Popular Science Monthly 



725 



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The Wind's Autograph on a Gusty Day 



Recorded with a pressure-tube anemometer. The vertical hnes are hour-hnes and the horizontal Hnes 

 show the force of the wind in miles an hour and dlso in pounds a square foot Direction is also indicated 



ground nor the character of the latter. 

 Many a forced landing in foggy weather 

 has ended disastrously in the ocean. 



The fog problem will undoubtedly be 

 solved. Probably the radio-compass or 

 some other system of wireless signalling 

 will help the airman keep his bearings, 

 and he will obtain further guidance from 

 aerial buoys, in the shape of captive 

 balloons, floating above the level of all 

 ordinary fogs. Mr. Holt Thomas, in 

 England, has recently proposed the plan 

 of establishing landing grounds at inter- 

 vals of a few miles along the main air 

 routes, their location to be marked with 

 kite-balloons by day and powerful search- 

 lights by night. A better plan would be to 

 fly at each landing place, and wherever 

 else aerial signposts were desired, a string 

 of kite-balloons flying tandem, with a 

 lantern suspended from each balloon. It 

 would thus be possible to attain much 

 greater altitudes than with a single balloon 

 and a searchlight, and hence to provide 

 for fogs of all depths. 



Little need be said about the other 

 weather factors in aviation, because they 

 are hardly more serious in their effects 

 than the corresponding conditions of 

 travel on ierra firma. At great altitudes 

 the air is very cold, in summer as well as 

 winter. The carbureter m.ust be shielded 

 against freezing, and the aviator needs the 

 warmest clothing. The airman also needs 

 protection against rain and hail — the 



pelting of which, when one is flying at one 

 hundred miles an hour or more, is un- 

 comfortable, to say the least. Lightning, 

 which is a serious hazard in ballooning, 

 seems to be relatively harmless to the air- 

 man Deposits of ice and snow, besides 

 loading the planes, may hamper the work- 

 ing gear of the machine, though aviators 

 have reported few cases of this kind. 



Last, but not least, in the coming age of 

 commercial aviation the weather bureau 

 now maintained by the governments of all 

 civilized countries will enlarge the scope 

 of their activities so as to safeguard air 

 traffic against atmospheric dangers; while 

 the science of weather will, in turn, derive 

 great benefit from the collective wisdom 

 of practical airmen. 



A Thousand Dentists Will Be in the 

 United States Army 



DENTISTS are just beginning to 

 come into their own in the Army. 

 Even yet their importance is insufficiently 

 recognized. According to the latest re- 

 ports we are to have only one dentist to 

 every thousand men. Yet there are to 

 be eight horseshoers to every hundred 

 horses. For the two hundred and fifty 

 thousand horses which the government 

 will need, there will twenty thousand 

 horseshoers, while for one million men 

 there will be provided only a thousand 

 dentists. 



Maybe you have special needs. Write to the editor about anything within the 

 scope of the magazine. He will be glad to help you. 



