230 



SCIENCE. 



[Vol. V., No. 111. 



trees or buildings near the laboratory to inter- 

 fere with the employment of sunlight for optical 

 purposes from dawn to twilight. The west- 

 ern wing contains no iron, all the gas-pipes 

 and steam-pipes being made of brass. This 

 wing has a separate entrance, and can be iso- 





BASEMENT. 



A, workshop; B, forge; C, battery-room ; D, fire-room; E, coal ; 

 F, mercury-room; G-, receiving-rooms; II, special investiga- 

 tion rooms; I, constant-temperature room; J, engine-room. 



lated from the eastern wing, which contains the 

 large lecture-room and the elementary labora- 

 toiy. The vibrations resulting from the move- 

 ment of classes are thus obviated in the west- 

 ern portion. Each room in the basement and 

 first floor of the western end is provided with 

 brick piers, which are so arranged that instru- 

 ments placed upon the south-west or the north- 

 west corner piers can command long lines of 

 sight east and west, and north and south. In 

 the centre of the western wing, below the floor 

 of the basement, is a constant-temperature 

 room. This room is at the base of a tower, 

 the walls of which are at least a foot from the 

 main walls of the building. This tower rises 

 to the roof, from which, however, it is entirely 

 separate. In this way the effect of the wind is 

 prevented from communicating vibrations to 

 this inner tower. In the tower are placed 

 large shelves of slate, which serve as piers 



FIRST FLOOR. 



A, space under lecture-room; B, first-story cabinets; C, prepa- 

 ration-room ; D, recitation-room ; E, professor's room; F, bal- 

 ance-room; Gr, special investigation rooms; H, elevators. 



on the second and third floors. The arrange- 

 ment of rooms in the western wing is such 

 that any room can be entered from the main 

 hall without going through any other room. 

 Moreover, two or more rooms can be thrown 

 together if any experiment demands such an 

 arrangement There is gas and water in each 

 room. Provision is also made for a line of 



sight entirely within the building nearly two 

 hundred feet long. 



The portion between the two wings is de- 

 voted to recitation-rooms and cabinets. A 

 lecture-room capable of seating an audience 

 of three hundred is placed on the first floor of 





SECOND FLOOR. 



A, lecture-room ; B, second-story cabinets; C, professor's room ; 

 D, elevator ; E, professor's room ; F, library ; Gr, optical rooms ; 

 H, Rum ford lecture-room; I, sound; J, special investigation 

 room; K, chemical laboratory; R, recitation-room. 



the eastern wing. Immediately over it is the 

 large elementary laboratory sixt} r by sixt}^ feet. 

 Connected with the latter are several rooms for 

 special investigations, which do not require the 

 great steadiness of the western end. Immedi- 

 ate ry beneath the lecture-room is the workshop, 

 together with a battery and a mercury-room. 

 Power is conve}'ed to the workshop through a 

 large tunnel which connects with an outside 

 engine-house, in which is placed a twenty-five 

 horse power engine and a seven horse power 

 gas-engine, together with two d3'iiamo-electric 

 engines. 



The ground upon which the laboratory is 

 placed consists of gravel, with a substratum of 

 clay, which, however, is below the lowest foun- 

 dation of the laboratory . The nearest street 

 is more than three hundred feet distant, and it 

 is found that no prejudicial vibrations are com- 



THIRD FLOOR. 



elementary laboratory; B, special investigation rooms; 

 C, library; D, elevators; E, photographic chamber. 



municated to the piers. A vessel of mercury 

 placed upon them, however, shows slight cris- 

 pations and vibrations. The shelves placed in 

 the isolated tower are steadier than the piers. 

 This is probably due to the effect of the out- 

 side walls of the building in cutting off the 

 surface vibrations, and suggests, that, if the 

 future builders of physical laboratories desire 

 ideal steadiness, the}^ should sink walls outside 



