NavList:

Hello John

Your assessment that the Wermacht device followed the Soviet device would depend on the order the devices were manufactured in.  I'd like to explore that a bit.

Bill Morris, author of The Sextant Handbook,  obtained that dip meter from Alex Eremenko.  Hopefully, Alex will weigh in on his estimation of the date of manufacture.  Bill Morris also corresponds here, perhaps he will offer a guess at the date of manufacture.

The device you are discussing is Wehrmacht issue.  That makes the device you are discussing of WWII vintage. 

I've handled Alex's dip meter and it did not appear to be as early as WWII.   Our discussions had Alex's dipmeter being used to closely fix the position for launch of missiles at sea.  If so, that would imply the 1960's and therefore, you have the devices out of order.

On the other hand, the concept of the dip of the horizon is well understood historically well before either device.  Scientific American published an article on using a prism to measure the dip of the horizon in 1903.  I am quite confident earlier articles and earlier devices will turn up.  I possess a device which can measure the dip of the horizon which was manufactured in 1905, of a different mechanical arrangement. 

That one device influenced the other, in the order you imply, is probably not the case.  Yet dip meters have existed in various forms well prior to WWII. It is possible that the device you are discussing is a dipmeter, as the parameters offered fit it. 

Some data points I would like to know.  You offered a maximum measurement of 2° around 180°.  What is the resolution of your device?  Does it read to minutes of arc?  Tenths of minutes?   In order to measure the dip, the device must actually measure beyond 180°.  That is you measure down to the horizon.  Therefore, the total angle is 180° + twice the dip.  Does your device in fact measure down to the horizon??

Brad