Elementary arithmetic, with brief notices of its history... by Robert Potts.

4

LOGARITHMS.

published his discovery at Edinburgh in a work entitled, "Mirifici
Logarithmorum Canonis Descriptio," reserving his method of constructing the tables until he knew what the learned might think of his
invention. The work is dedicated to Prince Charles, the son of King
James. The dedication opens with the following expressive sentiment:" Seeing there is neither study nor any kind of learning that dothI
more actuate and stir up generous and heroical wits to excellent and
eminent affairs; and contrariwise that doth more deject and keep down
sottish and dull minds than the mathematics; it is no marvel that
learned and magnanimous princes in all former ages have taken great
delight in them, and that unskilful and slothful men have always
pursued them with most cruel hatred, as utter enemies to their ignorance and sluggishness." And further adds, "And therefore this
invention (I hope) will be much the more acceptable to your Highness,
as it yieldeth a more easy and speedy way of accompt. For what can
be more delightful and more excellent in any kind of learning than to
despatch honourable and profound matters exactly, readily, and without
loss of either time or labour? "
The preface of the work is interesting, being addressed to students
of the mathematics. The following copy is taken from the English
translation of Napier's work, as it contains some additions made by
the author himself:"Seeing there is nothing (right well beloved students in the
mathematickes) that is so troublesome to mathematicall practise, nor
that doth more molest and hinder calculators, than the multiplications,
divisions, square and cubical extractions of great numbers, which,
besides the tedious expense of time, are for the most part subject to
many slippery errors. I began, therefore, to consider in my minde, by
what certaine and ready art I might remove those hindrances. And
having thought upon many things to this purpose, I found at length
some excellent briefe rules to be treated of (perhaps) hereafter. But
amongst all, none more profitable than this, which, together with the
hard and tedious multiplications, divisions, and extractions of rootes,
doth also cast away from the worke itselfe, even the very numbers
themselves that are to be multiplied, divided, and resolved into rootes,
and putteth other numbers in their place, which perform as much as
they can do, only by addition and subtraction, division by two or division by three; which secret invention, being (as all other good things
are) so much the better as it shall be the more common; I thought
good heretofore to set forth in Latine for the publique use of mathematicians. But now some of our countrymen in this island well
affected to these studies, and the more publique good, procured a most
learned mathematician to translate the same into our vulgar English
tongue, who after he had finished it sent the coppy of it to me, to be
seene and considered on by myself.
" I having most willingly and gladly done the same, finde it to be
most exact and precisely conformable to my minde and the originall.
Therefore it may please you who are inclined to these studies, to
receive it from the translator with as much good will as we recoinmnend it unto you. Fare ye well."
This work contains the natural sines and the logarithms of the sines.
for every minute of the quadrant, with a description and explanation