Page:Popular Science Monthly Volume 91.djvu/768

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��Popular Science Monthly

���A touch of an electric button ignites the powder. It flares up and lights up the surrounding country

��Making a Safe Landing at Night From an Airplane

���A 1

��N aviator so unfortu- nate as to have his engine go back on him while flying along at night is in a precarious position. Until recently, there was nothing for him to do but to trust to luck and de- scend.

By the invention of Har- old E. S. Holt, of England, however, the extreme danger of such a posi- tion is mitigated. The principal feature of his device is a long steel arm which hangs down from the airplane. This is a flood-lighting arrangement. You' press an electric but- ton; the powder held at the end of the steel arm is thus ignited. This powder is the sort of stuff which mariners use in signal- ing in stormy weather; a powder which burns long and with an intense flame. Thus the landscape below the airplane is lighted up so that you can see plainly to choose a landing place which promises a fair degree of safety.

��Sorting Letters with Gravity Chutes in the Post Office

IN a large city post office where millions of letters' a day are received, the problem of sorting them usually requires a staff of men nearly as large as that necessary to deliver the letters about the city. To reduce the expense of sorting, William G. Axworthy, of Montclair, New Jersey, has designed a sorting case by which the letters can be sorted in about one-half the time usually required. The case con- sists of five horizontal rows of very narrow compartments, all close together. The pile of letters to be sorted is placed in a hori- zontal position at the level of the middle row of slots. The prac- ticed eye of the sorter can recog- nize the town where the top letters are to go just as quickly as the letters can be uncovered. Due to the close proximity of the slots, the letters can be thrown into the respective compartments assigned to them at the same high speed. How different is the old system where the slots are deep and must be built over five vertical feet of wall space! No longer is motion lost in reaching down to the slots near the floor. This operation is effected by little chutes in back of each slot. The letters fall down these chutes into the larger storage compartments below.

��Details of the device for flood- lighting the land directly beneath the a i r p la n e

���Hinged Stop

��The letters for the lower compartments are dropped into slots and carried down by gravity

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