[ 90 ]
TOC
|
of the party; I gladly accepted the pro-
posal, and he immediately began to shew
and explain to me the construction and
use of several machines and contrivances
which he had invented for making opti-
cal experiments, before the arrival of
the Signori, who were a Knight of Malta,
a nephew of Pope Benedict XIV. and
another Cavaliere.
He then went on, and surprised and
delighted us all very much, particularly
with his Stet Sol, by which he can fix
the sun's rays, passing through an aper-
ture or a prism, to any part of the oppo-
site wall he pleases: he likewise sepa-
rates and fixes any of the prismatic co-
lours of the rays. Shewed us a method
of forming an aquatic prism, and the ef-
fects of joining different lenses, all ex-
tremely plain and ingenious. He has
published a Latin dissertation on these
matters at Vienna. Then we ascended
to different observatories, where I found
his instruments mounted in so ingeni-
|
.jpg)