Of lost works by Archimedes we can identify the following: (I) investigations on polyhedra mentioned by Pappus; (2) Archai, Principles, a book addressed to Zeuxippus and dealing with the naming of numbers on the system explained in the Sand Reckoner; (3) Peri zygon, On balances or levers; (4) Kentrobarika, On centres of gravity; (5) Katoptrika, an optical work from which Theon of Alexandria quotes a remark about refraction; (6) Ephodion, a Method, mentioned by Suidas; (7) Peri sphairopeoia, On Sphere-making, in which Archimedes explained the construction of the sphere which he made to imitate the motions of the sun, the moon and the five planets in the heavens.
In the Wheatstone automatic apparatus three levers are placed side by side, each acting on a set of small punches and on mechanism for feeding the paper forward a step after each operation of the levers.
28, and the levers are adjusted so that the left-hand one moves a, b, c and punches a row of holes across the paper (group i in the figure), the middle one moves b only and punches a centre hole (2 in the figure), while the right-hand one moves a, b, d, e and punches O p p Oa Oa' Ob Od 0?
Each instrument is provided with a keyboard, resembling that of a small piano, the key levers of which communicate with a circular row of vertical pins.
In the Rowland multiple method of telegraphic working, the transmitter consists of a mechanical keyboard provided with a series of levers, which effect certain combinations of positive and negative currents for each letter.
The function of the " combiner " in each receiving instrument is so to group the received combination of positive and negative currents that they operate polarized relays in such a manner that the position of the tongues corresponds with the operation of the levers on the transmitter.
The telautograph is on a similar principle to the Cowper apparatus, the motion of the transmitting pencil or stylus used in writing being resolved by a system of levers into two component rectilinear motions, which are used to control and vary the currents in two distinct electrical circuits.
Each coil is attached to a shaft by a bell crank arrangement, and to these shafts there is secured a system of levers similar to that at the transmitter carrying the receiving pencil at the junction.
When one of the levers of K is depressed, the condenser C 1 and the cable, and the condenser C2 and the artificial cable, are simultaneously charged in series; but, if the capacity of C 1 bears the same proportion to the capacity of the cable as the capacity of C2 bears to the capacity of the artificial cable, and if the other adjustments are properly made, no charge will be communicated to C3.
The final settlement of a rule requiring brake-levers to be fitted on both sides of goods-wagons was, however, deferred, owing to objections raised by certain of the railway companies.
While moving vehicles by capstans, turn tables, props, levers, &c...
The movements of bones and muscles were referred to the theory of levers; the process of digestion was regarded as essentially a process of trituration; nutrition and secretion were shown to be dependent upon the tension of the vessels, and so forth.
2, it will be balanced by a thrust W lb applied to the other piston of area B ft.', where p = P/A=W/B, (I) the pressure p of the liquid being supposed uniform; and, by making the ratio B/A sufficiently large, the mechanical advantage can be increased to any desired amount, and in the simplest manner possible, without the intervention of levers and machinery.
The controlling levers and draught arrangements are similar to those in the "sulky" plough.
The most successful of the first class, or pick machines, that of William Firth of Sheffield, consists essentially of a horizontal pick with two cutting arms placed one slightly in advance of the other, which is swung backwards and forwards by a pair of bell crank levers actuated by a horizontal cylinder engine mounted on a railway truck.
The former contrivances consist essentially of levers or cams with toothed surfaces or gripping shoes mounted upon transverse axes attached to the sides of the cage, whose function is to take hold of the guides and support the cage in the event of its becoming detached from the rope.
This replaced the propeller of the ship whose engines were to be tested, and the outer casing was held from turning by a suitable arrangement of levers carried to weighing apparatus conveniently disposed on the wharf.
In the Farcot form the guide pulleys are attached to separate weighing levers placed horizontally below the apparatus.
In a belt dynamometer built for the Franklin Institute from the designs of Tatham, the weighing levers are separate and arranged horizontally at the top of the apparatus.
The dressed stones for great buildings were pecked out of the ledges, and broken off with levers in pieces much too large for their needs.
9, shows the relative position of the dies and levers more clearly.
In some cases hauling tackle is used, in others power is applied by levers and ratchets to the rollers on which the girders travel.
The sepulchral chambers are separated by a short passage, and are cut off from the gallery by stone doors made of a single slab which can be moved up and down by levers, like a portcullis.
As shown in the figure, it is evident that the motion of o in the line sop would not be recorded, and to obtain a complete record of horizontal movements it is necessary to have two levers at right angles to each other.
Here the style s of the pendulum rests in slots in the short arms of two writing levers pivoted at o and o'.
The length of the short arms of the levers is usually s or; a of the long arms.
To obtain a complete record of horizontal motion, two of these pendulums are placed at right angles; and by cranking one of the writing levers, o'p', as shown in the plan of fig.
With pendulums of shorter length, say metres, it is necessary to have a multiplication 80 to too fold by a double system of very light levers, in order to render the extremely slight tilting of their support perceptible.
There is also an extension from the upper surface of the pendulum, in contact with a system of levers and rods attached to the case; an air-dampkig cylinder is fitted to annul the free vibrations of the pendulum.
The wheel W is therefore mounted on a guided rod, which is forced upwards by suitable levers and weights, and this relief of pressure is precisely proportional to the pressure on the respective bearings.
Silver-on-glass mirror (weighing about one ton) rests at the lower end of the tube on a support-system consisting of a large number of weighted levers which press against the back of the glass and distribute the load.
Similar weighted levers around the circumference of the mirror provide the edge support.
The platen is attached to the centre of the lever by a square bar of iron, and its vertical descent is assured by two projecting guides, one from each cheek; it is then raised from the type-forme, and the iron bar carried back by two levers - the one attached to and above the head and weighted with the eagle; the other behind the press, attached to the arm to which the coupling-bar is fixed, and which also has a weight at the end.
As illustrative examples of the form of wings alluded to, those of the beetle, bee and fly may be cited - the pinions in those insects acting as helices, or twisted levers, and ' Revue des tours scientifiques de la France et del' Etranger, 1869.
The movements to be registered are transferred to the style or pen by one or more levers, and the pen in turn transfers them to the cylinder, where they appear as legible tracings.
To meet these peculiarities the insect, bird and bat are furnished with extensive flying surfaces in the shape of wings, which they apply with singular velocity and power to the air, as levers of the third order.
Unequal-armed balances may be divided into (I) balances consisting of a single steelyard; (2) balances formed by combinations of unequal-armed levers and steelyards, such as platform machines, weighbridges, &c.
8 the weight on the platform is transferred by levers to the vertical steel band, A, which is wrapped round an arbor on the axle of the disk - wheel, B, to which is rigidly attached the toothed segment, C. The weight, D, is rigidly attached to the axle of the wheel, B, and the counterbalance, E, is hung from the wheel, B, by means of a cord wrapped round it.
They are also used as trade computing machines, as in the case of the machine made by the Computing Scale Company, Dayton, Ohio, U.S.A. In this machine the goods to be priced are placed on the platform of a small platform machine whose steelyard is adjusted to balance exactly the weight of the platform, levers and connexions.
The power is applied at the end of the long arm of the steelyard and multiplied by levers from loo to 500 times, so that the weights used are small and handy.
The platform and the load upon it are carried on four knife-edges, two of which, x 1 and x 2, are shown, and the load is transferred to the steelyard by the two levers shown, the upper one CD being known as the long body," and the lower, one EF as the " short body."
In another arrangement two similar triangular levers take bearing on opposite sides of an intermediate lever which communicates their pressures to the steelyard; this is a very sound and simple arrangement for ordinary long weighbridges.
There are many kinds of weighing machines depending for their action on combinations of levers, and arranged to meet special requirements.
Such are coal platform machines for weighing out [[[Unequalarm Ed]] coal in sacks, the levers of which are arranged as in the ordinary platform machines, but for the sake of compactness the steelyard is returned back over the long body, and when loaded with the proper weight indicates the correct weight of the coal in the sack by its end Elevation.
The knife-edges on which the hopper rests are on two hori - zontal levers, one on each side of the hop From the Notice issued by the Standards Department per.
These levers are of the Board of Trade, by permission of the Controller carried by knife-edge of H.M.
The cam shaft and the cam then begin to revolve, and the flitch-plate is gradually lowered till the knife-edge bearings of the hopper are received on the knife-edges of the main measuring levers, and the load is then weighed by the levers and the spring-balance.
It consists of a platform which is carried by levers arranged in the manner of an ordinary platform machine, which are connected with the registration mechanism by a vertical rod.
The engagement of the pulley and clutch is determined by a hand-controlled block F sliding on the shaft, the movement of which is communicated to the rightand left-handed screw shafts by links G connected to the levers H.