Document ID: chunk:federal_register_of_legislation:F2021L01587:reg:2021:p9
Version: federal_register_of_legislation:F2021L01587
Segment Type: reg
Provision Reference: reg 2021 (pt 9/14)
Character Range: 26787–29644

with fuel through multiple wicks[10].
Parabolic reflectors were first used in the lighthouses in Liverpool, United Kingdom, probably around 1763 when they were described in detail by William Hutchinson, the dock master. These were formed from wood and lined with pieces of looking glass or plates of tin.
When light hits a shiny surface, it is reflected at an angle equal to that at which it hit. With a light source placed in the focal point of a parabolic reflector, the light rays are reflected parallel to one another, producing a concentrated beam[11].
The catoptric system was largely obsolete from 1822 when Augustin Fresnel invented the dioptric glass lens. Dioptric systems were refined by Fresnel who took a convex lens and broke it down into a number of concentric annular rings. This design reduced the amount of light absorbed by the lens itself and reduced its overall weight.
The first dioptric lens was installed in the French lighthouse, Cordouan, in 1823. Fresnel's dioptric system dominated lighthouse lens technology for over 150 years. The majority of heritage listed lighthouses in Australia still have dioptric lenses invented by Fresnel but made by others such as Chance Brothers (United Kingdom), Henry-LePaute (France), Barbier, Bernard & Turenne (France) and Svenska Aktiebolaget Gasaccumulator (Sweden).
Around 1900 incandescent burners came into use; in these, the fuel was supplied under pressure and burned inside an incandescent mantle, producing a brighter light within a smaller volume and with less fuel[12].
Throughout the hours of darkness the lightkeeper was required to keep pressure to the burner by manually pumping a handle as can be seen in Figure 7.
Figure 7. Incandescent oil vapour lamp by Chance Brothers (Source: AMSA)
Figure 8. Dioptric lens on display at Narooma (Source: AMSA)
Large dioptric lenses such as shown in Figure 8 gradually decreased in popularity due to  cost and the move towards unmanned automatic lighthouses. By the early 1900s, Australia had stopped ordering such lenses with the last installed at Eclipse Island in Western Australia in 1927. It is interesting to note that prior to that the last was ordered in 1909 for Cape du Couedic in South Australia.
These optical systems were made in a range of standard sizes, called orders—see the Glossary of lighthouse terms in Appendix 2.
Smaller Fresnel lens assemblies continued to be made until the 1970s but eventually lost favour to cheaper plastic lanterns, which still used Fresnel's technology.
In 1912, the Swedish engineer Gustaf Dalén was awarded the Nobel Prize in physics for a series of inventions for acetylene-powered navigation lights. Dalén's system—including the sun valve, the mixer, the flasher, and the cylinder containing compressed acetylene—proved efficient and reliable.
Acetylene was quickly adopted by the fledgling