responding divisions p, p, p, and r, r, r, of the keel, and the points where the lines intersect show the form of water-line required. The form thus attained, it will be observed, is very sharp both fore and aft, though the after part, or run, being shorter, is necessarily more full than the entrance of the vessel. This form is much opposed to the ordinary practice, inasmuch as the line is hollowed out, or partly concave, instead of being of the convex form, or full bow, which old ship-builders so much admire.

Having thus described the form of the light-water line, Mr. Russell promised to give the view he entertained of the principle on which the superiority of its construction depended; in this particular, however, he failed to make himself very clearly understood. He first alluded to the notions entertained of the manner in which the water is displaced by the motion of a vessel. It is commonly supposed, by ship-builders, that the water passes round the vessel; some imagine that the fluid is rolled under it; whilst, according to the French philosophers, the impact of water obeys the same laws as the impact of solid bodies, and the water is reflected from the bow at an angle equal to the angle of incidence. From the latter assumption they deduced that a round full bow is best adapted to meet with least resistance. It had been proved, however, in the course of these experiments, that the particles of water displaced by the bow of a vessel move into new places, that peculiar motions are given to them, and that they never return to their former positions. The motion of displacement, also, was found to be not confined to the vicinity of the vessel, but to have an extensive effect in a region anterior to the bow, and extending to a considerable distance on each side; and some time before the bow approaches a particle of water, the fluid has commenced moving. Viewing the sea as composed of innumerable verticle columns of water, the effect of the approach of a vessel is to produce greater pressure on one side of such columns than on the other, and water being, practically speaking, incompressible, the particles pressed against can move only in a vertical direction, and thus a heaping up of fluid is produced before the how of the vessel, sometimes ranging as far as half its length. The next object the committee had in view was to examine the direction of the motion of the particles of water displaced by a vessel. It was found that when the form was that of least resistance, the motions of the particles of water were in semicircles; and that they deviated from that curve when the form departed from that of least resistance. It was also determined, that the replacement of the water as a vessel moved forward, takes place entirely from below. The result, therefore, to be attained, as appeared from these experiments, was to ascertain the form of the solid of least resistance, which would communicate these motions to the particles of water. In experiments on the forms of waves, conducted also at the expense of the British Association, it had been ascertained that the motion of water itself is that which the committee had endeavored to give to the water when ships pass through it. Thus it happened, that the form best adapted for least resistance in smooth water, being itself the form of the waves of the sea, the vessel of that shape moved through the sea with the

least motion and the least resistance. The consequence was, that in the course of these experiments it was found that a vessel built in the form of least resistance in smooth water, instead of being, as was formerly supposed, likely to be wet and uneasy in a rough sea, in fact passed through the waves without doing more than modifying their motion, and that in proportion as ships approach to the form of least resistance, they were dry, easy, and good steering boats. The concluding experiments were made on ships of 2000 tons, differently formed, and the same law which was found to prevail in smaller vessels was also followed in the large ships and in the roughest seas.

We have endeavored on the foregoing report, to give as intelligible an account of the deductions from the experiments on the form of ships as could be collected from Mr. Russell's exposition. It is evident, however, that there are many points of importance not sufliciently elucidated; and though the principle on which the advantages claimed for the wave form is attempted to be established as regards easiness of motion in a rough sea, the reason why that form is the one of least resistance in smooth water, is by no means clear.

It is a very difficult, and perhaps an impossible task to extract the pith from a voluminous mass of papers, calculations and drawings adapted to differing circumstances, so as to present, in a comparatively small compass, a satisfactory view of the whole; nevertheless, we wish to arrive at some fixed laws, and the principles on which they are founded. It appears that in all the experiments the object aimed at was to ascertain the form of least resistance in cutting through the water, and that no attention was bestowed on the form best adapted to cause the vessel to glide over the head-wave. The experiments, however, which were made a few years since on the Scotch canals with passenger boats, in which we believe Mr. Russell himself took part, show that the head-wave may be prevented by the boat being raised in the water by the oblique impact of its bow with the fluid. Civ. Eng. and Arch. Jour.

Mechanics, Physics, and Chemistry.

Patent Case.-Winans vs. The Boston and Providence R. R. Co. We are particularly indebted to B. R. Nichols, Esq., of Boston, Counsellor at Law, for furnishing the following synopsis of a recent patent case, in which his Honor Judge Story decided some points of interest to inventors and patentees in general.-COм. PUB.

An action in favor of Ross Winans against the Boston and Providence Rail Road Corporation was tried in the U. S. Circuit Court, before the Hon. Judge Story, at Boston, in November last, for a violation of a patent granted to Mr. Winans on the 20th October, 1831, "for an improvement in the construction of the axles, or bearings, of rail way or other wheeled carriages."

In the specification annexed to his patent, he states that he has invented an improvement in the construction of the axles, or bearings, of rail way or other wheeled carriages, in which, instead of forming the bearing under the body of the carriage and within the naves or

hubs of the wheels, there to sustain the weight of the load, he extends the axles out at each end, projecting beyond the naves to such a length as shall enable him to form them into gudgeons-the length and diameter of these gudgeons he regulates according to the load they are intended to sustain, and to other circumstances. In all cases, however, the value of his invention depends upon the gudgeons having their diameters as small as due attention to the strength required will allow. He then states various advantages in this mode of constructing axles and gudgeons, and that this improvement was exhibited by him in an experimental rail way in 1827, and put into practical operation under his direction on the Baltimore and Ohio, and Liverpool and Manchester rail ways, in the early part of 1829, in connexion with friction wheels, for which friction wheels a patent was granted him in October, 1828. That these gudgeons were exhibited by him in England in 1829, and were adopted there without his deriving any advantage therefrom, as by the laws of that country, he could not secure the invention by patent, after having publicly exhibited it.

He then states, that the object of the invention, and a practical demonstration of its utility having been shown, its application and adaptation to the different rail road carriages, burthen wagons, locomotive engines, &c., and to the different bearing boxes that may be preferred for different purposes, (either revolving or common,) will be evident and easy to any person acquainted with the building of rail way carriages. But to render it still more so, the following general directions and proportions are given, which he thinks will be found to be a near approximation to what will be required in practice. He then states the general size of the axles and gudgeons which he would recommend for a given weight of load-and that the axles extend through and beyond the naves of the wheels on each side far enough to go under and receive the side frame of the load-bed-on the four gudgeons thus formed, the carriage body rests by means of any hard metal bearings attached to the side pieces, which side pieces are so framed with the cross pieces of the bed as to go on the outside of the wheels, either over or under the gudgeons as convenience may require. The friction occasioned by the tendency to a lateral movement of the gudgeon is limited by causing the end cover of the bearing to meet the end of the gudgeon as near to the centre of action as possible. When the revolving box is used, this end is attained by forming the end perfectly square, and when the common box is used, by forming the end of the gudgeons convex or rounding. In consequence of the small extent of bearing surface, the bearing box should be made as hard as the use of the most favorable materials for that purpose would permit. He then speaks of oiling the gudgeons and of preventing the oil working out, by turning one or two small rings or grooves on a portion of the axle between the gudgeon and the nave of the wheel. He then states that he does not intend to claim all merely projecting axles beyond, or external to, the wheels-and alludes to several of a different construction, either having a single wheel, or having a separate axle for each wheel, or one made subsequent to his invention for a temporary object, and not effecting the

like purpose, and that his invention is sufficiently distinguished from others by the new and useful effect produced in manner aforesaid. He then sums up his claim as follows:

"I therefore declare, that the improvement or improvements, above explained and described, in diminishing the resistance to motion in wheeled carriages to be used on rail ways, which I claim as my own invention, is the extending the axles each way outside of a pair or pairs of wheels, far enough to form external gudgeons to receive the bearing box of the load body, and diminished as aforesaid, with a view to lessen the resistance of friction, as small as its situation, with the use of the most favorable metal for wear, will permit. Thus conveniently increasing the leverage of the wheels, without impairing their effective strength and durability."

The defendants pleaded the general issue, and filed a specification of the various grounds of defence on which they relied-and among others, that the invention claimed was not new, but was, before the supposed discovery thereof, described in various printed publications, especially in Edgeworth on roads and carriages, where he describes the Irish car, with outside bearings, the axle turning with the wheels. The plaintiff admitted that carriages with out side bearings, were in use before his invention, but he contended that by the specification annexed to his patent, he claimed simply the application of such outside bearings with diminished journals to rail road carriages.

The Court, however, decided, first, that he did not claim the application merely to rail road carriages, as appears by the title of his patent and the first clause in his specification, and secondly, that if he claimed merely such application, it could not be allowed, for it has repeatedly been decided that the application of an old invention to a new purpose, without any new contrivance or machinery, was no ground for a patent; and that if a patent, under these circumstances, could be sustained at all, it must be for the new mode of construction and new machinery by which the old invention was so appliedwhich new construction and machinery must be particularly specified. Here the plaintiff claimed generally the extending the axles each way outside of a pair or pairs of wheels far enough to form external gudgeons, and diminished with a view to lessen the resistance of friction. It being admitted that such mode of constructing axles had been before used in other carriages, the mere application of the same to rail road carriages was no ground for a patent.

This point being decisive of the cause, the other points of defence, viz: that the plaintiff was not the original inventor even as applied to rail road carriages, and that if he had been, he had abandoned the same to the public, and that the same had been in use by others for more than two years prior to granting the patent, were not discussed or considered..

GLEANINGS FROM FOREIGN JOURNALS.-No. III.

On a Remarkable Photographic Process, by Sir John Herschel. -If nitrate of silver, specific gravity 1.200, be added to ferro-tartaric

acid, specific gravity 1.023, a precipitate falls, which is in great measure redissolved by a gentle heat, leaving a black sediment, which being cleared by subsidence, a liquid of a pale yellow color is obtained in which a further addition of the nitrate causes no turbidness. When the total quantity of the nitrated solution added amounts to about half the bulk of the ferro-tartaric acid, it is enough. The liquid so prepared does not alter by keeping in the dark. Spread on paper and exposed wet to the sunshine (partly shaded) for a few seconds, no impression seems to have been made, but by degrees, although withdrawn from the action of the light, it developes itself spontaneously, and at length becomes very intense. But if the paper be thoroughly dried in the dark, (in which state it is of a very pale greenish yellow color,) it possesses the singular property of receiving a dormant, or invisible picture; to produce which (if it be, for instance, an engraving that is to be copied,) from thirty seconds to a minute's exposure in the sunshine is requisite. It should not be continued too long, as not only is the ultimate effect less striking, but a picture begins to be visibly produced, which darkens spontaneously after it is withdrawn. But if the exposure be discontinued before this effect comes on, an invisible impression is the result, to develope which all that is necessary is to breathe upon it, when it immediately appears, and very speedily acquires an extraordinary intensity and sharpness as if by magic. Instead of the breath, it may be subject to the regulated action of aqueous vapor, by laying it in a blotting paper book, of which some of the outer leaves on both sides have been damped by holding it over warm water.

Barometric Compensating Pendulum-In 1825, Dr. Robinson of Armagh, by comparing the rate of the transit clock of his observatory with the indications of the barometer, found that there was an effect decidedly due to the varying density of the air. To remedy this he attached a barometer tube to the pendulum, so adjusted as to increase the time of vibration, by removing a cylinder of mercury further from the axis of the pendulum, as much as the diminished density of the air would have increased the same time. A fall of 1.6 of an inch in the barometer last year, produced a perceptible change of arc in the pendulum.

Classification of Waves.-Mr. Scott Russell classifies waves into four orders first, the wave of translation, solitary in its character; second, waves of oscillation; third, capillary waves; fourth, corpuscular waves; all these latter are gregarious. The velocity in the first order of waves is dependent on their height and the depth of the fluid; each particle of water describes a semi-circle or a semi-ellipse, and then comes to rest, all the particles throughout the depth suffer the same amount of horizontal translation. The velocity in the second order depends upon the length of the wave alone; the particles of water describe curves returning into themselves, there is no permanent translation and the effects extend to moderate depths only beneath the surface.