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POPULAR SCIENCE MONTHLY. 



received, it- isolation and elevation make it comparatively free from 

 noise and dust, while the building is well lighted by large windows, 

 heated by hot water and provided with gas, electricity and telephone. 

 The upper portion of the building contains three rooms, known as the 

 general laboratory or [(reparation room, the biological laboratory and 

 the chemical laboratory. In the basement are the physical laboratory, 

 the furnace room and the general storeroom. The general laboratory is 

 used for the shipment of samples, the washing of glassware, the sterili- 

 zation of apparatus, the preparation of culture media and for such chem- 

 ical processes as might charge the air with ammonia and the fumes of 

 acids. The biological laboratory is devoted to the bacteriological and 



Fig. 



Laboratory of the Sewer Department, Worckster, Mass. 



microscopical examination of samples of water and to the study of the 

 various organisms found. It also serves as the office of the director. The 

 chemical laboratory is the largest of the three rooms. Its atmosphere is 

 kept free from ammonia and acid fumes in order not to vitiate the 

 results of the water analyses there carried on. Analyses of coal are also 

 made in this room. A storage room opens from the chemical laboratory 

 and there is also a small dark room. All three laboratories have marble 

 tiled floors, and the tables and shelves are covered with white tiles 

 throughout. The partitions between the rooms are largely of glass. 

 The apparatus is of the most complete description, much of it having 

 been designed for the particular work at hand. The physical laboratory 



