The circles of proportion and the horizontal instrument. The former shewing the maner how to work proportions both simple and compound: and the ready and easy resolving of quæstions both in arithmetic, geometrie, & astronomie: and is newly increased with an additament for navigation. All which rules may also be wrought with the penne by arithmetic, and the canon of triangles. The later teaching how to work most quæstions, which may be performed by the globe: and to delineat dialls upon any kind of plaine. Invented, and written in latine by W.O. Translated into English, and set out for the public benefit, by William Forster.

The Translator to the Reader.

Gentle Reader, by reason of my absence, whilest this Booke was in the Presse, it is no meruaile though some faults haue escaped, which you will be pleased to amend thus.

Pag. 14 lin. 14, 2.0413927. Pag. 15. lin. 1, the first terme of a progression Pag. 17, lin 17, the Antecedent arme Pag. 18 lin. 19, terme giuen from Pag. 19 lin. 11, in the fift circle Pag. 20 lin. 19, lye hid. As in this lin. 20 D. Rat. mul^ta—1 in R. lin. 28, and Rat mul^ta in R in α—R in α,

Also in the aequations pag. 21, 24, 26 which haue a magni∣tude equall to a fraction: the same magnitude together with the note of equality, ought to be set right against the line that is betweene the Numerator and Denominator of the fraction, as in these, 〈 math 〉〈 math 〉. And 〈 math 〉〈 math 〉. And so of the rest.

Pag. 25 lin. 20, arme at 71⌊382: Pag. 26 lin. 16, Ratioci∣nation. Pag. 29 lin. 29. number of figures Pag. 35 lin. 5, 61 49/144 Pag. 36 lin. 11, 17⌊48 lin. 14, 17⌊48 · 3⌊26 +. Pag. 44 lin. 8, is a roofe line 26, therof Pag. 94 lin. 21, a circle, or 90 degrees. Pag. 100 lin. 3, and then the side DC Pag. 113 lin. 7, delineation Pag. 127 lin. 1, the Sunne goeth not Pag. 131 lin. 19, in the paper Pag. 132 lin. 10, to the tangent of the arch of Pag. 143 lin. 3, in North reclining, and South inclining Pag. 152 lin. 30 North Dyall declining Eastward 35 deg.