Photograph courtesy Philadelphia Commercial Museum 



REMOVING THE WASTE ENDS OF CYLINDERS, ONE OF THE OPERATIONS IN THE 

 MANUFACTURE OF WINDOW GLASS 



A cylinder of glass having been blown to the proper thickness and length, both ends are 

 snapped off. A hot iron or electric wire is then passed along one side from end to end. The 

 application of a cold iron to this heated streak causes the glass to crack, after which the 

 cylinder is ready to be softened by heat and flattened into sheet glass. 



of hot. putty-thick glass. A big mechan- 

 ical rolling pin spreads it out, after which 

 it hardens. Then it is sent to the anneal- 

 ing furnace, heated, and allowed to cool 

 gradually, for cooling either too fast or 

 too slow would be ruinous. Finally it is 

 ground down and polished and is ready 

 for shipment. 



FROM SOUP TO WINDOW GLASS 



The process of making blown window 

 glass is entirely different. In hand-blow- 

 ing, after the batch has been melted, the 

 ''gatherer'' takes a pipe about rive feet 

 long, with a bell-shaped head at one end 

 and a mouthpiece at the other, and dips 

 the bell-shaped end into the molten glass. 

 A small ball of the glass adheres. He 

 blows through the pipe and transforms 

 this ball into a thick-skinned bubble. 

 \\ 'hen this cools sufficiently it is dipped 

 into the molten glass again, and more ad- 



heres. The process is usually repeated 

 rive times, the bubble growing thicker of 

 skin each successive time ( see page 30,2 ) . 



The pipe, with its adhering plastic bub- 

 ble, is then given to a ''snapper,'' or 

 helper, who carries it to the ''blower's 

 block,'' where the "blower" takes it. The 

 latter workman is the king bee of the 

 glass industry — big of body, powerful of 

 lung, and deft of hand. He places the 

 bubble in the "block," which is an iron 

 mold set in water to prevent its becoming 

 too hot. and lined with charcoal to keep 

 the iron from discoloring the glass. 



By turning the bubble in the block, 

 blowing air into it as he does so. and 

 gradually drawing the pipe upward, he 

 slowly transforms it into a pear- 

 shaped affair. The lower part gradually 

 becomes solid and too hard to be work- 

 able even with his powerful lungs. The 

 snapper puts it into the blow furnace, and 



395 



