Potassium Dichromate and the Campaign of 1870

In a message dated 28/04/05 18:50:41 GMT Daylight Time,
schuyler@bellsouth.net writes:

> Oh, and I wouldn't recommend feeding small children alt process prints,
> either.
..............................
Following is from, ''The Chemistry of Light and Photography,'' by Dr. Hermann
Vogel, Professor in the Royal Industrial Academy of Berlin. Published by
Henry S. King & Co., London 1876
.........................................
''In the campaign of 1870, the well-known pea-sausage (erbswurst) was one of
the most important articles of food for the army, and was pepared daily by
thousands. The fabrication of the interior portion caused little difficulty, but
the obtaining of many skins created much difficulty. As the supply fell
short, a substitute was saught in vegetable parchment. This paper, which is
produced by dipping blotting paper in sulphuric acid for about a second, then
washing and drying, is distinguished by its skin like properties of resistance. It
is impenetrable to water, and difficult to tear. It is therefore used for
the production of bank-notes. It was attempted to make sausage skins of this
paper, by doubling a sheet cylindrically and pasting it together. No glue or gum
can however resist the effect of the boiling water in which the sausage has
to be cooked, and so the artificial sausage skin fell asunder. Dr. Jacobson
solved the problem by producing an adhesive substance, with the help of the
chemical action of light, which could resist boiling water. He mixed the glue
intended for the sausage skin with bichromate of potash, and exposed the glued
parts to the light. This made the glue insoluble, and now the artificial skin
endured boiling water thoroughly well. The number of sausage skins prepared in
this way, by the chemical action of light, amounted to many hundred
thousands.''

                 Hot- dog ! ! ! Stay cool. John Grocott - Photographist.
   
Received on Thu Apr 28 13:34:30 2005