The construction of the wonderful canon of logarithms

Construction of the Canon. 43
logarithm is required. The complement of the
half arc is 55 degrees 20 minutes, and its logarithm
1954370 is given. Wherefore add 6931469
to 665143, making 7596612, subtract 1954370,
and there remains 5642242, the required logarithm
of an arc of 34 degrees 40 minutes.
58. When the logarithms ofall arcs not less than 45 degrees
are given, the logarithms of all less arcs are very easily
obtained.
From the logarithms of all arcs not less than 45
degrees, given by hypothesis, you can obtain (by
57) the logarithms of all the remaining arcs decreasing
down to 22 degrees 30 minutes. From
these, again, may be had in like manner the logarithms
of arcs down to 11 degrees 15 minutes.
And from these the logarithms of arcs down to
5 degrees 38 minutes. And so on, successively,
down to I minute.
59. To form a logarithmic table.
Prepare forty-five pages, somewhat long in
shape, so that besides margins at the top and
bottom, they may hold sixty lines of figures.
Divide each page into twenty equal spaces by
horizontal lines, so that each space may hold three
lines of figures. Then divide each page into
seven columns by vertical lines, double lines being
ruled between the second and third columns and
between the fifth and sixth, but a single line only
between the others.
Next write on the first page, at the top to the
left, over the first three columns, "o degrees";
and at the bottom to the right, under the last
F 2 three