Roots of their lengths; which doth not answer to Experience. But the
Errors of the Rays arising from the different Refrangibility, are as the
Apertures of the Object-glasses; and thence to make Telescopes of
various lengths, magnify with equal distinctness, their Apertures and
Charges ought to be as the square Roots of their lengths; and this
answers to Experience, as is well known. For Instance, a Telescope of 64