Clement was a heavy-browed man, without any polish of manner or speech; for to the last he continued to use his strong Westmoreland dialect. He was not educated in a literary sense; for he read but little, and could write with difficulty. He was eminently a mechanic, and had achieved his exquisite skill by observation, experience, and reflection. His head was a complete repertory of inventions, on which he was constantly drawing for the improvement of mechanical practice. Though he had never more than thirty workmen in his factory, they were all of the first class; and the example which Clement set before them of extreme carefulness and accuracy in execution rendered his shop one of the best schools of its time for the training of thoroughly accomplished mechanics. Mr. Clement died in 1844, in his sixty-fifth year; after which his works were carried on by Mr. Wilkinson, one of his nephews; and his planing machine still continues in useful work. [1] On one occasion Galloway had a cast-iron roof made for his workshop, so flat and so independent of ties that the wonder was that it should have stood an hour. One day Peter Keir, an engineer much employed by the government--a clever man, though some what eccentric--was taken into the shop by Galloway to admire the new roof. Keir, on glancing up at it, immediately exclaimed, "Come outside, and let us speak about it there!" All that he could say to Galloway respecting the unsoundness of its construction was of no avail. The fact was that, however Keir might argue about its not being able to stand, there it was actually standing, and that was enough for Galloway. Keir went home, his mind filled with Galloway's most unprincipled roof. "If that stands," said he to himself, "all that I have been learning and doing for thirty years has been wrong." That night he could not sleep for thinking about it. In the morning he strolled up Primrose Hill, and returned home still muttering to himself about "that roof." "What," said his wife to him, "are you thinking of Galloway's roof?" "Yes," said he. "Then you have seen the papers?" "No--what about them?" "Galloway's roof has fallen in this morning, and killed eight or ten of the men!" Keir immediately went to bed, and slept soundly till next morning. [2] See more particularly The Transactions of the Society for the Encouragement of Arts, vol. xxxiii. (1817), at pp. 74, 157, 160, 175, 208 (an admirable drawing; of Mr. James Allen's Theodolite); vol. xxxvi. (1818), pp. 28, 176 (a series of remarkable illustrations of Mr. Clement's own invention of an Instrument for Drawing Ellipses); vol. xliii. (1825), containing an illustration of the Drawing Table invented by him for large drawings; vol. xlvi. (1828), containing a series of elaborate illustrations of his Prize Turning Lathe; and xlviii. 1829, containing illustrations of his Self-adjusting Double Driver Centre Chuck.