I recently came across this early gun metal cased military style chronograph. Case only has numerical marks, none other. The column wheel movement is not marked, runs strong, and the chrono functions work properly. The dial has a 30 minute register and a 60 seconds register. What I would like to know is what the 25-300 outer chapter on the dial indicates?

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Your Swiss chronograph is similar to watches issued by various military forces in WWI. The difference is that the military issued watches seldom had roman numerals and issued watches had military property markings.

You chrono is a commercial item, it is of the type commonly purchased by military officers, sportsmen, aviators, and others who might find the timer of use in daily activities.

Hi Ernest,
I was just looking through this post and realized I have the little brother to your watch. serial # 5556. If you ever find any maker information please post it here. I would sure be interested in it.
Ray

Hello Ray. If I ever take it down for a service I'll let you know the maker. I still would like to know what the outside chapter numerals 25 to 300 represent? It must have been for a specfic use I assume. It was suggested by another military collector it was for artillary use, but that was speculative.

Hello Ernest,

this special dial kept me thinking and searching for days, as I am also very interested in what this scale ranging from 0 to 300 could be for.
So I had a look at the following site:

info-uhren.de

Unfortunately it's in German language, but scrolling down you will find this picture:

Mikrograph

The first one on the left of the last row is an example of the dial of a stop watch with a scale ranging from 0 to 300, related to it is the term "Mikrograph".

A google-search led me to this site:

hautehorlogerie.org

According to this site, "Mikrograph" is an invention of Mr. Edouard HEUER, it's a stopwatch that enables you to measure time with an accuracy of 1/100th of a second.

If you take a look at this site

chronographen.faszination-uhrwerk.de

you'll see a picture of patents from 1888, where you can see a watch that looks nearly the same as yours.

I don't know how this "Mikrograph"-thing could make any sense to your watch, as it would need a hand that takes three seconds for one rotation, to measure the 1/100th of a second, but maybe the real watch experts (wich I am not) here can take this as one of possible starting points for an explanation.

Best regards
Gerd

I don't know for sure, but my thought is this is not a military watch but rather a watch with a stop watch function. If you think about it, the 1-300 markings turn out to be one-fifth of a second markings which is a fairly standard interval of time for a stop watch of this period.

Hi Jim,

1/5th of a second? Sounds okay to me, but what would be the sense in knowing that 300/5th of a second are 60 seconds? In other words - why aren't there just the indexes, and what is the scale from 1 to 300 for?

Regards
Gerd

Gerd,

I believe the intention is of the scaling is to break a second down further to .2 increments such as 10.2, 10.4, 10.6, 10.8 and if the sweep stops between these small hash marks you coud read it as 10.1, 10.3, 10.5, 10.7. 10.9 seconds for example. To put the increments in spacings of .1 seconds would make it difficult to read. I have an Invicta Chrono which is scaled the same way.

Steve

Hi Steve,

thank you very much indeed for your thoughts. Sounds logical, but it still doesn't really explain the scale 1 - 300! For breaking the seconds into .2 increments we would only need the indexes! Not the digits 25, 50, and so on.

Best regards!
Gerd

Hi,

outer scales usually subtend direct phenomenal readings such velocity, pulsations, speed of sound (distance) etc which is not the case on this dial.

Here dial is simply staggered in 1/5 sec as per the accuracy and quality of the chronograph.

rgds

Enzo

I agree with Enzo. A watch of this type has a movement that is made to the level of accuracy where the smallest unit of time it can measure is 1/5 of a second. The 300 and intermediate numbers are simply the indicators of how many 1/5 seconds there are in a one minute sweep.

There may also be an element of marketing in having such numbers and markings on the dial - it lends a sense that this is a a chronograph/stopwatch/timer rather than just an ordinary pocket watch.

Thanks, Enzo and Jim!

Regards
Gerd