Gnomonicks, or the art of shadows improved. Plainly set forth in the drawing of sun-dials on all sorts of planes by different methods. With the geometrical demonstrations of all the operations / By Mr. De La Hire ... Englished and illustrated with cutts. By J. Leek.

  • La Hire, Philippe de, 1640-1718
Date:
1709
Catalogue details

Licence: Public Domain Mark

Credit: Gnomonicks, or the art of shadows improved. Plainly set forth in the drawing of sun-dials on all sorts of planes by different methods. With the geometrical demonstrations of all the operations / By Mr. De La Hire ... Englished and illustrated with cutts. By J. Leek. Source: Wellcome Collection.

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    RUN Phe Prefacex. oe thereof, it feems to methatit will be very ufelefs to re-fearch into the time of. the moft ancient Antiquity, and whe was the Inventer of this Art : We may only believe, very likely that it was per- fected by little andlittle, andthat the firft Men feeing the neceflity which they had to divide the continuance of a day into divers parts, judged that it could not be better done than by the fame Suz which limits the continuance RAT D PE ici. PANNE TE) ES avr (in ; i” » a | ‘ thereof. : . We may alfo be very eafily perfwad- ed that the Meridian Line hath been the firft which they have drawn, as well becaufe that it divides the apparent day , which is the time during which _ we may fee the Suv, into two equal parts, and that the Shadow of a. Strait-line raifed perpendicularly upon an Hori- zontal Plane, was always extended a- long this Meridian Line when the top of it mects withit, although it bein dif: ferent places ; fo that it ferves us to know the greateft height of the Suz ac bove the Horizon every day, the which changes during the time of half a Year, _ Ca peter: