They rotate on steel shafts 21 in.
The farm of the future will rotate crops automatically and decide which fields to leave fallow.
We rotate every twelve months or so, Han explained.
P. 392), who prefers to rotate the cathode at a speed that maintains a peripheral velocity of at least woo ft.
It permits complete rotation of the tube and measurement of all angles in reversed positions of the circle; the handles that move the slides can be brought down to the eye-end, inside the tube, and consequently made to rotate with it; and the position circle may be placed at the end of the cradle next the eyeend where it is convenient of access.
Further, by causing the hour circle, and with it the polar axis, to rotate by clockwork or some equivalent mechanical contrivance, at the same angular velocity as the earth on its axis, but in the opposite direction, the telescope will, apart from the effects of refraction, automatically follow a star from rising to setting.
But the application of a magnetic field at right angles to the plane of the metal causes the equipotential lines to rotate through a small angle, and the points at] which the galvanometer is connected being no longer at the same potential, a current is indicated by the galvanometer.'
The general graphy, principle Arms a and arrangement b, one at eachstation and d B, are connected to the line wire, and are made to rotate simultaneously over metallic segments, 3, 4, and I', 3', 4', at the two stations, so that when the arm a is on segment i at A, then b is on segment I' at B, and so on.
The sample, arranged as a bundle of rectangular strips, is caused to rotate about a central horizontal axis between the poles of an upright C-shaped magnet, which is supported near 'its middle upon knife-edges in such a manner that it can oscillate about an axis in a line with that about which the specimen rotates; the lower side of the magnet is weighted, to give it some stability.
Hence if H varies the magnet will rotate in such a way that the couple due to torsion is equal to the new value of H multiplied by M.
The given series of positions will be assumed in succession if we imagine the laniin~ to rotate first about Jii until Jn comes into coincidence with J21, then about Jar until J24 comes into coincidence with J14, and so on.
They now seemed to rotate on one spot.
We note further that if a body be free to turn about a fixed point 0, there are three mutually perpendicular lines through this point about which it can rotate steadily, without further constraint.
If two magnets having moments M, M' are arranged at right angles to each other upon a horizontal support which is free to rotate, their resultant R will set itself in the magnetic meridian.
Pyrenaica, 3 to 6 in., is a pretty dwarf plant, requiring a warm position on the rockwork and a moist, peaty soil more or less gritty; it has rosettes of ovate spreading root-leaves, and large purple, yellow-centred, rotate flowers, solitary, or two to three together, on naked stalks.
As a fist example, suppose we have a flywheel free to rotate about a horizontal axis, and that a weight m hangs by a vertical string ~1~c~g FIG.
Thus in borage it is rotate, tubular in comfrey, funnel-shaped in hounds-tongue, and salvershaped in alkanet (Anchusa); the throat is often closed by scale-like outgrowths from the corolla, forming the so-called corona.
He published separately: - Istoria Universale (Roma, 1697), only one volume of which appeared; De Calendario et Cyclo Caesaris (1703); Hesperi et Phosphori nova Phaenomena (1729), in which he asserted Venus to rotate in 243 days; and (posthumously) Astronomicae et Geographicae Observationes Selectae (1737) and Opuscula Varia (1754).
This mirror can rotate about a horizontal axis which is at right angles to the line of collimation of the telescope, and is parallel to the surface of the mirror.
If, however, a theodolite, fitted with a telescope which can rotate about a horizontal axis and having an altitude circle, is employed, so that when observing a transit the altitude of the sun or star can be read off, then the time need only be known to within a minute or so.
Many types of mixing machines are obtainable; the favourite type is one in which the materials are placed in a large iron box which is made to rotate, thus tumbling the matrix and aggregate over each other again and again.
P. coeruleum (Jacob's Ladder), 2 ft., has elegant pinnate leaves, and long panicles of blue rotate flowers.
6) which could be made to rotate at a considerable speed by a multiplying gear, part of which is seen at X.
The bow drill (56) was used as a fire drill to rotate wood (55) on wood (57); and the cap (54) for such use was of hard stone with a highly polished hollow.
Faraday and others then discovered, as already mentioned, means to make the conductor conveying the current rotate round a magnetic pole, and Ampere showed that a magnet could be made to rotate on its own axis when a current was passed through it.
Barlow, Sturgeon and others then showed that a copper disk could be made to rotate between the poles of a horseshoe magnet when a current was passed through the disk from the centre to the circumference, the disk being rendered at the same time freely movable by making a contact with the circumference by means of a mercury trough.
Although the two-type beds have a reciprocating motion, as in the ordinary one-sided press, the two cylinders rotate towards each other.
The bascules rotate through an angle of 82°, and their rear ends in the bascule chambers of the piers carry 365 tons of counterweight, the total weight of each being 1070 tons.
Wollaston indeed had formed the expectation that he could make the conducting wire rotate on its own axis, and in April 1821 he came with Sir H.
A compound pendulum is a body of any form which is free to rotate about a fixed horizontal axis, the only extraneous force (other than the pressures of the axis) being that of gravity.
As an example of circular shifting may be cited the motion of the coupling rod, by which the parallel and equal cranks upon two or more axles of a locomotive engine are connected and made to rotate simultaneously.
In wheels which rotate continuously for one revolution or more, it is obviously necessary that the pitch should be an aliquot part of the circumference.
Hence also, in any pair of circular wheels which rotate continuously for one revolution or more, the ratio of the numbers of teeth and its reciprocal the angular velocity ratio must be expressible in whole numbers.
The relative velocity pet-pendicular to P~Pi of the teeth at their point of contactthat is, their velocity of sliding on each otheris found by supposing one of the wheels, such as I, to be fixed; the line of centres CXCi to rotate backwards round C~ with the angular velocity aj, and the wheel 2 to rotate round C2 as before, with the angular velocity az relatively to the line of centres CiC2, so as to, have the same motion as if its pitch-circle rolled,on the pitch-circle of the first wheel.
Backs of Teeth and Spaces.Toothed wheels being in general intended to rotate either way, the backs of the teeth are made similar to the fronts.
To make the teeth of a pair of endless screws fit correctly and work smoothly, a hardened steel screw is made of the figure of the smaller screw, with its thread or threads notched so as to form a cutting tool; the larger screw, or wheel, is cast approximately of the required figure; the larger screw and the steel screw are fitted up in their proper relative position, and made to rotate in contact with each other by turning the steel screw, which cuts the threads of the larger screw to their true figure.
Coupling of Parallel AxesOldhams CouplingA coupling is a mode of connecting a pair of shafts so that they shall rotate in the same direction with the same mean angular velocity.
If the axes of the ~ shafts are in the same straight line, the coupling consists in so connecting their the same straight line combinations of contiguous ends that they shall rotate as one piece; but if the axes are not in C
Linkwoyk in GeneralThe pieces which are connected by linkwork, if they rotate or oscillate, are usually called cranks, beams and levers.
Coupling of Parallel Axes.Two or more parallel shafts (such as those of a locomotive engine, with two or more pairs of driving wheels) are made to rotate with constantly equal angular velocities by having equal cranks, which are maintained parallel by a coupling-rod of such a length that the line of c000exion is equal to the distance between the axes.
When the cones are pressed together or engaged, their friction causes the pulley to rotate along with the shaft; when they are disengaged, the pulley is free to stand still.
The corresponding value of a, namely ~ gc/w, is called the critical velocity of the shaft, and is the speed at which the shaft ceases to rotate stably and at which centrifugal whirling begins.
In 1821 Michael Faraday (1791-1867), who was destined later on to do so much for the science of electricity, discovered electromagnetic rotation, having succeeded in causing a wire conveying a voltaic current to rotate continuously round the pole of a permanent magnet.
On bringing down on to the mercury surface a wire conveying an electric current, and allowing the current to pass through the mercury and out at the bottom, the magnetic pole at once began to rotate round the wire (Exper.
Rumford then turned up a hollow cylinder which was cast in one piece with a brass six-pounder, and having reduced the connexion between the cylinder and cannon to a narrow neck of metal, he caused a blunt borer to press against the hollow of the cylinder with a force equal to the weight of about ro,000 lb, while the casting was made to rotate in a lathe.
It, it, The three lobes of the lower lip of the rotate corolla.
(?) and viii., and the satellite of Neptune.); while, to make the argument complete, the planets, so far as they can be observed, rotate on their axes in the same manner.
As this vast mass cooled it must by the laws of heat have contracted towards the centre, and as it contracted it must, according to a law of dynamics, rotate more rapidly.
The shell is represented as fixed, while the head and foot rotate from left to right.
Supposing Ewing's hypothesis to be correct, it is clear that if the magnetization of a piece of iron were reversed by a strong rotating field instead of by a field alternating through zero, the loss of energy by hysteresis should be little or nothing, for the molecules would rotate with the field and no unstable movements would be possible.'
I), the flowers are rotate, that is to say, the long tube is replaced by a very short one.
Palustris, is a perennial plant growing to a height of 6 to 18 in., with rootstock creeping, stem clothed with lax spreading hairs, leaves light green, and somewhat shining, buds pink, becoming blue as they expand, and corolla rotate, broad, with retuse lobes and bright blue with a yellow centre.
If small paper rings are put on a monochord wire they rotate through these vibrations when the wire is bowed.
If the experiment was successful the table would rotate with considerable rapidity, and would occasionally rise in the air, or perform other movements.
In Se p tember of that year he discovered that the force required for the rotation of a copper disk becomes greater when it is made to rotate with its rim between the poles of a magnet, the disk at the same time becoming heated by the eddy or "Foucault currents" induced in its metal.
Suppose, for example, that a flywheel is rotating with angular velocity n about its axis, which is (say) horizontal, and that this axis is made to rotate with the angular velocity ~ in the horizontal plane.
37 rotate about its vertical diameter.
As a first application of the equations (2) take the case of a solid constrained to rotate with constant angular velocity to about a fixed axis (1, m, n).
That, when both pieces rotate, their axes, and all their points of contact, lie in the same plane.
When the clutch is moved towards the hoop, its arms catch those of the hoop, and cause the hoop to rotate and to communicate its rotation to the pulley by friction.
The elastic resistance evoked by this deflexion is proportional to the deflexion, so that if c is a constant depending upon the form,, material and, method of support of the shaft, the following equality must hold if the shaft is to rotate stably at the stated speed- -~ (y+e)ai=cy, from which y=Wafe/(gcWa2).
This circle to measure the polar distance of any star seen in the telescope, and these readings will also be true (apart from the effects of atmospheric refraction) if we rotate the instrument through any angle on the axis A A.
Other water engines, similarly connected, with keys at the observer's hands, rotate the dome and perform the quick motions in right ascension and declination.