Does anybody have an idea what this is?
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Here's more information, although it doesn't qualify as a hint: It was made in the USSR in the 1960's.
It looks like some sort of general purpose slide rule, but with circular scales. I guess the knobs move the pointer and one scale relative to another. It is hard to tell the size, but looking at the scale divisions my guess is that it is a pocket instrument that an engineer might carry for quick rough calculations.
On the left pic we have an inner logarithmic scale, and an outer scale logarithmic scale with squares. On right pic the outer scale seems to be an inverse of the scales on the first side. Then you can see a degrees scale for sines and the inner scale, which is actually a spiral I think (the end seems to disappear under the flash flare), is a degrees scale for tan.
I suspect it is a general purpose calculator rather than for a specific problem because it has pi marked. Also there is a value C marked at 1.125 -- I cant actually work out now what it is for, but I seem to remember from 1950s linear slide rules there was a small offset on the cursor which one used for some simple calculations the nature of which elude me at present. I have never seen a slide rule like this, and by the 1960s although we still used 12 inch linear slide rules a lot, calculators were beginning to take over for a lot of work.
As a note relevant to this course measuring forum this device would not have been sufficiently accurate for John Jewell in 1961 to do his historic calculations in proving the calibrated bicycle method of course measuring. He must have done all the multiplications and divisions by long hand arithmetic or log tables. You guys have it easy today. Think of it -- no calculator or spread sheets available then. I take my hat off to the pioneers of course measurement
On the left pic we have an inner logarithmic scale, and an outer scale logarithmic scale with squares. On right pic the outer scale seems to be an inverse of the scales on the first side. Then you can see a degrees scale for sines and the inner scale, which is actually a spiral I think (the end seems to disappear under the flash flare), is a degrees scale for tan.
I suspect it is a general purpose calculator rather than for a specific problem because it has pi marked. Also there is a value C marked at 1.125 -- I cant actually work out now what it is for, but I seem to remember from 1950s linear slide rules there was a small offset on the cursor which one used for some simple calculations the nature of which elude me at present. I have never seen a slide rule like this, and by the 1960s although we still used 12 inch linear slide rules a lot, calculators were beginning to take over for a lot of work.
As a note relevant to this course measuring forum this device would not have been sufficiently accurate for John Jewell in 1961 to do his historic calculations in proving the calibrated bicycle method of course measuring. He must have done all the multiplications and divisions by long hand arithmetic or log tables. You guys have it easy today. Think of it -- no calculator or spread sheets available then. I take my hat off to the pioneers of course measurement
Difficult calculation without electronic calculators may be the reason that early US calibration courses were usually 1 km, 1 mile or 1/2 mile. Makes the math easier, if not the cal course layout.