the expressions for power, on the above stated hypothesis, the slight discrepancies being occasioned by small errors of observation, particularly as the fraction of a stroke was estimated by the eye.

Another conclusion to be drawn from these diagrams is that, under the same circumstances of vessel and weather, the number of double strokes made by the piston in any given time is as the square root of the pressure on it. Taking column A of double strokes from the above table, and the square roots of column C of pressures, we have:—

The law, that the number of double strokes made by the piston in any given time is as the square root of the pressure on it, might have been deduced from the previous hypothesis, that the power required to propel a vessel is as the cube of the vessel's speed; and that the vessel's speed is directly as the number of double strokes of the piston in any given time. Because, in the expression for power, the element velocity is represented by the number of double strokes of the piston, and for a double speed this element is only doubled; but for a double speed the power must be cubed; therefore the element pressure must be squared in order that the product of the two elements shall be a cube. Hence, for different speeds we find the pressure must be proportional to the square of the speeds, or the speeds proportional to the square roots of the pressure.

Railway Passenger Assurance Company.*

The Directors of the Edinburgh and Glasgow Railway Company have resolved that, in future, they will not give any allowance or compensation to their servants in cases of death or injury arising from accidents, "as they have an opportunity, by the payment of a small premium periodically, to insure an adequate sum in case of injury, and to provide for their families in the event of death." In consequence of this resolution, the manager, Mr. Latham, has issued a general order, urging upon enginedrivers, firemen, and guards, the necessity of availing themselves, forthwith, of the benefits held forth by the Railway Passenger Assurance Co.Glasgow Daily Mail.

The Way to Make Engineers.†

An excellent and speedy mode of making engineers has been discovered by the Maryport and Carlisle Directors. It is to take on a young man at 12s. a week for a short time, when, as a matter of course, he will become an engineer without any other tuition or labor. Confound Stephenson

* From the London Railway Journal, for November, 1850. † Ibid.

and other engineers, what right have they to make the high charges they do when an ignorant fellow put upon a railway at 2s. a day becomes a railway engineer in a few weeks? "It is too bad."

We know better here on our railroads, but the above process is very much the one by which our engine drivers and steamboat engineers are manufactured. Hence our numerous and rapidly increasing explosions, and the great loss, not only of money, (as on an ill-constructed railroad,) but of life. See the article on this subject in our January number.

F.

AMERICAN PATENTS.

List of American Patents which issued from December 17, 1850, to January 7, 1851, (inclusive,) with Exemplifications by CHARLES M. KELLER, late Chief Examiner of Patents in the U. S. Patent Office.

27. For Improvements in Mills for Sawing with Circular Saws; Orlando Child, Granville, Putnam county, Illinois, December 17.

Claim. "What I claim as new in my invention, is, 1st, the springs G and G1, carrying the journal boxes g and g1, attached and arranged in the manner substantially as herein described, for the purpose of guiding the saw, but at the same time allowing a sufficient degree of end play to the spindle to admit of its accommodating itself to the lateral springing of the log.

"2d, Arranging the saw N and its spindle on the swinging frame, which is adjustable so as to bring the saw N in any required position in a line forming part of a circle round the axis of the saw D, and adjusting the said saw N either in a line with, or to the right or left of, the saw D, by means of the slot in the spring G1, through which the bolt passes, in the manner herein described, or in any manner substantially the same."

28. For Improvements in Machinery for Doubling and Twisting Silk, &c.; Joseph Conant and Lucius Dimock, Northampton, Hampshire county, Massachusetts, December 17.

Claim. "What we claim as new, is so constructing the catch-bar that all the threads or silk, either before or after being twisted, may be secured by the catchers simultaneously, by simply bringing the bar with its catchers down upon the threads, and whilst in that position, causing all the helical springs to act on the catchers at the same time, by suddenly disengaging the slide lock plate from the end of the bar, the mortises in the said plate being so formed as to allow each catch to be opened separately without the aid of the lock plate; or all to be opened simultaneously by moving said lock plate longitudinally in the manner herein set forth."

29. For an Improvement in Apparatus for Emptying Privies; Florimond Datichiry, City of New York, December 17.

"My improvements consist in the addition of a chamber or gasometer to the receiver of the apparatus for emptying vaults of privies by atmospheric pressure; the object being to allow space for the gases contained in the suction pipes and those arising from the fecal matter, without their occupying part of the receiver itself, and the gasometer being separated from the receiver and communicating with it only by a small passage, the matter (which entirely fills the receiver in consequence of the additional space provided for the gases) has but a small portion of its surface exposed to the gases, and is thus prevented from becoming mixed with them."

Claim. "What I claim as new therein, is the gasometer connected with the receiver as described, for the purpose of keeping the gases separated from the fecal matter, and pre

venting their mixture as set forth, and serving also as a reservoir for the compressed gases from which the power for expelling the contents of the receiver is obtained."

30. For an Improvement in Carriages; Edward Everett and Charles Everett, Jr., City of Washington, D. C., December 17.

Claim. "What we claim as new therein, is the joint on which the fore carriage turns, when placed in rear of the fore axle, in combination with the segment on which the end of the perch rests, substantially as described, for the purpose of allowing the carriage to be turned in a small space, without having the fore wheels to run under the body or interfering with the hind wheels."

31. For Improvements in Machinery for Cutting and Bending Sheet Metal; Joseph F. Flanders, Newburyport, Essex county, Massachusetts, December 17.

Claim. "I claim the improvement in the bending mechanism, the same consisting in the combination. of the conic or approximately conic roller or projection with the cylindric part or roller, and with the circular disks or holders, in the manner as above described, and so as, when pressed against the tin, to gradually bend it over and down upon the disk or holder, so as to enable the roller to pass over and upon the tin, and complete the bending of it down upon the periphery of the holder.

"I also claim the improvement in the construction of the gauge, whereby it is adapted to operate when the tin plate is rotated in a vertical plane, such improvement consisting in arranging its supporting journal at an inclination to the horizontal plane, and applying a weighted arm or its mechanical equivalent to the gauge as seen in the drawings, or so that the gravitating power of the weighted arm shall restore the gauge to its original and proper position under the holders, after it has been freed from the pressure of the surplus tin, or part removed by the cutters."

32. For an Improvement in Seed Planters; Joseph W. Fawkes, Bart township, Lancaster county, Pennsylvania, December 17.

"The nature and object of my invention and improvement consists in sowing grain, wheat, and oats with more constant regularity, by curved slots or apertures in the horizontal cog wheels, as arranged under the hopper, with the devices for gearing and ungearing, and the adjusting shovels."

Claim. "What I claim as my invention, is the peculiar construction of the adjustable shovels to clear the mouth of any obstructions.

"I also claim the mode and manner of sowing the grain through the slots, as herein described."

33. For Improved Expansion Gear for Horizontal Engines; Samuel H. Gilman, Cincinnati, Ohio, December 17.

"The main object of this invention is to provide for a horizontal engine, operated by puppet valves, an economical form of cut-off movement capable of adjustment to any point of the stroke, the mechanism being of such a structure as to be adjustable either while the engine is in full activity or otherwise."

Claim. "What I claim therein as new, is withdrawing the sliding tongue of the lifter of the supply valves of steam cylinders, so as to trip the valves at any desired point, by an adjustable prong which is made to slide upon the arm holding the usual fixed prong, by the action of a tappet on the rock shaft, when this adjustment is effected by means of the shackle and links within the steam chest, the shackle and links being elevated or depressed by an index arm without-side the steam chest, and the whole being arranged and operating substantially as herein described."

34. For a Machine for Making Eyelets; Lucien E. Hicks, Assignor to Wm. A. Churchill and James Stanley, Berlin, Hartford county, Connecticut, December 17. "The nature of this invention consists in so arranging and combining various mechanical elements and devices in a single machine as to facilitate the manufacture of metallic eyelets, the machine forming one eyelet complete by each revolution of the principal shaft.” Claim. "What I claim as my invention, is the sliding bolster, constructed with its two dies c and e, and aperture, in combination with the feeding tube, punches, and clearers; VOL. XXI.-THIRD SERIES.-No. 2.-FEBRUARY, 1851. 9

the whole being constructed, arranged, and operated substantially in the manner and for the purpose herein set forth."

35. For an Improvement in Grain Cradle Fingers; Joel Houghton, Ogden, Monroe county, New York, December 17.

Claim.—“What I claim as my invention, is the insertion of a metallic plate into the edge of a cradle finger by means of rivets or other fastenings, so as to keep the plate and finger permanently attached together and in their place, and thereby effectually prevent the finger from straightening or springing back when used in damp grain-prevent the grain from wearing it away, and prevent the grain from sliding endwise off the cradle before the cradler gets it round into his own swath."

36. For an Improved Sash Fastener; William H. Lazelle, Hartford, Connecticut, December 17.

"My improvement consists in using a cam secured in a slot or mortice in a plate, by means of the shaft of the knob or handle passing through holes in ears or projecting pieces on the back side of the plate, serving as a fulcrum pin; and also (by means of a lip on this fulcrum pin and a slot in one of the projections) as a fastener to prevent the cam from being turned back by any force whatever, thus locking or fastening the lower sash down with absolute safety, while the knob or handle serves to turn the cam back when it is desired to raise the sash, in the first instance, and to let it down at all times."

Claim. "What I claim as my invention, is the combination of the cam with the plate, when these are combined with the shaft and lip for turning back the cam when necessary, and locking it to fasten down the lower sash, when the whole is constructed, arranged, and combined substantially as herein described."

37. For an Improved Arrangement of Steam Engine; Richard F. Loper and John W. Nystrom, Philadelphia, Pennsylvania, December 17.

"Our invention consists in a particular arrangement of the beams, connecting rods, and crank shaft of the two cylinders of a double cylinder engine, by which the crank shaft is forced to make a complete revolution while the piston of one engine is making a single stroke, or is traveling from one end of the cylinder to the other, while at the same time the arrangement of the various parts is such that the crank to which the two connecting rods are applied cannot be placed in any position in which the power acting upon one of the connecting rods is not tending to turn it. The crank shaft of our engine, therefore, makes twice as many revolutions as that of engines of the usual construction, in which this shaft makes but one revolution for each double stroke of the piston, while at the same time this increase in speed is obtained without the employment of cog gearing, or of any similar device."

Claim. "What we claim as our invention, is the arrangement herein set forth of the beams, connecting rods, and crank of the two cylinders of a double cylinder engine."

38. For an Improved Composition for Making Cores for Casting; Edward Rees, Cincinnati, Ohio, December 17.

Claim. "What I claim therein as new, is the use of white of egg as a component in the preparation of loam for cores and other similar things intended for contact with molten metal, in the manner herein described, limiting myself to that use of white of egg, but not limiting myself to the precise proportions mentioned, while the same result is obtained by the said addition to the ingredients ordinarily used in loam for cores."

39. For an Improvement in Mills for Grinding; John Rogers, Jr., Jackson, Jackson county, Michigan, December 17.

"My improvement relates to the manner of supporting the bed stone by a universal joint upon a lever raised and lowered by a screw for raising and lowering the bed stone, the universal joint rendering the bed stone self-adjustive in relation to the runner.

"Also to the formation of an annular space between the stones and runner, in combination with a funnel-shaped space beneath the bed, for the free discharge of the meal and increase of draft.