XXV. On a searcher for aplanatic images applied to microscopes, and its effects in increasing power and improving definition

Abstract

In the observations which I have the honour to submit to the Royal Society, I purpose at present to describe as briefly as possible— I. Some experiments which suggested an inquiry into a method of raising microscopic power consistent with a corresponding improvement in the precision of definition, so generally destroyed by excessive amplification. II. I next purpose to give some account of the inquiries by which the construction of an aplanatic-image searcher was gradually arrived at; the object of which was to search for aplanatic foci, to compensate residuary errors by new spherical and chromatic corrections whilst amplifying power, and to increase the small interval existing between a deep objective and its object, whilst the focal perspective or depth was also increased