DEAR SIR,

ENGINEERS measure everything that moves so as one I'm naturally a great admirer of the metric system. Our imperial measurements could have been written by Monty Python. Just for lengths alone we start with inches then move through feet, yards, chains, furlongs until we finish with our mile Worse still each conversion factor is not decimal (10) but is different 12 for inches to feet, 3 for feet to yards, then a 22, a 10 and finally an 8 to make a mile – confused? And that's just on land, at sea it all changes! The metric system is so logical, easy to use and understandable except for rainfall when it uses volumes instead of depths. Just this week on Tuesday we had headlines “Rain causes Chaos” with the island on level one yellow alert expecting 20 mililitres per square metre – 20 what? Is this a lot or a little? Presumably it's a lot to warrant an alert. On Wednesday “Majorca and Minorca pay Price of Storms” with Palma reputedly copping 1113 litres per square metre and that seems much more than 20 mililitres but can you visualize what it entails? I had absolutely no idea what this signified until I saw the photos.

The downpour where I live added 5 inches (12 cms) to the pool and almost overflowed it. That I can understand. Not its equivalent 120 litres. Even more dubious is the 20 mililitres at 2 mm barely visible nor 1113 litres or 1.113 m (nearly 4 feet) seems too much. This is exactly the problem the litre values are virtually meaningless while the depth measurement is understandable and immediately throws the figures into doubt. Misunderstandings can be costly. In 1999 (Arab decimal numerals or MCMXCIX in our earlier Roman system) the Mars Orbiter costing $125 million went way off course and was lost because NASA used Metric measurements (metres. kilometres) and assumed the manufacturer Lockheed did likewise. They used our antiquated Imperial (feet, miles) assuming NASA did as well.

Mike Lillico, Playa de Palma