Flagstaff Hill Maritime Museum and Village
Machine - Dioptric Apparatus, mid 19th century
... 1824. The company specialised in making crown window glass, the company ran into difficulty and its survival was guaranteed in 1832 by investment from Chance's brother, William (1788 – 1856). ...1824. The company specialised in making crown window glass, the company ran into difficulty and its survival was guaranteed in 1832 by investment from Chance's brother, William (1788 – 1856). ...
Before the introduction of electricity, lighthouses had a clockwork mechanism that caused the lens to rotate with a light source inside that was either powered by Kerosene or Colza oil. The mechanism consisted of a large weight attached by a cable through the centre of the lighthouse to the top where the cable wrapped around a barrel, drum or wheels that controlled the speed of the lights rotation by a clockwork mechanism. The keeper would crank the clockwork mechanism, which would lift the weight ready for the next cycle similar to an old grandfather clock mechanism.
Once the weight lifted to its apex at the bottom of the first landing, the keeper would let it fall, which would pull on the cable, which would, in turn, operate a series of gears activating the rotation of the Fresnel optical lens, which would then rotate to create the lighthouse’s unique light speed of rotation characteristic. Creating a specific characteristic required a way to regulate the speed of the rotation, and was important as sailors could identify a particular light by its speed and time between flashes. The weight had to fall at a certain rate to create the proper rotation speed of the lens and a regulator within the mechanism accomplished this.
History:
From 1851, Chance Brothers became a major lighthouse engineering company, producing optical components, machinery, and other equipment for lighthouses around the world. James Timmins Chance pioneered placing lighthouse lamps inside a cage surrounded by Fresnel lenses to increase the available light output these cages, are known as optics and they revolutionised lighthouse design. Another important innovation from Chance Brothers was the introduction of rotating optics, allowing adjacent lighthouses to be distinguished from each other by the number of times per revolution the light flashes. The noted English physicist and engineer, John Hopkins invented this system while employed at Chance Brothers.
Chance Brothers and Company was a glass works and originally based in Spon Lane, Smethwick, West Midlands England. The company became a leading glass manufacturer and a pioneer of British glass making technology. The Chance family originated in Bromsgrove as farmers and craftsmen before setting up a business in Smethwick near Birmingham in 1824. They took advantage of the skilled workers, canals and many other industrial advances taking place in the West Midlands at the time.
Robert Lucas Chance (1782–1865), known as 'Lucas', bought the British Crown Glass Company's works in Spon Lane in 1824. The company specialised in making crown window glass, the company ran into difficulty and its survival was guaranteed in 1832 by investment from Chance's brother, William (1788 – 1856). William owned an iron factoring business in Great Charles Street, Birmingham. After a previous partnership that Lucas had dissolved in 1836, Lucas and William Chance became partners in the business which was renamed, Chance Brothers and Company.
Chance Brothers invented many innovative processes and became known as the greatest glass manufacturer in Britain. In 1848 under the supervision of Georges Bontemps, a French glass maker from Choosy-le-Roi, a new plant was set up to manufacture crown and flint glass for lighthouse optics, telescopes and cameras. Bontemps agreed to share his processes that up to then had been secret with the Chance Brothers and stayed in England to collaborate with them for six years.
In 1900 a baronetcy was created for James Timmins Chance (1814–1902), a grandson of William Chance, who had started the family business in 1771 with his brother Robert. Roberts grandson, James became head of Chance Brothers until his retirement in 1889 when the company became a public company and its name changed to Chance Brothers & Co. Ltd.
Additional information:
Lighthouses are equipped with unique light characteristic or flashing pattern that sailors can use to identify specific lighthouses during the night. Lighthouses can achieve distinctive light characteristics in a few different ways. A lighthouse can flash, which is when brief periods of light interrupt longer moments of darkness. The light can occult, which is when brief periods of darkness interrupt longer moments of light. The light can be fixed, which is when the light never goes dark. A lighthouse can use a combination of flashing, oscillating, or being fixed in a variety of combinations and intervals to create individual light characteristics.
It is a common misconception that a lighthouse's light source changes the intensity to create a light characteristic. The light source remains constant and the rotating Fresnel lens creates the various changes in appearance. Some Fresnel lenses have "bulls-eye" panels create beams of light that, when rotated between the light and the observer, make the light appear to flash. Conversely, some lenses have metal panels that, when rotated between the light and the observer, make the light appear to go dark.
This Dioptric clockwork apparatus used to turn a lighthouse optical lens is very significant as it is integral to a lighthouses operation, we can also look at the social aspect of lighthouses as being traditionally rich with symbolism and conceptual meanings. Lighthouses illustrate social concepts such as danger, risk, adversity, challenge and vigilance but they also offers guidance, salvation and safety. The glowing lamp reminds sailors that security and home are well within reach, they also symbolize the way forward and help in navigating our way through rough waters not just on the oceans of the world but in our personal lives be it financial, personal, business or spiritual in nature. Nothing else speaks of safety and security in the face of adversity and challenge quite the way a lighthouse does. Revolving dioptric clockwork apparatus used to turn a Fresnel optical lighthouse lens. A cylindrical cast metal pillar and cabinet painted green with 3 glass doors enclosing the top section. Inside the pillar/cabinet is a large clockwork mechanism used to turn and regulate a lighthouse light by means of weights and a chain attached to same.
One door has the name "Adams Mare" in metallic dots similar to "Braille" to the inside edge of door frame.shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, flagstaff hill, maritime-museum, shipwreck-coast, warrnambool, flagstaff-hill-maritime-village, revolving dioptric mechanism, dioptric mechanism for lighthouse, lighthouse clockwork timing mechanism, acetylene lighthouse light mechanism, 19th century lighthouse mechanism, kerosene light, fresnel lenses, colza oil, chance brothers
Narre Warren and District Family History Group
Bendigo Historical Society Inc.
Flagstaff Hill Maritime Museum and Village