On Mon, 4 Apr 2016 20:37:27 +0100, "NY" wrote:

"Ken Blake" wrote in message
.. .
On Mon, 4 Apr 2016 10:45:33 +0100, "NY" wrote:


(*) I needed to work out roughly how heavy a copper water cylinder would
be
when full of water. I only had an imperial tape measure. Measure diameter
and length, and volume is pi r-squared l - but this gives volume in cubic
inches and I only know that "a pint of pure water weighs a pound and a
quarter" ie that a gallon weighs 10 lb. How many cubic inches ina gallon -
buggered if I know, even to an order of magnitude. I ended up converting
lengths to centimetres (using 2.5 cm = 1 in approximation) and working out
the volume in cc, and then the mass follows from knowing that 1000 cc
weighs
1 kg.



I just used convert.exe. It tool a fraction of a second to find out
that there are 231 cubic inches in a gallon.

This was in the days before people had computers, the internet etc, and even
calculators were just basic four-function ones, with no built-in conversion
factors.


Ah, OK. Understood.