By ca-sing two conical surfaces of cast-iron immersed in mercury and contained in an iron vessel to rub against one another when pressed together by a lever, Joule obtained 776.045 foot-pounds for the mechanical equivalent of heat when the heavy weights were used, and 774.93 foot-pounds with the small driving weights.
Circuit-closing apparatus called a relay, which is practi cally an electromagnetic key which has its lever attached to the armature of the magnet and which can be worked by a very weak current.
The microphonic arrangement consisted of a spring S, about the hundredth of an inch thick and the eighth of an inch broad, fixed at one end to a lever L, and carrying at its free extremity a brass block W.
In the earlier forms of instrument the record was made by embossing lines on a ribbon of paper by means of a sharp style fixed to one end of a lever, which carried at the other end the armature of an electromagnet.
He proposed to make the armature partake of the vibrations of the atmosphere either by converting it into a suitable vibrator or by controlling its vibrations by a stretched membrane of parchment armature had the form of a hinged lever one end, which pressed against the centre.
If therefore the outer rail is laid at a level above that of the inner rail at the curve, overturning will be resisted more than would be the case if both rails were in the same horizontal plane, since the tilting of the vehicle due to this " superelevation " diminishes the overturning moment, and also increases the restoring moment, by shortening in the one case and lengthening in the other the lever arms at which the respective forces act.
In these the central bar which connects the two end links has screw threads cut upon it,;and by means of a lever can be turned so as either to shorten the coupling and bring the vehicles together till their buffers .are firmly pressed together, or to lengthen it to permit the end link to be lifted off the hook.
The British Museum had been formed, and he had access to everything it contained in addition to the abundant materials afforded him by the private museum of Sir Ashton Lever.'
The sand-pump reel is set in motion by pressing a lever, the reel being then brought into contact with the face of the band-wheel.
The sand-pump descends by gravitation, and its fall is checked by pressing hack the lever, so as to throw the reel against a post which serves as a brake.
This may consist simply in attaching one end of the wire to an index lever and the other to a fixed support, or the elongation of the wire may cause a rotation in a mirror from which a ray of light is reflected, and the movement of this ray over a scale will then provide the necessary means of indication.
That eminent scholars both in the synagogue and in the church should have been induced to believe in its antiquity is owing to the fact that the Zohar embodies many older opinions and doctrines, and the undoubted antiquity of some of them has served as a lever in the minds of these scholars to raise the late speculations about the En Soph, the Sephiroth, &c., to the same age.
The rod touches this pole at a single point, and is pulled away from it by the action of a lever, the long arm of which is graduated and carries a sliding weight.
On starting to hoist, the rope winds from the small towards the large end of the drum, the lever arm, or radius of the coils, increasing as the weight of Winding Engine.
The blower places the glass in the mould, closes the mould by pressing a lever with his foot, and either blows down the blowing iron or attaches it to a tube connected with a supply of compressed air.
1070 I 060 960 950 930 911 889 883 858 825 823 810 781 771 753 745 727 722 705 681 668, of squares and cubes, calculated from 1 to 60, have been found at Senkera, and a people who were acquainted with the sun-dial, the clepsydra, the lever and the pulley, must have had no mean knowledge of mechanics.
The weight of these implements necessitates some provision for turning them at the headlands, and this is supplied either by a bowl wheel, enabling the plough to be turned on one side, or by a pair of wheels cranked so that they can be raised by a lever when the plough is working.
The furrow wheels are placed on inclined axles, the plough beam being carried on swing links, operated by a hand lever when it is necessary to raise the plough out of the furrow.
For shallow water greater precision and certainty are obtained by using a lever actuated by a weight slipped down the line to cause the reversal, as in the patterns of Rung, Mill and others.
The discoveries of Copernicus were eagerly accepted by him, and he used them as the lever by which to push aside the antiquated system that had come down from Aristotle, for whom, indeed, he had a perfect hatred.
The cage is then lifted by the engine clear of the keeps, which are opened by a lever worked by hand, and the empty tubs start on the return trip. When the cage has several decks, it is necessary to repeat this operation for each, unless there is a special provision made for loading and discharging the tubs at different levels.
Compensation is effected by the lever L inserted at B.
The external forces holding the brake from turning are W, distant R from the axis, and the reaction, W 1 say, of the lever against the fixed pin P, distant R1 from the axis.
The relative angular displacement is proportional to the radius of the circle described by the end of a light lever operated by mechanism between the spring-connected parts.
The automatic sight consists of a bent lever roller cam m, also secured by the bolt e to the carrier; the lower end of the lever carries the cam roller n, which is constrained to move in the cam p by means of the spring in the spring-box g; the rear end of the horizontal arm of the lever is formed into jaws v; the same action of the clutch t which releases the worm and hand-wheel forces a catch on a vertical stem u into the jaws of the lever, and fixes the rocking and sight bars rigidly to it.
The movement of the sights can now only be effected by means of the elevating gear of the gun, acting by means of the movement of the vertical arm of the bent lever, and its movement is constrained to follow the cam, which is cut in such a way that for any given elevation of the gun the sight bar is depressed to the angle of sight for the range corresponding to the elevation; b is a lever for making allowance for state of tide, and c is the scale on which the rise and fall in feet above and below mean sea-level are marked.
In later patterns, the sight is automatic pure and simple, the lever is rigidly attached to the rocking-bar, and the range scale and gear for raising the sights dispensed with, much as shown in fig.
The coining presses now used are all modifications of the lever press invented by Uhlhorn of Grevenbroich near Cologne in 1839.
The lever M worked from the front of the machine causes the flywheel to be connected with the driving-wheel and the machine starts.
The collar A' is then raised by the lever G so as to encircle the blank, and the upper die which is held at A is brought down.
The forceps are then opened and the beam released, but at this moment the levelling bar F is allowed to drop momentarily by a bent lever G acting on the pin G', until the ends of F press down on a stirrup in each hanger at H, H.
B is the bob of a pendulum, with its style s passing through a slot in the short arm of a light lever, sop, pivoted at o, and with its outer end resting upon a revolving cylinder covered with smoked paper.
Its lower end was fitted with a ball-and-socket joint to enable it to be laid in any direction, and beneath this is a screw which can be screwed by means of a small lever into a piece of wood embedded in the side of a trench.
The adductor muscles placed in the concavity of the shells act upon the long arms of the lever at a mechanical advantage; their contraction keeps the shells shut, and stretches the ligament or spring h.
A, b, right and left valves of the shell; c, d, the umbones or short arms of the lever; e, f, the long arms of the lever; g, the hinge; h, the ligament; i, the adductor muscle.
The lever G at once oDT FIG.
The experiments with this form were not successful, and, with the view of making the moving parts as light as possible, he substituted for the comparatively heavy lever armature a small piece of clock spring, about the size of a sixpence, glued to the centre of the diaphragm.