Philarete Chasles, indeed, holds that it is the Human Race that is your true inventor: "As if to unite all generations," he says, "and to show that man can only act efficiently by association with others, it has been ordained that each inventor shall only interpret the first word of the problem he sets himself to solve, and that every great idea shall be the RESUME of the past at the same time that it is the germ of the future." And rarely does it happen that any discovery or invention of importance is made by one man alone. The threads of inquiry are taken up and traced, one labourer succeeding another, each tracing it a little further, often without apparent result. This goes on sometimes for centuries, until at length some man, greater perhaps than his fellows, seeking to fulfil the needs of his time, gathers the various threads together, treasures up the gain of past successes and failures, and uses them as the means for some solid achievement, Thus Newton discovered the law of gravitation, and thus James Watt invented the steam-engine. So also of the Locomotive, of which Robert Stephenson said, "It has not been the invention of any one man, but of a race of mechanical engineers." Or, as Joseph Bramah observed, in the preamble to his second Lock patent, "Among the number of patents granted there are comparatively few which can be called original so that it is difficult to say where the boundary of one ends and where that of another begins." The arts are indeed reared but slowly; and it was a wise observation of Lord Bacon that we are too apt to pass those ladders by which they have been reared, and reflect the whole merit on the last new performer. Thus, what is hailed as an original invention is often found to be but the result of a long succession of trials and experiments gradually following each other, which ought rather to be considered as a continuous series of achievements of the human mind than as the conquest of any single individual. It has sometimes taken centuries of experience to ascertain the value of a single fact in its various bearings. Like man himself, experience is feeble and apparently purposeless in its infancy, but acquires maturity and strength with age. Experience, however, is not limited to a lifetime, but is the stored-up wealth and power of our race. Even amidst the death of successive generations it is constantly advancing and accumulating, exhibiting at the same time the weakness and the power, the littleness and the greatness of our common humanity. And not only do we who live succeed to the actual results of our predecessors' labours,--to their works of learning and of art, their inventions and discoveries, their tools and machines, their roads, bridges, canals, and railways,--but to the inborn aptitudes of blood and brain which they bequeath to us, to that "educability," so to speak, which has been won for us by the labours of many generations, and forms our richest natural heritage.