Two "invariable" seconds pendulums were swung, one in front of the upper and the other in front of the lower comparison clock after the manner of Kater, and these invariables were interchanged at intervals.
The simple pendulum would be set swinging by the varying attraction and from its amplitude after a known number of swings of the outside pendulums G could be found.
Joly has suggested that G might be determined by hanging a simple pendulum in a vacuum, and vibrating outside the case two massive pendulums each with the same time of swing as the simple pendulum.
Semicircular and Cycloidal Times of Oscillation are to each other as 34 to 29: That in both the Length of the Strings of Pendulums are in a duplicate Proportion to their Times of Oscillation; and that the Heights of Roofs, &c.
Are several Pendulumsof several Sorts of Matter, heavy and light; where the Centers of Suspension and Oscillation are equally distant, and the Times of those Oscillations are all equal.
Rifle and ballistic pendulums on the northeast, and the steam boiler house on the northwest portions.
Without entering into the physiological structure of the eye, we may say that it has usually been assumed that the pendulums are the ends of nerves which vibrate with the waves of light; but this seems rather doubtful.
This wonderful timekeeping is done with seconds pendulumsof about 39 in.
Nor is any adjustment of their pendulums necessary, or setting of the hands, as the correction of their small variations is effected by slight changes in the air pressure within the glass cylinders.
Clocks regulated by star transits, as at present, would divide this decimally, the fourth place being near enough to make the new pendulums of convenient length.
A vibratory motion of the pendulums to and from the central axis would thus be productive of an alternate storage and return of energy.
When the central spindle AB is at rest the pendulums hang vertically; when energy is applied to the system, and AB is thereby caused to rotate, the spherical masses M and M{1} will rise by circular paths about C and D.
The phenomena would be of precisely the same nature as those already alluded to in the case of the system of rotating pendulums (Sec.
The movements of the rotating pendulums will also be accompanied by other energy operations associated with bearing friction and windage (Secs.
But this arrangement of rotating pendulums may be extended so as to include other features.
The Kater invariable pendulums were used to investigate the internal constitution of the earth.
Earlier, he had been professor of physics at the University of Tokyo and had directed observations of pendulums for the determination of gravity on Fujiyama and at Tokyo.
Repsold and Sons in Hamburg constructed pendulums from the specifications of Bessel for European gravity surveys.
A description of the Peirce invariable, reversible pendulums was given by Assistant E.
The problem of flexure of the case is overcome by the Faye-Peirce method (see text) in which two dynamically matched pendulums are swung simultaneously, 180 deg.
As we have seen, such invariable pendulums had been used by Bouguer and Kater, and after the experiences with the Repsold apparatus had been recommended again by Baeyer for relative determinations.
The 19th century witnessed the development of the theory and practice of observations with pendulums for the determination of absolute and relative values of gravity.
Peirce, in 1883, had discovered that the recesses cut in his pendulums for the insertion of tongues that carried the knives had resulted in the flexure of the pendulum staff.
Hirsch, who declared that exact observation of passages of a "double pendulum" would be difficult and that two pendulums swinging so close together would interfere with each other.
Airy sought to determine the density of the earth by observing the times of swing of pendulums at the top and bottom of a mine.
The first Mendenhall pendulumswere made of bronze, but about 1920 invar was chosen because of its small coefficient of expansion.
See, I have set twopendulums on these two clocks swinging different ways; one from right to left, the other from left to right.
Only in the same atmosphere or at an equal distance from the centre of the earth can two pendulums make the same number of vibrations in a given time.
To be sure, two pendulums never tick precisely together, so as to give but one tone.
The pendulums swung more and more determinedly each in its own direction.
In a few days the two pendulums swung together, but the hearts of husband and wife held each its own accustomed motion.
In order that one pendulum shall oscillate one-half as fast as another, the length of the pendulums must be as four to one.
The boxes hanging by eleven feet, made a couple of pendulums exactly equal in weight and figure, and equally receiving the resistance of the air.
He found, also, that the rate of oscillation for pendulums of different lengths varies according to a simple law.
Similarly, by lengthening the pendulums nine times, the oscillation is reduced to one-third, In other words, the rate of oscillation of pendulums varies inversely as the square of their length.
And this may be try'd, by letting two equal Pendulums fall against one another from equal heights.
If the Pendulums be of Lead or soft Clay, they will lose all or almost all their Motions: If of elastick Bodies they will lose all but what they recover from their Elasticity.
The two pendulums oscillate constantly in the inverse sense the one to the other.
We show another escapement with two pendulums in Fig.
The two pendulums oscillate inversely one to the other, and one after the other receives an impulse.
It will be seen that no two pendulums have the same length.
As thependulums are of different lengths they must necessarily swing at different rates per second.
To make the longer pendulums swing, longer movements of the table top must be made.
But if we draw one pendulum a great deal to one side, and the other only a little, the two pendulums still swing sympathetically.
If we draw both pendulums aside and then release them, they swing together and return together.
Thus my child and I went on, like two pendulums crossing each other in their swing, trying to reach the same dead beat of mutual intelligence.
The measurements were particularly difficult by reason of the length of the pendulums employed, these generally being second-pendulums over 1 metre long.
Also, pendulums with equal cord length swing at the same rate, regardless of the substance, weight, or shape of the material at the end.
Clockmaker and Quaker Benjamin Huntsman was struck with the difficulty of finding finely tempered steel for the springs of his watches and pendulums of his clocks.
Therefore when it came to testing out his big turret clocks, he had to cut a hole in the floor in order to give their long pendulums room to swing.
You will recall that early in clock history there were some pendulums of a very unsatisfactory nature in use--pendulums that were regulated by weights and dangled at the back or across the front of old brass clocks.
Some of these had brass works and seconds pendulums and ran eight days, and others were thirty-hour clocks with works of wood.
At length brass pendulums which, they discovered, made the most trouble, were replaced by those of iron or lead which, being of softer material, expanded and contracted more readily.
Nor did the novel innovation of the pendulum do much good at first, although theoretically makers of clocks conceded pendulums to be a scientific advance over older methods.
Even pendulums were not introduced in any practical form until 1657.
Makers had, however, been convinced by this time that pendulums did not look well hanging down across the faces of clocks, and so they now put them at the back, their swingings being frequently concealed by projecting dials.
Craig was still standing by the table, but now the pendulumswith the magnets and needles and the drums worked by clockwork were before him.
Almost lovingly he touched the pendulums on the table.
The pendulums vibrate, and the needles trace a broken line on the paper on each drum.
At the laboratory he unlocked a glass case and took out a little instrument which looked like two horizontal pendulums suspended by fine wires.
I could not help but think of the two pendulums on the shelf behind the curtain, but Craig said nothing for a moment to indicate that he referred to that apparatus.
Behind it he placed on a shelf the apparatus composed of the pendulums and magnets.
Afterward pendulums were built of dimensions further reduced to about two and one half inches in length, with periods of oscillation of one fourth of a second.
This alloy is already employed for pendulums with satisfactory results, both at the Naval Observatory and at the Bureau of Standards, in Washington.
At the Bureau of Standards and the Naval Observatory at Washington, pendulums of invar have been adopted with gratifying results.
In the other horizontal pendulums and in the magnetographs, the method of registration is photographic.
The heavy masses in the horizontal pendulums were tilted instead of remaining as steady points.
Among the more important of these instruments are long vertical pendulums, horizontalpendulums of various forms, and magnetographs.
The planes in which their pendulums oscillated are shown by the lines lettered A, B, C, and D in Fig.
As the pendulums of B and C might make a few staggering oscillations before their final arrest, Major Dutton assigns 9h.
In this seismograph, the pendulums are provided with pointers, the tips of which touch vertical sheets of paper attached to the sides of an upright rectangular box.
The pendulums are provided with a long slot to enable them when the table motion reverses to swing over and drag in the opposite direction (as shown in Fig.
In the guides on the table there are provided pockets or slots in which are pivoted pendulums of the form shown in Fig.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "pendulums" in a variety of sentences. We hope that you will now be able to make sentences using this word.
