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. LIX. How to make an instrument to helpe hea∣ring, as Gallileus made to helpe the sight.

THinke not that the Mathematickes (which hath furnished us with such admirable helpes for seeing) is wanting for that of hearing: its well knowne that long trunkes or pipes makes one heare well farre off, and experi∣ence shewes us that in certaine places of the Arcades in a hollow vault, that a man speaking but softly at one corner thereof, may be audi∣bly understood at the other end: notwithstan∣ding these which are betweene the parties can∣not heare him speake at all: And it is a generall principle, that pipes doe greatly helpe to strengthen the activitie of naturall causes: we see that fire contracted in a pipe, burnes 4. or 5. foot high, which would scarce heat, being in the open aire: the rupture or violence of water issu∣ing out of a fountaine, shewes us that water be∣ing contracted into a pipe, causeth a violence in its passage. The Glasses of Gallileus makes us

see how usefull pipes or trunkes are to make the light and species more visible, and propor∣tionable to our eye. It is said that a Prince of Italy hath a faire hall, in which he can with fa∣cility heare distinctly the discourses of these which walke in the adjacent gardens, which is by certaine vessels and pipes that answere from the garden to the hall. Vitruvius makes mention also of such vessels and pipes, to strengthen the voyce and action of Comedians: and in these times amongst many noble personages, the new kinde of trunkes are used to helpe the hearing, being made of silver, copper, or other resounding materiall; in funnell-wise putting the widest end to him which speaketh, to the end to contract the voyce, that so by the pipe applyed to the eare it may be more uniforme and lesse in dan∣ger to dissipate the voyce, and so consequent∣ly more fortified.