1816.] Royal Institute of France. 141 
different systems proposed by philosophers respecting the ancient 
state of the different seas which at present compose the Medi- 
terraneans This is all that it is possible to say at present of a 
work merely known to us by a single reading. 
M. Rochon, who has supplied astronomers with a more exact 
method of estimating the diameters of the little planets, has stated 
to the Class his ideas about extending that method to the diameters 
of the sun and moon. 
M. le Chevalier Delambre has given the description of a sun-dial 
found at Delos among the ruins of the temple of Apollo, which 
was brought to Paris by M. Mauduit, jun. architect in the service 
of the Emperor of Russia, and deposited in the Cabinet of Anti- 
guities. ‘I'he author of the memoir has taken occasion to treat of 
the gnomonics of the ancients. 
Just when this article was going to press, we were informed that 
the Antiquities of Athens by Stuart, newly translated into French, 
Paris, Firmin Didot, 1808, contains a gnomonic monument much 
more important, more curious, and especially more compiete. We 
have read in the dissertation of Martini, p. 60, that Leroi in his 
Ruins of the Monuments of Ancient Greece, p. 15, has described 
a dial which he had seen at Athens, near the house of Thra- 
sillus. | Martini adds, that his dial is quite similar to that of 
Berosus. He says, likewise, that the figure which Leroi has given 
of itis very incomplete. This prevented us from consulting Leroi, 
and led us to conclude that Athens offered nothing of this kind 
worthy of exciting our curiosity. By the advice of M. Visconti, 
we have consulted the work of Stuart. We there find a very de- 
tailed description of a monument known by the name of the ‘Tower 
of the Winds. It isa regular octagon, on the faces of which are 
represented the eight principal winds, below which are seen eight 
different dials, four regular and four declining, at angles of 
45°, 135°, 225°, and 315°. The regular dials are the verticals 
of south, north, east, west ; the four others are in the intermediate 
positions. 
Vitruvius, who has described this Tower of the Winds in the 
sixth chapter of his first book, does not say a word about these eight 
dials: and, what is singalar is, that in the part of his book in 
which he speaks of all the known dials, he keeps the same 
silence with respect to the eight dials of Athens, though more 
important in every respect than those of which he names the in- 
ventors. One seems entitled to conclude from this, that the 
dials have been added afterwards at a time posterior to Vitru- 
vius, and especially posterior to the time of Andronicus Cyrrhestes, 
author of the monument. 
Stuart, who makes himself this objection, endeavours to answer 
it by a passage of Varro, who, speaking of this tower, denotes it by 
the name of the Tower of the Clock, This answer, which is far 
from direct, becomes still less so by the efforts which Stuart makes 
. 
