56 CARNEGIE INSTITUTION 



A sub-basement, in which air circulates at a fairly uniform tem- 

 perature, is also essential to dryness and constant temperature in 

 the main basement where the larger permanent apparatus, for which 

 stability is essential, is mounted. Within this sub-basement, in- 

 closed by properly insulating walls, one or two underground cham- 

 bers would be provided for such secular experiments as require 

 constant conditions for longer petiods of time, like diffusion ex- 

 periments in viscous media. Such rooms require to be visited by 

 the observ^er only at long intervals. 



Vertical shafts for experimental purposes and special ventilation 

 could be provided by towers at the corners of the building. Ordi- 

 nary ventilation, hood flues, etc., would be carried by the outside 

 walls, so far as practicable. 



14.. Floor space required. — A building of this character, to meet 

 the needs of the work contemplated, would contain three (3) work- 

 ing floors above the subbasement. The first, or main basement, 

 would contain the stone piers and would mount all apparatus 

 requiring great stability. The next, or main floor, would con- 

 tain the librar>^ director's room, and general laboratory rooms ; 

 the upper floor the chemical laboratary, photographic laboratory, 

 and work rooms for such apparatus as does not require extreme 

 stability. At least a part of the roof should be available for 

 mounting special apparatus out of doors. 



This building would cover some 12,000 feet of ground over all, 

 which, taking the distribution of space followed in the Reichsan- 

 stalt, would give a net floor space, exclusive of halls and corridors, 

 of some 16,000 feet, of which perhaps 4,000 would be taken up 

 with librarj'-, store rooms, balance room, clock room, mercury 

 room, toilet rooms, offices, etc., which would be used by the entire 

 staff" in common, leaving 12,000 feet to be placed at the disposal of 

 the director and the five investigators, and for reserve space in an- 

 ticipation of future need. Approximately 1,500 feet would there- 

 fore be available for each investigator, with his assistant and 

 mechanical helpers, for all the problems upon which he might be 

 engaged, with 3,000 feet in reserve. 



Z5. Special coiistructio7i of building. — One other feature of the 

 Reichsanstalt has proved of especial value, viz : The arched con- 

 struction, which is maintained throughout the building, and enables 

 the partitions between adjoining laboratory rooms to be taken 

 away and two or more rooms thrown into one to meet the require- 

 ments of a particular experiment. Each arch section, or smallest 



