Popular Science Monthly 



811 



A Wonderful New Glass Which 

 Cannot Be Shattered 



ANEW glass, transparent, tough 

 and strong, which has all 

 the advantages and none of 

 the defects of "brittle, fragile 

 window glass, has been in- 

 vented b\- Frank Shuman, 

 of Philadelphia, whose 

 earlier inventions in- 

 clude wire glass, a wide- 

 ly used form of con- 

 crete piling, and the 

 sun power plant erect- 

 ed at Maadi, near 

 Cairo, Eg\-pt. 



A twent>'-two cali- 

 lier bullet cannot pene- 

 trate the new glass; a 

 brick cannot shatter 

 it; a heaxT,' man thrown 

 against it under all the 

 terrific momentum of a 

 collision would not go 

 through it, but would 

 be thrown back from 

 it, uninjured by flying 



A sharp blow with a hammer may crack 

 the glass but will not shatter it into splinters 



glass, because none would fly. A stone 

 i irown against it will bounce back like a 

 golf ball. 



When struck a powerful blow, as 

 with a hammer, for instance, it 

 will crack into hair lines, as 

 shown in the accompa- 

 nying illustration, but 

 there will be no shower 

 of flying glass or splin- 

 ters. Furthermore, 

 these hair-line cracks 

 leave the surface abso- 

 lutely smooth. 



The secret of its 

 strength is a sheet of 

 white, transparent cel- 

 luloid, t w e n t y - o n e 

 thousandths of an inch 

 thick, which is placed 

 between two pieces of 

 glass. The glass and 

 celluloid are simply 

 welded together under 

 high temperature and 

 tremendous pressure, 

 the resultant being a 

 solid sheet possessing all the 

 transparency of the best plate 

 glass, combined with the 

 strength of a sheet of metal. 



• I 



A boiler can be blown clean in six minutes. If cleaned once 

 in every six hours it will increase five per cent in efficiency 



Preventing Boiler Troubles by 

 Mechanical Cleaning 



THE shortcomings and diffi- 

 culties connected with the 

 hand-cleaning of modern steam- 

 boilers have resulted in the de- 

 velopment of the mechanical 

 steam-blower, the latest and 

 most effective type of which is 

 shown in the illustration. It 

 employs nozzles arranged across 

 the width of the boiler, so that 

 all surfaces are equally accessible 

 and soot cannot be blown from 

 one part of the boiler to another. 

 Two cleaner-elements are 

 mounted on bearings and ro- 

 tated by a chain and sprocket- 

 wheel outside the setting. The 

 jets of steam are directed 

 along diagonal paths, one in 

 one direction and the other 

 in the opposite direction. 

 When the}' are discharged into 

 the passages between the tubes, 

 the cleaner is slowly rotated, 

 back and forth over a wide arc. 



