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. INCREASED COMMAND OF INSTRUMENTAL POWER.