THE INDUSTRIAL TITAN OF AMERICA 



,°>07 



when it is properly heated he gives it 

 back to the blower. Standing - over the 

 "swing hole," the blower allows the 

 weight of the plastic glass to elongate 

 the pear into a cylinder, which he gives 

 the desired diameter by blowing into it 

 intermittently. 



But, although it has reached the desired 

 diameter, the cylinder is not yet long 

 enough to suit his purpose. So he re- 

 heats it and blows it over and over again 

 until it attains the prescribed length. 



At this stage the cylinder is completed, 

 but the free end is closed and the 

 other end still adheres to the blowpipe. 

 It is put back into the blow furnace and 

 the free end heated until it is soft enough 

 to permit the blowing of a hole through 

 it. The resulting imperfect end is cut 

 away by wrapping a hot glass thread 

 around the cylinder above the imperfec- 

 tion, at the point of severance. Touched 

 with a piece of cold iron, the imperfect 

 section breaks asunder. The cylinder is 

 freed from the blowpipe in a similar man- 

 ner. 



We now have a perfect hollow cylinder 

 of regulation window glass. But before 

 it can be used in a window it must be flat- 

 tened. To accomplish this it must first be 

 split open. A hot iron or a charged elec- 

 tric wire, passed up and down the line 

 of cleavage, plays the role of a pair of 

 shears. It causes a strain-line to form 

 from one end of the cylinder to the 

 other, and when this is touched with a 

 piece of cold iron the big roll breaks open 

 as perfectly as though it were cut open 

 with a diamond cutter and straight-edge. 



After this the roll of glass is sent to the 

 annealing furnace. Heated to a proper 

 degree, the glass becomes soft enough to 

 permit the roll to be flattened. It is then 

 carefully cooled ai\d stored, ready for 

 market. 



MKCIIANICAL GENIUS A RKVOLUTIONIZKR 



By the hand-blowing process cylinders 

 up to as much as six feet long and nine- 

 teen inches in diameter can be blown. 

 Machine blowers have been gradually 

 substituted and have revolutionized the 

 art of making flat glass. All the larger 

 cylinders, such as are illustrated on pages 

 393 and 394, are machine blown. 



In simple terms a machine blower is an 

 apparatus which automatically dips a big 

 pipe into a kettle of molten glass, and 

 then gradually raises it, pulling all the 

 molten glass upward as the pipe rises. A 

 constant stream of air kept flowing in 

 through the pipe causes the glass to as- 

 sume the form of a cylinder. Dip a soda 

 straw into a thimbleful of molasses, and 

 blow through the straw as you lift it up 

 from the molasses— that process would 

 roughly duplicate the principle of the me- 

 chanical glass blower. 



It would be too long a story to tell in 

 this article the processes of making all 

 kinds of glass ; but it may be said that 

 when the machine for blowing bottles 

 came into use it changed the bottle in- 

 dustry as much as the mechanical blower 

 changed the window-glass industry. Ma- 

 chines have been invented for blowing 

 electric lamp bulbs also, but the hand 

 blowers are still able to produce a major 

 portion of these. 



When America went to war, there was 

 a dearth of optical glass in the country. 

 Germany had a monopoly thereon; but 

 Pennsylvania glass experts and the 

 United States Bureau of Standards set 

 to work on the problem, and today this 

 State is making as good optical glass 

 as is to be found anywhere. Hereafter 

 America will see the world through its 

 own spectacles and not through glass that 

 comes from overseas. 



One of the demands of the war was 

 for one-way glass, — glass that is trans- 

 parent from one side and opaque from 

 the other — being required for range-find- 

 ers and other optical instruments. It is 

 made by silvering one side, so that it 

 transmits exactly the same amount of 

 light that it reflects. There is a possi- 

 bility that such glass will ultimately be 

 used in architecture. With it the man- 

 ager of a big business could have an 

 office where he could work in privacy 

 and yet always be able to see what was 

 going on in the outer offices. 



One of the largest groups of factories 

 in America is that which comprises the 

 companies classified under the. general 

 head : Westinghouse industries. One of 

 these mammoth plants fabricates the air- 

 brake, to which the world owes a great 

 debt. It has equipped some three million 



