Effect of Temperature
The modulus of elasticity of materials is dependent on temperature. For most materials, this temperature coefficient is large enough that variations in temperature significantly affect the timekeeping of a balance wheel and balance spring. The earliest makers of watches with balance springs, such as Robert Hooke and Christian Huygens observed this effect without finding a solution to it.
John Harrison, in the course of his development of the marine chronometer, solved the problem by a "compensation curb" – essentially a bimetallic thermometer which adjusted the effective length of the balance spring as a function of temperature. While this scheme worked well enough to allow Harrison to meet the standards set by the Longitude Act, it was not widely adopted.
Around 1765, Pierre Le Roy (son of Julien Le Roy) invented the compensation balance, which became the standard approach for temperature compensation in watches and chronometers. In this approach, the shape of the balance is altered, or adjusting weights are moved on the spokes or rim of the balance, by a temperature-sensitive mechanism. This changes the moment of inertia of the balance wheel, and the change is adjusted such that it compensates for the change in modulus of elasticity of the balance spring. The compensating balance design of Thomas Earnshaw, which consists simply of a balance wheel with bimetallic rim, became the standard solution for temperature compensation.
Read more about this topic: Balance Spring
Famous quotes containing the words effect of, effect and/or temperature:
“Considered physiologically, everything ugly weakens and saddens man. It reminds him of decay, danger, impotence; it actually reduces his strength. The effect of ugliness can be measured with a dynamometer. Whenever anyone feels depressed, he senses the proximity of something “ugly.” His feeling of power, his will to power, his courage, his pride—they decline with ugliness, they rise with beauty.”
—Friedrich Nietzsche (1844–1900)
“The sensation of seeing extremely fine women, with superb forms, perfectly unconscious of undress, and yet evidently aware of their beauty and dignity, is worth a week’s seasickness to experience.... To me the effect [of a Siva dance] was that of a dozen Rembrandts intensified into the most glowing beauty of life and motion.”
—Henry Brooks Adams (1838–1918)
“The bourgeois treasures nothing more highly than the self.... And so at the cost of intensity he achieves his own preservation and security. His harvest is a quiet mind which he prefers to being possessed by God, as he prefers comfort to pleasure, convenience to liberty, and a pleasant temperature to that deathly inner consuming fire.”
—Hermann Hesse (1877–1962)