Slide rules could make a comeback in mathematics classes, according to an engineering lecturer at Potenza University, in southern Italy.

Giovanni Pastore, 50, believes students would benefit from using slide rules, alongside calculators and computers, because it makes them learn to think.

He also wants to preserve knowledge of how these instruments are used and is preparing a 600-page book covering general-purpose mathematical rules and the many specialist models designed for mechanics, chemistry, topography, electricity, reinforced concrete, navigation, aviation, commerce and other areas.

Professor Pastore said: "Today's students pull out their calculator to divide or multiply by ten. A slide rule encourages the student to think, rather than just press buttons. This develops the student's grasp of the subject.

"Television has not made radio obsolete, nor have cars universally replaced horses or bicycles. In some kinds of calculations there are distinct advantages to using a slide rule. Of course, precision is limited compared with a calculator, but inaccuracies of less than 0.5 per cent are negligible for most practical purposes."

Bruno Bassan, 47, a mathematician at Rome's La Sapienza University, said:

"Professor Pastore's idea sounds a little like asking people to ride a horse while taking driving lessons. It is a nice idea, but perhaps more for amusement than for serious inclusion in university studies."

Professor Pastore graduated from Turin Polytechnic in 1978. He worked at Fiat for two decades before turning to freelance civil engineering and teaching, first at Cosenza University and now at Potenza.

He has almost 300 slide rules in his collection and has helped to set up a slide rule section in the Mathematical Museum at La Sapienza. There, the rules are displayed alongside an early edition of John Napier's book on logarithms, which paved the way for the slide rule.

Professor Pastore's website is very popular with academics and slide-rule collectors. Among other things, it shows photographs of scientists Wernher von Braun and Sergei Korolev with their favourite slide rules.

Details: www.giovannipastore.it