ApENEY—The Reservoir at Roundwood. 209 
In the following table are given two series of analyses of each 
sample; one series of each sample being made on the Monday 
(November 138th), following the Saturday on which they were 
collected, and the other series on the second Monday (November 
20th) following. The samples employed for the two second 
series of analyses were kept, during the week’s interval, out of 
contact with the air in glass-stoppered bottles. I ought also to 
state that the original samples, from the time they were collected 
at the Waterworks until the commencement of the analyses, were 
kept in bottles completely filled and carefully stoppered with glass 
stoppers. 
TABLE GIVING THE RESULTS OF ANALYSES. 
[Results expressed in parts per 100,060. ] 
In FREsH SAMPLES. 
CONSTITUENTS. | Unfiltered. Filtered. | Differences. 
Nitrogen as albuminoid ammonia, . 0-009 0-005 — 
Nitrogen asammonia, . ... . 0-032 0-001 + 0:031 
Nitrogen as nitrates, ..... 0:033 0-069 — 0°036 
Nitrogen as nitrites,. . . ‘ 0-000 0-000 — 
Total combined inorganic nitrogen, . 0-065 0-070 — 0:005 
Chlorine nec ass aback edie ae hae 1-100 1-100 — 
Dissolved gases :— 
Carbon dioxide, . .:. . 1-250 1-386 — 0°136 
Oxyeens i Ga es Sy 17143 0-935 + 0°208 
Nitrogen)! sr Sula, sete 2°092 2°124 — 
» 
In SAMPLES KEPT OUT OF CONTACT WITH AIR FOR SEVEN DAYS. 
CONSTITUENTS. | Unfiltered. | Filtered. | Differences. 
Nitrogen as albuminoid ammonia, . — — — 
Nitrogen agammonia, . ... . 0-030 0-901 + 0:029 
Nitrogen as nitrates, . ... . 0°035 0-069 — 0°034 
Nitrogen as nitrites, . . 3 0-000 0-000 — 
Total combined inorganic nitrogen, 4 0:065 0-070 — 0-005 
Cinligrin®, 6.0, a. oc SSay oneoe oo — — — 
Dissolved gases :— 
Carbon dioxide, . .. . 1:257 1-403 — 0-146 
OxageemAnitks yeni sa) Moll -t) 12 1-146 0-931 + 0°215 
INGtrOmeM Rp Ese yite ls 2°085 225i) 5 — 
