CHAPTER XIV.

WATER-SUPPLY AND DISEASE—CONCLUSIONS.

One of the most characteristic and uniform results of the direct

pollution of public water-supplies is the typhoid fever which results

among the users of the water. In the English and German cities with

almost uniformly good drinking-water, typhoid fever is already nearly

exterminated, and is decreasing from year to year. American cities

having unpolluted water-supplies have comparatively few deaths from

this cause, although the figures never go so low as in Europe, perhaps

on account of the fresh cases which are always coming in from less

healthy neighborhoods in ever-moving American communities. In other

American cities the death-rates from typhoid fever are many times what

they ought to be and what they actually are in other cities, and the

rates in various places, and in the same place at different times,

bear in general a close relation to the extent of the pollution of the

drinking-water. The power of suitable filtration to protect a city from

typhoid fever is amply shown by the very low death-rates from this

cause in London, Berlin, Breslau, and large numbers of other cities

drawing their raw water from sources more contaminated than those of

any but the very worst American supplies, and by the marked and great

reductions in the typhoid-fever death rates which have followed at once

the installation of filters at Zürich, Switzerland; Hamburg, Germany;

Lawrence, Mass., and other places.

The following is a list of the cities of 50,000 inhabitants and upward

in the United States, with deaths from typhoid fever and the sources

of their water-supplies. The deaths and populations are from the

U. S. Census for 1890; the sources of the water-supplies, from the

_American Water-Works Manual_ for the same year. Four cities of this

size—Grand Rapids, Lincoln, St. Joseph, and Des Moines—are not included

in the census returns of mortality. Two cities with less than 50,000

inhabitants with exceptionally high death-rates have been included, and

at the foot of the list are given corresponding data for some large

European cities for 1893.

TYPHOID FEVER DEATH-RATES AND WATER-SUPPLIES OF CITIES.

-----------------+-----------+--------------+-------------------------

| | Deaths from |

| | Typhoid |

| | Fever. |

City. |Population.+------+-------+ Water-supply.

| | | Per |

| |Total.|100,000|

| | |living.|

-----------------+-----------+------+-------+-------------------------

Birmingham | 26,178 | 69 | 264 |Five Mile Creek

1. Denver | 106,713 | 232 | 217 |North Platte River and

| | | | wells

2. Allegheny | 105,287 | 192 | 182 |Allegheny River

3. Camden | 58,313 | 77 | 132 |Delaware River

4. Pittsburg | 238,617 | 304 | 127 |Allegheny and Monongahela

| | | | rivers

Lawrence | 44,654 | 54 | 121 |Merrimac River

5. Newark | 181,830 | 181 | 100 |Passaic River

6. Charleston | 54,955 | 54 | 98 |Artesian wells yielding

| | | | 1,600,000 gallons daily

7. Washington | 230,392 | 200 | 87 |Potomac River

8. Lowell | 77,696 | 64 | 82 |Merrimac River

9. Jersey City | 163,003 | 134 | 82 |Passaic River

10. Louisville | 161,129 | 122 | 76 |Ohio River

11. Philadelphia | 1,046,964 | 770 | 74 |Delaware and Schuylkill

| | | | rivers

12. Chicago | 1,099,850 | 794 | 72 |Lake Michigan

13. Atlanta | 65,533 | 47 | 72 |South River

14. Albany | 94,923 | 67 | 71 |Hudson River

15. Wilmington | 61,431 | 43 | 70 |Brandywine Creek

16. St. Paul | 133,156 | 92 | 69 |Lakes

17. Troy | 60,956 | 42 | 69 |Hudson River and

| | | | impounding reservoirs

18. Los Angeles | 50,395 | 34 | 67 |Los Angeles River and

| | | | springs

19. Nashville | 76,168 | 49 | 64 |Cumberland River

20. Cleveland | 261,353 | 164 | 63 |Lake Erie

21. Richmond | 81,388 | 50 | 61 |James River

22. Hartford | 53,230 | 32 | 60 |Connecticut River and

| | | | impounding reservoir

23. Fall River | 74,398 | 44 | 59 |Watupa Lake

24. Minneapolis | 164,738 | 94 | 57 |Mississippi River

25. San Francisco| 298,997 | 166 | 56 |Lobus Creek, Lake Merced,

| | | | and mountain streams

26. Indianapolis | 105,436 | 57 | 54 |White River

27. Cincinnati | 296,908 | 151 | 51 |Ohio River

28. Memphis | 64,495 | 33 | 51 |Artesian Wells

29. Reading | 58,661 | 29 | 49 |Maiden Creek and Springs

30. Baltimore | 434,439 | 202 | 47 |Impounding reservoir

31. Omaha | 140,452 | 63 | 45 |Missouri River

32. Columbus | 88,150 | 38 | 43 |Surface-water and wells

33. Providence | 132,146 | 53 | 40 |Pawtuxet River

34. Kansas City | 132,716 | 53 | 40 |Missouri River

35. Rochester | 133,896 | 53 | 39 |Hemlock and Candice lakes

36. Evansville | 50,756 | 20 | 39 |Ohio River

37. Boston | 448,477 | 174 | 39 |Impounding reservoirs

38. Toledo | 81,434 | 29 | 36 |Maumee River

39. Cambridge | 70,028 | 24 | 34 |Impounding reservoir

40. St. Louis | 451,770 | 145 | 32 |Mississippi River

41. Scranton | 75,215 | 24 | 32 |Impounding reservoir

42. Buffalo | 255,664 | 80 | 31 |Niagara River

43. Milwaukee | 204,468 | 61 | 30 |Lake Michigan

44. New Haven | 81,298 | 22 | 27 |Impounding reservoir

45. Worcester | 84,655 | 22 | 26 |Impounding reservoir

46. Paterson | 78,347 | 20 | 26 |Passaic River

| | | | (higher up)

47. Dayton | 61,220 | 15 | 25 |Wells

48. Brooklyn | 806,343 | 194 | 24 |Wells, ponds, and

| | | | impounding reservoirs

49. New York | 1,515,301 | 348 | 23 |Impounding reservoir

50. Syracuse | 88,143 | 18 | 20 |Impounding reservoir

| | | | and springs

51. New Orleans | 242,039 | 45 | 19 |Mississippi River

52. Detroit | 205,876 | 40 | 19 |Detroit River

53. Lynn | 55,727 | 9 | 16 |Impounding reservoir

54. Trenton | 57,458 | 9 | 16 |Delaware River

| | | |

London | 4,306,411 | 719 | 17 |Filtered Thames and Lea

| | | | rivers and 1/4 from

| | | | wells

Glasgow | 667,883 | 138 | 20 |Loch Katrine

Paris | 2,424,705 | 609 | 25 |Spring water

Amsterdam | 437,892 | 69 | 16 |Filtered dune-water

Rotterdam | 222,233 | 12 | 5 |Filtered Maas River

Hague | 169,828 | 3 | 2 |Filtered dune-water

Berlin | 1,714,938 | 161 | 9 |Filtered Havel and Spree

| | | | rivers

Hamburg | 634,878 | 115 | 18 |Filtered Elbe River

Breslau | 353,551 | 37 | 11 |Filtered Oder River

Dresden | 308,930 | 14 | 5 |Ground-water

Vienna | 1,435,931 | 104 | 7 |Spring-water

-----------------+-----------+------+-------+-------------------------

Any full discussion of these data would require intimate acquaintances

with the various local conditions which it is impossible to take

up in detail here, but some of the leading facts cannot fail to be

instructive.

Each of the places having over 100 deaths per 100,000 from typhoid

fever used unfiltered river-water. Lower in the list, but still very

high, Charleston, said to have been supplied only from artesian wells,

had an excessive rate; but the reported water-consumption is so low as

to suggest that private wells or other means of supply were in common

use. Chicago and Cleveland both drew their water from lakes where they

were contaminated by their own sewage. St. Paul’s supply came from

ponds, of which I do not know the character. With these exceptions all

of the 22 cities with over 50,000 inhabitants, at the head of the list,

had unfiltered river-water.

The cities supplied from impounding reservoirs as a rule had lower

death rates and are at the lower end of the list, together with some

cities taking their water supplies from rivers or lakes at points where

they were subject to only smaller or more remote infection. Only three

of the American cities in the list were reported as being supplied

entirely with ground-water.

It is not my purpose to make too close comparisons between the various

cities on the list; some of them may have been influenced by unusual

local conditions in 1890. Others have in one way or another improved

their water-supplies since that date, and there are several cities in

which I know the present typhoid-fever death-rates to be materially

lower than those of 1890 given in the table. On the other hand, it is

equally true that a number of cities, including some of the larger

ones, have since had severe epidemics of typhoid fever which have given

very much higher rates than those for 1890.

These fluctuations would change the order of cities in the list from

year to year; they would not change the general facts, which are as

true to-day as they were in 1890. Nearly all of the great cities of the

United States are supplied with unfiltered surface-waters, and a great

majority of the waters are taken from rivers and lakes at points where

they are polluted by sewage. The death-rates from typhoid fever in

those cities, whether they are compared with better supplied cities of

this country, or with European cities, are enormously high.

Such rates were formerly common in European cities, but they have

disappeared with better sanitary conditions. The introduction of

filters has often worked marvellous changes in Europe, and in Lawrence

the improvement in the city’s health with filtered water was prompt

and unquestionable. There is every reason to believe that the general

introduction of better water in American cities will work corresponding

revolutions; and looking at it from a merely money standpoint, the

value of the lives and the saving of the expenses of sickness will pay

handsomely when compared with the cost of good water.

The reasons for believing that cholera is caused by polluted water

are entirely similar to those in the case of typhoid fever. It was no

accident that the epidemic of cholera which caused the death of 3400

persons followed the temporary supply of unfiltered water by the East

London Water Company in 1866, while the rest of London remained nearly

free, or that the only serious outbreak of cholera in Western Europe

in 1892 was at Hamburg, which was also the only city in Germany which

used raw river-water. This latter caused the sickness of 20,000 and the

death of over 8000 people within a month, and an amount of suffering

and financial loss, with the panics which resulted, that cannot be

estimated, but that exceeded many times the cost of the filters which

have since been put in operation. Hamburg had several times before

suffered severely from cholera, and the removal of this danger was a

leading, although not the sole, motive for the construction of filters.

How little cities supplied with pure water have to dread from

cholera is shown by the experience of Altona and other suburbs of

Hamburg with good water-supplies, which had but few cases of cholera

not directly brought from the latter place, and by the experience

of England, which maintained uninterrupted commercial intercourse

with the plague-stricken city, absolutely without quarantine, and,

notwithstanding a few cases which were directly imported, the disease

gained no foothold in England.

I do not know of a single modern European instance where a city with a

good water-supply not directly infected by sewage has suffered severely

from cholera. I shall leave to others more familiar with the facts the

discussion of what happened before the introduction of modern sanitary

methods, as well as of the present conditions in Asia; although I

believe that in these cases also there is plenty of evidence as to the

part water plays in the spread of the disease.

A considerable proportion of the water-supplies of the cities of the

United States are so polluted that in case cholera should gain a

foothold upon our shores we have no ground for hoping for the favorable

experience of the English cities rather than the plague of Hamburg in

1892.

The fæces from a man contain on an average perhaps 1,000,000,000

bacteria per gram,[47] most of them being the normal bacilli of

the intestines, _Bacillus coli communis_. Assuming that a man

discharges 200 grams or about 7 ounces of fæces daily, this would give

200,000,000,000 bacteria discharged daily per person. The number of

bacteria actually found in American sewage is usually higher, often

double this number per person; but there are other sources of bacteria

in sewage, and in addition growths or the reverse may take place in the

sewers, according to circumstances.

This number of bacteria in sewage is so enormously large that the

addition of the sewage from a village or city to even a large river

is capable of affecting its entire bacterial composition. Thus taking

the population of Lowell in 1892 at 85,000, and the average daily

flow of the Merrimac at 6000 cubic feet per second, and assuming that

200,000,000,000 bacteria are discharged daily in the sewage from each

person, they would increase the number in the river by 1160

per cubic centimeter, or about 300,000 in an ordinary glass of water.

The average number found in the water eight miles below, at the intake

of the Lawrence water-works, was more than six times as great as this,

due in part to the sewage of other cities higher up.

There is every reason to believe that the bulk of these bacteria were

harmless to the people of Lawrence, who drank them; but some of them

were not. Fæces of people suffering from typhoid fever contain the

germs of that disease. What proportion of the total number of bacteria

in such fæces are injurious is not known; but assuming that one fourth

only of the total number are typhoid germs, and supposing the fæces of

one man to be evenly mixed with the whole daily average flow of the

river, it would put one typhoid germ into every glass of water at the

Lawrence intake, and at low water several times as many proportionately

would be added. This gives some conception of the dilution required to

make a polluted water safe.

One often hears of the growth of disease-germs in water, but as far

as the northern United States and Europe are concerned there is no

evidence whatever that this ever takes place. There are harmless forms

of bacteria which are capable of growing upon less food than the

disease-germs require and they often multiply in badly-polluted waters.

Typhoid-fever germs live for a longer or shorter period, and finally

die without growth. The few laboratory experiments which have seemed

to show an increase of typhoid germs in water have been made under

conditions so widely different from those of natural watercourses that

they have no value.[48]

The proportionate number of cases of typhoid fever among the users

of a polluted water varies with the number of typhoid germs in the

water. Excessive pollution causes severe epidemics or continued high

death-rates according as the infection is continued or intermittent.

Slight infection causes relatively few cases of fever. Pittsburg and

Allegheny, taking their water-supplies from below the outlets of some

of their own sewers, have suffered severely (103.2 and 127.4 deaths

from typhoid fever annually per 100,000, respectively, from 1888 to

1892). Wheeling, W. Va., with similar conditions in 1890, was even

worse, a death rate of 345 per 100,000 from this cause being reported,

while Albany had only comparatively mild epidemics from the less

directly and grossly polluted Hudson. Lawrence and Lowell, taking their

water from the Merrimac, both had for many years continued excessive

rates, increasing gradually with increasing pollution; and the city

having the most polluted source had the higher rate.

In Berlin and Altona, in winter, with open filters, epidemics of

typhoid fever followed decreased efficiency of filtration, but the

epidemics were often so mild that they would have entirely escaped

observation under present American conditions. Chicago has for years

suffered from typhoid fever, and the rate has fluctuated, as far as

reliable information can be obtained, with the fluctuations in the

pollution of the lake water. An unusual discharge of the Chicago River

results in a higher death-rate. Abandoning the shore inlet near the

mouth of the Chicago River in 1892, resulted in the following year in

a reduction of 60 per cent in the typhoid fever death-rate.[49] This

reduction shows, not that the present intakes are safe, but simply that

they are less polluted than the old ones to an extent measured by the

reduction in the death-rate.

It is not supposed that in an epidemic of typhoid fever caused by

polluted water every single person contracts the disease directly by

drinking the water. On the contrary, typhoid fever is often

communicated in other ways. If we have in the first place a thousand

cases in a city caused directly by the water, they will be followed

by a large number of other cases resulting directly from the presence

in the city of the first thousand cases. The conditions favoring this

spread may vary in different wards, resulting in considerable local

variations in the death-rates. Some persons also will suffer who did

not drink any tap-water. These facts, always noted in epidemics, afford

no ground for refusing to believe, in the presence of direct evidence,

that the water was the cause of the fever. These additional cases are

the indirect if not the direct result of the water. The broad fact that

cities with polluted water-supplies as a rule have high typhoid-fever

death-rates, and cities with good water-supplies do not (except in the

occasional cases of milk epidemics, or where they are overrun by cases

contracted in neighboring cities with bad water, as is the case with

some of Chicago’s suburbs), is at once the best evidence of the damage

from bad water and measure of its extent.

The conditions which remove or destroy the sewage bacteria in a water

tend to make it safe. The most important of them are: (1) dilution; (2)

time, allowing the bacteria to die (sunlight may aid in this process,

although effective sunshine cannot reach the lower layer of turbid

waters or through ice); (3) sedimentation, allowing them to go to

the bottom, where they eventually die; and (4) natural or artificial

filtration. In rivers, distance is mainly useful in affording time,

and also, under some conditions, in allowing opportunities for

sedimentation. Thus a distance of 500 miles requires a week for water

travelling three miles an hour to pass, and will allow very important

changes to take place. The old theory that water purifies itself

in running a certain distance has no adequate foundation as far as

bacteria are concerned. Some purification takes place with the time

involved in the passage, but its extent has been greatly overestimated.

The time required for the bacteria to die simply from natural causes

is considerable; certainly not less than three or four weeks can

be depended upon with any confidence. In storage reservoirs this

action is often considerable, and it is for this reason that American

water-supplies from large storage reservoirs are, as a rule, much more

healthy than those drawn from rivers or polluted lakes, even when the

sources of the former are somewhat polluted. The water-supplies of New

York and Boston may be cited as examples. In many other water-works

operations the entire time from the pollution to the consumption of

the water is but a few days or even less, and time does not materially

improve water in this period.

Sedimentation removes bacteria only slowly, as might be expected from

their exceedingly small size; and in addition their specific gravity

probably is but slightly greater than that of water. The Lawrence

reservoir, holding from 10 to 14 days’ supply, effected, by the

combined effect of time and sedimentation, a reduction of 90 per cent

of the bacteria in the raw water. In spite of this the city suffered

severely and continuously from fever. It would probably have suffered

even more, however, had it not been for this reduction. Nothing is

known of the removal of bacteria by sedimentation from flowing rivers,

but, considering the slowness with which the process takes place in

standing water, it is evident that we cannot hope for very much in

streams, and especially rapid streams, where the opportunities for

sedimentation are still less favorable.

Filtration as practiced in Europe removes promptly and certainly a very

large proportion of the bacteria—probably, under all proper conditions,

over 99 per cent, and is thus much more effective in purification

than even weeks of storage or long flows in rivers. The places using

filtered water have, in general, extremely low death-rates from typhoid

fever. The fever which has occurred at a few places drawing their

raw water from greatly polluted sources has resulted from improper

conditions which can be avoided, and affords no ground for doubt of the

efficiency of properly conducted filtration.

Corresponding evidence has not yet been produced in connection with

the mechanical filters which have been largely used in the United

States; but the bacterial efficiencies secured with them, under proper

conditions, and with enough coagulant, have been such as to warrant the

belief that they also will serve to greatly diminish the danger from

such infection, although they have not shown themselves equal in this

respect to sand filters.

The main point is that disease-germs shall not be present in our

drinking-water. If they can be kept out in the first place at

reasonable expense, that is the thing to do. Innocence is better

than repentance. If they cannot be kept out, we must take them out

afterwards; it does not matter much how this is done, so long as the

work is thorough. Sedimentation and storage may accomplish much, but

their action is too slow and often uncertain. Filtration properly

carried out removes bacteria promptly and thoroughly and at a

reasonable expense.

APPENDICES.

Appendix I.

RULES OF THE GERMAN GOVERNMENT IN REGARD TO THE FILTRATION OF

SURFACE-WATERS USED FOR PUBLIC WATER-SUPPLIES.

Rules somewhat similar to those of which a translation is given

below were first issued by the Imperial Board of Health in 1892.

These rules were regarded as unnecessarily rigid, and a petition was

presented to the government signed by 37 water-works engineers and

directors requesting a revision.[50] As a result a conference was

organized consisting of 14 members.[51] Köhler presided, and Koch,

Gaffsky, Werner, Günther, and Reincke represented the Imperial Board

of Health. The bacteriologists were represented by Flügge, Wolffhügel,

and Fränkel, while Beer, Fischer, Lindley, Meyer, and Piefke were the

engineer members.

This conference prepared the 17 articles given below in the first

days of January, 1894. A little later the first 16 articles were

issued to all German local authorities, signed by Bosse, minister of

the “Geistlichen,” and Haase, minister of the interior, and they are

considered as binding upon all water-works using surface-water. The

bacterial examinations were commenced April 1, 1894, by most of the

cities which had not previously had them.

Although the articles do not deal with rate of filtration, or the

precautions against snow and ice, they have a very great interest both

because they are an official expression, and on account of the personal

standing of the men who prepared them.

* * * * *

§ 1. In judging of the quality of a filtered surface-water the

following points should be especially observed:

_a_. The operation of a filter is to be regarded as satisfactory

when the filtrate contains the smallest possible number of bacteria,

not exceeding the number which practical experience has shown to be

attainable with good filtration at the works in question. In those

cases where there are no previous records showing the possibilities of

the works and the influence of the local conditions, especially the

character of the raw water, and until such information is obtained,

it is to be taken as the rule that a satisfactory filtration will

never yield an effluent with more than about 100 bacteria per cubic

centimeter.

_b_. The filtrate must be as clear as possible, and, in regard to

color, taste, temperature, and chemical composition, must be no worse

than the raw water.

§ 2. To allow a complete and constant control of the bacterial

efficiency of filtration, the filtrate from each single filter must be

examined daily. Any sudden increase in the number of bacteria should

cause a suspicion of some unusual disturbance in the filter, and should

make the superintendent more attentive to the possible causes of it.

§ 3. Filters must be so constructed that samples of the effluent

from any one of them can be taken at any desired time for the

bacteriological examination mentioned in § 1.

§ 4. In order to secure uniformity of method, the following is

recommended as the standard method for bacterial examination:

The nutrient medium consists of 10 per cent meat extract gelatine with

peptone, 10 cc. of which is used for each experiment. Two samples of

the water under examination are to be taken, one of 1 cc. and one

of 1/2 cc. The gelatine is melted at a temperature of 30° to 35° C.,

and mixed with the water as thoroughly as possible in the test-tube

by tipping back and forth, and is then poured upon a sterile glass

plate. The plates are put under a bell-jar which stands upon a piece

of blotting-paper saturated with water, and in a room in which the

temperature is about 20° C.

The resulting colonies are counted after 48 hours, and with the aid of

a lens.

If the temperature of the room in which the plates are kept is lower

than the above, the development of the colonies is slower, and the

counting must be correspondingly postponed.

If the number of colonies in 1 cc. of the water is greater than about

100, the counting must be done with the help of the Wolffhügel’s

apparatus.

§ 5. The person entrusted with the carrying-out of the bacterial

examinations must present a certificate that he possesses the necessary

qualifications, and wherever possible he shall be a regular employé of

the water-works.

§ 6. When the effluent from a filter does not correspond to the

hygienic requirements it must not be used, unless the cause of the

unsatisfactory work has already been removed during the period covered

by the bacterial examinations.

In case a filter for more than a very short time yields a poor

effluent, it is to be put out of service until the cause of the trouble

is found and corrected.

It is, however, recognized from past experience that sometimes

unavoidable conditions (high water, etc.) make it impossible, from an

engineering standpoint, to secure an effluent of the quality stated

in § 1. In such cases it will be necessary to get along with a poorer

quality of water; but at the same time, if the conditions demand it

(outbreak of an epidemic, etc.), a suitable notice should be issued.

§ 7. Every single filter must be so built that, when an inferior

effluent results, which does not conform to the requirements, it can be

disconnected from the pure-water pipes and the filtrate allowed to be

wasted, as mentioned in § 6. This wasting should in general take place,

so far as the arrangement of the works will permit it:

(1) Immediately after scraping a filter; and

(2) After replacing the sand to the original depth.

The superintendent must himself judge, from previous experience with

the continual bacterial examinations, whether it is necessary to waste

the water after these operations, and, if so, how long a time will

probably elapse before the water reaches the standard purity.

§ 8. The best sand-filtration requires a liberal area of

filter-surface, allowing plenty of reserve, to secure, under all local

conditions, a moderate rate of filtration adapted to the character of

the raw water.

§ 9. Every single filter shall be independently regulated, and the

rate of filtration, loss of head, and character of the effluent shall

be known. Also each filter shall, by itself, be capable of being

completely emptied, and, after scraping, of having filtered water

introduced from below until the sand is filled to the surface.

§ 10. The velocity of filtration in each single filter shall be capable

of being arranged to give the most favorable results, and shall be as

regular as possible, quite free from sudden changes or interruptions.

On this account reservoirs must be provided large enough to balance the

hourly fluctuation in the consumption of water.

§ 11. The filters shall be so arranged that their working shall not be

influenced by the fluctuating level of the water in the filtered-water

reservoir or pump-well.

§ 12. The loss of head shall not be allowed to become so great as

to cause a breaking through of the upper layer on the surface of

the filter. The limit to which the loss of head can be allowed to

go without damage is to be determined for each works by bacterial

examinations.

§ 13. Filters shall be constructed throughout in such a way as to

insure the equal action of every part of their area.

§ 14. The sides and bottoms of filters must be made water-tight, and

special pains must be taken to avoid the danger of passages or loose

places through which the unfiltered water on the filter might find its

way to the filtered-water channels. To this end special pains should be

taken to make and keep the ventilators for the filtered-water channels

absolutely tight.

§ 15. The thickness of the sand-layer shall be so great that under no

circumstances shall it be reduced by scraping to less than 30 cm. (=

12 inches), and it is desirable, so far as local conditions allow, to

increase this minimum limit.

Special attention must be given to the upper layer of sand, which must

be arranged and continually kept in the condition most favorable for

filtration. For this reason it is desirable that, after a filter has

been reduced in thickness by scraping and is about to be refilled, the

sand below the surface, as far as it is discolored, should be removed

before bringing on the new sand.

§ 16. Every city in the German empire using sand-filtered water is

requested to make a quarterly report of its working results, especially

of the bacterial character of the water before and after filtration,

to the Imperial Board of Health (Kaiserlichen Gesundheitsamt), which

will keep itself in communication with the commission chosen by the

water-works engineers in regard to these questions; and it is believed

that after such statistical information is obtained for a period of

about two years some farther judgments can be reached.

§ 17. The question as to the establishment of a permanent inspection

of public water-works, and, if so, under what conditions, can be best

answered after the receipt of the information indicated in § 16.

APPENDIX II.

EXTRACTS FROM “BERICHT DES MEDICINAL-INSPECTORATS DES HAMBURGISCHEN

STAATES FÜR DAS JAHR 1892.”

The following are translations from Dr. Reincke’s most valuable report

upon the vital statistics of Hamburg for 1892. I much regret that I am

unable to reproduce in full the very complete and instructive tables

and diagrams which accompany the report.

=Diarrhœa and Cholera Infantum= (page 10). “It is usually assumed that

the increase of diarrhœal diseases in summer is to be explained by

the high temperature, especially by the action of the heat upon the

principal food of infants—milk. Our observations, however, indicate

that a deeper cause must be sought.” (Tables and diagrams of deaths

from cholera infantum by months for Hamburg and for Altona with the

mean temperatures, 1871-1892.)

“From these it appears that the highest monthly mortality of each year

in Hamburg occurred 7 times in July, 13 times in August, and 3 times

in September, and substantially the same in Altona. If one compares

the corresponding temperatures, it is found that in the three years

1886, 1891, and 1892, with high September mortalities, especially the

first two of them, had their maximum temperature much earlier, in fact

earlier than usual. Throughout, the correspondence between deaths and

temperatures is not well marked. Repeated high temperatures in May and

June have never been followed by a notable amount of cholera infantum,

although such periods have lasted for a considerable time. For example,

toward the end of May, 1892, for a long time the temperature was higher

than in the following August, when the cholera infantum appeared.

“The following observations are still more interesting. As is seen

from the diagram, in addition to the annual rise in summer there is

also a smaller increase in the winter, which is especially marked

in Altona. In 1892 this winter outbreak was greater than the summer

one, and nearly as great in 1880 and in 1888. The few years when

this winter increase was not marked, 1876-7, 1877-8, 1881-2, 1883-4,

were warm winters in which the mean temperature did not go below the

freezing-point. It is also to be noted that the time of this winter

outbreak is much more variable than that of the summer one. In 1887 the

greatest mortality was in November; in 1889 in February; in other years

in December or January, and in Altona, in 1886 and 1888, in March,

which is sufficient evidence that it was not the result of Christmas

festivities.

“Farther, the winter diarrhœa of Hamburg and of Altona are not parallel

as is the case in summer. In Hamburg the greatest mortality generally

comes before New Year’s; in Altona one to two months later.

“In Bockendahl’s Generalbericht über das öffentliche Gesundheitswesen

der Provinz Schleswig-Holstein für das Jahr 1870, page 10, we read:

‘Yet more remarkable was an epidemic of cholera infantum in Altona

in February which proved fatal to 43 children. These cases were

distributed in every part of the city, and could not be explained

by the health officer until he ascertained that the water company

had supplied unfiltered water to the city. This occurred for a few

days only in January, and was the only time in the whole year that

unfiltered Elbe water was delivered. However little reason there may

be to believe that there was a connection between these circumstances,

future interruptions of the service of filtered water should be most

critically watched, as only in this way can reliable conclusions be

reached. Without attempting to draw any scientific conclusions from

the fact, I cannot do less than record that, prior to the outbreak

of cholera on August 20, 1871, unfiltered together with filtered

water had been supplied to the city August 11 to 18. The action of

the authorities was then justified when they forbade in future the

supply of unfiltered water except in cases of most urgent necessity,

as in case of general conflagration; and in such a case, or in case of

interruption due to broken pipes, that the public should be suitably

warned.’

“The author of this paragraph, Dr. Kraus, became later the health

officer of Hamburg, and in an opinion written by him in 1874, and now

before me, he most earnestly urged the adoption of sand-filtration in

Hamburg, and cites the above observations in support of his position.

In the annual report of vital statistics of Hamburg for 1875 he says

that it is quite possible that the addition of unfiltered Elbe water

to milk is the cause of the high mortality from cholera infantum, as

compared with London, and this idea was often afterward expressed by

him. Since then so much evidence has accumulated that his view may

fairly be considered proved.

“For the information of readers not familiar with local conditions,

a mention of the sources of the water-supplies up to the present

time used by Hamburg and Altona will be useful. Both cities take

their entire water-supplies from the Elbe—Altona from a point about 7

miles below the discharge of the sewage of both cities, Hamburg from

about 7 miles above. The raw water at Altona is thus polluted by the

sewage from the population of both cities, having now together over

700,000 inhabitants, and contains in general 20,000 to 40,000 or more

bacteria per cubic centimeter. The raw water of Hamburg has, however,

according to the time of year and tide, from 200 to 5000, but here also

occasionally much higher numbers are obtained when the ebb tide carries

sewage up to the intake. How often this takes place is not accurately

known, but most frequently in summer when the river is low, more rarely

in winter and in times of flood. Recent bacterial examinations show

that it occurs much more frequently than was formerly assumed from

float experiments. This water is pumped directly to the city raw, while

that for Altona is carefully filtered.

“Years ago I expressed the opinion that the repeated typhoid epidemics

in Altona stood in direct connection with disturbances of the action

of the filters by frost, which result in the supply of insufficiently

purified water. Wallichs in Altona has also come to this conclusion

as a result of extended observation, and recently Robert Koch has

explained the little winter epidemic of cholera in Altona in the same

way, thus supporting our theory. When open filters are cleaned in cold,

frosty weather the bacteria in the water are not sufficiently held back

by the filters. Such disturbances of filtration not only preceded the

explosive epidemics of typhoid fever of 1886, 1887, 1888, 1891, and

1892, and the cholera outbreaks of 1871 and 1893, but also the winter

outbreaks of cholera infantum which have been so often repeated. It

cannot be doubted that these phenomena bear the relation to each other

of cause and effect. It is thus explained why in the warm winters no

such outbreaks have taken place, and also why the cholera infantum in

winter is not parallel in Hamburg and Altona.

* * * * *

“A farther support of this idea is furnished by Berlin, where in the

same way frost has repeatedly interfered with filtration. In the

following table are shown the deaths from diarrhœa and cholera infantum

for a few winter periods having unusual increases in mortality in

comparison with the bacteria in the water-supply.” (These tables show

that in March, 1886, March, 1888, February-March, 1889, and February,

1891, high numbers of bacteria resulted from frost disturbance at

the Stralau works, and in every case they were followed by greatly

increased death-rates from diarrhœal diseases.—A. H.)

“No one who sees this exhibition can doubt that here also the supply

of inadequately purified water has every time cost the lives of many

children.” (100 to 400 or more each time.—A. H.) “Even more conclusive

is the evidence, published by the Berlin Health Office, that this

increase was confined to those parts of the city supplied from Stralau”

(with open filters.—A. H.), “and that the parts supplied from the

better Tegel works took no part in the outbreaks, which was exactly

the case with the well-known typhoid epidemic of February and March,

1889.... It was also found that those children nursed by their mothers

or by wet-nurses did not suffer, but only those fed on the milk of

animals or other substitutes, and which in any case were mixed with

more or less water.”

Under =Cholera=, page 28, he says: “The revised statistics here given

differ slightly from preliminary figures previously issued and widely

published.” (The full tables, which cannot be here reproduced, show

16,956 cases and 8605 deaths. 8146 of the deaths occurred in the month

ending September 21. Of these, 1799 were under 5 years old; 776 were 5

to 15; 744, 15 to 25; 3520, 25 to 50; 1369, 50 to 70; and 397 over 70

or of unknown age. The bulk of the cases were thus among mature people,

children, except very young children, suffering the least severely of

any age class.)

“The epidemic began on August 16, in the port where earlier outbreaks

have also had their origin. The original source of the infection

has not been ascertained with certainty, but was probably from one

of two sources. Either it came from certain Jews, just arrived from

cholera-stricken Russia, who were encamped in large numbers near the

American pier, or the infection came from Havre, where cholera had been

present from the middle of July. Perhaps the germs came in ships in

water-ballast which was discharged at Hamburg, which is so much more

probable, as the sewage of Havre is discharged directly into the docks.

“It is remarkable that in Altona, compared to the total number of

cases, very few children had cholera, while in the epidemic of 1871 the

children suffered severely. This may be explained by supposing that the

cholera of 1892 in Altona was not introduced by water, but by other

means of infection....

“It is well known that the drinking-water (of Hamburg) is supposed to

have been from the first the carrier of the cholera-germs. In support

of this view the following points are especially to be noted:

“1. The explosive rapidity of attack. The often-compared epidemic

in Munich in 1854, which could not have come from the water is

characteristically different in that its rise was much slower and was

followed by a gradual decline. In Hamburg, with six times as large a

population, the height of the epidemic was reached August 27, only 12

days after the first cases of sickness, while in Munich 25 days were

required. In Hamburg also the bulk of the cases were confined to 12

days, from August 25 to September 5, while in Munich the time was twice

as long.

“2. The exact limit of the epidemic to the political boundary between

Hamburg and Altona and Wandsbeck, which also agrees with the boundary

between the respective water-supplies, while other differences were

entirely absent. Hamburg had for 1000 inhabitants 26.31 cases and 13.39

deaths, but Altona only 3.81 cases and 2.13 deaths, and Wandsbeck 3.06

cases and 2.09 deaths.

“3. The old experience of cholera in fresh-water ports, and the analogy

of many earlier epidemics. In this connection the above-mentioned

epidemic of 1871 in Altona has a special interest, even though some

of the conclusions of Bockendahl’s in his report of 1871 are open to

objection. First there were 3 deaths August 3, which were not at once

followed by others. Then unfiltered Elbe water was supplied August 11

to 18. On the 19th an outbreak of cholera extended to all parts of

the city, which reached its height August 25 and 26, and afterwards

gradually decreased. In all 105 persons died of cholera and 186 (179 of

them children) of diarrhœa. In Hamburg, four times as large, only 141

persons died of cholera at this time, thus proportionately a smaller

number. The conditions were then the reverse of those of 1892, an

infection of the Altona water and a comparative immunity in Hamburg.

“It is objected that the cholera-germs were not found in the water

in 1892. To my knowledge they were first looked for, and then

with imperfect methods, in the second half of September. In the

after-epidemics at Altona, they were found in the river-water by R.

Koch by the use of better methods.

“It is quite evident that the germs were also distributed by other

methods than by the city water, especially by dock-laborers who became

infected while at their work and thus set up little secondary epidemics

where they went or lived.... These laborers and sailors, especially on

the smaller river-boats, had an enormously greater proportionate amount

of cholera than others.... These laborers do not live exclusively near

the water, but to a measure in all parts of the city.” (And in Altona

and Wandsbeck.—A. H.)

“Altona had 5 deaths from cholera December 25 to January 4, and 19

January 23 to February 11, and no more. As noted above, this is

attributed to the water-supply, and to defective filtration in presence

of frost....

“The cholera could never have reached the proportion which it did, had

the improvements in the drinking-water been earlier completed.”

Further accounts of the water-supplies of Altona and of Hamburg and of

the new filtration works at the latter city are given in Appendices VII

and VIII.

APPENDIX III.

METHODS OF SAND-ANALYSIS.

(From the Annual Report of the Massachusetts State Board of Health for

1892.)

A knowledge of the sizes of the sand-grains forms the basis of many of

the computations. This information is obtained by means of mechanical

analyses. The sand sample is separated into portions having grains

of definite sizes, and from the weight of the several portions the

relative quantities of grains of any size can be computed.

=Collection of Samples.=—In shipping and handling, samples of sand

are best kept in their natural moist condition, as there is then no

tendency to separation into portions of unequal-sized grains. Under no

circumstances should different materials be mixed in the same sample.

If the material under examination is not homogeneous, samples of each

grade should be taken in separate bottles, with proper notes in regard

to location, quantity, etc. Eight-ounce wide-necked bottles are most

convenient for sand samples, but with gravels a larger quantity is

often required. Duplicate samples for comparison after obtaining the

results of analyses are often useful.

=Separation into Portions having Grains of Definite Sizes.=—Three

methods are employed for particles of different sizes—hand-picking

for the stones, sieves for the sands, and water elutriation for the

extremely fine particles. Ignition, or determination of albuminoid

ammonia, might be added for determining the quantity of organic matter,

which, as a matter of convenience, is assumed to consist of particles

less than 0.01 millimeter in diameter.

The method of hand-picking is ordinarily applied only to particles

which remain on a sieve two meshes to an inch. The stones of this size

are spread out so that all are in sight, and a definite number of the

largest are selected and weighed. The diameter is calculated from the

average weight by the method to be described, while the percentage is

reckoned from the total weight. Another set of the largest remaining

stones is then picked out and weighed as before, and so on until the

sample is exhausted. With a little practice the eye enables one to pick

out the largest stones quite accurately.

With smaller particles this process becomes too laborious, on account

of the large number of particles, and sieves are therefore used

instead. The sand for sifting must be entirely free from moisture, and

is ordinarily dried in an oven at a temperature somewhat above the

boiling-point. The quantity taken for analysis should rarely exceed

100-200 grams. The sieves are made from carefully-selected brass-wire

gauze, having, as nearly as possible, square and even-sized meshes. The

frames are of metal, fitting into each other so that several sieves can

be used at once without loss of material. It is a great convenience to

have a mechanical shaker, which will take a series of sieves and give

them a uniform and sufficient shaking in a short time; but without this

good results can be obtained by hand-shaking. A series which has proved

very satisfactory has sieves with approximately 2, 4, 6, 10, 20, 40,

70, 100, 140, and 200 meshes to an inch; but the exact numbers are of

no consequence, as the actual sizes of the particles are relied upon,

and not the number of meshes to an inch.

It can be easily shown by experiment that when a mixed sand is shaken

upon a sieve the smaller particles pass first, and as the shaking

is continued larger and larger particles pass, until the limit is

reached when almost nothing will pass. The last and largest particles

passing are collected and measured, and they represent the separation

of that sieve. The size of separation of a sieve bears a tolerably

definite relation to the size of the mesh, but the relation is not to

be depended upon, owing to the irregularities in the meshes and also

to the fact that the finer sieves are woven on a different pattern

from the coarser ones, and the particles passing the finer sieves are

somewhat larger in proportion to the mesh than is the case with the

coarser sieves. For these reasons the sizes of the sand-grains are

determined by actual measurements, regardless of the size of the mesh

of the sieve.

It has not been found practicable to extend the sieve-separations to

particles below 0.10 millimeter in diameter (corresponding to a sieve

with about 200 meshes to an inch), and for such particles elutriation

is used. The portion passing the finest sieve contains the greater

part of the organic matter of the sample, with the exception of roots

and other large undecomposed matters, and it is usually best to remove

this organic matter by ignition at the lowest possible heat before

proceeding to the water-separations. The loss in weight is regarded as

organic matter, and calculated as below 0.01 millimeter in diameter.

In case the mineral matter is decomposed by the necessary heat, the

ignition must be omitted, and an approximate equivalent can be obtained

by multiplying the albuminoid ammonia of the sample by 50.[52] In this

case it is necessary to deduct an equivalent amount from the other fine

portions, as otherwise the analyses when expressed in percentages would

add up to more than one hundred.

Five grams of the ignited fine particles are put in a beaker 90

millimeters high and holding about 230 cubic centimeters. The beaker

is then nearly filled with distilled water at a temperature of 20° C.,

and thoroughly mixed by blowing into it air through a glass tube. A

larger quantity of sand than 5 grams will not settle uniformly in the

quantity of water given, but less can be used if desired. The rapidity

of settlement depends upon the temperature of the water, so that it is

quite important that no material variation in temperature should occur.

The mixed sand and water is allowed to stand for fifteen seconds, when

most of the supernatant liquid, carrying with it the greater part of

the particles less than 0.08 millimeter, is rapidly decanted into a

suitable vessel, and the remaining sand is again mixed with an equal

amount of fresh water, which is again poured off after fifteen seconds,

carrying with it most of the remaining fine particles. This process is

once more repeated, after which the remaining sand is allowed to drain,

and is then dried and weighed, and calculated as above 0.08 millimeter

in diameter. The finer decanted sand will have sufficiently settled

in a few minutes, and the coarser parts at the bottom are washed back

into the beaker and treated with water exactly as before, except that

one minute interval is now allowed for settling. The sand remaining

is calculated as above 0.04 millimeter, and the portion below 0.04 is

estimated by difference, as its direct determination is very tedious,

and no more accurate than the estimation by difference when sufficient

care is used.

=Determination of the Sizes of the Sand-grains.=—The sizes of the

sand-grains can be determined in either of two ways—from the weight of

the particles or from micrometer measurements. For convenience the size

of each particle is considered to be the diameter of a sphere of equal

volume. When the weight and specific gravity of a particle are known,

the diameter can be readily calculated. The volume of a sphere is

1/6π_d_³, and is also equal to the weight divided by the specific

gravity. With the Lawrence materials the specific gravity is uniformly

2.65 within very narrow limits, and we have _w_/2.65 = 1/6π_d_³.

Solving for _d_ we obtain the formula _d_ =.9∛_w_, where _d_

is the diameter of a particle in millimeters and _w_ its weight in

milligrams. As the average weight of particles, when not too small,

can be determined with precision, this method is very accurate, and

altogether the most satisfactory for particles above 0.10 millimeter;

that is, for all sieve separations. For the finer particles the method

is inapplicable, on account of the vast number of particles to be

counted in the smallest portion which can be accurately weighed, and

in these cases the sizes are determined by micrometer measurements.

As the sand-grains are not spherical or even regular in shape,

considerable care is required to ascertain the true mean diameter. The

most accurate method is to measure the long diameter and the middle

diameter at right angles to it, as seen by a microscope. The short

diameter is obtained by a micrometer screw, focussing first upon the

glass upon which the particle rests and then upon the highest point to

be found. The mean diameter is then the cube root of the product of the

three observed diameters. The middle diameter is usually about equal

to the mean diameter, and can generally be used for it, avoiding the

troublesome measurement of the short diameters.

The sizes of the separations of the sieves are always determined from

the very last sand which passes through in the course of an analysis,

and the results so obtained are quite accurate. With the elutriations

average samples are inspected, and estimates made of the range in

size of particles in each portion. Some stray particles both above

and below the normal sizes are usually present, and even with the

greatest care the result is only an approximation to the truth; still,

a series of results made in strictly the same way should be thoroughly

satisfactory, notwithstanding possible moderate errors in the absolute

sizes.

=Calculation of Results.=—When a material has been separated into

portions, each of which is accurately weighed, and the range in the

sizes of grains in each portion determined, the weight of the particles

finer than each size of separation can be calculated, and with enough

properly selected separations the results can be plotted in the form of

a diagram, and measurements of the curve taken for intermediate points

with a fair degree of accuracy. This curve of results may be drawn upon

a uniform scale, using the actual figures of sizes and of per cents by

weight, or the logarithms of the figures may be used in one or both

directions. The method of plotting is not of vital importance, and

the method for any set of materials which gives the most easily and

accurately drawn curves is to be preferred. In the diagram published

in the Report of the Mass. State Board of Health for 1891, page 430,

the logarithmic scale was used in one direction, but in many instances

the logarithmic scale can be used to advantage in both directions. With

this method it has been found that the curve is often almost a straight

line through the lower and most important section, and very accurate

results are obtained even with a smaller number of separations.

=Examples of Calculation of Results.=—Following are examples of

representative analyses, showing the method of calculation used with

the different methods of separation employed with various materials.

I. ANALYSIS OF A GRAVEL BY HAND-PICKING, 11,870 GRAMS TAKEN FOR

ANALYSIS.

--------+---------+-----------+-----------+-------------+-------+--------

Number | Total | Average | Estimated |Corresponding| Total |Per Cent

of |Weight of| Weight of | Weight of | Size. | Weight| of

Stones | Portion.| Stones. | Smallest | Millimeters.| of |Total

in | Grams. |Milligrams.| Stones. | |Stones |Weight

Portion.| | |Milligrams.| |Smaller|Smaller

(Largest| | | | | than | than

Selected| | | | | this | this

Stones.)| | | | | Size. | Size.

--------+---------+-----------+-----------+-------------+-------+--------

| .... | .... | .... | .... |11,870 |=100=

10 | 3,320 | 332,000 | 250,000 | =56= | 8,550 | =72=

10 | 1,930 | 193,000 | 165,000 | =49= | 6,620 | =56=

10 | 1,380 | 138,000 | 124,000 | =45= | 5,240 | =44=

20 | 2,200 | 110,000 | 93,000 | =41= | 3,040 | =26=

20 | 1,520 | 76,000 | 64,000 | =36= | 1,520 | =13=

20 | 1,000 | 50,000 | 36,000 | =30= | 520 | =4.4=

20 | 460 | 23,000 | 10,000 | =20= | 60 | =.5=

10 | 40 | 4,000 | 2,000 | =11= | 20 | =.2=

Dust | 20 | .... | .... | .... | .... | ....

--------+---------+-----------+-----------+-------------+-------+--------

The weight of the smallest stones in a portion given in the fourth

column is estimated in general as about half-way between the average

weight of all the stones in that portion and the average weight of the

stones in the next finer portion.

The final results are shown by the figures in full-faced type in the

last and third from the last columns. By plotting these figures we

find that 10 per cent of the stones are less than 35 millimeters in

diameter, and 60 per cent are less than 51 millimeters. The “uniformity

coefficient,” as described below, is the ratios of these numbers, or

1.46, while the “effective size” is 35 millimeters.

II. ANALYSIS OF A SAND BY MEANS OF SIEVES.

A portion of the sample was dried in a porcelain dish in an air-bath.

Weight dry, 110.9 grams. It was put into a series of sieves in a

mechanical shaker, and given one hundred turns (equal to about seven

hundred single shakes). The sieves were then taken apart, and the

portion passing the finest sieve weighed. After noting the weight, the

sand remaining on the finest sieve, but passing all the coarser sieves,

was added to the first and again weighed, this process being repeated

until all the sample was upon the scale, weighing 110.7 grams, showing

a loss by handling of only 0.2 gram. The figures were as follows:

-------+------------+--------+---------

| Size of | |

| Separation |Quantity|Per Cent

Sieve | of this | of Sand| of

Marked.| Sieve. |Passing.| Total

|Millimeters.|Grams. | Weight.

-------+------------+--------+---------

190 | =.105= | .5 | =.5=

140 | =.135= | 1.3 | =1.2=

100 | =.182= | 4.1 | =3.7=

60 | =.320= | 23.2 | =21.0=

40 | =.46= | 56.7 | =51.2=

20 | =.93= | 89.1 | =80.5=

10 | =2.04= | 104.6 | =94.3=

6 | =3.90= | 110.7 | =100.0=

-------+------------+--------+--------

Plotting the figures in heavy-faced type, we find from the curve that

10 and 60 per cent respectively are finer than .25 and .62 millimeter,

and we have for effective size, as described above, .25, and for

uniformity coefficient 2.5.

III. ANALYSIS OF A FINE MATERIAL WITH ELUTRIATION.

The entire sample, 74 grams, was taken for analysis. The sieves used

were not the same as those in the previous analysis, and instead of

mixing the various portions on the scale they were separately weighed.

The siftings were as follows:

Remaining on sieve marked 10, above 2.2 millimeters 1.5 grams

Remaining on sieve marked 20, above .98 millimeters 7.0 grams

Remaining on sieve marked 40, above .46 millimeters 22.0 grams

Remaining on sieve marked 70, above .24 millimeters 20.2 grams

Remaining on sieve marked 140, above .13 millimeters 9.2 grams

Passing sieve 140, below .13 millimeters 14.1 grams

The 14.1 grams passing the 140 sieve were thoroughly mixed, and one

third, 4.7 grams, taken for analysis. After ignition just below a red

heat in a radiator, the weight was diminished by 0.47 gram. The portion

above .08 millimeter and between .04 and .08 millimeter, separated as

described above, weighed respectively 1.27 and 1.71 grams, and the

portion below .04 millimeter was estimated by difference [4.7 - (0.47

+ 1.27 + 1.71)] to be 1.25 grams. Multiplying these quantities by 3,

we obtain the corresponding quantities for the entire sample, and the

calculation of quantities finer than the various sizes can be made as

follows:

-----------------------+-------+------------+-------------+-----------

| | Size of |Weight of all|Per Cent by

|Weight.| Largest | the Finer | Weight of

Size of Grain. | Grams.| Particles. | Particles. | all Finer

| |Millimeters.| Grams. | Particles.

-----------------------+-------+------------+-------------+-----------

Above 2.20 millimeters | 1.50 | .... | 74.00 | =100=

.98-2.20 millimeters | 7.00 | =2.20= | 72.50 | =98=

.46- .98 millimeters | 22.00 | =.98= | 65.50 | =89=

.24- .46 millimeters | 20.20 | =.46= | 43.50 | =60=

.13- .24 millimeters | 9.20 | =.24= | 23.30 | =32=

.08- .13 millimeters | 3.81 | =.13= | 14.10 | =19=

.04- .08 millimeters | 5.13 | =.08= | 10.29 | =14=

.01- .04 millimeters | 3.75 | =.04= | 5.16 | =7=

Loss on ignition | | | |

(assumed to be less | | | |

than .01 millimeter)| 1.41 | =.01= | 1.41 | =1.9=

-----------------------+-------+------------+-------------+-----------

By plotting the heavy-faced figures we find that 10 and 60 per cent are

respectively finer than .055 and .46 millimeter, and we have effective

size .055 millimeter and uniformity coefficient 8.

* * * * *

The effective size and uniformity coefficient calculated in this way

have proved to be most useful in various calculations, particularly

in estimating the friction between the sands and gravels and water.

The remainder of the article in the Report of the Mass. State Board

of Health is devoted to a discussion of these relations which were

mentioned in Chapter III of this volume.

APPENDIX IV.

FILTER STATISTICS.

STATISTICS OF OPERATION OF SAND FILTERS.

------------+----------+---------+-------+-------+---------+-------+----------

| |Total | | Area | Average |Area of|Period,

| |Quantity | | of | Daily |Filter |

| |of Water | |Filters| Yield, |Surface|Million

| |filtered |Million|in use,| |cleaned|Gallons

Place. | Year | for |Gallons| | Million |in One |per Acre

| Ending. |One Year.| Daily.| Acres.| Gallons | Year, |filtered

| | Million | | |per Acre.| |between

| | Gallons.| | | |Acres. |Scrapings.

------------+----------+---------+-------+-------+---------+-------+----------

Altona |Mar., 1895| 1,620 | 4.44 | 3.08 | 1.45 | 31.0 | 52

|Mar., 1896| 1,730 | 4.75 | 3.08 | 1.55 | 48.5 | 36

|Mar., 1897| 1,960 | 5.40 | 3.08 | 1.75 | 44.0 | 45

|Mar., 1898| 1,940 | 5.30 | 3.08 | 1.72 | 36.5 | 53

Amsterdam, |Dec., 1894| 1,390 | 3.80 | 5.43 | 0.71 | 23 | 62

River |Dec., 1896| 1,490 | 4.08 | 5.43 | 0.75 | 48 | 31

|Dec., 1897| 1,600 | 4.40 | 5.43 | 0.81 | 30 | 53

Amsterdam, |Dec., 1894| 2,330 | 6.40 | 4.94 | 1.29 |116 | 20

Dunes |Dec., 1896| 2,360 | 6.50 | 4.75 | 1.37 | 90 | 26

|Dec., 1897| 2,290 | 6.25 | 4.75 | 1.31 |109 | 21

Ashland, |Feb., 1897| 398 | 1.09 | 0.50 | 2.18 | 4.83 | 83

Wis. | | | | | | |

Berlin, |Mar., 1896| 13,000 | 35.60 | 25.10 | 1.42 | |

total |Mar., 1897| 12,900 | 35.40 | 25.10 | 1.40 | |

|Mar., 1898| 13,200 | 36.20 | 27.00 | 1.34 | |

Bremen |Mar., 1895| 1,190 | 3.27 | 2.51 | 1.31 | 50 | 24

|Mar., 1896| 1,220 | 3.34 | 3.21 | 1.04 | 32.5 | 38

|Mar., 1897| 1,280 | 3.50 | 3.21 | 1.09 | 25.2 | 50

|Mar., 1898| 1,400 | 4.10 | 3.21 | 1.28 | 34.0 | 41

Breslau |Mar., 1895| 2,840 | 7.80 | 5.12 | 1.52 | 45 | 64

|Mar., 1896| 2,960 | 8.10 | 5.12 | 1.58 | 40.0 | 74

|Mar., 1897| 2,990 | 8.20 | 5.12 | 1.60 | 37 | 81

|Mar., 1898| 3,060 | 8.40 | 5.12 | 1.64 | 43 | 71

Brunn |Dec., 1896| 1,110 | 3.04 | 1.62 | 1.87 | 8.6 | 128

|Dec., 1897| 1,190 | 3.25 | 1.62 | 2.00 | 9.1 | 131

Brunswick |Mar., 1895| 815 | 2.23 | 1.48 | 1.51 | 14.8 | 55

|Mar., 1896| 840 | 2.30 | 1.48 | 1.56 | 13.3 | 63

|Mar., 1897| 820 | 2.25 | 1.48 | 1.52 | 13.7 | 60

|Mar., 1898| 870 | 2.38 | 1.48 | 1.61 | 11.9 | 73

Budapest |Dec., 1892| 7,360 | 20.20 | 3.00 | 6.70 |254 | 29

Copenhagen |Dec., 1895| 2,330 | 6.40 | 2.88 | 2.22 | 45 | 52

|Dec., 1896| 2,490 | 6.80 | 2.88 | 2.35 | 52 | 48

|Dec., 1897| 2,580 | 7.10 | 2.88 | 2.47 | 54 | 48

Dordrecht |Dec., 1894| 365 | 1.00 | 0.56 | 1.79 | |

Frankfort |Dec., 1895| 310 | 0.85 | 0.37 | 2.28 | 2.9 | 107

on Oder |Dec., 1896| 325 | 0.89 | 0.37 | 2.40 | 7.4 | 44

|Dec., 1897| 356 | 0.98 | 0.37 | 2.65 | 8.8 | 41

Hamburg |Dec., 1894| 11,450 | 31.40 | 34.0 | 0.92 |350 | 33

|Dec., 1895| 11,700 | 32.10 | 34.0 | 0.94 |275 | 43

|Dec., 1896| 11,500 | 31.70 | 34.0 | 0.93 |266 | 43

|Dec., 1897| 12,000 | 32.70 | 34.0 | 0.96 |285 | 42

|Dec., 1898| 11,900 | 32.60 | 43.0 | 0.76 |246 | 48

Hudson, |Dec., 1892| 697 | 1.91 | 0.74 | 2.58 | |

N. Y. |Dec., 1893| 543 | 1.49 | 0.74 | 2.01 | |

|Dec., 1895| 535 | 1.46 | 0.74 | 1.98 | |

Ilion, N. Y.|Feb., 1899| 182 | 0.50 | 0.14 | 3.57 | 1.40 | 130

Königsberg |Mar., 1895| 1,060 | 2.90 | 2.70 | 1.07 | 38.5 | 27

|Mar., 1896| 1,085 | 2.97 | 2.70 | 1.10 | 35.0 | 31

|Mar., 1897| 1,085 | 2.97 | 2.70 | 1.10 | 41.0 | 27

|Mar., 1898| 1,140 | 3.12 | 2.70 | 1.16 | 44.0 | 26

Lawrence |Dec., 1894| 1,050 | 2.88 | 2.50 | 1.15 | 10 | 105

|Dec., 1895| 1,097 | 3.00 | 2.50 | 1.20 | 27 | 41

|Dec., 1896| 1,101 | 3.02 | 2.50 | 1.20 | 30 | 37

|Dec., 1897| 1,114 | 3.06 | 2.50 | 1.22 | 41 | 27

Liverpool |Dec., 1896| 8,520 | 23.40 | 10.92 | 2.14 |158 | 54[53]

London, all |Dec., 1892| 65,783 |180 |109.75 | 1.64 | 90 |

filters |Dec., 1893| |195 |116.00 | 1.68 | |

but not |Dec., 1894| 68,700 |188 |117.00 | 1.60 | |

including |Dec., 1895| 76,900 |210 |123.75 | 1.70 | |

ground |Dec., 1896| 72,482 |198 |123.75 | 1.60 | |

water |Dec., 1897| 73,340 |201 |125.00 | 1.61 | |

London, |Dec., 1897| 5,370 | 14.70 | 8.00 | 1.85 | |

Chelsea | | | | | | |

E. London |Dec., 1897| 18,000 | 49.00 | 31.00 | 1.58 | |

Grand |Dec., 1897| 8,560 | 23.40 | 21.75 | 1.07 | |

Junction | | | | | | |

Lambeth |Dec., 1897| 10,370 | 28.40 | 12.25 | 2.30 | |

New River |Dec., 1897| 15,750 | 43.00 | 16.50 | 2.60 | |

Southwark & |Dec., 1897| 14,800 | 40.50 | 20.50 | 1.98 | |

Vauxhall | | | | | | |

West |Dec., 1897| 8,910 | 24.30 | 15.00 | 1.61 | |

Middlesex | | | | | | |

Lübeck |Mar., 1895| 1,520 | 4.15 | 1.40 | 2.95 | 16.2 | 94

|Mar., 1896| 1,600 | 4.38 | 1.40 | 3.13 | 24.4 | 66

|Mar., 1897| 1,650 | 4.50 | 1.40 | 3.22 | 27.0 | 61

|Mar., 1898| 1,750 | 4.80 | 1.40 | 3.42 | 38.5 | 45

Magdeburg |Mar., 1895| 1880 | 5.15 | 3.76 | 1.37 | 47.5 | 40

|Mar., 1896| 1950 | 5.35 | 3.76 | 1.42 | 65.0 | 30

|Mar., 1897| 1880 | 5.15 | 3.76 | 1.37 | 59.0 | 32

|Mar., 1898| 2070 | 5.66 | 3.76 | 1.50 | 63.0 | 33

Mt. Vernon, |Dec., 1895| 493 | 1.35 | 1.10 | 1.22 | 7.3 | 68

N. Y |Dec., 1896| 608 | 1.66 | 1.10 | 1.51 | 9.2 | 66

|Dec., 1897| 808 | 2.21 | 1.10 | 2.00 | 16.6 | 49

|Dec., 1898| 933 | 2.56 | 1.10 | 2.34 | 18.4 | 51

Posen |Mar., 1895| 305 | 0.84 | 0.70 | 1.20 | 10.3 | 30

|Mar., 1896| 346 | 0.94 | 0.70 | 1.35 | 10.4 | 33

|Mar., 1897| 325 | 0.89 | 0.70 | 1.27 | 10.1 | 32

|Mar., 1898| 360 | 0.99 | 0.70 | 1.42 | 9.6 | 38

Poughkeepsie|Dec., 1892| 696 | 1.91 | 0.68 | 2.81 | 14.0 | 50

|Dec., 1893| 667 | 1.83 | 0.68 | 2.70 | 12.0 | 56

|Dec., 1894| 633 | 1.73 | 0.68 | 2.55 | 14 | 45

|Dec., 1895| 686 | 1.88 | 0.68 | 2.77 | 14 | 49

|Dec., 1896| 664 | 1.82 | 0.68 | 2.68 | 9 | 73

|Dec., 1897| 615 | 1.69 | 1.36 | 1.24 | |

|Dec., 1898| 611 | 1.67 | 1.36 | 1.23 | 10.88 | 57

Rostock |June, 1897| 560 | 1.54 | 1.11 | 1.38 | 9.3 | 60

|June, 1898| 625 | 1.71 | 1.11 | 1.55 | 9.0 | 70

Rotterdam |Dec., 1893| 4850 | 13.30 | 6.30 | 2.11 | |

Stettin |Mar., 1895| 1130 | 3.10 | 2.26 | 1.37 | 26.5 | 43

|Mar., 1896| 1030 | 2.83 | 2.26 | 1.25 | 15.5 | 66

|Mar., 1897| 980 | 2.70 | 2.26 | 1.19 | 16.1 | 61

|Mar., 1898| 1020 | 2.80 | 2.26 | 1.24 | 20.3 | 50

Stockholm |Dec., 1895| 2375 | 6.50 | 2.78 | 2.33 | 70.0 | 34

|Dec., 1896| 2500 | 6.85 | 2.78 | 2.45 | 68.0 | 37

|Dec., 1897| 2750 | 7.50 | 3.60 | 2.08 | 76.0 | 36

Stralsund |Mar., 1897| 215 | 0.59 | 1.11 | 0.53 | 16.0 | 13

|Mar., 1898| 210 | 0.58 | 1.11 | 0.51 | 17.3 | 12

Stuttgart |Mar., 1895| 1040 | 2.85 | 1.46 | 1.96 | 13.7 | 76

|Mar., 1896| 1220 | 3.34 | 1.66 | 2.04 | 17.7 | 69

|Mar., 1897| 1270 | 3.48 | 2.32 | 1.50 | 18.7 | 68

|Mar., 1898| 1320 | 3.60 | 2.32 | 1.54 | 20.2 | 65

Utrecht |Dec., 1896| 510 | 1.40 | 0.60 | 2.33 | 31 | 16

Zürich |Dec., 1891| 2010 | 5.50 | 0.84 | 6.50 | 8 | 250

|Dec., 1892| 2150 | 5.90 | 0.84 | 7.00 | 10 | 215

|Dec., 1893| 2310 | 6.38 | 1.19 | 5.35 | 13 | 177

|Dec., 1894| 2250 | 6.15 | 1.19 | 5.18 | 17 | 133

|Dec., 1895| 2460 | 6.70 | 1.19 | 5.62 | 27 | 91

|Dec., 1896| 2360 | 6.45 | 1.66 | 3.88 | 30 | 79

|Dec., 1897| 2500 | 6.84 | 1.66 | 4.13 | 35 | 71

|Dec., 1898| 2730 | 7.50 | 1.66 | 4.50 | 47 | 58

--------------+----------+---------+-------+-------+---------+-------+----------

PARTIAL LIST OF CITIES USING SAND FILTERS.

-------------------+------------------+--------+--------+------------

| When |Population.| Area | Number | Average

Place. |Built.| 1890. | of | of | Daily

| | |Filters.|Filters.|Consumption.

-------------------+------+-----------+--------+--------+------------

UNITED STATES.

Poughkeepsie. N. Y.| 1872 | 24,000 | 1.36 | 3 | 1.67

Hudson, N. Y. | 1874 | 9,970 | 0.74 | 2 | 1.50

St. Johnsbury, Vt. |187(?)| 3,857 | 0.14 | 3 | 0.70

Nantucket, Mass. | 1893 | 3,268 | 0.11 | 1 | 0.09

Lawrence, Mass. | 1893 | 44,654 | 2.50 | 1 | 3.00

Ilion, N. Y. | 1893 | 4,057 | 0.14 | 2 | 0.50

Mount Vernon, N. Y.| 1894 | 10,830 | 1.10 | 3 | 1.66

Grand Forks, N. D. | 1894 | 4,979 | 0.42 | 1 | ....

Milford, Mass. | 1895 | 9,956 | 0.25 | 1 | 0.70

Ashland, Wis. | 1895 | 9,956 | 0.50 | 3 | 1.09

Hamilton, N. Y. | 1895 | 1,744 | 0.12 | 1 | 0.03

Lambertville, N. J.| 1896 | 4,142 | 0.28 | 2 | 0.25

Far Rockaway, N. Y.| 1896 | 2,288 | 0.92 | 2 | 0.93

Red Bank, N. J. | 1897 | 500 | 0.03 | 2 | 0.10

Somersworth, N. H. | 1897 | 6,207 | 0.50 | 1 | ....

Little Falls, N. Y.| 1898 | 8,783 | 0.76 | 1 | ....

Berwyn, Penna. | 1898 | 826 | 0.52 | 3 | ....

Harrisburg, Penna. | 1899 | 1,200 | 0.12 | 2 | 0.15

Albany, N. Y. | 1899 | 94,923 | 5.60 | 8 | 11.00[54]

Rock Island, | 1899 | 13,634 | 1.20 | 3 | 3.50

Illinois | | | | |

+------+-----------+--------+--------+------------

Total | | 259,774 | 17.31 | 45 | 26.87

BRITISH COLUMBIA.

Victoria | | 16,841 | 0.82 | 3 | 1.80

SOUTH AMERICA.

Buenos Ayres | | 500,000 | 4.15 | 3 | ....

Montevidio | | | Filters reported ....

HOLLAND.

Amsterdam | | 555,821 | 10.18 | 12 | 11.20

Rotterdam | | 290,000 | 6.30 | 18 | 13.00

The Hague | | 191,000 | 2.88 | 6 | 4.20

Schiedam | | 25,300 | 1.33 | 5 | 0.68

Utrecht | | 140,000 | 0.60 | .... | 1.40

Groningen | | 57,900 | 0.59 | 2 | ....

Dordrecht | | 34,100 | 0.56 | 2 | 1.00

Leeuwarden | | 30,700 | 0.31 | 2 | ....

Vlaardingen | | .... | .... | .... | ....

Sliedrecht | | .... | .... | .... | ....

Gorinchem | | 10,000 | .... | .... | ....

Zutphen | | 18,000 | .... | .... | ....

Leyden | | 44,200 | .... | .... | ....

Enschede | | .... | .... | .... | ....

Middelburg | | 17,000 | .... | .... | ....

+------+-----------+--------+--------+------------

Total | | 1,414,021 | 22.75 | 47 | 31.48

-------------------+------+-----------+--------+--------+------------

GREAT BRITAIN.

London | | 5,030,267 | 125.00 | 120 | 200.00

Liverpool | | 790,000 | 10.92 | .... | 26.67

Dublin | | 349,000 | 5.00 | 10 | 18.00

Leeds | | 420,000 | 6.00 | 8 | 17.99

Bradford | | 436,260 | 4.62 | 6 | 13.31

Leicester | | 220,005 | 2.50 | .... | 4.75

York | | 72,083 | 2.04 | 6 | 3.00

Edinburgh | | 292,364 | 2.00 | 4 | 18.00

Darlington | | 43,000 | 1.32 | 7 | ....

Wakefield | | 36,815 | 1.25 | .... | ....

Carlisle | | 40,000 | 0.90 | .... | ....

Dumfries | | 17,821 | 0.25 | .... | ....

Accrington | | 42,000 | .... | .... | ....

Birmingham | | 680,140 | .... | .... | 19.05

Blackburn | | 130,000 | .... | .... | 4.10

Bolton | | 250,000 | .... | .... | 6.60

Chester | | 40,000 | .... | .... | ....

Halifax | | 217,000 | .... | .... | 5.18

Hereford | | 20,000 | .... | .... | ....

Middlesborough | | 187,331 | .... | .... | 11.39

Newcastle | | 320,000 | .... | .... | 14.00

Oldham | | 145,800 | .... | .... | 5.30

Oxford | | 53,000 | .... | .... | 1.59

Preston | | 113,864 | .... | .... | 4.20

Reading | | 71,558 | .... | .... | 3.00

Southampton | | 76,430 | .... | .... | 3.45

Wigan | | 60,000 | .... | .... | 1.22

Worcester | | 45,000 | .... | .... | 1.93

| +-----------+--------+--------+------------

Total | |10,199,738 | 161.80 | 161 | 382.73

GERMANY.

Hamburg | | 661,200 | 42.00 | 22 | 33.00

Berlin | | 1,746,424 | 31.45 | 55 | 36.00

Breslau | | 380,000 | 5.12 | 5 | 8.20

Magdeburg | | 217,067 | 3.76 | 11 | 5.66

Bremen | | 157,500 | 3.21 | 12 | 3.50

Altona | | 162,427 | 3.08 | 13 | 5.40

Königsberg | | 176,000 | 2.70 | 7 | 3.00

Stuttgart | | 162,516 | 2.32 | .... | 4.00

Stettin | | 145,000 | 2.26 | 9 | 3.00

Lübeck | | 70,000 | 1.40 | 6 | 4.50

Brunswick | | 100,883 | 1.48 | 4 | 2.30

Stralsund | | 30,105 | 1.11 | 6 | 0.60

Rostock | | 49,891 | 1.11 | 3 | 1.54

Lignitz | | 46,852 | 0.96 | 6 | 1.40

Posen | | 75,000 | 0.70 | 4 | 0.90

Schwerin | | 36,000 | 0.65 | 4 | 0.50

Chemnitz | | 164,743 | 0.59 | 3 | ....

Worms | | 30,000 | 0.50 | 3 | 0.64

Ratibor | | 20,729 | 0.42 | 3 |

Frankfort on Oder | | 59,161 | 0.37 | 5 | 0.89

Kiel | | 69,214 | 0.31 | | 1.50

Tilsit | | 30,000 | 0.25 | | 0.20

Brieg | | 20,154 | 0.20 | 4 |

Gluckstadt | | 6,214 | 0.14 | | 0.10

Wandsbeck | | 22,000 | 0.13 | | 0.30

| +-----------+--------+--------+------------

Total | | 4,639,080 |106.22 | 185 | 117.13

OTHER EUROPEAN FILTERS.

Warsaw | | 500,000 | 6.20 | 12 | 6.00

St. Petersburg | | 954,000 | 5.85 | 11 | 39.00

Odessa | | 380,000 | 4.75 | 5 | 8.00

Choisy le Roi and | | } 200,000 |{ 3.85 | 25 | 10.00

Neuilly sur Marne | | } |{ 2.31 | 15 |

Copenhagen | | 340,000 | 2.88 | 9 | 6.80

Stockholm | | 274,000 | 2.78 | | 7.00

Antwerp | | 240,000 | 2.10 | 8 | 2.00

Zürich | | 96,839 | 1.66 | | 7.00

Brunn | | | 1.62 | | 3.04

Constantinople, | | | 0.74 | 3 |

South side | | | | |

| +-----------+--------+--------+------------

Total | | 2,984,839 | 34.74 | 88 | 88.84

ASIA.

Blandarwada, India | | | 1.97 | 6 |

Agra, India | | | 1.37 | |

Bombay, India | | 821,000 | 1.22 | 4 |

Shanghai, China | | | 0.88 | 4 |

Hong Kong | | | 0.67 | 6 |

Yokohama, Japan | | 110,000 | 0.58 | 3 |

Calcutta, India | | 466,000 | | |

Tokyo, Japan | | | | |

Baroda, India | | | | |

Allahabad, India | | | | |

| +-----------+--------+--------+------------

Total | | 1,397,000 | 6.69 | 23 |

SUMMARY.

United States | | 259,774 | 17.31 | 45 | 26.87

British Columbia | | 16,841 | 0.82 | 3 | 1.80

South America | | 500,000 | 4.15 | 3 |

Holland | | 1,414,021 | 22.75 | 47 | 31.48

Great Britain | |10,199,738 |161.80 | 161 | 382.73

Germany | | 4,639,080 |106.22 | 185 | 117.13

Other European | | 2,984,839 | 34.74 | 88 | 88.84

countries | | | | |

Asia | | 1,397,000 | 6.69 | 23 |

| +-----------+--------+--------+------------

Total | |21,411,293 |354.48 | 555 | 648.85

-------------------+------+-----------+--------+--------+------------

LIST OF CITIES AND TOWNS USING MECHANICAL FILTERS. ARRANGED BY

POPULATIONS.

Abbreviations.--P., Pressure filters; G., Gravity filters; J., Jewell

system; N. Y., New York system; W., Warren system; C., Continental

system; Am., American system.

--------------------------+-----------+----------+-----------+

| | | Nominal |

| | | Capacity |

Place. |Population,| Filters |of Filters,|

| 1890. | First | 1899. |

| |Installed.| Million |

| | | Gallons. |

--------------------------+-----------+----------+-----------+

Denver, Col. | 108,204 | | |

Atlanta, Ga. | 65,533 | 1887 | 8 |

St. Joseph, Mo. | 52,324 | 1898 | 10.2 |

Oakland, Cal. | 48,682 | 1891 | 5 |

Kansas City, Kan. | 38,316 | 1898 | 6 |

Wilkesbarre, Pa.[55] | 37,718 | | 10 |

Norfolk, Va. | 34,871 | 1899 | 6 |

Augusta, Ga. | 33,300 | 1899 | 6 |

Quincy. Ill. | 30,494 | 1892 | 4 |

Dubuque, Iowa[56] | 30,311 | 1899 | 2 |

Terre Haute, Ind. | 30,217 | 1890 | 4 |

Elmira, N. Y. | 29,708 | 1897 | 6 |

Chattanooga, Tenn. | 29,100 | 1887 | 9 |

Davenport, Iowa | 26,872 | 1891 | 7.5 |

Little Rock, Ark. | 25,874 | 1891 | 5.5 |

Winnipeg, Mann. | 25,642 | 1887 | 1.5 |

Oshkosh, Wis. | 22,836 | 1891 | 2.4 |

Macon, Ga. | 22,746 | 1893 | 4 |

Burlington, Ia. | 22,565 | 1894 | 3.5 |

Knoxville, Tenn. | 22,535 | 1894 | 5 |

Lexington, Ky. | 21,567 | 1895 | 2 |

Kingston, N. Y. | 21,261 | 1897 | 4 |

York, Penna. | 20,793 | 1899 | 4 |

Biddeford, Maine | 20,500 | 1896 | 3 |

Newport, R. I. | 19,467 | | 4 |

Bangor, Maine | 19,103 | 1897 | 5 |

Cedar Rapids, Ia. | 18,020 | 1896 | 2.5 |

Elgin, Ill. | 17,823 | 1888 | 4.3 |

Decatur, Ill. | 16,841 | 1893 | 3 |

Belleville, Ill. | 15,361 | | 1 |

Columbia, S. C. | 15,353 | 1892 | 3 |

Keokuk, Ia. | 14,101 | 1893 | 3 |

Ottumwa, Ia. | 14,001 | 1895 | 2 |

Rock Island, Ill.[55] | 13,634 | | 2 |

Raleigh, N. C. | 12,678 | 1887 | 1 |

Shreveport, La. | 11,979 | 1889 | 1 |

New Castle, Penna | 11,600 | 1898 | 4 |

Charlotte, N. C. | 11,557 | 1896 | 1 |

Nebraska City, Neb. | 11,494 | 1891 | 0.4 |

Streator, Ill. | 11,414 | | 2 |

Hornelsville, N. Y.[58] | 10,966 | 1899 | 3 |

Augusta, Maine | 10,527 | 1887 | 0.6 |

St. Thomas, Ont. | 10,370 | 1891 | 2.5 |

Cairo, Ill. | 10,324 | 1889 | 0.8 |

Alton, Ill. | 10,294 | 1898 | 3 |

Asheville, N. C. | 10,235 | 1889 | 1 |

Greenwich, Conn. | 10,131 | 1887 | 2 |

Huntington, W. Va. | 10,108 | 1899 | 2 |

Beaver Falls, Pa. | 9,735 | | 2 |

Champaign, Ill.[57] | 9,719 | | |

Chatham, Ont. | 9,052 | 1895 | 1 |

Adrian, Mich. | 8,756 | 1899 | 1.75 |

Athens, Ga. | 8,639 | 1893 | 1 |

East Providence, R. I. | 8,422 | 1899 | 0.5 |

Winston, N. C. | 8,018 | 1895 | 0.5 |

Danville, Penna. | 7,998 | 1896 | 1 |

Clarksville, Tenn.[58] | 7,924 | 1899 | 1.5 |

Stevens Point, Wis. | 7,896 | 1889 | 0.5 |

Carlisle, Pa. | 7,620 | 1896 | 1.5 |

Calais, Me. | 7,290 | 1893 | 1.5 |

Long Branch, N. J. | 7,231 | 1888 | 3 |

Creston, Ia. | 7,200 | 1891 | 0.5 |

St. Hyacinthe, Que. | 7,016 | 1898 | 1 |

Rome, Ga.[58] | 6,957 | 1899 | 1.5 |

Westerly, R. I. | 6,813 | 1896 | 1.5 |

Merrill, Wis. | 6,809 | 1897 | 1 |

Dennison, Ohio[58] | 6,767 | 1899 | 1.25 |

Parsons, Kan. | 6,736 | 1894 | 2 |

Waterloo, Iowa | 6,674 | 1891 | 1.5 |

Somerville, N. J. | 6,417 | 1885 | 1.9 |

Athol, Mass. | 6,319 | 1888 | 1.5 |

Owego, N. Y. | 6,200 | 1887 | 1 |

Brunswick, Maine | 6,012 | 1887 | 0.6 |

Bucyrus, Ohio | 5,974 | 1887 | 0.5 |

Warren, Ohio | 5,973 | 1896 | 1.5 |

Hopkinsville, Ky. | 5,833 | 1895 | 0.5 |

Brainerd, Minn. | 5,703 | 1897 | 0.5 |

New Brighton, Pa. | 5,616 | 1889 | 0.5 |

Niagara Falls, N. Y. | 5,502 | 1896 | 4.5 |

Durham, N. C. | 5485 | 1893 | 0.9 |

Winfield, Kan. | 5184 | 1894 | 1 |

Louisiana, Mo. | 5090 | 1888 | 0.8 |

Trenton, Mo. | 5039 | 1889 | 0.4 |

Lorain, Ohio | 4863 | 1896 | 3 |

Sidney, Ohio[59] | 4850 | | |

Mexico, Mo. | 4789 | 1889 | 0.3 |

Mt. Clemens, Mich. | 4748 | 1888 | 1 |

Riverside, Cal. | 4683 | 1892 | 0.09 |

Columbus, Miss.[60] | 4559 | 1899 | 0.5 |

Winchester, Ky. | 4519 | 1894 | 0.75 |

Salisbury, N. C. | 4418 | 1889 | 0.5 |

Eufaula, Ala. | 4394 | 1897 | 0.5 |

Greenville, Tex. | 4330 | 1888 | 0.8 |

Exeter, N. H. | 4284 | 1887 | 0.114 |

Bordentown, N. J. | 4232 | 1890 | 0.5 |

Lake Forest, Ill. | 4203 | 1892 | 1 |

Henderson, N. C. | 4191 | 1899 | 0.25 |

Reading, Mass. | 4088 | 1896 | 1 |

Goldsboro, N. C. | 4017 | 1896 | 0.5 |

Rich Hill, Mo. | 4008 | 1893 | 0.5 |

Mt. Pleasant, Ia. | 3997 | 1888 | 0.5 |

Murphysboro, Ill. | 3880 | 1890 | 0.2 |

Brandon, Manitoba | 3778 | 1893 | 1 |

Danville, Ky. | 3766 | 1894 | 0.5 |

Royersford, Pa. | 3612 | 1893 | 1 |

Warsaw, Ind. | 3514 | 1896 | 0.5 |

Asbury Park, N. J. | 3500 | | 2 |

Keyport, N. J. | 3411 | 1895 | 0.5 |

Deseronto, Ont. | 3338 | 1896 | 0.5 |

Milledgeville, Ga. | 3322 | 1893 | 0.5 |

Carlinville, Ill. | 3293 | | 0.1 |

Gettysburg, Pa. | 3221 | 1894 | 0.3 |

Independence, Kan. | 3127 | 1891 | 0.75 |

LaGrange, Ga. | 3090 | 1893 | 0.25 |

Paola, Kan. | 2943 | 1887 | 0.25 |

Benwood, W. Va.[60] | 2934 | 1899 | 1 |

Gadsden, Ala. | 2901 | 1887 | 1.325 |

Lamar, Mo. | 2860 | 1891 | 0.25 |

Longueuil, Que. | 2757 | 1895 | 0.4 |

Washington, Mo. | 2725 | 1888 | 0.2 |

Renfrew, Ont. | 2611 | 1897 | 0.432 |

Oswego, Kan. | 2574 | 1893 | 0.5 |

Holden, Mo. | 2520 | 1893 | 0.2 |

Burlington, Kan. | 2239 | | 0.5 |

Council Grove, Kan. | 2211 | 1898 | 0.5 |

Wakefield, R. I.[61] | 2170 | | 0.15 |

Catonsville, Md. | 2115 | 1890 | 0.25 |

Attica, N. Y. | 1994 | 1896 | 0.4 |

Hightstown, N. J. | 1875 | 1899 | 0.25 |

No. Berwick, Me. | 1803 | 1896 | 0.3 |

Dunnville, Ont. | 1776 | 1899 | 0.5 |

Rogers Park, Ill. | 1708 | 1889 | 0.4 |

Eatonton, Ga. | 1682 | 1897 | 0.5 |

Caldwell, Kan. | 1642 | 1890 | 0.5 |

LaGrange, Tex. | 1626 | 1891 | 0.25 |

Richfield Springs, N. Y. | 1623 | 1889 | 0.35 |

Valatie, N. Y. | 1437 | 1894 | 0.15 |

Tunkhannock, Pa. | 1253 | | 0.1 |

Mechanics Falls, Me. | 1030 | 1898 | 0.72 |

New Bethlehem, Pa. | 1026 | 1899 | 0.1 |

Fairmount, W. Va. | 1023 | 1898 | 1 |

Atlantic Highlands, N. J. | 945 | | 0.3 |

Rumford Falls, Me. | 898 | 1897 | 0.5 |

Lakewood, N. J. | 730 | 1889 | 0.5 |

Veazie, Me. | 650 | 1889 | 1 |

Portersville, Cal. | 606 | 1890 | 0.151 |

Holmesburg, Pa. | | 1896 | 1 |

Pickering Creek, Pa. | | 1896 | 0.75 |

Overbrook, Penna. | | 1895 | 0.25 |

Vandergrift, Pa. | | 1897 | 0.5 |

Frazerville, P. Q.[62] | | 1899 | 0.2 |

Arnate, Pa. | | 1899 | 0.12 |

Chihuahua, Mex.[62] | | 1899 | 1 |

West Reading, Pa. | | | |

+-----------+ +-----------+

Totals | 1,565,881 | | 252 |

--------------------------+-----------+----------+-----------+

--------------------------+------------+--------+---------------------

| Average | |

|Consumption,|Area of |

Place. | Million |Filters,| Filter

| Gallons: |Sq. Ft. | System.

|Water Works | 1899. |

| Manual. | |

--------------------------+------------+--------+---------------------

Denver, Col. | | 2260 | Special.

Atlanta, Ga. | 4.54 | 2056 | N. Y. P.

St. Joseph, Mo. | | 3842 | J. G.

Oakland, Cal. | 10 | 1960 | N. Y. P.

Kansas City, Kan. | 2 | 2260 | J. G.

Wilkesbarre, Pa.[55] | | 3166 | J. G.

Norfolk, Va. | 3.5 | 2112 | J. G.

Augusta, Ga. | 3.8 | 2112 | N. Y. G.

Quincy. Ill. | 1.2 | 1582 | J. G.

Dubuque, Iowa[56] | | 880 | J. G.

Terre Haute, Ind. | 3 { | 1076 | N. Y. P.

| { | 226 | J. G.

Elmira, N. Y. | 3 | 2034 | J. G.

Chattanooga, Tenn. | | 2080 | J. & N. Y. P.

Davenport, Iowa | 3 | 2380 | Am. P.

Little Rock, Ark. | | 1544 | Am., J., & N. Y. P.

Winnipeg, Mann. | | 390 | N. Y. P.

Oshkosh, Wis. | 2.1 | 550 | W. G.

Macon, Ga. | 1.65 | 1437 | J., W., & N. Y.

Burlington, Ia. | | 1243 | J. G.

Knoxville, Tenn. | 1.93 | 1404 | W. G.

Lexington, Ky. | 1.2 | 678 | J. G.

Kingston, N. Y. | 1.5 | 1120 | N. Y. P.

York, Penna. | 2.37 | 1408 | J. G.

Biddeford, Maine | 2 | 780 | W. G.

Newport, R. I. | 2.1 | | Special.

Bangor, Maine | 3 | 1404 | W. G.

Cedar Rapids, Ia. | 2 | 905 | J. G.

Elgin, Ill. | 1 | 780 | Am. P.

Decatur, Ill. | 2 | 1008 | W. G.

Belleville, Ill. | 0.6 | 339 | J. G.

Columbia, S. C. | | 678 | J. G.

Keokuk, Ia. | | 980 | N. Y. P.

Ottumwa, Ia. | 1.2 | 678 | J. G.

Rock Island, Ill.[55] | 3.5 | 452 | J. G.

Raleigh, N. C. | 1 | 296 | N. Y. P.

Shreveport, La. | | 312 | N. Y. P.

New Castle, Penna | 2 | 1408 | N. Y. G.

Charlotte, N. C. | 0.5 | 530 | N. Y. G.

Nebraska City, Neb. | 0.7 | 116 | N. Y. P.

Streator, Ill. | 1.3 | 100 | Western & Am. P.

Hornelsville, N. Y.[58] | | 700 | N. Y. P.

Augusta, Maine | 1.6 | 100 | W.

St. Thomas, Ont. | 0.6 | 700 | N. Y. P.

Cairo, Ill. | 2.5 | 197 | N. Y. P.

Alton, Ill. | 1 | 1056 | N. Y. G.

Asheville, N. C. | 0.35 | 312 | N. Y. P.

Greenwich, Conn. | 0.4 | 592 | N. Y. P.

Huntington, W. Va. | | 704 | N. Y. G.

Beaver Falls, Pa. | 4.5 | | N. Y.

Champaign, Ill.[57] | 0.75 | | N. Y.

Chatham, Ont. | 0.4 | 280 | N. Y. P.

Adrian, Mich. | 0.45 | 565 | J. G.

Athens, Ga. | 0.45 | 420 | W. G.

East Providence, R. I. | | 176 | J. G.

Winston, N. C. | 0.3 | 156 | W. G.

Danville, Penna. | 1 | 226 | J. G.

Clarksville, Tenn.[58] | 0.5 | 704 | J. G.

Stevens Point, Wis. | 0.25 | 156 | N. Y. P.

Carlisle, Pa. | | 339 | J. G.

Calais, Me. | 0.85 | 275 | W. G.

Long Branch, N. J. | 1.3 | 904 | N. Y. P.

Creston, Ia. | 0.3 | 150 | J.

St. Hyacinthe, Que. | 0.84 | 294 | J. P.

Rome, Ga.[58] | 1.3 | 528 | J. G.

Westerly, R. I. | 0.375 | 396 | N. Y. G.

Merrill, Wis. | | 339 | J. G.

Dennison, Ohio[58] | 1 | 528 | J. G.

Parsons, Kan. | 0.6 | 452 | J. G.

Waterloo, Iowa | 0.7 | 565 | J. G.

Somerville, N. J. | 0.75 | 552 | N. Y. P.

Athol, Mass. | 0.5 | 350 | N. Y. P.

Owego, N. Y. | 0.75 | 234 | N. Y. P.

Brunswick, Maine | 0.33 | 100 | W.

Bucyrus, Ohio | 0.55 | 156 | N. Y. P.

Warren, Ohio | 1.5 | 462 | W. G.

Hopkinsville, Ky. | 0.15 | 140 | N. Y. P.

Brainerd, Minn. | | 156 | N. Y. P.

New Brighton, Pa. | | 156 | N. Y. P.

Niagara Falls, N. Y. | 2.62 | 1019 | J. G.

Durham, N. C. | 0.7 | 252 | W. G.

Winfield, Kan. | | 336 | W. G.

Louisiana, Mo. | | 242 | N. Y. P. & G.

Trenton, Mo. | | 128 | N. Y. P.

Lorain, Ohio | 1.5 | 1356 | J. G.

Sidney, Ohio[59] | 0.5 | | N. Y.

Mexico, Mo. | 0.4 | 66 | N. Y. P.

Mt. Clemens, Mich. | 0.6 | 251 | N. Y. P.

Riverside, Cal. | | 20 | N. Y. P.

Columbus, Miss.[60] | 0.175 | 176 | J. G.

Winchester, Ky. | 0.107 | 152 | J. P.

Salisbury, N. C. | 0.35 | 156 | N. Y. P.

Eufaula, Ala. | | 140 | N. Y. P.

Greenville, Tex. | 0.175 | 156 | N. Y. P.

Exeter, N. H. | 0.179 | 34 | N. Y. P.

Bordentown, N. J. | 0.5 | 156 | N. Y. P.

Lake Forest, Ill. | | 168 | J. P.

Henderson, N. C. | | 118 | W. G.

Reading, Mass. | 0.198 | 336 | W. G.

Goldsboro, N. C. | 0.1 | 156 | W. G.

Rich Hill, Mo. | 0.24 | 140 | N. Y. P.

Mt. Pleasant, Ia. | | 156 | N. Y. P.

Murphysboro, Ill. | | 60 | N. Y. P.

Brandon, Manitoba | 0.36 | 240 | N. Y. P.

Danville, Ky. | 0.1 | 140 | N. Y. P.

Royersford, Pa. | 0.08 | 226 | J. G.

Warsaw, Ind. | 0.5 | 156 | N. Y. P.

Asbury Park, N. J. | 0.5 | 670 | C.

Keyport, N. J. | 0.06 | 156 | W. G.

Deseronto, Ont. | 0.84 | 147 | J. P.

Milledgeville, Ga. | | 156 | N. Y. P.

Carlinville, Ill. | | 38 | Am. or Jackson.

Gettysburg, Pa. | 0.075 | 78 | W. G.

Independence, Kan. | 0.25 | 129 | Am. P.

LaGrange, Ga. | | 34 | N. Y. P.

Paola, Kan. | 0.45 | 66 | N. Y. P.

Benwood, W. Va.[60] | | 306 | J. G.

Gadsden, Ala. | | 430 | N. Y. P. & G.

Lamar, Mo. | | 78 | N. Y. P.

Longueuil, Que. | 0.3 | 100 | N. Y. P.

Washington, Mo. | 0.075 | 50 | N. Y. P.

Renfrew, Ont. | | 100 | N. Y. P.

Oswego, Kan. | 0.3 | 140 | N. Y. P.

Holden, Mo. | 0.05 | 100 | N. Y. P.

Burlington, Kan. | | 79 | J.

Council Grove, Kan. | 0.08 | 78 | N. Y.

Wakefield, R. I.[61] | 0.25 | | N. Y.

Catonsville, Md. | | 78 | N. Y. P.

Attica, N. Y. | | 100 | N. Y. P.

Hightstown, N. J. | 0.025 | 78 | N. Y. G.

No. Berwick, Me. | | 78 | W. G.

Dunnville, Ont. | | 140 | N. Y. P.

Rogers Park, Ill. | 0.35 | 100 | N. Y. P.

Eatonton, Ga. | | 132 | N. Y. G.

Caldwell, Kan. | | 156 | N. Y. P.

LaGrange, Tex. | | 34 | N. Y. P.

Richfield Springs, N. Y. | | 100 | N. Y. P.

Valatie, N. Y. | | 50 | N. Y.

Tunkhannock, Pa. | | | N. Y.

Mechanics Falls, Me. | | 176 | W. G.

New Bethlehem, Pa. | | 50 | J. G.

Fairmount, W. Va. | | 280 | N. Y. P.

Atlantic Highlands, N. J. | 0.109 | 130 | C.

Rumford Falls, Me. | | 113 | W. G.

Lakewood, N. J. | | 156 | N. Y. P.

Veazie, Me. | 0.1 | 176 | W. G.

Portersville, Cal. | 0.060 | 34 | N. Y. P.

Holmesburg, Pa. | 0.046 | 280 | N. Y. P.

Pickering Creek, Pa. | | 234 | W. G.

Overbrook, Penna. | | 78 | W. G.

Vandergrift, Pa. | | 156 | W. G.

Frazerville, P. Q.[62] | | 78 | N. Y. G.

Arnate, Pa. | | 50 | N. Y. G.

Chihuahua, Mex.[62] | | 612 | J. G.

West Reading, Pa. | 0.07 | | W. G.

+------------+--------+

Totals | 108 |77,806 |

--------------------------+------------+--------+---------------------

Special filters, neither sand nor mechanical: Wilmington, Del.; Pop.,

61,431; area, 10,000 sq. ft.; nominal capacity, 10 million gallons. See

Eng. News, Vol. 40, p. 146.

NOTES REGARDING SAND FILTERS IN THE UNITED STATES.

POUGHKEEPSIE, N. Y. Designed by James P. Kirkwood, built in 1872, was

the earliest of its kind in the United States. It was enlarged by the

Superintendent, Charles E. Fowler, in 1896. The walls of the original

filters were of rubble, and in course of time developed cracks and

leaked badly. The walls of the new filter are of rubble, faced with

vitrified brick. The filters treat the water of the Hudson River, which

is sewage-polluted and more or less muddy. Description: Jour. N. E.

Water Works Assoc., Vol. 12, p. 209.

HUDSON, N. Y. Designed by James P. Kirkwood, built in 1874. enlarged in

1888. The filters are open and are used for treating the Hudson River

water, which is sewage-polluted and more or less muddy. Description:

Eng. News, Vol. 31, p. 487.

ST. JOHNSBURY, VT. (E. & T. Fairbanks & Co.) These filters were built

about 30 years ago, and have been recently enlarged. The filters were

originally open, but were afterwards covered with a roof. The single

roof proved inadequate to keep them from freezing, and a second roof

was added inside and under the main roof. They are used for filtering

pond water, which is quite clear and not subject to much pollution. The

water supply is one of two, the other is the town supply and is taken

from the Passumpsic River. No published description.

NANTUCKET, MASS. Designed by J. B. Rider, built in 1892. This filter

is used to remove organisms from the reservoir water supply. It is

only used when the organisms are troublesome, and is satisfactory in

preventing the tastes and odors which formerly resulted from their

presence. Description: Jour. N. E. Water Works Assoc., Vol. 8, p. 171;

Eng. News, Vol. 31, p. 336.

LAWRENCE, MASS. Designed by Hiram F. Mills, built in 1892-3, and put

in operation September, 1893. It is used for treating the water of the

Merrimac River, which contains a large amount of sewage. Description:

Report of the Mass. State Board of Health, 1893, p. 543; Jour. N. E.

Water Works Assoc., Vol. 9, p. 44; Eng. News, Vol. 30, p. 97.

ILION, N. Y. Designed by the Stanwix Engineering Company and are used

for treating reservoir water, which is generally clear and not subject

to pollution. Description: Eng. News, Vol. 31, p. 466.

MOUNT VERNON, N. Y. (New York Suburban Water Company.) Designed by

J. N. Chester, built in 1894. These filters are similar in general

construction to the Lawrence filter, although the dimensions both

vertical and horizontal are reduced, and the area is divided into three

parts. The filters are used for treating reservoir water, which is

generally quite clear, but which is polluted by a considerable amount

of sewage. Since the use of filters the reduction in the typhoid fever

death-rate has been very great. Description: Eng. News, Vol. 32, p. 155.

MILFORD, MASS. Designed by F. L. Northrop. This filter is very simple

in construction, and is used for filtering Charles River water as an

auxiliary supply. Description: Jour. N. E. Water Works Assoc., Vol. 10,

p. 262.

GRAND FORKS, N. D. Designed by W. S. Russell. These filters are covered

with roofs. They treat the water from the Red River, which is very

muddy, and also sewage-polluted, and which formerly caused typhoid

fever. Description: Eng. News, Vol. 33, p. 341.

ASHLAND, WIS. Designed by William Wheeler, built in 1895. The Ashland

filters were the first vaulted masonry filters to be constructed in

the United States, and are used for treating the bay water, which

is polluted with sewage, and is at times muddy from the river water

discharging into the bay near the intake. The filters are below the bay

level, and receive water from it by gravity. Description: Jour. N. E.

Water Works Assoc., Vol. 11, p. 301; Eng. News, Vol. 38, p. 338.

LAMBERTVILLE, N. J. Designed by Churchill Hungerford, and built in

1896. These are open filters with earth embankments, for filtration of

reservoir water. Description: Eng. News, Vol. 36, p. 4.

FAR ROCKAWAY, L. I. (Queens County Water Company.) Designed by Charles

R. Bettes, Engineer in Charge; Charles B. Brush & Co., Chief Engineers;

and Allen Hazen, Consulting Engineer. Constructed in 1896. These

masonry filters were used for the removal of iron from well waters.

They are also designed to be suitable for the filtration of certain

brook waters which are available as auxiliary supplies, but the brook

water has been but rarely used. Description: Eng. Record, Vol. 40, p.

412.

RED BANK, N. J. (Rumson Improvement Company.) Designed by Allen Hazen,

built in 1897. They are similar in construction to the Far Rockaway

filters, and are used for iron removal only. Description: Eng. Record,

Vol. 40, p. 412.

HAMILTON, N. Y. Designed by the Stanwix Engineering Company, and were

built in 1895 to filter lake water. Description: Eng. News, Vol. 39, p.

254.

LITTLE FALLS, N. Y. Designed by Stephen E. Babcock. These filters are

open, and were built in 1898, and are used for filtering river water.

Description: Eng. Record, Vol. 38, p. 7.

SOMERSWORTH, N. H. Designed by William Wheeler. These were the second

vaulted filters to be built in the United States. The supply is from

the Salmon Falls River and flows to the filters by gravity, the filters

being below the river level. Description: Eng. News, Vol 40, p. 358;

Eng. Record, Vol. 38, p. 270.

BERWYN, PENNA. Designed by J. W. Ledoux. These open filters are used

for filtering creek water. Description: Eng. News, Vol. 41, p. 150.

HARRISBURG, PENNA. (State Lunatic Hospital.) Designed by Allen Hazen;

open masonry filters, used for treating the water from a small creek

which is often muddy and is subject to pollution. No published

description.

ALBANY, N. Y. Designed by Allen Hazen. Constructed 1898-99. This

was the third and is the largest vaulted masonry filter plant yet

constructed in the United States. It is used for filtering the Hudson

River water, which is slightly muddy and much polluted by sewage.

Description: Eng. News, Vol. 39, p. 91; Vol. 40, p. 254.

ROCK ISLAND, ILL. Designed by Jacob A. Harman. Open filters with

embankments, used for filtering the Mississippi River water, which is

very muddy and also polluted by sewage. No published description.

* * * * *

CAPACITY OF FILTERS.

Estimating the total additional area of sand filters for which figures

are not available at 100 acres, and the maximum capacity of sand

filters at three million gallons per acre daily, and of mechanical

filters at three million gallons per thousand square feet of filtering

area, the total filtering capacity of all the filters in the world used

for public water supplies in 1899 is nearly 1600 million gallons daily,

of which 15 per cent is represented by mechanical filters and 85 per

cent by sand filters. In the United States, including Wilmington, the

total filtering capacity is nearly 300 million gallons daily, of which

18 per cent is represented by sand filters, 79 per cent by mechanical

filters, and 3 per cent by a special type of filters.

APPENDIX V.

LONDON’S WATER-SUPPLY.

London alone among great capitals is supplied with water by private

companies. They are, however, under government supervision, and

the rates charged for water are regulated by law. There are eight

companies, each of which supplies its own separate district, so that

there is no competition whatever. One of the companies supplying

460,000 people uses only ground-water drawn from deep wells in the

chalk, but the other seven companies depend mainly upon the rivers

Thames and Lea for their water. All water so drawn is filtered, and

must be satisfactory to the water examiner, who is required to inspect

the water supplied by each company at frequent intervals, and the

results of the examinations are published each month.

In 1893 the average daily supply was 235,000,000 gallons, of which

about 40,000,000 were drawn from the chalk, 125,000,000 from the

Thames, and 70,000,000 from the Lea. Formerly some of the water

companies drew water from the Thames within the city where it was

grossly polluted, and the plagues and cholera which formerly ravaged

London were in part due to this fact. These intakes were abandoned

many years ago, and all the companies now draw their water from points

outside of the city and its immediate suburbs.

The area of the watershed of the Thames above the intakes of the water

companies is 3548 square miles, and the population living upon it in

1891 was 1,056,415. The Thames Conservancy Board has control of the

main river for its whole length, and of all tributaries within ten

miles in a straight line of the main river, but has no jurisdiction

over the more remote feeders. The area drained is essentially

agricultural, with but little manufacturing, and there are but few

large towns. In the area coming under the conservators there are but

six towns with populations above 10,000 and an aggregate population

of 170,000, and there are but two or three other large towns on the

remaining area more than ten miles from the river. These principal

towns are as follows:

Town. Population 1891. Distance above

Water Intakes.

Reading 60,054 49 miles

Oxford 45,791 87 miles

New Swindon 27,295 116 miles

High Wycomb 13,435 33 miles

Windsor 12,327 18 miles

Maidenhead 10,607 25 miles

Guildford 14,319 20 miles

Guildford is outside of the conservators’ area. All of the above towns

treat their sewage by irrigation.

Among the places that are regarded as the most dangerous are Chertsey

and Staines, with populations of 9215 and 5060, only 8 and 11 miles

above the intakes respectively. These towns are only partially sewered

and still depend mainly on cesspools. An attempt is made to treat the

little sewage which they produce upon land, but the work has not as yet

been systematically carried out. There are also several small towns of

3000 inhabitants or less upon the upper river which do not treat their

sewage so far as they have any, but, owing to their great distance,

the danger from them is much less than from Chertsey and Staines.

Twenty-one of the principal towns upon the watershed have sewage farms,

and there are no chemical precipitation plants now in use.

Boats upon the river are not allowed to drain into it, but are

compelled to provide receptacles for their sewage, and facilities

are provided for removing and disposing of it; and as an additional

precaution no boat is allowed to anchor within five miles of the

intakes.

The conservators of the river Lea have control of its entire drainage

area, which is about 460 square miles, measured from the East London

water intakes, and has a population of 189,287. On this watershed there

is but a single town with more than 10,000 inhabitants, this being

Lutton near the headwaters of the river, with a population of 30,005.

The sewage from Lutton and from seventeen smaller places is treated

upon land. No crude sewage is known to be ordinarily discharged into

the river. At Hereford, eleven miles above the East London intakes,

there is a chemical precipitation plant. The conservators do not

regard this treatment as satisfactory, and have recently conducted

an expensive lawsuit against the local authorities to compel them to

further treat their effluent. The suit was lost, the court holding that

no actual injury to health had been shown. It is especially interesting

to note that of the thirty-nine places on the Thames and the Lea giving

their sewage systematic treatment there is but a single place using

chemical precipitation, and there it is not considered satisfactory.

Formerly quite a number of these towns used other processes than land

treatment, but in every case but Hereford land treatment has been

substituted.

In regard to the efficiency of the sewage farms, it is believed that

in ordinary weather the whole of the sewage percolates through the

land, and the inspectors of the Conservancy Boards strongly object to

its being allowed to pass over the surface into the streams. The land,

however, is for the most part impervious, as compared to Massachusetts

and German sewage farms, and in times of heavy storms the land often

has all the water it can take without receiving even the ordinary flow

of sewage, and much less the increased storm-flow. At such times the

sewage either does go over the surface, or perhaps more frequently

is discharged directly into the rivers without even a pretence of

treatment. The conservators apparently regard this as an unavoidable

evil and do not vigorously oppose it. It is the theory that, owing

to the increased dilution with the storm-flows, the matter is

comparatively harmless, although it would seem that the reduced time

required for it to reach the water-works intakes might largely offset

the effect of increased dilution.