[GreenKeys] Historical instrument catalogs

[Craig Sawyers]

Hi all

While poking around on the web, I found a superb collection of
manufacturer's catalogs from the late 1800s to the early 1900s.  Included
items in the Cambridge Scientific Instruments catalog of 1908 is a "Hertzian
wave detector" - basically a diode.  But made from a sandwich of lead-lead
peroxide-platinum, it uses a 2V accumulator to bias it.  There are hints
about how to polish the lead and platinum surfaces and how to store the lead
peroxide pellet in a little calcium chloride dessicator when not in use.

And if you want a high sensitivity version, replace the lead with thallium!
And reduce the bias to less than 1.5V.  I don't think that toxicity figured
in the vocabulary way back then.

Price was an astronomical $96 with a further $46 for the indicating galvo.
This is precisely the sort of comms stuff that was on Titanic.

General link is
http://www.sil.si.edu/DigitalCollections/Trade-Literature/Scientific-instrum
ents/explore.htm

Enjoy

Craig