SYSTEM OF SUPPLY.
The systems of supply may be arranged under three general heads, viz:
1st. By springs and wells.
2d. By gravitation.
3d. By pumping.
SPRINGS AND WELLS.
We have, under this name, nature’s resources for supplying our wants,
whose facilities for furnishing the requisite supply depend upon
the local rain-fall, configuration of the land, and the nature, or
geological formation, of surface and subsoils.
Land springs are fed by rain-water, gravitating through loose
permeable soils. The waters are very readily affected by infiltration
of surrounding soils, and their course so easily changed in any
direction that the permanence of such a source can not be relied upon.
Deep springs are fed by the waters falling upon and soaking down to
great depths, and find their way to the surface through some fault,
upheaval or other great geological disturbance, or between some
impermeable strata. The most copious springs are in the tertiary
strata, and the law, as regards their abundance, is “the rarer the
visible springs may be, the more copious they would be found.” The
permanence of the springs can only be relied upon after careful
gauging, extending over several years.
Wells may be separated under the following divisions:
Shallow, or dug wells.
Ordinary deep, or pump wells.
Artesian wells.
“Shallow and deep wells are those which are sunk through a
permeable stratum, and form, as it were, reservoirs, into which
the land springs may filter and accumulate; whilst artesian wells
are those which are sunk through an impervious upper stratum, to
reach a subterranean water-bearing stratum lying, in its turn, upon
an impervious upholding bed. In the former cases, the quantity of
water obtainable is simply that which can filter through the sides
of the well to replace the water removed, or which may accumulate
in any reservoir formed below; whilst, in the latter case, the
quantity obtainable will depend simply upon the power of the
water-bearing stratum to transmit water.
“In the case of deep-seated wells, the probable yield of water
must depend, primarily, upon the area of permeable strata likely
to affect the supply, and upon the facilities those strata may
offer for the passage of water; and, secondly, upon the rate of
consumption which takes place in the neighborhood, for the quantity
of water which any particular stratum can supply is only a limited
quantity; so that, evidently, if the water be taken at one point,
no more will remain for the other.”--(Hydraulic Engineering,
Weale’s Series.)
The above fact is illustrated, practically, in London, where the
water line of the chalk formation has been permanently lowered to
the extent of fifty or sixty feet below Trinity high-water mark;
and it is even stated that the level of the water in the wells,
near the summit of this formation, rises, on the Monday morning, in
consequence of the cessation of pumping in London during the Sundays.
The experience of Liverpool corroborates this fact: that the Windsor
well, having a depth of 210 feet, affected the surrounding wells
to a maximum distance of a mile and three quarters. The celebrated
engineer and originator of the well system of Liverpool, Robert
Stephenson, from long experience and careful observation, offered the
following conclusions (from Hughes water-works):
“That an abundance of water is stored up in the new red sandstone,
and may be obtained, by sinking shafts and driving tunnels, about
the level of low water.
“That the sandstone is generally very pervious, admitting of deep
wells drawing their supply from distances exceeding one mile.
“That the permeability of the sandstone is occasionally interfered
with by faults or fissures filled with argillaceous matter,
sometimes rendering them partially, or wholly, water-tight.
“That neither by sinking, tunneling, nor boring, can the yield of
any well be very materially and permanently increased, except so
far as the contributing area may be thereby enlarged.
“That the contributing area to any given well is limited by the
amount of friction experienced by the movement of the water through
the fissures and pores of the sandstone; and
“That there is little or no probability of obtaining, permanently,
more than about 1,000,000 or 1,200,000 gallons a day from each
well, and this only when not interfered with by other deep wells.”
Statistics of the flow of the Windsor well show that the yield, in
1843, was 1,152,000 gallons per day; in May, 1848, 807,061 gallons;
in January, 1850, from 705,667 to 634,752 gallons. The observations
of the Green Lane well, in the same city, give the decrease in flow,
per annum, at 4.7 to 6 per cent.
A plan has been proposed, by Mr. Bailey Denton, that, in order to
increase the water-bearing stratum under London, sufficiently for
a water supply, and also secure the well-known benefits of the
filtration powers of the chalk, to let the Thames water pass down to
the chalk, through the London clay, by means of wells sunk or bored.
The objections raised against this plan is the possibility of the
wells becoming choked by accumulation of impurities.
Mr. J. T. Fanning in his valuable “Treatise on Water Supply
Engineering,” says:
“The success of wells, penetrating deep into large subterranean
basins, upon the first completion, has usually led to their
duplication at other points within the same basin, and the flow of
the first has often been materially checked upon the commencement
of flow in the second, and both again upon the commencement of
flow in a third, though neither was within one mile of either of
the others. The flow of the famous well at Grenelle was seriously
checked by the opening of another well at more than three thousand
yards, or nearly two miles distant.”
POLLUTION OF WELL WATER.
It is stated that about fifteen millions of the British population
live in towns and urban districts. Even if we assume, which is not
yet the case, that all these people are supplied by water-works, the
remaining twelve millions of county population derive their water
almost exclusively from shallow wells, and these are, so far as our
experience extends, almost always horribly polluted by sewage and by
animal matter of the most disgusting origin.
As the contents of the water-hole or well are pumped out, they are
immediately replenished from the surrounding disgusting mixture, and
it is not therefore very surprising to be assured that such wells
do not become dry even in summer. Unfortunately, excrementitious
liquids, especially after they have soaked through a few feet of
porous soil, do not impair the palatability of water; and this
polluted liquid is consumed from year to year without a suspicion of
its character.
Our acquaintance with a very large portion of this class of potable
waters, has been in consequence of the occurrence of severe outbreaks
of typhoid fever amongst consumers of this character of water.
“The samples of water from deep unpolluted wells were obtained
from wells or bore-holes of a depth rarely less than 100 feet,
and reaching in one case 1,285 feet. In many cases these wells
were partly or wholly supplied by surface-polluted water. Such
water, when it penetrates only to shallow wells still retains a
considerable proportion of its polluting organic matter in an
unoxidized condition: but when it descends through one hundred
feet or upwards of porous soil or rock, the exhausted filtration
to which it has been subjected in passing downwards through so
great a thickness of material, and the rapid oxidation of the
dissolved organic matters in a porous and aerated medium, afford
a considerable guarantee that all noxious constituents have been
removed.”--(Rivers Pollution Commission, 1874.)
“Deep wells may become polluted, either by admission of soakage
from the superficial strata into the shaft of the well, or by
access of polluted water through open fissures in the rock in which
the well is sunk.”--(Rivers Pollution Commission, 1874.)
“Even where wells are sunk to great distance (one was sunk at
Bondy, near Paris, to a depth of 247 feet), the surrounding soil is
not free from danger of pollution by the soaking of the foul liquid
into the side of the well.”--(Fifth report Massachusetts State
Board of Health.)
The following table shows the average analysis of ten worst examples
of well water (parts in 100,000 parts):
AV. CARBON NITROGEN
DEPTH. ORGANIC. ORGANIC. CHLORINE. HARDNESS.
Shallow wells, -- 1.560 .241 16.56 63.24
Deep wells polluted, -- .363 .092 9.45 36.27
Deep wells unpolluted, 380 .151 .032 14.14 27.4
ARTESIAN WELLS.
Artesian is the name applied to water-springs rising above the
surface of the ground by natural hydrostatic pressure, or boring a
small hole down through a series of strata to a water-bearing bed
inclosed between two layers. It was first practiced in 1100, in
province of Artois, France, whence it derives its name.
“The second and tertiary geological formations, such as those
underneath London and Paris, often present the appearance of
immense basins; the boundary or rim of the basin having been formed
by an upheaval of the subjacent strata. In these formations it
often happens that a porous stratum, consisting of sand, sandstone,
chalk, and other calcareous matter, is included between two
impermeable layers of clay, so as to form a flat, porous ‘U’ tube,
continuous from side to side of the valley, the outcrop on the
surrounding hills forming the mouth of the tube. The rain filtering
down the porous layer to the bottom of the basin, forms there a
subterranean pore, which, with the liquid or semi-liquid column
pressing upon it, constitutes a sort of huge natural hydrostatic
bellows; sometimes the pressure on the superincumbent crust is so
great as to cause an upheaval or disturbance of the valley, and
there can be little doubt that many earthquakes that are manifestly
not of volcanic origin, are due to this simple cause.”--(Ninth
edition Encyclopedia Britannica.)
“An overflow results only when the surface that supplies the
water-bearing stratum is at an elevation superior to the surface
of the ground where the well is located, and the water-bearing
stratum is confined between impervious strata. In such cases the
hydrostatic pressure from the higher source forces the water up to
the mouth of the bore.”--(Fanning Water Supply.)
“In the tertiary formations the porous layers are not so thick as
in the secondary, and, consequently, the occurrence of underground
lakes is not on so grand a scale; but there being more frequent
attenuation of these sandy beds, we find a greater number of them,
and often a series of natural fountains may be obtained in the same
valley preceding from water-bearing strata at different depths, and
rising to different heights.
“It does not follow that all the essentials for an Artesian well
are present, though two impermeable strata, with a porous one
between, may crop out around a basin. There must be, in the first
place, continuity of the permeable bed for the uninterrupted
passage of the water, and there must be, on the other hand, no flaw
or breach in either of the confining layers by which the water
might escape. To one or the other of the causes is due the failure
of many attempts to find Artesian wells, where, from appearances,
they might be expected. It has occasionally happened that on
deepening the bore, with the hope of increasing the flow of water,
it has ceased altogether, doubtless from the lower confining layer
being pierced, and the water allowed to escape by another outlet.
“The subterranean bore is frequently of small extent, and of the
nature of a channel rather than of a broad sheet of water; and the
existence of one spring is no guarantee that another will be found
by merely boring to the same depth in the neighborhood.
“The preliminary theoretical determination of the existence of
these Artesian conditions is in itself a difficult matter, and can
be arrived at only by a thorough acquaintance with the geological
disposition of the district.”--(Ninth edition Encyclopedia
Britannica.)
“The question of a supply of water from deep wells, made by
boring, and commonly called artesian, has been somewhat discussed
in Philadelphia, but there is no probability that an adequate
supply, for the general use of the city could be obtained in that
manner; and the quality of the water obtained from such wells
varies very much in different localities, depending upon the
nature of the strata from which the water is procured, and this
Commission can not recommend any dependence upon such plans for
the general city supply, attended, as they are, with great expense
and extreme uncertainty, and being, in every case, more or less
experimental.”--(Philadelphia Water Supply Commission of Engineers,
1875.)
The flowing water of the Kissingen spring, Bavaria, is produced by
carbonic acid gas.
TEMPERATURE OF WELLS.
Invariably the temperature of water from great depths is higher than
at the surface, this being due to some unknown source of heat in the
interior of the globe.
In Scotland, the rate of increase of temperature, after permanent
degree has been attained, is about one degree Fahrenheit for every
forty-eight feet of descent.
At Grenelle, the temperature was found to be 1.8 degrees for every
106 feet of descent below the point of constant temperature.
The average rate of increase of temperature is one degree for a
descent of from forty to fifty feet.
The temperature of the boring at Columbus increased, below the
permanent line, one degree in every seventy-one feet.
EXAMPLES OF ARTESIAN WELLS.
The famous well at Grenelle, France, was commenced, by the
government, in 1834, and after repeated failures and discouragements
almost to abandonment, notwithstanding the urgent representations
of the scientist Arago, that water would be found, the end was
accomplished at the depth of 1,798 feet, in the year 1843. The
diameter of the bore is 3½ inches; capacity, 600 gallons per minute;
temperature of water, 82 degrees; height of flow, 128 feet. The
expense attending this boring was 300,000 francs. The Passy well,
near Paris, supplied from the same water-bearing stratum of the
Grenelle, is 1,923 feet deep; 2′ 4″ inches bore at bottom; capacity,
5,582,000 gallons per day; height of flow, 54 feet. The La Chapelle
well was started in 1866, with a gigantic bore of five feet seven
inches, and by November, 1869, had reached a depth of 1,811 feet,
the intention of the engineer being to extend it to a depth of 2,950
feet.
At the part of Paris named Butte-aux-Caelles, a well was started, in
1866, of six and a half feet diameter, to be carried down to a depth
of 2,600 to 2,900 feet.
The Kent Water-Works, of London, is supplied by wells in the chalk
formation, yielding 9,000,000 gallons daily. This great flow is due
to what is known as a fault in the London basin strata.
St. Louis has a well 3,147 feet deep.
Louisville has a three-inch well, 2,086 feet deep, with a capacity
same as the Grenelle well.
There have been nine artesian wells successfully bored in Cincinnati,
a description of which will be found on page 107.
Charleston, South Carolina, has an artesian well 1,970 feet deep,
from which pure soft water, of 90° temperature, flows ninety feet
above the surface. It has five inch tubing on top and two and
three-fourths inch diameter at bottom. The cost was $2,500.00, and
the time required in sinking was a little more than a year. There
is also an artesian well, in the same city, 1,250 feet deep, which
discharges 25,000 gallons a day, of water, at a temperature of
eighty-eight degrees, strongly impregnated with sodium and magnesium.
The desert of Sahara has a number of well borings, some yielding as
high as 1,500,000 gallons daily. The depth varies from 130 to 400
feet, and temperature 70 to 77 degrees.
The Ohio State authorities undertook to supply the capital by an
artesian well. After two failures, in attempting to tube out the
quicksand, they succeeded (in November, 1857) in piercing through
the rock, and at a depth of 149 feet a vein of water was struck that
continued to wash away the borings for nearly 100 feet below. On
the 1st of October, 1870, a depth of 2,775 feet was reached, but no
flowing water obtained, when the undertaking was abandoned for want
of an appropriation.
The record of the boring is tabulated as follows:
---+-------------+------------+------------------------------+----------
| SYSTEM. | GROUP. | STRATA. |THICKNESS.
---+-------------+------------+------------------------------+----------
| | | | FEET.
1 | Drift. | Alluvial | Clay, sand, and gravel. | 123
| | drift. | |
| | | |
| { | Base of | |
2 | Devonian. { | Hamilton. | Dark bituminous shale. | 15
| { | Helderberg.| Dark and gray limestone with |
| | | bands of chert. |
| | | |
| { | Niagara. | Sandy above, darker and | 626
3 | Upper { | | argillaceous below. |
4 | Silurian. { | Clinton. | Red, brown, and gray shales | 162
| { | | and marls. |
| | | |
| { | Hudson | |
5 |Lower { | Trenton. | Greenish calcareous shale. | 1058
6 |Silurian. { |Calciferous.| Light drab sandy magnesian | 475
7 | { | | limestones. |
| { | Potsdam. | White sand-rock, calcareous. | 316
---+-------------+------------+------------------------------+----------
Temperature of well at bottom, 88 degrees, being uniform for 90
feet, at 53 degrees, will make an increase of one degree for every
additional 71 feet. It was the opinion of Prof. Newberry, that, if
water was successfully struck, it would be of a saline character.
Dubuque, Iowa, is supplied by a spring accidentally struck while
tunneling in a neighboring drift.
At the upper basin of the Thames River there are seven springs, whose
capacity is estimated at 32,000,000 gallons daily.
Liverpool, England, has four wells, with a combined capacity of
6,000,000 gallons daily.
Birmingham, England, has four wells, from which the water company
derives 8,000,000 gallons daily.
Washington has over 400 wells, and Cincinnati about 300, nine of
which are artesian, that were bored by private enterprise.
The deepest well in the world is near Berlin--4194 feet deep without
piercing the salt formation.
WELL BORING.
The art of boring into the earth was practiced by the Chinese 2,000
years ago, the feature of their system being the percussive action of
a tool suspended by a flexible rope.
The system now practiced in Great Britain, and on the Continent,
is that in which the tools are attached to rods, consisting of a
number of lengths, from ten to thirty feet long, joined by a separate
collar, with a combined vertical and definite rotary motion, produced
by a swivel joint in the upper length, or by suspending the rod to a
“dog.” An ordinary well is first sunk to such a depth that the water
below will rise, through the boring, into it. The object is to partly
facilitate the object of boring, but chiefly to enable the pumps
to be fixed without too great a length of suction. In deep wells,
windlasses, driven by steam power, are used for operating the tool;
the size of rod being, usually, 1¼ inch square; but for an eight
foot boring, a 4½ inch square rod was used. To reduce the jarring
and vibration, where borings are of considerable depth, the rods are
hollow, in order to give same rigidity and resistance to torsion with
less weight, and made buoyant, when working in water, by filling
the rod with cork or light wood. A sliding joint, known as the
“Oëuyenhausen joint,” is frequently used to bring the jarring only
on that portion of the boring rod below. A shell pump is employed,
in combination with the boring tool, for gathering the detritus,
which obviates frequent raising of rod. Free-falling tools, guided by
sliding joint, with catch or pall to raise same, are largely used.
The weight of tool depends upon the depth and character of boring,
that of the La Chapelle well being four tons.
In the oil-well boring of Pennsylvania, the rope (with about 50 feet
of iron bar, sliding jaws, sinking bar, flat drill and sand pump
attached) are exclusively preferred.
PRACTICAL EXAMPLES OF WELLS AS SOURCES OF SUPPLY ONLY.
Where the surface soil and underlying drift possess sufficient
porous qualities for absorption of a large portion of the rain-fall,
together with the natural benefits of the impervious stratum beneath,
having a proper axis of inclination favorable for conducting the
infiltration of adjoining water-sheds, a large supply of water may
be secured by the construction of dug wells for intercepting the
subterraneous water.
Fanning has computed the following available quantities, under
favorable circumstances, for percolation, from one square mile of
porous gathering area (the mean annual rain being assumed at forty
inches depth).
RATIO OF 1-12 OF VOLUME OF PERCOLATION NO. OF PERSONS IT
MONTH. MEAN ANNUAL RAIN. IN DRY YEARS. WOULD SUPPLY AT FIVE
INCHES. CUBIC FEET. CUBIC FEET DAILY.
January, .737 1,712,198 11,264
February, .796 1,479,878 9,736
March, 1.070 2,237,242 14,719
April, .814 566,861 3,729
May, 1.462 387,974 2,552
June, .964 88,282 581
July, 1.077 51,110 336
August, 1.251 30,202 199
September, 1.015 46,464 305
October, 1.076 989,976 6,572
November, .937 2,176,838 14,321
December, .801 2,604,307 17,133
The city of Brooklyn gathers its supply by intercepting ponds. The
source is the southern slope of Long Island, with a drainage area
of 60.25 square miles. The plain is composed of fine sand, which is
saturated with excellent water, the surface of which rises twelve
feet per mile from the tide level at the shore, and which appears at
the surface of the ground in springs and streams, where depressions
occur in the ground level. The minimum observed flow occurred in
1880, and was equal to 9.4 inches on the water-shed. The available
supply is, at times, quite small.
The city of Lynn uses a driven well partly, of which they say, in
their annual report for 1880:
“The doubtful character of any underground supply of water,
especially when it is drawn from beneath a territory occupied by
a densely settled community, makes frequent examination of its
quality a duty not to be disregarded. We invite attention, however,
to the fact that the chemical examination of the well water has
shown an increasing quantity of foreign matter mingling with it as
pumping proceeded, and that this increase suggests an inflow of
water to the wells from some other source than that from which it
was at first drawn.”
This method of securing water, however, is largely resorted to in the
origin of water-works for small cities.
The Sanitary Engineer (Vol. v, No. 5) refers to a proposed well for
Lincoln, Nebraska, a town of 15,000 inhabitants, that the contractor
proposed to dig for the sum of $10,000. The estimated capacity will
be ten million gallons a day, and the editor of the paper observes:
“If a large well is sunk in a very saturated and porous soil, it
will probably furnish the amount required for the city (one million
gallons) at first, possibly a great deal more. But in five years’
time it is not hazardous to predict that such a well will not yield
enough water for Lincoln. As for furnishing ten million gallons a
day for any length of time, there is no well in the world, which
we know of, of such a capacity, and all experience is against the
probability of such an one being discovered.”
GRAVITATION
is that system of supply where the rain-water drainage of elevated
water-sheds is gathered in natural or artificial storage basins, and
conveyed through conduits by gravitation to the point of supply. The
important points entering into the consideration of this method are:
1. Character of water; present and future contamination.
2. Water-shed; present and future requirements for quantity
and availability, with proper knowledge of the geology of the
surrounding country.
3. Rain-fall, absorption and evaporation.
4. Elevation and distance of source.
5. Route of conduit.
6. Cost of construction.
The practical objections to the system are:
1. Contamination of source by surface drainage of cultivated lands;
pollution of feeding streams, or growth of vegetation.
2. Necessity for large impounding reservoirs for storage of water
during rainy seasons, requiring immense puddled walls, whose
stability is questioned.
3. The uncertainty of dependence on the requisite rain-fall, and
liability of short supply, or a possibility of water-famine.
4. The large expenditure at the outstart for construction of supply
that must be ample for future demands.
Surface waters from calcareous cultivated lands are polluted with but
a moderate amount of organic matter; but, as some of this matter is
almost always of animal origin, they are always undesirable, and may
at any time become dangerous for domestic use.
If necessity compels their use, great care ought to be taken to
secure their efficient filtration before they are delivered to
consumers. This affords some, though by no means complete, protection
from the propagation of zymotic disease through the agency of such
waters.
They are generally very hard, and, unless artificially softened,
occasion a great waste of soap when used for washing. Of all the
waters of this description, those which flow from the surface, or
from the drains of sewage farms, are generally most impure, because
the time during which the foul sewage is exposed to the purifying
action of plant and soil is reduced to a minimum.
Surface water from non-calcareous soil is generally soft but usually
turbid and subject to animal contamination. Such water should always
be carefully filtered.
ANALYSIS OF LAND DRAINAGE WATER FROM SEWAGE FARMS (PARTS BY WEIGHT OF
100,000 PARTS).
================+=======+=======+=======+=========+=========+=========
| | | | |PREVIOUS |
| TOTAL |ORGANIC|ORGANIC|CHLORINE.| SEWAGE |HARDNESS.
|IMPURI-|CARBON.| NITRO-| |OR ANIMAL|
| TIES. | | GEN. | |CONTAMIN-|
| | | | | ATION. |
----------------+-------+-------+-------+---------+---------+---------
Worst Condition.| 94. | 2.160 | .274 | 13.10 | 10.090 | 35.58
Best “ | 24.60 | .108 | .055 | 4.05 | 17.920 | 9.20
Average “ | 64.02 | .982 | .191 | 6.36 | 10.443 | 33.09
================+=======+=======+=======+=========+=========+=========
Much depends upon the knowledge of the climatic influences and
rain-fall, extended, as it should be, through years of observation
in determining the available quantity of water. Engineers, however,
are liable to be too sanguine of the resources from water-sheds, by
assuming, as a general rule, the average, rather than the minimum,
rain-fall.
In 1868 nearly all the cities and towns of England, supplied by
gravitation, suffered a water-famine, because of the overestimate of
the available rain-fall, and in an insufficient provision of storage
for an unusually long drought. Although the rain-fall for the year
was above the average, yet it was unequally distributed.
The authorities of Manchester were obliged to publish official
notices cautioning the inhabitants against waste, and, on the 3d
of August, limited the supply to the city to twelve hours of the
day, stopped the street watering, and diminished the trade supplies
by one-half. In the middle of September the general supply of the
town was further limited to eight hours per day. Many persons were
prosecuted for waste or undue use of water.
Liverpool, Sheffield, Bristol, and several other large cities were
obliged to resort to like severe methods enforced at Manchester. New
York has been using every gallon that the aqueduct is capable of
supplying; and, during the drought of last summer, when the head of
water at Croton Lake was diminished, the capacity of the aqueduct
was so reduced that the flow of water to the city was reduced, and a
water-famine averted only by a Providential rain-fall.
The rule observed among engineers, in Great Britain, in determining
the calculated rain-fall, is the deduction of one-sixth from the
average rain-fall of twenty years for an average annual rain-fall
of the three driest consecutive years in that period. But, as Mr.
Homersham, C. E., observes, the axiom in mechanics, that the strength
of a beam is the strength only of its weakest parts, applies also to
gravitation water-works, their real strength or power of supply being
only the minimum quantity they may be reduced to.
Allowance for absorption depends upon the geological formation and
stratification, and for evaporation, upon local influences.
The following is taken from Hughes’ Water-Works:
“A flat, low-lying country is seldom well adapted for the
impounding of water by embanking across the valleys. In such a
district, long and shallow embankments would be required, and
these would cause the water to spread out over a great area with a
very shallow depth. Under these circumstances, the water is apt to
vegetate and become highly impure. Again, in low-lying districts of
flat countries the rain-fall is seldom nearly so great as in upland
districts, so that much larger drainage areas must be sought.”
In addition to the general configuration of the valleys, which ought
to be deep and with precipitous sides, flanked by lofty hills, there
are several other points which require attentive examination in
projects for collecting water from drainage areas:
1. The area of water-shed.
2. The geological character of the soil as affecting its capacity
to absorb rain, and to allow the infiltration of water through it.
3. The character of the surface soil as affording soluble
ingredients which may be taken up by the water and serve to
contaminate its quality. In this point of view, districts of
decomposing peat, districts of arable agricultural land richly
manured, and places thickly covered with population, are often
highly objectionable.
4. The rain-fall of the district, and especially the minimum fall
in any one year.
5. The nature of the surface-soil as affording facilities for
procuring puddle and constructing retentive reservoirs.
6. The consideration of compensation to mill-owners and possibly to
land-owners where the water is used for irrigation.
The geological structure is extremely important in estimating the
capacity of a drainage area. It is not alone the rain which falls on
the sloping surface of the hills, and finds its way by gravitation
to the lower levels; but the effect of springs is also very great
in augmenting the quantity of water. Many drainage areas are also
valleys of elevation, in which the strata dip in opposite or
anticlinal directions on opposite sides of the valley. In this case
it is evident that much of the rain falling on a porous surface will
insinuate itself between the partings of the strata, and flow off in
a direction contrary to that of the surface drainage.
From Mr. Beardmore’s work we take the following, as the proportion or
percentage of rain-fall which flows off the surface:
“From twenty examples we have 89 as the largest per centage, the
lowest 29 per cent., and the average 64 per cent.
“The Eaton Brook water-shed, in Madison County, New York, of
6,800 acres, with steep slope and compact soil, underlaid by hard
greywacke rock, elevated 1,350 feet above the sea, availed 66 per
cent. of the rain-fall as surface flow.
“A similar water-shed, Madison Brook, gave 50 per cent. Experiments
by Wm. McAlpine, for Albany water-works, shows that from a
water-shed of 2,600 acres, 41½ per cent. of the rain-fall was
carried off by the streams from May till October, inclusive, while
from November till April, 77.6 per cent. was so carried off.”
In England the allowance for absorption and evaporation ranges from
nine to nineteen inches per annum. In this country it is from 75 to
100 per cent. greater.
We produce from “Fanning’s Water Supply” the following table of
experiments on evaporation from surfaces of shallow tanks:
Cambridge--Length of trial, one year; evaporation in inches, 56.00
Salem “ “ “ “ 56.00
Syracuse “ “ “ “ 50.20
Ogdensburgh “ “ “ “ 49.37
Dorset, England “ three years “ “ 25.92
Oxford “ “ five “ “ “ 31.04
Bombay “ five “ “ “ 82.28
Croton average, six, “ mean evap. equal 81 } 39.21
per cent. of rain-fall. }
Lea Bridge, London “ seven “ average rain-fall 27.7
annual evap. min. 12.067
“ “ max. 25.141
The following from the same author of the minimum flow of streams in
cubic feet per second, per each square mile of water-shed:
From 1 square mile .083
From 10 square miles .1
From 25 square miles .11
From 50 square miles .14
From 100 square miles .18
From 250 square miles .25
From 500 square miles .40
From 1,000 square miles .35
From 1,500 square miles .38
From 2,000 square miles .41
From the different surfaces, its ratio of the annual rain, including
floods and flow of springs, is approximately as follows:
PER CENT.
From mountain slopes or steep rocky hills, 80 to 90
From wooded swamp lands, 60 to 80
From undulating pasture and woodland, 50 to 70
From flat cultivated land and prairie, 45 to 60
MONTHLY EVAPORATION FROM RESERVOIR.
(_From Fanning._)
------------------+----+----+----+----+----+-----+
|JAN.|FEB.|MAR.|APR.|MAY.|JUNE.|
------------------+----+----+----+----+----+-----+
Mean ratio--inches|.30 |.35 |.50 |.80 |1.45|1.70 |
==================+====+====+====+====+====+=====+
------------------+-----+----+-----+----+----+----
|JULY.|AUG.|SEPT.|OCT.|NOV.|DEC.
------------------+-----+----+-----+----+----+----
Mean ratio--inches|1.85 |2.00|1.45 |.75 |.50 |.35
==================+=====+====+=====+====+====+====
AVERAGE AVAILABLE RAIN-FALL FOR STORAGE PURPOSES.
(_From Fanning._)
------------------------+----+----+----+------+----+-----+
|JAN.|FEB.|MAR.|APRIL.|MAY.|JUNE.|
+----+----+----+------+----+-----+
Gain by rain--inches |2.00|2.21|2.40| 2.93 |3.47|2.88 |
Loss by evaporation--in.| .60| .70|1.00| 1.60 |2.90|3.40 |
+----+----+----+------+----+-----+
Difference--Gain inches |1.40|1.51|1.40| 1.33 | .57| -- |
Difference--Loss inches | -- | -- | -- | -- | -- | .52 |
========================+====+====+====+======+====+=====+
------------------------+-----+----+-----+----+----+----+------
|JULY.|AUG.|SEPT.|OCT.|NOV.|DEC.|TOTAL.
+-----+----+-----+----+----+----+------
Gain by rain--inches |2.99 |3.00|2.67 |2.53|2.48|2.24| 32.
Loss by evaporation--in.|3.70 |4.00|2.90 |1.50|1.00| .70| 24.
+-----+----+-----+----+----+----+------
Difference--Gain inches | -- | -- | -- |1.03|1.48|1.54| 8.
Difference--Loss inches | .71 | .80| .23 | -- | -- | -- | --
========================+=====+====+=====+====+====+====+======
SUMMARY OF FLOW OF RAIN-FALL IN CU. FT. PER MINUTE PER SQUARE
MILE.--(_From Fanning._)
AT LAKE AT CROTON
COCHITUATE BASIN
CU. FEET. CU FEET.
January, 99.17 92.48
February, 150.42 147.69
March, 174.76 177.02
April, 169.80 132.63
May, 131.80 164.49
June, 44.27 115.12
July, 45.27 48.37
August, 49.15 70.22
September, 42.84 85.99
October, 62.45 81.08
November, 75.90 124.92
December, 78.94 106.23
AQUEDUCTS.
The plan, as adopted by Mr. Hawskley at Liverpool, and Mr. Bateman
at Glasgow, of subterranean pipes, is now universally followed by
engineers. And there is no longer any excuse for incurring the outlay
which must attend the erection of monumental structures, such as were
necessary in the times of the ancient Romans.
The engineer of Marseilles Conduit adopted the “Pont du Gard” plan
for conducting the waters of the Durance, in preference to iron
pipes, and constructed the splendid folly, “as Humber terms it,” of
the aqueduct “Roquefavour.” The dimensions are:
Length, 1,289 feet.
Height, 266 feet.
1st tier of 12 arches each 49½ feet span.
2d tier of 15 arches each 52½ feet span.
Upper tier of 54 arches each 16½ feet span.
The cost was $750,000, while inverted syphon pipes could have been
laid for one-third of this sum.
_The aqueduct for Glasgow_ is thirteen miles in tunnels, 3¾ miles of
iron-piping across valleys, and nine miles of opening cutting and
bridges. There are eighty distinct tunnels, and twenty-five important
iron and masonry aqueducts. On the line is the Drymen bridge on
masonry piers, eighteen feet apart, with two pipes surrounded by wood
lagging, a forty-eight-inch syphon at Aberfoyle Road, and a lofty
bridge at Ballewan, seventy feet in height.
_The Aberdeen water-works_ has a thirty-six-inch syphon, 1,200 feet
in length, across Cullen Burn, supported by granite piers.
The Croton aqueduct is a masonry channel lined with brick. The bottom
is an inverted arch with cord 6.75 feet, and versed sine 0.75 feet;
side walls are 4 feet high, and battered so that at the top they are
7′ 4″ apart, and surmounted with a semi-circular arch. The interior
is 8.64 feet high, and area 53.34 square feet.
The grade is 0.021 feet per 100 feet, total length 38 miles. It
crosses the Manhattan Valley 2 miles in extent, with two 36-inch,
one 48, and one 60-inch cast-iron pipes, and over the Harlem River
by granite bridge, known as High bridge, 100 feet above high water,
composed of seven 50-feet and eight 80-feet spans. The conduit over
the bridge consists of two 36-inch cast-iron pipes, and a wrought
pipe 7 feet 6½ inches in diameter, resting upon saddles, supported by
cast-iron standards placed 12 feet apart between the 36-inch pipes.
_The aqueduct over Cabin John Creek_, of Washington, D. C., water
supply, consists of a single arch of masonry 220 feet span, is the
largest masonry arch in the world. The rise is 57 feet 7 inches,
thickness of crown 4 feet 2 inches, and at spring 6 feet 2 inches.
Water is conveyed in an iron pipe 9 feet in diameter, built in solid
masonry.
The bridge over Georgetown Creek, on line of Washington Conduit,
is 200 feet span with two cords of iron pipe 4 feet in diameter,
1½ inches thickness, used as water conductors. The pipes were
first lined with staves of resinous pine 3 inches thick to prevent
freezing, but have been taken out. No allowance is made for expansion
or contraction. A similar plan is in use at Philadelphia, over the
valley of Wissahikon, consisting of two 20 inch cast-iron flange
pipes serving as top members of a series of inverted bow-string
trusses. There are four spans, each 169 feet 9 inches. Center span
100 feet above ordinary level of the water.
The Boston aqueduct crosses the Charles River by syphon pipes--two,
30 inches, and the other 36 inches in diameter. Starting from a pipe
chamber on the western side of the valley, the pipe descends 52.11
feet below the level of conduit, and rests on a masonry bridge of
three arches.
One of the syphons for supplying Madrid, Spain, crosses a valley
4,560 feet in length, consisting of four lines of cast-iron pipes
three feet in diameter.
Dublin is supplied through 30,336 yards of 33-inch and 8,272 yards
of two lines of 27-inch cast-iron pipes--20,000 yards laid through
private property. The average fall is 20 feet per mile. There are
three relief-tanks on line of 33-inch pipe. The capacity of this pipe
was calculated at sixteen millions per day, while the actual delivery
exceeded twenty millions.
Toronto is supplied by a 4-foot wooden pipe, 7,000 feet in length,
under pressure.
Manchester, N. H., has a wooden penstock, six feet in diameter, 600
feet in length, that conveys supply to water wheels, under a head of
twelve feet at entrance and thirty-eight feet at outlet.
The new conduit for water supply of Baltimore is a continuous
tunnel, seven miles long, running from the dam to the receiving
reservoir--“Lake Montebello.” In its construction no open cuts were
made; all work being done by drifting. Its depth below the surface
of ground varies from 65 to 360 feet. The internal diameter is 12
feet; the fall is one foot per mile; capacity 170 millions daily.
Fifteen shafts were sunk during the constructive work. Two miles of
the tunnel were through material that required to be arched with
brick; the remaining distance was through very hard rock that did not
require arching. The cost of this structure was about two millions of
dollars.
Chicago has two tunnels under Lake Michigan, parallel with each
other, 46 feet apart, extending to a crib, located in the lake, two
miles from the shore. The first one was started, in 1864, under
adverse criticism, and successfully completed in 1867. The cost, with
the crib, was $457,800. It is five feet horizontal diameter, and 5′
2″ vertical diameter, and made of brick. The second one was built in
1872-’74; is five feet in diameter, lined with brick. It extends from
the North Side Works, a further distance of 20,000 feet, under the
city and Chicago River to West Side Works. The cost of this tunnel,
under the river, was $414,000, and under the city $543,000. The
nature of the excavation was generally through stiff blue clay with
occasionally pockets of quicksand.
The Sudbury conduit, of Boston Water-Works, is sixteen miles long,
with a grade of 1.056 feet per mile. The top is a semicircle of nine
feet diameter, and the bottom is an arc of 13.22 feet radius, struck
from a center 5.53 feet above the crown of the arch. The sectional
area is 56.75 square feet. The foundation is of concrete; the side
walls and spandrel backing of rubble stone masonry; the lining of
brick, four inches thick, and the arch of brick, twelve inches thick.
The Charles River is crossed by a granite bridge, 475 feet long and
75 feet high, with two segmental and five semicircle arches.
On the line of the Vanne conduit there is an aqueduct made entirely
of “beton,” which spans the valleys and quicksands in the great
forest of Fontainebleau, between La Vanne River and Paris.
CONDUIT DATA.--(_From Fanning._)
======================+========+========+========+=========+===========+
| | |DEPTH OF|HYDRAULIC| SINE OF |
Locality. | WIDTH | HEIGHT | WATER | MEAN |INCLINATION|
|IN FEET.|IN FEET.|IN FEET.| RADIUS. | OF WATER |
| | | | | SURFACE. |
----------------------+--------+--------+--------+---------+-----------+
Cochituate, Boston | 5. | 6.333 | 6.333 | 1.417 | .0000496 |
Croton, New York | 7.47 | 8.458 | 6.083 | 2.341 | .00021 |
Washington | 9. | 9. | 3.465 | 1.873 | .00015 |
Brooklyn | 10. | 8.667 | 5. | 2.524 | .0001 |
Sudbury, Boston | 9. | 7.667 | 5.3 | -- | .0002 |
Baltimore | 9. | 9. | -- | -- | -- |
Loch Katrine, Glasgow | 8. | 8. | 6.85 | 2.525 | .0001587 |
Canal of | | | | | |
Isabel III, Mad. | 7.052 | 9.184 | -- | -- | -- |
Vanne, Paris | 6.6 | 6.6 | 5. | -- | .0001 |
Dhues, “ | 2.3 | 3.5 | -- | -- | .0001 |
Pont du Gard, Nismes | 4. | -- | 3.333 | -- | .0004 |
Pont Pyla, Lyons | 1.833 | -- | 1.833 | -- | .00166 |
Metz | 3.167 | -- | 2.167 | -- | .001 |
======================+========+========+========+=========+===========+
======================+==========+========+===============+=============
| VELOCITY | |
Locality. |PER SECOND|COEFFIC-|DAILY DELIVERY | TOTAL DAILY
| IN FEET. | IENT M.|AT GIVEN DEPTH,| CAPACITY,
| | | U.S. GALLONS. |U.S. GALLONS.
----------------------+----------+--------+---------------+-------------
Cochituate, Boston | 1. | .00452 | 16,398,000 | 16,500,000
Croton, New York | 2.218 | .00643 | 59,340,000 | 100,000,000
Washington | 1.893 | .00505 | 27,560,000 | 100,000,000
Brooklyn | -- | -- | -- | 70,000,000
Sudbury, Boston | -- | -- | -- | 70,000,000
Baltimore | -- | -- | -- | 170,000,000
Loch Katrine, Glasgow | 1.7126 | .00876 | 60,000,000 | 60,000,000
Canal of | | | |
Isabel III, Mad. | -- | -- | -- | 52,000,000
Vanne, Paris | -- | -- | -- | 23,500,000
Dhues, “ | -- | -- | -- | 5,500,000
Pont du Gard, Nismes | 2. | -- | -- | 14,000,000
Pont Pyla, Lyons | 2.95 | -- | -- | --
Metz | 2.738 | -- | -- | --
======================+==========+========+===============+=============
DAMS.
The disastrous failures of earth dams has excited suspicion as to
the stability of such structures; but when we consider the immensity
of the dams in India, our concern should be only for the care and
attention given to their construction. There the material used is
well puddled; then a drove of cattle is turned loose on the fill, to
stamp the earth thoroughly. This method is repeated in layers until
the required height is reached. Often the Sepoys do the stamping.
The Veranun reservoir dam is twelve miles in length; and the amount
of earth, of which it is composed, will encircle the globe with a
belt six feet in thickness.
There is a dam on the island of Ceylon made of huge stone blocks
strongly cemented together and covered over with turf, making a solid
barrier of fifteen miles in length, one hundred feet wide at the
base, sloping at top to forty feet, and extending across the lower
end of a spacious valley.
DIMENSIONS OR RESERVOIR DAMS.--(_From C. H. Beloe._)
==================+=============+=============++===================++
NAME OF WORKS. | NAME OF |MAXIMUM DEPTH|| RATIO OF ||
| RESERVOIR. |OF RESERVOIR.|| SLOPES. ++
| | ++---------+---------++
| | || INNER. | OUTER. ||
------------------+-------------+-------------++---------+---------++
| | || | ||
Bolton Water-Works|Heaton. | 35 || 3 to 1 | 2 to 1 ||
“ “ “ |Wayoh. | 76 || “ | 2½ to 1 ||
Liverpool |Roddlesworth.| 64 || “ | 2 to 1 ||
“ | “ | 78 || “ | “ ||
“ |Anglezark. | 35 || “ | “ ||
Bradford |Stuben. | 55 || “ | “ ||
“ |Chelker. | 36 || “ | “ ||
“ |Barden. | 68 || “ | “ ||
“ |Doe Park. | 52 || “ | “ ||
“ |Silsden. | 78 || “ | “ ||
“ |Gwmwith. | 66 || “ | “ ||
Rhyl District |Llanefwydd. | 52 || “ | “ ||
Warrington W. W. | -- | 13 || 1½ to 1 | “ ||
==================+=============+=============++===================++
==================+================================++======+======
NAME OF WORKS. | PUDDLE WALLS. || |
|------+--------+-------+--------++ WIDTH| WIDTH
| MAX. | THICK- | THICK-| ||OF TOP|OF DYE
|DEPTH.|NESS AT |NESS AT| BATTER.|| BANK.| WASH.
| |SURFACE.| TOP. | || |
------------------+------+--------+-------+--------++------+------
| ′ | ′ ″ | ′ | || ′ ″ | ′
Bolton Water-Works| 6 | 8 3 | 4 | 1 in 15|| 13 6 | 12
“ “ “ | 70 | 20 6 | 8 | 1 in 12|| 22 | 105
Liverpool | 120 | -- | 6 | 1 in 12|| 16 | 60
“ | -- | -- | 6 | 1 in 12|| 18 | --
“ | 50 | -- | -- | -- || 30 | --
Bradford | 40 | 12 | 6 | 1 in 18|| 12 | 15
“ | 30 | 12 | 6 | 1 in 12|| 12 | --
“ | 64 | 15 | 6 | 1 in 15|| 12 | 24
“ | 78 | 12 | 6 | 1 in 18|| 12 | 15
“ | 40 | 12 | 6 | 1 in 24|| 12 | 15
“ | 50 | 14 | 6 | 1 in 18|| 12 | 40
Rhyl District | 119 | 9 | 3 | 1 in 18|| 10 | 12
Warrington W. W. | -- | -- | -- | -- || 3 | --
==================+======+========+=======+========++======+======
One of the recent dams of the Croton supply, made of concrete, is
thirty-one feet at the base, eight and one-half feet at top, six
hundred and seventy feet long, and seventy-eight feet high. The main
embankment, which forms Lough Vartry of the Dublin Water-Works, is
sixty-six feet high at its deepest part, and the greatest depth of
water, sixty feet. It is 1,640 feet long on the top, and twenty-eight
feet wide, which forms a public road. The base, at the deepest part,
is 380 feet wide; the inner slope being 3 to 1, and the outer slope
2½ to 1, and the total quantity of earthwork in it is 320,000 cubic
yards. The puddle wall in the embankment is six feet wide at the top
(one foot below the top bank), and eighteen feet wide at the level of
the old river bed. It was carried, for its entire length, down into
solid rock.
The dam of Bradlee basin, Boston, is 2,000 feet in length, twenty
feet wide on top, one hundred and fifty feet at the base, and
greatest height thirty-five feet. In the center of the bank is a
puddle wall ten feet thick at the base, and four feet at the top,
founded on the rock. The earth embankment was laid in layers, well
watered and rolled.
COMPARISON OF LARGE GRAVITATION WORKS.
==========+========+=========+============+==========+===========+=========
|DISTANCE|NO. ACRES| CAPACITY |HEIGHT OF |CAPACITY OF|
| OF SRCE| OF WATER| OF STORAGE.|SRCE ABOVE| AQUEDUCT | POPULA-
| IN | SHED. | IN GALLONS.|CITY DATUM|IN GALLONS.| TION.
| MILES. | | | IN FEET. | |
----------+--------+---------+------------+----------+-----------+---------
New York | 40 | 216,844 | 9 billions| 160 |92 millions|1,216,500
Boston | 16 | 100,000 | -- | 134 | 86 “ | 412,000
Baltimore | 7 | -- |765 millions| 165 |170 “ | 332,190
Liverpool | -- | 10,000 | 4 billions| -- | 17 “ | 600,000
Manchester| 18 | 19,390 | 6 “ | 790 | 39 “ | 750,000
Glasgow[1]| 25¾ | 47,800 | 12 “ | -- | 50 “ | 550,000
Dublin | 21.6 | 14,080 | 2½ “ | 692 | 20 “ | 330,000
==========+========+=========+============+==========+===========+=========
[1] Gorbals not included.
The dam for diverting the waters of Gunpowder Falls, for supply of
Baltimore, is built of rubble and white marble upon solid rock.
Thickness at base is sixty-two feet; depth of foundation below
original surface is thirteen feet; width of the overflow is three
hundred feet. The wings extend into the hill on each side two hundred
and fifty-six feet. The height from the extreme foundation to the
overflow is twenty-nine feet. The filling of the clay and earth on
the inside is forty-five feet at the base.
Liverpool, Eng., designs constructing a masonry dam, at the source of
the new supply in Wales, eighty-four feet in height.
PUMPING SYSTEM.
The divisions of power are:
Wind Power.
Water Power.
Steam Power.
And the methods of supply by:
Reservoir.
Stand Pipe.
Direct or Holly Plan.
The value of a pumping system recommends itself on the point of
economy in construction, for the outlay is in proportion to the
existing necessities, which can be increased as the demands require.
The original water consumers are not, therefore, taxed so heavily
for future exigencies of gravity works. This idea can be better
illustrated by the comparative cost of construction and maintenance
of gravitation and pumping works:
========================================+=============+=============+
| BALTIMORE | CHICAGO |
|GRAVITATION. | PUMPING. |
----------------------------------------+-------------+-------------+
Available capacity for daily supply |200 millions |120 millions |
Largest daily consumption in 1880 | -- | 73 “ |
Total valuation of works | 10 “ | 8.8 “ |
Bonded indebtedness | 9 “ | 3.9 “ |
Annual interest |440 thousands|283 thousands|
Annual current expenses | 87.5 “ |206 “ |
Annual maintenance, including interest }| | |
at 5 per cent on total valuation }|587.5 “ |646 “ |
of works. }| | |
========================================+=============+=============+
========================================+=============+=============
| BOSTON | CINCINNATI
|GRAVITATION. | PUMPING.
----------------------------------------+-------------+-------------
Available capacity for daily supply | 86 millions | 36 millions
Largest daily consumption in 1880 | 28 “ | 38 “
Total valuation of works | 18 “ | 7 “
Bonded indebtedness | 12 “ | 1.6 “
Annual interest |619 thousands|108 thousands
Annual current expenses |211 “ |200 “
Annual maintenance, including interest }| |
at 5 per cent on total valuation }|1,111 “ | 50 “
of works. }| |
========================================+=============+=============
The reservoir system is the most preferable of the three methods,
when natural elevation can be secured, for the pumping service is
distinct from the distribution; and, where reservoirs of large
capacities are obtainable, a closer margin for reserve pumping
power can be adopted, besides a storage reservoir provides for
contingencies that may arise, and allow cessation of pumping during
the turbidity of water source, caused by sudden freshets.
The stand-pipe is adopted where the elevated grounds are not
sufficient for reservoir purposes, to give a desirable water
pressure; or where reservoirs may not be desired, but to secure the
head and provide for a constant and reliable action of the pump that
is not obtained by a direct system.
The direct system, commonly called the Holly Plan, does away with
reservoir and stand pipe, and delivers the water directly into the
mains under a pressure usually fifty pounds per square inch for
domestic use, which is increased to one hundred pounds when fires
occur. In the Holly Plan, a reserve power is used for fire purposes,
besides mechanical device for regulating and controlling the variable
pressure.
In either the stand pipe or direct system, a reserve power should be
provided equal to the largest daily consumption.
From a compilation of general information concerning water-works of
the United States and Canada, published by the Holly Manufacturing
Company in 1878, we arrange the following:
188 cities and towns use steam-power for water supply.
104 “ have gravity works “
32 “ use water-power “
10 “ have gravity and steam works “
27 “ use steam and water-works “
2 “ have gravity, steam, and water-powers “
Of the above number of pumping works--
139 have reservoir system.
98 have direct system.
16 have stand-pipe system.
4 have direct and reservoir combined.
1 has the three systems combined.
1 has stand-pipe and direct combined.
The expense of pumping water by steam and water-powers, also the
practical yearly duties of various pumping engines, are given in the
tables on pages 61 and 64, compiled from annual reports for 1880:
PRACTICAL DUTIES (WITHOUT DEDUCTIONS) OF PUMPING ENGINES (YEARLY
AVERAGE).
(_From Annual Reports of 1880._)
---------------------+-----------------+----------------------------+
| NON ROTATIVE. | ROTATIVE. |
+--------+--------+--------+---------+---------+
| WORTH- |CORNISH.| HOLLY. | LOW | HIGH |
| INGTON.| | |PRESSURE.|PRESSURE.|
---------------------+--------+--------+--------+---------+---------+
Louisville, Ky. { | -- |44189515| -- | -- | -- |
{ | -- |45544384| -- | -- | -- |
| | | | | |
{ | -- | -- | -- |59550000 | -- |
Brooklyn, N. Y. { | -- | -- | -- |56004900 | -- |
{ | -- | -- | -- |68378000 | -- |
| | | | | |
Albany, N. Y. { | -- | -- | -- | -- | -- |
{ | -- | -- | -- | -- | -- |
| | | | | |
Toronto, Canada { |38477030| -- | -- | -- | -- |
{ |38726890| -- | -- | -- | -- |
| | | | | |
Toledo, O. |36399973| -- | -- | -- | -- |
Boston; high service |51063000| -- | -- | -- | -- |
Charleston, Mass. |52845400| -- | -- | -- | -- |
Columbus, O. | -- | -- |28758135| -- | -- |
Chicago, north side | -- | -- | -- |52956684 | -- |
Chicago, west side | -- | -- | -- | -- | -- |
| | | | | |
Phila., Schuylkill { | -- |24342000| -- | -- | -- |
{ | -- |35360000| -- | -- | -- |
| | | | | |
{ |39000000| -- | -- | -- | -- |
Phila., Belmont { |37900000| -- | -- | -- | -- |
{ |44870000| -- | -- | -- | -- |
| | | | | |
Phila., Delaware | -- | -- | -- | -- |39000000 |
Phila., Roxborough |38280000|36280000| -- | -- | -- |
Phila., Frankfort |27000000| -- | -- | -- | -- |
Lawrence, Mass. | -- | -- | -- | -- | -- |
Dayton, O. | -- | -- |15000000| -- | -- |
| | | | -- | -- |
Cleveland, O. { |42397185|30361497| -- | -- | -- |
{ | |31925636| -- | -- | -- |
| | | | | |
Lynn, Mass. | -- | -- | -- | -- | -- |
Pawtucket, R. I. | -- | -- | -- | -- | -- |
Lowell, Mass. |59112831| -- | -- | -- | -- |
| | | | | |
{ | -- | -- | -- | -- |44304907 |
Cincinnati, O. { | -- | -- | -- |38014283 |38953517 |
{ | -- | -- | -- | -- |45886944 |
---------------------+--------+--------+--------+---------+---------+
---------------------+-----------------------+--------------
| COMPOUND. |
+--------+--------------+
|LEAVITT.|MISCELLANEOUS.|MISCELLANEOUS.
| | |
---------------------+--------+--------------+--------------
Louisville, Ky. { | -- | -- | 20280502[2]
{ | -- | -- | 19572536
| | |
{ | -- | -- | --
Brooklyn, N. Y. { | -- | -- | --
{ | -- | -- | --
| | |
Albany, N. Y. { | -- | 70991413 | --
{ | -- | 70327595 | --
| | |
Toronto, Canada { | -- | -- | --
{ | -- | -- | --
| | |
Toledo, O. | -- | -- | --
Boston; high service | -- | -- | --
Charleston, Mass. | -- | -- | --
Columbus, O. | -- | -- | --
Chicago, north side | -- | -- | --
Chicago, west side | -- | 58808495 | --
| | |
Phila., Schuylkill { | -- | 49726000 | --
{ | -- | 55633000 | --
| | |
{ | -- | -- | --
Phila., Belmont { | -- | -- | --
{ | -- | -- | --
| | |
Phila., Delaware | -- | -- | --
Phila., Roxborough | -- | -- | 28380000[3]
Phila., Frankfort | -- | 57160000 | --
Lawrence, Mass. |98583176| -- | --
Dayton, O. | -- | -- | --
| | |
Cleveland, O. { | -- | 29558769 | --
{ | -- | -- | --
| | |
Lynn, Mass. |92843506| -- | --
Pawtucket, R. I. | -- | -- | 96046816[4]
Lowell, Mass. | -- | 76108012 | --
| | |
{ | -- | -- | --
Cincinnati, O. { | -- | -- | 21665474[5]
{ | -- | -- | --
---------------------+--------+--------------+--------------
REMARKS.--
[2] Blake pump;
[3] Knowles;
[4] Corliss;
[5] Low pressure, direct acting.
The term, duty of a pumping engine, is a conventional one, used by
engineers to measure the relative merits of performance, or effective
work, expressed by the ratio of product in foot pounds of the weight
water into the height it is lifted, to one hundred pounds of the coal
consumed to lift the water. The following tables of expert trials are
taken from “Manual for Engineers and Steam Users,” by John W. Hill,
M. E. (1878), with a few additions:
PERFORMANCE OF PUMPING ENGINES.
---------------+-----+-------------------------------+--------------+
| | | |
LOCATION. |DATE.| ENGINE. | DESIGNER. |
| | | |
---------------+-----+-------------------------------+--------------+
| | | |
United Mines, |Sept.|Cornish single cylinder, |Taylor |
Cornwall |1842 | jacketed | |
| | | |
Carn Brea, |1841 |Cornish compound, jacketed |James Sims |
Cornwall | | | |
| | | |
Lynn, Mass. |Dec. |Compound beam and fly-wheel, |E. D. Leavitt |
|1873 | jacketed | |
| | | |
Lowell, Mass. |June |Compound beam and fly-wheel, |Simpson |
|1875 | jacketed | |
| | | |
Lawrence, Mass.|May |Compound beam and fly-wheel, |E. D. Leavitt |
|1876 | jacketed | |
| | | |
Trenton, N. J. |Mar. |Compound beam and fly-wheel, |Wm. Wright |
|1876 | jacketed | |
| | | |
Milwaukee, Wis.|May |Compound beam and fly-wheel, |R. W. Hamilton|
|1875 | jacketed | |
| | | |
Marion, Ind. |Feb. |Single cylinder yoke and |Dean |
|1877 | fly-wheel, condensing | |
| | | |
Haarlem Meer, |June |Compound beam annual cylinder |Gibbs & Dean |
Holland |1848 | | |
| | | |
Chicago |Dec. |Single cylinder beam and |D. C. Creiger |
|1874 | fly-wheel, unjacketed | |
| | | |
Chicago |April|Compound beam and fly-wheel, |Quintard Works|
|1877 | unjacketed | |
| | | |
Chicago |April|Compound beam and fly-wheel, |Quintard Works|
|1877 | unjacketed | |
| | | |
Chicago |April|Compound beam and fly-wheel, |Quintard Works|
|1877 | unjacketed | |
| | | |
Cincinnati |Nov. |Horizontal crank and fly-wheel,| |
|1872 | two engines coupled, |Shield |
| | non-condensing | |
---------------+-----+-------------------------------+--------------+
---------------+--------------+-----------+------------------------
| DUTY FOR ONE | |
LOCATION. | HUNDRED | CAPACITY. | AUTHORITY.
| POUNDS COAL. | |
---------------+--------------+-----------+------------------------
| | |
United Mines, |114,361,700[6]| -- | Pole.
Cornwall | | |
| | |
Carn Brea, |101,702,000[6]| -- | Pole.
Cornwall | | |
| | |
Lynn, Mass. |103,923,215 | 4,938,528 | Experts’ Contract Trial.
| | |
Lowell, Mass. |117,350,100[6]| -- | Evans’ Annual Report.
| | |
Lawrence, Mass.| 96,201,900 |Each eng’e | Experts’ Contract Trial.
| | 4,979,234 |
| | |
Trenton, N. J. | 84,500,000 | 2,086,523 | Slade.
| | |
Milwaukee, Wis.| 76,955,520 |Each eng’e | Expert’s Contract Trial.
| | 8,683,720 |
| | | Two eng’es
Marion, Ind. | 49,231,207 | Two eng’e | Cook.
| | cupled |
| | 1,500,000 |
| | |
Haarlem Meer, | 80,000,000[6]|200,000,000| Appleton’s Dictionary.
Holland | | |
| | | Two eng’es
Chicago | 65,824,581 |Two eng’es | Experts’ Contract Trial.
| | cupled |
| | 36,000,000|
| | |
Chicago |West engine | 16,160,470| Experts’ Contract Trial.
| 99,082,300 | |
| | |
Chicago |East engine | 15,571,970| Experts’ Contract Trial.
| 96,066,800 | |
| | |
Chicago | 75,000,000 | -- | Theron Skeel.
| | |
Cincinnati | 43,566,178 | 4,702,805 | Hermany.
---------------+--------------+-----------+------------------------
[6] Said to be average duty; all others obtained by special tests.
The capacity is stated in delivery of gallons per day of twenty-four
hours.
PERFORMANCE OF PUMPING ENGINES.
-----------------+-----+-------------------------------+-----------------+
| | | |
LOCATION. |DATE.| ENGINE. | DESIGNER. |
| | | |
-----------------+-----+-------------------------------+-----------------+
Cincinnati |Nov. |Vertical single cylinder crank | Scowden |
|1872 | and fly-wheel, condensing | |
| | | |
Cincinnati |Nov. |Vertical single cylinder crank | Scowden |
|1872 | and fly-wheel, condensing | |
| | | |
Cincinnati |Nov. |Vertical direct acting single | Shield |
|1872 | cylinder, condensing | |
| | | |
Louisville |1873 |Cornish | Scowden |
| | | |
Newark, N. J. |1870 |Compound duplex | Worthington |
| | | |
Cleveland, O. |1873 |Cornish | Allaire Works |
| | | |
Jersey City |1856 |Cornish | W. Point Foundry|
| | | |
Charleston, Mass.|1872 |Duplex | Worthington |
| | | |
Providence |1874 |Radial cut off | Geo. H. Corliss |
| | | |
Providence |1874 |Compound duplex | Worthington |
| | | |
New Bedford, Mass|1869 |Beam and fly-wheel | McAlpine |
| | | |
Brooklyn, No. 1 |1860 |Single cylinder beam | Wright |
| | | |
Cleveland, O. |1875 |Compound duplex | Henderson |
| | | |
Cincinnati, O. |Mar. |Compound direct acting | Warden |
|1879 | | |
| | | |
Columbus, O. |Feb. |Crank and fly-wheel, | B. Holly |
|1876 | four engines coupled | |
| | | |
Pawtucket, R. I. | -- |Compound beam and | H. Corliss |
| | fly-wheel, steam jacket Geo. | |
| | | |
Buffalo, N. Y. |1879 |Holly, four cylinders, | Holly Co. |
| | with fly-wheel | |
-----------------+-----+-------------------------------+-----------------+
-----------------+--------------+----------+-------------------------
| DUTY FOR ONE | |
LOCATION. | HUNDRED |CAPACITY. | AUTHORITY.
| POUNDS COAL. | |
-----------------+--------------+----------+-------------------------
Cincinnati | 37,789,990 | 4,651,987| Hermany.
| | |
Cincinnati | 34,064,977 | 4,263,297| Hermany.
| | |
Cincinnati | 23,580,687 |11,847,481| Hermany.
| | |
Louisville | 37,536,730[7]| 3,816,575| Journal A. S. C. E.
| | |
Newark, N. J. | 77,157,840 | -- | Bailey.
| | |
Cleveland, O. | 41,774,955[7]| 5,711,988| Journal A. S. C. E.
| | |
Jersey City | 72,115,396 | -- | Copeland & Worthen.
| | |
Charleston, Mass.| 56,937,643[7]| -- | Journal A. S. C. E.
| | |
Providence | 25,865,000 | -- | Smith, Graff & Reynolds.
| | |
Providence | 53,528,210 | -- | Smith, Graff & Reynolds.
| | |
New Bedford, Mass| 59,336,497 | -- | Hoadley & Francis.
| | |
Brooklyn, No. 1 | 60,798,200 |15,439,653| Smith, Graff & Worthen.
| | |
Cleveland, O. | 31,968,006[7]| 8,400,000| Annual Report.
| | |
Cincinnati, O. | 53,957,957 | 2,000,000| Hill.
| | |
Columbus, O. | 24,045,951 | -- | --
| | |
Pawtucket, R. I. |133,522,090 | -- | Contract Trial.
| | |
Buffalo, N. Y. | 86,176,315 | 6,502,000| Park Benjamin.
-----------------+--------------+----------+-------------------------
(A. S. C. E. is the American Society of Civil Engineers.)
[7] Said to be average duty; all others obtained by special tests.
The capacity is stated in delivery of gallons per day of twenty-four
hours.
COST OF PUMPING ONE MILLION GALLONS OF WATER,
(_From Annual Reports, 1880._)
-------------------+----------+--------+--------+-----------------------+
| | | | COST OF PUMPING ONE |
| | | | MILLION GALLONS. |
| MILLIONS |AVERAGE |COST OF +-------+-------+-------+
CITY. |OF GALLONS| LIFT | COAL | FOR | FOR | FOR |
| PUMPED. |IN FEET.|PER TON.| WAGES.| COAL. |REPAIRS|
-------------------+----------+--------+--------+-------+-------+-------+
St. Louis, Mo. | 9944 | 50. | $2.66 | $1.57 | $2.85 | $ .15 |
St. Louis, Mo. | 9857 | 225. | 2.66 | 3.17 | 8.19 | .31 |
Charleston, Mass. | 3434 | 150.8 | 4.81 | 2.03 | 5.73 | .09 |
Boston, Mass. | 856 | 116.4 | 5.07 | 4.32 | 4.82 | -- |
Philadelphia, Penn.| 13232 | 124. | 3.34 | 2.64 | 3.72 | .41 |
Philadelphia, Penn.| 7887 | 100. | 3.34 | 1.33 | .10 | .35 |
Columbus, O. | 912 | 175. | 1.37 | 8.10 | 3.48 | .16 |
Chicago, Ill. | 12354 | 104. | 4.00 | 1.73 | 3.36 | .10 |
Chicago, Ill. | 8648 | 98. | 3.60 | 2.32 | 2.67 | -- |
Dayton, O. | 387 | 127. | 2.70 | 16.68 | 8.88 | -- |
Brooklyn, N. Y. | 11196 | 163. | 4.40 | 3.03 | 5.27 | -- |
Pawtucket, R. I. | 325 | 262. | 4.86 | 7.57 | 5.51 | -- |
Toledo, O. | 1193 | 160. | 2.28 | 4.32 | 4.63 | -- |
Montreal, Can. | 3095 | 165. | -- | -- | -- | -- |
Montreal, Can. | 452 | 165. | -- | 7.28 | 8.85 | 3.02 |
Lowell, Mass. | { 771 | 165. | 4.40 | 3.07 | 4.25 | .20 |
| { 52 | 166. | 4.40 | 3.74 | 5.54 | -- |
Cincinnati, O. | 2325 | 171. | 2.79 | 6.53 | 5.38 | 2.06 |
Cincinnati, O. | 4959 | 245. | 2.86 | 4.00 | 7.66 | 1.59 |
Cincinnati, O. | 563 | 293. | 3.15 | 12.50 | 8.49 | 2.69 |
-------------------+----------+--------+--------+-------+-------+-------+
-------------------+---------------+----------+--------------------+
|COST OF PUMPING| | |
| ONE MILLION | COST PER | |
| GALLONS. | MILLION | |
|-------+-------+ ONE | |
CITY. | FOR | | HUNDRED | REMARKS. |
|STORES.| TOTAL.| FT. HIGH.| |
-------------------+-------+-------+----------+--------------------+
St. Louis, Mo. | $ .18 | $4.75 | $9.50 | Low service. |
St. Louis, Mo. | .36 | 12.03 | 5.34 | High service. |
Charleston, Mass. | .30 | 8.15 | 5.40 | |
Boston, Mass. | .47 | 9.69 | 8.30 | High service. |
Philadelphia, Penn.| 1.49 | 8.27 | 6.68 | Steam. |
Philadelphia, Penn.| .20 | 1.98 | 1.98 | Water. |
Columbus, O. | .41 | 12.15 | 6.90 | Holly. |
Chicago, Ill. | .49 | 5.68 | 5.42 | North works. |
Chicago, Ill. | .36 | 5.15 | 5.24 | West works. |
Dayton, O. | -- | 28.36 | 22.33 | Holly. |
Brooklyn, N. Y. | -- | 10.84 | 6.65 | -- |
Pawtucket, R. I. | .50 | 13.58 | 5.17 | -- |
Toledo, O. | -- | 9.25 | 5.77 | -- |
Montreal, Can. | -- | 1.98 | 1.20 | Water. |
Montreal, Can. | 1.05 | 20.20 | 12.53 | Steam. |
Lowell, Mass. | { .32 | 7.84 | 4.73 | Morris engine. |
| { .20 | 9.48 | 5.69 | Worthington engine.|
Cincinnati, O. | .40 | 14.37 | 8.40 | Low service. |
Cincinnati, O. | .42 | 13.67 | 5.58 | Middle service. |
Cincinnati, O. | .65 | 24.33 | 8.30 | High service. |
-------------------+-------+-------+----------+--------------------+
STAND PIPE.
New York has a stand-pipe, for high service use, 170 feet high.
Cleveland has a stand-pipe 148 feet high, 36 inches in diameter.
The stand-pipe at Louisville is 48 inches in diameter, 132 feet high,
made of ¼ to ½-inch wrought-iron plates, the whole incased in wood.
The Mt. Auburn High Service at Cincinnati is supplied by two
wrought-iron tanks (which answer the same purpose of stand pipes),
each 60 feet in diameter and 38 feet high, and made of wrought-iron
sheets 50″ by 140″, ¼″ to 7-16″ in thickness. The water surface is
483 feet above low water. The cost of each tank was $15,000.
The water-tower at Toledo consists of a wrought-iron stand pipe,
around which is built a masonry structure of solid stonework 36
feet square, commencing 16 feet below the natural surface, with a
vertical thickness, under base of stand-pipe, of 7 feet; thence, with
octagonal opening around the pipe, to a point near 3 feet above the
surface of the ground, at which point its inner diameter is 16 feet,
and outer dimensions 30 feet square. From this point, to a further
height of four feet, the wall is composed of ashlar-face and brick
backing; thence to a point 70 feet above the foundation of solid
brick-work with octagon interior and exterior squares, the corners
terminating in buttress walls; the top to be octagonal battering to
an external diameter at the top of 14 feet. The total height is 224
feet, and the cost about $25,000.
A steel plate stand-pipe designed by J. D. Cook, civil engineer
for Springfield, Ohio, is in course of erection by the Stacey
Manufacturing Company of Cincinnati, which will be 112 feet high, 30
feet in diameter, thickness of lower ring being 25-32″, and upper
ring 3-16″. The estimated cost is $35,000.
The stand-pipe of Southwark and Vauxhall Water-Works, London, is 178
feet high, made of three columns of cast-iron pipe, the center one
extending 50 feet higher than the other columns. The side pipes are
30 inch, and center 48 inch in diameter. The Grand Junction works,
London, has a similar structure of two columns 153 feet high, incased
in a brick structure.
The stand-pipe of East London Co. is 240 feet high and 3 feet in
diameter.
HUSBAND’S PATENT BALANCE VALVE.
This patent is designed to supersede the costly stand-pipe. Fixed
vertically, as near to the engine as practicable, is a strong casting
provided with two short-flanged branches, the lower one being
connected with the discharge outlet from the pumps, and the upper
one with the delivery main. Between these branches a gun-metal valve
of the double-seat description is placed, and is connected to an
additional water-tight hat working on the top of the valve-seating.
The seating is firmly held down by bolts passing through it and
fastened to the casing. A ram lined with gun-metal, and of the
same diameter as the upper valve, is secured water-tight into it
by a colter, and works vertically up and down, passing through a
stuffing-box packed with cup leather, bolted to the upper portion of
the casing. The head of the ram works in a cross-guide lashed with
gun-metal, and supported by four strong vertical pillars. The ram is
loaded with weights nearly equal to the minimum load of the engine;
the lowest weight is provided with lugs working loosely over the
vertical pillars, which are provided with adjusting nuts and leather
washers, for the purpose of preventing the valve from falling heavily
and injuring its seating. The action of the apparatus is as follows:
The water, on entering the casing from the pumps, acts upon the under
side of the upper valve. The area of the valve is the same as that of
the ram, which, being loaded somewhat under the working load of the
engine, is immediately lifted, raising the valve with it, and thus
giving the water free access to the delivery main.
In the event of the main being fractured at any point beyond the
valve, the pressure within the main is suddenly reduced on account of
the great escape of water, and is, consequently, unable to support
the loaded valve, which immediately closes; thus the working load
of the engine is retained, and the possibility of accident by racing
prevented.
FUEL EXPENSE FOR PUMPING COMPARED ON DUTY BASES.--(_Fanning._)
========+==============================================================
DUTY IN | NUMBER MILLION GALLONS PUMPED DAILY, ONE HUNDRED FEET HIGH.
MILLION | COAL IN FURNACE AT $8 PER TON.
FOOT +---------+--------+--------+--------+--------+--------+-------
POUNDS.| 1 | 2 | 3 | 4 | 6 | 8 | 10
--------+---------+--------+--------+--------+--------+--------+-------
100 |$1,277.86| $2,556 | $3,834 | $5,111 | $7,667 |$10,223 |$12,779
90 | 1,419.85| 2,840 | 4,260 | 5,679 | 8,519 | 11,359 | 14,198
80 | 1,597.32| 3,195 | 4,792 | 6,389 | 9,584 | 12,778 | 15,973
70 | 1,825.51| 3,651 | 5,477 | 7,302 | 10,953 | 14,604 | 18,255
60 | 2,129.76| 4,260 | 6,389 | 8,519 | 12,779 | 17,038 | 21,298
50 | 2,555.72| 5,111 | 7,667 | 10,223 | 15,334 | 20,446 | 25,557
40 | 3,194.65| 6,384 | 9,584 | 12,769 | 19,168 | 25,537 | 31,946
30 | 4,259.53| 8,519 | 12,779 | 17,038 | 25,557 | 34,076 | 42,595
20 | 6,389.30| 12,768 | 19,168 | 25,537 | 39,336 | 51,174 | 63,893
========+==============================================================
DIMENSIONS AND COST OF CONSTRUCTING PUMPING ENGINES.
==========+======+=================================+=========+===========+
| WHEN | |MAX. CAP-|DIAMETER OF|
CITY. |BUILT.| KIND OF TOWER. |ACITY IN | SYS. CYL. |
| | |MIL. GAL.| IN INCH. |
----------+------+---------------------------------+---------+-----------+
| | | | |
Chicago | 1876 |Compound condensing beam and { | 30 | 48 H.P. |
| | fly-wheel. { | | 76 L.P. |
| | | | |
“ | 1857 |Low-pressure beam and fly-wheel | 13 | 60 |
| | single eng. | | |
| | | | |
“ | 1857 |Double engine beam and fly-wheel.| 18 | 44 |
| | | | |
“ | 1872 |Double engine beam and fly-wheel.| 36 | 70 |
| | | | |
“ | 1853 |Single engine beam and fly-wheel.| 7½ | 44 |
| | | | |
Cincinnati| 1850 |Single engine fly-wheel. | 4½ | 45 |
| | | | |
“ | 1865 |Single engine direct acting. | 20 | 100 |
| | | | |
“ | 1874 |Double engines fly-wheels | 7½ | 28 |
| | and beams. | | |
| | | | |
“ | 1869 |Double horizontal engines, | 4 | 18 |
| | fly-wheel. | | |
| | | | |
“ | 1874 |Compound dir’t acting. { | 2 | 14 H.P. |
| | { | | 22½ L.P. |
| | | | |
St. Louis | 1875 |Double, with beam and one { | 25 | 50 H.P. |
| | fly-wheel. { | | 80 L.P. |
| | | | |
==========+======+=================================+=========+===========+
==========+=========+==========+=========+======================
| | DIAMETER | |
CITY. | STROKE |AND STROKE| COST. | REMARKS.
| IN FEET.| OF PUMPS.| |
----------+---------+----------+---------+----------------------
| | ″ ′ | |
Chicago {| 6 H.P. | 51 × 10 |$543,500 | with 6 boilers.
{| 10 L.P. | | |
| | | |
“ | 10 | 40 × 6¼ | 59,000 | “ 2 “
| | | |
| | | |
“ | 8 | 28 × 8 | 112,500 | “ 1 boiler.
| | | |
“ | 10 | 57 × 10 | 188,400 | “ 3 boilers.
| | | |
“ | 9 | 34 × 5½ | 24,500 | “ 1 boiler.
| | | |
Cincinnati| 8 | 18 × 8 | 30,000 | with 60 ft. iron col.
| | | |
“ | 12 | 46 × 12 | 200,000 | --
| | | |
“ | 8 | 25½ × 8 | 99,000 | Plunger 16½ “
| | | |
“ | 5 | 13¼ × 5 | 18,000 | with 1 boiler.
| | | |
“ | 2½ | 10 × 2½ | 8,600 | --
| | | |
St. Louis{| 7¼ H.P.| 45¼ × 8½ | 280,000 | Plunger 32″ dia.
{| 11½ L.P.| | |
| | | |
==========+=========+==========+=========+======================