Hi!
This outer case belongs to a freind and I think it´s quite strange looking. Now I wonder were it was used and if there is any more interesting information about it.
The case house a Hamilton Chronometer no 50, mod 21. It is very heavy in metal.
Thanks in advance.
Regards!
Bernhard

Hi Bernhard,

That is one interesting case. In some ways it reminds me of the outer cases used with the Hamilton 4992B of WW2.

It looks like something made for extreme conditions, such as arctic navigation or high altitude flight. The two posts on the side, may be for electrical leads, if so, I wonder if there is a small heating element inside ? If my hunch is correct, a small heating element may have been necessary to keep a chronometer functioning properly in sub-zero weather.

Are there any markings on it?

Best regards,
Greg

Hi!
I know what you mean by the outer case for 4992B, just bought one. There are no markings on this case.
I think your hunch sounds good. I think maybe, because the mvt is a Naval observatory one, that it maybe have been in use in colder climate, maybe by marine ground forse (it´s not gimbaled).
Thanks Greg for your answer. If you get any more info, I would be happy if you would let me know.
Best regards!
/Bernhard

Here is some more pictures, maybe you can give some more infromation about it, when it was made, to whom, what´s it pupose. it seems to protected from magnetism and moisture.
/Bernhard

fig 2

fig 3

fig 4

fig 5

fig 6

Interesting! I see it was made by Adamson of Tecumseh, Michigan. About a one hour drive from here. Adamson also made outer cases for the 4992B Navigation pocket watches. Thus, I think it clear that the case is of WWII vintage.

The case is also quite portable, which would not be necessity if it was on a Navy ship. I tend to think it was used in aircraft.

Of course, my curriosity questions what the electrical leads do? Are they hooked up to send a periodic time signal controled by the chronomiter or are they hooked up to a heater?

Great item, I have never seen one like it.

Best regards,
Greg

Perhaps for a tank as evidenced by the shielding and padding for rough riding and cannon vibration. The electric wire would be for a light. Anyway, it LOOKS as tough as a tank!

Actually I bought one outer case for 4992b, you talkin about Greg, the other day on ebay.

If the chronometer that we are talking about was belonging to the aifrforce or army that would not have been a Naval observatory movement and dial. Of couse, the mvt and or dial cold have been change but is that really what you think?
/Bernhard

fig 2

Borrowd this from another freind, it´s from an old manual for somehing that looks like the outer case above.
/Bernarhd

Hi, Bernhard. I was looking for something entirely different in Whitney, and what do you suppose I found on page 487?

It would appear you have a special break circuit chronomiter. The one pictured in MILITARY TIMEPIECES is alot like your friends. The one in the book was "pretested by Hamilton" in 1957 "for the U.S. Army Engineers for a mapping project." The caption does not say the chronomiter was made in 1957, only tested in that year. Whitney states that Hamilton started making these in 1945. I would suppose that any need for break circuit chronomiters prior to regular production would have been filled by modification of existing stock.

Break circuit chronomiters were used for various scientific projects which would have been of interest to the Army and Navy.

As per the 1950 manuel, revised in 1970, the official intended uses of the CHRONOMETER, BREAK-CIRCUIT, M-1 WITH MOISTUREPROOF CARRYING CASE are as follows:

"...to supply a source of accurate time measurements between radio time-signal reception, under the various extremes of climate and temperature encountered in military usage, for accurately timing astronomical observations in the determination of latitude and longitude for topographic survays."

Best regards,
Greg

Thanks a lot Greg, very helpful. Great information.
Regards!
/Bernhard

Hi all,
This is a test because i've never tried to post a scanned page before. This is page one about Bernhard's Chronometer. This is from the book Military Chronometers by Marvin Whitney.
Fred

well that went well.
I'll try and post the rest of the article ( about 6 pages )sometime this weekend.
Happy
Easter
Fred

OK here's the rest of the article. These units were sometimes referred to as " bean pots ".

181

182

183