all so well considered and then
executed in masonry, that there is nothing to be seen by the eyes of
one who has knowledge and understanding that is more pleasing, more
beautiful, or wrought with greater mastery, both on account of the
binding together and mortising of the stones and because it has in it
in every part strength and eternal life, and also because of the great
judgment wherewith he contrived to carry away the rain-water by many
hidden channels, and, finally, because he brought it to such
perfection, that all other fabrics that have been built and seen up to
the present day appear as nothing in comparison with the grandeur of
this one. And it has been a very great loss that those whose duty it
was did not put all their power into the undertaking, for the reason
that, before death took away from us that rare man, we should have
seen that beautiful and terrible structure already raised.

Up to this point has Michelagnolo carried the masonry of the work; and
it only remains to make a beginning with the vaulting of the tribune,
of which, since the model has come down to us, we shall proceed to
describe the design that he has left to the end that it may be carried
out. He turned the curve of this vault on three points that make a
triangle, in this manner:

A B
C

The point C, which is the lowest, is the principal one, wherewith he
turned the first half-circle of the tribune, with which he gave the
form, height and breadth of this vault, which he ordered to be built
entirely of bricks well baked and fired, laid herring-bone fashion.
This shell he makes four palms and a half thick, and as thick at the
top as at the foot, and leaving beside it, in the centre, a space four
palms and a half wide at the foot, which is to serve for the ascent of
the stairs that are to lead to the lantern, rising from the platform
of the cornice where there are balusters. The arch of the interior of
the other shell, which is to be wider at the foot and narrower at the
top, is turned on the point marked B, and the thickness of the shell
at the foot is four palms and a half. And the last arch, which is to
be turned in order to make the exterior of the cupola, wider at the
foot and narrowing towards the top, is to be raised on the point
marked A, which arch turned, there remains at the top all the hollow
space of the interior for the ascent of the stairs, which are eight
palms high, so that one may climb them upright; and the thic