10 NATURE 
[Marcu 4, 1915 

screens from the surrounding aisles. Our second 
figure shows part of an L-shaped range on this 
floor, with the outer windows on the right, and 
on the left windows to the open court. The actual 
interior width is 54 ft. 2 in., and the ceiling height 
is 20 ft. The severity of the interior is not un- 
pleasing, and for exhibition galleries is better than 
any Ornament. 
The general absence of interior structural walls 
has necessitated the introduction of piers and 
columns arranged in one or more rows, as shown 
on the right of our Fig. 2. These, as well as 
the wall piers, are at a distance of 18 ft. 6 in. from 
centre to centre. Rooms can be formed in 

Fic. 2,—United States National Museum, Natural History Building. 
multiples of this unit by the building of partitions 
between the columns, or to meet varying needs the 
exhibition galleries can likewise be broken up by 
slighter screens of material appropriate to each 
case. As the museum grows and changes there 
will be no difficulty in making such alterations, for 
all the mains from the heating and lighting plant 
run in tunnels under the basement, and are con- 
nected with each floor by two vertical chases cut 
in each wall pier. These chases also serve for 
electrical communications, ventilating flues, 
vacuum-cleaning pipes, hot and cold water supply, 
and the like. Thus for the future we can almost 
imagine that in this building “neither hammer, 
nor axe, nor any tool of iron” will be heard in the 
NO. 2366, VOL. 95] 
hands of the workmen, but that the staff will be 
left to work in peace. 
The vacuum-cleaning pipes lead from a single 
pump in the basement, driven by a 25-h.p. motor, 
and are connected with seventy-three inlets to 
which can be attached rubber dust-hose provided 
with a complete equipment of dusting tools. These 
will be of particular value in the cleaning of 
exhibition cases. 
The rounds of the night-watch are controlled 
by a system of recording clocks with paper dials, 
which mark the signals and transmit them to a 
central station. Time is indicated by sixteen 
dials electrically controlled by a master clock 

The Gallery of Ethnolozy, on the first storey of the East range. 
and corrected each from the Naval 
Observatory. 
There are six electric Otis elevators, four for 
passengers and two for freight. The latter are 
near the large wagon entrances, and run from 
ground to attic; their cars measure Vp Bilis} took, 185% 
11 ft. 4 in., by 12 ft. high, and can take a load 
of 12,000 lb. 
Nearly all the ground storey of the east wing is 
occupied by the machinery plant, which serves the 
older buildings also. Except for the’ generator 
engines, the two stoker engines, and six pumps in 
the engine-room, which are worked by steam, all 
motive power is supplied by electricity and is con- 
veyed to the various laboratories and workshops. 
noon 
