De Beghinselen Der Weeghconst

De Beghinselen der Weeghconst ( "The Principles of the Art of Weighing") is a book about statics written by the Flemish physicist Simon Stevin in Dutch. It was published in 1586 in a single volume with De Weeghdaet ( "The Act of Weighing"), De Beghinselen des Waterwichts ("The Principles of Hydrostatics") and an Anhang (an appendix). In 1605, there was another edition.

Importance
The importance of the book was summarized by the Encyclopædia Britannica:

"In De Beghinselen der Weeghconst (1586; “Statics and Hydrostatics”) Stevin published the theorem of the triangle of forces. The knowledge of this triangle of forces, equivalent to the parallelogram diagram of forces, gave a new impetus to the study of statics, which had previously been founded on the theory of the lever. He also discovered that the downward pressure of a liquid is independent of the shape of its vessel and depends only on its height and base."

Contents
The first part consists of two books, together account for 95 pages, here divided into 10 pieces.

Book I
Start: panegyrics, Mission to Rudolf II, Uytspraeck Vande Weerdicheyt of Duytsche Tael, Cortbegryp Bepalinghen and Begheerten (definitions and assumptions)
 * Proposal 1 t / m 4: hefboomwet
 * Proposal 5 t / m 12: a balance with weights pilaer
 * Proposition 13 t / m 18: follow-up, with hefwicht, two supports
 * Proposition 19: balance on an inclined plane, with cloot Crans
 * Proposal 20 t / m 28: pilaer with scheefwichten, hanging, body

Book II

 * Proposal 1 t / m 6: center of gravity boards – triangle, rectilinear flat
 * Proposal 7 t / m 13: trapezium, divide, cut fire
 * Proposition 14 t / m 24: center of gravity of bodies – pillar, pyramid, burner
 * The Weeghdaet
 * The Beghinselen des Waterwichts
 * Anhang
 * Byvough