could yield, by short posts driven into the ground or in some similar and conWhether these fences will answer a better purpose than those

venient way.
heretofore in use must be determined by experiment.

Rail Road Alarms.-One patent has been granted for a rail road alarm, but it is a re-issue of a patent granted some years since, and too well known to require description.

Letters patent have been granted for improvements in metallic roofing. The novelty of the invention is not very striking, but consists principally in so shaping the plates as at once to make a sound roof, and have each plate in such condition that it can be removed and another substituted without disturbing the other plates of the roof.

Pneumatic Rail Way.-One patent has been granted for improvements in this variety of rail way. Flexible air-tight tubes are placed along the track for the wheels of the cars to travel upon. Air is then forced into these tubes, behind the wheels, by any known means, and as the tubes expand in rear of the wheels they are caused thereby to revolve and the car progresses. The tube, the wheels, and the ways, are so adapted to each other, that the air forced into the tube will not pass the wheel.

A very important improvement in pile drivers has been patented within the year. The machine is operated by steam. The driver is connected with the piston rod of a steam engine, which rests upon the top of the pile and is properly guided in its descent. The steam pipe connecting the boiler with the cylinder is jointed so that the apparatus may ascend and descend without disturbing the connection. When the steam is let into the cylinder the piston and driver are raised and by the discharge of the steam are allowed to fall upon the top of the pile driving it downwards. These blows may be given very rapidly, and their force is much aided by the weight of the apparatus resting upon the top of the pile and descending with it.

Bridges. Three patents have been granted this year for improvements in bridges. One is for an improved mode of passing the wires or ropes for sustaining suspension bridges across the water. Another is for a system of trussing along the middle of the bridge to sustain it against vertical or lateral, pressures. The third is for a combination and some other modifications of the systems of suspension and thurst, heretofore resorted to, for sustaining bridges. The bridge seems to combine lightness, cheapness, and great practical utility, but it would be impossible in this place to give a clear description of it.

No other inventions in this class appear to require particular notice, and I will therefore pass on to the next.

LAND CONVEYANCE

Upwards of thirty patents for improvements belonging to this class have been granted within the year, some of which are of considerable importance. Wheels for Cars and Carriages.-An unusual number of improvements in wheels have come under my observation this year. Most of which are intended to obviate the difficulties which have always existed in connecting the rims of cast iron wheels with the hubs. The tread and flanches of car wheels should be chilled; and they are necessarily much thicker than the discs which connect them with the hub. These circumstances render it very difficult to accommodate the shrinkage of the various parts, in cooling, to each other, and if this is not done the wheel will crack or be weakened, in such a manner as to become useless-or if applied to use disastrous acci

dents will frequently follow. To avoid this evil the discs have been made concave, convex, and concavo-convex, and fluted in various ways. These shapes, it is easily perceived, are capable of yielding as they cool in such manner as to compensate in some degree for shrinkage, but still it has been found difficult to cast perfect wheels. Wheels having one disc, and those having two, have already been cast, but letters patent have been granted this year for a wheel with two outward and one central disc. Three discs being made and arranged as above, the plates may be made much thinner, giving the required strength, and cooling quicker, so as to avoid the conse quences of shrinkage, after the rim is chilled.

In another of the wheels patented the two ends of the hub are connected together by a convex plate which will allow the ends of the hub to approach or recede from each other in cooling and thus compensate for the inequality of shrinkage.

In another of the wheels patented the whole wheel, discs and all, are chilled with a view of avoiding unequal shrinkage altogether.

Several other patents have been granted for improvements in wheels but it is deemed unnecessary to dwell longer upon this subject.

Brakes. Two patents have been granted for valuable improvements in carriage brakes which it would be difficult to describe intelligibly, and which will therefore be passed over.

Bores for Axles.-Letters patent have been granted for an improvement in boxes for axles which allows slight vibrations of the axle in every direction, and increases the durability of the parts, at the same time rendering the motion of the cars easier.

Another improvement in boxes has been patented which consists of a kind of skeleton frame work to hold the anti-attrition metal now so generally used in boxes. The advantage of these is that wherever the soft metal is too much worn the whole can be taken out without difficulty and another frame with its soft metal immediately substituted.

Carriages. Several patents have been granted for improvements in carriages, one of which is for rendering them capable of floating over streams, marshes, &c. where they are too deep for the wheels. The parts are so arranged that wherever the water is sufficiently shallow, the burden will be borne by the wheels, and when too deep for this the whole will float.

Several patents have been granted for hanging carriage bodies. One for hanging them, so that any weight at any point upon them will depress them equally at all points. Another for hanging them upon springs and levers, so that the springs shall lie along the bottom of the carriage body; and also for supporting the ends of the spring on the axle near the hub and making it act as the bolster with the fifth wheel above it.

Letters patent have also been granted for a convenient mode of changing the pole or thills of carriages so as to adopt them to one or two horses at pleasure.

Letters patent have been granted for an improvement in pneumatic springs for carriages which cannot in this place, be fully described, but which consists principally in connecting the moving and stationary parts together by flexible media impervious to air.

Several patents have been granted for improvements in whiffle-trees and harness, intended to facilitate the disengaging of the horse from the carriage in cases of necessity. It is not deemed important to give a particular descrip

tion of them.

Letters patent have also been granted for an improvement in washers and lynch pins intended to retain the lynch pin in place.

Letters patent have been granted for improvements in the bodies of coal cars. The car body has the form of an inverted frustum of a cone which allows the bottom of it to extend nearly to the ground between the wheels; and nearly mid-way between the top and bottom of the car body, bars are placed across to relieve the bottom from the principal part of the weight of the load.

It is not thought necessary particularly to notice the remaining improvements in land conveyance.

HYDRAULICS AND PNEUMATICS.

Upwards of twenty patents have been granted within the year, for inprovements belonging to the class of hydraulics and pneumatics, very few of which can be particularly noticed. These subjects have so long exercised the ingenuity of inventors that little else appears possible, but to refine upon what has already been done. These refinements, however, important, generally differ so little from what has previously been done, that it would be impossible without drawings and descriptions more minute than can be here given to point out their patentable characteristics.

Raising Water.-Several patents have been granted for improvements in pumps and other devices for raising water, some of which may be noticed. Two of these are for the combination and arrangement of the valves and valve seats with the water-ways in such a manner, that by simply removing a small plate, the valve and seats are entirely liberated, and may be removed and replaced without difficulty.

The syphon has long been known for elevating liquids from one vessel and discharging them into another; but however high the liquid may rise in its passage from one point to the other, its has always been discharged at a point lower than that at which it was received, except in the case of the syphon ram. Letters patent have been granted within the year for improve ments in the syphon, by which a portion of the water is discharged at a point higher than that at which it is received. The machine is complicated, and cannot here be intelligibly described.

Letters patent have been granted for a portable steam pump, intended principally for pumping the water from sunken vessels. It is very compact and effective. It consists of a steam cylinder, piston, piston rod and cross head, placed between two pumps, the cross head being connected with the piston rods of the pump, and operating them. The pumps and engine are in a horizontal position, and the platform upon which they rest is hollow, and contains the valves and water-ways. This pump is too well known to render further description of it necessary.

Letters patent have also been granted for a centrifugal pump for wrecking purposes, with which it is said successful experiments have been already made.

Two patents have been granted, for improvements in the water ram, the object of which is to elevate pure water by the use of that which is impure, economizing the pure water and wasting only the impure. The two kinds of water are kept separate during the operation of the machine-in the one case by a flexible vibrating diaphragm, and in the other by a stratum of air and vertical partitions. Both machines seem calculated to answer a useful purpose

Letters patent have been granted for a hydraulic engine. It has two cylinders and pistons, and the water, in driving the engines, operates alternately on one side of each piston. This engine possesses but little novelty, and much resembles a primitive steam engine.

Letters patent have been granted for improvements in filtering stopcocks, and also for improvements in fire engines. The improvement in the fire engine has reference to stability, and a more convenient and effective application of the power.

Several patents have been granted for improvements in water wheels, most of which are slight modifications of those already in use, and some of them are complicated. No descriptions of them, therefore, which would be interesting or useful, could be given in this place, without transcending ap propriate limits; and as the same remarks apply to other improvements in this class, I will here dismiss it and hasten to the next.

MILLS, MECHANICAL MOVEMENTS, &c.

Nearly twenty patents for improvements in machinery belonging to this class have been granted within the year. Many of these "improvements" would perhaps more appropriately be denomiated changes, as they appear to promise but little utility. Some of them, however, are worthy of notice.

Grinding Mills.-One of the patents granted this year for improvements in grinding mills was noticed in my last report, having been examined in December, 1846, and although apparently an important improvement, does not require further notice.

Letters patent have been granted for a mode of elevating and depressing the runner stones of several mills at a time, so that all shall have the same adjustment by a single operation.

Letters patent have also been granted for making the drum which drives the mill spindle, at the same time a fan for cooling the stones and for blowing out any dust which may be in the grain as it drops from the hopper into the mill.

Horse Powers.-Three patents have been granted for modifications of horse powers, a correct idea of the characteristics of which cannot here be given. One of them appears to be useful, as it is simple of its kind and efficient. The other two manifest much more ingenuity than utility. Fewer attempts at improvements in horse powers seem to have been ma le during the past year than formerly.

Letters patent have been granted for improved machinery for elevating grain from vessels. The vessel, in consequence of the motion of the water, is seldom at rest, and the grain to be elevated is for other reasons at various depths. The object of the machinery in question is, by a self-acting apparatus, to compensate for the inequalities above mentioned, without interrupting the operation.

An ingenious machine for dressing mill stones has been patented this year, which, however, is too complicated to be intelligibly described in this place. The cutters are so regulated as to vary the depth and width of the different parts of the grooves in the manner required.

Letters patent have also been granted for an improvement in drivers for mill stones, so constructed and connected with the spindle and mill stone that the stone may retain its proper position, independent of the vibrating or wabbling motion of the spindle. A very perfect mode of suspending

shafts, whether for mills, water wheels, or other similar purposes, has also been patented.

Letters patent have been granted for improvements in producing a recip rocating, by a rotary motion; and two patents have been granted for changing gearing for the purpose of increasing or diminishing the speed of ma-chinery, without interfering with the motive power.

Letters patent have also been granted for improvements in jointed pitmans or connecting rods, which enables them to work evenly and with certainty, and at the same time adapt a long piston stroke to a short crank, or

vice versa.

ex

Letters patent have been granted for an improved mode of coupling line shafts. In most factories it is desirable that the shafts should be so coupled as to allow some vibration; but shafts for driving spinning, and some other. kinds of machinery, should revolve if possible without the slightest vibration. To effect this object, and for great strength, the snatts at the ends where they meet have discs of considerable diameter upon them, which, cept near the centre, lie against each other, forming a perfect joint. In the edges of these discs, parallel with the shaft and opposite each other, grooves are cut. A cup, having ribs on the interior of its cylindrical sides fitting the above mentioned grooves, is slipped on over them both, there being an opening in the bottom of the cup or collar to receive the shaft. Screws are then passed through the bottom of the cup and through both discs fastened to the shaft, binding the cup and discs firmly together. This joint is very strong. and inflexible. The torsive strain comes entirely on the ribs and grooves above mentioned, and the screws sustain only the longitudinal strain.

Letters patent have also been granted for an improved regulator for machinery. The patentee's principle may be variously and extensively applied. A small pump for air or water is connected with the machinery to be regulated and driven by it. This pump discharges itself into a small reservoir, having a float in it, which rises and falls with the fluid. In the lower part of the reservoir there is an adjustable stop cock, to discharge the fluid pumped into the reservoir by the action of the machinery. The float may be connected with the throttle valve of the steam engine, or may be connected with a brake or some similar device, for checking the motion of the machinery. The stop cock is then adjusted to the speed required, and while the machinery moves at the speed required, the water will remain at the so e height, and the float will be stationary. If the machinery should nove too fast, the fluid will be pumped into the reservoir faster than it can be discharged, and of course will rise carrying the float with it, and thus operating the throttle valve, and partially shutting off the steam, or bringing the brake upon the machinery and checking its motion. If the machinery moves too slowly, the water in the reservoir will descend, opening the throttle valve, and allowing a larger supply of steam, or removing the brake from the machinery. This regulator promises great usefulness, and is free from the prominent defects incident to most regulators now in use.

Nothing further in connection with mills and mechanical movements has transpired at my desk which need be made the subject of remark.

LUMBER AND MACHINERY FOR WORKING THEREIN.

About thirty patents have been granted this year for improvements belong. ing to this class. It comprehends a great variety of machinery to which important additions are annually made Machines for working in lumber