752 



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 



