Watkins Standard - Rare Actinometer (exposure meter) - by R. Field & Co. 1890-1895, Light meter

This is a nice and rare meter made in England by R. Field & Co. (Birningham) between approximately 1890 and 1895.
It's the Watkins Standard Exposure Meter, a very well made brass cylinder (approximately 63mm long and a weight of approximately 115 grams).
Unlike traditional light meters, which measure light directly, actinometers (such as this one) use light-sensitive paper to measure light.
The cylinder has five graduated scales and one blank section. Four of the scales rotate, and the five scales are labelled A, P, S, D, and E. These scales determine the exposure by allowing various parameters to be adjusted. At one end of the cylinder is a cap attached to a chain; at the other is a “window” used to expose the light-sensitive paper.
This should be one of the first models of Watkins Actinometers.
It isn't the first light meter in history, but from here, in particular Watkins (and shortly after Wynne's), gave impetus to the market of light measuring instruments with several models.
The condition of this meter are very very good (please remember its age…), few light signs of use and of the age, the largest, a small dent near the word Meter on the side of the "window".
The rings rotate well, the glass is intact and, incredibly, a part of the sensitive paper roll is still present.
There is the rarest instruction boocklet (English text, 12 pages) in very good condition, a repaired cardboard box and a copy of "the Watkins Manual" (third edition 1906, more recent than the meter). 150 pages, English text some pictures, a beautiful manual that explains how to photograph, develop and print.

For anyone interested in learning more about these instruments, I recommend visiting this website:

earlyphotography.co.uk/site/entry_E30.html

It explains the instruments and their history much better than I ever could…

A very nice and rare item, refined, fascinating, very well made, and expensive at the time.
An item suitable for collectors of exposure meters or cameras, but also for those who collect scientific instruments.
Hard to find, especially, in these condition and also the instruction booklet is almost impossible to find.
Although it appears to be in working order, it's sold as a collector's item, not for use, I'm sorry but no warranty on it.

The pictures are part of the description and complete it, so, please, look at them carefully.

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Shipping cost, import duties, taxes and charges aren't included in the item price or in the shipping cost.
These charges, if they are due, are the buyer's responsibility.