i a 
WicHam—ZIJmprovements in Buoy Lamps and Beacons. mae 
ordinary coal gas, when compressed, loses its illuminating power 
toa great extent; special plant also for the production of this 
special gas must be employed, and special apparatus for its com- 
pression and transportation to the buoy must be provided. All 
this renders the use of compressed gas for buoys complicated and 
costly, and there are similar objections to the employment of 
electricity for that purpose. 
In the year 1896' I read before this Society a paper showing 
that I had invented a system of buoy illumination by petroleum, 
much simpler than the employment of either gas or electricity, 
and so economical, that it costs, in one of its forms, only one penny 
for every twenty-four hours, or half-a-crown a month ; and I showed 
the Society how this was done by the use of the ordinary petro- 
leum of commerce burned in special lamps; so that, upon buoys 
or beacons in places difficult of access, the light is continuous, and 
does not require the attendance of any light-keeper for a month, 
two months, or three months, as may be desired. These petro- 
leum buoy-lamps are now used in many of our harbours, and, as 
a distinguishing mark in certain positions, the character of the 
light of some of them has been varied by the interposition of opaque 
or coloured revolving screens. ‘These screens are caused to revolve 
by the upward current of heated air from the lamp acting dn a set 
of mica blades placed vertically over the chimney of the lamp, these 
blades being connected with the screens and attached to a vertical 
steel spindle working in a cup of agate or hard steel. The details 
of this plan I brought before the Society in the year 1897.’ 
But it was found in practice, that while the ight never failed 
even in very stormy weather, yet with respect to the variation by 
occultation or otherwise, to which I have above referred, two 
difficulties were experienced, one with respect to the occultations 
of beacon lights and the other with respect to similar occultations 
of buoy lights. . 
The difficulty as to beacons was this: the hard steel or agate 
cup in which the spindle worked was exposed to the heat of the 
lamp, and it was found, chiefly in warm weather, that a sticky 
deposit from the products of the combustion of the petroleum 
clogged the spindle in its bearing in the cup, and caused the 
Se a Sa TN a ce 
1Proceed. R.D.S., vol. vili., p.377. 2 Proceed. R.D.S., vol. viii., p. 519. 
