Measuring microfortnights and megafurlongs

All pharmacists are familiar with the International System of Units (SI), based on the metre, the kilogram and the second —and also, if you wish to be pedantic, the ampère, the kelvin, the candela and the mole.

But if you find SI dull and boring, why not try the FFF system, based on the furlong, firkin and fortnight? FFF was devised as a joke by computer scientists and has now acquired a following among sad dorks like me.

The FFF base unit of time, the fortnight, is equivalent to 1,209,600 seconds in the SI system. The base unit of length, the furlong, is 220 yards (one-eighth of an imperial mile) and equivalent to 201.168m in the SI system.

And the base unit of mass is the mass of an imperial firkin of water, which is nine gallons or 40.823kg. (Lovers of real ale will know that firkin is also the name of a cask of this size, equivalent to a quarter of a barrel.)

These units, and others derived from them, have no practical value, which is part of the fun. For example, the basic unit of velocity, one furlong per fortnight, equates to 1.663x10^-4 m/s, a rate of progress that is barely noticeable to the naked eye, being roughly 1cm per minute.

A garden snail on amphetamines would have trouble reaching a speed of 100 furlongs/fortnight; a plane cruising at 420 knots (216.2 m/s) is travelling at 1.3 megafurlongs/fortnight.

One of the more easily understood units in the FFF system is the microfortnight, because it is equivalent to 1.2096 seconds. Indeed, so useful is it that one computer operating system employs it for a variable that fixes the period the system will wait for an operator to set the correct date and time if it detects that the current value is bogus.

So that I can include an allusion to health care in this piece, I have calculated how to express body mass index in the FFF system. In doing so, I have made the serendipitous discovery (if my computations are correct) that the BMI unit of kg/m² is as near as dammit 1,000 firkins/furlong².

So, if you know that your BMI is, say, a comfortingly normal 25 kg/m², you can announce that you have a BMI of 25 kilofirkins per square furlong. And welcome to the FFF users’ club.