ClipArt ETC
"Let a be the distance at which an object can be see distinctly, and b, the distance at which the same object is seen through the lens, and supose tthe distance of a from the eye, be twice that of b. Then because the object is at half the distance that it was before, it will appear twice as large...." -Comstock 1850

Single Microscope

"Let a be the distance at which an object can be see distinctly, and b, the distance at which the same…