he mancr of the Ancients to divide the day intotwcluccquall houres, and the night into tweluc other e-qual hourcs,and fo the whele day and night into 24 houres.Of thefe *4,thofe which belonged vnto the day,wcre eitherlinger or morter (excepting the two equinoctial dayes) thenthofe which belonged… … vnequdff pmmrtt htmtu : i $% To exprefle thcfc in the former Planes : firft draw thecommon houre-lincs, the equator, and the tropiqucs,as be-fore : then defcribc two occult parallels of the length of theday, one for 9 houres,the other for 1 $ houresjfor fo you maydraw a ftreight line for the firft…
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![An illustration from L'optique divisée en trois livres : ou, l'On démontre d'une maniere aisée tout ce qui regarde 1. la propagation & les proprietez de la lumiere. 2. La vision. 3. La figure & la disposition des verres qui servent à la perfefectionner [sic] (1682)](https://img.insideoutlibrary.com/img/200/ia-loptiquedivise00ango-77-8.webp)
