THE BOILER-ROOM OF MACHINERY HALL.—Never before was such a boiler-room as that which delighted engineers in Machinery Hall. It must needs be enormous, for it supplied the force for all the lights and machinery of the great buildings, but those who had never seen it were none the less astonished when they entered the great room. It extended north and south in the annex, and to look down it was like looking down a street the end of which [...]