Years afterwards Nasmyth returned the visit, and saw in the Creusot Works a crank-shaft so large that he asked how it had been forged. "By means of your steam hammer," came the reply. You may imagine Nasmyth's surprise on finding the very machine at work in France which his own countrymen had so despised, and his delight over its obvious success.
On returning home he at once raised money enough to secure a patent, protected his invention, and began to manufacture what has been described as "one of the most perfect of artificial machines and noblest triumphs of mind over matter that modern English engineers have developed." A few weeks saw the first--a 30-cwt.--hammer at work. People flocked to watch its precision, its beauty of action, and the completeness of control which could arrest it at any point of its descent so instantaneously as to crack without smashing a nut laid on the anvil. "Its advantages were so obvious that its adoption soon became general, and in the course of a few years Nasmyth steam hammers were to be found in every well-appointed workshop both at home and abroad."[7]
Nasmyth's invention was improved upon in 1853 by Mr. Robert Wilson, his partner and successor. He added an automatic arrangement which raised the "tup," or head, automatically from the metal it struck, so that time was saved and loss of heat to the ingot was also avoided. The beauty of the "balance valve," as it was called, will be more clearly understood if we remember that the travel of the hammer is constantly increasing as the piece on the anvil becomes thinner under successive blows. Under the influence of this very ingenious valve every variety of blow could be dealt. By simply altering the position of a tappet lever by means of two screws, a blow of the exact force required could be repeated an indefinite number of times. "It became a favourite amusement to place a wine-glass containing an egg upon the anvil, and let the block descend upon it with its quick motion; and so nice was its adjustment, and so delicate its mechanism, that the great block, weighing perhaps several tons, could be heard playing tap, tap upon the egg without even cracking the shell, when, at a signal given to the man in charge, down would come the great mass, and the egg and glass would be apparently, as Walter Savage Landor has it, 'blasted into space.'"[8]