rays falling on earth from a flight of a hundred years, are as sounding
lines dropped in the appalling depths of space. We wish to describe a
few of these intricate instruments, and mention several far-reaching
discoveries made by their use; beginning with mechanism for the
manipulation of light. Optics is based on the accidental discovery that
a piece of glass of certain shape will draw light to a focus, forming an
image of any object at that point. The next step was in learning that
this image can be viewed with a microscope, and magnified; thus came the
telescope revealing unheard of suns and galaxies. The first telescopes
colored everything looked at, but by a hundred years of mathematical
research, the proper curvature of objectives formed of two glasses was
discovered, so that now we have perfect instruments. Great results
followed; one can now peer into the profound solitudes of space,
bringing to view millions of stars, requiring light 5,000 years to
traverse their awful distance, and behold suns wheeling around suns, and
thousands of nebulae, or agglomerations of stars so distant as to send
us confused light, appearing like faint gauze like structures in
measureless voids. The modern telescope has astonishing power, thus:
When Mr. Clark finished the great twenty-six-inch equatorial, now at
Washington, he tested its seeing properties. A photographic calligraph,
whose letters were so fine as to require a microscope to see them, was
placed at a distance of three hundred feet. Mr. Clark turned the great
eye upon the invisible thing and read the writing with ease. But a
greater feat than this was accomplished by the same instrument-- the
discovery of the two little moons of Mars, by Prof. Asaph Hall, in 1877.
They are so small as to be incapable of measurement by ordinary means,
but with an ingenious photometer devised by Prof. Pickering of Harvard
College, he determined the outer satellite to be six and the inner seven
miles in diameter. The discovery of these minute bodies seems past
belief, and will appear more so, when it is told that the task is equal