THE present excavation in front of the Museum is prevented from collapsing by a wall of interlocking steel piles. These were installed by a remarkable machine, the Giken Silent Piler, first developed in Japan about twenty-five years ago.
Essentially a powerful hydraulic ram, the Silent Piler forces 10 metre piles into the ground with a force of up to 150 tonnes. It can operate in constricted spaces since it walks along the top of the piles it has just driven, turning corners if necessary.
Such heavy engineering may seem remote from the refined world of scientific instruments, but careful consideration shows it to be much closer than expected. In the Museum are in fact several pile-drivers already, including the example above. The example is made of mahogany with brass fittings, and is a half inch to the foot model of the pile-driver used in the construction from 1738 to 1750 of the new bridge at Westminster and invented by James Vauloue.
In operation, the ram of the pile-driver was raised by a capstan turned by three horses, and was automatically released every time it reached the top of its travel. It weighed about 1 ton and was dropped 30 feet. As the horses continued rotating the capstan, a ‘follower’, which descended slowly behind the main ram, gripped it and raised it to the top once more.
Very little is known about Vauloue, except that he called himself a watch-maker, and that he won the Royal Society Copley Medal for his work on the pile-driver. However, as it happens the Museum has in its collection a fine gilt brass and silver mechanical equinoctial dial signed ‘I: VAULOUE / LONDON’ – evidence of the extremities of scale at which engineers of the period could operate.
Desaguliers, the leading teacher of experimental philosophy of the time, included a very fine engraving of Vauloue’s pile-driver in his book A Course of Experimental Philosophy published in 1744. Models of the machine also became a standard part of the demonstration kit of lecturers in this field, who usually had many different contrivances for illustrating the key mechanical principles, as well as distinctive models of real devices.
The model of the pile-driver in the Museum was made in about 1750 by the well-known instrument maker Benjamin Cole of Fleet Street. Cole’s father, also named Benjamin, brings us back full circle to Oxford, since he was a surveyor in the city and lived in a house which overlooked the site of the recent piling. –
