Ah-ha! I can hear you all say. What do we have here?
Well, I have to admit I paid 150 smackeroos for it some twenty or more years ago, off an antique dealer’s odds-and-ends table during a sidewalk sale in Carlingwood shopping centre, in Ottawa.
And what it is, is a miniature little gem of a pocket current meter, deigned to measure the speed of the flow of rivers or streams. Being so compact it is well-suited for use by an intrepid wilderness explorer-surveyor. It is obviously, a home-or-handmade current meter. Who made it is a mystery. I’m hoping that by showing its photograph here I may gain a serendipitous insight into its origins.
I have assembled it and it works ok. It is very compact. The box, covered in very thin leather, measures only 9.5” x 4.25” x 1.5”.
The only written legend is the formula, dedicated to this particular instrument, and carefully hand-written in small letters in India ink on a paper glued into the lid of the wooden box which says:
n< v="0.213n"> 0.0689
n >4.3 v=0.548n
When n = number of revolutions of the propeller per sec.
“ v = water velocity in ft per second.
Nº 1520 (stamped/engraved on frame and rotor)
Yep! She’s a beautiful little gem. In excellent condition. Should be in a museum.