XII. 
NOTE ON IMPROVEMENTS IN THE MEANS OF CAUSING 
OCCULTATIONS OR FLASHES IN BUOY LAMPS AND 
BEACONS IN WHICH THE LIGHTS BURN CONTINU- 
OUSLY FOR A MONTH OR A LONGER TIME. By JOHN 
R. WIGHAM, M.R.1.A. 
[Read June 21 ; Received for Publication Juty 3; Published Juty 31, 1899]. 
In a previous paper read before this Society,! I described an 
arrangement of lenticular apparatus, by which the most powerful 
light-house light, of oil, gas, or electricity, could be kept con- 
tinuously in the view of the mariner; thus giving him the advan- 
tage of the most powerful beam which it is possible to throw upon 
him by the most powerful revolving lens, and yet so arranging 
the apparatus that the light never leaves his eye, fulfilling in 
this the great desideratum of the sailor; namely, the strongest 
light-house light which an annular lens can transmit, while at the 
same time, unlike ordinary revolving lights, it is visible con- 
tinuously. ‘That such a light will yet be placed within his reach 
by the light-house authorities I sincerely hope; but, notwithstand- 
ing that its feasibility has been practically demonstrated, no one 
can predict when this great benefit will be conferred upon him. 
Such great light-house lights are of course only placed on 
leading landfalls and prominent positions on the seaboard for the 
distant guidance of the sailor; but it is exceedingly desirable to 
give him also every possible assistance in the closer but often 
more difficult and dangerous navigation of estuaries, rivers, and 
harbours. It is, therefore, satisfactory to know that of late years 
increased attention has been given to making the system of buoy- 
age in such places useful after dark, as well as by day, by placing 
upon buoys and beacons, lights, by which their positions may be 
clearly indicated at night. Both compressed gas and electricity 
have been used as buoy-lights; but both gas and electricity for 
this special purpose are expensive and troublesome to maintain in 
a state of efficiency. For example, if compressed gas be the 
illuminant, oil-gas or rich cannel-gas must be used; because 
1 Proceed. R.D.S8., vol. viii., p. 347. 
