REPORT OF NATIONAL. MUSEUM, 1924 21 



ticularly was this true in the Arts and Industries Building. It is 

 intended to make further changes in the Smithsonian Building be- 

 fore the beginning of another heating season. In order to properly 

 heat the third floor of the Natural History Building it will be neces- 

 sary eventually to remove all the radiators placed against partition 

 walls and replace them with radiators under the windows. 



Other repairs to the power plant included the purchase of two 

 Copes boiler feed-water regulators for two of the boilers, replacing 

 unsatisfactory regulators which had been in service for 15 years. 

 These four boilers are in excellent condition. The length of time 

 they have been in service, however, makes it essential to provide for 

 replacing all the tubes at any early date — too large an item to be 

 cared for in one year from the general appropriation. Sufficient 

 tubes and tile baffle plates are in stock to entirely retube two of the 

 boilers and the work will be started before the beginning of another 

 heating season. 



The electric generating equipment for the first time since the in- 

 stallation of the power plant has carried a load approximating its 

 maximum capacity. At times on dark days there was a steady maxi- 

 mum load of 1,650 amperes. The marked increase in load is due 

 primarily to the addition of the Freer Building, and, secondarily, to 

 the natural increase in the demand for current in all the Museum 

 buildings. The increase in load has resulted in the more efficient 

 operation, so that this year the cost of current generated, $0.02271 

 to the kilowatt hour, is less than in the last few years. The lower cost 

 of coal was also a factor. 



Changes in the electric cables leading from the Potomac Electric 

 Power Co. lines in B Street north to the switchboard in the Natural 

 History Building were rendered necessary by the increased demands. 

 The main feeder, consisting of two 700,000 centimeter cables and 

 one 250,000 centimeter cable, was increased by two cables of 750,000 

 centimeters each on the positive and negative sides, and the old 1,000 

 ampere switch was replaced by a 1,500 ampere double pole General 

 Electric circuit breaker of a maximum capacity of 3,000 amperes. 

 Other cables, when required, can be added to the two sides of the 

 feeder line without the necessity of changing the circuit breaker. 

 The service from the commercial power plant has been much more 

 satisfactory since these changes were made. 



The ice plant, in operation 4,800 hours, produced 301.1 tons of ice 

 at a cost of $3,003 a ton, exclusive of labor. The decrease in cost 

 this year resulted from lower cost of electric current and the more 

 efficient operation of the compressor. The capacity of the plant was 

 too small to supply the demands of all the buildings of the Smith- 

 sonian group during the summer of 1923. Sufficient ice has b»en 

 manufactured since then to meet the requirements, with the excep- 



