The Galilean type have just two lenses, an eyepiece and objective They are unsigned. continue printing the same number each time the machine is operated by pushing down the black handle.a corresponding number is llluminated by the reflected light from the subject. The second mode is “consecutive” when it will add one to the number each time it is operated. When at infinity the slanted side of the prism is parallel to the corresponding part of the concave lens and cancels out any light breaking.
They have central screw focusing and extending ray shades.
They are black japanned brass with a thin tooled leather covering.
The test piece is then removed for the test after which it is returned to the space between the jaws that are opened to receive it by moving the pointer arm.
If that is now brought hard up to the test piece the extension can be read off the arc scale..
Unlike the instrument above, which has a built in stop watch, this had to be used in conjunction with a separate stop watch. The range (from 1½ ft to infinity) can then be read from the dial. Originally the property of a civil engineer, it is not clear whether he used this for his work or as a photographic rangefinder. A ‘Tabor’ steam engine indicator made by The Ashcroft Manufacturing Co., Bridgeport, Ct, USA serial no. There would also have been a pack of 100 cards to go on the drum but these would have been used, and a screwdriver which is missing.
It is also missing the 300 page book that would have been supplied with it. N/33000 where Pm = mean effective pressure, L= piston stroke, A=piston area, N=engine rpm.
As above the instruction book and charts are missing. A 4" long linear concave lens (in cross section front and rear of the glass are parallel) is fixed to the base.
A prism is mounted on a carriage with an index mark that slides back and forth along the axis of the instrument.
After that I just found other interesting things to collect. Sold by “SIC” (Swiss Instruments & Components Ltd., 54 Cheam Common Road, Worcester Park, Surrey). A direct reading instrument with three settings, for 500, 5000, and 50,000 rpm.
Hasler SA, Berne, Switzerland workshop tachometer for measuring the speed of rotation of lathe shafts, etc. It has two cone adapters, inside and outside for shaft ends and a wheel for surface speed reading. It has a Blue velvet lined Morocco case with instructions in the lid.“Probator”, made in Germany, revolution counter used in conjunction with a stop watch to measure rotational speed of machinery. The dial is zeroed by the pushing the button at the top and the digital counter is zeroed by turning the knob at the left hand end. Tensometer Ltd, Southampton Row, London Extension and Reduction of Area Gauges.
“Quick Focus Rifleman” telescope by J H Steward Ltd of London. Leather missing from outer tube which is quite battered. Mostly professionally prepared Histology slides (of plant sections).