Continuing, the construction of the microscope and specimen mounting techniques are described:
It were endless to enter into any Particulars, of what is to be observed in any of these Objects, or indeed to give any Account of Mr. Leeuwenhoek’s Discoveries ; they are so numerous as to make up a considerable Part of the Philosophical Transactions, and when collected together, to fill four pretty large Volumes in Quarto, which have been publish’d by him at several Times : And of such Consequence, as to have opened entirely new Scenes in some Parts of Natura! Philosophy, as we are all sensible, in that famous Discovery of the Animálculo, in Semine Masculino, which has given a perfectly new Turn to the Theory of Generation, in almost all the Authors that have since wrote upon that Subject.
For the Construction of these Instruments, it is the fame in them all, and the Apparatus is very simple and convenient : They are all single Microscopes, consisting each of a very small double Convex-Glass, let into a Socket, between two Silver Plates rivetted together, and pierc’d with a small Hole : The Object is placed on a Silver Point, or Needle, which, by Means of Screws of the same Metal, provided for that Purpose, may be turn’d about, rais’d, or depress’d, and brought nearer, or put farther from the Glass, as the Eye of the Observer, the Nature of the Object, and the convenient Examination of its several Parts may require.
Mr. Leeuwenhoek fix’d his Objects, if they were solid, to this Silver Point, with Glew -, and when they were Fluid, or of such a Nature as not to be commodiously view’d unless spread upon Glass, he first fitted them on a little Plate of Talk, or excessively thin-blown Glass, which he afterwards glewed to the Needle, in the fame Manner as his other Objects. The Observation, indeed, of the Circulation of the Blood, and some others, require a somewhat different Apparatus, and such a one he had, to which he occasionally fix’d these same Microscopes ; but as it makes no Part of this Cabinet, I shall omit giving any farther Account of it, only taking Notice that it may be seen in a Letter to the Royal Society, of the 12th of January, 1689, and printed in his Arcana Natures Detecta, №. 69. But I was willing to mention just so much, as it may serve to shew the universal Use of these Microscopes, and as it induces me (among other Things) to believe, these were the Kind of Microscopes generally, if not solely, üs’d by this curious Gentleman in all his Observations, and to which we are oblig’d for his most surprizing Discoveries.