David Beierl

If I have an email correspondent in Vietnam, can he get in trouble if I say the wrong thing to him, and if so what are the constraints?

Many years ago I lived in Passadumkeag Maine, served by Bangor Hydro power company. I was roughly midway (15-20 miles each way) between two generating plants. One day for a period of half an hour or so my line voltage started cycling between about 85 and 140 volts (measured with an analog meter) with a period of maybe ten seconds. Does anyone have a clue what was happening? This was in '75 or '76 if it helps.

Most of the marine electronics I've dealt with seems to be well lit for twilight, but *way* too bright for night use. My friend and I used to carry sheets of colored film with us when we went on board a boat so we could dim down the displays. On my own boat not only did I have screen overlays but on an Apelco Loran C and a JRC radar I went inside the case and dimmed the lights illuminating the operating buttons. What's your experience?

A) Given present-day materials engineering, how much power could be drawn from a pair of six-inch cubes rotating against each other with a period of 6.9 seconds and infinite torque Assume that failure of the cubes is not an issue. Since in principle power could be drawn in balance from both sides of the Device, it would be legitimate to assume that anchoring one end to the earth is also not a requirement. However if you do choose to anchor one end (preferred), assume granite.

B) Same question, but using say late eighteenth/early nineteenth-century British metallurgy.

C/D) Is this enough information to determine a rough minimum size for the first stage of such a coupling device? If so what would it be? Is anchorage to the earth a first-order problem or does the strength of the six-inch square holes swamp other considerations?

Notes:

a) I'm hoping for answers within a factor of two or so, preferably in horsepower or watts..

b) I don't know the answer myself.

c) The power source in question resides in Terry Pratchett's book _Thud_

I have a copying stand (round pole on a flat base, pantograph arrangement that slides up and down the pole for coarse adjustments. It's well made and in excellent shape, but the rod that holds the camera is inclined eleven degrees up from horizontal, which will cause slight keyholing in anything that's copied. This was obviously intentional, so why?