466 Scientific Proceedings, Royal Dublin Society. 
(Titrations by bichromate 1 cc. = 1 cc. oxygen at N. T. P.) 
Blank experiment required, ; : J BP Dil GG, 
Oxygen determination required, . ; SPOT ae 
0-14 ,, 
Gasometric Analysis. 
200 c.c. of effluent gave— Equivalent to, per litre— 
COs 2 24°42 ce : : i LZPPU0): Cs. 
ON: OA 4, : : : ; 0°35 ,, 
ING Verh ee GelON ware chan hn annae 15°50 ,, 
otal eOT5ON a ae oom 
Dissolved oxygen, per litre, by new process (permanganate), 0°66 C.c. 
” » 39 »  (bichromate), . 0°42 | 
ae A », by gasometric analysis, . 7) Ozoomer 
Sewage (Belfast) from tank previous to filtration through eaperi-— 
mental “ Bacteria Beds.’ —(Titrations by permanganate | c.c. = 1 cc. 
oxygen at N. T. P.) 
Blank experiment required, : : 5 DY Cxe. 
Oxygen determination required, . : 5 G85. 
ONS .. 
Titrations by bichromate, 1 cc. = 1 cc. oxygen at N. T. P.) 
Blank experiment required, F ; Wa AeDonenes 
Oxygen determination required, . : . $402 one 
0-00. ,, 
Gasometric Analysis. 
200 c.c. of the sewage gave— Equivalent to, per litre— 
COs 82. 3211.8) ChCs ee : ; ( 118:92 c.c. 
Oz 5 MOMS, ¢ ; j : : none. 
ING ate UAE) a : L ; j 14°76 ,, 
Motaly- | 26-73 ,. ve eee eS S GS mee 
The following experiments were made in order to ascertain 
whether the presence of nitrates or nitrites would interfere with 
the accuracy of the process :— 
Effect of Nitrates.—A quantity of tap water was thoroughly 
aerated, and after remaining at rest for a quarter of an hour was 
