224 
THE TROPICAL AGRICULTURIST. 
[Oct. i, 1894. 
During the period reported upon previous to 
September 1889, my object was partly to discover 
the cause of the Water Supply, at times, anil in 
certain parts of the town, becoming discolored ; 
and to this end some of the samples analysed were 
drawn from standpipes, the water from which had 
been reported to me as of inferior quality. During 
the present period reported upon I have aimed 
lnore at determining the average quality of the 
Water Supply, and, in my later analyses, to 
secure this object more effectually, the sample- 
since July have been drawn from several stand- 
pipes. It is well to bear this consideration in 
mind when instituting a comparison between the 
qualities of the water during two periods referred 
to. 1 submit herewith a tabular view of these 
monthy analyses since September 1889, also the 
average results for both periods. 
The analyses shew an appreciable increase in 
the average amount of free and saline ammonia 1 
but more than a compensating decrease in the 
amount of albumenoid matter, as represented by 
the albumenoid ammonia. For an unliltered 
upland surface water these results are very satis- 
factory, but the amount of albumenoid ammonia 
continues to be above the average of the 46 
English Water Supplies, and of the 8 London 
Water Supplies quoted in my letter of 28th April 
last thus ; — 
Albumenoid 
ammonia. 
Grs. per gal, 
46 English Water Supplies ... -0042 
8 London Water Supplies ... '0039 
Colombo water June 1887 to Aug. 1889 -0083 
do Sept. 1889 to Dec. 1890 -0u53 
Many of the English, including the London 
Water Supplies, are filtered waters ; but, as they 
are filtered before being supplied to the consumer, 
the above comparison is a legitimate one. 
I have to record a noteworthy change in the 
living organisms predominating in the water from 
the standpipes. During the greater part of the 
first period reported upon the most conspicuous 
organism was cyclops quadricornis, of which 20 
per gallon were frequently counted, and as many 
as 100 per gallon have been observed. During the 
present period, from September 1889 and for some 
time previously, this organism has not been met 
with in any of the samples drawn for analysis. 
It would be interesting to know to what cause 
the absence of this organism is to be attributed, 
whether from the multiplication of fish in the 
reservoir which prey upon it, or to the water 
being drawn off from a level not frequented by it. 
Some authorities say that it is always found 
within tv\ o feet of the surface, but in a bottle of 
water filled at 12 feet below the surface of the 
reservoir I found it, while from bottles filled at 
depths of 24, 36, 48 and 59 feet it was absent- 
Other members of the entomostraea have been 
1 found in most of the samples drawn, but thc*e 
I were absent from the samples drawn in November 
and December, last. 
(Jus. 
I have a very favorable report to make npon the 
quality and purity of the Colombo ga* during the 
past year. The Gas Company is bound to supply 
gas of a 11 illuminating power equal to that of 12 
standard candles, and which does not contain 
more than 20 grains of sulphur per hundred 
cubic feet. The gas supplied during the past year 
has been of an a\ erage illuminating power ojual 
to 161 standard candles, the minimum having 
been 153, and the maximum 17 2 xtandard 
caudles. 
The gas, too, has been remarkably free from 
sulphur, the maximum amount having been 8 6, 
the minimum 16, and the mean 3 6 grain* per 
hundred cubic feet. This excellent result lias 
been partly due to more efficient purification, but 
also to the small proportion of sulphur in the 
coal used, which has been Australian coal. 
If we draw out the average results obtained for 
the past eleven years in tabular form the com- 
parison will be found greatly in favour of the year 
just closed. 
Illuminating 
power in Sulphur in grains 
Year. standard per hundred 
candles. cubic feet. 
1880 14 4 10(?) 
1881 14-4 11-9 
1882 13*5 157 
1883 13-5 18-8 
1884 14 17-7 
1885 138 15-6 
1886 13-8 19-7 
1887 13 9 18 
1888 13 14-2 
1889 15 1 9 3 
1890 16T 3-6 
The past year is the first for which a minimum 
average pressure during the time-table-hours of 
lighting has been contracted for. The gas, ac- 
cording to contract, should be supplied at a 
pressure equal to that of a column of water nine- 
tenths of an inch in height. The actual average 
registered pressure has been equal to that of a 
column of water of 9 - 59 tenths of an inch in height. 
M iscellaneous Substances. 
The following is a list of the miscellaneous 
substances I have been called upon to examine 
and report upon since the beginning of May. 
Proposed Water Supply for Negombo, other well 
Avaters, drainage water, various minerals, coconut 
poonac, castor cake, nitre, cow's milk, condensed 
milk, mineral oil, roasted coffee, sulphate of 
quinine from the Indian Government cinchona 
plantations, piece goods (to determine whether 
sea or fresh water damaged), prepared copperah, 
annatto, coconut-milk, boiler scale, sugar (to 
determine for the Customs whether refined or 
unrefined), crushed tallow oil cake. 
The extensive adulteration of milk with water 
practised in Colombo has not come before me 
officially. Samples of ordinary milk have been 
received only from parents anxious to know if the 
cows kept for the use of their young children were 
yielding wholesome milk. The adulteration of 
milk with water which is so jealously watched in 
all large towns in England is not likely to be put 
