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arbor astronomical clock axis balance spring balance wheel barrel bell Berthoud brass carries centre circle circumference cock compensation contrate wheel contrived cylinder dead beat degree detent dial distance ditto divided divisors edge equal equation Ferdinand Berthoud fixed force fourth wheel fraction frame fusee give given gridiron pendulum half hammer hole inch in diameter isochronism lever locking lower end means minute hand minute wheel month wheel motion multiplied nearly notch number of teeth number of turns number of vibrations pallet pendulum ball pendulum rod pendulum spring piece of brass pitching pivots plate pulley pyrometer quarter quotient rack ratchet ratio regulating remontoir revolution roller round scapement sector side socket space square steel rods striking stud supposed swing wheel thick third wheel time-keeper tion tooth tube turret clocks verge watch weight wheel teeth wheels and pinions whole number zinc
Page 8 - The wheels, in any sort of movement, when at liberty, or free to turn, and when impelled by a force, whether it is that of a weight or of a spring, would soon allow this force to terminate ; for, as the action of the force is constant from its first commencement, the wheels would be greatly accelerated in their course, and it would be an improper machine to register time or its parts. The necessity of checking this acceleration, and making the wheels move with a uniform motion, gave rise to the invention...
Page 272 - ... on the top of the mucilage. When time has thus completed the operation, the pure oil must be poured off into very small phials, and kept in a cool place, well corked, to preserve it from the air* AERIAL NAVIGATION.
Page 469 - Description of two methods, by which the Irregularities in the motion of a Clock, arising from the influence of Heat and Cold upon the rod of the pendulum, may be prevented, etc.
Page 316 - Before the introduction of railways, people used to set their clocks by the sun. But owing to the obliquity of the ecliptic and the eccentricity of the earth's orbit around the sun, the intervals between successive passages of the sun are not exactly equal. The consequence is that, if a clock keeps exact time, the sun will sometimes pass the meridian before and sometimes after twelve by the clock. When this was understood, a distinction was made between apparent...
Page 287 - Thus, supposing the given number of equal divisions of a circle on the dividing plate to be 69 ; subtract 9, and there will remain 60. Every circle is supposed to contain 360 degrees : therefore say, As the given number of parts in the circle, which is 69, is to 360 degrees, so...
Page 471 - Les Longitudes par la Mesure du Temps, ou Méthode pour déterminer les Longitudes en Mer, avec le secours des Horloges marines...
Page 471 - Eclaircissements sur l'invention, la théorie, la construction et les épreuves des nouvelles machines proposées en France, pour la détermination des longitudes en mer par la mesure du temps...
Page 4 - London, vol. ii. p. 55. The clock at St. Mary's, Oxford, was also furnished in 1523, out of fines imposed on the students of the university.
Page 271 - Put a quantity of the best olive oil into a phial with two or three times as much water, so that the phial may be about half full. Shake the phial briskly for a little time, turn the cork downwards, and let most part of the water flow out between the side of the cork and the neck of the phial.