12. Baillie, _Histoire de l'Astronomie_.

13. Delambre[1], _Hist. de l'Astr. du moyen age_.

14. Hutton's _Tracts_ (8vo. ed. 1812.), vol. ii. (subject "History of
Algebra")

15. Huet, _Demonstratio Evangelica_.

16. Dr. John Taylor's Translation of the _Lilawati_. (Bombay, 1816.)

17. Strachey's Translation of the _Bija Ganita_[2].

18. Colebrooke's _Algebra of the Hindus_.

Would it not be worth while to give a _facsimile_ of the "Tabel for
all manere of merchauntes," in the "Notes and Queries"? It is not only
a curiosity, but an important element (and unique as far as is known)
in the philosophic history of our arithmetic. It was, no doubt, an
actual instrument in constant use in the merchant's office, as much so
as an almanac, interest-tables, a "cambist" and a copying-press, are
now.

As regards the cipher, the difficulty only commenced with _writing
numbers_ in the new symbology. With persons accustomed to the use
of this instrument, there is no doubt that the mode of obviating the
difficulty of "keeping the place," would suggest itself at once. In
this instrument an empty hole (without its peg) _signified_ "none of
this denomination." What then more simple than to make the outline
of the empty hole which occupied the "local position" of any