[GreenKeys] Historical instrument catalogs

[Bob Camp]

Hi

That's a very interesting site.

The only catalog I could find that seemed to be selling US made  
electronic stuff was the CENCO catalog on Wireless Telegraphy. It's  
amazing to see how dependent we were on European sources for this stuff  
prior to World War I.

That makes things like the world standard Teletype all the more amazing  
in the 1920's.

	Take Care!

		Bob Camp
		KB8TQ



On Aug 22, 2004, at 9:56 AM, Craig Sawyers wrote:

> 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
>
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