I acquired this antique instrument some time ago but efforts to identify it to my satisfaction have proven unsuccessful.
Perhaps someone here can assist – it measures 12cm across, about 5cm deep and has a hand adjustable outer ring with only a short 0 to 10 ascent / descent scale on it (currently located where the needle’s point is situated). A fixed scale measures from 0 at the bottom to 4000 at the top with another fixed scale on the inner face reading from 27 to 33 (also with an ascent / descent direction – both fixed scales have gradients in parts of 10 so do I assume it measures meters?
It has “Davis & Son London & Derby” with the word “Compensated” inscribed on the face and a movable eyepiece on the outer casing.
There are no serial numbers, part / model numbers or other markings on the casing. Nevertheless a very attractive item.
I was led to believe that this instrument could have come from an airship – could this be the case?
By: antiqueaviation - 28th December 2012 at 17:38
Thank you all very much for your input. While I am a bit disappointed that it is not, as I had hoped, aviation related it is, as you all seem to think, a very nice item nonetheless.
I may very well decide to keep it as a curiosity, rather than let it end up on ebay!
By: bazv - 28th December 2012 at 07:31
As Versuch said – a lovely instrument,here is a link with a pic of maybe a slightly later instrument c/w carry case…
By: bazv - 28th December 2012 at 07:13
Yes looks like it is a Mining/surveying Aneroid,if you go to page 9 of this 1877 Davis catalogue you can see what looks like maybe a slightly older version of it but still with the eyepiece for reading the fine vernier scale…
rgds baz
By: Portagee - 28th December 2012 at 00:05
Davis & Son is now Davisderby Ltd.
Might be worth asking them directly for any info, their website does have a brief history section covering surveying instruments.
By: antiqueaviation - 27th December 2012 at 18:38
If it will help I attach a picture of the back – there are no lugs but an unusual sliding tab on the bottom. I have no idea as to the purpose of this part. All else there is on the back is a recessed adjusting screw. I have it alongside an old matchbox to give an idea of size.
A pity if it is not airship or hot air balloon related – I guess the ascent / descent inscription led me to accept that theory. Will still like to know its function though.
By: Versuch - 27th December 2012 at 00:19
I cannot confirm if its Airship or not,but these instruments where used by early
Surveyors 1800s/1900s to assist calculating height etc.
Never seen one with the eye piece, and its double the usual size,it maybe is
a master,by which others are set.
Airship items normally have 3-4 lugs or pins to hold it in place.
A very nice item .
Cheers Mike
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December 26, 2012 at 8:01 pm