Consider These Miracles of Mechanics and Think 



The device pictured on 

 the right has robbed 

 bursting water mains 

 of their terror. The 

 mechanically operated 

 valve-closing apparatus 

 is mounted on the run- 

 ning board. Below will 

 be seen two pictures 

 showing an electric 

 truck used in Phila- 

 delphia for trimming 

 arc lights 



900 



