April 2, 1894.] THE TROPICAL AGRICULTURIST. 
659 
Albuminoid ammonia ... -002) -0024: 
Total solids 2-5200 2-2400 
Solids volatile on ignition -9100 -8400 
Fixed mineral matter ... 1-6100 1-3000 
Chlorine ... ... "0670 -0670 
Nitrites ... ... absent absent 
O.xygen absorbed ... . -0314 -0714 
When addetl to sterilised agar agar, No. 1 water 
produced uo iiiicro-oiganisms at the end of 4 days, 
No. 2 water produced several colonies. 
The following are analyses of Labugama water 
as it is delivered in Colombo, and the same after it 
had been passed through an animal charcoal filter, 
which had been live and a half months in use ; — 
Analysis of Colombo Water Supply. 
Unfiltered. 
Filtered. 
Grains^ gal. 
Grains %)■ gal. 
Free and saline ammonia... 
■0010 
•0008 
Albuminoid ammonia 
-0035 
•0014 
Total solids 
l-(ilO0 
1-8200 
Solids volatile on ignition... 
•8400 
•5600 
Fixed mineral matter 
-7700 
1 '2600 
Chlorine 
•1665 
•1800 
Iron 
0260 
•0120 
Nitrites ... 
absent 
absent 
Phosphates 
a 
b 
Oxygen absorbed from po- 
tassium perjnanganate, in 
presence of acid, in four 
hours, at the ordinary 
temperature 
0231 
•0170 
a Inappreciable, h Presence marked. 
From a chemical point of view the filtered water 
was the purer, but, from a biological point of view, 
the unfiltered water was much the purer. When 
tested with sterilised agar agar, the xinfiltered water 
was found to be practically sterile, while the filtered 
water had a high zymotic power.* W'ater which 
f)a.«sed through a filter which had only been three 
days in use was practically sterile, but when the fil- 
ter had been28daysin use, it has found to have con- 
ferred considerable zymotic power upon the water. 
The following is the average of the monthly 
analyses of Colombo Town water, during the 
year 1891, a year of exceptionally high rainfall, also 
the average for the previous sixteen months 
1831. 
Sept. 18S9 to 
Grains 
Dec. '890. 
per g-allon. 
Grains'}* gal. 
Free and saline ammonia... 
•0010 
•0009 
Albuminoid ammonia 
-0050 
•0055 
Total solids 
r8700 
2-0225 
Solids volatile on ignition... 
•9380 
■9836 
Fixed mineral matter 
•9320 
1 -0389 
Chlorine 
•1561 
•]6'27 
Iron. 
•0340 
•0551 
Nitrites... 
absent 
absent 
Oxj'gen absorbed in 4 hours 
•0263 
•0308 
The average colour of the water from August to 
December 1891, when a two feet stratum was view- 
ed through a Lovibond's tintometer, was matr bed 
by 2-2 degrees of yellow and '5 degrees of red. 
The zymotic pover of the water from July to 
December 1891 was very low, not averaging 
more than a half colony ])er culiic centimeter 
of water. It was observed that a low degree of 
colour was associated with a low zymotic power, 
the latter property increa-sing witli the eofonr. 
'•.By " zymotic power " ia RimT>ty fiieant ipower 
of developing mmrite organisms in sterilised 
culture medium without indicating that tlie 
oirganisina .so developed are either of a hurtful or 
harniless character. :.iu t 
The following table of analy.ses exhibits the con- 
stituents, the physical and microscopical charac- 
teristics of the water of the Labugama Keservoir 
at various depths, viz., 12, 24, 36, 48 and 59 feet 
from the surface, also some of the more important 
determinations in the examination of water from 
the Wakoya stream which flows into tlie re.ser- 
voir, and of water from a spring which flows 
into the scouring culvert of the reservoir : — 
2 . oo 
a 
73 S 5 
o » 
1 1° 
u5 
i . 
"Eg 
all 
^ ^ iO, :o CO cc ^ & 
2 . o o ;d a CO .c S 55 
C . - * . . . -. . . 
is t 
13 41 ,— i 
S =£ 2 »: ■ • ■ ™ ■ 2 • • 
" - = 5 — 
c ^ 2 o 
So ^(M-*iOO = 0 Tj-C 
- = - IC O; -* — "M — — 
3 £ 1? CI o o 
_e3 
^ CO 05 o c: o ir; 30 
— — — ^1 ; ] ~ 
c 
'5 
s 5 - c o X c -f 
v. — 
>5 
1 = ^ r. .5-- i ^ i 
fc, K is^ — C — «^ 
mi 
