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Posted By: Walt Mathers on: 06/20/2002 16:18:57 CDT|
Subject: Lanterns, Are Your Sure You Really Wanna Know?
Chuck,(and anyone else fool enough to read this post) ;)|
In your last post you ask'd:
"What kind of lens will I need for the [signal] Lantern? Is it a simple convex lens?"
Answer: The closest way of describing the lens is to say that the ones I've been accustomed with look like the old glass-dome'd library paper weights. Out of its casing it would resemble a rounded blob of solid glass with a flat base. Many were frosted because it was cheaper than working out all of the bubbles, flaws and other such imperfections.
Hold off on bead-pelting the lens in order to obtain the opaque effect. If we can track down the source for your Confederate brass lamp we might find that it could have a clear lens. Don't change anything if not required. Its just that the few documented examples I've been made privvy to had hazzies and not clears.
While on the subject of brass, just remember that tin is lighter than brass when hanging (as a reference light) from a man's belt or being continuously swung over a man's head and we don't know of what material the lantern's were made.
If you must frost the lens, the one at the rear should be done not the front. In addition, however, you'd want to place a piece of clear glass between it and the flame so as not to ruin your lens with prolong'd sootting.
It has always been my belief that achromatic lenses were made by hot gluing two different lenses together over an open flame until the two had become bonded and the glue spread out between and across the two lenses leaving an almost invisible film. The green crackled view you get when looking through certain older optics is a molecular breakdown of the old glue's compounds.
Back to tin/copper lantern design..... I wonder if the Pakistan model wasn't professionally made with the necessary cold roll'd seams. Doing it this way is REALLY important you see. I know of some torches made with soldered side seams that began leaking at first use on account of the heat. The same would occur if prolonged heat were allowed to accumilate in the cylinder of a lantern.
Let me say that besides a nice little machine shop I would STRONGLY recommend you contacting a reliable tin or coppersmith for insight as to how one would go about constructing durable seams.
As to the new Dietz lantern that's hail'd up on the web as being accurate for the early 1850s, don't waste your money, 'cause it ain't even a 19th. century design. Its about 1910 vintage and is called a barn lantern. This very lamp with the side braces was spotted by one of our associates (on the now very old SCARD forum site past ~ sounds Charles Dickenish doesn't it?). I visited the Lamp Society's website and got the skinny. Ths is a very good sister site and like our SCA/SCARD site, has an excellent forum for asking such questions. Along with numerous excellent offerings, the Lantern Society is included amongst the links at SCARD's home page.
I bet this sort of technical stuff bores some of our readers to death. Sorry about that folks. I was just attempting to shed a bit of light on an otherwise obscure area of Civil War signal history. Better step down before someone shooots my punny armour full of holes.
Heres looking at you (I'll leave of the schweethaut part),
Signal Corps Association Re-enactors' Division (SCARD)