Of the various improvements in Microscopes originated by Dr. Goring, that which he conceives to be the most important is the construction of single magnifiers from adamant. The details relative to this novel class of instruments, I have been induced to lay before the public. Single microscopes naturally aplanatic, or at least sufficiently so for practical purposes, possess an incontestable superiority over all others, and must be recognised by the scientific as verging towards the ultimatum of improvement in magnifying glasses. The advantages obtained by the most improved compound engiscopes over single microscopes resolve themselves into _the attainment of vision without aberration with considerable angles of aperture_; but against this must be set the never-to-be-forgotten fact, that they only show us a _picture of an object instead of nature itself_; now a Diamond Lens shows us our real object without any sensible aberration like that produced by glass lenses; and we are entitled, I think, to expect new discoveries in miscrosopic science, even at this late period, _from very deep single lenses of adamant_[3]. I shall not fatigue my [p016] readers by describing the difficulties which were encountered in the prosecution of the design of making diamond lenses. Nature does not seem to permit us to produce any thing of surpassing excellence without proportional effort, and I shall simply say, that in its infancy the project of grinding and polishing the refractory substance of Adamant was far more hopeless than that of making achromatic glass lenses of 0.2 of an inch focus. I conceive it just to state that Messrs. Rundell and Bridge, of Ludgate-hill, had, at the time of the commencement of my labours, many Dutch diamond cutters at work, and that the foreman, Mr. Levi, with all his men, assured me, that it was impossible to work diamonds into spherical curves; the same opinion was also expressed by several others who were considered of standard authority in such matters.