"--H. M. Hyndman.
One of the most extraordinary things connected with Applied
Science is the method by which the Navigator is enabled to find
the exact spot of sea on which his ship rides. There may be
nothing but water and sky within his view; he may be in the midst
of the ocean, or gradually nearing the land; the curvature of the
globe baffles the search of his telescope; but if he have a
correct chronometer, and can make an astronomical observation, he
may readily ascertain his longitude, and know his approximate
position--how far he is from home, as well as from his intended
destination. He is even enabled, at some special place, to send
down his grappling-irons into the sea, and pick up an electrical
cable for examination and repair.
This is the result of a knowledge of Practical Astronomy. "Place
an astronomer," says Mr. Newcomb, "on board a ship; blindfold
him; carry him by any route to any ocean on the globe, whether
under the tropics or in one of the frigid zones; land him on the
wildest rock that can be found; remove his bandage, and give him
a chronometer regulated to Greenwich or Washington time, a
transit instrument with the proper appliances, and the necessary
books and tables, and in a single clear night he can tell his
position within a hundred yards by observations of the stars.
This, from a utilitarian point of view, is one of the most
important operations of Practical Astronomy.
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