Brass artillery computer or predictor, Swiss

About 6 x 12 inches, about two lbs, I'm sure it came in some wonderful case but I didn't get that. Got it from a PA militaria dealer at a show about 20 years ago and never investigated it till now. Has many moving parts, it moves in every way you can imagine. Made by Buchi in Bern (yes U should have umlaut, too lazy to look up that code today.) Should be ca. 1930 by way mfg stamped company name, they were around from 1871 till recently, a family company which made a lot of items for Swiss military. I already posted on a specialist forum, British Ordnance Collector's Network, asking ID. Since the important "operator" marks are in English, perhaps made for UK or US military? I know this is a computer for indirect artillery firing, but don't know the exact purpose. The circly thing probably held a magnifying lens at one time, that must be where you read the result of the equation this device solves. ???





Less important photos:

https://springfieldarsenal.files.wordpress.com/2016/01/img_1612.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1611.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1615.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1616.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1617.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1618.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1619.jpg
https://springfieldarsenal.files.wordpress.com/2016/01/img_1627.jpg

 

VERY cool!

 

On 2nd thought it was almost certainly not used by UK or it would have WD marks on it. The Brits marked everything, probably including shoelaces. So the remaining military services using English ca. 1930 would be US Army and who else?

 

Oops, in searching the web I found some of my own posts from 2008, showing this device and some others. I must have been very busy because I'd totally forgotten, but sho 'nuff some of the posts are by "cannonmn" who is me. I'd better download that stuff and file it this time!

http://forum.axishistory.com/viewtopic.php?f=70&t=29159&start=15

 

Very interesting.

 

A moments thought leads me to the conclusion that you use it for rangfinding where the target and gun are at different heights above sea level..

If the target is on the same plane, the same ammunition will land in the same place relative to the gun every time at the same elevation of the barrel. (give or take a bit)

However, if you are firing at a hilltop, or into a valley, the trajectory is not so simple, as it is either curtailed or extended a bit by the lie of the land.

Is it possible that some adjustment of the gadget will show how much extra or less elevation willl give the geographical distance required by the tactical situation?

 

A poster at link in my previous post explains this general type of device. I don't fully understand it yet but I know it only works on the parts of the problem that are in the horizontal plane. Vertical differences are handled separately.

 

The best thing I found since I began this Snow Day project this AM was a detailed description, in English, of the operation of the WWII German "Artillery Computer 34." I have two earlier variants of this and never knew what all the settings were, and now I do because the devices are all very similar. So I'll run one copy to put in each computer's case.

Descriptions and photos of these start on pp. 104.

https://archive.org/details/TME9-325A