Transcriber's note:

Several few typographical errors have been corrected. They appear in the text like this, and the explanation will appear when the mouse pointer is moved over the marked passage. Cases which could conceivably be genuine variable orthography have been retained as printed. Many corrections are actually part of the arguments: no guarantee is given that all such errors in the text have been found and corrected. In the original, 20 pages were printed with out-of-sequence page numbers, the numbers as printed being repeated in the index. These have been retained as printed but marked with an asterisk to distinguish them from the in-sequence pages which have the same number, thus 249* Mixed fractions have been consistently transcribed as e.g. 5.5/96 although the period is not always present in the printed text (this avoids possible confusion of a hyphen, as 5-5/96, with a minus sign). The plus and minus signs in the printed text are apparently indistinguishable dashes - they have been transcribed as '+' and '-' as the context requires.

VIA REGIA

GEOMETRIAM.

THE WAY

GEOMETRY.

Being necessary and usefull,

For