I, where the line drawn through the centre
at the point A cuts the circumference; opposite G and H will be the
points L and K; and opposite C, F, and A will be the point N.

5. Then, diameters are to be drawn from G to L and from H to K. The
upper will denote the summer and the lower the winter portion. These
diameters are to be divided equally in the middle at the points M and O,
and those centres marked; then, through these marks and the centre A,
draw a line extending to the two sides of the circumference at the
points P and Q. This will be a line perpendicular to the equinoctial
ray, and it is called in mathematical figures the axis. From these same
centres open the compasses to the ends of the diameters, and describe
semicircles, one of which will be for summer and the other for winter.

6. Then, at the points at which the parallel lines cut the line called
the horizon, the letter S is to be on the right and the letter V on the
left, and from the extremity of the semicircle, at the point G, draw a
line parallel to the axis, extending to the left-hand semicircle at the
point H. This parallel line is called the Logotomus. Then, centre the
compasses at the point where the equinoctial ray cuts that line, at the
letter D, and open them to the point where the summer ray cuts the
circumference at the letter H. From the equinoctial centre, with a
radius extending to the summer ray, describe the circumference of the
circle of the months, which is called Menaeus. Thus we shall have the
figure of the analemma.

7. This having been drawn and completed, the scheme of hours is next to
be drawn on the baseplates from the analemma, according to the winter
lines, or those of summer, or the equinoxes, or the months, and thus
many different kinds of dials may be laid down and drawn by this
ingenious method. But the result of all these shapes and designs is in
one respect the same: namely, the days of the equinoxes and of the
winter and summer solstices are always divided into twelve equal parts.
Omitting details, therefore,--not for fear of the trouble, but lest I
should prove tiresome by writing too much,--I will state by whom the
different classes and designs of dials have been invented. For I cannot
invent new kinds myself at this late day, nor do I think that I ought to
display the inventions of others as my own. Hence, I will mention those
that have come down to us, and by whom they were invented.

CHAPTER VIII

SUNDI