Railroads.-But two improvements in railroads have been patented this year. One of them is for a device to prevent cattle from getting upon the road at the crossings, and is similar to other devices already in use. The other is for a method of preventing cars from running off the track in consequence of misplacing the switch. For the accomplishment of this object, frogs are used having guards or grinders on their outsides, and double inclined planes up and down, by which the wheels are guided to the right track. Considerable importance seems to be attached to this invention, and it will probably answer a valuable purpose. Bridges.—Six patents have been granted this year for improvements in bridges, and some of them are of considerable importance. It is well known that by long use and repeated strains the various parts of a truss bridge are loosened and weakened, and the bridge becomes unsafe. But, although the parts may be unable to sustain the kind of strain to which they have long been subject, they are still capable of resisting other strains; and if, therefore, the structure can be so modified that the parts will perform other duties than those they have been accustomed to, the bridge may again be rendered strong. For example, a tension rod or brace, which has been weakened as such, may be perfectly relied on as a thrust brace. Two or three patents have been granted this year for different modes of carrying out this principle. The bridges are so constructed that by a double system of nuts upon the rods ordinarily used in truss bridges, all the parts which have been subjected to tension are made subject to thrust, and the thrust ties are subjected to tension; or the change, if desired, may be partial. It will readily be perceived that a bridge possessing this versatile character, which allows the parts thus to relieve each other, will be much more durable than one of the ordinary construction. Letters patent have been granted for an improvement in the mode of bracing bridges, and of enabling them to resist lateral as well as vertical pressure. As the character of the improvements is clearly set forth in the patent, I refer to the following extract for their description: “In the construction of arch bridges, with diagonal braces between the under and upper arch pieces, the practice has heretofore been to abut the braces against the posts and arch-pieces at the junction of the two; so that the two braces, on opposite sides of each post, apply all the strain to the arch-piece at one point. This necessarily tends to break it at this point, and does not transser the strain from one part of the arch to other parts—a result so important in a good bridge. “The object of the first part of my invention is to arrange the diagonal braces between the lower and upper arch pieces, or arch-piece and its chord, and at a sufficient distance within the posts and vertical connecting rods, as to make that portion of the arch-piece perform the function of a lever; the post or connecting rod being the fulcrum, and thus to transfer the strain applied to any part of the arch from one diagonal brace to another, throughout the series, and in this way give to the arch-truss the greatest amount of stiffness due to the amount of timber employed. “It is also well known that bridges are exposed to much lateral strain from wind, tending to force the arch trusses over out of plumb; and as an arch loses much of its strength when out of plumb, it has become a matter of great importance to perfect a bridge against such tendencies. The second part of my invention consists in making the middle arch

truss of the bridge in two parts, inclined in opposite directions, connected together at top and separated at bottom, so that they resist the action of the wind in opposite directions.”

Letters patent have been granted for an improvement in anchoring suspension chains for bridges. A platform of timber is placed at the bottom, and the pier is built upon it. The anchor is placed under this platform, and between it and the platform another platform is placed, whose planks are at right-angles to those of the first. The planks of the first have their length in the direction of the bridge. The chain passes up from the anchor through the pier. With this arrangement it will be perceived that . any strain which would disturb the anchor must move the whole pier. This mode of anchoring appears at once simple and safe.

I will here close my remarks upon improvements in civil engineering. Those remaining in this class are not such as require particular illustration.

HYDRAULICS AND PNEU MATICS.

Upwards of thirty patents have been granted this year for improvements in machinery belonging to this class, and a much greater number of applications have been rejected. When it is recollected that hydraulic and pneumatic apparatus, in almost every branch, has been in use for thousands of years, and that improvements have been progressing from century to century, it is truly astonishing that at this late period, and in a single year, so many new and useful combinations have been brought to light. The various departments of this class, in which improvements have been made, will appear as I proceed hastily to review them. Filters and stop-cocks.-Nine patents under these heads have been granted this year. I have placed them together, because most of these patents are for combinations of the two. Filters have been used from the earliest periods, and many varieties of form and purifying substance. One of the inconveniences incident to them arises from their becoming foul, and the difficulty of cleaning. To facilitate cleaning, one of the patentees makes his filter a comparatively small fixture, either end of which can at pleasure be screwed to the pipe or cock from which the water is obtained. A filtering substance is placed within the case of the filter, and the water from the pipe, being obliged to pass through it, is purified. When the filter becomes foul it is taken off and inverted, and the first water which passes through will cleanse it, and immediately after pure water will be received from it. When it again becomes foul it is simply to be reinverted. Various materials have been used as a filtering medium; and one, which is familiarly known, is sponge, more or less compressed. One of the patentees uses sponge compressed to such a degree that the impurities of the water cannot penetrate at all, alleging that when thus compressed the water is easily forced through, and that all the impurities will remain upon the surface of the filtering medium, and will easily and immediately be removed by inverting the filter and passing the water through it. Several of the patentees place the filter in the core of the stop-cock. With this simple arrangement, when the core is properly turned, the water will issue from the stop-cock already filtered. It was soon, however, perceived that the impurities would collect in large quantities behind the core, and could not be discharged without removing the apparatus. This

circumstance led to several ingenious modifications of the filtering cock, all having reference to cleansing. One of the patentees made an opening in the core below the filter, which, when the core was turned into a certain position, allowed the water to escape independent of the filter, carrying all the impurities with it. The filter itself can be cleansed by simply reversing the core. Another of the patentees, instead of using the core, makes an inclined partition in the tube, with an opening in the tube on each side of it, and places the filter around the cock in such a manner that the water will pass into it through one of the above-mentioned openings, and after passing round through the filter, will enter the other opening, and be discharged from the cock in the ordinary way, in a pure state. If the filter be turned around, the direction of the water through it will be changed, and the impurities will be carried off and the filter cleansed, and can operate in that position of the parts until cleansing is again required. In a third position of the external filter the water is entirely stopped off. Other patents have been granted for devices intended to accomplish the same object; but they are similar to one or the other of those already noticed. Letters patent have been granted for two devices to be used in the pipes of hydrants, which operate under great pressure to prevent the bursting of pipes, and other evils occurring with the “water ram.” If a valve under great pressure of water is suddenly closed, the momentum of the water thus instantaneously stopped frequently occasions great mischief; and many devices have been resorted to for its prevention. One of the patentees above mentioned holds the valve down directly against the pressure of the water by a stróng spring, so that if the valve is too suddenly closed the spring will slightly yield to the ram until the water becomes quiet. The other uses two valve-seats and two valves upon the same stem. The first valve is perforated in several places to allow a partial passage of the water, and slides a limited distance on the stem. Immediately beyond each valve-seat there is a swell in the tube to allow the water to pass when the valves are forced from their seats against the pressure of the water. When the valves are opened, the water has free egress; and when suddenly closed, the perforated valve reaches its seat first by sliding on. the stem, and partially shuts off the water from the other valve and breaks the shock. While upon the subject of the water-ram, it is proper to remark that letters patent have been granted for an improvement in machinery, patented in 1845, for applying the water-ram to the raising of water. It consists simply in a device for giving greater certainty to the action of the parts previously used, and would not be understood without drawings and reference to the original apparatus.

Water-wheels.—Among many unsuccessful attempts, several real im-

provements have this year been made in water-wheels, which I hasten, to notice. Letters patent have been granted for an improved wheel, which is intended to work upon a vertical shaft, and which receives the water upon it entirely around the hub. After the water reaches the wheel it is received into openings or tubes, extending a considerable distance around the wheel. The bottoms of these tubes incline downwards, and the vertical sides approach each other to such a degree that the areas of the cross

sections of the tube are every where equal ; and the water is finally discharged tangentially, in a comparatively thin vertical sheet, immediately outside of the wheel. f Another patent has been granted for a wheel very similar to the foregoing, involving much of the same principle, but varying in some of its details. All the patents which have been granted this year for improvements in water-wheels are for such as differ but little from those in former use; and I shall notice but one other of them. Horizontal wheels have already been used with several shutes, and the wheels so constructed that when heavily loaded the water would be discharged on the interior of the wheel, and operate partially by reaction; and when lightly loaded the water would be discharged principally at the outside of the wheel. The water from each shute should of course be discharged from the wheel, when moving at high speed, before the same buckets receive the water from the second shute. Heretofore no considerable space has been prepared for the escape of the water, except under the wheel; and when the speed is very high, gravity is insufficient for the escape of all the water; but considerable quantities are carried around and interfere with the action of the succeeding shute. To remedy this evil, the wheel is placed between three or more flumes, arranged in a triangle, square, &c.; each flume has a shute, and at the angles of the combined flume there is sufficient space to discharge the water tangentially from the wheel; which is the only way to make the discharge perfect. Raising water.—Nine patents have been granted this year for improvements in pumps for raising water; but so much has heretofore been developed upon the same subject, that few present striking features of noweity. Most of them are for slight modifications of other well known pumps; and often for differences, rather than improvements. There is one improvement in pistons, which I think deserves particular notice. It is well-known that most of the injury which is done by the piston, or to which it is subject, arises from friction; and the invention alluded to, is intended to obviate these inconveniences, and is applicable to steam engines, &c., as well as pumps. It will be fully understood by reference to the following extract from the patent: “Pistons for pumps, engines, &c., which have heretofore been made to slide in a cylindrical or other formed casing, or worked with a hinged or loose flap, like a bellows, require much power to evercome the friction of the packing, whether made of metal, hemp, or other elastic substance, or to overcome the rigidity of the substances employed to connect the flap. When metallic packing is employed, the rubbing parts have to be made with great care and accuracy, and still give much friction; and consequently wear very rapidly, and require frequent adjustment, and cannot be advantageously employed with fluids containing earthy matter. With other kinds of packing, the wear is not only very rapid, but, to prevent leakage, must be made very tight, at the expense of power; and yet, when exposed for any length of time without, moisture, it is liable to leak. And, finally, the bellows flap piston, which avoids the friction of the packed piston, is found in practice to be more objectionable than the others, on account of the rigidity of the substances employed to form the connexion, and its liability to crack and break, particularly when exposed for any length of time

without moisture. In consequence of the magnitude of these evils, many unsuccessful attempts have been made to remove them. My improve. ment, it is confidently believed, will effectually remove them. It consists in substituting for the metallic or other packing, and the hinged flap, the rolling of metallic or other hard substances on each other, by making the piston of three, four, or more triangular parts, turning on rounded edges along the outer face of the triangles, the other faces being made in the form of segments of cones, and rolling on each other when moved together in the same direction, all the segments being jointed to one piston or connecting rod. The effect of their vibration will be similar to the working of the flap of a bellows.” Patents have been granted for fire engines, wind-mills, &c., which I do not deem it here necessary to describe. Letters patent have also been granted for an improved bargmeter, which appears to be of great importance in consequence of its exemption from those liabilities to injury, and even destruction, which render those in common use so objectionable. It consists simply of a cup, with a disk placed over it, air-tight, and the air exhausted from the interior. The disk, which is of sheet metal, is made waving in concentric circles, and can therefore yield as the pressure of the atmosphere increases; and by a very simple device the yielding of the disk operates a hand upon the dial or register. Those acquainted with the subject will easily understand the instrument from the foregoing remarks. It is carried with perfect ease, and is as little liable to accident as an ordinary pocket compass. No further remarks appear necessary, upon developments made at this office, in connexion with the subject of hydraulics and pneumatics.

MILLS AND MECHANICAL MOVEMENTS.

About twenty patents have been granted this year for improvements in machinery belonging to this class, some of which deserve notice, though many of them do not possess those prominent characterising features which would render a description of them useful in this place, Flouring apparatus.--It is well known to millers that the exterior coating of kernels of grain are apt to be too dry for grinding, so that when the grain is crushed between the stones, the hull, being very brittle, is ground fine, and mingles with the flour, and is with difficulty separated. on account of its fineness. To obviate this, an improvement has been made and patented this year. The wheat is subjected, as it is passing to the stone, to a jet of steam"which moistens and toughens the hulls in such a manner that they come off in flakes, and are afterwards easily separated, in the bolting apparatus, from the flour. There is one other patent for improvements in flouring mills, whose apparent commanding importance entitles it to particular notice; and if the patentee is correct in his theory, which is said to have been thoroughly tested in Europe, an important revolution in flouring establishments throughout the world must speedily take place. ... Whenever attempts have been made to drive the mill-stone at very high speed, for the purpose of effecting a rapid production of flour; the heat generated by friction has burnt and injured the flour. This evil has been of so serious a character as to limit the velocity of the stones. Various attempts have been made to surmount this obstacle, some of which have