Former Clock & Watchmakers and Their Work: Including an Account of the Development of Horological Instruments from the Earliest Mechanism, with Portraits of Masters of the Art

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E. & F.N. Spon, 1894 - 397 pages
 

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Page 118 - thermometer kirb,' he himself says, ' is composed of two thin plates of brass and steel, riveted together in several places, which, by the greater expansion of brass than steel by heat and contraction by cold, becomes convex on the brass side in hot weather and convex on the steel side in cold weather; whence, one end being fixed, the other end obtains a motion corresponding with the changes of heat and cold, and the two pins at the end, between which the balance spring passes, and which it alternately...
Page 194 - Because of the various expansion of metals, respecting which no two pyrometers agree ; the changeable nature of the atmosphere ; the uncertainty as to the true level of the sea ; the extreme difficulty of measuring accurately the distance between the point of suspension and the centre of oscillation, and even of finding that centre...
Page 28 - The drawing is a plan of the escape wheel and verge as they lie in the watch. The width of the pallets apart from centre to centre is equal to the diameter of the wheel. A tooth of the escape wheel is just leaving the upper pallet (c.) ; as it drops off, the...
Page 256 - The pendulum is traveling in the direction indicated by the arrow, and the left-hand pallet has just given impulse. The pendulum rod in its swing will push the right-hand pallet far enough for the leg of the front locking plate, which is now resting on the block, to escape. Directly it escapes, the left-hand pallet is lifted free of the pendulum rod by the lowest of the three pins. After the locking wheel has passed through 60°, a leg of the back locking plate is caught by the locking block on the...
Page 250 - ... in the introduction of the dead-beat escapement. In Fig. 5 are shown both the anchor or recoil escapement and the dead-beat escapement. In the first, shown on the left, the pendulum moving to the left has just escaped a tooth at the left-hand pallet and allowed a tooth to fall on the righthand one. The pendulum, however, still continues its swing to the left, and in consequence the pallet pushes the wheel back, thus causing the recoil that gives the name to the escapement. It is only after the...
Page 121 - Instruments of themselves to play exceeding well on the Flute, Flaggelet, or Organ, Setts of Country dances, Minuets, Jiggs, and the Opera Tunes, or the most perfect imitation of the Aviary of Birds above mentioned, fit for the Diversion of those in places where a Musician is not at Hand. He makes also Organs performing of themselves Psalm Tunes with two, three, or more Voluntaries, very Convenient for Churches in remote Country Places where Organists cannot be had, or have sufficient Encouragement....
Page 161 - A moving panorama, descriptive of day and night. Day is represented by Apollo in his car drawn by four spirited coursers, accompanied by the twelve hours ; and Diana in her car drawn by stags, attended by the twelve hours, represents Night. 2. Two gilt figures in Roman costume, who turn their heads and salute with their swords as the panorama revolves, and also move in the same manner while the bells are ringing.
Page 102 - ... go exact and keep equaller time than any now made without this regulator (examined and proved before his Highness the Lord Protector by such doctors, whose knowledge and learning is without exception), and are not subject to alter by change of weather, as others are, and may be made to go a week, or a month, or a year, with once winding up, as well as those that are wound up every day, and keep time as well ; and is very excellent for all house clocks that go either with springs or weights ;...
Page 92 - Whereas several who have been curious in measuring time have taken notice that the vibrations of a pendulum are slower in summer than in winter, and have very justly supposed this alteration has proceeded from a change of length in the pendulum itself, by the influence of heat and cold upon it, in the different seasons of the year; with a view, therefore, of correcting, in some degree, this defect of the pendulum, I made several trials, about the year 1715, to discover whether there was any considerable...
Page 104 - Ut tensio, sic vis, meaning that the force is proportionate to the tension. Hooke proposed to patent his discovery, and, in his own words, " Sir Robert Moray drew me up the form of a patent, the principal part whereof, viz. the description of the watch, is nis own hand writing, which I have yet by me; the discouragement I met with in the progress of this affair made me desist for that time ". Several watches were made by Tompion under Hooke's supervision.

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