DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.6094#0329
30b" A TOUR THROUGH
vessels lay in a right line betwixt him and
the sun at noon; and at a very small di-
stance from the wall of the city where
this tower Rood. But if you will suppose
this to have been performed by common
burning-glasses, or by those of the para-
bolical kind, it will be necessary to raise a
tower of a raost enormous height on the
issahd of Ortigia, in order to interpose
these glasses betwixt the sun and the Ro-
man galleys; and even this could not have
been done till late in the afternoon, when
his rays are exceedingly weak. But I have
very little doubt that common looking-
glasses would be found all-suffkient to per-
form these esfects.
Let us suppose that a thousand of these
were made to ressedT: the rays to the
same point: The heat, in all probability,
must be increased to a greater degree than
in the focus of most burning-glasses; and
abun-
vessels lay in a right line betwixt him and
the sun at noon; and at a very small di-
stance from the wall of the city where
this tower Rood. But if you will suppose
this to have been performed by common
burning-glasses, or by those of the para-
bolical kind, it will be necessary to raise a
tower of a raost enormous height on the
issahd of Ortigia, in order to interpose
these glasses betwixt the sun and the Ro-
man galleys; and even this could not have
been done till late in the afternoon, when
his rays are exceedingly weak. But I have
very little doubt that common looking-
glasses would be found all-suffkient to per-
form these esfects.
Let us suppose that a thousand of these
were made to ressedT: the rays to the
same point: The heat, in all probability,
must be increased to a greater degree than
in the focus of most burning-glasses; and
abun-