New here :-)

On Mar 7, 10:32, Geoff Roberts wrote: Since we're getting all accurate again, .. The kilogram was defined in a way intended to represent the mass of one cubic decimetre of water at its maximum density, and to this end a suitable platinum-iridium cylinder was constructed to be "the standard". But it was later found to be slightly inaccurate, so the definition of the standard was redifined to be the mass of the cylinder. Thus 1 litre doesn't *quite* fit into a cube 10cm a side, being 28 ppm too large :-) In 1964 the litre was redefined for practical purposes to equal a cubic decimetre, but not for work of high precision. An imperial gallon is defined in terms of a mass of water (weighing 10 pounds at a density of 0.988859 grams per cc, ie at 20C, in air at a certain density, against weight of a certain density, all stated in metric units!). 15C. -- Pete Peter Turnbull Network Manager Dept. of Computer Science University of York