86 REPORTS OF INVESTIGATIONS AND PROJECTS. 



all building materials and labor troubles in several of the building trades. 

 The successful result is therefore an exceptional credit to them. 



When ready, the plans were privately offered to eight building contractors 

 for bids. The only bid which came within the appropriation was made by 

 the firm of Richardson & Burgess, of Washington, to whom the contract was 

 let, without essential modification, in June, 1906. Excavation was begun at 

 once and construction continued without serious interruption throughout the 

 winter, and the building was so far completed that we were allowed to move 

 into it during the last few days of June, 1907. This enabled us to meet the 

 desire of the Director of the Geological Survey that the space in the Survey 

 building, which had been occupied temporarily by the Laboratory, should 

 become free before July i of the current year. 



The completed building is a substantial structure of attractive appearance, 

 the architectural features of which are in the Spanish style, with wide over- 

 hanging roof. 



The character of the building and the floor-plan may be seen from plates 

 6 and 7. Its distinctive features require some further description. It com- 

 prises three floors and an unfinished attic, each floor containing about 6,400 

 square feet. The available floor-space is therefore about four times greater 

 than the floor-space occupied in the Geological Survey, and affords not only 

 necessary relief from the serious overcrowding which had been necessary 

 there, but some desirable provision for the future of the undertaking. The 

 rooms are grouped about a long central hallway on each floor, the hallway 

 being left wide enough to accommodate instrument cases on both sides. The 

 floors are of Portland cement throughout, covered in the working-rooms with 

 German linoleum. The building is fireproof, except for the roof, even the 

 tables and chemical hoods being almost entirely of stone, iron, or glass. In- 

 direct steam heating with forced circulation of air is employed, the exhaust 

 steam from the power plant being utilized to heat the entire building. 



Special Features. — In preparing the plans of the laboratory, two problems 

 of construction arose, each of which appeared to require special treatment 

 at a minimum of expense. These were: (i) Such thermal insulation as 

 would enable investigators to work without undue discomfort throughout 

 a Washington summer, and (2) to provide against the disturbance resulting 

 from the heavy machinery belonging to the plant itself without erecting a 

 separate building for it. 



There are three common methods of meeting the first situation : 



(i) By reducing the heat conductivity of the outside walls by building 

 them double, with an air space between. 



(2) By lining the walls with light non-conducting material, like magnesia 

 brick. 



