Should these observations be confirmed by other observers, it would seem to follow that the use of a chronometer renders a transit more exact, and therefore that it ought to be used in observatories.
Among the instruments employed by Captain Sabine, was a repeating circle of six inches diameter, made by order of the Board of Longitude, for the express purpose of ascertaining how far repeating instruments might be diminished in size:—a most important subject, on which the Board seem to have entertained a very commendable degree of anxiety.
The following extract from the "Pendulum Experiments" is important:
"The repeating circle was made by the direction, and at the expense of the Board of Longitude, for the purpose of exemplifying the principle of repetition when applied to a circle of so small a diameter as six inches, carrying a telescope of seven inches focal length, and one inch aperture; and of practically ascertaining the degree of accuracy which might be retained, whilst the portability of the instrument should be increased, by a reduction in the size to half the amount which had been previously regarded by the most eminent artists as the
