Carbon is a wonderful substance. It is familiar to us in the form of soot, lampblack, charcoal, graphite (the "lead" of lead pencils) and diamond. The puzzle which the electric lamp inventor had to solve was to get this protean substance in the form of a fine tough thread. Edison scoured the world of botany to discover a natural fibre which would serve the purpose; and he at last selected bamboo. Swan took the more scientific line of making a carbon filament from the beginning, as it were. His raw material was nothing more recondite than cotton-wool. "From cotton-wool to candle power" was the phrase which once summed up the making of electric lamps.
The first step was to dissolve the cotton-wool in chloride of zinc, producing after treatment which need not be detailed here, a soft mass, with the consistency of golden syrup. This mass was squirted slowly through a small hole into a jar of alcohol, which converted it into a whitish thread, not unlike fine marcaroni, and after washing and drying, the coils, now fine and tough, were wound on "formers" which gave the filaments the looped curv e familiar in the old carbon lamps. When these formers were placed in a furnace and baked, everything except the carbon was driven off, and the original mass of cottonwool was thus transformed into hard and tough threads of pure carbon.
The rest of the process of lamp-making lay in mounting each thread in a glass bulb from which all the air was extracted. Were any air left in the bulb, the carbon filament, raised to a white heat by the electric current, would burn and disappear. Mou nted in a vacuum it would live for several hundred hours of light-giving.
From The Story of the Lamp, on Kilokat's Antique Light Bulb Site<
Sunday, November 15, 2009
Friday, September 12, 2008
Hobart Snow
http://portal.archives.tas.gov.au/menu.aspx?detail=1&type=id&id=3796
Dated 1950, (1951?)
http://nla.gov.au/nla.pic-an6439325
1882
Dated 1950, (1951?)
http://nla.gov.au/nla.pic-an6439325
1882
Friday, July 18, 2008
Old Hospital
From Zeehan, including interior of dispensary, wards, operating theatre
http://images.statelibrary.tas.gov.au/Detail.asp?ID=au-7-0016-125442038
http://images.statelibrary.tas.gov.au/Detail.asp?ID=au-7-0016-125442038
Thursday, May 1, 2008
Monday, January 14, 2008
Lion Monument
Löwendenkmal -- a memorial to the Swiss Guards who were killed during the French Revolution
I'd forgotten the story that went with the Lion Monument at Lucerne.
One page with photo and short blurb.
Close up photo
Lots of good photos. Not much information. Too many aimed at tourist sites.
From Wikipedia
The most famous episode in the history of the Swiss Guards of the Royal household was their defense of the Tuileries Palace in Paris during the French Revolution. Of the nine hundred "Gardes Suisse" defending the Palace on August 10, 1792 more than six hundred were killed during the fighting or massacred after surrender. An estimated two hundred more died in prison of their wounds or during the September Massacres that followed. Apart from a few Swiss who were helped to escape from the Tuileries by sympathetic Parisians the only survivors were a 300 strong detachment which had been sent to Normandy to escort grain convoys a few days before August 10. The heroic but futile stand of the Swiss is commemorated by Bertel Thorvaldsen's monument in Lucerne dedicated in 1821 and showing a dying lion collapsed across symbols of the French Monarchy.
Link from above article The Attack on the Tuileries
From http://www.everything2.com/index.pl?node
(They) were given no orders as to what they should do when the murderous revolutionary mob approached. They did not know that the King and Queen had escaped the palace, and faced with overwhelming odds, laid down their arms in the face of annihilation by the irate peasants. Having searched the palace and finding the king gone, the crowd sated their blood-lust by turning on the Swiss guards who were overwhelmed by the 30,000 strong mob.
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