4 , BULLETIN 951, U. S. DEPARTMENT OF AGRICULTUEE. 
proportion of one part Portland cement to two 
sand, and it was rough scratched. After this 
parts of clean, sharp 
coat had thoroughly 
dried, the second 
coat, approxi- 
mately one-fourth 
inch in thickness 
and mixed in the 
proportion of one 
part of Portland 
cement to one and 
one-half parts of 
clean, sharp sand, 
was applied a-nd 
brought to a float 
finish. 
Shelves. — Shelves 
were originally con- 
structed (fig. 2) of 
1-inch galvanized- 
metal pipe, covered 
with galvanized- 
wire mesh made of 
Xo. 16 wire with 
four meshes to the 
inch. The wire 
mesh was securely 
soldered to the pipe 
frame, care being 
taken to leave no 
projections that 
might cut or scratch 
those w orldng in 
t h e compartment. 
It was found, how- 
ever, that the wire- 
mesh covering of- 
fered more or less 
resistance to plac- 
ing the trays on 
the shelves, and it 
was subsequently 
removed and the 
trays containing 
the flasks are now 
placed directly on 
the pipes. All the 
trays containing the 
