model.
Description of the figures.
Fig. 1 is a view of the propeller; aa, the blades; b, shaft; c, iron brace; d, topping lift; e, universal joint; f, inner part of shaft.
Fig. 2 (front page) shows the position of the propeller when “topped” up, ready for immediate use.
Fig. 3 shows the position of the pro
eller when the vessel is in the act of i. propelled. Fig. 4 shows the position of the propeller when the vessel is at sea, and under sail. The mode of communicating the power is not necessary to be shown; as that will vary according to circumstances.
Sir, I submit to your numerous readers a few observations upon one of the properties of water, which may lead to
many practical and scientific improve: ments, particularly in the construction of The desiccation of many crystallized salts, for example, sulphate of soda, in a dry atmosphere, happens both at high and low temperatures, and, in either case, the transparent solid crystals, become a dry opaque powder. A remarkable instance of this kind also occurs if cream be frozen into thin sheets and exposed to a dry cold atmosphere, about zero, when the whole of the water of crystallization vanishes, and leaves a fine powder of dry curd and butter. This process is adopted in the higher Swiss Alps, where perhaps churning is found to be impracticable, by placing sheets of iced cream perpendicularly in a frame, like a plate rack, between two open windows, the desiccated cream falling down into a receiving dish, and forming a delicate substitute for butter.
hygrometrical instruments. 2 C
20 IMPROVED MECHANICAL AGITATOR.
I have often noticed the rapid disappearance of snow during a dry black frost, and this seems to depend on atmospheric absorption, for it occurs during the night more than in day light. A fallowed field shall be wholly covered with snow so as to conceal the colour of the earth, and in one night of intense frost it disappears before the morning, without any intervening thaw.
I am, Sir,
ANTHoNY CARLISLE. Langhorn-place, London.
IMPROVED MECHANICAL AGITATOR. Sir, Much diversity of opinion exists in the political world, as to the utility—as well as the best method of conducting— “agitation.” I trust, however, that few persons will venture to question, much less deny, the value and importance of agitation in the perfecting of many useful arts and manufactures; but for some most ingenious applications of this principle, I fancy I should hardly have obtained the paper whereon to write this communication, nor the little steel instrument with which it is penned. Now without the slightest wish to interfere with, or to rival Dan. O'Connell, Esq., M.P., the most celebrated agitator of the day— yet, have I, like him, been endeavouring to introduce “an improved system of agitation.” The accompanying camera-lucida sketch, represents a “mechanical agitator,” or “shaking machine,” which I de
signed between two and three months since, for a steel pen manufacturer. The action of the machine has been much admired, and it has been applied to some other useful purposes, besides that for which it was originally intended. In the manufacture of steel pens, there is always a slight bur raised on the edges of the metal, by the cutting-out process; in the subsequent operations of annealing, hardening, tempering, &c., the surface becomes scaly and discoloured, all which defects are very conveniently removed by shaking the pens together in large quantities; the effect being assisted by the presence of some abraiding substances, as sand, ashes, sawdust, &c. The old method of accomplishing this object was, by placing the pens and the polishing materials in a bag, and shaking them for an hour or two ; this, though a tolerably efficient, was nevertheless a very tedious operation, and it was soon superseded by a metallic cylinder or barrel, mounted upon two horizontal guides, which it was made to traverse backward and forward by means of a crank. In this machine, however, the motion of the pens was too rapid, and they struck against the alternate ends of the cylinder with great violence. An improvement upon this rude apparatus consisted in supporting the cylinder itself upon two cranks, which caused it to take an oval path, by which means the pens were turned over and over at each revolution. The extreme difficulty, however, of getting two cranks so accurately made as to work smoothly and evenly together, induced me to adopt the following method of obtaining the same beneficial results in a more simple manner. In the accompanying drawing AA represents a cast iron frame; B, is the cylinder (of tin plate) for holding the pens, &c., furnished with an opening at the top, closed by a screwed cap. Two iron rings, one at either end of the cylinder, terminate on the under side in square eyes, through which the bar C is inserted; this bar is prolonged to d, where it is connected with a crank, f, on the pulley-shaft, e. The bar C is pivoted on the top of a forked shaft or inverted pendulum, g, which moves upon two centres at the lower part of the frame, h; I is the driving wheel, a belt from which passes round the pulley, e, and gives