38 



ble for the increase ; at any rate, it would seem that when small 

 pipes have been in the ground for many years with thread joint con- 

 nections, there is much less leakage than if larger pipes are used 

 and the calking done with oakum and cement or lead. 



The trolley, steam roller and other heavy traffic on highways are 

 in part responsible for defective joints, and occasionally cause leak- 

 age of gas. The continual excavation and undermining of gas con- 

 duits made necessary by the construction of sewer and water lines, 

 as well as the effects of frost in severe seasons, also cause leakage, 

 and finally the modern network of wires, steel rails, etc., which carry 

 electricity, are a constant source of danger to gas pipes, as is occa- 

 sionally proved by cases of electrolysis. 



Fig. 18. Showing flexible shaft and gasoline engine arranged for 

 cleaning cavities. 



A large amount of the gas manufactured is unaccounted for. Ac- 

 cording to the twenty-tirst annual report of the Gas and Electric 

 Light Commissioners of Massachusetts, the production of gas for the 

 year 1905 in this State was 6,418,024,954 cubic feet. The amount 

 unaccounted for during that year was 622,304,044 cubic feet; in 

 other words, there was a loss of about 10 per cent. This loss un- 

 doubtedly represents more than mere leakage, however, since part of 

 it may be accounted for by differences in temperature to which the 

 gases are subjected when measured. 



It should be stated, in justice to many of the larger man- 

 ufacturers of gas in this State that every effort is made to pre- 



