Mathematicall recreations. Or a collection of sundrie problemes, extracted out of the ancient and moderne philosophers, as secrets in nature, and experiments in arithmeticke, geometrie, cosmographie, horolographie, astronomie, navigation, musicke, opticks, architecture, staticke, machanicks, chimestrie, waterworkes, fireworks, &c. ... Most of which were written first in Greeke and Latine, lately compiled in French, by Henry Van Etten Gent. And now delivered in the English tongue, with the examinations, corrections, and augmentations.

PROBLEM. VI. ••w three staves, knives, or like bodies may be conceaved to hang in the Aire, without being supported by any thing, but by themselves.

TAke the first staffe A. B. raise up in the Aire, the end B. and upon him croswise ••ce the staffe C. B. then lastly in Triangle wise ••ce the third staffe E.F. in such manner that may be under A. B. and yet upon C. D. I 〈◊〉〈◊〉 that these staves so disposed cannot fall, and

the space C. B. E. is made the stronger, 〈◊〉〈◊〉 how much the more it is pressed downe, if th•• staves breake not, or sever themselves fro•• the triangular forme▪

[illustration] diagram

so that alwayes the Center of gravitie be in the Center of the Triangle: for A. B. is supported by E. F. and E. F. is helde up by C. D. and C. D. is kept up from falling by A. B therefore one of these staves can∣not fall, and so by consequence none.