The mechanical stroboscope..................

Stroboscopes would at first impression be considered to be operated by a neon or zenon tube and be electrical in nature....but this post is about a mechanical stroboscope I had for years...a Stroborama.....and which finally I found a good home for with an aviation enthusiast  Roy Fox, who has a De Havilland DH89 Dragon Rapide and a Comper Swift aircraft.
Made in France, with a bevelled glass which tends to date it in the mid 1920s I was unsuccessful years back in finding the company that made it...
I had a series of books, printed about 1938 on aeronautical engineering which had an article on the rotoscope and eventually I got around to reading it...there were about 7 volumes in the set... and there was a photo of the rotoscope, another version on the stroborama I had in use....
I sold the books to the owner of the Dragon and Comper along with the stroborama, so they went to a good home and Roy Fox was thrilled to get them.
An interesting aside is I would often have master tachometer testers calibrated to do with my former instrument business and while the firm who did this work for me couldn't cope with a mechanical device such as this, they suggested another laboratory who, on my telephone call declared there was no such thing as a mechanical stroboscope, they were electronic....
A stroboscope, also known as a strobe, is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. 
So lets look at my stroborama stroboscope.....
It uses a slot, the width of which can be adjusted, through which your eye observes the target object and the slot is rotated by hand motion geared and which has a smooth action....
The rotating target object can be slowed down and its motion completely stopped...as there is a calibrated scale, then the rotational speed of the target in rpm can be ascertained.
In the case of the rotoscope in the illustrations, the tachometer in the cabin of the aircraft can be compared to the actual speed of the propellor observed via the rotoscope/stroborama.

The rotoscope, a description and a photo in use....

I mentioned the usual electronic one....
Illustrated below is the zenon tubed version I still have.... the neon tubed version was sold on....

Possibly the last motorcycle race during WW2....

The 1939-1945 world war, WW2, was well underway for Australia when the Blue Mountains TT was held in the small town of Blackheath to the west of Sydney on Anniversary Day 27th January 1941.....
I've no idea why it was run then, guess the population needed entertainment or a diversion from the hard reality of life and world war.....
The circuit was built specially by the Blackheath Municipal council, no doubt at considerable cost to their ratepayers and was only ever used the once...never again after hostilities had ceased....
Jim Scaysbrook in his bi-monthly publication, Old Bike Australasia magazine, will do a more in depth look at the circuit in a forthcoming edition....
But lets have a look at the report in the motorcycle publication of the time, the February 1941 copy of "The Australian Motor Cyclist".....

As well I've some other original photographs taken during the meeting....

Ron Kessing on his 1938 Mk.7 KTT Velocette followed by  Eric McPherson on his 1939 Mk.8 KTT Velocette during the Senior race....

Eric McPherson easily wins the Junior race on his 1939 Mk.8 KTT.
Then last weekend following a Velocette/Vincent rally at a nearby town, we found the circuit and it is intact today with a fair amount still dirt/gravel...
So we duplicated the first corner pictured on the cover of AMC Feb.1941 and I've stitched the two photographs together for comparison.....