John Marlow, of Christchurch, asks :-

When ordering a beer in craft beer and other pubs, I usually ask for a pint. The glasses I am given vary dramatically in size. Is there a standard?

John Campbell, a physicist at the University of Canterbury who taught a course on "Measurement Standards", responded.

In this country, not officially.

New Zealand metricated in the late 1960s for the best of reasons. One is shown by the question in mathematics that 11-year-old Ernest Rutherford had to pass for promotion into the next class at primary school. "How many drams are there in 35 tons17 cwt 1 qr 23 lbs 7 oz 13 drams?" Every stage involved a different number, rather than just multiples of 10.

Another was that by the 1700s towns had developed their own standards of mass, length and volume. As trade expanded to other towns and countries, there had to be national then international standards established.

After independence, the USA defined its volume measurement on one of the gallon measurements then in use. Thus it and the metric "litre" (France) both predate the Imperial gallon standard which was standardised later in 1842. The difference between the USA gallon and the Imperial gallon is roughly that an oil drum (200 litres) was our, just under, 44 gallon drum (Imperial) that held nearly 53 US gallons.

In New Zealand it is illegal to advertise goods in other than metric quantities, and for good reason. A pint is an eighth of a gallon. As a member of SOBA (the Society of Beer Advocates), our equivalent of England's CAMRA (Campaign for Real Ale), I am used to bars which specialise in craft beers pricing by the pint. The genuine ones will qualify that by "Imperial pint" or "(568ml)". Dodgy ones may use the American pint for which one receives only 88 per cent of the Imperial measure. Regular hotels may pick a glass of indeterminate measure when a patron asks for a "pint".

I remember when one student took on a project of determining the volume of a "nip of spirits" in bars around town. These varied greatly in volume. One way of having a fixed price for nips of spirits for which the price per bottle varies widely, is the "fixed volume" sight glass attached to the tops of bottles. The volume dispersed can be reduced by inserting "invisible" glass cylinders into the sight glass, thus making the "nip" of different spirits the same price but different volumes.

It is a pity that the USA didn't adopt the metric system when they had a chance in Congress in 1900, or at some other later times. They dominate aircraft manufacturing hence civil aviation in the Pacific still use feet for altitude. And we need to assassinate all grannies, so that NZ can get rid of the last vestiges of the old Imperial measurements and new mothers, now born decades after this country metricated, can report the mass of their new babies in kgs, not pounds.