The Photometer

The outside of the photometer

The outside of the photometer

As I’ve stated over (and probably over again) in past posts, we at the Beaumier Heritage Center have a plethora of items. One of our larger collections is of old scientific equipment, much of which came from NMU’s physics department. Many of the items were identified by professors of the department around 1999. Luckily, this item was one of them. If we hadn’t been told what it was, we may never have been able to guess exactly what it was.

This artifact is called a Bunsen Photometer and its use was described to us by Dr. Mark Jacobs, Associate Professor in the NMU Physics department.

“The eyeshade/mirror arrangement lets the user look at both light sources (at either end) simultaneously. The images are diffused and combined. The position of the slider is adjusted until the (combined) image has uniform brightness. Then the relative brightness of the two sources can be computed from:

(L1 / L2)= (d1 / d2)2

Where d1 and d2 are distances read on a scale.” -05/07/1999

Where the candle would go

Where the candle would go

This once again illustrates the importance of having a clear understating of the items that are coming into a collection and getting as much information as possible from the people that are gifting these items. And so the mystery of this strange device was never a burden to any poor undergraduate to find out, which I, for one, am very glad.

Written by Stephen Glover of the BHC


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