In the wonderful versatility of the human mind, the improvement, when
made, will very probably be made by paths where it is least expected.
The great inducement to Mr. Babbage to attempt the construction of an
engine by which astronomical tables could be calculated, and even
printed, by mechanical means and with entire accuracy, was the errors
in the requisite tables. Nineteen such errors, in point of fact, were
discovered in an edition of Taylor's Logarithms printed in 1796; some
of which might have led to the most dangerous results in calculating a
ship's place. These nineteen errors, (of which one only was an error of
the press), were pointed out in the _Nautical Almanac_ for 1832. In one
of these _errata_ the seat of the error was stated to be in cosine of
14° 18' 3". Subsequent examination showed that there was an error of one
second in this correction; and, accordingly, in the _Nautical Almanac_
of the next year a new correction was necessary. But in making the new
correction of one second, a new error was committed of ten degrees.
Instead of cosine 14° 18' 2" the correction was printed cosine 4° 18' 2"
making it still necessary, in some future edition of the _Nautical
Almanac_, to insert an _erratum_ in an _erratum_ of the _errata_ in
Taylor's logarithms.[A]
[Footnote A: Edinburgh Review, Vol. LIX., 282.]
In the hope of obviating the possibility of such errors, Mr. Babbage
projected his calculating, or, as he prefers to call it, his difference
machine. Although this extraordinary undertaking has been arrested, in
consequence of the enormous expense attending its execution, enough has
been achieved to show the mechanical possibility of constructing an
engine of this kind, and even one of far higher powers, of which Mr.
Babbage has matured the conception, devised the notation, and executed
the drawings--themselves an imperishable monument of the genius of the
author.
I happened on one occasion to be in company with this highly
distinguished man of science, whose social qualities are as pleasing as
his constructive talent is marvelous, when another eminent _savant_,
Count Strzelecki, just returned from his Oriental and Australian tour,
observed that he found among the Chinese, a great desire to know
something more of Mr. Babbage's calculating machine, and especially
whether, like their own _swampan_, it could be made to go into the
pocket. Mr. Babbage good-humouredly observed that, thus far, he had been
very much out of pocket with it.