During the second half of the nineteenth century the Rev. J. G. Wood did more than anyone to popularise natural history in Britain. Among the scores of books he wrote about animals and their activities was Nature’s Teachings. First published in 1876, it deals with one of his favourite subjects: how the works of nature have anticipated many of the inventions of man. He shows, for instance, how animals had long preempted the invention of the spear, the gun, the hook, the saw, the sail and the rudder. He points out that we borrowed from the lower animals our first idea of a dwelling, adding that ‘not only primitive ideas of Architecture are to be found in Nature, but that many, if not all, modern refinements have been anticipated.’
Tunnels fascinated him and he gives several examples showing how some of those constructed by man have their counterparts in structures made by birds, insects - and molluscs. He even goes so far as to say that it was the Shipworm (Teredo navalis) which helped Sir Marc Isambard Brunel (father of Isambard Kingdom Brunel) solve the problem of how to bore a tunnel through the loose, sandy soil under the River Thames, a statement based, apparently, upon fact.
‘The plan adopted by the Ship-worm’, he says, ‘is at the same time simple and effective. It feeds upon wood, and gradually eats its way through almost any timber that may be submerged. It does not, however, merely bore its way through the timber, but lines its burrow with a coating of hard, shelly material. Taking this hint, Brunel proceeded in the same fashion to drive his tunnel through the very ungrateful soils which form the bed of the Thames. He built a “shield,” as he called it, of iron, exactly fitting the tunnel, and divided into a number of compartments, each of which could be pushed forwards independently of the others. In each compartment was a single workman, and, as he excavated the earth in front of him, he pushed forward his portion of the shield, while the interior was cased with brickwork, just as a Teredo tunnel is cased with shell.’
We recognise the genius of a distinguished engineer who successfully bored a tunnel below the River Thames between 1825 and 1843, but we should also acknowledge his debt to the tunnelling activities of the humble Shipworm. Well might the Rev. J. G. Wood say, in the Preface to Nature’s Teachings, ‘There is scarcely an invention of man that has not its prototype in Nature.’