Light types

There are various types of light houses using various light sources listed in 1892.

Lights

Dioptric (refractive)

The light source is surrounded by a set of complex glass lenses that either are fixed or which revolve around the light. fixed lenses focus their light equally around their circumference. Revolving lights are also seen at all times but attain a period of greatest brilliancy when the viewer is in line with the focused beam from the lens.

Catoptric (reflective)

The light source is surrounded by a series of lenses but , when fixed, backed by a concave mirror which concentrates the light against the lens in particular directions. The area behind the mirror is "dark". In revolving catoptric systems the mirror and lenses rotate so the beam apparently sweeps across the sky; these lights have distinctive light and dark phases.

Cato-Dioptric

A combined system which uses a revolving mirror to concentrate the light causing it to appear to flash while allowing it to be seen constantly as in fixed dioptric systems. Brunette Island had the only such system listed.

Each type of light system was rated according to its luminosity. The most common were 4th, 5th, and 6th order lights corresponding to the various diameters of the lenses; eg. 4th order lenses have a diameter of about 3 feet; 8th order lenses about 10 inches. The largest lens in use in Newfoundland is at Cape Race, at about 8.5 feet (hyper-radial), it exceed the 1st order size of about 8 feet.

Sources

All the lights listed (but one) used kerosene wick systems as light sources. The various types are self descriptive.

2 wick concentric
Mammoth flat wick
No. 1 circular
Silber patent circular burner
Argand (No. 8; 1; No. 6, Gas; 12 , No. 9)
Duplex
1 Argand
1 1/4 Argand