One objection to the machine is the difficulty of learning, which is considerable, but which presents no danger. This difficulty has been much exaggerated, for before the present powerful brake was applied it did require considerable skill to ride it down a steep hill. The way to do this must still be learnt, but it is now comparatively easy. For going down steep hills, the front steering tricycle is without a rival; I do not know what other machine will do this better than the Otto. Lastly, the foot straps, which would be a great advantage on any machine, if only they were safe, are not--though none but riders will believe it--in any way a source of danger on the Otto. Having ridden this machine for close upon 10,000 miles, I can speak with more authority on this point than can those who are not able to sit upon it for a moment. The only disadvantage which the machine presents is the fact that it is impossible to remove the feet from the pedals while running, without dismounting; but though they must at all times follow the pedals, the Ottoist is not, as is generally thought, working when descending a hill. The enthusiastic terms in which every one who has mastered the peculiarities of the Otto speaks of it would be considered as evidence in its favor, if we were not all considered by other cyclists to be in various stages of lunacy. * * * * * THE CANAL IRON WORKS, LONDON. Some interest is awakened in engineering circles in London, just now, by the approaching close of the old engineering works so well known as the "Canal Ironworks," at the entrance to the Isle of Dogs, London, E. This notable establishment stands second in priority in London--that of Messrs. Maudslay, Sons & Field being the oldest--for the manufacture of marine engines. It was founded by the late Messrs. Seawards, above sixty years ago. Here was originated Seaward's hoisting "sheers" with the traveling back leg, a modern example of which, 100 feet high, in iron, stands on the wharf. An interesting tool, also, is the large vertical boring machine for largest size cylinders; Seaward spent £5,000 upon this, and it is certainly an admirable tool. There is also the large vertical slotting machine, with a stroke up to 5 feet 2 inches, a wonderfully powerful and compact machine. The extensive collection of screwing tackle is, perhaps, unsurpassed, and extends up to 8 inches diameter. There is a peculiar erecting shop roof, which will still repay examination. * * * * * MARINONI'S ROTARY PRINTING PRESS. The greatest progress that has been made in recent years in the art of printing is in the invention of the high speed press provided with continuous paper.