Strange device - can you help ?

[NewDazzler]

Something has recently come into my possesion and I have no real idea what it is.
It consists of three aluminium tubes about 1inch diameter each, two of which are about 8 inches long the third about four inches long, all have caps with clear glass tops on both ends. Also in the box are several optical filters which will fit the tubes these appear to have different levels of density/clarity of their translucent glass. Also there is a measuring tape graduated with markings consisting of numbers but no units. The scale of the measuring tape is not constsnt, appearing to be a kind of logarhitmic scale. A plate in the box suggests that the manufacturer "Paterson Engineering" was involved in water filters and oil filters, so I'm guessing that it's some kind of water or oil meter for measuring the clarity or number of particles of obscuring matter in a sample of either water or oil. Anyone who knows what it is or better may have used one please let me know. Thanks in advance.

[RATTER15]

This site may be of interest to you, I think you are on the right lines. http://www.google.co.uk/products?q=%22Paterson %20Engineering%22&svnum=10&um=1&hl=en&safe=off &filter=0&ndsp=20&ie=UTF-8&oe=UTF-8&sa=N&tab=i f

[NewDazzler]

Thanks, I had googled most combinations, but not thought to look for books. Now all I need is to find one of those books in the local library, cheers

[BBWCHATT]

Paterson Engineering
Rear of 2 High Street Cowley , Uxbridge, UB8 2EN
Tel: [phone]