. The railroad and engineering journal . grains. . .Thirty or 40 copies of the microscopic despatches were usu-ally printed and sent by as many pigeons. More than 100,000of them were thus sent to Paris during the siege. As soon asthe small lube was received at the telegraph office, MM. Corunand Mercadier proceeded to open it with a knife. The photo-graph fdnis were carefully placed in a small basin of water, inwhich were put a few drops of ammonia. In this liquid thedispatches unrolled themselves. They were then dried andplaced between two plates of glass. It then only remained tolay them on t
. The railroad and engineering journal . grains. . .Thirty or 40 copies of the microscopic despatches were usu-ally printed and sent by as many pigeons. More than 100,000of them were thus sent to Paris during the siege. As soon asthe small lube was received at the telegraph office, MM. Corunand Mercadier proceeded to open it with a knife. The photo-graph fdnis were carefully placed in a small basin of water, inwhich were put a few drops of ammonia. In this liquid thedispatches unrolled themselves. They were then dried andplaced between two plates of glass. It then only remained tolay them on the stage plate of a photo-electric microscope. Automatic Fog Signal.—The accompanying illustrationsshow a fog signal apparatus devised by Robert Adams andStanhope A. Say, of London, which is now being introducedin England. Fig. i shows the apparatus arranged at the sideof the track, and fig. 2 is the distant arm. As will be seen from fig. i, two sets of three turrets arearranged on an iron foundation, each cylinder being capable of. passes from each car to the foot of the incline, around the ten-sion sheaves, and returns to the other car, thus attaching bothto an endless cable, whose direction of motion is reversed forevery trip. The slack of the cable is taken up by a movabletension carriage at the foot of the incline, which works againststiff springs, and has a travel of about 3 ft. Provision for hold-ing the cars in the event of a break of the cable includes a sectorbrake-shoe, which falls under the wheels and into which thewheels roll, forcing down a V-shaped grip upon the of this brake show that it will hold the cars motionlesson the steepest portion of the incline. To prevent danger frompossible over-winding, the upper extension of each track endsin a level piece of track, the end of which is on level ground,from which the cars cannot return to the rails unaided. Thetrip over the incline occupies about three minutes. Photography in War.—A writer on th
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
