Popular Science Monthly 67 



Bubbles in the Blood Kill Many No Trouble if This Mirror Drops. It 

 a Poor Soldier Is of Indestructible Steel 



SOLDI 

 found 



ERS are 



A small steel mirror for the trenches. 

 With it a soldier can shave perfectly 



the battlefield, with 

 no mark of an injury. 

 Some are Ijnng with 

 arms outstretched as 

 in running; others 

 are grasping their 

 guns as though about 

 to fire — all are in ex- 

 actly the positions in 

 which they were at 

 the moment of death. 

 These mysterious 

 deaths do not occur 

 as a result of nervous 

 shock; else the bod- 

 ies would be relaxed 

 and natural. They 

 are victims of "the 

 bends" or "caisson 

 disease" caused by 

 sudden release from 

 great air-pressure. 



When a workman 

 emerges from a high- 

 pressure air chamber, his blood fills with 

 small bubbles, like those of champagne 

 when first uncorked. If the bubbles are 

 large enough to choke the circulation, the 

 man dies. On the battlefield, such occur- 

 rences are the result of 

 intense explosion- 

 waves. The blood 

 holds in solution a con- 

 siderable amount of air 

 and carbon dioxide, 

 the quantities being 

 greater when the 

 pressure is high. 



Upon lowering the 

 pressure, the gases sep- 

 arate out as bubbles. 

 In the case of soda 

 water, the bubbles can 

 escape, but in a man 

 they are caught in the 

 capillaries. All mus- 

 cular action is arrested 

 with lightning-like 

 rapidity, thus preserv- 

 ing the attitude held 



by the victim before just rub the tobacco off the 



the fatal attack. windshield with a clean cloth 



A THREE by four 

 inch mirror, 

 which is intended 

 especially for use in 

 the trenches, is made 

 of a special metal 

 which contains a 

 high percentage of 

 nickel. It will neither 

 rust not corrode. 



The surface of the 

 metal is highly pol- 

 ished and reflects al- 

 most as well as glass. 

 It is protected by a 

 soft lined case into 

 which it fits. 



It is usually car- 

 ried in the upper left 

 hand coat pocket, 

 where it does excel- 

 lent service as a 

 shield, being suffi- 

 ciently strong to di- 

 vert glancing bullets. 



Chewing-Tobacco to Clear \^ ind- 

 shields! Would You Believe It? 



WHILE inventors are trying to devise 

 something that will effectually pre- 

 vent the fogging of 

 automobile wind- 

 shields in rainy weath- 

 er, along comes Theo- 

 dore Petersen, a drug- 

 gist in Grand Rapids, 

 Michigan, with a plug 

 of ordinary chewing 

 tobacco and solves the 

 whole problem! 



Not only does 

 the tobacco prevent 

 the windshield from 

 fogging, he says, but 

 it enables the rain 

 water to run off the 

 glass without collect- 

 ing in drops. After 

 each application it is 

 only necessary to rub 

 off the glass with a 

 cloth to remove all 

 marks of the tobacco. 



