Chemical Changes in Mixtures of Sewage and Sea-Water. 335 
These were then completely immersed in water contained in a 
zine bath, the temperature of which was regulated by a sensitive 
thermostat and an automatic (water-driven) stirrer. 
In analysing the dissolved gases, a given quantity (200 c.c.) 
of the mixture was withdrawn from one of the bottles through a 
tube plunged to the bottom, and rapidly transferred to the boiling- 
out apparatus. In this way, only the lower layers of liquid were 
removed for analysis, and contact of the sample with air avoided. 
As in Adeney’s experiments, a small quantity of sulphuric acid was 
added before boiling out the gases, to decompose any bicarbonates 
present. 
In the aerobic experiments, a large confectioner’s jar was used 
to contain the mixture, and this was heated in a water-bath. 
Inside the jar a thermostat was placed, as well as a stirrer, 
both being made of glass. For obvious reasons no analyses of 
dissolved gases were made in this series of experiments. 
The sea-water used in all the experiments was collected from 
a spot (near Black Head) just outside Belfast Lough, and at a 
time of the tide when there was a strong current from the Irish 
Channel, so that the water was uncontaminated. ‘Three samples 
of sea-water (collected on different occasions) were employed, which 
we shall call 1, 2, and 38. The following determinations were 
made in them :— 
Sra- WATER. 
(In cubic centimetres per litre (In parts per 100,000.) 
Tempera- BNe INo IL, 125)) 
E of when Dissolved Gases. | Unoxidized Nitrogen as || Oxidized | ‘Oxygen 
Sample.| collected | Nitrogen | absorbed ”’ 
a (Ce easel Ne mas in 4 hours 
COx. || Oazo Nz. | Total. NH aa Total. Nitrates. | at 80° BF. 
| | 
1 8°8 45-20 | 6:95 | 12°16 | 64-31 || -0013 | -0058 | -0071 Pees 0°1328 
| 
2 8)°9) — — = — || -0018 | -0066 | -0079 | 0033 0°0952 
| | 
3 11:0 — —- = — | — — = | = a 
| 
\ 
The sewage was obtained from the Belfast Main Drainage 
system, close to the Outfall Works, either from the sewer itself or 
SCIEN. PROC., R.D.S., VOL. IX., PART. III. 2B 
