What are the great wonders, the great sources of man’s material
strength, wealth, and comfort in modern times? The Railway, with its
mile-long trains of men and merchandise, moving with the velocity of
the wind, and darting over chasms a thousand feet wide; the Electric
Telegraph, along which man’s thoughts travel with the velocity of
light, and girdle the earth more quickly than Puck’s promise to his
master; the contrivance by which the Magnet, in the very middle of
a strip of iron, is still true to the distant pole, and remains a
faithful guide to the mariner; the Electrotype process, by which a
metallic model of any given object, unerringly exact, grows into
being like a flower. Now, all these wonders are the result of recent
and profound discoveries in theoretical science. The Locomotive
Steam-engine, and the Steam-engine in all its other wonderful and
invaluable applications, derives its efficacy from the discoveries, by
Watt and others, of the laws of steam. The Railway Bridge is not made
strong by mere accumulation of materials, but by the most exact and
careful scientific examination of the means of giving the requisite
strength to every part, as in the great example of Mr. Stephenson’s
Britannia Bridge over the Menai Strait. The Correction of the Magnetic
Needle in iron ships it would have been impossible for Mr. Airy to
secure without a complete theoretical knowledge of the laws of
Magnetism. The Electric Telegraph and the Electrotype process include
in their principles and mechanism the most complete and subtle results
of electrical and magnetical theory.--_Edinburgh Review_, No. 216.