﻿108 Canadian Record of Science. 



Neglect in care of this will cause extinction of the gas 

 -and discredit of the system. The gas companies have 

 -accustomed us to a constant supply through mains at an 

 -even })ressuie and liave set a high standard of conveni- 

 ence. 



The cylinders contain gas at a pressure of 6 to 700 lbs. 

 A reducing valve, always kept in order, must reduce this 

 pressure to 1 oz. = 2 inches water. The Pintch valve 

 employed on railroad lines is used, but we must ask the 

 question : Will it always keep in order with the care it 

 would get in a private house or tenement house ? Then 

 .an escape valve is recpiired in case a fault of the Pintch 

 valve throws the whole pressure on the pipes. A mercury 

 seal would answer to empty the gas into the air, and it 

 •coidd Ije counted on to work satisfactorily, but the gas 

 would be lost each time that the valves got out of order. 

 All this apparatus makes the use of liquefied acetylene 

 somewhat complicated, and in addition to this disadvan- 

 tage it would present a serious danger in case of fire. 

 The cylinders when strongly heated would be liable to 

 -explosion, and it is proposed to guard against this danger 

 by employing a mercury seal to empty them when the 

 pressure exceeds safe limits. This arrangement, even 

 .supposing that it always performed its office during a fire, 

 would be open to a serious objection, for if the fire took 

 place in a large building in a town containing, say, 10 

 cylinders with r),000 cu. ft. of gas in the 10, this quantity 

 of gas thrown in the air would make an explosive mixture 

 with 20 times its volume of air, or about 100,000 cu. ft. 

 in all, and whether disengaged on the roof or in the 

 street would expose the firemen to a new danger. 



If we add to the small annoyances arising from the 

 •care of a gas supply which is not constant like that of 

 -gas delivered in mains, the danger of explosion of a cylin- 

 •-der weakened by rust or neglect, the danger in case of 

 fire and the very doubtful economy of the systems, the 



