130 Description and Use of the

are graduated, in two concentric spaces, themonths and days of the year.

Bring the day of the month to coincidewith the broad paper circle, and the terres-trial globe is rectified.

When the globe is thus rectified, thatdegree and minute upon the graduated sideof the brass meridian, which is then cutby the plane of the broad paper circle, isthe distance of the shade of extuberancyupon the earth’s disc, reckoned from thepole, and is equal to the fun’s declinationfor that day ; and is therefore also equal tothe latitude, counted from the equator, of allthose places to which the fun is verticaland this point on the brass meridian repre-sents the central solar ray describing theparallel of the day.

If now the globe be turned from west:to east, all those places which arrive atthe western edge of the broad paper circle,are pasting out of the twilight into the fun’slight; and the fun then appears rising toall the inhabitants.

At the fame time, if you look upon theeastern edge of the broad paper circle, itwill cut all those places which are then

passing