NATURAL HISTORY BUILDING 67 



against the wall surface of the second story at the eastern end of the 

 central skylighted hall in the east wing. It is entitled "Diana of 

 the Tides," and represents the goddess standing erect in her chariot, 

 a rainbow-tinted sea-shell drawn by four horses which typify the 

 flow of the tides, their action repeating and amplifying the rhythm 

 of the breaking waves. The moon behind the goddess in the east rises 

 through the purple shadows that follow the setting of the sun in the 

 west. The work was executed by Mr. John Elliott and is a gift to the 

 Museum from Mr. and Mrs. Larz Anderson. 



FINISHED FLOORS 



Four different kinds of material have been employed for the fin- 

 ished floors, namely, a terrazzo pavement throughout the first and 

 second stories and in the north central hall in the ground story, all of 

 which are intended for exhibition purposes, and also in the audi- 

 torium; marble in the south pavilion, the north entrance vestibule 

 and lobby and the toilet rooms ; wood in nearly all parts of the build- 

 ing which are constantly occupied by employees, including the entire 

 third floor with the exception of a few rooms, both ranges and most 

 of the side rooms of the wings in the ground story, and a few isolated 

 rooms elsewhere; and cement in the wing spaces of the lofts, in the 

 ground story east and west wings outside of the side rooms containing 

 wood floors, in the corridor in front of the east freight elevator in the 

 lower story, and in certain small rooms and closets in the first, second 

 and third stories. The marble floors are described in connection with 

 the several sections and compartments of the building in which they 

 occur. The character and construction of the other floors are as 

 follows : 



Terrazzo floors. — The terrazzo pavement is of a high grade, con- 

 taining a relatively large percentage of marble, the pieces of which 

 range in size somewhat above the average customarily employed in 

 this work. Two kinds of marble have been used, Sienna and Verona, 

 the former varying in color from cream to a deep yellow, the lat- 

 ter being yellow and very dark red. The matrix consists of 

 \\ inches of Portland cement mortar, laid upon a base of 

 Portland cement concrete which in turn rests upon the floor 

 construction. These floors have been laid in rectangular blocks 

 forming regular courses extending both lengthwise of and across 

 the halls, but there is some variation in the dimensions of blocks 

 and consequently in the widths of courses, which measure gen- 

 erally from 4 feet 7 inches to 5 feet 3 inches, in order to carry the 

 pier base lines, etc. By first constructing alternate blocks in diagonal 

 lines and allowing these to harden before the others were added, dis- 

 tinct joints have been formed between the blocks, designed to direct 



