TELESCOPY • FREE TRANSLATOR.ORG • Definition of Telescopy

... Hamilton, of the Coast Range in Southern California, was completed. The lens of this instrument is thirty-six inches in diameter. Nor will the reader without reflection readily realize the enormous stride which was made in telescopy when the makers advanced from the twenty-seven-inch to the thirty-six-inch objective. Lenses are to each other in their power of collecting light and penetrating apace as the squares of their diameters, and in the extent of space explored as ...

— Notable Events of the Nineteenth Century - Great Deeds of Men and Nations and the Progress of the World • Various