“The inferiority of the human sense organ to the instruments of
science is pointed out by Dr. Carl Snyder,” says _The American
Inventor_. “He says that whereas the human eye can see but
little more than 3,000 stars in the heaven on the clearest of
nights, the photographic plate and the telescope can discover
countless millions. It is difficult for the eye to distinguish
divisions of the inch if smaller than 1-200 of that unit of
measure, yet a powerful microscope will make an object 1-1,000
of an inch in diameter look comparatively large. It would be
a delicate ear which could hear the tramp of a fly, yet the
microphone magnifies this sound until it sounds like the tramp
of cavalry. The most sensitive skin can not detect a change in
temperature less than 1-5 of a degree, but the bolometer will
register on a scale an increase or decrease of temperature of
1-1,000,000 of a degree and can easily note the difference in
temperature caused in a room when a match is lighted one mile
away.”
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