Another fertile source of variation arises from errors in successive copies. At a time when men had no measures or other appliances to assist them in copying correctly, and were guided only by the eye, an implement would soon be made to assume a very different appearance. Mr. Evans has shown in his work on the ‘Coins of the Ancient Britons’ (p. 167) how the head of Medusa, copied originally from a Greek coin, was made to pass through a series of apparently meaningless hieroglyphics, in which the original head was quite lost, and was ultimately converted into a chariot and four. We must not, however, attribute all variation to this cause, for I quite agree with a remark made by Mr. Rawlinson in his ‘Five Great Monarchies’, that such varieties are more frequently noticed in cases where the contrivance is of home growth, than in those which are derived from strangers.
The third point which we shall have to consider in relation to continuity, is the retarding element. Under this head, incapacity must at all times, and especially in the infancy of society, have played the chief part. But as civilization progressed, other agencies would come in to influence the same result; prejudice, force of habit, principles of conservatism in which we have been told by Mr. Mill that all the dull intellects of the world habitually ensconce themselves, a thousand interests of a retarding tendency, rise up at the same time as those having a progressive influence, and prevent our advancing by other than well-measured paces.
The resultant of these contending forces is continuity. If we could but put together the missing links; if we could revive contrivances that have died at their birth, and expose piracies; if we could penetrate the haze that is so often thrown over continuity by great names, absorbing to themselves the credit of contrivances that belong to others, and thereby causing it to appear that progress has advanced with great strides, where creeping was in reality the order of the day; we should find that there is not a single work of man’s hand which has not its history of slow and continuous development, capable of being traced back, like branches of a tree, to its junction with others, and so on until the roots of all are found to lie in the simplest contrivances of primaeval man.