82 UNITED STATES NATIONAL MUSEUM 



is dumped from wagons on a grate in the driveway at the side of 

 the bunker, it passes by gravity down a chute and into a series of 

 buckets attached to an endless chain,, by which it is conveyed to a 

 point near the ceiling and delivered to a spiral running in a trough 

 suspended from the ceiling. This spiral is pivoted at one end and 

 connected to the driving shaft through spur gears so that its outer 

 end, moving in a circular track, can distribute the coal to any point 

 in the room. The coal for the reserve bunker must first be taken into 

 the northern one, from which, after being lifted to the higher level, 

 it is carried over the driveway by means of a second spiral, but as 

 this is in a fixed position, in order to completely fill the bunker, the 

 coal has to be partly distributed by hand. 



For conveying coal to the boilers, two steel cars, of one ton capacity 

 each, are employed. They run on an industrial railway track lead- 

 ing from each bunker across the corridor into the boiler room, and 

 thence along the fronts of the boilers. The coal is passed from the 

 cars to the hoppers of the stokers by hand. 



The ashes from the furnaces are dumped into pits, one under each 

 boiler, whence thej are drawn into a car having a capacity of one 

 cubic yard and running on a track in a main pit extending along the 

 entire front of the boilers. From a branch opening in the adjoining 

 corridor the car is lifted by an electric hoist and moved along a 

 suspended trolley to the east driveway where the ashes are emptied 

 into carts. 



Seating system. — The heating system of the new building is of the 

 hot water type direct radiation. The water is brought to the neces- 

 sary temperature by means of heaters of the Alberger Condenser 

 Company's make, two of which are provided. These machines consist 

 of cast-iron bodies with corrugated copper tubes made into cast-iron 

 heads, and are so designed that the water entering the bottom passes 

 three times through the tubes before leaving the heaters at the top. 

 Exhaust steam from the engines and pumps circulates around the 

 tubes. When the exhaust is not sufficient in quantity live steam is 

 added to make up for the deficiency, being introduced through either 

 a 4-inch connection to the live steam main or a 6-inch connection to 

 the exhaust main, which contains a Bridgman Brothers automatic 

 reducing valve. To care for the expansion of water in the system a 

 tank is located in one of the flues in the rotunda walls at a height 

 of about 20 feet above the third floor. An automatic ball cock con- 

 nected to the city water supply keeps the water in the tank at a con- 

 stant height, while an overflow to the sewer carries off any surplus 

 as expansion takes place due to increase in temperature. Circulation 

 through the system is forced, the power being supplied by two volute 

 Alberger pumps, direct connected to Westinghouse motors of 20 horse 

 power capacity. The two heaters and pumps are duplicates, one of 

 each being held in reserve while the other is in use. 



