THE WORLD'S ADVANCE 



331 



ing side by side. The explanation is that 

 the crystals of the Iceland spar are so 

 formed that the ether contents of the 

 plate are of two distinct densities. Thus 

 the light attempts to penetrate either of 

 two different elasticities. The result is 

 the doubling of the image of the bulb as 

 seen through the spar. 



ELECTRICITY UNLOADS BANANAS 



In Texas, bananas are unloaded by 

 electricity. When the bananas arrive 

 from tropical ports it is necessary that 

 they reach their northern destinations as 

 promptly as possible, to prevent them 



SLOW SAFE-BREAKING 



The famous firm of Krupps over in 

 Essen, Germany, make more than "Jack 

 Johnsons" and "Busy Berthas." They 

 have now turned- out a brand new safe 

 which they guarantee to be burglar- 

 proof. While this is not strictly the 

 truth, inasmuch as burglars could break 

 into it, the conditions necessary for get- 

 ting into this safe are such that it is 

 doubtful if one of these safes could ever 

 be successfully burglarized. 



The reason is simple enough, for while 

 burglars can get into it with modern ap- 

 pliances, it would necessitate 50,200 

 pounds of liquid and six hours' work to 



Two Views of An Electric 

 Banana Unloader Used at 

 Various Texan Ports. The 

 Time Required for Unload- 

 ing a Fruit Ship is Les- 

 sened to a Very Great 

 Degree. 



from rotting. Electric unloaders are ac- 

 cordingly used, as they cut to an infini- 

 tesimal fraction the time formerly re- 

 quired by the picturesque man with a 

 wheelbarrow. 



make a hole large enough to permit the 

 entrance of a human hand! 



At a melting test, steel plates with a 

 surface of n.8 by n.8 inches and a 

 thickness of 1.57 inches were used, 

 which, in the separate testings, were sub- 

 jected for a different length of time to 

 an oxy-acetylene flame. At one of these 

 tests a hole of 1.968 inches diameter and 



1.377 inches depth was burned into the 

 plate, but for this not less than 476 gal- 

 lons of acetylene and 534 gallons of oxy- 

 gen were used, and the time consumed 

 was one and one-quarter hours. In order 

 to produce a hole large enough to admit 

 the hand, 2,642 gallons of oxygen and 



2.378 gallons of acetylene would be 

 needed, while the performance of this 

 work would require six hours. Conse- 



