564 Cut Pina 
and temporary existence. Generally a thick layer of dark brown scum 
prevails here and there over the surface, but the clearness of the water 
underneath is not affected. Pools I and II were dug in the latter part 
of the summer of 1917; unlike the water in the older pools, the water in 
these has continued perfectly clear all the time, so the presence or absence 
of color is due to the difference in age of these pools. Pools A to F, because 
_of their proximity to a much-used rail track, have been polluted to a certain 
extent by oily substances and animal feces. This is true also of some 
parts of the overflowed areas. Pools E and F were spoiled in the latter 
part of the season by being filled in with lumber fragments and a great 
quantity of waste salt. The general condition of the water in the differ- 
ent pools from August 17, 1917, to October 17, 1917, has been recorded 
as follows: 
Pool August August August |September |September| October October 
17 19 22 7 18 3 17 
Greenish Pale Greasy Greasy Greasy Greasy Greasy 
A brown greenish films films films, films, flms, 
eTayish grayish grayish 
B Green, Pale Somewhat Clear, Greasy Greasy Greasy 
brown- greenish clear, slightly films, films, films, 
ish at thin pale greenish greenish grayish 
surface greasy greenish brown 
films 
C Brownish, Pale Thin Thick Pale Pale Greasy 
slightly | greenish greasy greasy greenish | greenish films, 
dark films film, brown brown grayish 
brown- 
ish 
D Brownish, | Brownish Thin Deep Greenish | Greenish | Brownish 
slightly greasy green brown brown 
dark films 
E Somewhat | Brownish | Spoiled 
clear 
F Brownish | Spoiled 
oY } Clear throughout the season 
