OPERATIONS. ?3 



to buy from two or more different districts, according to the 

 fluctuations of the market. In any case, it is a convenience 

 to have two different qualities of coal in store, giving a 

 marked difference in the yield of gas, as affording means 

 for varying the make per charge. At Christmas, or at other 

 times when there is a full demand for gas, the better kind 

 may be used exclusively. In light weather, or on early 

 closing nights, when the demand is less, only the inferior 

 kind is used. 



