apochromatic

Updated: May 11, 2025

With the present compound Microscope, only developed in the last hundred years, and its apochromatic lenses, invented only in the last forty years, we are able to see and photograph objects of a minuteness immeasurably beyond the power of the human eye, and, with our telescopes, we can see and photograph stars far beyond the possibility of vision by the unaided eye; and yet, by the stellar spectroscope, we are actually able to examine and identify the very atoms of which that distant star is composed, or rather was composed hundreds of thousands of years ago; we can compare those atoms with the same atoms in our laboratories, and we find that, though the former are hundreds of thousands of years older than the latter, they show absolutely no signs of wear or loss of energy, though they have been for that enormous time, and are still, pulsating at the rate of not only millions but billions of times per second; and though the pulsations they emit have travelled across such a vast depth of space that the mind cannot even imagine the distance, there has not been any diminution in the numbers of pulsations per second, nor the slightest slowing down of the rate of flight at which they started on their journey from that far-off world.

Sydney T. Klein - Science and the Infinite: or Through a Window in the Blank Wall