474 Scientific Proceedings, Royal Dublin Society. 
light which Sir Robert examined and commended, and I hope to 
show him this new improvement. 
The great economy which attends the use of this light—a 
matter of great importance in the eyes of lighthouse authorities— 
may be seen from the fact that it is produced at the cost of half 
a pint of petroleum per hour, say about one halfpenny per 
hour, very much less than any other light of similar power yet 
introduced. 
The light shown is of 1000 candle power. I am having a 
burner made which I believe will give four times that power, 
and so small is its cost that this great power may be applied 
constantly, and not only as the state of the weather requires it, 
as in the present gas and oil system, thus making the sailor 
independent of the lightkeeper’s observation of the weather. Of 
course these high candle powers to which I refer are those of the 
light only, and are quite independent of the great assistance 
which the lenticular apparatus gives to it in its transmission to 
the horizon. 
It is one of the advantages of this system that it can be 
applied in districts and places where it is almost, if not altogether, 
impossible to obtain gas light or electric light. Its portability is 
another of its peculiarities. Although it is, as has been said, 
essentially a gas light, yet the gas-making apparatus which is 
necessary to produce it is truly portable and vastly simpler and 
smaller in compass than any ordinary gas-making apparatus. It 
is the small space which it requires which renders this kind of 
light peculiarly suitable for isolated positions, such as rock light- 
houses, beacons, and lightships. 
The paper was illustrated by an exhibition of the new light as 
a lighthouse light in the focus of a first order dioptric apparatus, 
and also as asky-flashing light. Afterwards the light was allowed 
to illuminate the Lecture Theatre. | 
