鈥楾he first subject for consideration is the proportion of surface to weight, and their combined effect in descending perpendicularly through the atmosphere. The datum is here based upon the consideration of safety, for it may sometimes be needful for a living being to drop passively, without muscular effort. One73 square foot of sustaining surface for every pound of the total weight will be sufficient for security. When Diamond had gone, the old man sent for his daughter to come to him in the parlour. "You can take yourself off, Betty Grimshaw," said he to that respectable spinster, very unceremoniously. "You and James can bide in the kitchen till supper's ready. When it is, come and tell me." Gradually Brooks led around to more intimate subjects and finally the name of Rascon was mentioned. 2019最新国产不卡a|日本无吗无卡v清免费|在线视频播放 There! she exclaimed, with a little despondent gesture of the head, "you were speaking and looking kindly, and I have driven you away! I wish I was dead." 鈥業n order that the description hereafter given may58 be rendered clear, I will first shortly explain the principle on which the machine is constructed. If any light and flat or nearly flat article be projected or thrown edgewise in a slightly inclined position, the same will rise on the air till the force exerted is expended, when the article so thrown or projected will descend; and it will readily be conceived that, if the article so projected or thrown possessed in itself a continuous power or force equal to that used in throwing or projecting it, the article would continue to ascend so long as the forward part of the surface was upwards in respect to the hinder part, and that such article, when the power was stopped, or when the inclination was reversed, would descend by gravity aided by the force of the power contained in the article, if the power be continued, thus imitating the flight of a bird. Consequently, a safety track was provided, consisting of squared pine logs, three inches by nine inches, placed about two feet above the steel way and having a thirty-foot gauge. Four extra wheels were fitted to the machine on outriggers and so adjusted that, if the machine should lift one inch clear of the steel rails, the wheels at the ends of the outriggers would engage the under side of the pine trackway. For dirigibles, balloons, and kite balloons the parachute is an essential. It would seem to be equally essential in the case of heavier-than-air machines, but this point is still debated. Certainly it affords the occupant of a falling aeroplane a chance, no matter how slender, of reaching the ground in safety, and, for that reason, it would seem to have a place in aviation as well as in aerostation. 鈥業n all its main features the hull structure of R.33 and R.34 follows the design of the wrecked German Zeppelin airship L.33. The hull follows more nearly a true stream-line shape than in the previous ships constructed of duralumin, in which a greater proportion of the greater length was parallel-sided. The Germans adopted this new shape from the Schutte-Lanz design and have not departed from this practice. This consists of a short, parallel body with a long, rounded bow and a long tapering stem culminating in a point. The overall length of the ship is 643 feet with a diameter of 79 feet and an extreme height of 92 feet.