But, Ancram!鈥攚hat's the use? Why on earth should you fly off in this way? I'm sure it won't do! Do you suppose for an instant that Aunt Belinda will let you get at him? Although it has been little used for aircraft propulsion, the possibilities of the two-stroke cycle engine render some study of it desirable in this brief review of the various types of internal combustion engine applicable both to aeroplanes and airships. Theoretically the two-stroke cycle engine鈥攐r as it is more commonly termed, the 鈥榯wo-stroke,鈥?is the ideal power producer; the doubling of impulses per revolution of the crankshaft should render it of very much more even torque than the four-stroke cycle types, while, theoretically, there should be a considerable saving of fuel, owing to the doubling of the number of power strokes per total of piston strokes. In practice, however, the inefficient scavenging of virtually every two-stroke cycle engine produced nullifies or more than nullifies its advantages over the four-stroke cycle engine; in many types, too, there is a waste of fuel gases through the exhaust ports, and much has yet to be done in the way of experiment and resulting design before the two-stroke cycle engine can be regarded as equally reliable, economical, and powerful with its elder brother. 鈥淵ou see,鈥?resumed the monk, 鈥渢hat the love of silence and retirement is not common to all devout people; and that, as I was saying, this is the effect rather of their complexion than their piety. Those austere manners to which you refer are, in fact, properly the character of a savage and barbarian, and, accordingly, you will find them ranked by Father Le Moine among the ridiculous and brutal manners of a moping idiot. The following is the description he has drawn of one of these in the seventh book of his Moral Pictures. 鈥楬e has no eyes for the beauties of art or nature. Were he to indulge in anything that gave him pleasure, he would consider himself oppressed with a grievous load. On festival days, he retires to hold fellowship with the dead. He delights in a grotto rather than a palace, and prefers the stump of a tree to a throne. As to injuries and affronts, he is as insensible to them as if he had the eyes and ears of a statue. Honour and glory are idols with whom he has no acquaintance, and to whom he has no incense to offer. To him a beautiful woman is no better than a spectre; and those imperial and commanding looks 鈥?those charming tyrants who hold so many slaves in willing and chainless servitude 鈥?have no more influence over his optics than the sun over those of owls,鈥?&c.鈥?  看日本持A级毛片 In 1891 Mr Day invented a two-stroke cycle engine which used the crank case as a scavenging chamber, and a very large number of these engines have been built for industrial purposes. The charge of carburetted air is drawn through a non-return valve into the crank chamber during the upstroke of the piston, and452 compressed to about 4 lbs. pressure per square inch on the down stroke. When the piston approaches the bottom end of its stroke the upper edge first overruns an exhaust port, and almost immediately after uncovers an inlet port on the opposite side of the cylinder and in communication with the crank chamber; the entering charge, being under pressure, assists in expelling the exhaust gases from the cylinder. On the next upstroke the charge is compressed into the combustion space of the cylinder, a further charge simultaneously entering the crank case to be compressed after the ignition for the working stroke. To prevent the incoming charge escaping through the exhaust ports of the cylinder a deflector is formed on the top of the piston, causing the fresh gas to travel in an upward direction, thus avoiding as far as possible escape of the mixture to the atmosphere. From experiments conducted in 1910 by Professor Watson and Mr Fleming it was found that the proportion of fresh gases which escaped unburnt through the exhaust ports diminished with increase of speed; at 600 revolutions per minute about 36 per cent of the fresh charge was lost; at 1,200 revolutions per minute this was reduced to 20 per cent, and at 1,500 revolutions it was still farther reduced to 6 per cent. VIII AMERICAN GLIDING EXPERIMENTS It may be said that Louis Bleriot was responsible for the second great landmark in the history of successful flight. The day when the brothers Wright succeeded in accomplishing power-driven flight ranks as the first of these landmarks. Ader may or may not have left the ground, but the wreckage of his 鈥楢vion鈥?at the end of his experiment places his doubtful success in a different category from that of the brothers Wright and leaves them the first definite conquerors, just as Bleriot ranks as first definite conqueror of the English Channel by air.