in, here, diuerse compoundyng of Numbers: as some
tyme, two, three, foure (or more) _Radicall_ numbers, diuersly knit, by
signes, of More & Lesse: as thus [2rt]12 + [3rt]15. Or thus [4rt]19 +
[3rt]12 - [2rt]2. &c. And some tyme with whole numbers, or fractions of
whole Number, among them: as 20 + [2rt]24. [3rt]16 + 33 - [2rt]10.
[4rt]44 + 12-1/4 + [3rt]9. And so, infinitely, may hap the varietie.
After this: Both the one and the other hath fractions incident: and so
is this _Arithmetike_ greately enlarged, by diuerse exhibityng and vse
of Compositions and mixtynges. Consider how, I (beyng desirous to
deliuer the student from error and Cauillation) do giue to this
_Practise_, the name of the _Arithmetike of Radicall numbers_: Not, of
_Irrationall_ or _Surd Numbers_: which other while, are Rationall:
though they haue the Signe of a Rote before them, which, _Arithmetike_
of whole Numbers most vsuall, would say they had no such Roote: and so
account them _Surd Numbers_: which, generally spoken, is vntrue: as
_Euclides_ tenth booke may teach you. Therfore to call them, generally,
_Radicall Numbers_, (by reason of the signe [rt]. prefixed,) is a sure
way: and a sufficient generall distinction from all other ordryng and
vsing of Numbers: And yet (beside all this) Consider: the infinite
desire of knowledge, and incredible power of mans Search and Capacitye:
how, they, ioyntly haue waded farder (by mixtyng of speculation and
practise) and haue found out, and atteyned to the very chief perfection
(almost) of _Numbers_ Practicall vse. Which thing, is well to be
perceiued in that great Arithmeticall Arte of _Aequation_: commonly
called the _Rule of Coss._ or _Algebra_. The Latines termed it, _Regulam
Rei & Census_, that is, the +_Rule of the thyng and his value_+. With an
apt name: comprehendyng the first and last pointes of the worke. And the
vulgar names, both in Italian, Frenche and Spanish, depend (in namyng
it,) vpon the signification of the Latin word, _Res_: +_A thing_+:
vnleast they vse the name of _Algebra_. And therin (commonly) is a
dubble error. The one, of them, which thinke it to be of _Geber_ his
inuentyng: the other of such as call it _Algebra_. For, first, though
_Geber_ for his great skill in Numbers, Geometry, Astronomy, and other
maruailous Artes, mought haue semed hable to haue first deuised the sayd
Rule: and also the name carryeth with it a very nere likenes of _Geber_
his name: yet true it is, that a _Greke_ P