The report to the Secretary of the Navy, Mr. Henshaw, dated 5th February, 1844, by Captain Stockton, goes to show, that the Princeton was considered a perfect ship, in all respects, for he says:

"Constructed on the most approved principles of naval architecture, she is believed to be at least equal to any ship of her class, with her sails. She has, also, an auxiliary steam power, and can make greater speed than any sea-going steamer, or other vessel heretofore built."

"The advantages of the Princeton over both sailing vessels and steamers propelled in the usual way, are great and obvious. She can go in and out of port at pleasure, without regard to the force and direction of the wind and tide, or the thickness of the ice. She can ride with safety with her anchors in the most open roadstead, and may lie-to in the most severe gale with perfect safety. She can not only save herself, but will be able to tow a squadron from the dangers of a lee shore, using ordinarily the power of the wind, and reserving her fuel for emergencies."

I might quote much more from the report of Captain Stockton, to show that the Princeton was considered perfect at the time the report was made. If the change was made for the purpose of testing two rival inventions, it is pretty clear to me that the object has been attained, so far as to show, at least, that the "Stevens scull" is not superior to the "Ericsson propeller." I am informed that the 5.6 revolutions of the scull required an additional force of full 70 horses over and above that required to turn the propeller. If this be true, I cannot make out the gain claimed.

What has the scull done then? To which I am answered: That with the same pressure of steam on the boiler, but with a greatly increased consumption of said steam, it has propelled the ship faster, the means being increased rather more than in proportion to the effect produced.

The rate at which the Princeton was reported to have steamed in the Delaware, with "Ericsson's propeller," by ground log, was 13 statute miles, with 36'6 revolutions.

The table of captain Stockton shows that with 30 revolutions she made 11.04 miles ; and with the scull, making 35.6 revolutions, she made within a fraction of twelve miles per hour, or six miles in 29 m. 47 sec.

Now a comparison of the rates at which the two powers moved, and the rate attained in the Delaware, and at Norfolk, would show as follows:

As 30: 36·6=11·04 : 13·4 proving incontestably that the rate obtained in the Dela

ware by the "Ericsson propeller depended on.

207

may be

It also proves that had the "propeller " moved as fast as the "screw," it would have propelled the ship faster than the latter.

Besides the difference stated, namely, the four miles made with the wind, and two against it; the difference of pressure throughout, in one engine of a force equal to 1 lb. pressure on the boiler, and the possibility of the ship's bottom having been in better order after being in dock, I am informed that one of the plates of the propeller had been so much bent by striking a log or stake in New York harbour, that it became necessary to cut it partially away, and that one or more of the other five plates were more or less bent out of angle. I am also informed that this damage was not rectified before the final trial of the propeller.

Finally, I would call the attention of those who feel any interest in the matter, to the fact, (derived from Captain Stockton's own report,) that the engines were worked with the scull as fast as they were ever worked before; yet the former maximum speed was not attained within nearly 1 miles per hour. Thus, to attain the former maximum speed, if not impossible, will require a speed of the engines for which they were not constructed, and which they cannot safely bear for any continued period. NAUTICUS.

RECENT AMERICAN PATENTS.

[Selected and abridged from Mr. Keller's Reports in the Franklin Journal.]

AN IMPROVEMENT IN THE COUPLING AND STUFFING BOX FOR SHAFTS, SPECIALLY INTENDED FOR SUBMERGED PROPELLERS FOR SHIPS. R. F. Loper.-The outer tube of the stuffing-box, instead of being permanent, is tapped into a metallic casing surrounding it so as to admit of screwing it over the lapped or other joint of the shaft, so that when this tube is drawn in, the two shafts can be separated, and, if desired, the propeller drawn up out of the water, and when screwed out, passes over and prevents the two shafts from being separated.

Claim." Having thus fully described my improvements, what I claim therein, and what I desire to secure by letters patent, is the before-described mode of employing the cylindrical tube for the double purpose of a coupling-box and stuffing-box, by combining it with the coupling shaft and with the other portions of the stuffing-box; by which arrangement much room is saved, and great simplicity attained-all as herein described." A METHOD OF DIRECTING THE COURSE OF AEROSTATS OR BALLOONS. Muzio

208

Muzzio. To run fourteen years from the 12th of May, 1842, the date of Letters Patent granted in France.

Claim." Having thus fully described the manner in which I construct and operate my balloon, or aërostat, I will remark, that I am aware that inclined planes have been applied to aërial machines for the purpose of enabling them to ascend by the resistance of the air; it having been attempted to propel such machines by flapping instruments called wings, by revolving screws, by paddles, and by other similar means. I am also aware that machines thus attempted to be propelled have been furnished with jointed inclined planes, for the purpose of guiding them in the manner of the tail of a bird; it is to be understood, therefore, that I do not claim as of my invention the mere application of inclined planes for the decomposition or resolution of the ascending and descending forces. But what I do claim as my invention, and desire to secure by letters patent, is the combination of inclined planes, substantially as herein described, with an aërial machine, or balloon, which is made to ascend and descend by a change in its specific gravity, as set forth; the ascending and descending forces decomposed or neutralized, and* resolved into a horizontal one, or rather into a progressive line more or less inclined to the horizon, by the aid of atmospheric resistance; whereby the whole machine is impelled forward, and the direction changed at pleasure, by altering the inclination of the planes; the same being effected substantially as herein described. But it is to be distinctly understood that I do not limit my claim to the number or to the form of the inclined planes, or to the particular manner of operating them, or to the manner of obtaining an ascending and descending force, so long as the same is effected by a change of a specific gravity of the balloon, which, it will be evident, may be effected by the generation of hydrogen, as well as by its discharge."

IMPROVEMENTS IN THE METHOD OF REGULATING THE DRAUGHT OF STOVES AND FURNACES. Joseph Saxton and George Elliot. In this stove all the joints are made with the view to have them all air-tight, as near as practicable, by luting or other known means. The fuel is introduced through a hole in the top covered by a disk, having a flanch around it, and dipping into sand contained in an annular trough, or cup. The ash-box, which is circular, is also provided with an annular cup containing sand, which, when borne up, receives a rim, or ring, sur

rounding the opening of the grate, and for the purpose of bearing up the ash-box it rests on three circular inclined planes, which force it up when turned partially round; when let down it can be drawn out in the usual manner.

The air for feeding the fire is admitted through a small hole governed by a valve connected with a compensation bar attached to the stove. This compensation bar is composed of two metals of different expansibility, the most sensitive being placed next the stove, and the connexion between the bar and the valve is by means of a regulating screw; when the temperature is too great the bar expands, and permits the valve to close and cut off the supply of air, and when it contracts the valve is opened to admit air.

A MACHINE FOR MINCING BLUBBER ON BOARD OF SHIPS ENGAGED IN THE WHALE FISHERY. George Kilburn and John J.Kilburn.-This machine consists of a wheel, one face of which is at right angles with the shaft, and the other bevelled towards the periphery. To the straight face of this wheel, a curved knife is attached, which extends from a little beyond the periphery to about midway between the periphery and the centre, and back of this knife the wheel is pierced with a bevelled opening. The blubber is fed up to the cutter in a hopper, the bottom of which is a little below the range of the outer extremity of the knife, so that each slice that is cut, is not entirely severed from the mass.

THE ATMOSPHERIC RAILWAY.-R. w.'s

PLAN.

Sir,-Perhaps your correspondent, R.W., will be so kind as to give a minute description of the form and mode of action of the revolving double valves to which he alludes in your last Number. I can readily understand how a piston may open a valve at the end of, say a three-mile length of tubing, but cannot comprehend how a piston can possibly open and close the valves placed as R. W. proposes. If he can satisfy us in this respect, we shall have cause to tender him our best thanks, as undoubtedly in that case it must be a very ingenious contrivance. I am, Sir, your obedient servant, FREDERICK LIPSCOMBE.

93, Regent-street.

INTENDING PATENTEES may be supplied gratis with Instructions, by application (post-paid) to Messrs. Robertson and Co. 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS.

66

cams," actuated by the same very small steam-engine which is required to feed the boilers with water.

It is proposed to condense the steam, so that the condensing water shall flow off at 70° Fahrenheit; at this temperature such quantity of it as is required is withdrawn by the feed pumps from the Iwell at the lower end of the condenser syphon, and pumped into the hot-water tube in the boiler flue before spoken of. This constitutes the whole apparatus, its operation is as follows:

Steam being up in the boilers, a little is blown off into the condenser, and the stop-valve shut; the condensing water is admitted, and a very slight vacuum is produced in the condenser. This is requisite to cause the steam from the first vacuum vessel to enter the condenser rapidly, when permitted. The steam valve is now opened to one vacuum vessel, say the left-hand one, the other two valves, viz., the condenser and railway valves, being shut. The air is expelled from it by the snifting valves, and as soon as steam "blows through," the valve from the boiler is shut, and the condenser valve opened; the contents of the vacuum vessel now rush into the condenser, and are condensed. The valve between the vacuum vessel and condenser is now shut, and that between the former and railway tube opened, when air from the latter rushes into the partial vacuum of the vessel.

The moment the steam valve was shut to the left-hand vessel, it was opened to the right-hand one, which in the same way was filled, and by a precisely similar set of operations a partial vacuum was formed in it, and communication made between it and the railway tube just subsequent to the moment when communiIcation was closed between it and the former vessel, and so on alternately, each

199.)

vessel being filled with steam; this condensed, a vacuum produced, and air admitted therein from the railway tube until in equilibrium.

These actions recur at regular intervals, and the cams moving with a uniform motion, are so arranged as to open and close the several valves at the proper times.

These times and the general working of the machine, which is much more simple than it seems in words, are best seen by inspecting the following diagram or expression in signs of the whole motions. (For which see opposite page.)

It will thus be observed that each of the vacuum vessels is alternately engaged in exhausting the railway tube and in forming its own vacuum. The valves are at the first moment moved by hand, and afterwards uniformly by the engine, which is worked by the same steam boilers as are employed in the apparatus at large.

We have next to consider the proportions of the various parts of the apparatus. Let us suppose, as applicable to a length of six miles of 15-inch pipe. The capacity of the tube is

The capacity of the condenser need not be more than one half that of either condensing vessel, for such a proportion has been found to give sufficiently rapid condensation in large steam-engines, and the same must hold here. Hence the condenser will be one cylinder of 10 feet diameter, and 124 feet long.

The dimensions of the boilers are dependent upon the supply of steam demanded per minute.

We shall presently see that a sufficient vacuum for starting will be produced in a 15-inch pipe of six miles long, by three