350 Scientific Proceedings, Royal Dublin Society. 
will soon find their way into the general lighthouse systems, not — 
only of the United Kingdom, but also of other countries. 
The Paper was illustrated by the exhibition of a “fixed light” 
dioptric apparatus with a Wigham gas-burner lighted in its focus, 
also a group of annular lenses, the focal light of which was similar 
to that at Tory Island lighthouse. The light of this group was 
automatically cut off and restored by the machine which rotated 
the lenses. 
