In 1784, M. Æpinus published a description of what he termed new-invented microscopes, in a letter to the Academy of Sciences at Petersburgh;[22] they are nothing more than an application of the achromatic perspective to microscopic purposes. Now it has been long known to every one who is the least versed in optics, that any telescope is easily converted into a microscope, by removing the object glass to a greater distance from the eye glasses; and that the distance of the image varies with the distance of the object from the focus, and is magnified more as its distance from the object is greater: the same telescope may, therefore be successively turned into a microscope, with different magnifying powers. Mr. Martin had also shewn, in his description and use of a polydynamic microscope, how easily the small achromatic perspective may be applied to this purpose. Botanists might find some advantage in attending to this instrument; it would assist them in discovering small plants at a distance, and thus often save them from the thorns of the hedge, and the dirt of a ditch. [22] Description des Nouveaux Microscopes inventes par M. Æpinus. Fig. 1. Plate III, represents the improved lucernal microscope. Fig. 1. Plate IV. The improved compound and single microscope. Fig. 2. Plate IV. The best universal compound microscope. Fig. 3. Plate IV, is what is usually called Culpeper’s, or the common three pillared compound microscope. Fig. 1. Plate V, represents Martin’s solar opake microscope. Fig. 4. Plate VI, is a picture of the common solar microscope. Fig. 1. Plate VII. A, is Cuff’s common compound microscope. Fig. 3. Plate VIII. Martin’s new microscopic telescope, or convenient portable apparatus for a traveller. We cannot conclude this chapter better than with the following observations on the microscope. We are indebted to it for many discoveries in natural history; but let us not suppose that the Creator intended to hide these objects from our observation. It is true, this instrument discovers to us as it were a new creation, new series of animals, new forests of vegetables; but he who gave being to these, gave us an understanding capable of inventing means to assist our organs in the discovery of their hidden beauties. He gave us eyes adapted to enlarge our ideas, and capable of comprehending a universe at one view, and consequently incapable of discerning those minute beings, with which he has peopled every atom of the universe. But then he gave properties and qualities to matter of a particular kind, by which it would procure us this advantage, and at the same time elevated the understanding from one degree of knowledge to another, till it was able to discover these assistances for our sight.