Parts in 100,000 New York. Brooklyn. Jersey City. Philadelphia. Boston. Washington. Rochester. Cincinnati.
Free ammonia. 0·0027 0·00075 0·00475 0·001 0·01325 0·006 0·0114 0·0115
Albuminoid ammonia. 0·027 0·00825 0·0427 0·018 0·0605 0·027 0·023 0·024
Oxygen required. 0·81 0·413 0·95 0·46 1·77 0·600 0·790 0·860
Nitrites. None None None None None None None None
Nitrates. 0·8325 1·2025 0·9065 0·6845 1·2395 0·8325 0·629 0·740
Chlorine. 0·350 0·550 0·235 0·3000 0·315 0·270 0·195 0·805
Total hardness. 3·300 2·270 3·200 4·400 2·100 4·800 5·500 6·400
Total solids. 11·800 6·000 9·300 14·300 8·500 11·500 10·000 16·200
Mineral matter. 5·000 5·000 3·400 6·000 2·000 5·500 4·000 9·000
Organic and volatile matter. 6·800 1·000 5·900 8·300 6·500 6·000 6·000 7·200

Parts per 100,000. April. May. June. July. August. September. October. Nov. Dec.
3rd. 6th. 26th. 13th. 30th. 15th. 30th. 19th. 31st. 15th. 29th. 14th. 30th. 15th. 1st.
Appearance, &c. Cl. Sl. Tb. Tb. Cl. Cl. Cl. Cl. Cl. Cl. Cl. Cl. Cl. Cl. Cl. Cl.
Odour (heated
to 100° Fahr.).		 None None None None None None None None None None None None None None None
Chlorine in
chlorides		 0·278 0·348 0·244 0·348 0·226 0·279 0·226 0·278 0·313 0·209 0·208 0·272 0·243 0·312 0·295
Equivalent to
sodium chloride.		 0·459 0·575 0·400 0·574 0·374 0·459 0·374 0·459 0·517 0·344 0·343 0·458 0·400 0·515 0·486
Phosphates None None None None None None None None None None None None None None None
Nitrites None None None None None None None None None None None None None None None
Nitrogen in
nitrates and
nitrites.		 0·0403 0·0494 0·034 0·0469 0·0371 0·0395 0·0387 0·0469 0·0486 0·037 0·0477 0·041 0·047 0·048 ..
Free ammonia 0·001 0 0·002 0·003 0·0005 0·002 0·003 0·003 0·001 0·004 0·002 0 0·003 0·001 0·0032
Albuminoid ammonia 0·009 0·0166 0·0086 0·007 0·014 0·008 0·011 0·014 0·009 0·016 0·0094 0·013 0·015 0·014 ..
“Hardness”
equivalent to
carbonate of lime—
Before boiling 4·73 4·082 4·280 3·860 4·968 4·268 4·332 4·586 4·332 5·096 3·949 4·520 4·512 3·840 3·729
After boiling 4·31 3·787 3·510 3·500 4·586 4·268 4·332 3·949 4·332 4·459 3·822 4·294 4·512 3·390 3·164
Organic and
volatile (loss
on ignition).		 6·00 1·500 3·00 2·50 2·00 0·50 2·50 3·00 2·00 2·50 2·50 2·50 3·00 3·00 ..
Mineral matter
(non volatile).		 5·00 4·000 4·50 4·50 5·50 5·00 5·00 5·00 4·50 4·00 4·00 4·00 4·50 4·00 ..
Total solids
(by evaporation).		 11·00 5·50 7·50 7·00 7·50 5·50 7·50 8·00 6·50 6·50 6·50 6·50 7·50 7·00 ..

Cl. signifies clear. Sl. Tb., slightly turbid. Tb., turbidity somewhat more marked.

Parts per 100,000.

Description of Sample. Date when
taken.		 Time when
drawn.		 Appearance in
two-foot Tube.		 Odour when
heated
to 38°.		 Chlorine
in
Chlorides.		 Equivalent
to Sodium
Chloride.
1884.
Mohawk River, above
Diamond Woollen Mills		 Dec. 5 .. Turbid, greenish
yellow		 Faint aromatic 0·233 0·371
Hudson River, above
Lansingburg		 Nov. 12 .. Faintly turbid, light
greenish yellow		 Faint, vegetable 0·233 0·371
Troy hydrant „ 12 .. Faintly turbid, light
greenish yellow		 Faint, vegetable 0·233 0·371
Hudson River, at
Maple Island		 Dec. 6 .. Faintly turbid,
greenish yellow		 Faint, marshy 0·167 0·265
Hudson River, at
inlet		 Nov. 1 High tide Clear, light yellow Faint 0·333 0·530
Hudson River, at
inlet		 „ 1 „ Faintly turbid,
light yellow		 Faint, stale 0·333 0·530
Hudson River, at inlet „ 1 Low tide Clear, brownish
yellow		 Faint 0·366 0·583
Hudson River, at inlet „ 1 „ Turbid, brownish
yellow		 Faint 0·366 0·583
Hudson River, 50 ft.
south of inlet		 Dec. 4 High tide Slightly turbid,
brownish yellow		 Oily 0·233 0·371
Hudson River, at inlet „ 4 Low tide Turbid, brownish
yellow		 Oily 0·183 0·291
Bleecker Reservoir Nov. 1 .. Clear, faint
yellow		 .. 0·340 0·541
Bleecker Reservoir „ 1 .. Turbid, faint
yellow		 Faint, stale 0·340 0·541
Tivoli Lake „ 6 .. Faint milkiness Faint, stale 0·833 1·325
Tivoli Lake „ 6 .. Whitish, milky Faint, stale 0·833 1·325
Tivoli Lake Dec. 4 .. Turbid, greenish Faint, marshy 0·966 1·537

Parts per 100,000.

Phosphates. Nitrites. Nitrogen in
Nitrates and
Nitrites.		 Free
Ammonia.		 Albuminoid
Ammonia.		 Oxygen
absorbed
at 80° Fahr.		 Hardness equivalent to
Carbonate of lime.		 Organic
and
Volatile
Matter.		 Mineral
Matter.		 Total
Solids
dried
at 110°.
In 15
Minutes.		 In 4
hours.		 Before
Boiling.		 After
Boiling.
.. .. 0·0705 0·0044 0·0074 0·2071 0·3704 6·838 6·838 1·70 9·00 10·70
.. .. 0·0247 .. 0·0150 0·2691 0·4150 3·818 3·818 2·20 5·80 8·00
.. .. 0·0284 0·0015 0·0151 0·2750 0·4000 4·498 4·498 2·60 6·50 9·00
.. .. 0·0614 0·0014 0·0082 0·2827 0·4100 5·049 4·839 2·40 5·30 7·70
.. .. 0·0277 0·0064 0·0002 0·1670 0·3111 5·897 5·897 1·40 9·80 11·20
.. .. 0·0265 0·0038 0·0142 0·1890 0·3422 6·237 6·237 5·00 7·20 12·20
.. .. 0·0471 0·0028 0·0134 0·2180 0·3180 6·237 6·086 1·80 9·20 11·00
.. .. 0·0288 0·0050 0·0124 0·2200 0·3470 6·048 6·048 4·80 8·20 13·00
.. .. 0·0647 0·0054 0·0114 0·2509 0·4340 5·470 5·470 3·50 4·50 8·00
.. .. 0·0606 0·0064 0·0090 0·2230 0·4420 5·838 5·838 1·50 7·50 9·00
.. .. 0·0484 0·0052 0·0068 0·1511 0·2578 5·330 3·893 2·50 8·80 11·30
.. .. 0·0489 0·0046 0·0102 0·1755 0·3020 6·577 6·577 5·70 6·80 12·50
Faint trace Faint trace 0·0507 0·0184 0·0080 0·0780 0·2030 7·069 4·309 2·00 12·00 14·00
Faint trace Faint trace 0·0611 0·0198 0·0280 0·1200 0·1852 7·409 5·481 6·00 11·00 17·00
Faint trace Faint trace 0·1334 0·0380 0·0118 0·1075 0·1762 8·468 8·468 3·20 10·40 13·60

The variation in the composition of Croton water, at different seasons of the year, is exhibited by the table on p. 221, which gives the results of the semi-monthly examinations made by Dr. Elwyn Waller during the year 1885.[131]

For the results of the analyses of the water of the Hudson River, recently made by Dr. C. F. Chandler, see table, pp. 222, 223.

The rather common belief that freezing purifies water is incorrect. It is said, that the greater part of the ice supply of New York City (three millions of tons) is gathered from the Hudson River between Albany and Poughkeepsie, most being drawn within thirty miles of the former city, and therefore liable to be polluted with sewage. The average number of bacteria in one c.c. of ordinary ice is stated to approximate 400, but Hudson River ice has been found to contain nearly 2000 bacteria per c.c.[132] The number of bacteria in one c.c. of snow is usually about 9000; Hudson River snow-ice contains 20,000 per c.c.; and, although the great majority of these organisms are perfectly harmless, cases are on record where epidemics (as of gastro-enteritis) have been directly traced to the use of impure ice.