IN my Youth-hood I was employed in Clerkship under, and received some
Mathematical Knowledge from Mr.
John Marr, one of the Clerks of the
Kitchin to His Present MAJESTY, when
PRINCE of
WALES, the said Mr.
Marr being very Eminent for his
Mathematical Knowledge, some testimony whereof may be evinced, from those excellent
Dyals, wherewith the Gardens of our Late
SOVERAIGN were adorned.
Our Intestine Miseries increasing, I lost that Employment, and went Seven Years to Sea, most part of it in an
English Merchant-man, become a Man of War in the
Venetian Service against the
Turks, in which having leisure, I applied part of my Studies to
Mathematicks and
Merchants-Accompts, and upon my Return fell to the Practice thereof, and afterwards profest
Writing, Merchants-Accompts, and some Parts of the
Mathematicks; and having drawn up some Books of Accompts, and divers loose Questions, for the Instruction of my Scholars, in the Years
1652 I committed them to the Press, under the Name of
An Introduction to Merchants-Accompts; they were again Reprinted in the Year
1664/5, without alteration; and in
1666, the Fire consumed the greatest part of the Impression: The
Stationer hath since often urged me to alter and enlarge the same for another
Edition, presuming, that I that have been much and lately concerned in great and Publick
Accompts, and have studied and been employed in the Affairs of Publick Trade and Plantations, might alter the same to good advantage, and perchance others may be of the same mind; but I concur not, finding that my said long Experience hath not at all advanced my Knowledge in good Methods of
Accompts, though I confess I understand the nature and Intrigues of bad ones much better than I did. Whereupon I have consented, and
[Page]advised the
Stationer to Reprint the same with the Addition of two more
Accompts than were formerly extant, and was the more willing to do it at this time for this Reason, namely:
That I might take the opportunity of acquainting those who are, or may be concerned, That I spend part of my time in Stating
Merchants-Accompts, Ship-Accompts, or any Controversal Intricate
Accompts, (concerning which, as some have, so more may become Suits in
Chancery or
Equity, commenced or depending;) and in Computing of
Interest, the Variation or Forbearance of
Leases, Mortgages, and
Annuities; and am to be heard of at Mr.
Robert Horn's the
Stationer, at the South-Entrance of the
Royal Exchange, for whom this Book was Printed.
And now as to the ensuing Work, I have this to say, That when I first Composed it, I observed a want of such Questions, that might not tire out the patience of the
Reader or
Student, there being none but
Journals and
Leidgers of other Authors in Print, seeming to some like a Labyrinth of a more than sufficient length, and the which, when traced through, might possibly leave the Reader unskilful in these shorter Questions; some whereof have had their rise from real Affairs, which have happened much of the same kind. And now if the Reader be still unexperienced, and desirous to reap some benefit thereby, let me advise him to write out the
Journals of some of these
Accompts, omitting the Relative Numbers in the Margin, of the which see
Section the seventh following, and are not to be made till the Parcel is entirely Posted, which that he may be enabled to do, he may use the ensuing Directions; but if this be thought too laborious, he may prick and examin over the said
Questions, the
Accompt it self gives Instruction for
Ballancing, the
Ballance of each
Accompt, being Entred out of the
Leidger at the end of the
Journal Parcels.
Divers
Accomptants have made the Business of
Simple and
Compound Interest, and
Annuities, the Subject of their Discourses: And I think it not improper to tell the Reader, that in
1664 I published a Paper, consisting of a quarter of a Sheet, and fitted for a Letter-Case, Intituled,
The Doctrin of Decimal Arithmetick, Simple Interest, &c. as also of
Compound Interest, and
Annuities, generally performed for any time of Payment or Rate of
Interest, by help of any particular Table of the forbearance of One Pound Principal.
The which having been censured by some that understood it not, I think it not amiss, a little better to inform them, That the Table therein used, is a Table of
Compound Interest, at
6 per Centum per Annum, for some Days, as well as (it is usual) for some Years, the which to the said, or any other
Ratio, may be raised by several Methods, without any Extractions of
Roots, or Aid of
Logarithms; yea any
Logarithm in the
Canon may be easily computed thereby, and the Converse; also any Number of
Mean Proportionals found between two Extreams given.
The which Table and Precepts, removing the necessity of using a large Table of
Logarithms, or of those multitudes of Tables, fitted for the several kinds of
Annuity Problems, at several Rates of
Interest, and several Terms
[Page]of Payment, having been of constant and singular use to my self, and believing it will be of no less to others, I intend (God willing) to Reprint, to be fitted as before, to be a
Vade-mecum in a Letter-Case, though with a larger Table, (which will remove some Operations hitherto necessary, to supply the want thereof) and besides an Explication thereof apart, illustrated with variety of Examples: And hope also hereafter to have some time to alter, amend, and Reprint other Treatises of my own, as my Book of
Quadrants and
Dyalling, but most especially my Treatise of
Navigation, Intituled,
The Mariners Plain Scale new plained; the rather, in regard His present Majesty, to His Immortal Praise, hath been pleased to settle a Maintenance for Forty
Hospital Boys, and for a Learned
Lecturer to teach them
Navigation; on the Advancement whereof, the Splendor of the Government, and the Trade and Safety of this Nation doth so much depend, that any that love their Country cannot but be zealous for, as particularly is,
Thy Friend and Well-wisher,
JOHN COLLINS.