land. When the time came that the government, through its courts,
punished the breach of a custom, from that time the custom was a law. And
so the English people acquired these laws, one after another, just as they
were acquiring at the same time the habits of making roads, using forks at
table, manufacturing, meeting in Parliament, using firearms, and all the
other habits of civilization. When the colonists came to America, they
brought the English Common Law with them, not in a book, but in their
minds, a part of their life, like their religion.

--Clark: _The Government_.

3. Accuracy is always to be striven for but it can never be attained. This
fact is only fully realized by scientific workers. The banker can be
accurate because he only counts or weighs masses of metal which he assumes
to be exactly equal. The Master of the Mint knows that two coins are never
exactly equal in weight, although he strives by improving machinery and
processes to make the differences as small as possible. When the utmost
care is taken, the finest balances which have been constructed can weigh 1
lb. of a metal with an uncertainty less than the hundredth part of a
grain. In other words, the weight is not accurate, but the inaccuracy is
very small. No person is so stupid as not to feel sure that the height of
a man he sees is between 3 ft. and 9 ft.; some are able by the eye to
estimate the height as between 5 ft. 6 in. and 5 ft. 8 in.; measurement
may show it to be between 5 ft. 6 in. and 5 ft. 7 in., but to go closer
than that requires many precautions. Training in observation and the use
of delicate instruments thus narrow the limits of approximation. Similarly
with regard to space and time, there are instruments with which one
millionth of an inch, or of a second, can be measured, but even this
approximation, although far closer than is ever practically necessary, is
not accuracy. In the statement of measurements there is no meaning in more
than six significant figures, and only the most careful observations can
be trusted so far. The height of Mount Everest is given as 29,002 feet;
but here the fifth figure is meaningless, the height of that mountain not
being known so accurately that two feet more or less would be detected.
Similarly, the radius of the earth is sometimes given as 3963.295833
miles, whereas no observation can get nearer the truth than 3963.30 miles.

--Mill: _The Realm of Nature_. (Copyright, 1892, by Charles Scrib