Documents by George Biddell Airy on research with pendulums

George Biddell Airy was the British Astronomer Royal in the middle of the nineteenth century.

He wrote many papers on various astronomical and physical subjects. The following two papers on his research with pendulums are fascinating, and the content of the first is critically important for all such research:

Click Here for a PDF file of Airy's paper "On the Vibration of a Free Pendulum in an Oval differing little from a Straight Line". This paper explains the mathematical and physical reasons for the Airy Precession.

To quote Maurice Allais, "The Airy effect is a major factor in the theory of the Allais pendulum". And the words of Airy are still very applicable today: "The difficulty of starting a free pendulum, so as to make it vibrate at first in a plane, is extremely great; and every experimenter ought to be prepared to judge how much of the apparent torsion of its plane of vibration is really a progression of apses due to its oval motion." This paper explains the reason for, and the magnitude of, this progression of apses.

Click Here for a PDF file of Airy's paper "... The Pendulum Experiments at Harton Pit". This paper details a series of precise experiments that Airy made in a coal-pit in the north of England, with the aim of deriving the mass of the Earth. This method has become known as the Airy method.

The description of the experimental details is superb; every pendulum experimenter ought to read this document and take on board the painstaking nature of the procedures involved in such work. I can't resist a few quotes:

"The careful perusal of the Lecture will shew the reader how, in the hands of Science and indomitable energy, results the most gigantic and absorbing may be wrought out by skilful combinations of acknowledged data and the simplest means."

"Commerce and Trade honor themselves, when, in their exciting career, they stop and hold forth a frank and generous hand to that which elevates and ennobles our race."

"[The experimenter] might consider that he stood in the same relation to the philosopher who employed himself in the more elevated parts of science, in which the quarryman stands to the architect; and if it should be found that he had cut out a sound corner-stone for the Temple of Science, he should be well satisfied with his success."


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