Next in authority is the fire boss. It is his duty to examine, every morning before the men come to their work, every place in the mine where explosive gas is evolved or likely to be evolved, and to give the necessary instructions to the workmen regarding the same. He also has general oversight of the ventilating system, and sees that all stoppings, doors, brattices, and airways are kept in proper condition. The driver boss has charge of the driver boys and door boys, and sees that the mules are properly cared for and are not abused. Each driver boy has charge of a mule, and the mule draws the empty cars in along the gangway and up to the faces of the chambers, and draws the loaded cars out to the foot of the shaft. The door boy must stay at his post all day and open and close the door for the cars to pass in and out. The use and necessity of these doors will be explained in a subsequent chapter. Then there are the footmen, carpenters, blacksmiths, masons, and tracklayers, whose occupations in the mines are apparent from the names which indicate their several callings. Finally we have the miners and the miners’ laborers, and it now becomes a matter of especial interest to inquire into the character of their work and their manner of performing it. To drive a gangway or airway is much the same as driving a chamber, except that the gangway is only about one third the width of a chamber, and must be driven on a slightly ascending grade. Gangway driving is special work, for which the miner receives special wages, it being impossible in this work to send out as much coal with the same amount of labor as can be sent out in chamber work. And since the great bulk of coal is taken from the chambers, it will be better to observe in one of them the processes of mining. There are usually four workmen, two miners and two laborers, employed in each chamber. The miners are employed by, or are under contract with, the coal company, and the laborers are employed by the miners, subject to the approval of the mining superintendent. The two miners divide their profits or wages equally with each other, and are called “butties.” A miner’s butty is the man who works the chamber with him on halves. A laborer’s butty is the man who is associated with him in the employ of the same miners. Between the miner and the laborer there is a well-defined and strictly observed line of social demarcation. The miner belongs to the aristocracy of underground workers; the laborer is of a lower order, whose great ambition it is to be elevated, at an early day, to that height on which his employer stands.