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PROFESSIONAL PAPERS

INDIAN ENGINEERING.

EDITED BT

MAJOR A. M. LANG, R.E.,

PRXMCIPAL. THOMlflON a JL OOLLEGB, BOORKSB.

VOL. V.

<F~^'y\

ROORKEE :
PRINTED AND PUBLISHED AT THE THOMASON COLLEGE PRESS.

CALCUTTA : THACKEB, SPINK & CO. BOMBAY t THAGKEB, VOTING & GO.
MADRAS : GAHTZ, BBOTHKBS. LONDON : E. * F. N. BPON & CO.

1876.

[AU rights reserved by the Secretary of State for India in Council.']

THOS. D. BOHA, OFFO. 8UPBRIST1HDHKT.

PREFACE to VOL. V.

With the issue of this Quarterly No. XXII., the Fifth Volume of
the Second Series of Professional Papers on Indian Engineering is
brought to a close: and the complete series (1st and 2nd) of
these records on engineering experience in this country, now amounts
to twelve large Volumes, containing much valuable information on
a variety of subjects connected with every branch of the profession
as occurring in India.

This Volume is as varied in its contents as any of its predecessors,
and contains articles, both practical and theoretical, in most depart-
ments of Engineering. Of the thirty-five papers therein contained,
the largest number devoted to one subject is six, and these relate to
manufacture, experiments, or machinery, in connection with Cements
and Puzeolanas, the attention to which important materials is pro-
ducing a marked improvement in building generally throughout
the Country. Bailwaj matters form the subject of four papers : the
claims of the ' Central-Ladder-rail ' system are again brought before
the readers of this publication, as this, or some similar system, must
ere long engage the attention of Indian Engineers in connection
with the Himalayas, Nilgherries, and perhaps the ranges bounding
our North-Western frontier. Irrigation, and its cognate subject,
Drainage, occupy four articles. In the coming days of retrench-
ment, or at least increased economy, in Public Works, the sugges-
tions contained in Mr. Beresford's paper on the ' Duty of Water '
deserve the careful attention of those on whom rests the responsi-
bility of aligning canals and their distributaries, and the irrigation
of different soils and varying tracts of country.

IV PRRFACK.

The Construction of Roof 9 in wood or iron is treated of in five arti-
cles, some theoretical, others practical. In the former category may
be specially noticed, the paper No. CLXXXIX. on " Continuous
Uniform Beams," a most valuable contribution (by Captain Allan
Cunningham, R.E.) to the Mathematics of Engineering; in which
the problem is presented in a new and comparatively simple form,
novel at least to English Students. The specifications of roofs and
roof coverings (extracted from Mr. J. P. C. Anderson's book of Spec-
ifications) come under the second category; they will be found
useful to builders in most parts of India, and can be accepted as
reliable, being based on considerable and varied Indian experience.

Three papers are devoted to Bridge building : to one of these (No.
CCIII.) giving a description of the St. Joseph Bridge, exception
might be taken on the score of the work being American, not
Indian : but the conditions of the Missouri river in that locality are
so similar in many respects to those of the larger rivers of the
Punjab, that the description of the river-training works and the
foundation details of the American Bridge, will prove interesting
and instructive to the Indian Engineer: and the form of the
bridge itself is somewhat novel, and worthy of study as equally ap-
plicable to structures in this Country.

One paper devoted to the Harbour now under construction at
Madras, is valuable, as discussing a class of works as yet but little
studied by the profession in India, but for which a considerable
field exists on the coasts of this country with its extensive sea
board. The paper in question views the problem in two very
distinct lights: and during the prosecution of the work, the
conflicting opinions of the friends and foes of the present scheme
will receive illustration, very instructive to those who watch
the course of events.

Designs of Buildings are illustrated and described in two arti-
cles of this present Volume. In each case the architects are natives
of India; one, Rai Eunhya L&l Bahadur is an Engineer of long
and varied experience, and of high standing in the P. W. Depart-
ment : the other who is by profession a draftsman in a (Railway)

PREFACE. V

Chief Engineer's office, has already twice distanced all rivals in
competing for prizes offered to the furnisher of the best designs
for works of an oriental character. Teekaram's prize design for
the Alwar Rajah's Railway Station, was published in the IVth
Volume of this Series : and his design for the New Canning College
at Lucknow, — which won the prize, and was accepted for adoption
by the Committee, — is given in Paper No. CCX. of this new
Volume.

The remaining nine papers are on various subjects: the most
notable perhaps being an interesting article (No. CC.) on Dredgers
and Dredging, by Mr. J. W. Barns, M. Inst. C.E.

This series of papers will be continued in the same form, and
under the same terms, as heretofore, in a Vlth Volume, of which
the first issue, Quarterly Number XXIII. will be published in
January 1877.

A. M. L.

INDEX to VOL. V,

PAGE.

Beams, Continuous Uniform. By Capt. Allan Cunningham, R.E.,

Hony. Fellow of King's College, London, 107

Canning College, Lncknow, Design for. By Teekaram, Head Drafts-
man, Engineer-in-Chiefs office, Rajpootana (State) Railway, ... 897
Cements, Experiments on Strength of Indian. Extract from letter

from P. Dejonx, Esq., C.E., Exec. Engineer, 229

Cements, Farther Notes on Indian. By P. Dejonx, Esq., C.E.,

Exec. Engineer, Cement Experiments Division, 425

Circular Roof in Iron, 805

Compensator for Distant Signal Wires, Spencer's Patent. By (the

late) C. I. Spencer, Esq., M. Inst. O.E., 202

Concrete Bridges. By Lieut-Col. H. A. Brownlow, R.E., Snpdg.

Engineer, Irrigation Branch, Punjab, ... ... 893

Concrete in India, The use of. By Fitshugh Cox, Esq., Assist

Engineer, P. W. Dept., ... ••• ••• ••• ••• ••• 24

Concrete-mixing Machine, Stoney's. By Bindon B. Stoney, Esq.,

14. A., Mi Inst. O.Ui., ... •• ••• ••• •■• ••• o40

Damper for Ball's Kilns, Patent Combustible, 887

Drainage of Madras. Report by W. Clarke, Esq., M. Inst. C.E.,

Drainage Engineer of Madras, ... ... ... ... ... 288

Dredgers, Improved Method of Working Bull's. By W. Bull, Esq.,

Resident Engineer, Oudh and Rohilkhand Railway, ... ... 105

Dredgers and Dredging. By J. W. Barns, Esq., M. Inst. C.E.

and F.R.O.S., Supdt Canal Irrigation, Bahawalpur State, ... 278
Elasticity, The Limit of. By J. 0. Douglas, Esq., East India Govt.

Telegraph Dept., &c, 209

Falls on the Sokkor Canal. By Lieut.-Coi. J. LeMesurier, R.E., 205

Till INDEX.

PAGE.

Harbour at Madras, Formation of a. Report by W. Parkes, Esq.,
M. Inst. C.E., to Govt. Fort St. George, Madras, and * Notes ' on
the above Report by Robt. J. Baldrey, Esq., • 65

Iron Bridge oyer Missouri River at St. Joseph. Communicated
by Lieut,«Col. J. G« Medley, R.E., ... ... .., ... 315

Irrigation Duty of Water, and the principles on which its increase
depends, Memorandum on the. By J. S. Beresford, Esq., Exec.
Engineer, ••• ••• ... ••• ••• ••• ... ••• 408

Lightning Conductors, Construction of. By Dr. R. J. Mann, M.D.,

J? *X*.^x.D., ••• ... ... ... .»• •>•• ... ... • OOO

Mountain Railway, ' Oentral-Ladder-Rail '. Being translations from
the German and French, with illustrations. By Oapt. J, L. L.
Moranfc, B.E., Assoc. Inst. O.E. and F.R.G.S., 39

Pent Roofs, Timbering, of. By Major W. H. Mackesyy F.G.S.,
Assoc. Inst. O.E., Asst. Secy, P. W. Dept., Punjab, ... , ... 149

Piers of Large Bridges on the Scinde, Punjab and Delhi Railway,
Protection ofr ... ... ... .. ... ••• ... 20

Pile Drawing, Claws for, ... ... ... ... ... ... 212

Puzzolana made of Burnt Clay, Artificial. By P. Dejoux, Esq.,
Exec. Engineer, Cement Experiments Division, • 10

Railway in Johore. By H. Vacher, Esq., Exec Engineer,
P. W. Dept, Johore,. ••• ••• 342

Railway Traffic,. Indian,. • •• 14

Rajbaha Velocities and Discharges for Side Slopes 1 to 1, Tables
of. Computed for the Punjab Irrigation Department under su-
perintendence of Oapt. Allan Cunningham, R.E., Hony. Fellow of
King's College, London, •• •- ... 139

Roof Coverings, Specifications ior. By J. P. 0. Anderson, Esq.,
Assoc. Inst C.E., Supdg. Engineer, 4th Circle, Military Works, 213

Roofing Tiles, Moulding and Drying Sheds foe By H. Bull, Esq.,
Assist. Engineer, ... ... ... . ... ... ••• ... 313

Senate Hall for Punjab University College, . Lahore. By. . Rai
Kunhya Lall» Assoc*. Inst. C.E., Exec. Engineer, Lahore, , .~ 1

Slide-rule for finding Scantlings of Timber for Flat Rods. By
Lalla Ganga Ram, C.E., Assist. Engineer, P. W. D., Punjab,... 403

INDEX. IX

PAGE.

Sdrki Screen, Stoney's Patent Improved. By E. W. Stoney, Esq.,
jt, Inst* CI!**, ••■ ••• ••• ■•• ••• ••• *** «. oo

Thermantidote, Improved Form of. By H. Boll, Esq., Assist. En-
gineer, Military Works, Agra, . 384

Work and Wages. A Review by an Exec. Engineer, 178

Correspondence,

...

LIST OP PLATES.

Photogbapb.
Iron Bridge over Missouri River at St. Joseph (Frontispiece).

Lithographs.

Senate Hall for Punjab University College. Elevation (2) — Cross
Section (4)— Plan, ... ••• ••• ... ... ... 6

Artificial Pnzznolana made of Burnt Clay. Plan, Elevation and
Sections of Kiln, ••• ••• ••• ... ••• ... ... 10

Protection of Piers of Large Bridges on the Scinde, Punjab and
Delhi Railway. Plan and Section of Piers of the Satlej, Beas,
and Jumna Bridges, showing position of stone protection round
Piers, before and after Floods (20) — Sections of one of the
main Channels before and after deposit of stone (20) — Jumna
Bridge; Plan of River showing Cold Weather Channels of
1874-1875, and Stone Protection works (22)— Sutlej Bridge ;
ditto, (22) — Beas Bridge ; ditto, 22

Stoney's Patent Improved Surki Screen. Plan, Section and End
Jfilevation, ... ... ... ... ■•• .^. 36

* Central-Ladder-Rail ' Mountain Railway. Map of the Rigi Moun-
tain, showing the Central-Ladder-Rail Mountain Railways upon it
(40)— Details of Permanent Way ; Cross Section of Permanent
Way, Section of Rung and Longitudinal Section through Ladder
(42) — Skeleton Map of the Continent, showing position of pro*
posed Railway over the Alberg (49) — Mountain Railway over
the Alberg ; Enlarged Survey of Lines (50) — Longitudinal Sec-
tion, ••• ... ... ••• ... «. . o4

INDEX.

PAGE.

Formation of a Harboar at Madras. Plan of the Town and Road-
stead, showing the Harboar proposed in Mr. Parkes' Report
(66) — Plan of the Town and Roadstead, showing the Harboar
proposed by Mr. R. Baldrey, 100

Improved Method of Working Ball's Dredgers. Elevations, ... 105

Continuous Uniform Beams. Two equal Spans; Diagrams of
Shearing Force and Bending Moment for varying Uniform Load
(122)— Three equal Spans; ditto, (124)— Equal Spans— Uni-
form Load, ... ... ... ... ••. ... ... 126

Timbering of Pent Roofs. Frame and Stress Diagrams, 172

Spencer's Patent Compensator for Distant Signal Wires. Plan and
Vertical Section and General Arrangement, with Compensator,... 202

Fails on the Sukkur Canal. Plan and Longitudinal Section of
Falls for the Rahaja Month, Half Elevations up-stream and
downstream (206) — Front Elevation and Back of Gate (206)
— Enlarged Drawings of Gates,... ... ... ... 206

Specifications for Roof Coverings. Details of a Roof of Fir or
Deodar Timber, of 24 feet span, suitable to carry a covering of
Goodwyn or Allahabad Tiling ; General Elevation of Truss when
a double King-post is used, Method to be followed should a joint
in the Tie-beam be necessary (214) — Enlarged details connected*
with double King-post ; Details of Joint in Purlin, at Junction of
Principal Rafter with Tie-beam, Dimensions of Strap and Bolt,
Joint at Junction of Strut with Principal Rafter (214) — Details
of Joint in Ridge Pole, and Common Rafter, General Elevation
of Truss when a single King-post is used, Enlarged details
connected with single King-post (214) — General Elevation of
Trass when an Iron Tie-rod is used ; Details of Cast-iron Shoe,
and Method of supporting Pole Plate, of }*, 1*, l£", 3' Bolts, and
Joint in Pole Plate (214) — Elevation and Sections showing junc-
tion of Lean-too-roof with Main Wall, and Ridge Pole between
Trasses (21 4) — Flat roofs for Verandahs, showing approved me-
thod of laying Wail-plates, 220

Drainage of Madras. Plan of Madras (252) — Sections of Brick
Sewers, Manhole for Pipe Sewers, Outfall Culvert, Pipe Sewers,
and Plan and Section of Lampholes for pipe Sewers, 256

INDEX. XI

PAGE.

Dredgers and Dredging. New type of Dredger and Sections (280)
—Details (284) — Vertical Section, Elevation of Bncket Ladder,
and Plan and Elevation of Dredger Hall (298)— Plan of Hall
and Elevation of Backet Ladder (298) — Elevation and Section
of Ejector Pomp, ... ••• ••• ••• ••• ••• ••• 300

Circular Roof in Iron. Bird's eye view when set up (306)— Side
view (806)— Circular Roof in Plan, and Section of Half Circular
Iron Roof (306)— Plan of Loading, Section of Frame, and Dia-
gram of Stress, •>• ... ••• ••• ••• ••• ••• 308

Moulding and Drying Sheds for Roofing Tiles. Longitudinal Sec-
tion showing one end with the middle part for Tables, and Cross
section, ••■ ••• ••• ••• ••• ••■ ••• ••■ o*%

Iron Bridge over Missouri River at St. Joseph. Hannibal Bridge,
view from west shore below (316) — Plan and Elevation of Pier,
Break-water four as built in the Channels, Breakwater four as
designed (330) — Map of the Missouri River in the vicinity of
St Joseph, showing changes in the channel, location of bridge,
and position of breakwaters, ... 336

Stoney's Concrete-mixing Machine. Plan, Longitudinal Section
and End Elevations, Mixing blades, Rose, and Section of Blade, 352

Improved Form of Thermantidote. Longitudinal and Cross Sec-
uons, ■•• ... ••• ••■ ••■ ••• ••« ••• 004

Patent Combustible Damper for Bull's Kilns. Ground Plan, En-
larged Plan showing loading, and Cross and Longitudinal Sec-
•ions, ••• ••• ••• ••• ••• ••• ... ■•• t}oo

Design for Canning College, Lucknow. Front Elevation (897)—
Back Elevation (402)— Side Elevation (402)— Cross and Longi-
tudinal Sections, Longitudinal Section of Roof of Upper
Verandah, Details of Cornice, Stone Pillar, Fire-place, Skew
back and Tension Rod (402)— Plan and Details of Railing,
Cornices, Parapet, Corbel (402)— Plans, Elevations, Sections
of Servant's Houses, and Privy, 402

Slide-rule for finding Scantlings of Umber for Flat Roofs. Scale
(404)— Examples, ••• ••• ••• ... ... ••• 406

Memorandum on the Irrigation Duty of Water, and the principles
on which its increase depends. Details, ... ... 413

No. CLXXX.

SENATE HALL FOR PUNJAB UNIVERSITY COLLEGE,

LAHORE.

[Vide Plates L, H and IIL]

Designed and constructed by Rai Kunhya. Lal, A.I.C.E., Exec.
Engineer, Lahore.

There being no building available at Lahore sufficiently large for the
requirements of the Senate of the Punjab University College, a new
building is constructed, as per plan shown in Plate III., which has been
drawn up in communication with, and approved by, the Registrar and
the President of the Executive Committee of the Senate of the Punjab
University College.

The coat of the building is met from a donation of Rs. 25,000* (made
by H. H. the Nawab of Bhaw&lpur), and the interest accruing thereon,
since the donation was vested in Government Securities ; and the building
is to bear the name of the Donor in the inscription in the Front, {see
elevation of building, Plate I.)
The building is constructed according to the following Specification :—
The foundation to consist of concrete, 3 feet deep, overlaid with
2 feet of pucka masonry. Concrete to consist of one part of kunkur
lime, one part of lime siftings, and one part of broken bricks, well mixed
and consolidated. All masonry (foundation, plinth and superstructure)
to be of pucka bricks laid in good lime mortar, having six to ten per cent,
of stone lime mixed in it for pillars, arches, mouldings, and cornice work.
The bricks required for pillars and arches, and the exposed parts of all

* Which, with the interest accruing thereon, now amounts to about Be. 80,000.
VOL. V. — 8BC0ND SBBIS8. B

2 SENATE HALL FOR PUNJAB UNIVERSITY COLLEGE, LAHORE.

the walls, to be large, measuring 9" X 4£" X 3" ; those for the test of
the work to be of the usual size of small bricks used at Lahore.

Inside to be lime plastered and whitewashed, and outside to be dressed,
and rubbed smooth, of a light red stone color.

The flooring to be second class tiled, tiles 12" X 12" X 8", set in lime
mortar, with close joints, over 6 inches of concrete.

The roofs of Senate Hall, Library and Registrar's Boom, to be slated
(first class), carried over trasses of deodar wood, haying a light and
ornamental boarded ceiling, painted white, with blue edgings. Bound
openings 12 inches diameter fitted with iron wire netting f-inch mesh,
to be left in the ceiling at every 10 or 12 feet for purposes of ventilation.

The roof of all the remaining rooms, including verandahs, to be carried
over beams and burgahs of deodar wood, overlaid with second class ter-
race.

The dimensions of the trasses, beams, and burgahs, to be as per cal-
culations accompanying. Wall plates under tie-beams of trusses to be

6" x 4" ; under beams

Over 10 feet bearing, ••• ... •»• »•• ... •••

Under beams 10 feet bearing, •

And under burgahs, ••• ... ••• ... ••• •••

Straps for the trusses to be ••• ••• ••• ••• •••

JjOltB, ••• ••• ... *•• •»• ... ••• •••

Screw nuts, ... ••• ••• ... ••• ••• •••

Doors and windows to have semi-circular glazed fanlights over them.

The outer doors to be one-fourth panelled and three-fourths glazed,
and the inner ones to be entirely panelled. Windows to be entirely glazed.

Doors to be 2 inches thick, windows If inches thick, door frames 4£"
X 4£", window frames 4" x 4". After completion of work all spare ma-
terials to be removed, the ground outside to be trimmed, and the place
rendered neat and tidy, to be made over to the Registrar of the Punjab
University College. Proper approaches 20 feet wide, with syphons over
the rajbaha in front of the building, to be made, and a space of 12 feet
width all round the building to be metalled with broken bricks 6 inches*
thick, with a slope of 3 inches outwards, for the proper discharge of rain
water.

The compound to be enclosed with a wooden railing or hedge.

A house for the chowkeedar 10' x 10' to be built at the back of
the building.

*'x4"

4'x8'

—

8* x nm

2*x r

7- '

f* diameter.

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SBBATB HALL FOB PUNJAB UNIVER6ITY OOLLBQE, LAHOBB. 8

General Remarks.

The boOding to be constructed in a workmanlike manner — and good
materials approved by the officer in charge of the work to be used. All
bad materials rejected by the above officer to be removed from the work.

The wood to be well seasoned sound deodar, free from large knots
and flaws.

The bricks to be thoroughly burnt, of a cherry red color, giving a clear
ringing sound on being struck.

The lime to be fresh oopla burnt for plain work and plaster, and wood
burnt for pillars, arches, and cornice.

Calculations of Strength of Beams, $c.

Beams. — Beams 174 feet bearing.

Interval from centre to centre = — = 4*6 feet.
Weight acting at centre of each beam, at 100 ft>s. per super-
fieUd f^ = «xH|xl00 = 4|020 ^

Strength of beam 16* x 1<T = ™y**10 = 4,888 lbs.
Beams*— Beams 16 feet bearing.

Interval from centre to centre = -^- = 4*88 feet.
Weight acting at centre of each beam, at 100 lbs. per super-
ficW foot = "MX16X100 = 8,466 fibs.

Strength of beam 16' x 10* = *"* j^* l0 = 4,800 lbs.

£*zm«.— BeamB 12 feet bearing.

Interval from centre to centre =s 6 feet.
Weight acting at centre of each beam, at 100 lbs. per super-
ficial foot = 6 x 122x 10° = 8,600 fts.

Strength of beam 14' X 8' = W* * *™ = 8920 lbs.
Beams. — Beams 10 feet bearing.

Interval varying from 8 to 6 feet

Strength of beam 12' X 6' = 1U* * *Qm = 2,592 lbs.

This agrees to an interval of about 5 feet. In verandah, few intervals
exceed 5 feet, but as the coefficient of 300 is much on the safe side,
therefore 12* x 6* would suffice for all rooms 10 feet span.

SENATE HALL FOR PUNJAB UNIVERSITY COLLEGE, LAHORE.

Burgahs,— Bearing varying from 8 to 6 feet.

Strength of a burgah 4f x 8" of 5 feetbearing a *' *Q3 *53(y>

= 288 lbs.

5 y 100 x 1
Weight acting at centre of each burgah = ==

250 ft>s.
Thus, all burgahs may be of this dimension, even where the bearing
approaches to 6 feet, as the coefficient of 800 is much on the safe side.

Section of Truss for 24 feet span.

Span = 24 feet.

Bise = 6 „

Interval =s 5 „
Weight of roofing, acting vertically
Allowance for weight of trass

100 lbs. per square foot.
20

Total, ... 120 „ „

Wind pressure, acting normal to the roof surface = 80 fibs.

Notations used in formula*

W = Weight (in pounds) of roofing on one Truss.
W = Normal wind pressure.

• = Inclination of roof.

K = Normal reaction. »ZL!?^!i= | x 2,010 x(-fy)'== 1,885 ft*.

W = 18-4 x 2 x 5 X 120 =16,080 fibs.
W'= 18-4 x 5 x 80 ss 2,010 lbs.

8KHATB HALL. FOB PUNJAB UNIVERSITY COLLEGE, LAHOBB.

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8BNATB HALL FOR PUNJAB CKIVBBBITT OOLLBGB, LAHORB.

Section of Truss for 20 Jeet span.

Span
Rise

= 20 feet.
= 5 feet.

100 lbs. per square foot.
20

Interval = ^ = 6-1875.

Weight of roofing, acting vertically :
Allowance for weight of truss, =

Total, ... 120 „ „

Wind pressure, acting normal to the roof surface ss 80 lbs.

Notation a* in ihs Calculations above*

Hence W = 111 x 2 x 6-2 x 120 = 16,516 lbs.
W' b 114 x 6*2 x SO = 2,064-5 lbs.
B or normal reaction = |Wsec*i = } x 2,064 x (U)1

ss 1,878 fibs.

8KHATR HALL FOB PUNJAB UNIVBRRITT COLLEGE, LAHORZ.

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8 SBNATB HALL FOR PUNJAB UNIVERSITY COLLEGE, LAHORE.

Abstract of Cost of Constructing a Senate Hall at Lahore, for the

University College, Punjab.

c ft B&

43,425 Excavation in foundation and filling in plinth, at Bs. 2-8 per 100, 109

16,941 Concrete work in foundation, at Bs. 12-4 per 100, .. •• 2,075

7,647*54 Burnt bricks in lime mortar in foundation, at Bs. 16 per 100, • • 1,224

2,651 „ „ in interior plinth, at Bs. 18-4 per 100, .. •• 484

802 „ „ in exterior plinth, at Be. 85 per 100, .. •• 281

714 Brick-on-edge work in steps and exterior plinth, at Bs. 40 per 100, 286

1,762 Brick plain work in steps and exterior plinth, at Bs. 24 per 100, 420

5,921 Brick in superstructure, both sides dressed, at Bs. 40 per 100, •• 2,868

13,838 Brick in superstructure, one side dressed, at Bs. 85 per 100, •• 4,668

16,962 Brick in superstructure, plain work, at Bs, 24 per 100, •• •• 4,071

r.a

1,014 Outer cornices, at Bs. 0-6-0 per foot, •• * • 880

624 . Inner cornices, at Bs. 0-4-6 per foot, •• •• •• •• 175

No.

5 Fire places, at Us. 22 each, 110

8. ft.

7,595 Tiled floor, 2nd class, at Bs. 10 per 100 760

4,867 Flat terrace roof covering, 2nd class, at Bs. 8 per 100, •• • • 889

19,310 Lime plaster, 2ud class, at Bs. 8-9-0 per 100, 687

19,310 Whitewashing, at Bs. 0-4-0 per 100, 48

5,466 Slate roof covering, including ridging and zinc sheet, &c, at Bs.

40 per 100, 2,186

aft

1,099 Deodar wood for trusses, at Bs. 2-12-0 per foot, 8,022

205 „ beams from 18 to 20 feet long, at Bs. 2-12-0 per foot, 564

855*52 „ beams from 12 to 14 feet long, at Bs. 1-13-0 per foot, 645

644*17 „ burgahs and wall plates, at Bs. 1-4-0 per foot, •• 805
s. ft

3,941 Ceiling, at Rs. 0-4-0 per foot, 985

5,466 Planking, at Bs. 0-2-0 per foot, 688

No.

26 Sunshades, at Bs. 5-4-0 each, 186

s. ft

744 Doors, |th panelled and fths glazed, at Bs. 1 per foot, • • . • 744

884 Panelled doors, at Bs. 1 per foot, 884

868 Glazed doors and windows, at Bs. 0-12-0 per foot, • • .. 646
mds. srs.

80 20 Wrought-iron work, at Bs. 12-8-0 per maund, •• •• •• 1,009

s. ft

1,989 Spirit varnish of doors and windows, at Bs. 2 per 100, •• •• 40

1,685 Glazing doors and windows, at Bs. 0-4-0 per foot, . • • • 421

3,949 Painting white, with blue edging, at Bs. 4 per 100, • • • • 158

Carried forward, . • 30,963

SENATE BALL FOB PUNJAB UNIVERSITY COLLEGE, LAHORE. 9

Rs.

Brought forward, .. 30,963
eft.

742 Kucha pucka masonry, including inner kncha plaster, at Rs. 8 per

100 59

s. ft.

520 Outer pucka plaster, at Rs. 4 per 100, 21

100 Mad roof covering, 1st class, at Rs. 6 per 100, 6

eft

14 Burgahs and wall plates for roof, at Rs. 1 per foot, • • • • 14

6 Beams for wall plates for roof, at Rs. 1-8 per foot, . . . . 9

aft.

28 Battened doors, at Rs. 0-8-0 per foot, 14

r.ft.

800 Fence, round the compound, at Rs. 0-2-0 per foot, • • • • 100
c. fL

4,104 Brick metalling of approaches, at Rs. 4 per 100, 164

13,850 Earthwork of approaches, at Rs. 3 per 100, 42

1,442 Pucka masonry of syphon over the rajbaha in front of building,

at R& 30 per 100, 433

Levelling and clearing ground, . . . . • 125

Inscription in front of building, 100

No.

3 Ventilating shafts, at Rs. 165 each, 495

Total Rupees, . . 32,545
K. L.

VOL. V.— -8KCOHD SERIES.

10 ARTIFICIAL PUZZOLANA MADE OF BUKNT CLAY.

No. CLXXXI.
ARTIFICIAL PUZZOLANA MADE OF BURNT CLAY.

[ Vide Plate IV.]

Remarks on Artificial Pnzzolana made with Burnt Clay. By P.
Dejoux, Esq., Exec. Engineer, Cement Experiments Division.

Dated the 14th July, 1875.

Surki. — The most common kind of artificial pnzzolana, called generally
in India " siirki," is made with burnt bricks pounded, more or less.

The earth used for making these bricks is composed of fat earth and
sand, and the puzzolana thus obtained is of very inferior quality.

The practice of not carefully selecting the bricks burnt to the degree
required for transforming a clay into an active pnzzolana, leads to the
cause of the siirki being generally composed of large proportions of inert
matter, which does not impart any hydranlicity to the mortar.

Puzzolana made with fine or marly clays. — Artificial pnzzolana
ought to be made with either pure clay free from sand (or at any rate
not containing more than 5 per cent, of.it) or with marly clays which con-
tain carbonate of lime.

1st. Clay 8 not containing carbonate of lime, and, if any, in small pro-
portions.— Clays are hydratic combinations of silica and alumina.

The degree of calcination which transforms them into puzzolana with
the maximum of hydranlicity is the same as the calcination required for
expelling the water entirely.

Therefore to transform a clay into puzzolana, the calcination must be
regulated so as to expel the last particle of water without exceeding 1100
to 1800 degrees Fahrenheit. This is what Vicat calls " cuisson normals "
(normal calcination).

2nd. Clays containing more than 15 to 20 per cent, of carbonate of

ARTIFICIAL PUZZOLAHA MADE OF BURNT CLAY. 11

tone.— More calcination is necessary in these than the previous ones, so
as to decompose the carbonate, and cause the combination of the lime and
day, bat the temperature of 1300 to 1600 degrees Farenheit moat not be
exceeded ; consequently it is requisite to calcine them with a slow fire, but
much longer than the previous ones.

Therefore it leads to the conclusion that clay requires only slight calcina-
tion to be transformed into puzzolana*

Preparing the clay. — It has been noticed that contact with air during
the calcination of a puzzolana has great effect on its quality.

This has never been clearly explained, -but it is a fact. Consequently!
it is necessary to render the clay as porous as possible.

This can be done by adding either some straw or saw-dust to it before
either bricks or balls are made with it.

This precaution, however, is only necessary when large bricks or balls
are made, but it will be unnecessary if dry clay, as found in its natural
state, iB used in broken pieces, not exceeding the size of an egg»

Burning, — 1st Mode. The easiest way of burning puzzolana is Ob-
tained by means of a kiln built on the principle of alternate fires.

The annexed (Plate IV.,) is the drawing of a small kiln of this des-
cription, which I built for experimental purposes.

This design, however, could be enlarged for practical purposes, by in-
creasing each dimension proportionally to the cubical contents required.

When raw day in form of either bricks or balls (or even in pieces) has
been put on the grating A, and the kiln has been loaded, a fire is lighted
in the furnace B, and this fire is kept on for a certain number of hours,
determined by experience.

Suppose the calcination has taken place for 8 hours, it will be found
that after that time while the contents of the portion (a) will be well
burnt, those of the portion (b) being further from the flame will only be
half burnt.

The fire is then Btopped in furnace B, and lighted in furnace C, and
after 8 hours the contents of (c) will be found properly calcined, and as
(b) has now been in fact exposed to the action of a heat not so strong as
that to which (a) and (c) were subject, but whioh nevertheless lasted for
16 instead of 8 hours only, this portion even will be found well calcined,
and the entire contents of the kiln therefore must be found burnt almost
to the same degree.

12 ARTIFICIAL PUZZOLANA MADfi OF BURNT CLAY.

2nd Mode. Pozzolana can also be calcined by loading the top part of
a lime kiln with the raw clay, and the bottom with lime, and thus it
happens while the lime is well burnt, the clay is also calcined to a good
degree.

This process, however, can be useful when only a small quantity of good
puzzolana is required for any special works.

3rd Mode. Puzzolana is at times burnt in clamps. This burning,
however, is not only irregular, but a large portion frequently gets over-
burnt, and besides the puzzolana obtained by this process is inferior in
quality.

Grinding burnt Pozzolana. — Puzzolana made with any clay gives
mortar the maximum of hydraulicity only when it is pulverized into fine
powder, otherwise while only a feeble portion acts as puzzolana, the other
does as an inert body, much inferior to sand, and consequently the mortar
thus obtained is more absorbent and lighter than sand mortar.

General remarks about Puzzolana Mortars. — 1st. An artificial puz-
zolana affords always much better results with a fat lime than with a
lime yielding a fair degree of hydraulicity.

2nd. Good ordinary hydraulic lime when mixed with sharp sand, gives
after a certain time, superior mortar to any puzzolana mortar, the only
advantage of the latter consisting in quicker setting.

3rd. The cohesion of a puzzolana mortar, being the result of what we
may call a chemical combination, will be evidently much increased, —

By the fine state of the lime and puzzolana ;

By the drawing as close as possible of these two materials, which will
be obtained by a good trituration of the mortar ; and

By constant dampness, without which the affinity of one material with
the other will not take place, and therefore no combination.

\th. Pozzolana mortars without the admixture of such a hard sub-
stance as sand, are liable from constant dampness to expand, and they act
in the opposite manner when left exposed for some time to a dry atmos-
phere. Then they contract, cracks follow, and very often with the excep-
tion of the outside crust, they become friable and pulverulent.

The only remedy for this is to add a notable proportion of sand (rather
coarse). However it may here be said that puzzolana mortars generally
afford much better results when immersed always, or exposed to a certain
dampness, and not left dry for any length of time.

ARTIFICIAL. rUZZOLANA MADE OF BURNT CLAT. 13

Chemical action of a Puzzolana. — Both puzzolana and lime by in-
timate combination (chemically speaking) form quite a homogeneous mass,
where the lime is no more a body binding together such a hard substance
as sand, which keeps exactly both its form and volume : the pure lime
on the contrary disappears, to give place to a double silicate of lime
and alumina.

Note 1st. Nearly all these remarks are based on the last theory of
Vicat on artificial puzzolana, and have proved correct from practical tests
and experience.

Note 2nd. If surki is intended only to be used as a substitute for sand,
it most be calcined more, but will not require fine grinding.

P. D.

14 INDIAN BAILWAY TBAFFIO.

No. CLXXXIL

INDIAN RAILWAY TRAFFIC.

It is a well-known fact that the traffic on the opened lines of Indian
Railways is still in a very undeveloped state, and that while one or two of
the most important lines return a fair profit on the capital, that profit is
far below what it onght to be, considering the population and natural wealth
of the districts through which they run. On the other hand, many lines
do not earn anything like the interest guaranteed by Government to the
shareholders, and more than one does not even pay its working expenses.

The result of this state of things is, that the revenues of India are sad-
dled with the payment of something like three millions sterling annually,
being the amount required to make good the guaranteed interest — and as
this sum represents about the first cost of 60 miles of new railway of the
State pattern, it is evident the loss is not a slight one.

In the construction of the new State Railways, the Government has
wisely profited by the experience derived from the guaranteed lines
They have been made with a strict regard to economy, and their man-
agement promises to be equally economical ; rather too much so in the
opinion of many. But it is in the further development of traffic, both on
them and on the older lines, rather than in cheapness of management,
that a fair return for the cost is to be sought, and it is to this important
point that I wish to draw attention.

Two years ago I submitted two Memoranda to Government on this
subject, based chiefly on experience of the American Railways. These
were circulated by direction of the Government, with a -view of eliciting
the opinions of the various railway authorities — with what result I have
not heard. But as the subject is a very important one, I venture again
to bring it forward here at somewhat greater length, with a view to dis-
cussion by those interested in the matter.

INDIAN RAILWAY TRAFFIC. 15

The chief obstacles to the proper development of the Railway pas-
senger traffic in this country I take to be— lsf, The clearness of the pre-
sent fares ; 2nd, The want of facilities for the comfort and convenience
of the travelling public.

I. As regards the first, the assertion will perhaps surprise those who
simply compare the mileage rate with that charged in England. The third
class* rate on the guaranteed lines is §rf. per mile — as against Id. in
England. Bat the difference in tho value of money in the two countries is
altogether overlooked, and this difference cannot at the very lowest be set
down at less than 4 to l.f That is, where the English workman will
have Is. to spend on travelling, his Indian brother will only have 3d. It
will therefore appear that the charge of three pies per mile to the Indian
third class passenger, is to all intents and purposes equivalent to an Eng-
lish rate of at least 1 £ d. per mile— a rate which would practically reduce
the third class traffic on an English railway to a minimum. It is true
that on the newly opened State railways, the charge has been reduced to
two pies per mile, which is not very much higher than the ordinary Eng-
lish rate of Id. But the tendency on English lines is to a much lower faro
than this. Excursion trains constantly carry passengers at $d. per mile,
and the late successful results on the Midland Bailway show, .even in a
wealthy country like England, how largely receipts may be increased by
cheap fares. It is, therefore, with amazement that I read in a late Govern-
ment report, that "the low rate on the Delhi District (1*4 pies) was
" decidedly successful in attracting traffic. During the first half of 1874,
" when the open line was confined to the section between Delhi and Re-
" waree, 635 passengers were on an average carried daily over each mile
" of line in one direction or the other. On the Agra District (where the
" rate was two pies) during the same period, the average number was
" 250, and although this District was differently circumstanced as regards
" trade, and the distribution of the population, still there seemed to be
" much in favor of the low fares. These fares however were not sufficient
" to make the railway pay and passengers were under them carried at a
" minimum of profit, if not actually at a loss. It woe therefore decided
u that they should he raised." A step which was of course followed im-
mediately by a considerable diminution of traffic.

* Third clan traffic la alone considered here, because that forma more than —the of the whole.

t Taking the average wage of the common laborer in the two countries <3| aa. s gfd and to.)
which eeemi a fair rtenderd of compariaon, it will beeeenthatetol la nearer the mark.

16 INDIAN RAILWAY TRAFFIC.

Whoever wrote the above report, would do well to read the following : —

" It is a remarkable fact that those Companies which charge the high-
" est fares generally pay the smallest dividends. Take for instance the
" case of the Great Eastern Company, so celebrated for high fares and
" low dividends, or more strictly speaking no dividends. As a view of
" the other side of the question, take the case of the North Eastern which
" has the lowest fares and highest dividend of any large English Rail-
" way." [Fortnightly Review, July 1875].

It should be remembered that passengers consist — 1st, of those who must
travel (unless the cost be altogether prohibitary) ; 2ndly, of those who will
travel tf they can afford it — not otherwise — and that the number of these
latter greatly exceeds the former. It is obvious that if Hailway fares are
regulated simply with an eye to the former class, they will be made as
high as possible ; if the latter class are to be considered, then the ten-
dency will certainly be to lower them to a minimum, based on a careful
calculation of the lowest* profit at which the individual passenger can be
carried. Even if the net result to the Railway were the same in either
case, it is obvious that the convenience to the public is a strong element
in the comparison.

One very absurd argument which has been more than once adduced in
justification of the high fares in Indian lines may just be noticed. It is
said that, as the skilled labor and material 'employed in the construction
of these lines has to be imported from England, of course higher rates
have to be charged to passengers. Would any one in England, who
wished to travel (say) from London to Liverpool by the Great Western,
be persuaded to pay a higher fare to go by this line on the ground that it
had cost more to make it than the North Western line ? He would, of
course, travel by whichever line would carry him cheapest, and if there were
only one line, the question of his travelling or not would clearly be decided
by him on grounds quite irrespective of the cost of the line. In fact, it is
clear that such an argument rests on the folly I have hinted at above, of
regulating fares by the necessities of the few, rather than the convenience
of the many. >

II. I proceed now to notice the second obstacle to traffic — the want
of facilities for the convenience of passengers.

Some of these have been lately commented on in a recent Government

• This has been computed on good authority in England to be 80 miles for Id.— what it may be
in India I do not know.

INDIAN RAILWAY TRAFFIC. 17

resolution — they concern various minor points, all useful enough and
important in their way, which need not be further adverted to here. The
thief obstacle of all under this head is undoubtedly the trouble of procur-
ing the ticket. Any one who has seen the pushing and struggling that
take place at the ticket office of any large Railway Station in India be-
fore the starting of a train, will perfectly understand why no native, as a
role, will travel any oftener than he is obliged to do* This point has
been over and over again pointed out — the remedy for it is sufficiently
obvious to every sensible man. Yet it is not applied. Why? The only
possible answer is, that the English mind is essentially apt to run in a
groove — if you like, on a rail— and that it is very difficult to get it out
of the one or off the other. Suppose the strictly parallel case that has
been often adduced — that you could only buy postage stamps, to put on
your letters, just before the mail went out, and at one inconvenient little
pigeon hole amongst a pushing, struggling, crowd. And, as the cases are
absolutely analagous, so the remedy for one is clearly the remedy for the
other. Let ticket offices be multiplied— let them exist at every post
office— or treasury— or respectable Bunyah's shop if you will — and let them
be bought a week, or a month, or a year beforehand, if you like. In the
United States, there is a ticket office in the hall of every large hotel,
besides other offices in various parts of every large town, where you can
bay tickets for any journey you want to make, at any time, over any line*
And here again, in the case at least of the Indian State Railways, we
hare special facilities for carrying the postage stamp analogy still further,
by making railway tickets altogether general — one step towards which has
already been taken by adopting the distance between two stations as a
unit — an obvious improvement over a mileage rate. Why then should
not railway tickets of different colors represent fixed sums for so many
miles or station distances — to be travelled by the purchasers at any time
over any line in the country ? and which could be bought like stamps
at any post office ? The only objection I have heard made is, that they
might be forged — to which the natural reply is, so might stamps and cur-
rency notes. The fact is that the convenience of the arrangement would
be so great, and its advantages over the present system so immense, that
the ordinary Railway mind, accustomed to pigeon holes, stamping little
checks, dispensing change, and to the general discomfort, squabbling and
confusion of the present method, simply cannot take it in, and refuses to

VOL. V. — SECOND 8KRIE8. D

HTDIAN RAILWAY TRAFFIC.

believe that there is nothing in the nature of things to prevent a passenger
stepping as quietly into his carriage, as a letter sliding into a letter box.
If there is anything worse than the passenger ticket arrangements, it is
assuredly that for the luggage. A native clerk with an imperfect know-
ledge of English, produces a huge book, in which, after an abstruse arith-
metical calculation, he slowly writes down an amount of information about
the passenger and his traps, which is of no conceivable use to any one
under the sun.

On American lines, if luggage is paid for at all, it is charged by the
piece-** numbered label is strapped on to each piece, a duplicate handed
to the owner and the transaction ends. But would you charge for a sea
chest the same price as for a hand bag ? the answer to which is, that
people don't travel about with sea chests, and if they do, they would have
to be left behind. In this, as in all similar cases, rules should be framed
to suit the average traveller with an average amount of common sense-
not with a view of including all possible exceptions, and of incommoding
ninety-nine passengers to avoid being cheated by the hundredth.

It cannot be too strongly pointed out that a Railway, if it is to be made
to pay, should be looked upon as a shop, and conducted on the principle
of attracting customers. If I want to make a profit by my wares, I do
all I can to advertize my goods, and to entice people to buy (even when
they have no idea of buying) by civility and even blandishments. Does an
Indian Railway present this aspect, especially to a third class passenger ?
I trow not. From the moment he enters its precincts, he is virtually
a prisoner and a slave, while if he has any idea of employing the line to
carry goods for him, he is frightened by the perusal of a string of bye-
laws apparently drawn up* to screen the Railway Company from any re-
sponsibility in the matter, and of impressing him with the idea that he
ought to be very much obliged to the Railway for condescending to carry
him or his goods at all.

It is obvious that such a system is altogether wrong — every pains should
be taken to attract travellers by low fares, comfortable carriages, conve-
nient stations, suitable means of refreshment, and civility and protection
from imposition. It is not enough, if the people won't travel in sufficient

* Suppose yon were met at the entrance of a shop by the Proprietor who told yon " Sir ! I warn
yon before yon enter my shop, that I will not be responsible, if any of the goods are damaged— or if
your pockets are picked— or if any mistake is made in giving yon change— or if yon are subject to
«ny other inconvenience, loss or damage." Yet this Is very much the principle on which Railway!
act with regard to their customers.

INDIAN RAILWAY TRAFFIC. 19

numbers, to sit down contented and say, it is their own fanlt. It shonld
be ascertained why they won't travel, and additional inducements shonld
be offered. So in the case of goods — if the Railway wants to carry goods,
it shonld tout for them — smooth all difficulties in the way of reception and
delivery, and if they won't come to the Railway from a distant town, go
to that town and fetch them.

With regard to the above item of " comfortable carriages," it is strange
that the greater convenience of the American cars, especially in such a
climate as this and for long journeys, has not yet been recognized. They
possess greater facilities for ventilating and cooling, they enable the pas-
sengers to move abont at will from carriage to carriage while the train is
in motion, and by enabling the conductor or guard to pass from end to end
of the train, they facilitate the taking of tickets, the giving of informa-
tion to passengers, and that general supervision which is important in
the case of native passengers, and which can now not be exercised, except
when the train is at rest. They also enable conveniences to be provided
for the supply of natural wants and bodily refreshment in a manner which
is now only accomplished by undue detention at stations.

To sum up what has been above argued — it is suggested that, in order
to develop© the Railway traffic in this country properly, and so as to
make Railways pay — it is necessary —

1st. To reduce third class passenger fares — looking upon a rate of two
pies per mile as a maximum, and which, following the experience of the
most successful English lines, should be reduced to one pie.

2mf. To facilitate the comfort and convenience of travellers, (a). By
multiplying the number of ticket offices, and making tickets procurable as
*&eily as postage stamps, (b). By charging for luggage by the piece, and
doing away with all booking and weighing, (c). By 'adopting the American
1 form of carriage, by which greater comfort and convenience will be

enjoyed by the passenger, and delays will be obviated at stations other
than what is necessary for taking up and setting down. (d). By establish-
ing Booking Offices at all towns within reach of the line, where delivery
<*a be taken of goods to be conveyed, instead of waiting for the goods to
come to the rail. (t). By impressing on all Railway employe's, from the
highest to the lowest, that it is their fault if the people don't travel I
I invite discussion on all these points.

J. G. M.

ELHIR

20 PROTECTION OP PIERS OF LARGE BRIDGES ON THE 8. P. & D. RAILWAY.

No. CLXXXIII.

PROTECTION OP PIERS OP LARGE BRIDGES ON THE ««•*
SCINDE, PUNJAB AND DELHI RAILWAY.

[Vide Plates V., VL, VIL VUL and IX]

vNln

The three important bridges on the Scinde, Punjab and Delhi Railway are
those over the Jumna, Sutlej, and Beas Rivers. They are all of the same p
type, being formed of double triangulated girders in 100-feet spans in
the clear ; the railway passing above the girders, which are supported on
single cylindrical piers 12 feet 6 inches in external diameter, and sunk to
an average depth of 40 feet below low- water level.

The Jumna bridge consists of 24 such spans.
„ Sutlej „ „ 59 „

„ J5eas ,, „ o* „

The Railway was opened for traffic throughout in the year 1870.

During the floods of 1871, the fall of several of the piers which had
been exposed to severe scour rendered it necessary to take precautionary
measures to arrest further destruction of these cylinders. f

The method adopted has been that of depositing masses of loose stone,
blocks of brickwork, or kunkur, round the piers ; and this plan has so far
been attended with satisfactory results.

The comparative sections of the Sutlej, taken before and after the de- \

position of stone, show that the tendency of the stone protection is to
- deflect the scour from the vicinity of the piers, whereas, previously, the
tendency of the current was to hug the piers and undermine them. At
the west abutment of the Beas, it has been found that the stone thrown in
to protect the long splayed wing-walls, after having been exposed to a
very severe rush of water, took a slope of from 1 J to 2 to 1 after the first
floods, and has not since moved.

PLATE V.

ELHI RAILWAY.

Koti.

B*4%f«

»•

tybr* 4*po9it of&kmt

£ & £ SMMMTKAil

PLATE VI

IA1LWAY.

■•■

ng put im dmee Fl—d*.

PROTECTION OF PIKES OF LARGE BRIDGES ON THE 8. P. & D. RAILWAY. 21

The accompanying sections (Plates V. and VI.) give a fair sample of the
form which the stone placed round piers has assumed, after being subject
to heavy scour in the main channels. The quantity of stone placed round
each pier has varied much, as many of the piers have not been exposed to
the most severe scour that may at some future time come upon them with
variations in the channels of these rivers ; but it is estimated that an
average of 20,000 feet of stone per pier will suffice. A large supply of
stone is kept in reserve at each bridge, and the piers will require constant
attention and watchfulness for many years to come. It will be observed
that, in some of the latter sections, the stone is higher than in the earlier
sections, this is accounted for by additions of stone made from time to time.

During the floods, soundings are taken three times a day at the piers
exposed to scour, and any settlement below 12 feet from high-flood level
is at once made up to that depth by throwing in stone.

A somewhat unaccountable case has been observed at the Sutlej Bridge
in pier No. 53, which sank two inches after the silting up of the channel,
at a lime when there was no water at the surface. A similar case has
been observed at the Markunda Bridge in one of the piers, which sank
two inches shortly after the opening for traffic ; and, though it is protected
by 5,000 cubic feet of stone and sand for 40 feet of its depth, it has
since settled three inches more.

Jumna Bridge. — The accompanying plan {Plate VII.) shows the
several features of the Jumna Bridge and its protective works.

During the floods, the land for a considerable distance beyond the
banks of the river, is covered with water, which, when the floods subside,
flows parallel to the embankments ; and, to avoid the damage which would
otherwise ensue, the embankments are protected for a considerable dis-
tance with stone, trenched in to low-water level, about 10 feet wide, and
up the slope, to above high-water level. Groynes have been thrown out
to keep the river to its course. They are composed of earth and sand
faced with stone and sloped towards the river. In 1872 they had a very
heavy body of water against them, the hearting was washed out in some
places causing them to settle, but the settlement was made good with
stone. Each season the settlement has been less, and, although during
last season, the scour was as deep as 28 feet on the face, and 87 feet near
the nose of the groyne, no permanent injury was done.

The material used for the protection of the piers was block kunkur,

22 PROTECTION OF PIER8 OF LAROE BRIDGES ON THE 8. P. & D. RAILWAY.

obtained from quarries about 5 miles north of Sirsawa Station. The
earth and foreign substances in the interstices of the kunknr were found
to wash out and fill in the spaces between the blocks, so that it became a
solid mass only to be removed by crow-bars.

The quantity of stone used round the piers varies from 87,000 to
2,600 cubic feet. The average round each pier is about 15,600 feet.
The total quantity deposited is as follows : —

Bound 23 piers, •• •• •• •• 858,660

East abutment and berm, .. •• •• 450,000

West ditto, .. .. .. .. 220,500

Toe of east bank, . . .. .. •• 49,000

„ west „ .. •• •• •• 74,000

Main bond, . • . . • • • • • • 1,059,525

Lower „ .. . . .. •• •• 825,000

Total, . . 2,536,685

Sutlej Bridge.— The principal features of the Sutlej bridge and its
protective works, are shown in the accompanying plan (Plate VIII.)

The effective waterway of the bridge is from pier 1 to pier 49. The
remaining spans are closed with a bank faced with stone rising two feet
above highest flood level ; from 49 to 50 for two seasons a powerful cur-
rent has set against this bank, which however has not been affected by it.
The water, after meeting the obstacle, flowed along its face, and then
swirled round the end with great velocity through spans 46 and 47,
causing a scour to the depth of about 40 feet between the piers, but in no
way affecting the stone round the piers, beyond causing settlement. An
the floods subsided, the space scoured out silted up, and a flooring of loose
stone was laid on the silt between the piers.

The two small irregular bunds (marked 1 and 2 on plan) were originally
formed of earthwork and brushwood by the contractors, but were subse-
quently repaired and faced with stone by the Company. The long upper
bund has also been faced with stone, and extended about 600 feet into the
river, the end being sloped out and formed entirely of stone. The effect
of the latter has been to throw the channel further over, and to relieve the
strong rush along the stone revetment from pier 49 to 53, and, gradually,,
to silt up the bay below the nose of the spur.

Piers 1 to 49 have had stone deposited around them, varying in quan-
tity from 43,500 to 8,200 cubic feet The quantity of scour around these

plate rm.

PROTECTION OF PIEB8 OF LARGE BRIDGES ON THE 8. P. & D. RAILWAY. 23

piers averages 16,774 cubic feet. The total quantity of stone deposited
is as follows : —

At the piers 1 to 49, •• •• .. .. 826,953

Flooring and other protection, •• .. .. 274,940

Phillonr abutment, .. .. .. .. 83,983

Protecting bunds, .. ... .. .. 1,218,719

Total, . . 2,404,595

>- — The accompanying plan (Plate IX.) shows the general

features of the Beas Bridge and its protective works. The west bank of

the river is high ground, but on the east bank the water spreads itself in

floods. The two end spans 1 and 2 and b3 and 34 are floored with loose

stone, and, from this latter flooring, springs the east abutment, from

which runs a long bund 4,500 feet in length, which was constructed by

digging a trench 20 feet wide and 10 feet deep. The earth was thrown

back to high flood level and then faced and topped with stone, the toe of

the slope towards the river face being composed wholly of stone. At

A is a depression or causeway to allow the flood water to drain off when

the floods subside. The land end is well trenched with solid stone, and

the small cross bund connects the main bund with the embankment as an

additional protection to the abutment.

The stone round each pier varies from 30,366 to 1,240 cubic feet. The

quantity of stone round the 33 piers averages 13,248 cubic feet. The total

quantity deposited is as follows :— •

Bound the piers, . • • . • • . . 472,773

East abutment, . • .. . . •• .. 141,387

West, „ .. •• .. .. .. 201,900

Bonds, •• •• •• •• •• 700,771

^__ ^_ __^

Total, .. 1,516,831

THE USE OF CONCRETE IN INDIA.

No. CLXXXIV.

THE USE OP CONCRETE IN INDIA.

By Fitzhugh Cox, Esq., Assist. Engineer, P. W. Department.

8Mhot, November 1875.

The use of concrete to any extent in this country is very recent, and
though this material is being daily more widely applied, it most be ad-
mitted that the use of concrete in India is yet in its infancy.

At present it is not much used beyond the requirements of bridge and
building foundation, and there is an evident distrust and dislike shown
to its application, as the only material for bridges, roofs, walls of buildings,
cylinders of wells, and in fact to anything where stone masonry or brick-
work has been hitherto exclusively used. The argument usually adduced
against the more extended use of concrete work is the difficulty in this
country of securing the strict supervision which nrast be exercised over
monolithic works, to ensure that the native agency employed mix the
materials in the proportions ordered — that they ram the material equally
— that they do not put too much water — and that they keep it thoroughly
wet for some time after the completion of the work. There are other
difficulties too in the way of establishment, &c, as cften a District En-
gineer has to perform a small piece of work of this description only once
now and then, and finds it easier to ensure good work by estimating for
brickwork, than running the chance of failure with an untried, or not
thoroughly competent, superintendent on the spot.

In this short Article, I do not pretend to show all that has been, or may
be done, but I would raise a voice in favor of the use of this most useful
material in a more extended form than hitherto. My experience in this
mode of building is not sufficient to constitute me a special authority on

THE USB OF CONCRETE IN INDIA. 25

the subject, but such experience as I have had, may entitle my opinion
to some weight in regard to the use of concrete in the localities (in the
Punjab) in which I have been employed ; and my object will be served
if I can draw increased attention to this material, and can influence
others to devote their energies to developing this most useful form of
construction, which is eminently adapted to a country where stone is
scarce and expensive.

Materials. — The first thing to be considered is the material. In the
Plains the most abundant material as a rale is broken brick, kunkur lime,
or stone lime and surkf.

For moderate sized works, there is generally a sufficiency of the former
material available, but in new work, where a large amount of concrete has
to be laid down as foundations, the ' broken brick ' will have to be ex-
pressly made.

♦ Stone. — This material if it can be obtained is superior to brick for con-
crete purposes, but it is not often that it is procurable at reasonable rates ;
and broken stone again requires to be broken quarry-stone with sharp
rectangular edges, and not merely broken pebbles, such as those found
in the lower hill ranges : the stone should be any hard sort procurable,
care being taken that the soft grey sandstone which is very common is
not mixed with it.

Brick. — Next in order of quality is broken brick, or more properly bal-
last, as the moulded brick is superior to the broken brick properly so
called. Moulding brick ballast is extremely simple. It consists merely
of spreading slabs of well tempered mud over a sanded floor, the slabs
are smoothed down by hand with a little water to the required thickness
one inch, and when somewhat dry, cut with a knife into one inch squares.
By merely running a spade under them, the ballast is broken up, and
ready for burning in oopla kilns.

Kunkur. — Next in order come kunkur nodules. If block kunkur of
a hard blue kind is procurable, it would rank before broken brick, but the
ordinary kunkur as a rule is not always reliable, and has other objections.
In the first place it is more expensive, it has to be washed, the whole of
the mud is not easily cleaned off, it catches mud and dust more easily
than broken brick, and lastly, it is more easily broken in ramming.

The size of the aggregate, (as it is called,) should be cubes which will
pass through a one-and-a-half inch ring for thick work, and through a

VOL. V.— SECOND SERIES. B

26 THE UBS OF CONCRETE IN INDIA.

one inch ring for fine work. Some Engineers prefer to use smaller ag-
gregates, and others larger ; the latter is the lesser mistake of the two, as
far as strength goes, hut it uses more of the expensive material, viz., mor-
tar. After a good many trials, I have come to the conclusion that the
above sizes are the most suited.

The amount of mortar required should be just such an amount as will
fill the spaces between each piece and no more : as this in practice is rather
difficult, it is usual to add from five to ten per cent, excess. The voids in
the ballast can easily be ascertained, by filling a (cubic foot) box with
well saturated ballast, and then pouring in water from a measured vessel,
or by shaking sand into a similar box filled with dry ballast. The smaller
the size of the aggregate, the smaller will be the quantity of the mortar
used ; for the above sizes, I have found 85 to 45 cubic feet of mortar
(dry) to be sufficient, but I have heard of as much as 50 to 60 cubic feet
per cent, being used ; my experience tends to show that this is a mistake
and a waste of material. Oillmore in his work on " Limes, Hydraulic
Cements and Mortars," Chapter VII., para. 440, says — "As lime or
cement is the cementing substance in mortar, so mortar itself occupies
a similar relation to concrete or beton. Its proportion should be deter-
mined in accordance with the principle, that the volume of the cementing
substance should always be somewhat in excess of the volume of voids
in the coarse materials to be united. The excess is added as a precaution
against imperfect manipulation.9*

As this is more necessary in India, a rather larger percentage is allowed,
and the proportions should therefore be regulated by the following :—

\sU By the size to which the aggregate is broken, determined by ac-
tual experiment.

2nd. By the amount of skilled supervision which can be given to the
work.

Composition of Mortar.— The mortar may be composed of lime, either
fat or slightly hydraulic, kunkur lime or kunkur cements. With fat
lime, some sort of puzzolana must be used, and good coarse sand may or
may not be used at discretion of Engineer. The puzzolana in common
is 8iirki, and* a good deal of diversity of opinion on the subject, viz.,
whether thoroughly burnt bricks and refuse, or whether underburnt brick
&c, should be converted into puzzolana. As a rule, I believe the thor-

• Vide Article No. CLXXXI., by Mr. Dejonx on the fubject.

THB USB OF CONCBBTB IN IHDIA,

oughly burnt brick advocates carry the day ; one reason being, that it is
very difficult to point out to a native workman the particular amount
©f « underdonenese' allowed, and still more to make him stick to that sort,
as the more easily a brick is broken, the more he can do in a day, and,
therefore, he chooses the softest possible.

Pucka surlrf then being used, should be of such a size as to pass readily
through a No. 8 wire gauze screen.

Lime Slaking.— The lime should be brought to works unslaked, and to
fit it for use, it must be slaked. Now to this subject of slaking very little
attention is paid as a rule. There are three methods which Gillmore in
his treatise above alluded to treats so fully, that to those who wish to
study the subject more in detail, I would recommend them to read Chapter
VL, paras. 817-841. I will merely here endeavour to show the best
and easiest away, and wherein lies the defect of the usual native method.

The best way to slake lime is to lay it out on a platform of bricks in
a layer not more than six inches in depth, and surrounded by a raised
aide of bricks backed with earth forming a shallow basin. On this
should be poured at once the quantity of water necessary to slake the
mass, which will vary from 2£ to 3 times the volume of the quick lime.
After which it should be left undisturbed until required for use, which
should be not before the end of the third day from that on which the lime
was slaked. If it can be covered for that time so much the better.

Most slaked lime will be found (unless slaked as above) to be full of
small lumps about the size of a pea, or even larger; the reason of this
is, the lime during slaking has been suddenly chilled ; the bheestie brings
a skin full of water, (perhaps not a tenth part of what is necessary for
the amount of lime spread out,) he throws this on, and then goes lei-
surely away to bring more, taking perhaps ten minutes to bring another ;
lie arrives just as the lime is beginning to expand, and then he throws on
in like manner the second skin- full ; as a rule he puts too little even when
the operation is completed, and this is a constant source of expansion in
work and cracking in plaster, besides having a good deal of the useful
energy of the granulated lime literally thrown away as the puzzolana
(BTirki) cannot amalgamate so readily with the granular lime, as it will
with the powdered lime.

The fat lime* can be used as a general rule with proportion of 1 part
to 2 parts of siirki, well mixed in a dry state.

28 THE U8B OF OOHCBBTB IV IHDIA.

Slightly hydraulic limes do not take so much water to slake, neither
should they be used so long after slaking ; as a general rale, the more hy-
draulic a lime, the sooner it should be used. Sdrki too can only be need
in a lesser proportion, varying with the amount of impurities which they
contain, and which vary from *10 to "20 of the whole.

Kunkur lime or kunkur cement ; I consider the latter the proper term
for this material, or at any rate for such as contains anything between
45 and 55 per cent, carbonate of lime.

Mr. Noilly, in a paper in one of the former numbers of the Roorkee
Professional Papers, dated 17th October, 1872, para. 18, says, " The true
appellation of cements is claimed for many of the burnt kunknrs :" an
opinion in which I fully concur, and in fact consider that as a general rule,
kunkur lime should not only be considered a cement, but treated as audi.

I may note en passant that the method of burning which I found moat
satisfactory was to burn kunkur cement in open clamps with charcoal.
I never heard of its introduction any where else until I had it in uee for
about one year. I first laid a layer of oopla on the ground, kept in by a
ring of bricks with three or four fire holes running from the centre oat*
wards, in order to start the fire evenly. The charcoal being first measured
in boxes, was laid on the heaps of kunkur (broken small) in the proportion
of 40 feet of charcoal to 100 cubic feet of kunkur, or about 10 maunds of
the former. The kunkur and charcoal were then shovelled into baskets,
which were emptied on to the oopla with a rotary motion, spreading the
kunkur evenly and mixing it most effectually, this went on until a conical
heap was formed containing about 2,000 cubic feet of kunkur, the most
useful size. The outside had then a course of bricks laid on, and waa
carefully plastered over. The kiln was lighted from the bottom, and
allowed to burn itself out. Should the fire break out in one spot too
fiercely, it was easily damped down with fresh mud. The outturns were
found very satisfactory on the whole, and with less overbornt kunkur and
cinder than in the common Y-shaped kilns.

The kunkur cement should be pounded so as to pass through No 8
wire gauze mesh. It should be mixed only a little while before use, and
used with as little water as possible.

In mixing the aggregate with the matrix or mortar the best
way is to mix the fat lime and surkf together, first dry, and then to lay it
on the aggregate, which has been previously wetted in the proper propor~

TBB USB OF CONCERT* 15 INDIA. 29

tions; the aggregate below in a layer not more than 4} inches thick, then
the matrix, then another layer of aggregate, and then the matrix. The
whole should then be slightly wetted by means of a watering pot and
thoroughly turned over. I found two men digging with forks working
backwards and forwards, and two turning over from right to left, sufficient
to mix the whole well ; the material being watered the whole time— -by
this means, a proper supply of water in finely divided streams was supplied
to the mortar, and with proper attention no difficulty was experienced after
the men had become accustomed to the work. The operation is one how-
ever which requires constant skilled supervision, as though the matter is
an apparently easy one, it is not so in actual practice. Gillmore quoting
from a report by Lieut. Wright on the Fortifications of Boston Harbour
says, para. 450, " The success of the operation depends entirely upon the
proper management of the hoe and shovel, and though this may be easily
learned by the laborer, yet he seldom acquires it without the particular
attention of the overseer."

I tried a machine for mixing, which was a much slower and more ex-
pensive process, and the results were, if anything, rather worse than hand
labor, as all the aggregates fell or rolled to the sides of the heaps, while
the mortar remained in the middle. This machine was an upright box
about 12 feet in height and 8 feet square in section, containing shelves
at an oblique angle; the material on being thrown in was dropped from one
shelf to another until it reached the base, where it found an exit at a
small door. The object was to thoroughly incorporate the aggregate in
the matrix, but as before said, the results were not satisfactory.

Bamming Concrete. — The material when mixed should be carried
away, and carefully placed in the trenches or boxes in which it must be
rammed, first at the sides, and then in the middle, until it is firm and com-
pact. If too much water has been poured on, the whole mass becomes a
shaking jelly, the tendency of which is to drop the heavier particles to the
bottom, the lime and finer portions of surkf rising to the top. If after a
slight ramming this is found to be the case, the only remedy is to cease
ramming, allow the water to settle for half an hour or so, and then to take
up the material and relay it. The test of the proper quantity of water, is
to take a small quantity of concrete in the hand, and after giving it a
moderate squeeze with the thumb and finger, it should easily fall in a cake,
leaving scarcely a soil on the finger. Too small a quantity of water can

80 THE USB 09 CONCRETE IN INDIA.

easily be remedied by merely watering the material after each ramming,
which should bring the water again to the surface the next time in the
form of dew-like drops.

Between each successive ramming, the face should be picked up with a
sharp pick, otherwise the lime will form a thin film between each coarse,
and effectually prevent any adhesion between the two.

Sand. — In my experience I have found that as a rule sand is not avail*
able; at least sand of such a quality as to make it a desirable ingredient
in mortar : where it can be obtained it w a very desirable one, and should
be used in equal proportions with surkf. It should be clean, sharp,
coarse grained sand and free from mica.

It is not easy in an Article of this description, to fix the proportions for
mortar, via., for the lime, surkf, or sand, as that depends entirely on the
quality of the former, and these proportions must be different in different
localities with their varying qualities and sorts of materials.

A great addition to the strength of the concrete is made by mixing
about 20 per cent, of fine aggegates with the coarse ; they may be cleaned
road scrapings consisting of washed kunkur, or of coarse surki screenings
or fine gravel ; these help to fill the voids and do not leave such a number
to be filled by the mortar.

Concrete should be kept damp as long as possible, especially in
such a climate as India, for two months in the hot weather, and should
when new be protected from the frost.

The former part of this Article has treated generally of concrete, and
more particularly as applicable to course work, such as foundations, where
the only points of attention worth special care are, the thorough incor-
poration of the materials, and the proper ramming of the whole, so as to
insure a solid, compact, and non-porous maBS. But concrete is appli-
cable to every use to which brickwork can be applied, and I will now
endeavour to show some of these uses, to which it can be in India applied.

In the year 1830, an architect, M. Lebrun, built himself a house on his
estate at Alby (Department du Yarn) entirely of beton. The beton was
composed of one part hydraulic lime, one part clean sand, and two parts
shingle, averaging one inch in suae. The (aces of the walls were plastered
with sifted sand and mortar. The building appears to have been most
successful, and its cost was about one-half what it wouM have been had
it been built of brickwork.

THE U8E OF CONCRETE IN INDIA*

The term beton is often restricted to concrete whose matrix is hydraulio
lime or cement, whereas concrete is the term applied to a composition
of fat lime and puzzolana. The words concrete and b&ton, although
originally by no means synonymous, have become almost so by use ; con-
crete being the term most used, whereas the matrix in Europe is more
generally hydraulio lime or cement, than common lime.

In the construction of buildings, there are two methods in use— 1st,
the monolithic; and 2nd, the block system.

Monolithic concrete. — The monolithic, provided sufficient skilled su-
pervision has been given to the building, during its construction, makes the
more solid erection, but the block system has this advantage, that by
reason of the small size comparatively of each block, all danger on ac-
count of bad workmanship is put out of the question, even though a bad
block may go in now and then, those above, below, and around it protect
that portion from collapse, whilst it at the same time offers additional
facilities for the prevention of the introduction of bad work into the erec-
tion. It allows of a greater variety of detail of ornament, and avoids any
unsightly bulge in the wall due to the defect in setting up any particular
box, or case.

In the monolithic method, the concrete is placed in boxes formed of
stout boards, end of any convenient length, tied together by horizontal irons
above or below ; the latter are pierced with holes both to suit alteration in
width of wall, and also to assist their extraction on removal of the case
when one set have been filled and consolidated.

In the margin there is a sketch showing a
device by Mr. E. E. Clarke, for the erection of
monolithic concrete houses. The following is
Qillmore's description of its use : — " It consists
essentially of a wooden clamp, the vertical
parallel arms of which can readily be adjusted
by means of traverse screws to any required
thickness of wall.

"These arms support the planking which
determine the thickness of the wall, and are
attached— one fixed and one movable— to a
horizontal brace. When in use, the entire
apparatus is kept in position by securing this brace to some fixed point of

32 THE USB OF CONCRETE IN INDIA.

support. In carrying np the walls of a building, these points of support
are provided on the inside, being vertical posts secured to the ground, in
the first instance by braces, and afterward to the flooring joists of the
upper stories."

The arches over doors, windows and other small openings, may be ram-
med up solid in horizontal layers, greater pains being taken to make
them thoroughly homogeneous, but the arches of the larger openings, such
as verandah arches, should be rammed in -6* or 8* courses, radiating to-
wards the centre; unless their thickness is considerable, it is better to
build the arches of blocks thoroughly hardened, which have been made
to suit the radius, &c, required.

The roof. — The roof may be made of a very light semi-circular half
arch with a few tie-rods for the verandah roofs, and a semi-cylindrical
roof for the main rooms. The roof should be beton of very .fine material,
carefully consolidated, and when about half dry, rendered with Portland
cement and knnkur cement in the proportions of 1 to 2, to close up
any hair cracks which might have shown themselves, and also to prevent
as far as possible the growth of vegetable matter, and to facilitate the
passing off of water during rain. With this exception, the whole of such
a building might be made of concrete, at a cost of not more than two-
thirds the amount a similar construction of brick would cost. It is hardly
necessary to say that all the arching centres must be of timber.

Concrete Blocks. — In the block system, the building is constructed
of blocks carefully rammed in boxes or nests of boxes containing four to
twelve blocks each. The material is of two sorts, fine and coarse, a small
quantity of fine being laid on the side to form the outer face of the block,
the body is made up of coarse, the whole being rammed together. The
cases had better be left on for one day and removed the next, and allowed
to dry in the air under shade for a week, when they should be placed
in a tank of water to indurate for six weeks to two months ; at the end
of that time, they may be taken out and dried under cover.

In this way cornice bricks, moulding bricks, and patterns may be
moulded with good sharp edges, and not only so, but the tints can be
varied by dusting the nearly dry outer surface with red brick dust, grey
kunkur cement, black vitrified brick dust, or any other coloring material
obtainable. This would greatly enhance the appearance of a building in
which color formed a part of the design.

THB USB OF COKORETE IV INDIA. 88

The blocks for ordinary building purposes should be in any sizes, suit-
able to the construction required. Common blocks should be in the pro-
portion of half breadth to length and one-third thickness. For instance,
if it were proposed to build an 18-inch wall of block concrete, they
might be 18 inches long 9 inches wide and 6 inches thick, or 8 feet long
38 inches wide and 9 to 12 inches thick : the former would be the mora
useful size for a height of over 5 feet, as the latter would require tackle to
put them in position, whilst the former might be done by hand labor.

Such blocks might be made with a sunk joint ^-inch depth, this would
add greatly to the ornamental appearance of a building, and cost nothing
beyond the nominal first cost of the mould.

Plain work, such as is usually put into Government buildings, could
be done in concrete for the same cost as kncha pucka brickwork, (viz.,
burnt bricks in mud mortar,) with pointing on the external face : nay
more, — in works where a good deal of brickwork is going on, and where
the moulds required would be used for several buildings, and where a
suitable aggregate can be obtained at a moderate cost, — I consider that
concrete could satisfactorily compete with that cheap, but not too good,
substitute for pucka brickwork. With block concrete, hollow walls could
be easily constructed, each block having either a hollow in its centre, or
a nick cut out of the ends, similar to the hollow brick system.

Block concrete would form a very neat addition to a building, as round
windows, and doors, or at the corners of buildings, and with any light
colored mortar, it would have the appearance of bath stone, dressings.
When placed under woodwork and over burnt brick and mud mortar ma-
sonry, it serves the two-fold purpose of wall plates and protection from
white ants.

The principal drawbacks to the use of block concrete is the system of
the P. W. Department : buildings have to be built in a very short time,
and proper time cannot be given in their manufacture before the time they
are required for use : as often sanctioned buildings are not put in hand
until but a short period before the end of official year, and block concrete
requires not only careful supervision, but also time to season the blocks.
The best season is during the rains, as then they get a gradual drying,
and also get fairly hard before the cold weather and frost.

Flooring. — If concrete were made of Portland cement, and over-burnt
brick broken to the size of a pea, I believe it would form a very excel-

VOL. V. — SECOND SERIES. F

84 THE USB OF CONCRETE IN INDIA.

lent and lasting flooring, easily laid, and not likely to get out of order.
A pavement was made for the footway of King William Street City, of
Portland cement and oolitic limestone, which lasted 14 years ; and this is
certainly longer than the life of a brick in an Indian Barrack Room.

Wells could be made of monolithic, or block concrete, at a less cost than
brickwork; in the former case, a wrought-iron cylindrical case about 15
inches deep would be necessary, but for a small work a wooden one might
be made to do duty, and a saying could be affected by diminishing the
thickness of the cylinder ; as in deep wells 9 inches would be ample for the
first 20 feet, l£ feet for the next 80 or 50. In wells 6 to 9 feet diame-
ter, blocks might be made so as to divide the circumference into 6 to 10
parts, and would then be easily handled and laid.

Tanks. — Concrete is a very useful material in the construction of tanks,
as it is quite impervious to water, i.e., if properly made, and has no joints
through which the water in brickwork so frequently finds its way.

For district bridges % Irish bridges, mile posts, (to this latter use it is
largely applied in the Irrigation Department,) encamping ground boundary
pillars, and such like work, it is especially adapted.

It has been largely used on the Northern (State) Railway bridges to
throw in round the piers, and appears to have well answered its pur-
pose. A very fair road might be made oyer some of the Indian rivers
(narrow) in which quick sands abound, by throwing in blocks of concrete
until a firm base is attained, over which the permanent road could be made.

The above are some of the uses to which it could be, or has been, ap-
plied, and I will in conclusion sum up the special points of attention to
ensure good work and workmanlike finish, combined with a fairly low cost.

1st The aggregate should be a medium size, not smaller than £-incb
cubes, nor larger than l£-inch cubes ; it should be hard, not too porous,
nor yet perfectly impermeable by water; it should not be round pebbles;
and should be fairly wet before mixing with the water, otherwise it too
rapidly absorbs the moisture of the latter, much to the detriment of the

whole.

2nd. The lime should, if fat, be thoroughly slaked, and laid with a
sufficiency of water, which should be added at once not in driblets.

fhd. The sfirki should be not less than fairly well burnt pounded
brick. The sand should be large, coarse, clean, and free from mica, or at
least tolerably so.

THE USB OF CONCRETE IN INDIA. 35

4th. The lime and surkf should he both finely sifted and thoroughly
incorporated with one another, this being one of the great secrets of good
mortar ; after haying been once made and set, mortar should not be made
over again, therefore only one day's work should be made up at a time.
The mortar should not be too wet, and it should be thoroughly turned
over until the aggregate is well incorporated with it.

hth. The concrete should be carefully laid in the trenches or boxes in
which it will be rammed in layers not exceeding 6 inches ; not allowed
slowly to roll out of a basket, or to be thrown from a height of a foot.

6fA. In ramming, the sides and corners should first be consolidated,
and then the centre, and watered now and then, as the water contained in
it becomes absorbed by the sun or earth. The ramming should .all be
done in one operation, and it should not be re-rammed after a considerable
interval, or else the " set " of the mortar is spoiled. After every course
the surface to be scraped and scratched, so as to present a rough face to
the succeeding course.

7th. Concrete should be kept damp and allowed to season as long as
possible before being used, or before any great weight is applied. It
should be protected from the sun and frost.

8th. Block concrete should not be subject to blows or shakes when
fresh ; and all concrete should be clean without any mixture of vegetable
matter, such as straw, grass, &o.

9tk. In conclusion, concrete can be used in almost any position, and for
almost every kind of work to which brickwork is applicable, at about
half to four-fifths the cost of brickwork. But it requires better supervi-
sion than brickwork, and thorough attention to details.

F. C.

P.8. — Since the foregoing went to Press, I see that " The Building News " ad-
vertises a Prize Competition for a Concrete Villa, [vide Building News of the 12th
November, 1875.] In the Notices of " Contracts open, " there are constant notices of
concrete erections of various kinds, showing that the subject is attracting, as it
ought to do, a daily increasing interest.,—

36 BTONBY'8 PATENT IMPROVED 8URKI 8CBEE9.

ML.

No. CLXXXV.
STONEY'S PATENT IMPROVED SURKI SCREEN.

[ Vide Plate X.]

By E. W. Stonby, Esq., M.LC.E.

This sfirki screen consists of a supporting frame-work of timber of the
form shown in Figs. 1, 2, 8, or any other suitable form, which frame
may, for convenience, be supported by wheels to allow of the screen being
shifted from place to place as required.

From this frame a screen W (formed of suitable materials) is suspend-
ed by wires or chains A„ A,, A„ A4 placed wider apart at top where
attached to the frame, than at bottom where they are fixed to the screen
W ; the screen is so suspended as to slope longitudinally towards the end
to which the spout S for discharging the screenings is secured.

At the middle of the screen W, and across its top, is placed a bar D,
and in this, at its centre, is an iron socket in which the crank G, driven
by the bevel wheels E, F, works.

The crank G, with its shaft H, receives rotatory motion by turning
the handle E, and thus causes the screen W to oscillate in every direction,
as shown in Figs. 1, 2, 3 and 4. Fig. 5 shows four positions of the
crank G, and the corresponding ones of the screen.

The sloping suspending rods Ap As, A,, A4 are attached by screwed
eye-bolts to the frame, in order that their lengths may be adjusted so as
to give the screen W its proper slope.

The material to be screened is poured into the hopper X, which de-
livers it to the screen W.

In consequence of the sloping position of the suspending rods A,, A,,
A, A49 Fig. 3, the screen W is tilted alternately from side to side as
the crank G rotates; Fig. 2 shows its normal central position level,

:<3&

STONKY'S PATENT IMPROVED 8DRKI 80RBEN. 87

while the blue lines in Fig. 4 show it in the position corresponding with
that of the crank G at I, fig. 5, the right side being in this position
raised and the left lowered ; the black lines show it in its opposite posi-
tion corresponding with the position of the crank at 2, Fig. 5.

It will be noticed that the rotatory motion of the crank 6, combined
with sloping suspenders Ai, A,, As, A4, causes the screen W to vibrate
or oscillate in every direction, both horizontally and vertically, as shown
in Figs. 1, 2, 3, 4, 5 ; and so the material to be screened is most
effectively shaken about in every direction, and uniformly distributed over
the surface of the screen.

The mode of using the screen is very simple: the material to be
screened is poured into the hopper X by women, or in any other convenient
manner, while the handle K is turned continuously by manual labor,
or motive power, if desired ; the fine portions which pass through the
screen are received on the floor below, while the screenings are discharged
by the spout S into the spout Y ; the machine, if desired, may be fitted
with a shoot 0 placed as shown by dotted lines on Fig. 4, so arranged
as to deliver the fine portions at the side.

Both the fine portions and screenings can be removed at pleasure in
any convenient way.

Work, Cost, £c, of Screen.

A screen such as has been described 6' 6" x 3' 6', will sift 120
paras, or about 10 cubic yards of brick powder per day of eight hours,
and the labor and cost was found at Madras to be as follows :—

Labour and cost of Sifting.

bs. a. p.

1 Man at four annas per day, ... 0 4 0

4 Women at one anna tax pie per day, ... ... 0 6 0

Total cost of sifting 10 cubic yards, ... 0 10 0
equal to a cost of one anna per cubic yard for the entire quantity put over
the screen. 120 paras before sifting will give about 90 of fine powder,
&nd 30 paras of screenings, but these quantities will vary according to
the degree of fineness of grinding.

A screen similar to that described and illustrated by Figs. 1, 2, 3,
costs, inclusive of Royalty, about Us. 100.

All parts of these machines are so simple, that they may be made by

38 STONHY's PATKHT IMPROVED 8URKI 8CREKK.

ordinary native smiths and carpenters ; they are in use on the Madras
Railway where they have been found so efficient, that the Deputy Consult-
ing Engineer for Railways recommended them for use in the D. P. Works.

They are easily worked by one man, and not liable to get out of order,
so that it is hoped their many good qualities may recommend them to
engineers engaged on large works in India.

The author, haying made numerous experiments on the manufacture of
artificial hydraulic mortar and concrete, found that most excellent results
could uniformly be obtained by mixing surki and sand with fat lime in
proper proportions.

These experiments clearly showed that in order to ensure success, it
was necessary to have the surki in a state of fine division, it having been
found that the finer it could be ground and sifted, the more regular and
energetic was its action.

The results obtained when making these experiments impressed upon
the Author the necessity and importance of having for his works a simple
and easily worked machine to produce fine surki, and lead him to work
out the screen above described.

The Chief Engineers of the Madras and South of India Railways, as
well as the Consulting Engineer for Railways, Madras, have seen these
screens in use and can testify to their efficiency.

Col. Drummond, R.E., has also seen them working.

The following is an extract from a report made by Capt. Ross Thomp-
son, R.E., Deputy Consulting Engineer for Railways, Madras.

" For sifting brick dust for the preparation of concrete for filling cy-
linders, Mr. Stoney has had a very simple and efficient machine construct-
ed in the temporary workshops at the Cheyair bridge site.

" It imitates in a most perfect manner the action of a man's arms when
giving motion to an ordinary hand sieve, and sifts large quantities of dust
rapidly with a small expenditure of labor.

" I am glad to find a good sized working model of this machine has
been procured for the model room of the Civil Engineering College, as
Public Works Officers would find it an extremely useful, cheap and effi-
cient machine on large works. "

All inquiries relative to them should be addressed to the Author,

Madras Railway, Chief Engineer's Office, Madras.

Ea W. S.
17th May, 1875.

1 CENTRAL-LADDER-RAIL * MOUNTAIN RAILWAY. 89

No. CLXXXVI.

CENTRAL-LADDER-RAIL ' MOUNTAIN RAILWAY.

[ Vide Plates XL, XII., XOI., XIV. and XV.]

Being translations from the German and French, with illustrations.
By Captain J. L. L. Morant, R.E., Assoc. Inst. C.E., and
F.R.6.8.

The following translations are offered to the readers of Indian Engineer-
ing in connection with Paper No. CLXV., which appeared at page 244 of
the IVth Volume. All Foreign weights measures and money have been
converted into their English equivalents.

Fifth Administration Report of the Rigi-Railway Company for

THE YEAR 1874.

(From the German).
[ Vide Plato XI.]

To the Shareholders of the Rigi Railway Company.
Gentlemen, — The Managing Committee of the Rigi Railway Com-
pany has the honor to lay before yon its Fifth Annual Report for 1874.

I. Relations with the authorities of the Confederation and with

those of the Cantons.

In 1874, with the approval of the Consulting Engineers of the Swiss
Railway Department, a contract was entered into for improving the Wid-
enbach stream at Yitznau. In 1870, 1873, and 1874, the Widenbach
channel having become partly closed with fallen debris, the tunnel below
the Schnurtobel river was much injured by the dammed up waters before
they were able to escape into the Lake. We have, therefore, determined
to entirely reform the bed of the stream at our own expense, so that no
injury can possibly occur to the adjoining works. We have put this mat-

40 ' cbntral-laddbr-rail ' mountain railway.

ter on a legal basis, and purpose carrying it out this autumn on a plan
drawn up by Mr. E. Mohr, the Chief Engineer of the Canton. This plan
has met with the approval of the National Confederate Railway Depart-
ment. Lastly, we mast notice in this our Annual Report, that the
plans required by Article 18 of the Swiss Railway Law hare been placed
by us in the Archives of the Confederation. These plans consist of
a complete general plan of the position of our railway with longitudinal
sections of the lines.

II. Our relations with other Railway undertakings.

As the Arth-Kulm railway is to be opened for traffic next summer we
made it known that we were prepared to make all necessary arrangements
at the junctions with the Staffel-Kulm line, and at the Kulm Station.
These points were discussed with the Managing Committee of the Arth-
Rigi Railway at several conferences, and were bronght, as we hoped they
would be, to a generally satisfactory conclusion. The Arth-Rigi Railway
Company is laying a second line of rails between Staffel and the Kulm
Station, so that each Company will, on this second line being completed,
possess a line for its own sole and special use. The Proprietress has
agreed to enlarge the grounds surrounding the Eulm Station, so that
there will be sufficient room for our day-traffic station platform, and for
our night sheds for five trains. The station will thus serve for the
administrative purposes of both railway lines, particular localities having
been assigned to each Company for the delivery of tickets and of luggage.
Each Company is to select and pay its own ticket collector, but the other
railway servants are to be chosen and paid for by both Companies in
common. The repairs to the Eulm Station are to be carried out by the
Proprietress at our common expense. Undue influence by the station
authorities and by all the railway servants in directing persons and goods
traffic is strictly prohibited at Kulm. An agreement with the Regina
Montium Company, which was in prospect last year relating to the leasing
of the traffic of the Kaltbad-Sheideck Railway, was concluded in the
current year on the terms mentioned in our last year's Report. These
are, that all our own expenses of every kind shall be paid back to us,
and that we shall share in the nett profits over 5 per cent. The sanction
of the Swiss National Assembly has been obtained to this contract, as we
mentioned before. It was in force for only a part of the current year,

'cutrai*- ladder-rail* moustaib railway. 41

because the Kaltbad and Sheideck line was not opened till July, and
then only as far as Unterstatten, a distance of 2 J miles. A Committee
for the construction of a railway from Lake Zurick to the Gottbard asked
ns on the 14th August, 1874, to take shares in their Company to the
Talne of £10,000. They at the same time explained to ua the proposed
works and contracts, and their method of raising loans. They subse-
quently communicated to us their Company's contract for the construc-
tion of a railway over the Briinig. This embraced a branch over the
Nase, alongside of the Lake of Lucerne, which would approach our
Titanau terminus. We closely examined all these proposals, but found
oar Company's statutes did not admit of our sharing in snch an under-
taking to the extent requested. For this reason we declined it. Our
relations with the United Lake of Lucerne Steamer Company, manifold
though they were, were this year also of the most agreeable kind. We
gladly trail ourselves of this opportunity to acknowledge it.

III. Traffic Management.

1. General Account. — Trains began running on the 18th of May, and
stopped doing so on the 15th of October, a period of nearly five months.
The extraordinarily mild winter enabled us to carry on a lively traffic in
goods between the end of the season of 1873 and the beginning of that
of 1874, in taking up materials for the construction of two Hotels on
Mount Rigi. One of these Hotels is on the Bigi line of Arth ; the other
on the Kaltbad- Sheideck line. The Tables appended exhibit the traffic.
The second line of rails between the Wasser Station of Freiburgen and
Kaltbad was opened to traffic on the 1st of July. It has completely
answered our expectations. But owing to the valley line trains which
communicated with the Lake steamers being occasionally detained, dis-
agreeable detentions where these lines cross could not sometimes be avoid-
ed. The thunderstorm of the 29th and 30th of July, threw landslips on
to our line in three places. This necessitated the closing of the line for
one day, viz., the 81st of July ; otherwise the traffic has been carried out
daring the whole season without interruption or accident.

2. Abstract of the trains that were run. — According to the time tables,
the following trains ran during the past season : —

From 18th of May to 1st of June daily fire trains in each direction
compared with three in 1878.

VOL. V. — BBOOHD 8KBIB8. 0

42 ' CENTRAL- LADBBK- BAIL' MOUHTAIK RAILWAY.

From let Jane to 15tb September daily eight trains in each direction
compared with four and
sometimes six in 1873.

From 15th September
to loth October daily fire
trains in each direction com-
pared with three in 1873.
| Of these trains two were

sometimes goods trains; bnt
these in the months of July
and Angnst bad regularly
to be changed to passenger
trains. Taking the whole
there were 5,597 (compared
with 3,830 in 1873) np and down trains, giving a train-mileage of
20,778 miles (compared with 15,310 in 1873). Of the above 5,597 trains
2,925 were for Passengers, giving 12,795 train miles.
2,672 „ Goods, „ 7,983 „

Total, .. 80,77ft „

Oat of the 2,672 goods trains, 83 were coupled for the transport of
longitudinal sleepers and rails.
These figures in 1873 were :—

2,669 Passenger trains, giving 11,26* train miles,
1,292 Goods „ „ 4ggg „

Total, .. 15,530 »

3. Pauenger Traffic—

Travellers in 1874, in their entirety numbered 1,04,394
1878, „ B 96,068

Or an increase in 1874, over 1873 of .. 8,882 or Sfi7 percent

Of which in 1874, np traffic 54,088 „ 6T8 „

„ 1874, down traffic, .. SO,311 „ 48'2 „

n 1873, np traffic, .. .. 49,761 „ 61'8 „

„ 1873, down traffic, .. 46,301 „ 48-2 „

The seats of the passenger carriages which were occupied were as follows : —

Up traffic, 1874, total Seats 77,232. Travellers 64,083 or 70 per cent

Down „ 1874, „ 76,740. „ 60,811 „ 651 „

Up „ 1878. „ 71,070. „ 49,761 „ 70 „

Down „ 1873, „ 70,884. „ 46.301J „ 651 „

4. Personal Luggage Traffic. — The appended Abstract Table shows
a small decrease in comparing 1874 with the former year ; whilst

5. The Quods Traffic amounted to 9,483 tons in this year, compared
with 4,309 tons in 1673. This extraordinary increase waa owing to the

'CKNTBAL-LADDER.RALL' MOUNTAIN RAILWAY. 48

construction of two Hotels on the Rigi-Kulm and Rigi-First Railways, as
well as to the construction of the Arth-Rigi and Kaltbad-Sheideck Rail-
ways. It mast, therefore, in subsequent years he expected to fall off.

6. Managing Expenses. — These amount to the following :—

In 1874. In 1873.

£ £

General Management, 1,187 734

Management of the Line, •• .. 1,461 626

Train Service, 1,131 623

Engine Service, 5,790 4,761

£9,519 £6,744

After omitting much of the above expenditure, which was obviously
caused by larger receipts entailing proportionately greater expenses in
every department of all the Railways, we still find a larger sum than usual
devoted to the wages of the employes in the current year's account. The
engines have been so completely provided with new axles, rack teeth and
cogged wheels, &c, that we do not anticipate that these expensive parts
will require anything to be done to them next year. But sixteen new
bearing wheels will probably be needed.

7. Employee* — 80 persons were regularly employed during the season,
and 74 persons were employed for occasional daily paid work as it arose,
such as tamping permanent way, &c. The daily paid works amounted to
4,498£ working days, which equals the work of about 25 men for a year,
calculating the year at 184 working days.

IV. — Total Receipts and Dividends.

As will be seen in the annexed traffic account, the total £
receipts (including £25 brought forward from the last

account) amounted to •• • 24,032

Deduct the expenses, • • 10,111

Balance remaining 13,921

Deduct— £

Interest at 5 per cent on £40,000 bond capital, . • 2,000

The usual dividends on £50,000 share capital,

at 5 per cent, 2,500 4,500

9,421
"Deduct^

1. Extra dividends to the Shareholders on

£50,000 share capital at 15 per cent, • . 7,500

2. 10 per cent fees to the Managing Council, 940 8,440

Balance to be carried forward to a new account, • • 981

i .

1 ORNTBAL-LADDBR-BAIL * MOUNTAIN EAILWAY.

, i

r
t

According to the above account the conpon due on onr shares of £4
will be 20 per cent, per share on the 15th December. After the reserve
funds had reached the amount of £8,000 according to the statutes we
did not find any further addition necessary. But we thought it necessary
to found a special reserve fund for building and renewing, which we started
with the amount of interest of the reserve fund, viz., £400.

In the name of the Managing Council of the Bigi Railway Company.

(Signed). Jost. Webhr, President.

C. Stcehelin, Secretary and Member*

Note by Translator. — The entire annual working expenses on the Rigi (a single
line) on a gradient of 1 in 5, appear from the above Report, to hare been 9*. 9d. per
train mile.

Its length is 8*84 miles, of which 1 J miles are laid with a doable line. It employed
in 1874 ten locomotives and seventeen carriages, and had np to the end of that year
cost (including every expenditure in construction and for rolling stock) £26,340 per
mile. Bat the cost of all railway work is greater in Switzerland than in England,
and as there is no patent for the Rigi in this country, there is nothing to prevent the
permanent way and locomotives being procured in the cheapest market

Accompaniments to above Report.

Table I.

Building Account of the Bigi Railway Company closed up to the 31s* of

October, 1874.

Receipts.

Balance brought over from

last account,
Received 1st instalment from

the Reserve Fond of 1873,

Sundries.
Interest from the Bank for

lo7«5~74, •• •• ••

Dividend for 1873 from 50
Regina Montium shares,

Total,

8,416

8,400

157

183

6,999

DlSBUBSBMENTa

(a). Bills paid.

1. Locomotive and Ma-

chinery manufacture
at Winterthur,

2. Manufacture of Wag-

ons at Freiburgh, • •

(ft). Building charges and
Traffic expenses.

New Buildings and Re-
freshment Buildings at
Vitznau,

Transfer of Balance to the
Account Current with the
Lucerne Bank, ..

624
140

• •

Total,

764

5,303

1 CEHTIUL- LADDER- BAIL MOOlTAtH BAILWAY.

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* C2STBAL-LADDER-RAIL ' MOUNTAIN RAILWAY.

thus seen that the two sections over the low country have the same
wwgjiTmfOT gradient. Oar reason for adopting over the mountain 1 in 12 J
aa the maximum gradient on the west side, and only 1 in 14J on the

east is, that the greater part of the traffic will travel from east to west.
Distribution of Gradients.— The whole length of the Railway from

Blndenz to Landeck is 41*889 miles, distributed as follows : —

BngllBh

Railway over the bm country t with a maximum gradient Mltoi*
of 1 in 40. From Blndenz to Klosterle, . . . . 15*460

From Saint Jacob to Landeck, • . • • • • 16715

• •

Total miles,

Mountain Railway with maximum gradients of 1 in 12ft
and of 1 in 14f. From Klosterle to Saint Jacob,

••

Grand Total miles,

82175

9*714
41*889

Table of Gradients.

Distances.

Gradient*.

Heights
above

ight
i the

Remarks.

Bladen*,

n •• ••

Dalaas,

• • •

• ••

9 •• •

Stnbcn, • • •

n •• •

St Cbrisfophe, .
n •• •
8L Jacob,

Flinch,

• • • •

Yards.

732

1 in 100

884

lin 66f

5,348

lin 50

166

Level.

4,977

lin 40

328

LeveL

3,992

lin 40

405

Level.

10,029

lin 40

850

LeveL

5,249

lin 12J

219

Level.

4,875

lin 12|

328

Level.

6,926

lin 14?

382

Lercl.

4,769

lin 44

893

LeveL

5,492

lin 44

392

Level.

5,232

lin 43

898

Level.

5,468

lin 40

874

LeveL

5,645

lin 40

875

lin 800

Yards.

611*5

6188

632*0

739-2

7392

838*5

838-5

938-8

938-3

1,188*0

1,188-0

1,607-9

1,607*9

1,957*8

1,957-8

1,476-4

1,368-1

1,868-1

1,243-5

1,121-0

984-3

843-2

843*2

Low land Railway, 15*460
English miles.

Mountain Railway, 9*714
English miles.

Low land Railway, 16*715
English miles.

Radios of Corves, 820 English feet

52 * CBNTBAL-L ADDER-BAIL1 M0UNTA1B BAILWAY.

//. Construction.

The low land sections will be carried oat according to the existing pro-
ject. The mountain railroad from Klosterle to St. Jacob will be laid
down according to the Rigi system, with this modification, that the whole
length of the permanent way will be protected from the influences of the
climate by masonry galleries or iron coverings where necessary. The
galleries will be provided with ventilators in the roof, and with windows
on their right sides to give light.

III. Time of Construction,

The length of time required to construct the line is calculated at 8 years.
In fixing so long a period we have chiefly to consider the construction of
the covered galleries on the Arlberg, for the mere laying down of the
railroad will be finished long before that.

IV. Cost of setting up the line.

In calculating the cost we will take the chief details from the official
report, excepting the additional items such as covered galleries, per-
manent way, rolling stock, &c.

(a). Low land lines. — Length 82*175 miles. The modification pro-
posed by us in the existing project consists merely in the reduction of the
maximum gradients of 1 in 84£ to 1 in 40, by following the lowest line
of the valley. We can, therefore, take the mileage expenses of this part
from the existing project.

Hence we obtain the following : —

Actual cost of constructing 32*175 miles of low land rail- £

way, at £87,765 per mile, 12,14,748

Loss on capital arising from exchange, at 25 per cent, . • 8,03,687
Interest on the capital sank for 8 years, • • . • 1,13,888

Loss on interest arising from exchange, at 25 per cent, 28,471

Cost of laying down the low land railway, . . 16,60,789
(J). Mountain railway.— Length 9*7189 miles. Double line.

Cost per Mile.

1. Office buildings, as in the existing project, .. .. 198

2. Superintendence, do., .. .. .. .. 644

Carried over, •• 836

1 CBSTBAL-LADDBB-BAIL ' MOUNTAIN RAILWAY. S3

£
Brought forward, • • 836

& Purchase of land as in the existing project, . • • • 1,213

4. Embankments from analogous examples, .. •• 10,575

6. Supplementary works : this head comprises retaining

walls, consolidation of the bank slopes, &c, • . 6,437

5a. Galleries. The whole line will be protected partly
by galleries cut out of the solid rock, partly by gal-
leries of masonry, and partly by roofs of iron. It
is well to note here that although we should only
allow for the masonry or iron galleries, as those
cut ont of the rock have been already inclnded
under the head of embankments, we have adopted
for the whole length of the mountain railway a
price per running yard equal to that of a ma-
sonry revetment of an ordinary tunnel, viz.,
£22 17#. 2J<f. per yard run, 40,238

6. Small masonry works, as in the existing project, • • 8,060

7. Large masonry works, as in the existing project, . • 8,761

8. Ballast, as in the existing project, . • • • 977

9. Permanent way (double line) improved system of

theBigi, 17,701-5

10. Buildings, as in the existing project, • • . • 2,495

11. Fences and signals, as in the existing project, • • 793

12. Boiling stock. 10 powerful locomotives with tooth-

ed wheels on the improved system of the Rigi, also
40 wagons for covered merchandize, • • • • 4,163

18. Sundries, as in the existing project, 242

Cost per mile, •• 92,486)

Cost of Construction.

Actual cost of constructing 9*714 miles, at £92,486} per

mile, V. 8,98,414

Loss on capital on account of exchange, at 25 per cent, 2,24,608}

Interest on the capital sunk during 8 years, at 7} per

cent, 84,226

Exchange on the interest, • 21,056}

Cost of establishing the mountain railway, . . 12,28,300

Recapitulation.

Cost of establishing the low land railway, ,. ., 16,60,789

Cost of establishing the mountain railway , .. .. 12,28,800

Total cost of establishing the line, . . 28,89,089

54 * CKSTRAL-LADDEB-ftAIL ' M0TOTAIN BAILWAY.

t V. Working Expenses.

We have based our working expenses, as in the existing project, on an
1 annual traffic of 4,42,893 tons over the whole length of the line.

(a). Sections of Approach, (Bludenz-Klosterle and St. Jacob-Lan-

deck). — Owing to the maximum gradients of 1 in 34£ adopted in the

* existing project the trains must not exceed 148 tons in gross weight,

which gives a net load of 81 J tons. 5,460 trains will therefore be re-
ft quired to transport these 4,42,893 tons. By reducing the maximum

gradient to 1 in 40 we can, as on the Brenner and Semmering, form trains
of 197 tons gross weight, or 118£ tons net weight, drawn by two locomo-
tives ; that is to say, the expenses of traction being in both cases the same,
I 148 tons of gross load will be drawn over the gradients of 1 in 84£>

while 197 tons will be conveyed on those of 1 in 40. The annual number

t . of trains will thus be reduced to 3,750 on a length of 82*175 miles,

giving a total of 120656*25 train miles. Notwithstanding the easier
gradients which we have adopted, causing as they will a reduction in the
working expenses, we have (to be on the safe side) computed these ex-
penses at the same rate as in the existing project. They will thus be : —

Expenses of traction and maintaining the rolling stock «. d.

per train mile, 8 7§

Cost of maintenance and superintendence of the line per

train mile, 1 9J

Cost of general administration per train mile, •« • • 1 1 J

Whole coet of working per train mile, .. 6 6J

The cost of working 120656*25 train miles of the low land line will
thus be annually £39,339.

(fl). The Mountain Railway. (Elosterle-St Jacob). — The traction
over the Mountain Railway of 197 tons gross weight per train will neces-
sitate very powerful and heavy locomotives, and a consequent increase in
the weight of the permanent way. Each train of the low land line must
therefore be split up on the mountain into two trains, each of 98£ tons
gross, or of 59-^ tons net weight. These mountain trains will be so
made up as during the ascent to be poshed by the locomotive and during

\ the descent to be held back by it. It may be noted that each of the trains

on the low land line being drawn by two locomotives their division into two
parts will not necessitate an increased number of locomotives. The trains

i will leave the terminal stations at intervals of 8 or 10 minutes, so as to

* :

,♦

'ckkybal-laddbr-rail' mouhtain railway. 55

follow each other at a distance of about 1,000 yards, in the same way as on
the Rigi line, where often five trains follow each other at five minutes inter-
vals. It will thus appear that the working of the mountain railway will
be altogether different from that on the low land line, and that the two
stations Klosterle and St. Jacob will have to be considered as stations for
breaking up the trains. The paying load of each train being 59-jV tons
7,500 trains will have to be ran to transport 4,42,893 tons. If 360 work-
ing days be taken in the year 20 or 21 trains mast be ran daily. These
7,500 trains will travel over 9*714 miles, thus giving 72,855 train miles.
From these data we will estimate the rolling stock required thus:—
Assuming an average speed of five miles per hour each locomotive wijl run
backwards and forwards between Klosterle and St. Jacob twice in a work-
ing day of 8 hours. Five or six powerful locomotives will then suffice' for
20 or 21 trains to and fro per diem. To meet all contingencies we will
pot down the number at ten. As this railway will chiefly carry the wagons
of other lines we shall not require so large a number as we otherwise
should do, and 40 wagons ought to be sufficient. This method of work-
ing being agreed to we obtain the following estimate.

/. Cost of Traction and of Maintenance of the Rolling Stock.

& 9. <L
Fuel — On each train mile with a gross load of 98} tons,

the consumption of f nel will be : —

2376 cwt in ascending.

'397 „ in descending.

2J2-772

or 1*886 „ as an average, which at 1*. 1\d. gives,. • 0 2 2]
Oii for Locomotives— -0118 cwts., at £1 17*. 9J&, . . ..005
Oreaae for the toothed driving wheel and rack rail—
•0076025 cwts., at 16*. 9A, ,.002

Engine Drivers? Wages, #•(?.

£ s. d.
1 Conductor, . . .. .* .. ..080

1 Stoker, 0 4 9\

1 Cleaner, .. .. .. •• ..025

1 Engine workman, .. •• .. •• 0 4 0

Materials, .. •• 0 17

Sundries, .. 0 8

Total, .. £1 4 0

Carried forward, ..0 2 9|

•—■«■■__«

56 « CBNTRAL-LADDBE-BAIL ' MOUHTAIN RAILWAY.

£#. a.

' Brought forward, ..0 2 9f
As each locomotive makes daily four trips of 9*714 miles each,
there will be 38*856 train miles. Therefore each train mile
will cost, 0 0 H

Total, ..035

II. Maintenance and Superintendence of Permanent Way.

These will be required for the whole line yearly.

1 Overseer yearly, 100

2 Chief Fitters, at £80 per annum each, 160

15 Railway Watchmen, at £40 each yearly, . • • • 600

7,200 days wages of ^laborers, or 360 days with 20 men on

each day at 3#. each, 1,080

We must besides estimate for the maintenance of the fol-
lowing items, the cost of constructing which per mile will

be—

£
Galleries, 40,233

Masonry Works, 6,821

Ballast, 977

Superstructure, •• .. 1770*5

Fences and Signals, • • . • . 793

Buildings, 2,495

Cost per mile, .. 69,020|
Taking a co-efficient for maintenance of abont 7 per cent, on the
cost of construction, we obtain 4,700

Total, .. £6,640

These working expenses are distributed over 72,855 train miles. «. d.
Hence the cost per train mile will be •• 1 9$

III. Cost of General Administration.
Taking this as in the existing project, which has a long tunnel, s. d.
the cost per train mile will be 1 1ft

Recapitulation. — The working expenses of the mountain railway

per train mile will thus be—

$. d.

1. Traction and maintenance of rolling stock, .35

2. Maintenance and snperintendance of permanent way, •• 1 9|

3. General administration, 1 H

Total, ..6 4

' CENTRAL-LADDBR-RAIL ' MOUNTAIN RAILWAY.

Thus for 72,855 train miles of mountain railway, a total is ob-
tained of 28,070

The whole working expenses on all the line will thus amount to

annually —

1. On the low land line, 89,339

J. On the mountain railway, 23,070

Total, .. 62,409

which sum capitalized at 5 per cent, represents a capital of £12,48,180.

VI. Comparative Table of leading features.

Railway with long
tunnel, {the
emieting project.)

Mountain railway

with raok rail.
(proposed project).

Length of line without tunnels, or over

the

low land, • • • • • •

• •

31*707 miles.

32*175 miles.

Length of line in tunnelling, or length

mountain railway, • • • •

• •

7*86 miles.

9714 miles.

89*567 miles.

41-889 miles.

Height above the sea of highest point,

••

4,186 feet

5-673 feet

if^iimiwi gradient of low land lines,

• •

1 in 844.

lin40.

if»im»tti gradient of mountain railway,

a •

■ •

1 in 12).

Difference of level in the ascent,

• •

2,828 feet

2,810 feet

Do. da descent,

• •

1,571 feet

1,444 feet.

•

Whole difference of the heights, • •

8,894 feet

3,754 feet

f 1 in 47, low land

Average gradient over whole length,

• •

lin63.

J line.

J 1 in 13), moun*
I tain railway.

Badius of sharpest curves,

• •

820 feet

Time required for construction, • •

• ■

8) years.

3 years.

VOL, V. BBCOVD 8KBIB8.

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'CI1ITRAI.-I, ADDER-RAIL' MOUNTAIN RAILWAY. 61

The entire cost of Construction and Working.

Tunnel Railway. Mountain Railway.

Cost of construction, £44,56,817 £28,89,111

Cost of working capitalized, .. „ 14,08,740 „ 12,48,180

Total, .. £68,65,557 £41,87,291
Whole saving, .. £ 17,28,266

VII. — Conclusion.

(a). In the cost of establishing the railway, a saving of £15,67,706
is thus shown in favor of the rack rail system. This saving
arises in a great measure from the suppression of the tunnel,
and ought to be considered if anything below the mark, because
in our opinion even the approximate cost of piercing a long
tunnel is beyond all ordinary calculation, and may very
likely prove too small. In the cost of working capitalized
a saving of £1,60,560 is shown in favor of the rack rail
system. The financial results both in construction and work-
ing are thus entirely in favor of our project.
(&). The first objection which may be raised to our project is, that
we cross the top of the mountains at an altitude of 5,873 feet
—or 1,686 feet higher than is done in the existing project,
and that this will consequently expose our railway during
winter to very unfavorable climatic inBuences. To this we
would reply, that our estimate allows for the mountain rail-
way being protected throughout its length against the in-
clemences of the winter by galleries admitting light, and
affording an escape for the smoke of the engine. If this
arrangement proves successful it cannot be doubted that the
railway will be able to run at an altitude of 5,873 feet
without interruption to its service. It is equally also beyond
doubt, that if the Rigi Railway was protected by galleries
the trains could run regularly during the severest winters
to Kulm, that is to the same height of 5,873 feet above the

sea.

»•

62 < CENTRAL-LADDER-RAIL ' MOUNTAIN RAILWAY.

(c). It might also be objected that the wear of the rack-rail system
will be considerable. Bat we reply that the experience on
the Rigi daring foar years has shown that this wear is quite
insignificant, and even less than that of ordinary railways ; in
fact, there is an economy under this head which we have not
allowed for in our calculations.
(d). As for the safety of the ascent and descent, it has been proved
on the Rigi, that it is at least as great as on ordinary rail-
ways ; one reason being the slow speed of the trains, and the
other the adoption of powerful breaks, which can effect the
immediate stoppage of the train. On the Rigi there has
never been the smallest accident in spite of its very heavy
traffic and its gradients of 1 in 4.
(«). With regard finally to the working of the railway, it might per-
haps be considered irrational that all trains running the
whole length of the line must be raised up to a height of
5,873 feet, leading thereby to an increase in the work done,
and so far burdening the cost of working. But we would
observe, that if this height were crossed by means of a rail-
way trusting only to adhesion on a gradient of 1 in 40 or 1
in 33$ the annual cost of working it would be much increased,
and would far exceed the interest on the capital outlay on
the tunnel, as owing to the liability of the locomotives to
slip a much greater expenditure of steam would be re-
quired. With the rack rail system on the contrary there is
no slipping, and the whole of the steam generated by the
locomotive is utilized in producing motion. The results of
the preceding calculations in other respects fully confirm
what we have said.

The annual saving in working consequent on the £

adoption of the Mountain Railway will be, . • 8,020

Interest at 5 per cent, on the sum saved by the rack

rail construction, 97,983

Total annual saving, • . £ 1,06,003

which will consequently permit of a reduction of 36£ per
cent, in the tariff, or in the cost of transport allowed for in
the existing project.

* CENTRAL- LADDER- RAIL* MOUNTAIN RAILWAY. 68

In conclusion, we believe we can state with perfect truth, that the
adoption of oar project for a railway over the Arlberg will afford the
important advantage of reducing the capital outlay by about £1,740,000
without any drawback to the working of the railway in respect to its
international character.

Aarau,
27th November

,1874.)

Note by TranBlator. — It has by many been supposed that the Rigi system could
only meet a large passenger traffic, but it is now proposed for an annual traffic of
nearly 4,50,000 tons, or a daily traffic of from 1,500 to 2.000 tons. To carry this
traffic it is to be laid on a gradient of 1 in 12$, this being the same gradient on which
Fell's system has been laid in, Brazil. But whereas Fell's engine has only been able
to drag 27 tons, the Rigi engine is calculated to push up 60 tons of paying load on
this gradient On the Arlberg (a double line) the entire working expenses are
calculated at 6s. 6d. per train mile, but the cost of the traffic service (such as wages
of ticket collectors, porters, &c,) seems to be omitted. The following figures are

obtained from the above report : —

Number.

Number of engines per mile worked, '97

Train mileage per engine per annum, • • 7,285*5

Banning expenses, repairs and renewals per engine per annum, . . £ 1,244

Hie accompanying comparative Tables will probably be of service.

'CENTIUI.-I.ADDKH-HAIL MOUNTAIN RAILWAY.

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16-66

si -n

FORMATION OF A HARBOUR AT MADRAS. 65

No. CLXXXVIL

FORMATION OP A HARBOUR AT MADRAS.

[Vide Plates XVI. and XVIL]

Report by W. Parkbs, Esq., M.I.C.E., to Govt., Fort St. George.

Dated Madras, 4th November, 1873.

Sir, — In accordance with instructions given to me by the Secretary of
State for India, at the request of the Government of Madras, I arrived
at this place on the 29th September, and was engaged for the five follow-
ing weeks in prosecuting such personal inquiries, observations and in-
vestigations as I considered necessary to enable me to submit to you my
conclusions as to the best mode of providing shelter for shipping*

2. Sources of information. — I have received every possible assistance
from the officers of all the Government Departments to whom I applied,
from those of the Madras and Carnatic Railway Companies, and also from
several of the leading Merchants of the place, and from the Secretary of
the Chamber of Commerce. I have also had opportunities of conferring,
-with the Commanders of several of the ships lying in the roads at the
time of my visit, and have received from them valuable information on
nautical points.

8. Previous study of the question. — It is right that I should state at the
outset, that my attention had been given to the subject for some time pre-
vious to my receiving official instrnctions to report, and while in England,
I bad the advantage of repeated conferences with Captain A. D. Taylor,
I.N., an Officer of great experience and eminence as a Marine Surveyor
of this coast, and also with Mr. J. J. Franklin, R.N., for many years

VOL. V.— SECOND SERIES. K

66 FORMATION OF A HARBOUR AT MADRAS.

Secretary of the Marine Board of Madras, as well as with other gentle-
men of local experience then in England.

4. Invitation to visit Madras. — As a result of the information thus
obtained, I felt myself justified in submitting to His Excellency the Go-
vernor of Madras, in August 1872, some remarks, in which I called in
question the correctness of certain conclusions which had then recently
been laid before the Government and were under its consideration. It
was, I believe, in consequence of this that I was invited to undertake a
personal investigation of the whole question on the spot In doing this,
however, I have subjected all my previous conclusions to the most rigid
tests, and though those which I have now to submit are substantially the
same, yet I am enabled to base them on information locally obtained, and
I can put forward my recommendations in a more complete form, and my
estimates of cost and of results to be obtained with greater confidence.

5. Blackwood '* Harbour and inland docks. — I have not thought it ne-
cessary to devote much time to considering the details of two proposals
which, in former times, have met with some support, because it appeared
to me that neither was calculated to effect the object in view. These are,
first, the removal of the trade of Madras to some locality, such as Black-
wood's Harbour, more favoured by nature ; and, second, the formation of
inland docks and basins.

6. Breakwater and close Harbour.— The two proposals between which
the choice now lies, are, first, a breakwater entirely detached from the
shore, and parallel to it ; and, second, a harbour formed by piers running
out from the shore into deep water, and termed a "close harbour."

7. The former of these systems is advocated from two totally different
and independent points of view, and, so far as I am aware, no one (unless
the Master Attendant, whose recorded opinion I shall presently quote at
length, be an exception) advocates it on both grounds.

8. Breakwater Committee.— The Committee appointed by Government
in 1868, known as the Breakwater Committee, reported in January 1869,
as follows, paragraph 40 : — " If it were possible to construct an enclosed
harbour, which should be secure from the danger of shoaling up, we
should not hesitate to recommend it in preference to a breakwater. It
would be greatly superior to the latter iu every respect. The piers would
be constructed from the shore, and at far less expense in proportion to the
material used than the breakwater, the accommodation for shipping and

Km OF THE TOWN, AND MM0STHD OF MAORIS,

I 3ktui» f the Harbour prof Bled in Mr. Parke*' Depart).

FORMATION OF A HABBODB AT MADRAS. 67

the facilities for lauding and shipping cargo would be greatly superior to
those afforded in an open harbour. Bat we consider that all these advan-
tages would be rendered nugatory by the shoaling of the harbour, which
would certainly result from the construction of any solid piers or groynes
from the shore ; and we are strongly of opinion that a breakwater is the
one work from which any real improvement is to be hoped.'1 Such is the
riew held by one class of advocates for the breakwater system.

9. Mr. Robertson. — Mr. Robertson, Harbour Engineer for India, says,
(Reports, first series, p. 62) :— " I have come to the same conclusion as
the Committee, but from entirely different reasons. I have shown that
there may be as much, if not more, danger from shoaling in the case of a
breakwater as of an enclosed harbour ; but taking all the circumstances
connected with Madras into consideration, a breakwater appears to me to
be preferable to an enclosed harbour. For an equal sum of money it will
give much more deep water shelter than a harbour ; it will create a con*
siderable length of sufficiently smooth water at the coast line to enable
boats to land or to come to jetties, and vessels can enter and quit more
easily from behind a breakwater, than through the one entrance of a har-
bour."

Thus, in Mr. Robertson's view, the shoaling objection would, if valid, be
equally fatal to either system ; but his opinion as to its validity, though
not expressed, is, I cannot but think, very clearly implied to be in the
negative.

10. Sir Arthur Cotton.— Sir Arthur Cotton in the able and suggestive
paper he gave me before 1 left England, and which the Government at
my request has printed and distributed, is less reticent. He argues from
facts within his own experience, that the along shore movement of sand is
not sufficient to interfere with the success of an enclosed harbour, but he
prefers the breakwater on grounds very similar to those expressed by Mr.
Robertson, being mainly of a nautical character. Similar views are I
believe held by others whose opinions are entitled to every consideration.

11. Fear of shoaling, groundless*— I agree with Sir Arthur Cotton
that the fear of shoaling either in the case of a breakwater or of an en-
closed harbour is groundless, and I agree with the Breakwater Com-
mittee in their opinion as to the superior advantages of an enclosed harbour.

Advantages of breakwater exaggerated. — I further think that both
classes of advocates of the breakwater have much over-estimated the ad-

68 FORMATION OF A BARBOUR AT MADRAS.

* vantages to be derived from it. I have now to gi?e my reasons for these
conclusions.

12. Grounds of fear as to shoaling not definitely given. — First, as to
the fear of shoaling. The Breakwater Committee and the professional
witness by whose opinion they appear to have been mainly influenced
Colonel (now Major-General) C. A. Orr, R.E., have expressed their
conclusions npon this point in the most emphatic and confident terms.
Bnt in searching for the grounds of these conclusions, one cannot bnt be
struck with the comparatively hesitating and indefinite terms in which
those grounds are expressed. The Committee, in their remarks on Mr.
Fraserts project for a close harbonr, say : " We consider there is strong
reason to conclude that if a beach is extended a hundred yards by means
of groynes, it might be extended a hundred yards further by continuing
the process, and in each case a new line of beach being formed precisely
similar to the original beach, there would appear to be nothing to pre-
vent the shore being extended to any amount that might be desired.1'

13. Colonel Orr. — Colonel Orr passes over the matter very lightly in
his evidence ; but in a memorandum by him appended to the report, he
says : " It is evident to all who have had opportunities of studying the
circumstances of the Madras beach, that any obstruction opposed to the
currents must necessarily have the effect of arresting the passage of
the sand which is in constant movement by the combined action of the
surf and those currents, and of causing it to accumulate to windward of
the obstacle. The accumulation would at first form merely an extension
of the beach seaward in the angles between the training walls and the
shore ; but it would ultimately, I have no doubt, carry the line of the
coast to the outer end of those walls, and close the entrance between
them."

14. Period required for advance of Coast line not estimated. — The
natural process is, I believe, correctly described by Colonel Orr, but evi-
dently the practical conclusion depends upon the meaning we are to attach
to the indefinite term " ultimately." Does this refer to a future time to
be reckoned by years, by generations, or by centuries ? I presume that
neither the Committee nor Colonel Orr, can have meant to assert that
the second hundred yards would accumulate as fast as the first, the third
as the second, and so on. They cannot have failed to take into consider-
ation that every hundred yards of advance of the beach involves a greater

FORMATION OF A HARBOUR AT MADRAS.

depth of water to be filled, and a greater length of coast to be covered
by the triangular accumulation, and consequently a slower rate of advance
for erery successive hundred yards. But evidently they can have made
do attempt to form even an approximate estimate of the decreasing rate
of adrance.

15. Rate of advance decreasing. — I might quote many instances of
groynes, piers and other obstrnctions carried out from sandy beaches sim-
ilar to that at Madrag, in which the rate of advance has been rapid at
first, bat in a few y3ars so slow as to place the ultimate extension of the
sand to the head of the obstacle in so distant a future as to render it
practically no element in the question. It might be urged with respect
to any one instance that the circumstances are different to that of Madras,
bat the cases are now so numerous as to throw the anus probandi on those
who assert that Madras is an exceptional case. In some of the cases
there were predictions of the same nature, and as positive as those given
in regard to Madras, but in every instance they have been signally falsi-
fied. There are plenty of instances of small groynes being buried and
mail harboar entrances being choked by sand, driven along the beach as
Colonel Orr describes ; bat in every case in which piers on a large scale
hare been carried out, the advance of sand has been left far behind. I
ipent mnch time before I left England in investigating the history of all
the cases of which I could find any record, and satisfied myself that the
general rule is as above stated, and that Madras might legitimately be
concluded to be subject to the same rule, unkas reason could be shown
for its being an exception.

16. Sir Arthur Cotton's experience.— Upon this point the evidence of
8ir Arthur Cotton is of the highest value. He had constructed groynes
on the beach at Vizagapatam, and had carefully watched and recorded
their effects. Those effects were of the same character as I have described
above, and Sir Arthur had subsequently an opportunity, while Chief En-
gineer at Madras, of comparing the circumstances of that beach with
those of Vizagapatam. He saw no ground for supposing them to be
materially different, and unhesitatingly applied his Vizagapatam expe-
rience to the case of Madras.

17. Records of effect of Groynes. — Since my arrival at Madras, I have
gone a step further. I have searched the whole of the records in the
office of the Chief Engineer in connection with the accumulation of sand

70 FORMATION OF A HARBOUR AT MADRAS.

by the groynes constructed some years ago. I found it reported that
when the groynes. were short, the spaces between were quickly filled with
sand, but when they were longer, one season was not sufficient for the
accumulation. On one occasion in 1857, an estimate was made by Cap-
tain Rawlins, the Engineer in charge of the groynes, of the quantity of
sand accumulated in a season by the groynes in front of the fort, and by
that opposite the light-house, and those opposite Messrs. Arbuthnot's
and the Custom-house. The area was in the aggregate 22£ acres, and
the depth three to four feet, and the spaces were not filled. Taking this,
therefore, as a measure of the quantity of sand which could be arrested in
one year, I found that in order to fill in a triangular area of similar form
between the coast and a pier extending 1,200 yards from shore, a period
of 180 years would be required.

18. Experience of other places. — This result though of course only ap-
proximate, is so completely in accordance with the experience of other
places, as to remove all doubt that the accumulation of sand at Madras
will not be so rapid as to cause any practical inconvenience to a harbour
formed by piers running out from the shore. I may mention three cases
in which definite results have been obtained : — At the harbour of Great
Yarmouth, on the east coast of England, exposed to a drift of sand from
the northward, that drift was arrested for forty years by a pier less than
200 feet long ; at the port of Bayonne in France, situated at the southern
extremity of a line of several hundred miles of sandy coast, exposed to
the heavy north-westerly seas of the Bay of Biscay, works constructed
just within the shore line 800 years ago, are now 1,200 yards inland; at
Port Said, exposed to a constant drift from the westward, the experience
of ten years furnishes data, according to the Admiralty Chart of 1870,
for the conclusion that 150 years will elapse before the wave-driven sand
can pass the pier head, which is now 2,200 yards seaward of the present
coast line.

19. Supposed advantages of Breakwater. — I stated in paragraph 11
that 1 considered the advocates of the breakwater had over-estimated the
advantages to be derived from it This conclusion is not based on the
examination of any definite estimate of such advantages, for none such
has been put on record, but rather from the statements of existing evils
which it is assumed the breakwater would remedy. The nearest approach
to an estimate is that given by Mr. Robertson, and quoted in paragraph

FORMATION OF A HARBOUR AT MADRA8. 71

9, viz., that it would give more deep water shelter than an enclosed har-
bour of the same cost, and that it would create a considerable length of
sufficiently smooth water at the coast line. Sir Arthur Cotton considers
that " the breakwater would leave the space behind it exposed to a ripple
from northerly or southerly winds, but not to any swell."

20. Want of data for estimating effect of Breakwater.— These are cer-
tainly yery vague estimates on which to base a recommendation for so
large an expenditure, but that they are not more precise is due to the fact
that there exists no experience, and even no theory on which such an es-
timate cuuld be based. Mr. Thomas Stevenson, in his valuable treatise
on Harbours, states that he has " been unable to find that a single
observation or experiment of any kind has been made upon the subject."

That there will be some shelter behind a breakwater lying parallel or
nearly so to the ridges of the advancing waves, we cannot doubt ; but
there are absolutely no means of judging better than the merest guesses
to what extent the deflected waves will roll in through the wide spaces at
either end, and what length of breakwater would be necessary to prevent
them from meeting in the space between it and the shore, and creating
cross and confused seas more troublesome to ships, and more dangerous
to boats then the regular swell of the ocean. Where the length of break-
water is sufficient to allow the waves entering from either end to spend
themselves, and leave a space between, in that space there will be com-
plete shelter. Whether the length of 2,000 yards is, or is not sufficient
for this purpose, I cannot say positively. If I were to hazard a guess, it
would be that it is insufficient.

21. Direction of Seas. — So far I have assumed that the seas will
advance upon the breakwater from that direction which gives it the
greatest advantage, that is at right angles or " broadside on," or in the
case of Madras from the eastward. But it is evident that to a sea set-
ting from the northward or the southward, the breakwater would be " end
on " and of no use whatever. Probably no great force of sea ever comes
from these quarters, but I am informed that during the north-east mon •
soon, the waves, though breaking nearly parallel to the shore, have, at the
distance at which it is proposed to place the breakwater, a direction much
nearer to that of the wind which raised them, and would therefore strike
the breakwater very obliquely. This would reduce the width of the shel-
tered area, and the sheltered part of the beach would be somewhere near

72 FORMATION OF A HARBOUR AT MADRAS.

the light-house instead of opposite the business part of the town A
work which would offer so little protection daring the annual fool weather
season wonld not do much for the port.

22. Comparative shelter of Breakwater and closed Harbour. — From
what I have said of the uncertain character of the shelter to be obtained from
a breakwater such as proposed, it will be easily understood that I cannot
bring to any definite test Mr. Robertson's opinion, that it wonld proyide
more deep water shelter than a closed harbour of the same cost. I will,
however, for the moment assume that the shelter would be as complete
as its advocates appear to think. On such an assumption, the number of
ships that could be moored on the same system would be about equal in
the two cases. On the most favourable assumption, the breakwater will
not therefore give the superior accommodation claimed for it.

23. Effect of Hurricanes. — Sir Arthur Cotton says that this question
of shelter for shipping is not to be settled by what happens in a hurricane.
In this I quite agree. I doubt whether any plan would give absolute
immunity from danger during such exceptional times, still it is desirable
to ascertain precisely what are the dangers to which shipping are exposed
at such times, and what will be the effect of works intended for their
protection in more ordinary times.

24. Description of Hurricanes. — I think, with this view, it may not be
without use for me to present, in a more definite form than is ordinarily
accessible, the leading features of the hurricanes which occasionally visit
Madras. It does not fall to the lot of many persons to be eye-witnesses
of more than one or two of these severe storms, and this partial experi-
ence is apt to lead, either on the one hand, to a too hasty generalization,
or on the other, to an equally hasty conclusion that the phenomena mani-
fested are incapable of being definitely classified.

25. Observatory records. — To enable me to do this, I have been favoured
by Mr. Pogson with not only a sight of the complete meteorological records
of the Government Observatory, but also with his personal assistance
in extracting from them the leading features of the several storms which
have occurred since 1787, a period of over three-quarters of a century.

26. Three classes of Hurricanes. — I give in an Appendix the ex-
tracts which we made, and I now submit the general conclusion to be
drawn from that statement. A very little study of it will show that the
storms may be divided into three distinct classes, and the generally

FORMATION OF A HABBOUB AT MADRAS. 78

cepted theory of revolving storms or cyclones, identifies these classes as
those in which the centre of the storm passes respectively over Madras,
or wrath, or north of it.

27. First class — central. — Storms of the first class occurred in October
1797, May 1811, October 1818, and October 1886. In all these cases
the wind commenced at or near north, blew for some hours with great
force, then there was a lull of half an hour or less, and then it blew again
with equal violence from the south. In no case, except perhaps in 1811,
ss to the particulars of which there appears to be some doubt, did the
wind come at any time from the eastward.

28. Second class— centre south of Madras.— Storms of the second
class, centre south of Madras, occurred in December 1807* November
1846, November 1848, May 1850, November 1864, November 1865,
and May 1872. In each of these seven cases, the same course was fol-
lowed, the wind rose at about north, then gradually increasing in force it
veered towards east, maintaining its force. After passing east it gradually
fell, and by the time it arrived at south, was either very light or merged
in the ordinary periodical wind.

29. Third class— centre north of Madras. — Storms of the third class,
centre north of Madras occurred in November 1787, May 1788, March
1820, May 1827, May 1841, May 1848, October 1846, May 1851, and
November 1856. In these ten cases, the courses of the wind were much
leas regular than in the two preceding classes. It kept rapidly shifting
about with apparent irregularity through the western half of the compass,
nerer during the height of the storm being in the eastern half, except on
one remarkable occasion (October 1846), and perhaps one or two other of
the earlier ones, when it made a rapid circuit of the whole compass round
by west, north, east and south.

30. Summary, — It thus appears that in only one out of the three
classes (with the one exception just noted) did the wind blow from the
east, in only one from the south with any force, but in all from the north.
I may add that strong winds never blow from the eastward at Madras,
except at the tails of the one class of cyclones.

31. Preponderance of northerly winds — direction of waves. — This
statement shows that in extraordinary as well as in ordinary weather
Aere is a great preponderance of strong northerly wind*. During ordinary
times it is the north north-east wind of November, and December alone,

VOL. V.— SECOND BBBIES. L

74 FORMATION OF A HARBOUR AT MADRAS.

or rather the sea raised bj it, which interferes in any serious degree with
the trade of the port as carried on the present rude system. It is of
coarse from the waves rather than from the wind that shelter is required,
and these no donbt in the gradually shoaling water advance from a more
easterly quarter, but the assumption that they come from a direction
nearly at right angles with the proposed breakwater is not borne out by
the information I hare received. If the question between a breakwater
and an enclosed harbour depended upon this, it ought to be made the sub-
ject of more systematic observation before assigning any precise weight
to the argument, but I have no hesitation in saying that a roadstead
exposed to the most prevalent and strongest winds, even irrespective of
the direction of the heaviest seas, cannot be considered to be effects
ally sheltered.

32. Having now shown that the only objection to an enclosed harbour
which has been put forward as fatal, is groundless, and that the advan-
tages to be derived from a breakwater are very uncertain as to their extent,
and on the most favourable assumption very incomplete, it only remains
for me to describe the work which I consider most suitable to the locality
and the circumstances.

83. Principles en which design is based.— In determining upon the
scale of my design, I have endeavoured to keep in view the following
principles : first, that it should be sufficient for, but not in excess of, the
present requirements of the trade ; second, that it should be capable of
extension if it should become necessary to provide for an increase of trade,
or greater accommodation for shipping ; and third, that the outlay upon it
should not render necessary increased expenses in the trade of the port, so
as to enhance the cost of goods exported or imported, or throw any per-
manent burden on general or local revenues.

84. Whether this last condition is absolutely necessary, it is not for me to
say, but if it can be fulfilled it is undoubtedly a desirable one, as it would
render the undertaking at least self-supporting if not pecuniarily profitable.

85. Source of Revenue. — The source to which I look for revenue to
pay interest on the necessary outlay is the appropriation of the saving
which may undoubtedly be effected upon the expenses to which the trade
is exposed by the present rude system of landing and shipping cargoes.
This is not only very costly in itself, but it subjects the cargoes to much
damage in their passage between the ship and the shore ; and by the alow-

FOBMATION OF A HARBOUR AT MADRAS.

seas, awkwardness, and uncertainty of the operation, causes great deten-
tion of the ships. The removal of all these evils may be represented by a
money value which may in some form or other be carried to the credit of
a harbour revenue.

88. Present system very expensive.— In what particular form the charge
should be levied is for the persent an immaterial question. I am now
only concerned to show that such a saving is possible, and that it would
be on a scale commensurate with the required interest on the capital to be
sunk. In proof of this I would refer to the accompanying table which
shows the comparative cost by official tariff of landing and shipping cargo
at Madras, as an open roadstead and at Kurrachee, a smooth-water har-
bour. The charges for lightering to and from the roads outside the har-
bour at Kurrachee (now however never incurred) are given to show their
general coincidence with the Madras charges under similar conditions.

Comparison of the Cost of Landing and Shipping Cargo at Madras and

at Kurrachee from Official Tariffs.

Madras. ] Kurrachzs.

Hair Weather* Harbour. 1 Road*.

Imports.

Exports.
Cotton and wool per 100 bales, .. . .

B8, A. P.

84 6 0
11 0 0
45 12 0
22 14 8
1 14 0
16 0

27 8 0

11 0 0
45 12 0
11 0 0
84 6 0

BS. A. P.

25 0 0

4 0 0

15 0 0

10 8 0

0 12 0

fO 12 0

12 0 0
8 0 0

20 0 0

BS. A. P.

85 0 0

10 0 0
25 0 0
20 0 0

■ •

20 0 0

10 0 0
20 0 0
18 0 0
40 0 0

37. Cost at Madras with a Harbour. — I believe the actual charges at
Madras with a smooth water harbour would be less than at Kurrachee,
as at the latter place the distance for lighterage is from two to three miles,
whereas at Madras it would be about half a mile, and also the supply of

skilled boatmen is more limited. I have based the Madras charges on

RS. A. P.

... ••« »M i o O

.■• .•• ... w O v

... ... **• v 1 U

isoeX) ... •••

Police Peon, ... ...

Tarpaulin 4 as. ( occasional),

t Exclusive of cooty hire lor discharging from lighter*.

2 12 0 for 2 tone.

76 FORMATION OF A HARBOUR AT MADRAS.

the tariff for Masula boats to the beach. The charge to the pier is less
by the amount of pier due, which equalizes the cost to the trader. If the
pier were enclosed in a harbour, ships would come alongside of it, and
discharge direct, and so would save lightering altogether, thus giving to
the pier an advantage equal to that given to the beach-landing system.
I am informed that some merchants have contracts with the Masula boat-
man at less than tariff rates, but, on the other hand, there are frequent
extra rates, so that the tariff may be taken as a fair average.

38. Estimated amount of saving. — I believe that in assuming the saving
in landing and shipping operations, and other consequent expenses, at a rupee
per ton of goods, I am under the mark, but assuming this figure, and apply-
ing it to the lowest estimate given of the number of tons landed and ship-
ped last year, viz., 2,75,000, we may rely upon a revenue derived from sav-
ings only of £27,500. This would pay interest at 4 per cent, on £6,87,500 ;
at 4£ per cent, on £6,11,000, and at 5 per cent., on £5,50,000.

89. Estimated cost of Works. — A harbour made according to the ac-
companying plan would cost £5,65,000, including 10 per cent, for con-
tingencies, and 5 per cent, for superintendence, and therefore seems to be
within the resources of the trade of the port. It is intended to be formed
by piers running out from the shore 500 yards north and south respec-
tively of the present screw-pile pier, enclosing a rectangular space of
1,000 yards long by 830 yards wide, or 170 acres, with a depth at low-water
of from three to seven fathoms, and consequently available for European
ships of all sizes, with a further space of a quarter of that area with a
depth less than three fathoms, available for boats, lighters, and native craft.

40. Accommodation in Harbour.— Such a harbour would contain 13
ships of various sizes, from 4,000 to 700 tons, secured closely to fixed
moorings, and able to swing, each in its own circle, clear of one another,
also three ships alongside the pier, making 16 in all. If the ships were
more closely moored so as to swing clear of the next ship's mooring, but
not of the entire circle she would describe in swinging, the number would
be increased threefold. This I am myself satisfied might be done with
safety, since ships would be completely cut off from the strains and un-
equal disturbances of swell and current, and acted on only by wind. But
this is rather a matter for the consideration of the Nautical Authorities,
and its determination is not urgent.

41. Accommodation for maximum number not required.— Taking, how-

VOBMATIOB OF A HARBOUR AT MADRAS. 77

«w, 1 6 ships as the limit of the capacity of the harbour, I am informed
that more than this number hare been in the roads at one time on certain
extraordinary occasions. I do not think, however, that it would be wise
to incur the expense of providing for a repetition of such extraordinary
contingencies. In the first place they are not likely to occur again un-
less as a consequence of a great increase of trade, because the effect of the
increased employment of steamers is to facilitate the despatch of vessels
from the port, and leave room for others, and this despatch will be further
facilitated by the improved system of landing and shipping cargoes. In
the second place, such a press would only occur during the most busy
season, which is also the line season, when ships would be as safe as
they are now outside the harbonr, bnt would have the advantage of the
improved system of lightering to facilitate their despatch. I therefore
think that the additional expense which would be incurred by enlarging
the harbour, so as to contain the maximum number of ships on record,
would not produce any commensurate advantage.

42. Possible extension of accommodation. — But though I do not think
it would be wise to incur expense in anticipation of increased trade, a
policy which has often defeated its own object by crippling the immediate
resources of the port, it is yet of the highest importance to be prepared
for future extensions whenever increased trade or other circumstances may
demand it This has been specially kept in view in designing both the
plan of the harbour, and the details of construction.

43. Section of piers. — It will be seen by reference to the section of
the piers appended, that they are proposed to be formed of a submerged

u ' t *

mound of rubble stone from the natural bottom to a depth of 22J feet

78 FORMATION OF A HAHBOUB AT MADRAS.

below low-water. Above this they will consist of two solid walls of con-
crete blocks laid close together so as to form one wall 24 feet wide. This
is very similar to the system followed in the case of a breakwater lately
completed at Knrrachee.

44. Not in the first instance available as quay walls.—* The two faces
of such a pier are of such a character that ships might come alongside
them, bnt it would be useless for them to do so, because the width of the
pier, 24 feet, is insufficient for the purposes of a quay, and that on the
weather side of the harbour would be exposed to the sea washing over it.
To make the piers available as quays in the first instance would involve
an additional cost, for which I do not think there would be an immediate
equivalent.

45. Quays to be ultimately formed. — But I look forward to this as a
second step, which in due time will be very advantageous. The pier as
first constructed would be a mere sheltering breakwater. When the trade
requires more accommodation, I propose to form another similar shelter-
ing breakwater at a distance of, say, 100 yards from the first, and parallel
to it, as shown by the dotted lines on the plan. The original pier would
then be so far removed from the breaking sea, that ships might lie along-
side without inconvenience, and the space between the two parallel piers
being wholly or partially filled up, a wide quay would be formed, on which
goods might be landed, and on which sheds and warehouses might be built,
and thus greatly improved facilities for carrying on the business of the
port would be provided. Such a quay wall would accommodate six or
seven ships alongside of it, in addition to those swinging at moorings.

46. Further extension of works as may be required. — Should the exten-
sion of trade require still further accommodation, a second harbour similar
to the first could be formed north or south, one side being already provid-
ed by the pier and quay of the first harbour. For the present, however,
it is enough to consider the merits or demerits of 6uoh a scheme as the
present trade of the port is adequate to support.

47. Facility for Entrance and Exit of Ships. — I have already said that
the principle of a closed harbour has been objected to on nautical grounds
and the preference given to a detached breakwater, because ships can enter
or quit more readily in any wind. This argument would apply with still
greater force in favour of the proposal to leave the roadstead in its pre-
sent exposed state; for I fear there is no getting over the objection that

FOBMATIOH OF A HABBOUB AT MADBA6. 79

every obstacle to the entrance of wares is, to a certain extent, an obstacle
to the passage of ships. A ship, however, is more easily guided than a
wave, and the objection, whatever it may be worth, becomes simply a
question of the cost of employing steam-power. It is, however, in my
opinion, worth very little.

48. Objections urged by the Master Attendant. — In order to give the
fullest prominence to the objections made, on nautical grounds, to the
principle of a closed harbour, and especially to the special form I have
adopted, I append a report by Mr. Dalrymple, the Master Attendant of
Madras, commenting on my first proposal, bat in terms which are equally
applicable to the present :— .

u I have the honor to acknowledge receipt of the papers specified in the margin,
and to offer a few remarks on the project for the formation of a dose harbour at
Madras.

u 2. I shall first deal with Mr. Parkes's letter, and his able " Note n in a nautical
point of view, without presuming to touch on the engineering phase of the question.

M3. In paragraph 11 of his **Note," he is, I think, in error in assuming that at
Knrrachee there is a heavier sea than at Madras. In cyclones and gales of wind on
this coast, the storm-waves cannot be surpassed.

M 4. With reference to paragraph 21, 1 have only to state that, according to oar
experience and my own personal observation, every groyne which has been run out
from the old sea wall, via., the " DeHavilland's Bulwark," has carried the beach along
with it, the longest groyne being about 400 feet in length, and consequently, as the
shore has gained on the sea, the line of surf has moved out in proportion ; and it is a
question yet to be solved how long tins same natural action of the elements will con-
tinue as similar works are pushed on seaward.

"5. In regard to paragraph 23, 1 cannot see that the position of Port Said and its
natural advantages added to the Suez Canal are at all analogous to those of Madras,
which are simply nil ; the attraction of the latter port being its cheapness and easiness
of access, it being an open roadstead.

M 6. I concur with Captain Taylor in some of his opinions ; yet my own opinion
is this that, if we are to have a gigantic work for the protection of the shipping, a
breakwater is the best. It is thus far a certainty — the roadstead inside of it cannot
silt up, and it will be a protection from the heavy break of the sea in a gale, when
the wind is dead on shore, which is the time of peril to shipping.

" 7. The success of an enclosed harbour is supposed by numbers to be an impos-
sibility ; at all events, it must be problematical.

* 8. I may also remark that during a gale, while a ship could run in under .the lee
of a breakwater for shelter from the heavy sea, she could not run into such a harbour
as that proposed by Mr. Parkes.

u 9. With reference to " Memorandum by the Chief Engineer " and his letter to
the Head of the Marine Department, dated 5th April, 1878, No. 128, 1 entirely agree
with his views on the subject If there is to be a harbour, it will be an imperative
necessity to have the entrance protected; by a breakwater ; otherwise in a gals the

80 FORMATION OF A HARBOUR AT MADRAS.

heavy sea will roll in, and the ships in that confined space will grind each other to
pieces, being in a much worse position than in an open roadstead.

" 10. I also entirely agree with the Chief Engineer regarding the nature and extent
of our littoral currents, and in his judicious recommendation that Mr. Farkes should
reside in Madras for a year or so to watch the currents, &c

M 11. I may remark that these are at times so very strong, that the boatmen will
not float their boats unless the strong current flag is flying at the Master Attendant's
flagstaff, which entitles them to double hire. I think this is pretty conclusive evi-
dence that these currents exist

" 12. With reference to the last paragraph of letter referred to, in the event of a
harbour being constructed, tug-steamers will be required to tow the ships in and out
of the harbour in fine weather, and it will depend on the space, which will be decided
on for the inside area of the harbour, as to the number of ships which can be berthed
alongside the jetties and moored head and stern in the basin.

"13. In conclusion, I may observe that, while I give the preference to a break-
water as a more suitable work for this port than an enclosed harbour, and while I
fully admit that it wonld alter greatly for the better the character of the roadstead, it
is yet to be borne in mind that, should any costly works be carried out, the interest
of the outlay must be provided for by an increase of rate of port dues ; and in these
days of railway progress, and consequently increased facilities of communication to
and from out-ports, is it not to be expected that, in the circumstances, a considerable
proportion of the Madras trade would too probably go elsewhere ? "

49. Remarks on the Master Attendant's Report. — With respect to para-
graph 3 of the above report, my statement of the comparative force of the sea
at Kurrachee and at Madras was based on information obtained from per-
sons well acquainted with both coasts ; bnt the principles of my design are in
no way dependent npon its being correct (see paragraph 61 farther on).

50. I have already entered folly into the subjects touched upon in
paragraphs 4 and 5.

51. With regard to paragraphs 6 and 7, it is remarkable that, con-
sidering the number of existing close harbours in all parts of the world,
the success of the principle should be deemed problematical, while a
scheme, for which there is not a single precedent to be found in nature
or art,* should be pronounced certain of success.

52. The opinion given in paragraph 8 will no doubt have its due
weight. I will only state here that it is opposed to that of every nauti-
cal man with whom I have conversed on the subject, and that, as a matter
of fact, ships do continually enter harbours similar to that I have pro-
posed in very heavy seas.

* Note.— I cannot admit the resemblance suggested by Sir Arthur Cotton between a breakwater,
a mile long, and the formations known as " barrier reefs " generally extending for many mike.

FORMATION OF A HARBOUR AT MADRAS. 81

58. Aa to Mr. Dalrymple's proposed breakwater to shelter the en-
trance, I do not myself think it would be either necessary or an improve-
ment*, and this is the opinion of most of the competent persons with
whom I have conversed on the subject ; but it is a mere matter of detail,
which may best be settled by actual trial of the effect of the entrance
without a breakwater. As to the ships in the harbour grinding one
another to pieces, I need only refer to the plan which shows how they
would be moored.

54. With regard to paragraphs 10 and 11,1 may remark that I do
not question any of the facts given me by the Master Attendant and
other competent persons as to the littoral currents. I only maintain that
they do not present any difficulty to the construction of a harbour, or to
its use when constructed. As to the nature of these currents, and as to
their having no effect whatever on the bottom outside the line of surf,
I believe Mr. Dalrymple and myself are entirely agreed. This being the
case, it is difficult to see what object would be gained by my spending a
year or so in watching currents, &c, which are already so familiarly
known to Mr. Dalrymple and others, and it is admitted have little or
no bearing on the question.

55. I entirely agree in the principle laid down in Mr. Dalrymple's
last paragraph, that an increase of port expenses would be detrimental to
the trade of Madras, but I have shown that the plan I propose, can be
carried out without any such increase.

56. Entrance to Harbour. — Having now stated the grounds on which
I venture to think that the objections to the general principle of an
enclosed harbour are untenable, I proceed to consider a point of detail
which has been made the subject of some discussion. I allude to the
position and form of the entrance or entrances.

57. Comparative advantages of one and two Entrances. — The plan
which I submit as being, in my opinion, on the whole the best, has an
entrance 150 yards wide, facing east by south. The alternative plan is
to have two entrances at, or near the outer angles of the harbour. The
one undisputed advantage of this latter plan is, that vessels could enter
or leave by one entrance or the other with any wind. The one undisput-

ed disadvantage is that, inasmuch as a sufficient space must be kept clear
in the neighbourhood of each entrance for ships to bring up alter entering

• See paragraphs 61 and 09 further an.
VOL. V. — SKCORD BE BIBS. M

82 FOBMATION OP A HARBOUR AT MA DBAS.

the harbour, the space required for the second entrance would be lost as
mooring ground.

58. For the Entrance and Exit of Steamers and Ships. — These two
considerations are inseparable from the very principles of the two systems,
and the respective evils connot be averted by any arrangement of detail.
We can only endeavour to estimate their relative value. The disadvan-
tage of the double entrance is simply this — a sacrifice of one-fifth or one-
sixth of the capacity of the harbour. The disadvantage of the single
entrance will be different for different classes of vessels. For steamers, the
most important class, it would be nil. Large sailing vessels could enter or
leave without steam power with the wind in 18 out of 32 points of the
compass. In the remaining 14 points either way, a steam tug would
probably be required. But it must be remembered that with an on-shore
wind, a large outward-bound ship would probably take a tug to get an
offing quite independent of the question of clearing the harbour, while to
an inward-bound ship, with an off-shore wind, there would be at least
smooth water and good anchorage till she could be towed in.

59. For Native Craft. — Native craft, outward-bound, could certainly
sail out of the entrance whenever they could beat off the shore, and m-
ward-bound, with an off-shore wind, they could bring up, if unable to
enter the harbour, on the more sheltered side, north or south, and either
discharge there or warp in at leisure. I, therefore, cannot estimate the
disadvantage of having only one entrance as being of much practical im-
portance to any class of vessel.

60. For protection from Seas with one Entrance.— -More importance
has probably been attached to another objection, which, however, I cannot
admit as undisputed, viz., the danger from heavy seas from the eastward
rolling into the harbour. Those who urge this objection are probably not
fully aware of the effect produced upon such seas when they enter a harbour.
They are immediately dispersed, and the extent of reduction is not, as in
the case of an open breakwater, a matter of speculation, but it is one of
exact calculation.* Captain Biden, the former Master Attendant, esti-
mates the maximum height of wave at Madras at 10 feet. Such a wave
entering the harbour would be reduced to 1 foot 9 inches before it reached
the piers or the beach. A wave 15 feet high (the maximum measured at
Kurrachee), would be reduced to 2 feet 7 inches— neither very formidable.

• Stevenson on Harbours

TOBMATIOH OF A BARBOUR AT MADRAS*

61. With two Entrances. — Whether the two entrances would admit
more or less swell with an easterly sea would depend on their width and
form. If equally accessible to vessels as the eastern entrance, they would,
I believe, together admit more sea, and the reductive power of the har-
bour would be less, as each wave would spread oyer only one right angle
instead of two right angles.

62. Effect an Seas from different Directions. — With the north-east
monsoon swell, the eastern and northern entrances would be about on a
par, but the former would have more reductive power. If the tranquility
of the harbour were inversely proportioned to the duration and force of the
wind to which the entrances are respectively exposed, the easterly one
would have a marked advantage over either of the others separately, and of
course in a far greater degree over the two together,* but the easterly seas
are the heaviest and most dangerous, and go far to counterbalance this ad*
vantage. On the whole, however, 1 am of opinion that the balance of
advantage is on the side of the single entrance facing east by south.

63. Details of Execution — Granite. — I have now to offer a few ex-
planations as to the details of the mode of carrying on the work. The
great bulk of the material required is of course stone. I have visited St.
Thomas' Mount and Palaveram to the south, and the Red Hills, Avady,
Umbatoor, and Seetapetty on the west of Madras. In the former direction
the material is granite, and might be brought in any quantity by the
Carnatic Railway now under construction, but it is so exceedingly hard,
that it would be very expensive to quarry, and would probable come out
in blocks of inconveniently large size. I, therefore, discard this source of
supply.

• Abstract compiled from Qbstrvatorf records.

Wind.

H. by W.— N., ... 1
N. by R»— N. N. &,... V
H. B. by N.| imJ

I. by Ww~— B>, ...1

L by 8.— B. S« B«t ••• }

* B. by B«, *m ~*j

* By H.*"""B»j m. ^^ ... 1

i* by w»~" S. B. w.,».« r

* W. by S»» ••• •**j

1870.

Duration, ... 1,741 hoars,...

Mean rate,

Duration, •*.
Mean rate, ~

Duration, ...
Mean rate, ...

7*2 miles,

1,134 hoars,
6*7 miles,

1,480 hours. ...
7-6 miles, ...

1871.

1871

1,218 hours, ...
6*i miles,..

1,199 hours, ..
5*7 miles, -

1,488 hours, ..
7*86 miles, ..

1,860 hoars.
7*80 miles.

1,216 hoars,
6-8 miles.

1,889 hoars.
8*4 miles.

84 FORMATIOH OF A HABBOUB AT XADBAfl.

64. Laterite. — At the other places the material is laterite, of which
the best quality would be very suitable for those parts of the work where
great hardness is not essential, such as the curved approaches to the piers,
which I propose to cany over the shifting sand near the shore, as simple
embankments of rubble stone, and for the rubble bases of the piers them-
selves. The Breakwater Committee very wisely rejected the use of this
material, as in their section it would be exposed to the destructive action
of the waves, for which it is not sufficiently hard. In my section it will
not be so exposed, and with due care in selection it may be used with per-
fect confidence.

65. Conveyance by Railway.— & branch from the Madras Railway at
Umbatoor, nine miles from Madras, running northward for about two
miles, would cut through an ample supply of this material, which the Rail-
way Company would bring to the very site of the works.

66. Trittany Granite for Concrete, — For the bulk of the concrete, I
have estimated for a better material, granite from Trittany, fifty miles from
Madras, but I think it not improbable that even for this purpose laterite
would answer, and, if so, a saving on the estimate would be effected.

67. Beach Railway.— A line of railway would require to be laid along
the beach for the conveyance of the stone to make the curved approach to
the south pier, and for the concrete blocks for the superstructure of the
pier itself, but the whole of the rubble stone for the bases of both piers
would be placed in boats (probably steam hopper barges) at the north pier,
so that after the curved approach was completed, the traffic along the beach
railway would be very limited.

68. Concrete-mixing Station and Stacking Ground. — There appears to
be no difficulty in a portion of the beach north of the Railway station be-
ing occupied by the necessary concrete-mixing establishment, and ground
for making and stacking the blocks. Branch railways would, of course,
be laid for the conveyance of materials.

69. Time of Completion. — The first operation would, of course, be the
formation of the curved approaches. These might be commenced imme-
diately, and while they are in progress, the necessary plant and machinery
could be collected. The actual building of the piers could be completed
in three years, or, say four years from the time of the approaches being
commenced.

70. Remarks on Estimate.— The estimate of £5,65,000 is, I consider,

TORXATIOH OF A HARBOUR AT MADRAS. 85

a safe one, and is based on a fair allowance for the increase of ordinary
iito, which generally accompanies the execution of so large a work. In
the event, however, of the work being placed in the hands of any other
Engineer, a new and entirely independent one should be framed by him,
but I see no reason why it should exceed mine.

71. Survey required. — Before any works are commenced, it is most
desirable that a new and detailed surrey of the roadstead should be made,
the soundings of which should be referred to a permanent mark on shore.
The level of mean sea should also be accurately determined, and where the
rise and fall of tide is so small, I think the mean sea-level would be a
better datum than that of low water. The surreys on which I have based
ny calculations and drawn my plans are rather vague, and but for the ex-
treme simplicity of the natural features of the coast, would have been
insufficient. I believe, however, that neither design nor estimate can be
materially affected by any possible corrections that may be made, but an
exact record of the existing state of things is imperative before works
which may effect a change in them are commenced.

72. Conclusion.— In conclusion, I have only once more to express my

acknowledgments of the uniform courtesy with which I have been received

bj ererj one with whom I have come in contact in the prosecution of my

inquiries and the readiness with which every information and assistance

has been afforded to me. If £ mention no names, it is because I should

not bow where to stop.

W. P.

FORMATION OF A HARBOUR AT MADRAS.

APPENDIX.

Cyclones and other Storms at Madras recorded at the Government

Observatory.

1787, llth November.

Centre North of

Madras.

1788, 7th May.

Centre North of

Madras.

1797, 27th October.
Centre at Madras.

1807, 10th December,

Centre South of

Madras.

1811, 2nd May.

Probably central at

Madras.

1818, 24th October.
Central at Madras.

1820, 20th March.

Centre North of

Madras.

1820, 9th May.

Centre North of

Madras.

1827, 7 th May.

1827, Qth May.

1827, 9th May.

Centre North of

Madras.

Wind at noon on 10th, N. Midnight N. N. W-
llth, sunrise, N. W. Noon N. W. After sunset,
violent and veering all round the compass. 12th,
sun-rise, S. S. W. Noon S. 13th, sunrise, calm.

Sunrise N. W. Noon N. W. Midnight N. W.
8th, sunrise, W. NoonW. Midnight S. S. W. 9thf
sunrise, S. S. W. Noon S. S. E. Midnight, calm.

Began from northward, veered to N. E., blew
with uncommon violence three hours ; about noon
suddenly shifted to south, and was almost as violent
as before.

Began from N., veered to Southward of E., and
slackened gradually.

Began from N., blew equally strongly from E. S.
E. and S., but details not given. Not felt 40 miles
from Madras.

Began northerly, then a lull of half an hour. Then
from south with greater fury. The most violent
storm then on record.

Commenced from N. E., veered to N., N. W. and
S. W., but at last quarter gradually slackened. More
violent to northward than at Madras.

Commenced at N. W., shifted to W. Worse than
storm of October, 1818.

Strong wind from S. E.

Early morning strong gale from N. E.

From sunrise strong gusts from E. to S. till 10 a m.
when nearly ceased. At sunset blew from W. N. W.
and during the night a gale from N. W. Subsided

FORMATION OF A HAKBOUR AT MADRAS.

1130, 2nd December.
Centre South of
Madras.

1836, 30th October.
Central at Madras.

1841, Uth May.
Centre North of
Madras.

1843, 22m* May.

Centre North of

Madras.

1846, 2MA October.
Centre Abrrt of
Madras.

1846, 25<A November.
Centre South of
Madras.

1847, 13£& October.
Pure Northerly gale,
not cyclonic.

in the morning of lOtb. This storm longer in dura-
tion, but not so heavy as preceding ones.

A stormy day, but at Cuddalore, 100 miles south
of Madras, a very violent storm.

Very violent. First from north, then a lull of 30
minutes, then with increased fury from south. Much
more severe than those of 1818 and 1820 as shown
by barometer.

A gale of extraordinary violence. At 9 a.m. N. N.
E., 10 a.m. to 5 f.m. north. Then for an hour vary-
ing from N. E. to N. W. At 6*20 p.m. approaching
a hurricane from N., at 7 to 7*80 from W. to N.
7*45 south-westerly, a violent gale. 8 to 9, S. W.
to N. W. and shifting even to 8., approaching a hur-
ricane. Thence subsided, remaining at S. to 8. W.
calm after 7 a.m. on 17th.

N. to N. W. for 24 hours previous. From 7 a.m.
till 1 p.m. continually shifting from N. W. to S. W.
and back.

Began at 11 a.m., wind W. N. W., then at 1 p.m.
due W., remained between W. and W. 8. W. till 8
p.m., force increasing to 8 lbs.* Then back to W. ris-
ing to 13 lbs. Then rapidly veered round the com-
pass by E. and 8. till at 7 a.m. on 21st, direction 8.
8. W., force 7£ lbs. Then gradually fell, direction
being 8. by W.

At 5 p.m. N. E. force 5. lbs. At 7-30, E. by N.
pressure 26 lbs., then instrument broke. At 7 a.m.
calm due 8.

During the day wind N. W. and N., for \ hour,
at 8*45 p.m. changed to E. of N. then remained
due N. for the rest of the gale having a maximum
force of 12 lbs. at 6 a.m. Subsided at 3 p.m. return-
ing N. W.

* Prom 1846 to 1 W8, tbo force of the wind is given in lbs. on a square foot. Subsequently its
Ttlocttv is given in miles per hour.

FORMATION OF A HARBOUR AT MADRAS.

1848, let November.
Light centre South of
Madras.

1850, 24th May.

Centre South of

Madras.

1851, 4th May.
Centre North of
Madras.

1858, 20/A November.
Centre North of

1864, 18M November.

light centre South of

Madras.

1865, 26th November.

Centre South of

Madras.

1872, \tt May.

Centre South of

Madras.

Began before sunrise, N.N.W. under 5 lbs. At 2
p.m. N. N. E. At 7-30 N. E. 6£ lbs., at 4} a.m. on
2nd wind E. and dropped to 1 J lbs.

At 10 a.m. light at E. by N. increasing till 1-30
p.m., E. N. E.y maximum at 2 p.m. E. 8. E. (12 lbs.)
at 4 p.m. dropped to 5 lbs. 8. E. by 8.

At 11 p.m. (3rd) 5 lbs. N. W. by N. At 3-30.
a.m. increasing in force from W. At 5*30 a.m.
maximum force 17£ lbs., direction W. At 9 a.m
dropped to 10 lbs. 8. W., diminishing at 8. 8. W.
Calm at 8.

Began at 4 p.m., direction N. N. E. (5 lbs.) At
9-30 p.m. N. E. (8 lbs.) steady till 2 a.m. 21st (12
lbs.) Then veered northward, maximum force 17 lbs.
At 4-30 a.m. N. by E. Then back to W. of N.y
dropped to 5 lbs. by 9 a.m., direction N. W.

At 3 p.m. N. by W. (25 miles) steady till 9 p.m.
Then veered to N. E. by N. and N. E., by 9*45.
Continued to increase till at 2 p.m. it was 28 miles
per hour, and it dropped from thence as wind veered
to the south.

Began on 26th at 8 a.m. from N. E. by N., speed
25 miles, then gradually increasing all day till at 9.
p.m. it was N. E. by E., with speed of 43 miles.
Then decreased as it veered to 8. E. by 6 a.m. and
thence to south, where it dropped.

Wind northerly for two days previously. Blew
steadily but with gradually increasing force from N.
to N. N. E. till midnight Then increased rapidly
up to 8 a.m., being then 53 miles, direction N. E.
By 9*30 veered to E. Then gradually working to-
wards the south, dropping to 14 miles at 8 p.m., and
then remaining steady in direction and force from
8. to 8. 8. E. for several hours.

FORMATION OF A BARBOUR AT MADRAS. 89

[Note by Editor.^-ln connection with the above Report, the following
Extract from " Thornton's Indian Public Works," in regard to this pro-
jected harbour, will be found interesting : —

" The harbour is intended to serve less as one of refuge than as a gigantic dock
where cargoes may be landed or shipped in smooth water instead of in the midst
of surf, and by means of ordinary lighters instead of Massnlah boats, an immense
deal of damage being thns prevented, and much time and therefore money saved.
It is calculated that altogether tbe expense of landing and shipping will be reduced
by at least 2«. per ton, at which rate the reduction on 275,000 tons, the assumed
aggregate of imports and exports, will amount to 27,500/. ; and it is further calcu-
lated that, in order to defray the annual expenses of the harbour when finished,
inclusive of interest at 4 per cent on its cost, a charge of very little more than half
per cent, on 6,000,000/., the supposed value of the aggregate imports and exports
will suffice. Not improbably it may be found impracticable to subject the entire
trade to this tax, which could not reasonably be levied in respect of vessels that did
not make use of the harbour, and, in that case, any deficiency in the expected
receipts from port dues might have to be made good at imperial expense. But the
Madras Harbour scheme does not depend for justification on the prospect it holds out
of direct pecuniary remunerativeness. The risks which, in my humble judgment,
may reasonably occasion some uneasiness are, first, that of the harbour (which, as
seems to be admitted on all hands, must inevitably silt up sooner or later) becoming
choked much sooner than its advocates expect ; and, secondly, that through an open-
ing of 150 yards, facing due east, dangerously heavy seas may gain admittance,
in heavy weather, much farther within the harbour than is commonly anticipated.
If, however, apprehensions on these scores should be proved by experience to be
groundless, and if the harbour be really found to answer its purpose, its construction
may then be entitled to be regarded as an enterprise in which, though it might have
ruined private undertakers, public money has been profitably expended. For, irres-
pectively of their inestimable national value as guarantees against loss of life and
property by shipwreck, the services rendered by good harbours are of the same
nature, though different in degree, as those obtained from good roads or good rail-
ways. By facilitating access to market they increase the value of produce, raw as
well as manufactured, and therefore that of land, and consequently, in a country
like India, where the Government is landlord-general, increase too, indirectly, if not
directly, the revenue of the State."

The first stone of the new Harbour Works was laid by the Prince of
Wales, on the 14th December, 1875.]

VOL. V.— SECOND SERIES. N

90 FORMATION OF A HARBOUR AT MADRAS.

Notes on the Proposed Harbour for Madras on the Plan designed by
Mr. Parkes — its defects pointed out, and remedies suggested. By Robt.
J. Baldrey, Esq. [ Vide Plate XVII].

Preface. — I am folly alive to the difficulty of my self-imposed task, and
conscious of my inability to give suitable expression to my thoughts and
ideas on a subject, the importance of which demands an abler pen than mine
to depict. Bat as nothing has been done to warn the public of the impend-
ing evils which, I believe and feel assured, will result on the completion
of the Close Harbour about to be formed on a design by Mr. Parkes, and
as the matter is of vital importance to every citizen, especially house-
holders, whose property, in the event of failure, cannot, like that of mer-
chants and traders, be removed to a more favored Port or City, I should
consider myself culpable were I any longer reticent from a feeling of
diffidence as to my powers to handle so difficult a subject, and repugnance
to give publicity to my opinions.

I should indeed be the last to oppose an undertaking which, if success-
ful, would undoubtedly enhance the value of the several landed proper-
ties which I hold in Madras, — such a proceeding would be counter to my
own interest, — so it is not probable I would publish this protest, were I
not convinced that there are reasonable grounds for doing so. Being in-
terested in the project, I was induced to study the plan of Harbour, and
not being altogether without local experience after a residence of more
than 30 years, and not entirely devoid of knowledge on Engineering
matters after a service of about 22 years under the Madras Railway
Company and Public Works Department, I was enabled to form an opin-
ion which, I regret to say, is not at all favorable to the plan, for in
every delineation of it I fail to read anything but disaster and ruin!
to our good old City. This being my conviction, I consider it nothing
but my duty to submit the matter to my fellow-citizens; and should
these statements be considered worthy their attention, it is left to them to
pursue whatever course they may consider necessary to avert the evils
threatened. Feeling that possibly a wrong view may be taken by me, I
submitted my opinions to the judgement of gentlemen whose knowledge
on nautical matters and local experience relating to the peculiarities of
this coast is unquestionable, and the result was that they concurred with

FORMATION OF A HARBOUR AT MADRAS. 91

me on every point put forward in this paper. Peeling myself thus sup-
ported in my views, 1 submit them with greater confidence to the public.

I may state, in conclusion, that I was informed by good authority, that
experienced Mariners frequenting this coast, declare, that rather than
risk their vessels being ground to pieces in a harbour which provides no
shelter from the force of the wind during a hurricane, they would clear out
and take their chance in the open sea when warned of the approach of one.

From the latter statement, together with others made to me, I would
infer that by publishing these papers, I am but expressing a general
opinion regarding the close Harbour proposed for Madras.

Prior to the execution of a gigantic project, such as the harbour scheme
for Madras, the success or failure of which would act either beneficially
or prejudicially to the Port, it is considered highly desirable, with refer-
ence to the proposed project, to obtain all the local experience possible
by inviting the residents, whose interest it is to aid, to contribute their
mite of information to the general stock. By such a procedure, much
light will be thrown on the subject, and from quarters where little was ex-
pected to be elicited.

This precaution is yet the more necessary, when able and scientific men
hold opinions of a conflicting nature regarding the proposed project, and
judging from the various reports on the subject, the question as to the
practicability of carrying out a work which would provide suitable accom-
modation and shelter to shipping in the Madras Roads appears to be a
case in point, and it would be unreasonable to ignore any information
which may help to attain the desideratum coveted, simply because it did
not emanate from a source considered to be orthodox. Any particulars,
therefore, bearing on the subject, should not be discarded, however hum-
ble the source from which they may be drawn, but be impartially weighed
and investigated, and thus the path leading to a successful termination
will be cleared of all doubts and difficulties.

In the event of Mr. Parkes' plan being carried out, the evils appre-
hended are particularized as follows :—

1st. Inundation of the Town.

2nd. Unsuitability and consequent failure as to the object for
which it is built. ,

3rd. Production of sickness.

4uk Faulty construction and imminent destruction.

92 FORMATION OF A HARBOUR AT MADRAS.

I shall therefore divide my subject under the following heads : —

Physical, Nautical, Sanitary and Construction, — concluding with my
suggestions as to how the defects may be remedied.

I shall now proceed to analyze the several heads of my subject, which
does not pretend to anything more than an earnest appeal to that rather
rare gift, vulgarly designated " sound common sense."

1st. Physical. — The features of the Coast of Madras are familiar to my
readers, and it will be plain to all, that on such a bold, straight, and
low-lying coast with strong litoral currents, any solid pier or arm pro-
jecting a considerable distance into the sea at right augles to the line of
coast will naturally arrest the progress of the litoral currents, and the
obstructed body of water will rise considerably at the, point of intercep-
tion, especially during the periods of strong litoral currents produced by
storms during the North- East and South- West monsoons ; the direction
of either of these winds will force the waves into the north or south angle
caused by the projection of the pier from the coast, and drive the waters
literally into a corner and cause them to overleap the low bulwark and
rush into the town, carrying everything before them ; and the disaster which
lately befell Masulipatam will be re-enacted.

From its lowness, Madras is subject at any time to such a catastrophe,
and any measure having a tendency to precipitate its occurrence, should
be avoided. I may here quote from Talboy Wheeler's " Madras in the
Olden Time," page 128, extract from original records : — "The sea having
" for abont ten days past encroached upon this town, and we hoping as it
" is usual, that it would retreat again of itself, forebore any remedies to
" keep it off; but now that instead of its losing, mightily gains ground up.
" on us, and that without a speedy course be taken, the town will run an
" apparent hazard of being swallowed up, for* it has undermined even to the
" very wall, and 60 deep that it has eaten away below the very foundation
" of the town — and the great bulwark next to the sea side, without a speedy
" and timely prevention, will certainly in a day or two more yield to its
" violence : it is therefore ordered forthwith that the drum be beat to call
" all coolies, carpenters, smiths, peons and all other workmen, and that
" sufficient materials be provided, that they work day and night to endea-
" vour to put a stop to its fury ; for without effectual means be used in
" such an eminent danger and exigency, the Town, Garrison, and our own
" lives, considering all the foregoing circumstances, must needs be very
11 hazardous and insecure." Then from a "General Letter" from England.—

FORMATION OF A HARBOUR AT MADRAS. 93

"We take notice of the great inundation that endangered onr Town and
"Fort, and we would have yon endeavour to prevent such future acci-
dents* • f * by raising new works as a security to their lives, houses,
"wires and children, and of all that belongs" to them. I have myself
witnessed in ordinary weather a wave break over De Haviland's bulwark
or sea wall, and sweep its way past the base of the lighthouse. Such be-
ing the case under ordinary circumstances, with the natural and unaltered
line of coast, what may not be expected should an obstructing medium be
interposed to the natural course of an impetuous current.

Mr. Parkes' Project offers just such an obstruction : the two arms or
piers which he proposes to project several thousands of feet into the sea
at right angles to the line of coast present au opposing body to the
storm currents in their natural and straight course along the shore. It
is, to say the least of it, very unwise to court danger, and that reason
alone should be a sufficient objection against the adoption of any plan
which is likely to cause loss to life and property, especially when its
ostensible object is to effect the very reverse : — as far as I have been able
to ascertain, the possibility of inundating the Town from the effects of
solid piers, projecting into the sea, has not been as yet considered by the
authorities.

The storm currents on this coast are prodigious in force and rapidity.
I am well assured of this, for I have been several times an eye-witness to
their effects. I have watched the hardy Madras boatman (than whom as

* class I have not seen more venturesome and expert swimmers) whilst
endeavouring to convey a line to a vessel about to be stranded on the coast,
on one occasion somewhere between the Public Works' Workshop and
the Ice House, when he was borne rapidly away in a few minutes by the
strong current, notwithstanding all his eel-like endeavours to gain the
shore, which he only reached somewhere between the bar and Cupid's
how, a distance of about a mile and a half. To get to the vessel, he had
to proceed a considerable distance south in order to drop down on her,
which he did, for he had admirably calculated his distance, and had
scarcely time to cast the line on board when he was swept past the vessel.
The simple circumstance only serves to show that much is to be feared
from any abrupt projection from the line of coast. It may be argued that
Hondation of the town may be effectually guarded against by erecting

* sea wall of sufficient height, to a considerable distance on each side of
*** harbour to protect the low -lying districts, but is this a contingency

94 FORMATION OF A HARBOUR AT MADRAS.

that is allowed for in the estimate ? if not, the great additional cost would,
I consider, be a serious objection, especially when a design precluding
any fear of inundation can be provided.

Such an objection cannot be charged against a work like my proposed
breakwater, for, being detached from the shore, the water cannot be pent
up to cause inundation to the town, for it admits of a free passage to the
currents between the work and the beach ; from a detached work like this,
shoaling cannot be apprehended : this is the opinion of Sir Arthur Cotton
and others (vide Mr. Parkes' Report), for the simple reason that the cur-
rents along the coaBt will drive out or scour the sand from between the
outwork and the beach, especially if the outwork or breakwater lying
parallel to the coast is not of very considerable length, the reductive
power on the waves and current flowing into passage between breakwater
and shore being proportionate to the length of passage with the squares
of its relative width.

On the other hand, it is admitted by all authorities, Mr. Parkes him-
self included, (vide his Report, paras. 14 and 15,) that piers or groynes
extending from the shore will arrest the drift sand ; the proposed har-
bour, therefore, being nothing more than two piers or groynes which,
after running out a considerable distance from the beach into the sea,
converge and almost meet ; the space between their extremities forming the
entrance to the enclosed area intended to shelter vessels : these piers will
undoubtedly arrest the sand, but not to the extent supposed by Mr. Parkes,
viz., a triangular space two 6ides of which will be formed by the pier and
shore ; for such a mass of sand will not be deposited, owing to the scoop-
ing action of the strong literal current sweeping the sands along with
it round the pier wall of harbour, which on its passage to meet the shore
again will deposit the greater portion in the mouth of the harbour, chok-
ing it up ; this is instanced in several cases where piers have been used.
Gressy describing Newhaven and the piers forming it, says : " this bar-
" bour, like others on the south coast, is greatly affected by the accumula-
" tion of beach and shingle which cannot be effectually scoured or washed
" away by any means yet attempted, notwithstanding the great indraught
11 and eddy tide which set towards the mouth, the average rise of spring-
" tide at the harbour's mouth being 19 to 20 feet, and of neaps about 14
" to 15 feet." Sucji being the case with harbours, possessing the great
natural advantage of a constant tidal scour, what can be expected in the
case of a close harbour at Madras, where there is only an occasional high

FORMATION OF A HARBOUR AT MADRAS. 95

water of about 3 feet ? Looking nearer home, I shall conclude my re-
marks regarding the effects produced by groynes or solid pier-walls by
quoting from a report to Government by a local authority : " I have," he
says, " only to state that according to our experience and my own per-
" sonal observation, every groyne which has been run out from the old sea
" wall, viz., De Haviland's Bulwark, has carried the beach along with it,
" the longeat groyne being 400 feet in length, and consequently as the
" shore has gained on the sea, the line of surf has moved out in proportion,
'' and it is a question yet to be solved, how long this same natural action
" of the elements will continue as similar works are pushed on seawards."

The above statement is by a marine authority whose experience extend-
ed oyer a period of as many years as did that of Mr. Parkes in days.

With all the natural advantages and the protection which the intended
coast of Great Britain affords for the formation of close harbours, it is
a recorded fact that numbers of far greater capacity than that proposed
for Madras suffer severely from shoaling, so much so, that a port on ac-
count of it has been abandoned, and the space once occupied by the har-
bour is now turned over by the plough-share, for agricultural purposes ;
yet it is disallowed by Mr. Parkes, except at a very distant date, and
therefore considered no- element for consideration, that the close harbour
for Madras will be affected by shoaling, notwithstanding all the facilities
afforded by the bold, straight, unsheltered sweep of coast (entirely dis-
similar to any of those of Great Britain) to the passage of litoral cur-
rents, hearing, on their unimpeded course, their burthens of drift sand
to be deposited as they speed on in the first cavity or indented space
which presents itself along the line of coast.

Mr. Parkes fixes the period of the shoaling of his harbour at the
remote date of 180 years. I fail to understand how he could have based
his calculations, as he states in his report that he has done, on the amount
of sand deposited between the groynes during a season ; for it is an un-
doubted fact that the sand is constantly warped round the head of each
groyne by the action of the currents (the very fact of the filling in of
the centre and those spaces between groynes furthest from the direction
of the current proves this); then the sand deposited, say between the first
two groynes, will displace an equivalent or be itself borne over to the
second space, and so on to the last, to be washed out on to the other side
of the beach, only to be brought back after a time by the alternate mo-
tion of the current. It is this very principle of action which takes place

96 FORMATION OF ▲ HARBOUR AT MADRAS.

in the process of harbour shoaling, and one which I have tried to explain.
This alternative warping of the sand over the pier heads of any close
harbour connected with the shore at Madras will effectually close up, if
not fill it. Mr. Parkes further remarks, that the spaces between the
groynes were not filled, as if he considered that process of filling was
not completed. I have only to say, neither will they ever be, even after
the expiration of a thousand years, if the groynes preserve their form so
long, with litoral currents, for the scooping or corroding action of the
waves will wear away the sand from the one or the other side of the
groynes according to the direction of the current, leaving on the lee side
a space unoccupied by sand ; the head of each groyne or pier will pre-
serve a clean appearance, for the sand is washed round it constantly, and
no deposit at the extremity is allowed to take place.

It will be seen by the foregoing, that after a certain accumulation of
sand has taken place, the quantity of which need not be sufficient to fill
in a rectangular space between the groynes, the surplus sand or that por-
tion which the groyne, not being of sufficient length, could not arrest,
is constantly borne backwards and forwards over the heads of the groynes
by alternating currents. Such being the case, the deposit during the
8ea807i on which Mr. Parkes based his calculation, would have been far
greater, within the same given time, had the groynes been of greater
length so as to retain or catch the surplus travelling sand; this, no
doubt, would inevitably have been the case. From the foregoing, I con-
sider that 1 have shown the fallacy of the data on which Mr. Parkes has
based his computation, and is it not now possible, that the evil of shoal-
ing (which would be a death-blow to the object for which the work is to
be executed) be much nearer to our doors than he anticipates ? This is
not only possible, but very probable, for there are no currents and surf
on the face of the globe more industrious in conveying their sandy trea-
sures to and fro, than those on the Madras coast.

To still further satisfy myself as to the fact of the sand being borne
round the head of the groynes, I have caused the surface sea water near
the head of a groyne to be caught in a vessel, and found on settlement
that there was a considerable quantity of sand at the bottom : the amount
of silt thus borne round the groynes of course would depend on the agi-
tation of the waters at the time.

It is therefore a matter for serious consideration whether so large a
sum as 56£ lakhs of rupees should be expended on a work, the plan of

FORMATION OF A HARBOUR AT MADRAS. 97

which, as far as I hare shown, promises nothing more than disaster by
inundation and the defeat of its object by shoaling.
I shall now proceed to view the subject from a nautical point.
2nd. Nautical. — Spots sheltered by nature hare, as a rule, been
selected for harbours, bat the Madras roads do not afford the slightest
protection from the very winds that are most destructive to her shipping.
Eren with the most ordinary high winds, danger, it is, apprehended, will
be experienced by vessels attempting an entrance into a harbour of the
form proposed by Mr. Parkes, who in his report states, that Mr. Robertson,
Harbour Engineer for India, is of opinion that vessels can enter and quit
more readily from behind a breakwater than through the one entrance of
a harbour. This appearo to be the general opinion of nautical men fre-
quenting this coast, and who are aware of the heavy seas to which our
Terr unsheltered roadstead is exposed.

I shall quote from several statements made by experienced mariners.
Captain J. D. Oaby, of steam ship " Khiva,9' says :~ " The force of the
u sea against the pier heads " (of the proposed harbour) " with any winds
M from the Eastward, and the eddies caused thereby, a vessel would pro-
" hably lose her steerage way, and unless the engines of the steamer, or the
" tog towing the sailing ship are very sharply worked, she would most
" likely get damaged against the pier, or else run into a ship lying at the
" buoys before she would recover herself."

From Captain J. H. Atkinson, Superintendent, British India Steam

Karigttion Company, Calcutta : " The currents would at times run

tt strongly across the harbour mouth, and good judgment with local

M knowledge would be required to avoid being set on to either pierhead ;

"as having to bring up in a comparatively short distance, the slow

a rate of speed necessarily maintained would give time for considerable

u drift, the current acting on the length of the vessel."* * * "That the

" sdrantage to be derived from two mouths is, that they would probably

" afford amore certain exit from the port, should the action of a cyclone

" storm wave cause damages to the sea wall, and by that or other means

" drift debris which might close entrance."

From Captain T. Black, Superintendent, Peninsular and Oriental Steam
Navigation Company, Southampton : " The majority of those I have con-
M stilted, and with whom I myself coincide, think that a long breakwater
" would be more suitable of the two, (enclosed harbour and breakwater,)
" the idea being fostered more by the nautical than the commercial aspect

VOL. V. — SKOOHD SERIES. O

98 FORMATION OF A HARBOUR AT HADRA8.

" of the question. * * * * Vessels arriving or putting to sea would also be
" able to do so with greater facility behind a breakwater than going in or
" out of a close harbour. To the mail steamer of this Company, we think
" a close harbour, such as Mr. Parkes advocates, would necessitate a certain
" amount of risk while entering at night, small of course if there were
" light and the water smooth, but considerable with a strong wind and a
" high sea, and the difficulty of bringing up a long steamer in the compa-
ratively small area which Mr. Parkes* plan shows, would be great, sup-
" posing that a moderate number of ships were already at anchor inside, and
" the steamer were obliged to enter with a good way on her to secure steer-
" age. * * * I think great weight should be attached to Captain Dalrym-
" pie's remarks, that during a gale a ship could run in under the lee of a
" breakwater for shelter from the heavy sea, while she could not run into
" such a harbour as that proposed by Mr. Parkes, and that in such a bar-
" bour the heavy sea would roll in, and the ships in the confined space grind
" themselves to pieces, being in a much worse position than in an open road-
" stead. In point of fact, Captain Dalrymple, Master Attendant at Madras,
" evidently thinks that a close harbour at Madras would be most dangerous
" in cases when shelter would be most required ; and I personally am greatly
" inclined to coincide with him." Mr. Parkes himself acknowledges in para.
81 of his Report : " I have no hesitation in saying that a roadstead exposed
" to the most prevalent and strongest winds, even irrespective of the direo
" tion of the heaviest seas, cannot be considered to be effectually sheltered."

The foregoing statements need no comment from me ; they speak for
themselves, and are to the point. No harbour in Madras with one en-
trance, and that facing East by South, will be accessible during the pre-
ponderating high winds from the North-east.

3rd. Sanitary. — Under this head the effects which will be produced
by a close harbour at Madras will now be considered.

It is always thought to be a matter of the greatest importance to adopt
necessary measures for the effectual scouring or washing out of harbours,
to rid them not only of silt, but of the accumulated filth from shipping,
&c. The indraught and ebby tides (which are considerable in most har-
bours, those of Bye harbour being 23 feet spring tide and 14 feet neap)
and tidal rivers, are taken full advantage of to effect this great desidera-
tum, for without such means a harbour would be soon rendered useless,
and would further prove a source of pestilence, — in fact, the plague-spot
of the Port. Subsequent to my consideration of this material point, my

P0R1IATI0S OF A HARBOUR AT MADRAS. 99

views were corroborated by the following statement by Captain J. H.
Taylor, R. N. R. : — u The landing place at Colombo, thongh having the
" advantage of the weak scour, is pestiferous from the mere decomposition
of the spilt grain cargoes and general accumulation of matter." Captain
W. Stewart, commanding steam ship " Indus" writes :— " There is one
" point to which no reference is made, viz., what will be the sanitary state
" of such a closed harbour? I suppose, if necessary, some opening could
" be left to ensure all accumulation of impurities being carried off by pre-
u railing currents."

This important point appears to be entirely omitted in Mr. Parkes' plan,
and, as it is argued by him when describing the reductive power of his
harbour, that a wave 10 feet in height outside the harbour will be reduced
to a wavelet 1 foot 9 inches on its entrance into it, no scour then can be
obtained from such a source, and the only effect which it is expected to
produce will be the deposition of everything abominable on the shore
within the harbour ; and in the event of the harbour's mouth being closed
up with sand, the effects of stagnation, together with the accumulated
impurities, will render it under a tropical sun, in reality the plague-spot
of Madras, to remove which extraordinary measures, at an enormous cost,
will have to be resorted to. Serious inconvenience will not at first be ex-
perienced, but after a few years the accumulation of filth, owing to the
small rise and fall of the sea, will soon make itself apparent, and discern-
ed by more senses than one. This state of things would be highly objec-
tionable, when it is considered that the harbour will be contiguous to the
most thickly-inhabited part of the city — Black Town.

Those who resided in the Fort some few years ago, will not easily for-
get the overwhelming stench which evolved from a ship, with a cargo of
rice, that was stranded somewhat North of the Fort ; it was simply so
abominable, that it at once awoke the proper authorities to unwonted
energy, and the decomposing grain was bundled helter skelter and com-
mitted to the " oozy deep," and if I remember rightly, one or two of the
coolies died whilst clearing the vessel. Residents who were present on
the above occasion will be able to form some idea of the nuisance des-
cribed by Captain Taylor regarding the landing place at Colombo. I
have frequently noticed grain washed along the shore which probably was
lost during transmission to and from shipping ; this, if not cleared away
by the current but enclosed instead in an almost stagnant pool, would,
with other matter, in the space of a few years, convert the harbour into a

100 FORMATION OF A HARBOUR AT MADRAS.

large cesspool. It is evident from the foregoing, that it is very necessary
to so design a harbour as to allow of its being effectually scoured by the
means which nature offers ; such can be effected, and I shall endeavour to
explain in its proper place, how it can be carried out without additional cost.

The " Silvery Cooum," although having the advantage of being flushed
out by freshes once or twice during the year, yet exhales effluvia at times,
during the dry season, the most noxious and life-poisoning. What will
then be the condition of a close harbour after the lapse of a few years
without any such advantage? The cost of diverting the sewers from
emptying themselves into the close harbour is also another item which will
necessitate a considerable outlay ; this can also be avoided by an arrange-
ment which I shall suggest. * The objection to a close harbour for Madras,
from a sanitary point of view, is serious, and should be sufficient to arrest
the attention of the authorities, for what advantage would it be, supposing
even that the harbour afforded all the security to the shipping which is ex-
pected from such a work, if the inhabitants of a thickly populated city,
and particularly those located in the leading Mercantile houses in Madras,
situated on the North Beach, were subjected, by their close proximity, to the
baneful effects of impure atmosphere generated by the nuisance described.

4th. Construction. — From long observation of the progressive settle-
ment of the boulders of stone used in the construction of the groynes
on the beach, and from the gradual disappearance of immense quantities
thrown into the roadstead by Captain, now Sir Arthur Cotton, with a
view to the formation of a breakwater/ I am led to the conclusion that
stones loosely precipitated into the sea, with no cementing agency to
bind or connect the stone or rubble into a compact mass, will, in the
course of time, be scattered by ground swells and currents, and indivi-
dually gravitate and be lost in the sand. Such being the inference I
have drawn, I am of opinion that the loose rubble intended to be depo-
sited to form a base, on which it is proposed to erect the concrete-block
wall of Mr. Parkes' harbour, will effect anything but a solid foundation
for the intended superstructure. This is the inore forcibly conveyed to
the mind, when it is considered that the pier or sea-wall proposed for
Madras, is precisely on the same principle of construction as that just
completed for the harbour at Kurrachee, and which has already given
way.

• This mound of ■tone was many yean ago so near to the surface, thai It was considered danger*
ons to shipping, and buoys had to be moored about it to iniinatft the spot. It Usaid ^hf>t very
little of the once great heap is at present to be

PLATE XVII.

PLAK OF THE TOWN, AND ROADSTEAD OF MADRAS.

(Skewing lit Haibaxr propottd by Mr. R. BaJdrafj.

F0BMATI0H OF A BARBOUR AT MADRAS. 101

Remedies proposed. — In preparing a design for a suitable harbour for
Madras, 1 have kept in view the objections to both the close harbour
project and that of the breakwater, and endeavoured to keep clear of
the defects or doubtful points of each, selecting the unobjectionable or
good characteristics which both possess, and which, if combined, would,
I feel confident, afford suitable shelter to the shipping in the Madras
Roads, and thus avoid all the dangers apprehended from the adoption
of either the close harbour by Mr. Parkes, or the breakwater.

In the preparation of my plan, I have avoided the introduction of any
construction having its origin at, and projecting from, the shore, in order
that sand may not be conducted or borne by the currents from the beach
along its extent into the harbour and thus shoal it up, and further that
there will be no possibility of inundating the town, by avoiding the in-
terposition of an arm from the shore, extending several thousands of
feet into the sea. Taking advantage of the currents and adapting them
to that end, I have secured a sufficient scour or circulation of the water
to keep the harbour free from impurities and consequent danger to pub-
lic health. The openings which will admit the necessary scour, will at
the same time provide a double entrance to the harbour, a point consi-
dered to be of great importance by nautical men. By this arrangement,
easy ingress and egress is also secured without any loss in mooring
space, as in the case of Mr. Parkes* arrangement consequent on position
of entrance.

The form of harbour which I suggest, will, by shutting out the sea
on the North, East and South sides, protect shipping from the heavy
seas from the North-east, East, and South-east directions, well known
to be most destructive to shipping, — provision is also made to protect
the shipping from strong winds. In rough weather it will afford ample
mooring space for twenty ships, and in fair weather double that number ;
whereas in that of Mr. Parkes' plan, only thirteen at any time can be
accommodated ; this is done without any additional cost, for the length
of the sea-wall which I propose is only 8,000 feet, whilst that of Mr.
Parkes is, including the shore extensions, 10,000 feet. If it is proposed
to accommodate only thirteen ships as in Mr. Parkes' plan, a considerable
reduction will be effected, and that too on the more expensive principle
of construction which he has adopted.

Reporting the capacity of his harbour, Mr. Parkes says : " If the ships
" were more closely moored, so as to swing clear of the next ship's

102 FORMATION OF A HARBOUR AT MADRAS.

" mooring, bat not of the entire circle she would describe in swinging,
"the number would be increased three- fold," a calculation which will
make the capacity of the suggested form of harbour 120 vessels in fair,
and 60 in foul, weather.

The cheapest cementing body I can think of to bind the rubble, is
good stiff clay, which can be obtained in abundance, and at an exceed-
ingly low cost. The non-percolating and adhesive qualities of clay are
well known. This mixed with the rubble in a proportion that would be
sufficient to fill in the interstices of the stones, and, in the course of
deposition, held together in large coarse sacks, would thus deposited,
form a mass, that will, I feel assured, become the more compact by
settlement, a result which cannot be expected under similar circumstances
from a concrete structure.

The average dimensions of sea-wall proposed by me are as follows :—

Perpendicular, 50 feet, which will carry it 8 feet above high sea level.

Base, 120 feet, top or platform, 24 feet.

These measurements will give a natural slope of 45 degrees on each
side.

The core will be of laterite rubble, one-fourth of the bulk of which will
be composed of stiff clay to fill up the interstices and bind the work to-
gether.

The core thus formed, will be preserved from the corrosive action of
waves and currents by a casing of granite boulders, 6 feet in thickness
over the whole mass.

Such a massive structure would present a more effectual bulwark to
the buffetings of storm waves, than would be offered by the more expen-
sive but less massive one, proposed to be carried out by means of concrete
blocks.

The wall proposed by me will be 8,000 feet in length ; so the total
bulk, according to the foregoing section, will be 1 ,026,296 cubic yards ;
the component parts of which are to be

Rabble, 611,556 cubic yards, at Rs. 2-8-0,* ... Rs. 15,28,890

Clay, 208,852 „ „ „ 0-8-0, ... „ 1,01,926

Granite boulders, ... 280.888 „ „ „ 4-0-0, ... „ 11,23,552

Total balk, ...1,096,296 cubic yards. Total Ra. 27,54,868

leaving a balance sum of Rs. 28,95,632 out of the sum sanctioned for Mr.

• The rate at which the harbour world is at present supplied with laterite rabble from the quar-
ries at Amlmtwr is, inclusive of Bailway charRes, about Rs, 2 to 8-8 per cubic yard deposited into
the

FORMATION OF A HABBOUR AT HADBA8. 103

Parkea' harbour, to be expended in providing shelter to the shipping
from winds, extension of present screw pile pier, plant, coarse sacks, esta-
blishment, contingencies, &c.

The piles intended for the extension of the present screw pile pier can
be employed daring construction of the sea-wall for the purposes of a
jetty to convey material from the beach opposite the Railway station at
Royapooram to the northern extremity of the proposed sea-wall, from
which point the work can be commenced.

Farther details regarding labor need not here be entered into, nor do
they require description as they are well understood.

The objections to a close harbour foe Madras are serious in the extreme,
and at best to use the words of a local Marine authority : — " The success of
"an enclosed harbour for Madras is supposed by numbers to be an impossi-
bility; at all events it must be problematical.'1 As for the breakwater,
unless it extended a considerable distance parallel to the line of coast,
(which could only be effected at an enormous cost), it would be of no
practical use, for the vessels would be driven from their moorings by
storm currents of a north-easterly or south-westerly direction. This is
obriated by the large area enclosed by my form of harbour, the force of a
storm current would be dissipated by having to spread over such a con-
siderable extent of sheltered space, and a wholesome scour will be the
nworable result. This reductive power will be most advantageous for
bite, for they may ply at any season, if there is even any necessity for it,
°r as it can be seen by reference to the plan, the pier is proposed to be
^tended to the most favorable point to enable shipping to lay to for the
Purposes of loading and unloading.

I consulted a Government Marine Authority as to the distance vessels
could approach the shore with safety ; he considered that a vessel could
approach to about 500 feet off the pier; this is a distance of 1,500
feet from the shore, but I have allowed 3,400 feet from the shore to the
terminal points of the proposed sea-wall, thus giving ample space for
egreg8 and ingress to vessels in any weather. This distance from the shore
U the more favorable, as there is no shifting sand beyond this point, the
W of the sea there being clay. ( Vide statement of Government Diver,
Breakwater Committee's Report).

Summary. — The form of harbour I propose will then avoid

Inundation of the Town.

104 FORMATION OF A HARBOUR AT MADRAS.

Shoaling.

Additional ill-health to the city.

Disaster to vessels from insufficient entrance and from want of shelter
from strong winds and exposure to heavy seas ftom east.

Advantages to be derived by the adoption of the form of harbour
proposed by me.

Mooring apace. — Considerably more area is provided for mooring
vessels, probably all that will ever be required, and at less cost than that
proposed by Mr. Parkes.

Scour. — A sufficient scour or washing out of the harbour is obtained
by the passage of the currents through the two openings intended for
entrances.

Two entrances. — An advantage considered of great importance by
nautical men.

Protection to shipping. — Great storm waves from the East run dead on
shore, and are considered the most dangerous to shipping ; it has been
therefore a matter for particular consideration to provide against such
a contingencyf which is effected by entirely shutting out the heavy seas
from that direction.

Beady conversion into a close harbour should there be any necessity for it.
•—This can at any time be effected by continuing and joining the North
and South walls with the shore, whereas in the event of Mr. Parkes'
harbour proving a failure, the possibility of converting it into any other
form will be precluded by the extension of his walls from the shore.

Cheapness. — A harbour of far less cost than that proposed by Mr.
Parkes can be carried out, even if constructed with the expensive mate-
rials he proposes, if accommodation equivalent to that provided by him is
only required.

Future extension. — Should this ever be required, it could be carried
out by constructing only two sides, either to the North or South of the
proposed harbour.

In conclusion, I trust I have given an intelligible form to my ideas on
this subject, and by cautiously steering clear of the strong objections to a
Breakwater or Close Harbour as unadapted to the requirements and
peculiarities of this coast and combining the good points in each, I have

realised a form of harbour suitable for Madras.

R. J. B.
Ritherdon Road, "I

Egmore, 23rd Nov., 1875. J

n.iTE ZVIU

IMPROVED METHOD OF WORKING BULL'S DREDGERS. 105

No. CLXXXVIII.

IMPROVED METHOD OF WORKING BULL'S DREDGERS.

[Vide Plate XVIII.].

By W. Bull, Esq., Resident Engineer, Oudh and Rohilkhand Railway.

Description of an Improved Method of working the larger sizes of BulVs

Dredgers.

Hitherto considerable difficulty has been felt in handling the larger
sizes of this machine when full. This can be entirely obviated by
having a Bhort supplementary chain attached to the dredger, as shown
in Plate XVIII.

Where a double action steam crane is available, as is often the case in
harbour and other works, the dredger should be lowered by means of
the second chain above alluded to, which would take the place of the key
in keeping the jaws of the machine open ; the chain attached to the arms
being kept slack. On reaching the bottom, the dredger can be quickly
filled by alternately patting a strain on to the two chains, sufficient to
partly close and open the machine without lifting it. When filled it
should be raised in the ordinary way, the lowering chain being hauled up
at the same time, but kept slack. The dredger having been brought over
the spot where it is desired to empty it, the lowering chain is tightened
and the raising one slackened. It then immediately empties itself, and
is ready for lowering again without the necessity for applying manual
labour in any way.

If a double action crane be not available, the dredger may be simply
emptied in the same way, by having a chain with a hook fixed in the
proper position, but not attached to the dredger. When it is brought

VOL. V. — SECOND SERIES. P

106 IMPROVED METHOD OF WORKING BULL'S DREDGERS.

up fall, by fixing this hook into the ring in the middle of the short sup-
plementary chain and slackening the chain attached to the arms, the
same result as before described will be realized. In this case the key
must be fixed when emptied.

The short chain attached to the upper edge of the two halves of the
dredger may be dispensed with, by having a double end to the second
chain with a hook on each to fix into a hole on each half of the machine.

By the arrangement thus described, machines to bring up a ton of sand
or mud at each operation may be worked with ease. It is of course
quite distinct from the machine itself, and can be fitted at pleasure.

W. B.

CONTINUOUS UNIFOBM BEAMS. 107

No. CLXXXIX.

CONTINUOUS UNIFORM BEAMS.

[Vide Plates XIX. XX. and XXI]

By Cast. Allan Cunningham, R.E., Hon. Fell, of King's Coll., Land.

Preface.— The treatment of the Problem of Continuous Uniform Beams here adopt-
ed is different to that hitherto employed in English Treatises. The whole Theory
is here* made to depend on the Theorem of Three Moments, from which the
Moments of the M Re-action-Conples ", and thence the " Shear-Re-actions " are readi-
ly found. This reduces the question to a form almost the same as that of a Bimply
"Supported Beam ". Integral Calculus is required only to establish this Theorem :
—with its aid, Cases of Continuous Uniform Beams are solvible by elementary Algebra
end Geometry. In preparing this Paper, the object has been kept in view of pre-
smtrag all the final Results in a form of immediate use to the practical Engineer.
Accordingly Tables have been prepared exhibiting (in an algebraic form) the values
of the Integrals occurring in this Paper for all the most nsefnl cases of practice.

[The usual procedure has been to investigate only the Case of uniform load and
to integrate the equation of the Elastic Curve specially, for each Case of Beam of
two spans, three spans, &c, and thence to seek the " Total Re-actions " of the Sup-
ports as the primary unknown quantities. This method is open to the objections :—

1°. No one investigation is intelligible to a Student not familiar with Integral
Calculus.

2°. It is not susceptible of generalization.

8°. The choice of the " Total Re-actions" as the primary unknown quantities is
unsuitable, and greatly complicates the question].

Notation. The Notation used is uniform with that of the Author's Manualf of
Applied Mechanics.

1. Continuous Beams. — A single Beam covering several Spans

*ari resting on several Supports is styled a Continuous Beam or Girder.

In rigid material, the Pressures on the several Supports (or Re-action of

* This Method has been adopted from Vol. TH. " of the Goon de Mecaniqne Appliqaee " of the
"Itole Imperiale dee Pouts et Chantsees" by M. Bresse, 1865. The whole of the Results, however,
h*ve been prepared specially for this Paper .

t This Paper is embodied In Part II. of the Manual just being published.

VOL. V.— SBCOND SERIES. Q

108 CONTINUOUS UNIFORM BEAMS.

those Supports) would be strictly indeterminate when there are more than
two Supports, because there are only two equations of equilibrium between
them, viz.,

Sam of Re-actions = Total Load, - ^. M (la>

Sun of Momenta of the Re-actions ) I Moment of the Loads about I rUv

about any axis, J — \ same axis, | ^ *

In elastic material, however, the determination of these Re-actions is a
perfectly definite Problem for material whose elastic properties are known.
The solution depends, therefore, ultimately on the fundamental law of elas-
ticity (Hooke's law) from which the equation of the Elastic Curve is
deduced.

The continuity of the Beam enables the weight of the Spans adjacent
to any particular Span to supply Re-actions at the two vertical end sec-
tions of the latter which tend to reduce the Transverse Strain (Deflexion),
and therefore also the (longitudinal) stress-intensity which a given Load
would cause on that Span if discontinuous.

This is of course a great advantage in Construction : the investigation
of the Stress in a Continuous Beam is therefore of considerable importance.

It is easy to see in a general way that the effect of the continuity is to
throw the Elastic Curve into a sinuous form, usually convex upwards
over the Supports, and concave upwards near the centre of each span,
these portions being separated by points of inflexion, of which there are
commonly two in each Span, so that each Span is as a rule in the condi-
tion of a Supported Beam between the inflexions resting on two Cahti-
levers. It is easy also to see,
that under particular conditions
of Load, two or more points of
inflexion may coalesce, and one
or more of the usual curvatures be effaced. As a general Rule, however,

it is clear that

1°. A segment concave upwards between two inflexions is precisely in con- 1 _ .
dition of a SUPPORTED Beam under its actual Load, J

2°. A segment convex upwards from an inflexion to a point where the'
Elastic Carve is horizontal is precisely in condition of a Cauti-
levbb under its actual Load, together with a concentrated Load at
its free end (the inflexion) equal to the Shearing Force at that point }(21X
Two such Cantilevers necessarily occur together, separated at
the horizontal point, which is equivalent to the fixed end of a
Cantilever, * ~ ••........J

2- Shear-Re-actions, Re-action Couples, Total Re-actions.
—Consider any one span (A'A") of a Continuous Beam. It clearly

CONTINUOUS UNIFORM BEAMS. 109

differs from a similar, similarly loaded Supported Beam solely by reason
of (he continuity at the Supports (A', A"). The material of the adjacent
Spans is thus enabled to apply certain Stresses at the ends A', A" of the
Span A'A*, which affect the shape of its Elastic Curve.

By elementary Statics, the whole of the External Forces acting on the
Beam A'A* at its ends A', A" are equivalent to a certain (vertical) Re-
sultant Force applied at A', together with a certain Couple, and to a
certain (vertical) Resultant Force applied at A", together with a certain
Couple; the Resultant Forces and Couples being of course all in the
" plane* of solicitation ".

The Resultant-Forces and Couples are clearly of the nature of Re-ac-
tions— as affecting the span A'A" under consideration; and the two
Resultant-Forces are clearly the Shearing Forces at the ends of the Span
A'A". For these reasons it is convenient to style them the Shbab-

Rb-actions, and Ra-AOTioN-CouPLBsf of the Span A'A".

[Obterve that the Shkar-Rb-actions are the complete Re-actions applied to the
Span A'A* at its ends, bat are only partial (not Total) Re-actions of the Supports
A', A", see Art 12].

It is convenient to use the following notation :—

R'9 R' the Shear- Re-actions at A', A".

M', M" the Moments of the Re-action-Couples at A', A".

F the Shearing Force 1 at any point whose abscissa is of, or x"

M the Bending Moment J (measured from A' or A", respectively.)

Ry B*9 F, At the corresponding values of the similar quantities in the

span A'A", if discontinuous,—

By the above notation it is clear that —

u The Resultant effect on the span A'A* of the continuity is simply the ap- ]
plication of additional external Forces and Couples at the ends, viz.,— \ (3).
(R' - R) and M' at A' ; (R* - ST) and M* at A*," J

[In using these quantities, care must of course be taken to apply them with the
proper algebraic signs].

Great use will be made of this principle in the sequel.

It is clear also by Elementary Statics that : —

(R' + R") = R' + BT = Sj w, (or Total Load on A'A0).... (4) ;

also, taking Moments round A', A" in turn,

M' = M' + (R' - 20*; M' t= W + (R" - BT) I, (5).

3. Shearing Force.— By the very definition of the term it is clear that

• M Flam of solicitation". This term 1b applied to the Load-plane or longitudinal plane of sym-
metry of the Load, which should also be a plane of symmetry of the Beam.
t The term " Btrest-Goaple " has also been applied to these Couples,

110

CONTINUOUS UNIFORM BEAMS.

Ps'B'-lfwa- (BT - 2f w) (6),

= R'_JR'+JF=-R'' + jR* + F, (7).

[It is easily seen that these expressions are equivalent].

Again, let F', F" be the Shearing Forces at the ends A', A" proper to
the span A' A".

As already explained (Art 2), these are equal to the Shear- Re-actions
at A', A" ; hence by the convention* as to the sign of a " Shearing Force "

F = R'; F as - IT, (8).

4. Bending Moment. — By the very definition it is clear that at

any section of,

M = M' + (R' - If). *' + Jf, (9>

Eliminating (R' - R) from (5), (9),

ZM-a?M* = (J--aOM' + IM,

whence, M = -y.M* + £.M' + M, (10),

a remarkably simple expression for M, which admits of simple interpreta-
tion, for it is equivalent to

M= {M' + ^.(M"-M')} +M, (11);

now, if in Fig. 1, A' m', A" m", Fig. 1.

be plotted upwards representing
M', M" on a scale of moments,
then the length Pro clearly
represents the quantity

{M' + |L(M"-M')}

so that the straight line ml m" is the graphic representation of the
excess of M over If , t. e., of the difference of actual Bending Moment
(M), and what it would be if the span were discontinuous (M).

It is easy to see that the very steps by which the following relation is
usually established (see any Work on Applied Mechanics) in the case of
" Supported Beams" are really applicable to all Beams, so that in the
present case also,

a TUT JUt

(12).

*M = F,oi4£ = F,

A • ' dx

5. Maximum Bending Moment— The Bending Moment in a
Continuous Beam has usually one positive maximum in each Span, and
one negative maximum at each Support, or more strictly one maximum
between every two inflexions, viz.,

* Of the pair of Shearing Forces at any section, (one on either side,) that on the right of the
section will be termed the " Shearing Faroe", that on the left the M Shearing Beelstaooe"; they aie
denoted by P, ^, respectively.

CONTINUOUS UNIFORM BEAMS. Ill

(I). One positive maximum in each segment of the Elastic Curve which \ n«v
is concave upwards (like a Supported Beam), J

(2). One negative maximum in each segment of the Elastic Curve which I nMV
ia convex upwards (like a Cantilever), J

These iwa^imnm values can generally be found by solving the equation

™= 0, or P = 0 (14),

which gives the abscissa of the section required. The value of the maxi-
mum Bending Moment is then at once found by substituting that value
of the abscissa in the general expressions (9, 10, 11) for M. The values
thus found are usually positive maxima, and are then conveniently
denoted by* M0.

But the Bending Moment is also commonly (not always) a negative
maximum at each Support because the segments of the Beam on either
side of each Support are usually in condition of Cantilbvbes. Its value
at the Supports is, of course, always the same as the moment of the Re-
action-Couple (M' or M").

6. Theorem of Three Moments.— Bresse's Theorem-)-.— This
important Theorem reduces the whole Theory of Continuous Uniform
Beams to a form solvible by Elementary Algebra, by furnishing an alge-
braic relation between the Re-action-Coaples at three successive Supports.

[ The investigation cannot be effected without use of Integral Calculus. The
Besult, however, (21,) is all that ia required in practice. Tables of the values of the
Integrals in this Result, and in those derived from it are provided herewith, so that
the Result itself can be used at once by the practical Engineer without requiring any
knowledge of integration.]

Fig. 2.

« 1?- * iL _>

—I Z z —

At At A,

A], A.J, A, are any three successive Supports.
M], M2, M, are the Moments of the Re-action-Oouples at A19 A*, A,.
M the Bending Moment at any section whose abscissa is x.
A2 the origin ; a horizontal line through A i, the x-axis.
x*, x, tf are abscissa) measured from AI9 A*, A„ respectively.
vlf v2i v„ the ordinates of the Elastic Curve at Al9 A* A„ after the straining action

it compUtc,
rl9 r* r, the tangents of the inclinations of the Elastic Curve at Ab A j, A*.
t , I* the lengths of the spans, As A^, A, Ar c = semi-span.
The equation of the Elastic Curve applicable to any Beam whatever, gives—

* This notation is intended to show that thoy usually occur near the middU (£ = 0) of etch span.

* This Theorem is duo to M. Bresse, and is published in Vol. III. of his " Cours de Mocanique
AppliqoeV'

112 CONTINUOUS UNIFORM BEAMS.

Integrating and observing that -j- = r„ when * =s 0, and that in a Uniform Beam

(to which case this investigation is limited) I is constant,

m(s - r«) =/*** <16>

Integrating again, and observing that v = v^ when # = f; and ss o2 when x = 0,

= 1'./"'***- /*'** f*Ud*.d*

'' (r - «r) M rtr (16>

esf1 tf M . sir, -- (17>

|This last form is obtained by changing the origin to Aj, which be it observed, fe«w
M unchanged],

Introdncing the general value of M from Result (11), the /, M', M#, of which be-
come /', M], Mj—

».(^ - «2 - **0 -/][ * { M, + i(M, -Mj) + if } Ar*

s * /* Mj + i .J* CM* - MO +y* r «• if <{*' ......... (18).

cb * /"M, - I /"Ma - l/*V». JaV (lfti).

[This last Result is obtained by observing that after the integration by parts M
vanishes at both limits (*' = 0, or f), and that as in Eq. (12), dM -5- «V a= *•].
Applying a similar process to the other Span A* A,,

EI (*, - »* + r^O = *'"• M, + J /'». M* - jy*1* aP.F4kf~JBM>>

the absciss® («*) being measured from Ar
Writing the abbreviations

K'=y^£.2W, K'=J^£.F<W (30),

and eliminating r$ from Equations (19a, 6) there results,

M1r+2M,(r + O + M,r«8(K' + K0 + 6Blj|l-«9(p+J)+^},(21).

This Basalt (21) is the important Theorem of Three Moments : it gives
a simple linear relation between the Moments of the Re-action-Couples
at any three successive Supports (of a Uniform Beam), two easily calcu-
lable integrals (K', K"), — (see Art. 8 for a Table of their values), — and
the levels (yl} v|9 *„ which are supposed given quantities) of those Sup-
ports after the strain is complete.

The importance of this Result consists in its being a linear Junction
of only three of the sought quantities (M,, M,, M„ &c). Thus in ft
Continuous Beam of n spans its repeated application gives a system of
(n — 1) simple equations, each involving only three of the sought Mo-
ments, (which are of course (n + 1) in number).

CONTIGUOUS UNIFORM BKAHB.

113

Hence, if any two of these Moments can be determined a prion, the
rest can be found by solution of the above (n — 1) simple equations.

7. Thbobbm of Thrxb Moments fob Bigid Supports.— The most
simple, and practically most important, case is that in which the level
of the * neutral surface9 is maintained constant over the Supports— (by
their rigidity)— in which case all the quantities vv vv vs) &c., vanish, so
that the Equation of Three Moments (21) becomes

m, r + 2 m, (r + o + m, r = s (K' + k*) (22).

8. Reduction of the integrate.-- The values of the integrals (k', k*) are re-
corded below for the most useful cases in practice, so that bj help of these results,
the important Theorem of Three Moments (21, 22) may be used at once without re-
quiring any knowledge of integration.

The following Table contains the values of the quantity :—

K =J* ~ . F . cfc, «: (23),

for the most useful simple cases of load-distribution. It will suffice to change I in
the values of K below to 1 9 f to give k', k" as required. Also it is obvious— from
the meaning of integration — that for any combination of Loads for which the
values of K are K], K2, &c, for each separate Load,

K =s K, + K, + K, + &C as 2 K „ ......... (24),

or, The value of Kfor acorn-) = (The
bination of Loads, 3 I fo

sum of the values of K

for the partial Loads,

(24A).

Load

[8panAB = J; Athe outer Support, B the middle

Support] •

Value of K

-/■?*

[Origin always at A, the outer Support].

Single Load (— W) at distance *\
from A, #2 from B; a^ + dfc = J

}

Single Load (— W) at centre of span
Equal Loads (— w) distant wl from the
ends A, B.
Uniform load (— w) over whole span

Uniform load (— w) over segment AP,
AP =*i, (HP sz *t unloaded),*! + w> as I

Uniform load (— w) over segment BP
BP = *& (AP = «t unloaded)

(« — 1) equidistant equal Loads (- w)
cutting the span (I) into n equal segments

jiw 3- (tf-P), or

— jwP.or — ^w«*
w *, (», - 0

— ^ vP , at — | w if

(P - iV

-A

-T^.w.^(2/-^)«

>w, ,„ P,or-w. — — e*

12 *

Oautiov. In using this Table, observe that the origin A is ahraye at tto outer 8 npport {i.e.,
AiforspaaAi A^ and A3 for span A, A*), and B at the middle Support (i«.f A, in eat of three
A« A, A3), so that the dlstanee *\ = AP of the Tabular Basalts,, is always measured from outer
Support (A| or A3).

H4 CONTIGUOUS UNIFORM BEAMS.

Observing thatx,, xt are both necessarily < /, it is obvious that all the
above values of K are negative.

It would not be difficult to show from the form of the integral (28), that this is

always the case, whence it follows that

M the quantity (K' + K-) is always negatnre," (25).

and therefore in general Eq. 22 shows that in ease of rigid Supports,

" Of the Re-action-Couples at any three successive Supports at least one I /0~v
isnegative,,l ..?. / (26'"

0. Uniform Load: Clapryron's Theorem.— This is in practice
the most important case of the general Theorem, and is in fact the only
one usually given in Text-books. Taking the values of the integrals
(K', K") from the Table Art. 8, and writing, u/, uf = load-intensities
per length-unit in spans l'y 2*, the general Result (22) becomes for this
particular Case (with rigid Supports),

M,Z' + 2 M,(Z' + I*) + Mtl" = - £ * J* - } «ri*» ^.(27).

This particular form of the general Theorem of Three Moments is
known as " Clapeyron's Theorem "•

10. Theorem of Three Momenta applicable only to Supported Uniform
Beams. — The formation of the final Result (21) by eliminating ra from
the two Equations (19a, b) involves of course thatr, should be the same
in both Equations, s. e.} that the Elastic Curves of the two adjacent spans
V, V should have a common tangent at the common Support. This involves
the physical condition, that the two Spans should be in no way fixed or con-
strained, at their common Support, (except of course by the mutual con-
straint of their continuity), •*. &, that the Beam be simply supported at the
Common Support*

The formation of the system of (n — 1) equations above-mentioned,
is therefore legitimate only when the Beam is simply supported at all the
Supports over which it is continuous : there is of course no restriction
hereby as to the mode of Support at the ends.

The integration, moreover, with I taken as constant clearly restricts the
Theorem to Beams in which I is constant throughout the Beam, the only
important practical instance of which is that of a Uniform Beam.

1L Shear-Re-actions, — When the Re-action-Couples have been
found, the Shear-Re-actions are easily found as follows : —

Let Av A,, A„ AB + 1 be the (n + 1) Supports numbered from right.

Rt, Rf, Rt R» + , ,, (n + 1) Total Re-actions, „

Mj, M,, M, MB +, „ (n + 1) Moments of Re-action Couples.

*u ',i h ** » n SP"* » »

CONTIGUOUS UNIFORM BIAMS. 115

R'„ R', .... be the Shear- Re-actions at right and left of p* Span (lv).

Fp, P*,.... be the Shearing-Forces at „ „ „

R'h iT, .... be the Re-actions at right and left of/?* Span (/P), if discontinuous*

Fig. 8.

*♦■,

, -*fim-i|

I fa. I

R*-i

t-p-t

|Fp

7hi \ w kp

Fp-i

Then, by Eq. (5), M, + 1 = M, + (B'P - #,) ^, (28).

M, = M, + 1 + (R% - .R*,) J, (29).

whence B', = ^p + Me±JJZ*?b (80).

R% = *% + M>"M>*i (31).

Thus the two Shear- Re-actions R%, R"p at the ends of any span Ap Ap 4. ,
may be at once found when the Moments (Mp, Mp.^) of the Re-action-
Conples at its ends are known. Moreover,

R'p + R% = ffp + JR% zs Sjp w = Total load on the Span,...(32),
from which equation either is still more easily found when the other
is known.

12. Total Re-actions.— By what precedes it will he understood
that any particular Support Ap yields the partial Shear- Re-actions R% _ ,
to the Span on its right (of which it is the left Support), and R'p to the
Bpan on its left (of which it is the right Support). Thus —

Total Re-action at /** Support Rp= R%_t + R'p (88).

= -FV,+ F'P (34).

Substituting from Eq. (28a, 5), remembering to change/) into (/>— 1)
in the substitution for R% _ x

R, = 2?Vi + ff'p + Mp-.!"Mp + Mp + !~MP (35).

*p— 1 *p

Case of end Supports ( A„ An 4. t). — By above notation, it is clear that

M.-M.+,

B, = R*. = F, = S\ + ^=» (86).

B, + I = B». = - F». = fl*. + *■ ~fc— »', (37).

▼01. V.— BEOOKD 8BBIE8. &

116 CONTINUOUS UNIFORM BEAM8.

It is clear also, that if Wp =3 Total Load on pth span,

Sum of Total Re-actions, z= Sum of Total Loads, 1

When n of the Total He-actions have been determined, this equation
gives usually the easiest way of determining the remaining one.

13. Case of Continuous Beam simply supported at the two ends, — This
is the most ordinary case in practice : the Beam simply resting on the End
Abutments without being there fixed.

The End Supports are, therefore, unable to supply any Re-action-Conples,
so that the Moments at the two extreme ends (A„ AB 4. 1) are necessarily
zero,

i.e., M, =a 0; Ma + 1 = 0 (39),

and those at the (n— 1) intermediate Supports are, therefore, all complete-
ly determinable by the system of (n — 1) Equations of the " Three
Moments ".

14. Curvature, — The fundamental equation of Curvature

applicable to all Beams shows that : —

1°. **In Continuous Beams the Curvature (1 -7- p) is of the same sign as*)
the Bending Moment (M;, and is therefore, j

2°. * Concave upwards (like a Supported Beam) when M is positive ; Iyiia

8°. u Concave downwards (like a Cantilever) when M is negative ;

4°. " Vanishes when M is zero, so that the Curvature changes sign, passing
through a point of inflexion when M is zero ", -

These Results justify the general statements of Art. 1.

15. Elastic Curve.— It may be shown by a process, similar to that of Art.
6, that — using the notation of that article — if A,, A_>, A, be any three successive
Supports, the equation of the Elastic Curve is, with origin at Ag, —

In Span Aj A; ;

EI { f. (t> - vj) - 0 (*! - v2) \ = Mi + Mj I

+ t «■ + '/:/r * »• 1

In Span A, A,;

{r(t> — »a) — *(»,— O j = — g — .Ma + g M2 +

CONTINUOUS UNIFORM BEAMS. 117

The levels of the Supports vu vh o, are supposed to be given : in most applications
in practice, it is usual to assume them zero.

The values of the integral are given in Table below ; those of K', K* were given in
Art 8 : thus when M,, M„ M, have been calculated, the Elastic Curve can be plot-
ted by calculating its ordinate* (©).

[These ordinates are always so very small, that it is necessary to plot them on a
larger scale than that used for abscissa].

16. Deflexion. — The maximum ordinate of the Elastic Carve in each Span —
commonly called the Deflexion — is the only ordinate of any practical interest Its
numerical calculation is always one of considerable labor. The process consists of
two parts —

L To find the abscissa (*) of the Sections of max. Deflexion,
ii. To calculate the corresponding ordinate (£), which is the max. Deflexion re-
quired.
Step L The sections of maximum Deflexion are defined by the condition

x - ° • — - <**>-

Expressing which in Eq. (42a, ft) the absciss® (a?) required are given by
InSpanA1A„(4-^)Mi + (^-4-.^)M2 + §K' ^ ^

.+ t£* Mdxzz - Elfo - »,)

InSpanAfAt,(^-£l)M, + (rr-^-f)Bli + ^K-
+ rj Mdx = - EI (», - o

The levels (vu »,, vt) of the Supports are supposed given, (usually assumed zero) ;
the values of the integral^/^ Mdx are given in Table below, and those of K', K" in

Art 8, for the most useful cases of practice. Substituting these values into (44a, o)9
there result algebraic equations for finding the required abscissa (0) in either Span.

On examining the Table of values of J* Mdx, it will be seen that, for continu-
ous Loads (the most useful in practice), this equation will usually be a cubic in *, and
therefore somewhat troublesome to solve.

The best practical way of solving it is usually to reduce all the co-efficients to the
simplest numerical form possible, and then solve it by " trial ".

When one of the roots is recognizable a priori, the cubic is immediately reducible
to a quadratic, and this happens in two cases : —

(1), when the Elastic Curve is horizontal at any Support, in which case * = 0 is
one root of the cubics for the two Spans meeting at that Support, and
therefore divides out, thus reducing the equations to quadratics.
[This Case always occurs in the two middle Spans of a Symmetric symmetri
cally loaded Beam of an even number of Spans, e. g.t see Ex. 3].

118

CONTIHUOUS UNIFORM BEAMS.

M
W
►J

W
P

»
H

•J

O
W
H

•J
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s i

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I
Ti

H
CO

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iTU

04
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fi

V A

•i »

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04
I

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a I i

+
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04 I

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II

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flu r?

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<

OOKTINU0U8 UNIFORM BEAMS. 119

(2), when the Elastic Carve is horizontal at middle of any Span, in which case

x = 1 2 is a root* and is in fact the abscissa required.
[This case always occurs in the centre Span of a Symmetric, symmetrically
loaded Beam of an odd number of spanB, e. g.f see Exs. 4, 8, 10].
It is worthy of remark, that the maximum Deflexion seldom occurs at the section of
positive maximum Bending Moment.

Step ii. To calculate 8 (the maximum value of 0). This is fonnd by substituting
the value of the abscissa (0) of the section of maximum deflexion into Eq. (42a, b).
The labor of calculation is much reduced by a preliminary redaction of Eq. (42a, I);
thus by help of the relation (44a, &,) the Eq. (42a, ft,) may be reduced to

Span A, A.,, EI (J - v£ = ^ (It, - Mi) - y M, -f * 9Mdx (45a).

Span A, A„ EI (* - «£ as ~ (M2 - M,) - y M> -J* wMdx (466).

The substitution of the values of x found in Step i, into these Results will give the
required maximum Deflexion (#) far more rapidly than the direct substitution into
(42a, b). The depression v is usually assumed zero.

N.B. — The resulting Deflexion ($) will usually be negative ; this indicates down-
ward Deflexion.

[The Table of values of the integrals f Md*% f wMdx, j J Mdx given

above will enable any one to calculate the Deflexion without any knowledge of In-
tegral Calculus whatever for all the most useful cases of practice. As already re-
marked the actual calculation will always he laborious, as the Equation which gives
the abscissa (*) of 8 is usually a cubic.

The maximum Deflexion may, however, also be found roughly— (usually with suffi-
cient accuracy) — by plotting a few ordinates of the Elastic Curve (on an exaggerated
scale) calculated by Eq. (42a, b). The probable value of the maximum ordinate
may then be picked out by inspection of the figure. This is also rather laborious].

[Caution. — From a hasty generalization of the fact, that a Continuous Beam is com-
monly in condition of a succession of Supported Beams and Cantilevers, Beginners
often make the mistake of attempting to calculate the Deflexion in any Span by cal-
culating the partial Deflexions of those portions of each Span which are in condition
of Supported Beams and Cantilevers. This is a procedure, however, which requires
great caution, and to effect it properly would in fact be mors troublesome than the
process developed in the Text."]

Hardly any of the Results (0. 0., values of m', m", n\ n", used in Rankine's Manuals
of Applied Mechanics and Civil Engineering), for the ordinary cases of Cantilevers
and Supported Beams, are really applicable to the cases of Cantilevers and Supported
Beams as occurring in Continuous Beams.

Those Results are, in fact, subject to the limitations,

(1). Cantilever, The ' Neutral Surface ' must be horizontal (or J_r to the
Loads) at the fixed End.

(2). Supported Beam, The 'Neutral Surface' must be at same level, and of
same slope at the two Supports.

Now these two Conditions obtain only in particular cases in certain Spans of Con-
tinuous Beams, bo that these simpler Results are seldom applicable to the latter.

120

CONTINUOUS UNIFORM BEAMB.

The error that may be made by an incautious use of Results proper only to Sap-
ported Beams and Cantilevers, is often considerable, as may be seen below : —

Continuous Uniform Beams, Eqnal Spans, Uniform Load.

Distance of max. Deflexion from End Support

True distance

8npposed approximate distance

Beam of two Spans,
Beam of three Spans, . . I
(Side Spans), . . . . J

•375/
•4/

It is obvious that these discrepancies would amount to many feet in large Spans.
17. Symmetric Beam, under Symmetric Load. — The solution in this
Case, which is a common one in practice, is much facilitated by observ-
ing that in consequence of the complete symmetry both of the Spans and
Load about the middle point (0), all quantities such as R, F, M,t>, 2 are
equal (in magnitude) by pairs at equal distances from the middle.

This consideration reduces the number of independent quantities to be
found by one-half. Thus —

R, = Rn+1 R, = Ra, R, = R^, &c, (46).

M, = Mn+1 Ma=MB, M^M^, &c, (47).

P = — P , M = M (48).

Case of middle Span. — In a Symmetric Beam under Symmetric Load
with an odd number of Spans, let m be the number of the middle Span
(counting from either end), Wn the Total Load on it, then by the condi-
tion of symmetry which gives Mm+1 = Mm, and Eq. 28a, b,

R'm = iv m === i Wn = i? m = R tn, (^9).

Thus the Shear- Re- actions of this Span are the same as if this Span were
discontinuous at its ends ; hence —

" The Shearing Force throughout centre Span of a Symmetric, symmetri-^
cally loaded Continuous Beam is precisely the same in all respects as if this > .-(49).
Span were discontinuous ", J

18. Transverse Strength. — The expressions for the Longitudinal
Stresses (C, T), Moment of Resistance (M), and Shearing Resistance (dF),
which are investigated in ordinary Treatises on Applied Mechanics for the
case of " Supported Beams " are usually established in a perfectly general
manner, and are therefore applicable to case of Continuous Beams.

It must be remembered that the character of longitudinal Stress depends
on the sign of the Bending Moment (M), and that there are therefore

CONTINUOUS UNIFORM DEAM8. 121

(1). Contraction, and Compressive Stress along all parts on the concave side

of the neutral Surface,
(2). Extension, and Tensile Stress along all parts on the convex side of the

neutral Surface.
The expressions for C, T, £3, #", with the values of M, F of this Paper,
enable all questions on Transverse Strength of Continuous Uniform

Beams to be solved.

[The Results of this Paper are, however, in strictness limited to Uniform Beams,
see Art 10, so that the sections of (absolute) maximum Bending Moment, and of
(absolute) maximum Shear must be held in strictness to fix the scantling of the whole
Beam].

Examples of Continuous Uniform Beams under Uniform Steady Load.

19. Here follow the reduced Results for the simple Cases of Two
Spans, Three Spans, &c, under Uniform Steady Load — the only case
usually worked out.

The notation is the same as explained in Arts. 2, 11, in addition to

which

O is the middle point of any Span, and origin of the abscissa? (£),

wlf W.& *?„ &c, the uniform load-intensities per length-unit, 1

I„ I„ I,, &c, the points of inflexion of the ' neutral surface ', / *n *°6

lit], in.}, m„ &&, the points of (positive) max. Bending Moment, > spans

E], E*, Ej, &c, the points of max. deflexion, I i*' ^

M0,i M0,.i M0,, &&, the (positive) maximum Bending Moments, J

x\ of the absciss® of any section P in any span ; x\ of being measured from the
right and left Supports respectively of that Span.

Ex. 1. Trco spam each uniformly loaded.

<r„ fa,, the uniform load-intensities per length-unit of Spans llt J}.

R„ R>, R, the Total Re-actions at A], A3 A,.

R'„ R', ; R'j, R% the Shear- Re-actions of ll9 1* respectively.

Jffl9 R?x ; R& R'i the Re-actions of spans /„ .,, if discontinuous.

M , the Moment of Re-action-Couple at A>

M0|i M0,, the (positive) max. Bending Moments in span /lt lr

Observing that since the Beam is simply supported at Alf A„ the Re-action-
Couples at A„ A, both vanish (Art 13), the value of Ma is given at once by Clapey-
ron's Theorem, (Art. 9),

2 M2 Oi + « = - i (w, V + «* V) ~ (5°)-

Observing also that —

B\ = !«!/, = kVu and R'2 = | W72 J, = JTf

The values of the Shear-Re-actions are given at once by Eq. (30, 81).

R', = J », I, + Mi, »•, „ j „, h _ £

* %L >...(61).

R', = | wtk - ^, R'2 m i m, k + S,

The Tallies of the Total Re-actions are given at once by Eq. (86, 87).

B| as R'i ; Rj ss i»i «i + »j t| — (Ri + B»)> Bj =s B"j ....... (52).

122 CONTINUOUS UNIFORM BRAMS.

The Shearing Force at eny point P,

Span /„ F = li\ - wx* zi — (R'j - wxx*) 1

Span /„ F = R', - *>*• = - (R#, - «>,*•) / (58)'

Also at Ab F', = R', ; at A,, F*, = - R'„ F'2 = R'2 ; at A„ F% = - Wh ... (54).

The Bending Moment at any point P,

Span

(55).

Span

There are usually two inflexions, one in each span, whose abscissa are.

Span *,. = — ' = 'i + ^|

.. (56).

, - SR^ , , 2M.f

Span I,, *" = J-=*H r I

*' to, w I, ]

The Bending moment has usually three maxima, viz., two positive maxima— one in
each span, — and one negative maximum,

R1* R'

Span/,, M0, ,= i —-1 ; where *< = — >, and F = 0

At A._, M = M2 a negative maximum / (57).

R"* R*

Span Jj, M0,o = i — *, where *' = —^and F = 0

Thus the sections of no Shear and of positive maximum Bending Moment, bisect
the segments Ax ll9 A, I, between the End Supports and Inflexions.

JBr. 2. Two equal spans each uniformly loaded.— This is only a special case of
preceding, but sufficiently important to be worth recording. The Results which are
easily derived from the last (by writing lx = l2 ss / = 2c in the last), are

Moment of Re-action- Couple, M* = -tV(»i + *>i)P = - i(»j + fO *... (58).

SWifc^rfiow.R', = 2-2Lri25L i, R«, = 9 W\t Wl l

P. __ »i 4- 9 w.> , p, _ 7 W.J - w, y ' *59)'

B*-? 16 '' R* 16 l

Total Re-actions R, = lm\~w>i . r - 1 (*,+«,) wi ; R, = 7fP'.7W7, (60).

jo lo

The general values of F, M, and of the maximum Bending Moments cannot be
more simply expressed than in last Example, q, v.
There.are usually two inflexions Ilf I2, one in each span, given by

* * - 0 + 57) I- A-- *• -(l + y * ~ (61)-

It is worthy of note that if w.2 diminishes whilst », remains constant, Ij approaches
A«, Ij recedes from A, and R% decreases, until

when w.j — | »„ R'j = 0, A> I, = T /, A, I, = /,
so that the left span A2 I2 ceases to press on the Support A„ and is everywhere
convex upward.

If ir. continue to decrease < f wlt R^ becomes negative showing that Tension if
required at A„ until finally

PLATE XIX.

i CONTINUOUS UNIFORM BEAM OF TWO EQUAL SPANS.

'Diagrams of Shearing Force and Bevdisg Momxnt for varying Uniform Load.

a,u

Load.

*pus dUcontinocmi, uniformly lotted,

Explanation.

Span A, A.j

A|Aj unloaded. A, A, uniformly loaded,
AtA^ A, A, both uniformly loaded, . .
A, A, aaiformly loaded, A, A, unloaded,

• ■

SBEARIira Fobcc
F.

Span A> Aa

F0i»Q Fp

F,a», F,
F,*», F,

Ftw# F#

Bending Moment
M.

8pao Ai A>

Span A) A,

F. lAiMpA,

*>,Fj

Fi*i *V
F,F3

A.M

A,M, lif ,
A)!!, IM,

j..

Aj Mp Ag

Jk-mIHiAj
JBiI3hL|A«

k,A,

Mo?iaf

TtewllMtM

k"ll

potitire,
load,

negative,
Ik. OfMtMt T<l«*> F. ■ «i <Mfe imia..

GaBATKR VltUW

F M

F,F,

A.F,

Ex.2.
Kx. 8.
lx.S.

CONTINUOUS UNIFORM BEAMS. 128

when n>2 =s 0, Aa I2 = \l> A2 1, = oc» B% = — jr »i *•

[7%ztoXIX. shows the Diagrams of Shearing Force and Bending Moment for this
Beam for the particular Cases ; 1°, w1 = 0, v3 finite ; 2°, wx = Wj ; 3°, Wj finite, wt ss 0 :
as well as the corresponding Curves (dotted lines) for discontinuous Spans for sake
of comparison : for references, see Plate XIX].

To find the abscissae of the sections of maximum Deflexion, substitute Mt = 0,

M2 = — -A (»i + vj) P9 M, = 0, and the values of K*, K', t* Mdxhom the Tables

of Arts. 8 and 16 into Eq. (44a, b). It will be found on reducing that the abscissa
(*) is given by solution of the cubics,

8r^£_A(9 + J)£ + ,(l + ^)£+J(l_^) = 0, (62*).

The solution cannot be conveniently expressed unless the ratio wt : to3 is given in
a numerical form, (see next example). [Observe that only the positive value of »
which is < / will suit this Problem].'

To find the maximum Deflexion (£), Results (45a, b) give, on substituting for M„

Mj, M„ J sMdm (the last from the Table), after reduction.

*««"-a?.{u£-i(i+5)5+»(i+a)£} *»*

■"»4.ii-5tf{M^-i(t + a)? + «(l+a)^} (686),

in which the values of x -f- / derived from Eq. (62a, b) are to be substituted.
These will generally be negative quantities, indicating downward Deflexion.

Ex. 8. Uniformly loaded, Uniform Beam of two equal spans. This case is
more common in practice than the last, of which it is a special case. The Besults
(easily derivable from the last Example) are —

Moment of Re-action-Couple M.3 = — } wP = — \ we* (64).

Shear Re-actions R'j = f wo as R'3 ; R", = J we = R'3 « (65).

Total Re-actions R, = I we = R, ; R2 = $ 100 (66).

Shearing Force F^ = f w as — F*2 ; — F*, = f aw «= F*2 (67).

Span J„ (A, P =s *>), F = | we - w*'l

8PAN *„ (A, P = aV),F = f wo - nw'i ™ <W''

Bending Moment : —

8pan /lf (A2 P sb »'),M =s f tew*' - 2y

„**> (69).

Span ^ (A, P = *f)t M = | we* - ^- '

There are two inflexions, (I]f l>) ; A, I, s= £ c ss A2 Ij (70),

The Bending Moment is a negative maximum, M2 = — i we* at As, 1

and a positive maximum, M« = /g wo* at middles of A1 Ij, A, Ij / " ^ '*

[Plate XIX. shows the Diagrams of Shearing Force (Fx m1 Flf Fj Mt F|) and
Bending Moment (A, M^i Mlf M, *a IMj A,) for this case].

VOL. V.— 8BOOND SBBIB8. 8

124 CONTINUOUS UNIFORM BBAMB.

To find abscissa of sections of maximum Deflexion, writing n\ = w2 in (62a, 6),
both Results become after redaction

7i--g--j + l=0, whence j ss — =j£ — = -57847 (72).

Both Besults (63a, 2) reduce to

[The negative sign indicates downward Deflexion].

JEr. 4. XAfw uniformly loaded Symmetric Span* ; Symmetric Load,

/„ If, l» the Spans ; /i=/,

W|( w^ w„ the load-intensities per length-unit ; ip, = w,

Hence since for simply Supported Ends, Mt = M4 = 0, CUpeyron's Theorem gives,

(Art 9),

2 M, (/, + J,) + M, /, = - * (»! V + «, V) (74),

and by the symmetry Ma s M,

••• m« - -»^'+*y - m» • (76>

By(3O,81),B^==ii0W1 + -^=R%5^ = iw,«i-^,= R*»l (T6)b

By (48), R'2 = \ wtk^BrJ. .! J

By (86, 87), R, = B', ; B, == \ wx h + \ wt l> - ^ e> B, ; K4 = B%. (77>

flufr Spam; w = A, P or A4 P, ± P = B, — n^ ».....l ^8^

Centre Span; ±$ = OP, x P = »* * J

Side Spam; a? = A1PorA4P, M=R|C — J*?!*9 1

Cenrr« ^mi / ± £ = OP, M = M, + 4 ** (** - * •) f "9>

2
Side Spam ; Inflexion at I, At I = — **'i = A4 1

(*>).

Centre £jwit ; Inflexions at I, I,

01 -±y* +£* I

Side Spam ; Positive Maximum of M is !&% ss ~- Bj1

at middles of segments Ai I, A4 1 I

Centre Span; Negative maxima of M, via., M2 or M, at Ao, A, ; j * (pi)*

also at O, Mo = M2 -M wef I

[Mo is a max. if positive, minimnm if negative]. J

Ex. 6. Three uniformly loaded Symmetric Spam. ft as /,).

By Clapeyron's Theorem, observing that M, = 0 = M4.

2 Ms(/I + J,) 4-M.^s: - * (an /,» + ♦*,*»»

2 M, (^ + ^) + M, /, = - J (», l? + w2 lf)f ^

whence M = 2«i(t + UV^i(2l1+W^,^ )
whence M, 4(2 ^ +8 «8)(2/1 + /») I

M _ _ 2 »,( /t + *,) y + n>t (2/, + ij ) tf - my 4 f "(88>-

'" 4(2/1 + 8/,)(2/i+«i) )

[It is not worth while developing the other Results of this Case, as the formulas
become complex. The Results (88), however, are required for investigation of effect
of Moving Load on a Three Span Beam].

JZLATE XX.

N«-

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M*- ic O

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a

I
: J

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9
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a i

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33 1£

a
a

CONTINUOUS UNIFORM BEAMS. 125

[Plato XX. exhibits the 8hearing Force and Bending Moment Diagrams for a
Continuous Beam of Three Equal Spans, each under uniform Load, for the most im-
portant Tallies of the ratios of *, : wt ; n>„ viz.,

(1), *?i = W, ss w9 ; (4), w, s 0 as «„

(2), Wj a 0, w2 «= », J (5), »i a W|) «» «■ 0,

(8), KTj ss »„ », = 0,

as well as the corresponding Diagrams for discontinuous Spans for comparison with
the rest].

Ess. 6. Uniformly loaded Beam of n £?««! Spans.— This case is approximated
to in the Rafters of some Roof Trusses, which are often of uniform section through-
out, and supported on several equidistant Supporte (Ridge, Strut-heads, and Wall-
plate), and also tolerably uniformly loaded.

The Total Re-actions (R„ R, , cVc.) are equal and opposite to the Pressures of the Raf-
ter on its Supports, and, are therefore, the " Equivalent Loads at the Joints " required
as the M first Step "* in finding the Dijubot 8tbbs8ES in the Bars of the Truss.

The greatest of the Moments of Re-actionrConples (M)9 M* &c.) is the maximum
Bending Moment (Mn) required in calculating the stress due to flexure,f in the Rafter*

[In the investigation of Dtjibot Stbbsbbb in Roof •Trusses $ and again in the
special investigation of the additional (longitudinal) Stresses due to Transverse Strain
in RAFTBBRf ifc i* often preferred to use the Hypothesis of Free Joints J in finding
the " Equivalent Loads at the Joints", and * Maximum Bending Moment", as the
values so found are at once obtained in an elementary manner, and it is doubtful whe-
ther the new values obtained by the present method are really better approximations.

It must be remembered that the numerical valnes here given depend essentially on
the rigidity of the Supports (Art 7). Now in a Framed Truss, this rigidity can-
not exist The Truss will deflect as a whole, and along with it the Rafter, so that
the Rafter- Joints will certainly settle, and by amounts which are small, but probably
of same order as the Deflexions of the Rafter-segments, and therefore not negligible
from the Equation of the Elastic Curve. The proper coarse would undoubtedly be,
to make some allowance for these settlements (the vlt v„ t?„ &c, of Eq. 21), but it
would greatly complicate the investigation.

Meanwhile it is a matter of opinion which set of values are the more approximate].

Let w = load-intensity per length-unit of each span (J),

SB? = 3K' = -Jw/,= - 2wo* for every span (Table, Art 8).

Observing that for a Beam simply supported at the ends M4 as Mn + 1 = 0, Clapey-
ron's Theorem gives a series of (n — 1) equations of the form, (after dividing by
/ = 2<j)

4 M2 + M, = - 3*x* « MM + 4 M« )

Ma + 4 Ms + M4 ss - 2nw* s= M«_> + 4 M^ + M0 ( (U.

M, + 4M4 + M, = - 2w*» = M,u« + 4 M,^ + Ma-i f * *

-f- + sa — 2i0c* ss + 4. J

Between which (n — 1) equations, the • — 1 quantities (M) are easily found when

• See the Author's " Manual of Applied Mechanics ", Art. 115.

t See the Author's Paper " On Rafters and Purlins ", No. 0XX1 of Professional Papers on India*
Engineering, [Second Series],
|S«" Manual of Applied Mechanics ", Art. 118, et eeq.

126 CONTINUOUS UNIFORM BBAMS.

not very numerous. The Load and Beam being symmetric about the middle, (Art
17).

Mj = M„, M, = Mb+j, M4 = Mb_b, &c, &c, (85).

so that only half of them require independent calculation.

The Shear-Re-actiona, and Total Re-actions are now easily calculable by Results
(80, 81) and (86, 87).

The Shearing Force in p°» 8pan is

F = R'p - ww' = - (R% - »*•), (80).

The Bending Moment in^* Span is

M s Mp + R'p •' - | w** = Mp+1 + B'p <- \ w*f>, (87>

In the End Spans this reduces to

M = RW-i ">**, M = R%+1a^ - | wx« (88).

The inflexions (given by M s 0) are generally two in p* span at the sections,

*' = 5 (B'p ± N/»V + 2*> Mp) ; • =1 (R'p ± VR%«+2»Mp+i)..<89).
For the End Spans these reduce to a single point at

First Span, A^ = | R\ ; LastSpan,AB+1In a | R'B+1 (90).

The positive maximum Bending Moment occurs at section (given by F = 0) where

uf m U'p or *• = I . RV m <91).

andisMo)P = Mp + iR'p' = Mp+1 +^*'p\ (92>

The negative maximum Bending Moments are (M2, M„ MB) over each Sup-
port except the End Supports.

The Results reduced from the above for the particular cases n = 2 8 4 5 6 are
shown below— (for notation, see beginning of Art. 19)

Ear. 7. Two equal Spans. Ms = — i wc?
R'I= 3wc= R%, R#lS=|nwj=R'2
R]B |we = B„ B, =s « fpc

M0 = ^ wc* , A, «t, = !<J = A, mj

IPC*

*, = - -0867 ^| = ** As E, = -67847 J = A2 E_„
J3r. 8. Three equal Spans. Mj^-J^sM,

R', = | too ss R%, R'j = | wc =: R'„ B', s w s R*,
Rl cs4»0 = R4, Rj =3 y wc ea R,

A8I, = JcaA.1,, Ol^i-i-

M°>i =sAf"?,= M«,» Mo,i « ^ wo» (at O)

*!«*! S3 J o = A4 w,,

* = - -1102 ^~S» Aj^.-o^Z-A,^

PLATE XXI

-U^

o
1-

r«i

CONTINUOUS UHIFOBM BEAMS. 127

JEfc.9. Four equal Spam. Mt— -3WC« — M4, M, — -»nwf
R'^^wc-R',. R'j-^^^RV.R'j-U **-R%, R%=|3fw = R't
R,=» i£wc — Rw R*~ y**«=R4, R.-y*
A^-so-A.I* A, l.-ii^t-A,!,

A,«h =» ^J c — As«4, A,«s «= || c a- A,m>.
£a>. la JSw equal Spon$. M,» -^wc* = Mw M, « - ^ wo* = M4.

Rj^^w-Re, R^^fwo-R,, R,— 37WC=BSR4
A^I^^c-A.^ Aa%-^£«-A4Il9 01, = + */ Jc

Ai»i -* U « — A« »iw A, ^ = H c =» A4 »4.

JEb. 11. Si* egiia/ Span* M^- £J. Ktt'=M„M,»— ^ nw*=»Mft>M4=— ^wc9
B'^^wn^RV B'l-JI^^R', R'j=3«4«c = R%
B'«-H «*-*'» R',~£J **=.R'4, R'4-£f «c = R'4
R^^ wc^R,, Rj-fllwc^R,, Ra «. £* 100 = R,, R4 — £| n*.
A, It — U c — A 6 1* &c , &a

A^^*^ c *=■ A7 m*, &c, &c.

[Pfote XXL shows the Diagrams of Shearing Force and Rending Moment for the
above Reams, of from two to five spans. The Figures are all drawn on same scales,
with same Spans and same load-intensity for purposes of comparison.]

20. Effect of Moving Load. — Under a Moving Load it is obvious
that both Shearing Force and Bending Moment change continuously at
every section during the passage of the Load passing through certain
Greatest Values at each section usually at different stages of the passage
of the Load : these will be styled* the Greatrst Shearing Force and
Gbbatsst Bending Moment, and denoted by F, M respectively.

Their complete investigation in a Continuous Beam is always tedious,
(and is usually omitted in English works). One or two simple useful
Cases only will be briefly investigated here.

which win be used to denote the MuTimnm values of the Shearing Force and Bending Moment of
the whole Beam.

128 CONTINUOUS UNIFORM BEAMS.

There are usually two inflexions in the Elastic Curve in each Span of a
Continuous Beam which define the regions of ± Curvature and of db
Bending Moment. Under Steady Load these occupy a definite position,
but under Moving Load these points shift continuously ; throughout the
region of displacement of a particular inflexion, the Bending Moment is
liable to change of sign, and is therefore susceptible of two Greatest Values
(one + » one — ) at each section in that region.

[The Investigations following apply solely to the Moving Load : in applying the
Results to real Girders the portions of F, M due to the Permanent Load mast of coarse
be combined with these to give the Resultant Shearing Force and Bending Moment.

It follows of course that any small values of F, M due to Moving Load which are
of opposite sign to those due to the Permanent Load are of no importance.]

Ex. 12. Two Span Beam : under uniform moving Load. The process of finding
P, M may be divided into five Steps.

Step i. To trace the variation of K\ K*. \

Step ii. To trace the variation of Mg. I N.B.— Tor case of

Step iii. To trace the variation of R'j, R'j ; R'.:, R'j. > equal Spans, make It

Step iv. To trace the variation of F. I = h throughout

Step t. To trace the variation of M. J

Step i. Variation of K', K'. (Observe that these are always negative, and that
I, K stand for J„ K' or l* K" as the case may be).

1* Segment Aj P = *j ^^, K = ^ (*,« -2/*) = - jj, j * - <P - *,V | C»3a).

2°. Segment BP «= *2 loaded, K = - ~j (/• - *,*)« = - ~ {*» -(i-jrj"}* C93*>

In both cases it is clear that — K increases (with *lt *2 respectively, u e.,) with the
extension of the Load, and is a maximum when xx as 2, or x^ s *, i. e,, when the
Span is fully loaded, i. «., when Ks=-^ vP.

STEPii. Variation of M>. By Results (22), (89),

2Mjft + J,) = 8 (K' + K'), .-. M2 = 8 (K* + K*) + (/, + /,) (94).

/. —Mi increases with the Load, and is a maximum when llt /j are both fully
loaded.

Step iiL Variation of R'„ R*„ R',, RV It is easily seen that that #„ «*, ; It'*
R't increase with the Load on lp l& respectively, and are always +.

By (80, 81)^ = «*i- X • *'• = R'2 - r : o£ wMch " ** te alwiy8 + ***
increases with the Load,

.% R'j, R't are alwayB + and increase with the Load, ... (96>

By (30, 81), R'j = 1^ + ^, R% as BTt + ^. As Mg is always - ,it is dear

1 2

that R'j, R*8 may be either ±. It will suffice to trace the variation of R'j.
By (80), B'j = /f,+ fr7T~rr) ; <"* H****** Civil Engineering, Art 161,

CONTINUOUS UNIFORM BEAMS. 129

Ex. VIL for J?,\ and Art 8 of this Paper for K', K"> The two cases of Load on
AjP or AaP require separate consideration.
Case (1> Segment A,P = wl loaded.

_ n*9x (2/, - *,) tMr,»(2i1»-g1«) 8K*

*~ 2/, " 8V (/, + /,) "*" 2*, ft + *2)

2^ * 8/,"ft+*,) ^ft + U *>""»

of which the two first terms (together) may be shown to be essentially -f and increas-
ing with «j («] < /|)9 and the last — :

Case (2). Segment A,P as a*2 loaded.

_ »V _ <we>' (2'i - *>)« . 8K*

">- 2/t 8tfft + « "f'2/1(/1 + /2)

_ wmf r _ (2/t - «,y 1 8K*

- "2]T I 4/, ft + « 5 + 2/2 ft + I,) CW6>

of which the first term is essentially + and increasing with *>, and the last is — •

Combining these Results, it follows that:—
(a). " K'i is a negative max. when lx is nnloaded and l> f ally loaded ", %
(ft). MR'] increases with + sign with extension of the Load on J)( > ......... (97).

and is a positive max. when I, is nnloaded and /, f ally loaded ", '
8imilar Results obtain mutatis mutandis in the case of R'g.

Step iv. Variation of F. It may now be shown* by elementary considerations
that F attains its greatest value (F) on the span lx when the longer segment of that
span is covered as follows : —

(1). Greatest positive value (near Support Aj) when the longer segment AfP
( s sf) is folly loaded, and L unloaded.

y - Kl - 2/, \ l 41, ft + « J C98>

(2). Greatest Negative value (near Support A>) when the longer segment A(P
( = O and also the other Bpan ft), are fully loaded.

~ \ W 21^ 8/,»ft + « ^Bfl + Oj

2/, t + 4 /, ft + y / 8ft + « <*>•

Similar Results obtain mutatis mutandis on the other span ft), remembering
especially to change the sign of P tern ±: to ^ according to the usual convention of
the sign of a Shearing Force.

[The graphic representation of J" is givenf in Plate XIX. by the (chain-dotted)
lines F, A, and F2 Ft for the span J,, and by F9 A> and F, Fx for the span y .

Step v. Variation of M. It may now be shown* by elementary considerations
that M attains its greatest value M at every section on the span ^ as follows : —
(1). Greatest Positive value, (near Support A2) when 2, is unloaded and ^ loaded,

* Similar to those of Art 819, of Ranldne's Applied Mechanic*.
t For esse of equal Spans ft = /£,

ISO CONTINUOUS UNIFORM BBAM8.

M =R',*'-W-^= 7 wcx* _ W^L. (100).

Mo,i = ^ R'i« = yfy wc», where *' = * c (101).

(2). Greatest Negative value, (near Support A,) when /» is loaded and lt unloaded.

M = R'i *' = - i wca?\.....! (102).

(3). Greatest Negative value, (near Support At) when both Spans are fully loaded.

M = j M, + M 1 (c - *y + • «**•, (

Mm = — J wc' at Support A9,

Similar Results obtain mutatis mutandis on the other span J*
[The graphic representation of M U given* in Plate XIX., by Ax M, I and Ax ^ Mi
for the span ll9 and by A, Ms I and A, e2 M2 for the Span fc]

JSr. 18. Three-Span Symmetric Beam under uniform moving Load, The in-
vestigation of this case will be very briefly given — (£, = ^ c= Q.
Step i. As in Ex. 12, K = — ^ tcJ9 at a maximum.
Step ii. From the values of Ms, M, in Ex. 5, it is easily seen that

" — M>, — M, are maxima when wt = 0, rcl = 0, respectively. * nni«Y

and the other spans fully loaded ",.. J ••" * *

" + M>, + M» are maxima when u>j = 0, w2 ss 0 ; to, = 0, 1 /ifliAi
tos ss 0 respectively, and the remaining side span fully loaded ", / ••'• *
Step iii. Fariarton ojf R'„ R'x &c

R'x = *', + *£ = J *,* + ^ , R% = •«,* + -J* (105).

From (83), it may now be shown that —

" R^, R% are maxima when w% = 0, and /], ^ are fully loaded", (106).

R'2 = * Wl/ - ?£, R', = JWj/-?Jj (107).

From (88), it may now be shown that —

« R*!, R', are maxima when w9 = 0, Wj = 0, respectively, i

and the remaining spans fully loaded ", •• « J ~ * '*

B', = Rt + ™±=*->, R% = srs +*k=2h (109).

From (83), it may now be shown that^-

R'„ R'j are maxima when wt = 0, w, = 0, respectively, and thel

remaining spans fully loaded", j

Step iv. Variation o/F. By considerations similar to those of Em* 12, it may
now be shown that F attains its Greatest Value (± P) in any Span when one or
other of the Segments tC, of extending up to the Section is fully loaded, (and the
other x9 or *', unloaded), and the remaining Spans so loaded as to give the Re-action
at the end of the unloaded segment its greatest value— (according to the Results in

Step iii).
[The above Statement is obviously a perfectly general Result applicable to all

Cases].
Step v. Variation of M. By considerations quite similar to those of Ex. 12,

• For case of equal Spans (^ = £),

CONTINUOUS UNIFORM BEAMS.

131

it may bow be shown that M attains its Greatest Value (M) at every section in each

8pm is follows: —

Load-distribution which pboducbs

Spivs

Qreatest + Bending Moment

Greateit — Bending Moment

Side Spans 1
(not near Piers). J

Cher and near Piers.

Centre Span I
(not near Piera). J

Side Spans loaded.
Centre Span empty.

None.

Centre Span loaded.
Side Spans empty.

| Centre Span and farther Side

V Span loaded.

\ Remaining Span empty.

i Two Spans meetingat Pier loaded.
I Remaining Span empty.

( Side Spans loaded.
| Centre Span empty.

Plate XX shows the Diagrams of Shearing Force and Bending Moment of a con-
tinuous Uniform Beam of three equal Spans, under the five different distributions of
Uniform Load which produce the Greatest Hh Bending Moment fcfc M) at
*** part or other of the Beam. This sufficiently illustrates the above principles,
ft ta not been thought necessary to exhibit the Greatest Shearing Force (F).

A numerical Example is here added to illustrate the principles and formula cf
this Paper.

&> 11 Pennair Bridge, (Madras Railway). This Bridge is borne on Continn-
008 Girders of I-section of two equal (64') Spans.
dotation. At, Ac the cross-sectional areas of tension and compression flanges.
A, the cross-sectional, area in shear ( of Web).
A the whole area of cross-section = At -f- A« -f A*
PhPctPt the max. tensile compressive, and shearing stress-intensities

in a cross-section.
yu yl9 the distances of the " neutral axis " of cross-section from its

convex and concave edges.
d' the effective depth of cross-section.

Jtor\ J, = 64' = *,,(? = 45'.

GwwecfMHa symmetrical, — Over Pier, At = 28 sq. in. = Ac, A, = 17 sq. in.

In Side-spans, At = 18 sq. in. = Ac, A. = 17 sq. in.
te*& Load, uf = 8*6 cwt. per ft. run ; Moving Load to* = 10 cwt per ft. run.
Find maximum maximornm and permanent maximum longitudinal and shearing

«ta*intenaities.
SohUioh. By the well known expression for " Moment of Resistance ", flU = — . I,

orTft.L

And in a symmetrical cross-section yt s - = y&

' TheDtta an taken from No. CCLX. of " Professional Papera on Indian Engineering ", [Ylrtt
fcrto.]

VOL. V.— SECOND SERIES. T

183 OOHTIHUOUB UHIPOBK BKAlfS.

/.J>torpe=j.™ s=g-. ™ by the « equation of moments'.

And* in an I-section, I s J« . (i^ + <A> + ^^ + 4A'A« )

Bnt in a symmetric crass-section, Afe ss Ae, and A as 2At + Ac

d" / x

Hence on reduction, I = rr-f Ai + 6At 1

AndpeOrPt=^(A6^6At) in general,

/. *« or p, = j-^———-. a -j-— ow Pier,

= 45(17 + 6x18) = ~937*" 'm »**«■•
And by what precedes it appears that—

"M* F*i,Fj are greatest, or become Ms. F» F* oyer the Pier when both Spaas
are loaded ", in which case wL a 13*5 cwt. per /L ram a **,.

/.Mj= -iWjc'a -| x 18-6 X 82* a - 6912 ft. cwt. a - 82944 incA *»«.

-F*! =Fa = R*i = 4 "i* =| X 18-5 x 82 = 540 cwt.

Alflo"M0jl, Fx are greatest, or become M^ Fi when ^ is loaded, and J, empty •*

in which case wx = 18*5a diet per ft. nm, a w2

,.,.r,.r,By,,!!y„^W->',.1Mti

11^ = M.,1 » ^- B'l* = rxHfg = 49OT,26>*-«»<. = 68887-1 inch ewi.

and occur at distances a — ss |££= 27* from outer Supports (Alt A,,).

Hence the maximum maximorum longitudinal stress intensities are
p, or p« = | J g£ £ a 71*4 cut p«r «g. in* oyer Pier,

pt or pt as 5£gf.'£ — 63 cwt per sq. in. in side spans 87' from Pier.

And the maximum maximorum shearing stress-intensities are
pt a ^j? a 81*8 cwt p*r *g. in. over Pier,

p, a 3^4 = 21*4 cwt. per sq. in. at Abutments.

The permanent maximum stress-intensities are due to the Steady Load alone in

which case wx a 8*5 cwt. per foot run a w3

M, = - * ttv?» = - * x 8-5 X 82« = 1792/*. cwt. a 21504 tftcA-c»t

-I",aFj = R'1 = Jw1c = Jx8'5x82 = 140 cwt.

- F% as F, B3 Bfj -a 1 1^0 bs | X 8*5 X 82a84cirt.

1 84*

M.,,^ Mfl|1 a 2— B'^ a -^ = 1008/1^1. = 12096™*^!.

A«fl the permanent maximum stress-intensities are—

21504 ,OK ,

.- -■ Tii55sslMaiit',ri*fa"
longitudinal,

<a.

{21504 fOK ,
12096 fo ,
*e OTPl = "987T = 8 y<r# *

• Bmnklne'i Civil Bngtwering, Art. 163, BS.XX.

CONTINUOUS UNIFORM BEAMS. 133

140

p% m jf sz 8*2 cwt. per sq. m.

84
j>. = -jy = 5 cwt per eq. in.

As this Girder was brought into position bg rotting from one end, it is advisable
also to find the maTimnm stress-intensities dne to this cause ; these occur when hall
the Girder 64' overhangs like a Cantilever loaded with its own weight only (w « 275
cwt. per ft run, excluding superstructure).

HereM.=: - 1 u* = - « X 2-75 x 64*s - 6632/*. art. s -67584 mmA-m*.
— F. sb R* = 2 75 X 64 s 176 cwt.

And the maximum stress-intensities (of rolling)

Longitudinal, p%, or pc = s 58 cwf . per $q. in.

176
Shearing, p% c= — cs 10*4 cwt p«r *g. in.

All these maximum stress-intensities are well within the working stress-intensities
of good wrought-iron.

The m^""ww Deflexion will occur under that arrangement of the Moving Load
which produces positive maximum maximorum Bending Moment, in which case
fpj = 18*5 cwt per fool run, w2 = 8*5 cwt per foot run.

The abscissa of the section of max. Deflexion is given by the positive root, (< J)
of Eq. 620, which gives—

£-*<9 + wV)£ + tO+tV>7 + *0 -*)=*&

The value £ = a5878 will be found to satisfy this nearly. The maximum Deflexion

is then given by Result (68a),

> "i* (,«*• 500*» 84 **\
J=l'|12? 27*? +9 "?J

lsjs^iw x (g2 x 12)l x (_ 2.7n) r redndng all nnita to j^^ and m^

•= ,a*J \ and taking E as 24000000 lbs. per

24000000 X ^ X (17 + 6 X 18) J ^ «WWWlM.p«

= — -708', and occurs at '588 x 64' as 84 '-4 from the Pier.
Again, when the Moving Load covers both Spans, the abscissa of the section of
maximnm Deflexion is by Result (72)

x = -578 1 = 26'-8 from the Pier,
nad the Deflexion is by (78),

j , *gg?^ , "°867 x li:^T * (32 x 12y „ ir

m 24000000 X SSi'.X (17 + 6 X 18)

These Deflexions are both so small that it is not worth while calculating that due
to the steady Load alone.

{In the published official calculations about this Bridge, (No. OCIX of "Profes-

134 CONTINUOUS UNIFORM BEAMS.

sional Papers on Indian Engineering, [First Series]), these Deflexions have been
altogether miscalculated. They have been apparently assumed to be exactly the
same as in an ordinary " Supported Beam/' t. e., one fulfilling the conditions ex-
plained at end of Article 16,) of length equal to the portion between the inflexion
and abutment. This procedure causes an error of abont 8' in the position of the
maximum Deflexion, and considerably under-estimates its magnitude.]

21. Fixed Beams, Fixed and Supported Beams,— -The Fixa-
tion of one or both Ends of a " Supported Beam " may be defined to
consist in preventing to a greater or less extent the alteration of slope at
one or both ends of the * neutral surface', which would take place if simply
supported at the ends.

With this definition, together with the explanations in Art. 2, it must
be clear that this effect is produced by the application of a certain Force
together with a certain Couple at those ends which are said to be * fixed %
and that, therefore, the Cases of a (more or less perfectly) Fixed Beam
and of a Fixed and Supported Beam fall under the principles of this
Paper, (see Result 3 of Art. 2).

Thus a Fixed Beam in general is precisely in the condition of the cen-
tre Span of a Three- Span Continuous Beam, and a Fixed and Supported
Beam in general is precisely in the condition of -either Span of a Two-Span
Continuous Beam.

Ex. 15. A Fixed Uniform Beam under uniform load is precisely in the condition
of the centre Span of the uniformly loaded Symmetric Three-Span Uniform Beam
of Ex. 4 of this Paper.

It will suffice to make /, = 0, /, = 0, in the Results of that Example to make it ap-
plicable to this Case.

Ex. 16. A Fixed and Supported Uniform Beam under uniform load is precisely in
the condition of either Span of the uniformly loaded Two-Span Uniform Beam (with
equal Spans) of Ex. 3 of this Paper.

It will suffice to make either d = 0, or /, = 0, in the Results of that Example to
make it applicable to this Case.

22. Fixed Continuous Beams. — In all the applications made up
to this point it has been supposed that the Beams were simply supported
(Art. 13) at the extreme ends, which at once assigned the values of the
Moments (Mi ■= 0, Mn + x = 0) of the Re-action- Couples at the ends.

The Case of a Beam (more or less perfectly) fixed at the Ends may also
be solved bj the principles of this Paper, if definite values be assigned
to these Moments (Ml9 Mb^ ) of the Re-action* Couples which cause the
fixation. The solution would, of course, require to be taken by solving the
system of (n — 1) Equations of Three Moments de novo, as the actual

CONTINUOUS UNIFORM BEAMS. 135

values of the Re-action-Moments, and Shear- Re-actions are usually altered
throughout by this alteration of Mp Mn + i.

But if the Fixation of the Ends be simply described as ' perfect ', the
values of M„ M„ + , would require special determination by the consider-
ation that they must be such as to render the slope at the Ends zero. To do
this, however, the integration of the Elastic Curve should be performed
anew, as the condition must be introduced during the integration. The
Case is, however, hardly of sufficient importance to require special develop-
ment here.

22a. Fixation of intermediate Supports. — It was explained (Art. 10)
that the Theorem of Three Moments is applicable only to pairs of Spans
which are simply supported at the common Support. It is in fact applicable
to any such pair of Spans.

The Case of a Beam (more or less perfectly) fixed at any of its Sup-
ports may be treated by the principles of this Paper, if definite values be
assigned to the Moments of the Re-action- Couples which cause the fixa-
tion at those Supports: the Theorem of Three Moments may then be
applied to determine the remaining Re-action- Couples.

Again if the fixation at any Support be ' perfect' the value of the
Moment of the Re- action- Couple at that Support must be found by
introducing into the equation of the Elastic Curve the condition that the
slope (t) of the ' neutral surface ' at that Support is to be zero.

But this Case is not of sufficient importance to require development
here.

23. Restriction to Uniform Beams. — It will be seen that all the

worked Examples of this Paper depend ultimately on the Theorem of

Three Moments, and are therefore applicable only to Uniform Beams.

A Beam of Uniform Strength cannot therefore with any real propriety

be designed by the detailed Results of this Paper.

[The practice of many Engineers has been to take the Shearing Forces and Bend-
ing Moments assigned in this Paper, and design the Croaa-sections to suit them all
along the Beam ; it was supposed that this process would give a Beam of approxi-
mately Uniform Strength. But this gives a Beam of variable Section, and
therefore violates the very first Step in the integration of the Elastic Carve (that in
which " I " was taken to be constant throughout the Beam). It appears extremely
doubtful whether a Beam so designed is really a fair approximation to one of Uni-
form Strength, except when the Weight of the Beam is small compared with the
External Load.

The proper course in design of a Beam of Uniform Strength would be to investi
gate the question de novo, introducing the condition of Uniform Strength into the

136 CONTINUOUS UNIFOBU BEAMS.

integration of the Elastic Carre at the outset This would completely change the
form of the Results. Its complete solution has not yet been discovered].

24. Economic Spans. — The as yet solved cases of Continuous

Beams being only those of Unifobm Section, the scantling is of course

really determined by that necessary solely for the

(0), — absolute maximum Bending Moment, Ma.
(ft),— absolute maximum Shearing Force, Fm.

Now the latter (b) is almost always > the corresponding quantity in
discontinuous Spans, so that unless the former (a) be markedly less than
the corresponding quantity in similar discontinuous Spans, there will be no
advantage whatever in continuity.

Thus, comparing the Result of Ex. 7 (Ms =2 — \ wc*) with the well
known Result for " Supported (discontinuous) Beams ", ( Ma =r £ wl*)
it is seen that,

<< Continuity is disadvantageous in a Two-Span Uniform Beam uniformly I ^ ^
loaded" J

In determining scantling, the magnitude of Mm is however of much more
importance than that of Fm. And the absolute maximum Bending Mo-
ment (MB) is — when the number of Spans exceeds two— usually less
{see Ex. 7 — 11) than in similar discontinuous Spans, so that there will be
eome advantage in continuity in such Cases.

There is obviously— for a given Load— some arrangement of the Spans

(Zl9 lvlv ) which makes the maximum Bending Moment less than

any other, and this is — cceteris paribus— \he most Economic arrange-
ment.

To find this, observe that this quantity (M») is expressible as a func-
tion of the several loads (10,, wv <fcc.) which are given, and of the several

Spans ( llf /„ <fcc, ) ; the sum of the Spans (/, + J, + &c ) is

of course a given quantity ; hence their ratios are to be determined so
as to make M» a maximum, a problem usually solvible by the principles
of Infinitesimal Calculus.

E*. Uniformly loaded Symmetric Three-Span Beam (^ ■- l# wx — nr9 ■» wj

By (76), M. = M, -- ?.^±^,and 2/, + % -constant
Hence the minimum of MB is given by—

— .-£— L-2- m 0 .and 2 4- — 2 at 0

whence on reduction 10// + 9// 1, - 12// - HJ/ — 0

COHTIMUOUS UNIFORM BEAMS. 137

or (£)' + -9 (j*)' - 12 J -1-4=0

from which it will be found (on trial) that /2 « 1*164 *,«**.

This arrangement of Spans is therefore the most economical.

[This differs so little from equal Spans that the saying is of course very small :
thus it may be shown that, (if L "" vam °f Spans),

1°. Economic Spam, (continwnu) ; MB = - -0109 tc\J.
2°. Equal 8pan§9 (contitwoui) ; M« — — •0111 w\J.
8°. Equal Spans, (dUcontinuous) ; MB — + -0189 *>[/].

25. Economy of uniformly loaded continuous equal Spans.— It was

Bhown (Art. 24) that in Uniform Brums the economy ifl in strictness

limited to that dne to the redaction of the absolute maximum Bending

Moment (MB) from its value in a discontinuous Span. The proportionate

reduction is shown in following Table : —

Bbam.

RsfBrance*

Value of Mm.

PioportloiMt.
BMucttonof

Discontinuous Spans, •• •• . .

■

-f-i 190*

'Two equal Spans, •• ..

Eg. 7, Art 19,

-i wc*

None.

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Ew. 8, Art. 19,

-f «•*•

*.(»«**)•

Four equal Spans, • • • •

E». 9, Art 19,

-f we*

f. (1 «•«*>•

Five equal Spans, •• ••

Ex. 10, Art 19,

-*«"»

Att-c").

^Six equal Spans, • •

E*. 11, Art. 19,

-««**

Ad-**).

26. Advantages of Continuity,— This Paper shows that the ge-
neral effect of Continuity over the Supports is the shifting of the sec-
tions of maximum Bending Moment to the Supports which is usually
accompanied by a reduction of the magnitude of that maximum Bending
Moment, and therefore, also by a reduction of the maximum (longitudinal)
Stress-intensity, and maximum Deflexion.

This is clearly in general attended with great advantage as far as econo-
my of materials is concerned, especially in expensive material like iron.

This advantage is usually greatest— (1) with symmetrical cross-sections
(i. e., cross-sections alike above and below), and (2) with Steady Load.
These conditions deserve careful attention because in some cases Continuity
is positively disadvantageous.

Thus, observing, that Continuity causes opposite curvatures in parts of

188 CONTINUOUS UNIFORM BEAH8.

the same Beam, and that under Moving Load this cnrvatnre varies, and is
liable to be reversed, it is clear that a Continuous Beam must be suited
(even under Steady Load) to act in parts as a Cantilever and in parts
as a Supported Beam, and within certain regions (under Moving Load)
to act as either alternately.

Hence in a Continuous Flanged Girder different parts of the same
Flange are in Tension and Compression, and under Moving Load certain
parts of each Flange, as well as certain parts of the Bracing or Web are
alternately in Tension and Compression. It follows that —

" A Continuous Uniform Beam is seldom advantageous

(a), with Cross-sections of Equal Strength, .'. ^

(6), in Cast-iron, M ^ l...M(112>«

(c), with heavy moving Load", J

It is also utmally considered that there is little* advantage in Continuity
in Short Spans under 150 feet.

A. C.

* Stone?*! Theory of Strains, Art. 2M.

TABLES OF RAJBAHA VELOCITIES AND DISOHAROE8, ETC. 139

TABLES OP RAJBAHA VELOCITIES AND DISCHARGES

FOR SIDE SLOPES 1 TO 1.

Computed for the Punjab Irrigation Department, under superintendence
of C apt. Allan Cunningham, R.E., Hony. Fell, of King's Qoll. Lond.

These Tables have been computed from the following data and formulae : —

Required, —
A = Area in square feet
R = Hydraulic Mean Depth in fret.
V sa Mean Velocity in feet per second.
D ss Discharge in cubic feet per eeoond.

C ss Co-efficient in formal a V=C. v'RI

Data,—
Channel, earthen.
Section, trapezoidal.
Side-elopes, 1 to 1, or 45°.
h as bed-width in feet
d = depth of water in feet
/ ss fall of channel in 5,000 feet in feet

Formulm used in computation.

A = (» + «<W, R-r+^sa

V= . 2R . ■/? , D = A.V.

«• 7 + 1-7066 B /

I
C = /W008688 + '°0086-

■/

The formula for V is modified (to a form suited for computation in Tables) from
one given in the " Professional Papers on Indian Engineering ", [First Series], No.
CXCVTL, (by the late Lieut-CoL J. C. Anderson, R.K.), 4th type of Table I.,

?— = -00086 (-2488 + g)

as suitable for channels whose " Bed and sides are of earth". This formula is sim-
ply adapted to English measures from that given by M. Basin in his " Recherches
Esperimentales snr 1' ecoulement de l'eau dans les canaux decouverts M.
The Coefficient C (which forms the last column of the Tables) is simply the square

root of the reciprocal of •00035 (*2488 + g), so that UsC s/RI, whence also

VssC. /Rz^LorssCyRI.
J 5000

[These Tables have been prepared throughout by two* independent computers.
The numbers in the columns of " Areas " are emaet. The numbers in the columns
of B, V, D, C were in every case computed to at least one more decimal than is now
printed \ and the first differences were examined by the Author himself.

From the fair regularity of these differences, it is believed that the last figure does
not err by more than 2 in any column]. A. C.

• Pandit Chhote Lai and Lala Gang* Sahay, Ant. Maitm in the Thomaaon C. E. Colleg*.
VOL. V. — SECOND 8ERIK8. U

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TIMBERING Of KMT HOOTS. HJ>

No. CXCL

TIMBERING OP PENT ROOPS.

[TO* Plate XXU.].

Bi Majok W. H. Mackbst, F.G.8., Assoc. Inst. C.E., Aat.
Secretary, P. W. &., Punjab.

Thib Article is written in continuation of No. LVIL, Professional Papers,
Second Series, on the " Timberirig of Flat Roofs, " and deals chiefly with the
most economical arrangement of Rafters, Purlins and Trasses for Pent
Roofs — conyenient rales for obtaining the scantling of common rafters and
purlins are also given, as well as for the scantling of under-trussed girders
for flat roofs. A table of breaking weights for square deodar pillars is
appended. This table was computed by Lalla Goorsahai, the head of the
estimate department and drawing office of the P. W. Secretariat, Lahore,
to whom the writer begs to express his obligations. A note is added,
giving an exact expression for the most economical spacing of the beams
of a flat roof. The notation generally is that employed in Thomason
College Manual No. IIIa. (Applied Mechanics). •

w= uniformly distributed permanent load per running foot of beam, &c.
«/=normal wind pressure per running foot of beam, &c,

W = wL.

W = u/L.

2. The general results of the investigations are as follows :—

It is shown in paras. 9 — 11, that the scantling of a common rafter may
be computed by the strength formula as that of a horizontal beam of the
same bearing loaded uniformly with w + wx.

3. It is shown in paras. 12 — 15, that the scantling of a purlin, or hori-
zontal rafter, may be computed by the strength formula, as that of a hori-

150 TIMBERING OF PENT ROOFS.

zontal beam of the same bearing, with vertical sides loaded uniformly with
nw + u>n also that in ordinary cases n may be taken = 1*5.

A general formula (Eq. 2c) is given, from which the value of n can be
found under all circumstances.

4. The general problem of the most economical arrangement of the
timbers of a pent roof is investigated in paras. 1 6 — 23, but it is to be under-
stood that in all cases whether in flat or pent roofs, economy of con-
struction must give place to structural requirements.

5. It is shown in paras. 20 — 22, that it is a wasteful arrangement to
carry the common rafters of a pent roof directly on the trusses, and some
practical suggestions are offered in paras. 23 — 28, regarding the best ar-
rangement of purlins and the type of truss to be selected in any parti-
cular case, as well as the best arrangement of joint at foot of principal
rafter.

6. Expressions are given in paras. 28 — 41, for the scantlings of the
principal rafters of trusses carrying common rafters directly, and for the
scantlings of under- trussed beams carrying a flat roof; the principals and
beams in such cases are under a double stress, from the longitudinal thrust
and from the transverse load. Failing an expression for the deflection
of a beam under the double stress, no exact solution of the problem is
possible, the following has therefore been taken as the host approxima-
tion at present attainable.

Fig 1. 7. If AB be a rec-

tangular beam subjected

q p to a thrust in the direc-

r tion of its length, the

1^3 V

"W< W proper scantling can be

determined from the rules in the text-books. Let it be assumed that AB
has such a scantling ; if now a weight W is placed on the beam, the origin-
ally straight axis is deflected more or less, the thrust T causes a still
further deflection, and the frame of whioh AB forms part, is rendered
liable to failure. If now we increase the scantling of AB, so that it
may have an excess of strength and stiffness under T, we may safely apply
a load W, provided that no part of the beam is thereby exposed to a greater
stress than before. There must always be some deflection caused by W,
but if this condition be fulfilled, it seems probable that it will not be in-
jurious.

TIMBKBIHQ OF PENT BOOF8.

151

8. The method followed is to determine provisionally the uniform
stress on the fibres of a pillar of sufficient scantling for the thrust, and
then to increase the scantling so found, until the maximum stress on the
extreme fibres of the new beam from the transverse load, + the uniform
stress from the thrust, do not exceed the uniform stress on the fibres of
the provisional pillar — when, however the pillar is smaller than a beam
stiff enough for the transverse load alone, the scantling of the latter is
increased, until the maximum stress on the extreme fibres of the new
beam + the uniform stress from the thrust, does not exceed the maximum
stress on the fibres of the provisional beam. In no case should the com-
bined stresses exceed /« -f- 10.

Common Rafters.
9. If the rafter is free to slide at B, (t. e., not securely spiked) a safe as-

Fig.2.

sumption to make the whole of the thrust
along the rafter is taken by A, and when
under a uniformly distributed vertical load
w — this thrust increases uniformly from B
to A — and at any point c distant x from B,
ss xw sin 0y and the uniform stress on the
fibres at c

0 . 19. sin 0

d.b

Also the bending moment from the part of the load resolved at right an-

gles to the rafter at c = M = — j

the moment of resistance of the rafter at any point e = — g —

•• / — a.*

/ being the maximum stress on the extreme fibres. Now to make/ + p
a maximum, we have

*.v.sin0 , 3* (I — x) w cos 0 ma

d.b + =» M'

x . w . sin 0 . 8 *lw cos 0

d. b
sine -f

81 coa 0

8 gHgcosO
M5

ss tft.

&r cos 0 du A

— d — -'s!= U*

A * = tan 0 . -j- + -y

152 TIMBERING OF PBNT BOOF6.

In ordinary cases, tan 0 — will be less than one inch, and as part of

the longitudinal thrust will always be taken at B, it may be safely as-
sumed that the maximum stress in the extreme fibres occurs at the centre
of the rafter.

10. Take a very extreme case — a deodar rafter 10 feet long — pitch
60°, 10 = 50, wl = 40, thrust a 50 sine 60° = 43 0)8., transverse load
= 50, cos 60° = 25 fte.

Then for the transverse load alone—

The thrust in the ease of a common rafter is always very small, and it

will therefore suffice to add to the width on account of it.* The requisite
addition is— x 43 x^ 4.g = 0*102 inches, an insignificant increase;

we may, therefore, always neglect the thrust — and the exact formula for a
common rafter is (making the sides in the ratio of 2 : 3)

= */ 20 & •

COS 0 + 10|) «*

For roofs of moderate pitch and loads of ordinary occurrence, to + wl will
exceed w cos 0 + wxw but slightly. In the above example, if the pitch

were 80°, bcP r= B-^~ = 83, or neglecting cos 0, = ^55^ = 90, re-

presenting respectively scantlings of 2'f x 5'£ and 3' x 5'£.
We may, therefore, in ordinary cases make

» - 1/20 (V/» * -<">

1 1 . This rule gives ample stiffness under the permanent load. For, take
an extreme case — a deodar rafter, to = 25, wx c= 40, L = 10 — the coeffi-
cient of safety required to give sufficient stiffness under the permanent

load is 282g * ^ = 26, J and the actual factor of safety is H^22 = 26.
It seems wasteful to use the deflection formula for the whole load

* 5«« Professional Papers on Indian Engineering, [Seoond Series,] No. OXXI., Eq. 9.
t As in the former Article, « = distance apart of the purlins from centre to centre.
% 8— Professional Papers on Indian Engineering, [Seoond Series,] No. LVII.f Eq. 14.

TIMBERING OF PENT ROOFS.

153

w + wl9 as it is only daring dust storms in India, lasting but a short
time, that the wind is at all violent. A fife feet rafter 2" x 3* with this
load (65 lbs.) would only deflect 0-188 inches at the centre under the
most riolent wind — it is shown hereafter that common rafters should never
be longer than about five feet. It is thus only when long rafters are U6ed,
that their scantlings need be determined by the deflection formula, and in

such cases, a deflection greater than —-inch per foot of span, seems to

be fairly admissible.

Publinb.

12. Let W be the permanent vertical load (omitting wind pressure)

^9* '• i ^\ acting on a pur-

lin, at one side
of the centre of
gravity g. This
force is equi-
valent to a
force W acting
through g, and

to a couple whose moment = W . fg = W, X ^ x sin 0.*

The effect of W through g will first be considered.
The moment of resistance of a rectangular beam = — zz M, also 0 be-
ing = the slope of the rafter, we havef

T d*b oo8«0 + I'd sin'fl
l5== 12

y = _i2? — ± — !1IL_ = the distance of the furthest point from
the neutral axis.
.-. M = {.M {***" + ?**).

6 \ d cos 0 + b sin 0 /

If we put

d = rb, we have

M = ^ ry co*'9 + r*8 tAn'9 — J* h

6 ' r cos 0 + sin 0 ~" 6 '

for sections of equal strength, putting bd* =s A = r*^

* EflakbM, W. M., Art. 42.

t BanUiM, W. M.t Art. 96, Bq..9.

154

TIMBERING OF PENT ROOFS.

M = ^-r- . . tr . . , equating the first different coefficient to

6 r cos 0 + sin 0 ' ^ °

zero, we have r = tan 0 (1 di /s/2) makes M a minimum — for a pitch of
80°, r = 1 *39. (This result serves to show that the maximum, r infinitely
great, is unattainable). A greater yalue of r than 3 : 2 is not to be re-
commended.

The following short table of the values of k is useful for purposes of
comparison

/ jfc — r ffJ C08*g + gil1*) )
V r cos 0 + sin 0 '

<f-7-ft = r.

Values op 0*

80°.

«».

60°.

1'5

2-286
1-616
0-782

2723
1-642
0-718

1*592
1-878
0-707

1-876
1-212
0782

13. Let us now consider the effect of the moment of torsion ; this for
an equally distributed load = £Wx£dsin0 over the principal and
vanishes at the centre of the purlin, and unless the latter is treated as a
continuous beam, may be neglected.

Call the length of the purlin, I,

i, its Qepvn, •■• ••• ••• ••• o,

„ the equally distributed permanent load, W,
we have (see Rankine's Civil Engineering, Eq. 2, Art. 174),

T=s0 X x X sin 0 = — |^- . The value of M will depend on the

A lb *

number of points of support over which the purlin is continuous — then
M, = i {M+ VM' + T>j=:.5£ {l +V1+(TtM)j}

The complete equation is

Ifc.^.f-SJE, (2),

whence neglecting c, and putting M = Wl H- 8

Wl.a

*• =

2ipkJ

<**

TIMBERING OF PENT ROOFS. 155

for factor of safety = 10, 0 = 80°, r = 1*5, 12L = /, this becomes

¥ = w^ (2ft)

If the sides of the beam were vertical, the ordinary formula would apply,

m _ btP.f

whence

b = -?r>

hence Eq. (2a) may be written (putting c as before = 10),

*=* ^^i where n = -^ (2c),

for 0 s 30°, r = 1-5, n = 139,
6 = 85°, r = 1-5, n = 1-46,
0 = 45°, r sa 1-5, n = 168,
we may then take n = 1*5 for ordinary cases, leaving higher pitches than
35° out of consideration.

Since the wind pressure wx always acts at right angles to the roof,
for to,, 0 = 0, and h = r*,
we hare from Eq. (2c) for purlins

v — ^ — ; ' ' ( )•

For pitches up to 85°, r = 1*5, this becomes

The scantling so found gives ample stiffness under the permanent load.

5» + «i>^ (3a).

_ 3/20(1-

14. For example, take a deodar purlin 12 feet long under permanent
load 40 lbs., wind pressure 40 lbs., if s = 4, \\w + wl = 400 lbs. The
factor of safety* required to give sufficient stiffness under the permanent

load 240 Sbs., is **^ x *^9 = 135, the actual factor of safety for the

permanent load is ~ — ■ = 16*6, we have taken an extreme case, a

very long purlin with a heavy permanent load; it iB obvious that in
ordinary cases the question of stiffness need not be considered,

15. No reduction of scantling is admissible on account of the addi-
tional strength given by the partial continuity of purlins or rafters over
one or more trusses. The condition cannot be certainly secured for every
purlin and rafter, either in first construction or in subsequent repairs, and

* ProfMrion&l Paper* on Indian Engineering, [Second Serial,] Ho. LVII., Eq. 14.
VOL. V. SECOND SERIES. Y

156 TIMBERING OF PEMT ROOFS.

further, purlins and rafters should always be notched down on the support-
ing principal or purlin.

16. To determine the spacing which gives the least possible quantity
of timber in Purlins and Rafters.

Call as before spacing of purlins = length of rafter, s,
„ length of purlins, ... ... ... L,

„ load per running foot of rafter, ... ... w + wv

„ cost of Purlins per cubic foot, ... ... V,

„ „ Rafters „ ••• ... v,

„ d -r- 0, for Purlins and Rafters, respectively,... R and r,

we have for any beam from the strength formula,

„ 6WL*

W being the load per running foot.
The area of section in square inches = a = re" =s (— ) * (~)

putting c = , the cost = CVW L r

ntvlii

P¥XH4
1

8102 l«-* =

For deodar c =

„ r = l-5,#r =1-1447 J
Then we have the cost per running foot (measured along the slant)
of one bay.

Rafters, — . cvr~* (w + wj* a*

= Lew""* (w + u>i)* a* = Aa*

Purlin, \ . cVR-*| (nw + «?,)*}* L*

a L* cVR~* (nw + wt) * a~* » Ba~*
Equating first diff. coefficient of As* + Ba~* = u to zero, we hare

Now in ordinary cases V = t?,and R = r, also (j)T= 0*43528 = ^sg?
for w = 10, wx = 40, L = 5, n = 15, a = 1*639,
for to =s 40, wl = 40, L =s 12, n ss 1*5, a = 2-789,

These are extreme cases — we cannot practically use so small a scantling of

TiniRIKfl OF MCNT ROO*S« 157

common rafter as l*-36 x 2*-04,# the smallest section admissible for deo-
dar is 2* x 3*, and if the purlins are placed closer together than the
spacing which this section of rafter can safely span, there is of course
waste. Assuming a section 2* X 3" for the common rafters, the most
economical spacing of purlins is as below

„ + Wl = ibs.,50 60 70 80 }fordeodar.

b = feet, 6 6-48 507 4*74 J

About five feet is thus the most economical spacing for deodar purlins
for ordinary roofs.

17. To compare the cost (leaving the trusses out of consideration) of
rafters and purlins and of rafters laid purlinwise, (horizontal rafters,) we
bare

Cost of one horizontal rafter (calculated as a purlin) —

=r cv (nw + Wj) r~ L = a,
Cost of a bay of rafters for one running foot —

= Lew (u> + wx) r 9 = b,
Cost of purlin for one running foot —

= s"1 cY(nw + w^s* B~* L* = c,
then putting a = b + c, we have the spacing of trusses at which the

cost is equal = L *= (!L±JZl\*. * * R , (5).

If we pot v = V, and r = R, this becomes

L = (_£±fl)* <* (5a).

{t*2 = 40 40 40 40 fibs.,

w = 10 20 30 40 flte.,

then / ~ +»■ = -9535 -9258 -9070 -8944,

>/ 1-5 » + w,

and if we take * = 6 5*5 5*0 475 feet,

then 1 = 10-927 10-295 9667 9354 feet.

• »/»•» x 80 x tn' - i-M,
J — HO

158

TIMBERING OF PENT HOOFS.

From the above factors

taking $ r= 6, w c= 10, tvt = 40,

we have L = 10-927 x -9535 = 10*4 feet,

and taking a = 4*75, w = 40, wl • =s 40,
we have L = 9*354 X -8944 = 8*35 feet, thus so far as cost of the timber
in purlins and rafters is concerned, it is more economical to use horizontal
rafters for truss spacings less than L as fonnd from Eq. 5.

18. We will now proceed to investigate the question of the most econ-
omical arrangement of roof timbering, taking trusses, purlins and rafters
into consideration.

Each principal rafter of a timber truss is under a thrust in the direc-
tion of its length, and its scantling must, as already explained, be deter-
mined as that of a pillar under the same vertical load. Let AD, Fig. 4
or 5, be a principal loaded at B and O by purlins, and strutted under each
purlin* The thrusts on the sections 1 , 2 and 3, are approximately as
those numbers. Now AD is rigidly fixed at B and G by the purlins above,
struts below, and by the purlins laterally ; if we suppose the thrust to be
so great, that the section AB is just on the point of bending, the section
BO on which the thrust is f of that on AB, and still more the section
CD, has a considerable excess of rigidity, it is also obvious that any flexure
in AB causes a simultaneous flexure in BG and GD. We see, therefore,
that under such a load, the mean fibre at B is fixed in direction, while
the mean fibre at A is free to bend. The section AB must therefore
be considered as a pillar fixed at B and free at A.

19. Gordon's formula the coefficients used with which are based on
Hodgkinson's extensive experiments, is the most trustworthy formula
extant for determining the dimensions of pillars, it gives a larger scant-,
ling for timber pillars than Kondelet's formula, which is frequently used in
India. The discontinuity of the reciprocals of Rondelet's multipliers (which
will be seen by taking the second differences) alone suffices, show that
his formula is not correct.

Timber post, both ends fixed.

Ratio I -r d.

Rondelet'a multipliers and their Beciprocali.

Oordon'e Dirton,

1-2

1-57

2-0

8*80

10-2

16*4

21-7

•

TIMBERING OP PENT ROOFS. 159

Gordon's formula is P = 10T = fcA ■

i+cj

where A =z area of section = <P for square pillars.

mn^ C — q w oRn ror dry timber for pillars fixed at one end

_ 1

~~ 140625

whence for square pillars eP = —• J 1 ± / 1 -j- °*4 & p c l

A Table of the values of 10T = P for square deodar pillars is append-
ed. It can be made applicable to any kind of timber or area of section.
Taking as examples extreme values of I and T, we have for deodar

1 ± J 1 + 2±^iL£ equivalent to 2-066 when (Z= 12, and T= 18,000).

and to 2-018 „ (J--4-5, „ T= 9,500).

In cases of ordinary occurrence, we have therefore d*, or the sectional
area of the principals, approximately proportional to the thrust, which is
directly proportional to the spacing for any given span and pitch, and
similarly for the struts. The areas of king post and tie-beam are directly
proportional to the spacing. Hence, we have the timber in a truss for
any particular span and pitch, and consequently the cost of the truss
approximately proportional to the bearing of the purlins.

20. If therefore the same scantling would answer for the principals,
whether the trusses were intended to carry purlins or horizontal rafters, it
would be cheapest to use horizontal rafters of the smallest admissible
scantling, spacing the trusses at the corresponding distance apart ; [we
find however, see paras. 29 and 80, that a considerable increase of scant-
ling is required for rafter trusses.] These spacings are given in the
following table for deodar for various values of wx and to, (calculated
from the formula for purlins).
w wl

10 40) (5-72 feet.

20 40 / Maximum bearing of horizontal \5.Q7

80 40 [ ra^ers °f deodar, scantling \ £.£q

40 40) *" X *"■ (-4-24 ",

We have then the following problem to solve — at what spacing of pur-
lin trusses will the cost of timbering be the same as if rafter trusses

160 TIMBERING OF PENT ROOFS.

were used ; the rafter trasses being spaced to suit the minimum section
of rafters.
21. The general solution of the Problem is as follows : —
Put length of room to be roofed, ... ... ... =s /,

„ number of divisions in the purlin trass, ... ... = n',

„ „ bays in purlin trussed roof at which cost of truss-

es and purlins equals the cost of the rafter trusses, ... = N,
„ approximate cost of one purlin truss, ... ... = P,

„ for a provisional number of bays, ... ... =s v,

„ cost of the rafter trusses required for the room, ... = R.

The spacing of the rafter trusses must be that which suits horizontal
rafters of the same scantling as the common rafters of the purlin roof,
so that in either case, the quantity and cost of the common rafters is the
same.

In order to obtain P and R, rough design and estimates must be made
for trusses for the particular span to be roofed, and style of roof covering
proposed.

We have

R = ~ . P (N — 1) + In' X cost of one purlin.
The cost of a purlin trass per running foot of bay = P X -r, and cost of

all the pnrlin trasses required = (N — 1) P . -y- . -g- = -jj- (N — 1).

(It is assumed that the two pole plates and the ridge pole are together
equivalent in cost to two purlins).

Also the cost of one purlin = nj • { _| ■ / -jjr =

.-. R = -^- . P . (N - 1) + n' .

■* ** + rSp • N* - *=£ - o (6).

Whence N can be obtained by approximation.

Example.—* A room 25 feet span and 48 feet long. Pitch of roof 80*
tv = wt = 40 fibs., n' = 4, V = Rs. 1-8-0.
For a spacing of 8 feet, a purlin king post truss of deodar timber at

TIMBERING OP PENT ROOFS. 161

Rs. 2-8-0, would cost about Rs. 60; the principals being 6} inches
square.

Whence P = 60, t* = -^ = 6.

For a spacing of 4 feet, a rafter truss, the principals measuring 8£" X
5£", would cost about Rs. 50, whence

— 50 x ( " - l) = Rs. 550.

Then

N* , 6 X 60 x| _ 61 X 04324 x 8378* _ Q

■*■ 650 - 860 * 190 '

and ^ + 1«9N*- 7-448 = 0,
whence #N = 1*51145, and N = 8453.
There may be four bays of 12 feet each in the length of the room.
The scantling required of each purlin for bearing of 12 feet is 7"*7 X 11"* 5

, »'20 X 100 X 71 X U4

V » X 500

b = 7*688 inches,

d = 1*56 = 11*532 inches,

spacing of purlins = ~? = 7*1 feet.

We hare then, cost of purlin trusses and purlins, —

Purlins, 4 x 48' X IL±£* x 1-5 .-. = Rs. 177

Trusses, 6 * ™ * 3 = „ 270

Total, „ 447
The coat of the rafter trusses being Rs. 550, it follows that trusses
and purlins would in this case cost the same as rafter trusses, at Rs.
4G-10 each, instead of Rs. 50, as assumed.

22. We see from this formula and example, that it can never be
economical to carry the common rafters directly on the trusses. If the
rafter trusses are spaced further apart than indicated above, stronger raft-
ers are required ; the quantity of timber in the rafters increases as the
cube root of the fourth power of their bearing. For instance, the quantity
of timber is doubled if the bearing is increased two-thirds (the exact pro-
portion is 1 : 1*682).

162

TIMBERING OF PINT ROOFS*

23. It follows, therefore, generally, that the moat economical arrange-
ment is to space the trusses carrying purlins at a moderate distance apart,
not too close, in order to reduce the cost of labor and of erection. Probably
9 to 10 feet is the best distance, but the problem does not admit of an
exact solution in the absence of an expression for the exact value of P in
para. 21, see also para. 19.

24. Two or more purlins are sometimes placed at either side of the
struts of a king post truss, thus bringing a transverse load on the prin-
cipal ; this should never be done, unless the permanent load is very small.
There should be a strut under each purlin, and this is always practicable.

Fig. 4.

Fig. 5.

25. It has been shown that the most economical spacing for purlins,
is that which the smallest allowable section of common rafter will safely
span — about 5 feet, say 4 to 6 feet in ordinary cases. The ordinary king
post type of truss can, therefore, be employed up to a length of principal
of about 12 feet, equivalent (for a pitch of 80°) to a span of say 20 feet.
The type of truss, Fig, 4, or the queen post type with one strut, should
be employed for spans of from 20 feet to 30 feet, or for lengths of princi-
pal from 12 to 18 feet, and finally the type of truss, Fig. 5, for spans of
from 80 to 42 feet, or for lengths of principal from 18 to 24 feet Suitable
designs for types 4 and 5, and for queen post trusses with one strut, will

TIMBERING OF PENT ROOFS.

163

be found in the Roorkee Treatise, Vol I., 1873, Plate XXX., Figs. 6, 7,
and 8, and Plate XXIX., Figs. 2 and 3.

The stresses for Fig. 4 will be found in Plate LXVL, and for Fig. 5
in Plate LXVTL, slightly modified when there are two strata.

26. Having decided on the spacing of the trusses and their type, deter-
mine the stresses in the various parts. The scantling of the lower section
of the rafter is calculated as that of a pillar fixed at one end and free at
the other, and the scantling of the struts as pillars free at both ends. Or

the scantlings of both rafter and stmts can be obtained by inspection

from the table of posts.

27. The most important joint in the trass is that between rafter and

tie-beam, — it is best designed as follows, see Fig. 6.

Fig. 6. T*1* fig010 w-

f' presents a joint at

foot of a principal

*>¥ X 6}', throst

= 16,868 lbs., and

tension on tie =

14,900 lbs. = 8-7

tons. The area of

. . . 16868

J°int = Tooo =
16*9 square inch-
es,* and its depth

8X1*9
00 2x6*5 —

89*1 inches, say 4
Scale, ^th full Hz*. inches. Its posi-

tion is thus found — bisect the wall plate by a vertical line db, draw any
line dd! at right angles to the direction of the pitch of the rafter, make it
4 inches long, bisect it in b\ draw c'cd' and Vb at right angles to ah, and
draw dbd parallel to cVf through 6, and make cd = <fd\ then cfcc* is the
top of the tie-beam, and cd the joint. Draw W at right angles to cd
for the axis of the principal, and draw u' and ff at equal distances

• The width (0) of the bridle em to *} the width of the tie ; If the bridle to omitted, end a tenon

16*9
4k given on the principal, the whole nxrboe to effective, and cd = — = *« inobw, effecting a

wring of timber in the tic—the tat arrangement to preferable.

VOL. V. SECOND SERIES. z

164' TIMBERING OF PENT ROOFS.

at either side of W and parallel thereto for the bottom and top of the
principal Join ed. (This construction makes the resultant of the reac-
tion at the joint pass through the axis of the principal — a necessary
condition to secure its full calculated strength). Draw <Td at right
angles to 6a. A notch (csf in elevation, ms' in plan) may be given in
the bridle, sc may be from £ to J cd.

14*900

The area required for the tie is square inches, and the width being

14900

6£ inches, the depth must be not less than j^t — — = 8*25 inches — 1£

inches additional may be allowed for notching on wall plate and for con-
tingencies, total 4*5, which is set off from d* to a, making the total depth

14900

of tie 8 inches. Set off eg, dk each equal to ^ — ^ = 15*8, say 16".

Draw gg* and kVk" at right angles to gccf, the tie is cut off at gg'.

Set off V V ss £ depth of tie — 1 inch, and join ck\ which gives
the bottom line of the strap. The tension on tie when resolved, gives
a tension of 9 tons on the strap, or 4*5 tons on each side ; allowing a
thickness of f * and 5 tons per square inch, the requisite width of strap is

tjL*JL = 1-44 inches, say 1* inches, (ljff X f"). Set off e/at right

angles to cV for the abutment of the strap. The safe shear on a round bolt
l£" diameter is 5 tons, and the strap should be secured to the tie by a bolt
of this diameter. The centre of the bolt hole should be on the line c' V.

The horizontal component of the thrust along b"b tends to bend down
the end of the tie, and brings a cross strain on da. In the form of joint
shown in figure, the bridle in the tie (cde in elevation, mn in plan) helps
to resist this action. In heavy trusses, there should in addition be a
small wall plate at the end of the tie-beam.

28. King post truss with uniformly distributed load, see Fig. 7. If
x ss the distance of any point p from V, we have the thrust at p = tea
sin 0 + the thrust resulting from the permanent load and wind pressure
acting at right angles to the principals, + the thrust produced bj the
weight of tie, struts, king post and ridge acting at Y. Since AV is
a continuous beam, bisected and supported at B, we have portion of W
acting at right angles to rafter at A* = -& wL cos 0,

» ,> » » B =|jf u>L cos 0, }...(!!}.

„ „ „ „ V = ft wL cob 0,

• Stowy, Bq. 172-3.

TIMBEBING OF PENT ROOFS.

165

The exact expression for the total thrust at any point in AV is compli-
cated, and is separately investigated in Note A at end of this Article.

Considering AV as tinder a thrust alone, each section AB, BV, may be
treated as a post fixed at one end and free at the other end. In conse-
quence of the lateral support given by the rafters and the action of the
transverse load, deflection can only take place downwards, and the princi-
pal is solicited to assume a curve A^eeB'eeV ; hence d in Gordon's
formula is the depth of the principal.

As a provisional scantling, we have from Gordon's second formula, putting
AV = L, and making the breadth of the principal two-thirds of the depth

) c),

*-¥■<}* j* +

f*U

14-648 T

or for deodar, dx can be obtained directly from the table of square pillars
fixed at one end and free at the other, by entering the table with P =
15T, and L = half length of principal.

Then the uniform stress on the provisional pillar

1-5 T _1 £

■j

i ± / 1+

/«L»

.(8).

U-648T

29. Considering AV as under a transverse load only, it may be treat-

Fig. 7.

ed as a continuous girder of two equal spans loaded uniformly.* The
greatest bending moment is at B, and the maximum stress on the extreme

fibres at this point =/„ = *™ (* «*' + "»> V also the maximum com-

bined stresses at B must not exceed /, + fn =f. Let bd be the scant-
ling required, then /, = T-rM, whence for the general equation we have

• Stoney'fl Theory of Strains, page 161.

166 TIMBERING OF PENT ROOFS.

« T . 2-25 (nt cos 9 + »Q U /Q.

'=« + w* — ; — w

If d is assumed

* _ T / ! . 2-25 (w cos fl + *i) I^\ /fl„\

If 6 is aesumed, we have

d=^ (i+yi+i>»^±^i) (w).

If d is assumed ss rb> we have

or if we make the ratio of breadth to depth of the principal = 2:8, (pro-
bably the most suitable ratio,) we have

ffi _ XU . d _ 3-875 (» cos* + »,)!.' = ^ (W}

30. Example.— A truss, pitch 85*, span 28 feet, spacing 5 feet, w
= tv, = 40 x 5 = 200 lbs., W = W, = 12-2 x 200 = 2,440, we
have the thrust at B (see Note A) = 4,900 Abe., and thrust midway be-
tween A and B = 4,900 — 850 =» 4,550 lbs. = 2-04 tons. Entering

the table under 6 feet, column 2, with 2<Hx^0*? = 80-6 tons, we have

the requisite provisional depth = 5£%
whence

/= sf?V=8ay256lb8-'

then

^ 1*5 X 4900 , _ 8-875 (1998 + 2440) 12-2 __ ft
a 256 256 ~ '

«P - 28-71 d - 718-8 = 0,
whence

d = 10 inches.

ft = 6* „
Proof—

2-25 x 4480 x 12-2 _ 1R7 _ _r max. stress on extreme fibres at
6* x 10x10 — widb. _ j b from the tnuisverse load.

4900 __ 72 = uniform stress from thrust.

10 x 6± 259 = max. stress on extreme fibres at any

point in the beam.

If the load were carried on a similar truss by purlins and ridge pole

over the trussed points, the thrust on the lower section of the principal

timbirino or purr roofs. 167

_ / «x2M0 + go© ) cosec 85°» )

^ } = 8,689 + 1,822 = 4,861 tt>s.,

+ ™ (8 _ ««,» 85') cot S5« j = 2.18 ^

The length of the lower section of the rafter being 6 feet, the principal
should be 4f ' square (see table) or an area (4 j)2 = 22*5625 sq. inches

against 10 x 6J = 68-8 square inches for the uniformly loaded truss,
showing that the latter requires much more timber than the former. The
arrangement is not a good one on this account, and should be avoided,
except possibly in the case of roofs of high pitch and moderate span with
a hght roof covering.

31. Simple symmetrical truss — load uniformly distributed, see Plate,
Fig. 18. The greatest stress occurs close to the centre of the principal at.
the side of the wind. First considering the principal as a pillar free at both
ends, calculate dx or take it out from the table, then /= V -*- bldr (In
this case, and generally if dx obtained from Gordon's formula, or from the
table, is more than one-tenth the length of the pillar— put/=/c -s- 10).

Again considering A'V as under a transverse load only (see Note B),
it may be treated as a beam supported at the ends and uniformly loaded.

The greatest stress on the extreme fibres is at the centre, and /„ =

• (* cos 9 -f w1) Lf x. a i as

— - — . -T — - — , then the general equation is

b and d being the required dimensions of the beam.
If we ««nme db = £ (l + »(-«»« + «0 » ) (10.).

Bweammie td=z j%-(*± /l + ** »<* ™9 +^&) {10b).

$2. In the case of this truss, the provisional pillar will usually be con-
siderably smaller than the provisional beam ; when this is the case,/ should
be deduced from the scantling suited for the latter, which has to be first

calculated, /= — a a%W — > or / can ^e calculated directly by
combining this formula with that for the deflection of a uniformly loaded
beam,

• ThomMon CItII Engineering College M*nu«i No. IUa, panes 567 and 666.

168

TIMBERING OF PENT ROOFS.

Bat if /bo found exceeds /« -5- 10, the latter value should be adopted.

33. Example. — Trass — pitch 85°, span 14 feet, spacing 5 feet, w=wl
= 40 X 6 = 200 As.

W = W = 6-1 X 200 = 1,220 fibs.

Thrust at centre of A'V = 583 fibs., the provisional beam is evidently
greater than the pillar,

/= 089 ^ ** x <2500)' = 877, this exceeds 6,000 -f- 10 = 600,

we therefore take/= 600.
We have then,

•. 1-5 x 588 , 18-5 X 864 x 86 A

* eoo- d 600 = °>

or cP — 1*46 d — 294*84 = 0, whence d = 6*8, and the scantling may
be 7" X 4±\

34. Inverted Queen Post truss with stmts DC and Dfiv Fig. 8. The
beam when loaded is solicited to assume a curve AeDeeD^B.

Fig. 8. '

+00

f 24»2-

■iOOO—

Considering A3 as under a thrust alone AD, DJ3, are in the oondition
of posts fixed at one end (D) and free at the other, while the central por-
tion DtD is in the oondition of a post fixed at both ends. The thrust
and section of the beam being uniform, putting AD = BDt = i, DD=JU
we have from Gordon's second and third formulas

/cA _ /cA

whence lx = -g I, hence in order that the sections may be^equally strong
under the thrust, the following proportion must hold

AD ( = BDt) : DD, : : 3 : 4.

Again considering AB as under an uniformly distributed transverse
load alone, in order that the mean fibre at D and Di may be horizontal, we

• TIMBERING OF FBNT ROOFS. 169

unit have AD = D,B : DD„ AD : DD, : : 1 : 2 V3 -f- 8 : : 31 : 38,
(putting tan fi = 0, in Stoney, Eq. 179).

The divisions of the beam may therefore be in the ratio of 3 : 4.

35. The distribution of the load is fonnd as follows: —

Patting AB = L and

R = reaction at wall plate

W = load at D,D,
we have*

.% B = 0-1078703 wh and W = 0-3921296 wh

also 2 (R + W) = wL. The positions of the points of inflexion are

marked in Fig. 5.

Hence T = °'8p + l x 0-892 t*L, (11).

also tension on tie = T ^1 + ( o-s l + 1 ) (11a).

36. From Gordon's third formula, we have for the provisional scantling,

8ft

putting d = -7p and remembering that the length of the central section

= HL

*,-Tr*C'*y> + *fr) m.

or d may be found by inspection from the table, which should be entered
with P = 15T, and L = 0-4 X span, then

/-§-!■ /iTA^"" (18>

37. The maximum stress on the extreme fibres from the transverse
load occurs at DXD, its value is

/ — yT, -, but the maximum combined stresses at DtD must

bldl

not exceed/, + ftl =/. We have, therefore, (6 and d being the scant-
ling required)/, = T -f- id. The general equation is

T . 0-912924 wl? /1JX

/= W + EF ' <14>'

whence assuming any convenient value for d, we have

l /T 0-913 wl?\
h = df\T+ — 5 h (14«)-

If b is assumed, we have

rf = £(l±N/l + 8-^) ("*).

If r is assumed, we have

* - y 7 — ==0' ^ 4c^

• 8toM7, S0.186-7-S-0.

170 TIMBERING OF TBNT ROOFS.

The maximum tension on the tie is given by Eq. 11a. In designing the
tie, it should be remembered that the iron obtainable in the Indian mar-
ket is is often bad in quality, and the actual load on fiat roofs may equal,
or even exceed, the intensity of 100 lbs. per square foot usually assumed.
This is more particularly the case with mud roofs, which are liable to
increase in thickness from year to year by the addition of mud plaster
or leeping. In the case of pent roofs, where 5 tons per square inch is
allowed for iron in tension, the permanent load falls far short of this
limit, which is only reached during violent storms.

88. Example.— Queen-post truss of deodar timber. 25 feet bearing,
depth 80 inches, w = 600 lbs.

Eq. 11. T = || X 0-892 x 600 x 25 = 19,898 lbs. = 8-9 tons.

Eq. 11a. Tension on tie = 8-9^1 + (II)' = 8-9 x 1188 =

101 tons.

One tie of If9 diameter would be required, with an addition for safety
according to circumstances.

Entering the table under column 8 with L = 10 feet, and P = 15 x
8*9 = 1335 tons, we find the provisional scantling is 9 J* x 6£*, whence

Eq. 14c. Putting r = 2, we have

,. 2 X 19898 , 0-918 x600x2x26x26 _ A
* 846- * 846 °'

or d» - 115 d - 1985 = 0.

Whence d = 15"-6 and b = 7"-8.

Or assuming d = 15"'6, we have
Vn i A» — l (\ QftQft J. -918 X 600 X 26 X 26\ _ -« .
E* 14a = 16-6 X 846 V19898 + Ifr6 ) " ' 8 nearly*

The scantling required for an untrussed beam is 21*»4 x 10*7.

89. A compound beam of a pair of flitches bolted together over dis-
Fig. 9. tance pieces, would be designed in a precisely similar

manner— the provisional depth would be obtained by
entering the table with 5rT, and / = gg on the re-
maining formulas of para. 87, b = 2f, and r= d -5- 2<.
The distance pieces must not be further apart than
10*, and each joints in the flitches should be at one of

the points of inflection, Fig. 5.
40. The use of under-trussed beams carrying the rafters directly, is

not to be recommended when wooden beams of the necessary stiffness are

TIM SEEING OF PKHT BOOF1.

171

obttinibJe, or when iron girders can be had at a moderate price. As in
the cue of pent roofs, it will frequently be found more economical when
trussed beams cannot be dispensed with, to carry the rafters on purlins
bearing on the trussed points. Take the example given in para. 88 — the
purlins would be spaced 8' 4* centre to centre, and the segments of the
trussed girder would be 9' 4* + 8' 4' + 9' 4* = 27 feet. Thrust 831
tons, tension on tie 8*62 tons, scantling required for a post 9' 4" long fixed
at one end for a thrust of 8*31 tons, is say 8£ inches square.
Quantity of timber in one bay — with purlins—

1 trussed beam, 27' X 8£" X 8£* — 13*6 cubic feet, »

2 purlins, ... 6' x 7*' X 4$' = 29 „ J ^22
6 rafters, ... 26' X 5" x 2£' = 13-5 „ I

Quantity of timber in one bay when rafters are borne on the girder.
1 trussed beam, 27' x 15£" x 7f* = 22-5 cubic feet,) Total 34*4
6 rafters, ... 26' x 4" x 2f* = 11-9 „ J cubic feet.
There ifl therefore an Fig. 10.

actual saving in this
instance, if purlins are
used in addition to the
practical advantage of
smaller timbers being
required.

41. An economi-
cal but unsightly ar-
rangement is shown
in Figs. 10, 11, & 12.
The trusses may
be spaced from 6 to
12 feet apart accord-
ing to circumstances,
and are intended to
carry purlins b, b}
which support the
common rafters a, a.
The arrangement
in Fig. 10 was suggested to the writer by an officer who has left the
country.

VOL. V. — SECOND SERIES. 2 ▲

Fig. 12.

TIMBERING OF PKMT BOON.

The part of the trass projecting above the roof is intended to carry a
ventilator. Figs. 1 1 and 12 are obvious modifications of the principle.

Not a A.

Stresses on the members of a wooden Ring Post Truss when the load is
uniformly distributed on the principals, Figs. 14 and 16, Plate XX1L At
any point in the principal, w may bo decomposed into w cos 0 acting si
right angles to the principal, and iv sin 0 acting parallel thereto. AY
being a continuous beam, the distribution of W = wh is as follows— on
either principal.

At V, ^ W cos 0.

B, {% W cos 0 + } W sin 0.

A, f£ W cos 0 + £ W sin 0.

Total resultant, ( * ~ ! * If? "*'? !° ?"***'

(, W 6in 0 parallel to principal,

equivalent when combined to W (in a vertical direction).

The distribution of the normal wind pressure at the trussed points is

similarly

•t v, a w,

n B', tf W,

.. A', A W'f
and the resultants are

at A', R" = W'B!j?,

„ A', R' = W'-R'.
As an example (see Plats XXII.), diagrams have been constructed of
two king post trusses, L = 10 feet, pitches 80° and 60°, to = uf = 40
x 5 = 200, W = W = 2,000,
w = 150, w* = 250, W cos 80° = W sin 60° = 1,782.

W sin 80° = W cos 60° = 1,000.

Load.

Talm.

Beta*
enoeto
flgnn.

•0°.

ft*

SOP.

ft*

Dtnotton.

Load at A", ..

W oos0

«v

825

188

± A*V.

Thrnst at M

W sin*

a'f

500

866

1 .

Iioad n B*f

W cosO

vpr

1,082

624

-L »

Throat n „

•

W sin0

500

866

1 -

TIMBIBIRQ OF PIMT ROOM.

179

Load.

Veins.

Refer*
enoefeo
flgnre.

80°.
lbs.

•0°.
lbs.

Direction*

Loads at V,

,\ w cose

c*r

825

188

± A' V.

n n n ••

150

Vertical.

#t n •# ••

r aw cose

I av

700

568

± AT

Thnut M B p. • •

1 W sine

e'/3'

500

866

1 ,.

Loads „ B,

i if w cose

[/8»'

2,882

1,874

± »

Thrust n A\ ..

A W sine

•V

500

866

1 H

Loads „ A', ..

J y3¥ W cosO

t+fV w

700

663

± ..

Reaction at A', ..

|W+i±^

2,200

Vertical.

1 W - R*

Am*

1,883

nil

JL AV

Load „ M, ..

mm'

250

Vertical.

Reactions „ A*,..

«t'A'

667

2,000

X AT

n n n ••

w+ a

2,200

VerticaL

The following trigonometrical expressions for the maximum stresses on
the principal members of the truss have been deduced from the diagrams
Figs. 13 and 15 in the Plate. The expressions are complicated, and it
will in general be found less troublesome to construct a diagram than
to work them out.

From 0 = 0° to 0 = 38° 20'. T =b'p' —

i'. T =b'p' — ]

to cosece /- . 5cos*0x w + W* a , ttt, cot0/ol • n\ ( (W).

W — J- (1 + -g— )+ —j— cosecO + W -j-(Sf -sec*a;» j

From 0 = 88° 20' to 0 = 90'. T" = Vp" =

cosece

5cos*e<

(i + •-sp) +

w + w'

cosece

. mi sec e cosec e > (15a).
+ W . I *

2 V" ' 8 / ' 2

Equation (15) gives the thrust at A, from which point it decreases

uniformly along AB to B, where its value below the purlin is = T — •&

= T - i W sin 0

174

TIMBERING OF PEST BOOF9.

At the centre of the lower section of principal,

the thrust = T' or T" - J W sin 0, (155).

H' = pW = W yg!S + !L+ZlCot6+W'^ (2l- tan*0,)(15c).

S' =pY = ?^25fL? (W + W sec 6), (15(f).

K = 9y =

16
5cosec0

(W + W ^) + w«,

(15«).

Note B.

The stresses on the members of a simple symmetrical truss, when the
load is uniformly distributed, may be obtained in a similar manner, see
diagram, Figs. 17 and 18. The distribution of the permanent load is as
follows on either principal,

at V, i W cos 0,

„ A, £ W cos 6 + W sin 0,
and the distribution of the normal wind pressure on VA' is £ W at V and
A', the resultants remaining as before.

Taking the same example, but putting w = 400, we hare,

Load,

Value.

Refer-
ence to
figure

80°.
lb*.

Direction.

Load at A*, . .

4 W cos 0

a'a"

866

J_A'V.

Thrust at „

W sin 0

a'b'

1,000

1 n

Load f, V,

4 W cos 0

866

JL n

tt n tf ••

400

VertictL

n n n ••

4 W cos 0|
4 W J

fib'

866)
1,000)

J.VA'.

Thrust „ A',

W sin 0

1,000

1 n

Load „„

4 W cos 0 1

8661

n mm ••

4 W )

a'a'

1,000 )

± »

Reaction at A', . .

W + 4 w

a'A'

2,200

Vertical.

n n n ••

W - R#

1,838

JL.VA'.

m n A , ..

R' W "^ *

»A'

667

it n

» m n ••

W + 4 w

2,200

Vertical

TIMBERING OF PENT ROOM. 175

The following expressions for the several stresses may be deduced
from the diagram, Fig. 17.

T = b'p = \ W cos 0cot e + i w cosec 0 + ± W cot 0 (2 - sec2 6), (16).
T'sr^p = £ W cos 0 cot 0 + £ w cosec 0 + J W sec 0 cosec 0, (16a).
T* is always greater than T'.

T = thrust at A, from which point it uniformly decreases to T — ab
= T — W sin 0 at V.

Thnist at centre of A!Y=Tm = ±W~£ + J w cosec 0 + ± W'cot0 (2 - sec»0), (166).
H = £ W cot 0 + i W cosec 6(1- tan» 0) + £ w cot 0,...(16c).

Note C.

The expression given in the former article* (Eq. 7B,) for the most

economical arrangement of the beams of a flat roof, omits consideration

of the ends of the beams resting on the side walls, and assumes that the

fcpace to be roofed is infinitely long. This is not strictly accurate, but

the difference is not important, the table, page 563,* may be accepted ;

if a small addition is made to the tabular numbers.

Calling the lengths of beam resting on walls a, and the total lengths
of the beam = L + a, Equation 7B becomes,

B = 0-557 L* (L + a)*. (£)* . (-1) (17),

or i close approximation to S may be obtained by multiplying the tabular
numbers by 1 + ^-.

To allow for the end walls, call total length of the room /, and the
number of bays in the roof n, then the number of beams = n — 1, and

tiie central spacing of the beams = I -r n = In'1,

Abo we have the cost of any beam, the scantling of which has been
fixed by the deflection formula, equal to

144

. v (L + a)

= cvr~ vr L* (L + a), where c = /=- -f- 144.
We hare then the cost of all the beams in the roof

•Ho. LTU., Pi^«rion^PapmooXadiwBBciiiMrlBfftCB«oeiidS«lM.]

TIMBERING OF I'KNT BOOFS. 177

,= i' ?

if we increace / without limit, -=- and -y ultimately vanish, and

which is Eq. 17a.
If we put o = 0,

this becomes i = -r= . f-^J . (— ) , which is Eq. 7B. of the former

Article.

Approximate values of* = /-fn from Eq. (17a). R = 2, r = 1*5,
V = Rs. 2-8-0, v = Rs. 2-0-0, a = 3.

Length.

Span 16 feet.

Span 20 feet,

6paa tt feet

16 feet

780
(2 bays).

•••

20 feet

7 02
(8 bays).

838
(2 or 8 bays).

•••

25 feet

682
(4 bays).

809
(8 bays).

9 65
(8 bays).

86 feet

6-58
(6 bays).

7-78
(5 bays).

9-22
(4 bays).

40 feet

652
(7 bays).

7 69
(5 bays).

911
(4 or 5 bays).

Infinite.

5 67

6-42

7-68

W . H. M.

178 WORK AND WAGES.

No. CXCIL

WORK AND WAGES.*

A Review by an Executive Engineer.

This book is written by the son of the celebrated Engineer Contractor,
from materials collected by the father, and augmented by the industry and
observation of the son. It is dedicated to the author of " Tom Brown's
School Days," and is prefaced by a few observations of the lato Sir Ar-
thur Helps who testifies to its importance. It is a 6mall pocket volume
of 284 pages of large type, and costs only a few shillings. But its value
is priceless. To the formation of a theory of industrial law worthy the
name of science it furnishes a contribution of extraordinary value. It
was first published in 1872, had reached its 5,000 in the following year,
and \ias since gone through several editions. It not only records the
precious experience of a long busy and unique life, but is a rich store
house of valuable data collected from many reliable sources and brought
together in methodical order. The immense range of the late Mr. Bras-
sey's dealings will be appreciated by the simple statement, that he expend-
ed over the four quarters of the world on his own contracts no less than
seventy-eight millions sterling, or an eighth part of the present capital of
all the English Railways. In fact such a field for investigation in indus-
trial philosophy has never before been offered to the world in so compen-
dious a form. The volume thus contains ample food for thought, and is
eminently suggestive. More especially is there much in it to interest
Indian Engineers, whose vast and varied sphere of labor is replete with

• On Work and Wag**, bJ Thomaa Braawy, M.P., Ball and Daldy, 1678. Prica 7*. 64.

WORK AND WAGES. 179

numerous social problems of the most intricate and obscure kind. It is
proposed to review it at some length in these pages, with the hope that
Indian Engineers may be able to furnish information of a similar kind.

Mr. Brassey divides the subject into several convenient heads, some
only of which can be here considered. In every case he illustrates the
subject by numerous practical examples culled from many sources. Of
these we have only room to record the most striking. The heads under
which the whole subject can be most conveniently reviewed are—
I. Demand and supply.

II. Dear labor stimulates invention.

IIL Bates of work not in proportion to rates of wages.

IV. Hours of labor.
V. Wages, their rise and fluctuations.

VI. The industrial capabilities of different nations compared, and
VII. Piece work.

The recognition of the rights of free labor came late in the history of
the world. To the Greeks and Romans it was unknown. For ten cen-
turies after the third the church was its best protector. For the next five
centuries the Parliaments, the Legists, and the Lawyers did much to se-
cure its liberty. Subsequently the mighty force of public opinion removed
one by one the working man's fetters, until we reach the almost perfect
freedom of the present day. Nor is this all. The laborer by uniting with
his fellows endeavoured to quicken the ameliorating process. And this
is not a thing only of the present time. " The guilds of the middle ages
were but the forerunners of the Trades Unions of to-day, and the strikes of
modern times have had their counterpart in the Jacquerie riots of the four-
teenth century." But the potency of Trades Unions has, Mr. Brassey con-
siders, been greatly exaggerated. Nine hundred thousand men are em-
ployed in the building trades of England : not more than one-tenth of these
are members of Trades Unions. And so little has this small proportion
been able to effect in equalizing their wages, that the wages of masons,
bricklayers and carpenters, each vary from 4}d. to 8|ri. per hour. Or to
give another instance : after protracted struggles in various trades against
reduced wages at Preston and at Wigan in 1852, 1853, 1865 and 1868,
the workmen were compelled in every case to accept the original pro-
posal of their employers.* Though Mr. Brassey plainly points out

" "Tbeiaooen which marked Mr. Braawy's career has become matter of notoriety; tratnoem-
VOL. V. — SECOND 8BB1B8. 2 B

180 WORK AND WAGES.

the harm wrought by Trades Unions, he at the same time shows the good
thej have done, and are capable of doing when confining themselves to
their legitimate spheres of operation. Bat, for them India is not yet ripe.
" When in any country," says Adam Smith," the demand for those who
" live by wages is continually increasing, the workmen have no occasion
" to combine to raise their wages. The demand increases necessarily with
" the increase of the revenue and stock of every country, and cannot possi-
" bly increase without it. The condition of the laboring poor and of the
" great body of the people is healthy in a stationary, and miserable in t
11 declining, state. The progressive state is in reality the cheerful, and the
41 hearty state in all the different orders of society. The stationary is
" dull, the declining melancholy." These axioms of the great economist
are abundantly verified by the facts adduced by Mr. Brassey, some of which
are well worthy of being here recorded under

/. Demand and Supply. — When the Grand Trunk Railway was being
constructed in Canada, the late Mr. Brassey sent out a great number of ope-
ratives from England. On landing in Canada, they received for doing the
same work 40 per cent* more than they had been earning, although the
cost of living in Canada was not greater than in England. The obvious
cause of this was, that the supply of such labor was abundant at Home,
while in Canada skilled artizans were comparatively rare. The fall is
Wages which follows a commercial panic, when production is diminished
and employment is scarce, proves how closely the rate of wages fluctuates
with the varying relations between demand and supply. When the Eng-
lish railway panic took place in 1847-48, even the common laborers em-
ployed on the Eastern Union Railway accepted lower wages. In 1849,
men who on the North Staffordshire line shortly before the panic had been
paid 3*.6c2. a day, only earned half a crown on the Royston and Hitchin
Kne.

The following table gives the weekly wages earned by men employed on
railway works from 1848 to 1869.

••pi oyer ever dealt more liberally with labor. The almost invariable remxlt of the oommenotntot
M of Railway operations in any country in England, or in any country abroad, was a rise in the pre*
" Talent rate of wages. On one occasion an estimate was submitted to him for a contract, for whies
"a sharp competition was expected. The prices had accordingly been out down to an unusually to»
" figure. He thereupon asked ' How it was proposed to carry on the work for such insdeqcaM
M prices ' ? In reply it was stated that the calculation was based on the assumption that a wdocttos
" ol wages could be negotiated. On receiving this explanation, he desisted from all farther exsnms-
" tlon of th» estimate, saying that if business could only be obtained by screwing down wages, b*
" would rather be without It," pages 8 and 9.

WOKK AND WAGES.

181

Periods.

1848

ISM

1849 1SS1

1SU

ISM

18S0

1868

1SS6

1869

«.

Masons, •• •• ••

21/-

83/-

24/-

21/-

25/6

24/-

22/6

24/.

27/-

Bricklayer*,

21/-

80/-

24/-

21/-

2f./6

22/6

24/-

27/-

26/8

Carpenters and Blacksmiths, ..

21/-

30/-

22/6

21/-

24/-

22/6

24/-

256

24/-

Navvies, Getters (Pickmen), • .

16/6

24/-

18/-

15/-

•

19/-

18-

17/-

19/-

20/-

18/-

„ Fitters (Shovellers), . .

15/-

22/6

16/6

14/-

17/-

•

17/-

16/-

17/-

18/-

1T/.

Cost of labor only per cubic yard.

■

Of Brickwork, • • . •

2/8

8/9

2/9| 2/8

2/6

214

2/6

2/9

2/8

Of Earthwork,

-/«

-/7|

./5l -/4

•Ml

./5J

•/6

-M

-/5|

The Mowing note on the railway furore by one of Mr. Brassey's cor-
respondents will be interesting.

" Lancaster and Carlisle, Caledonian, Trent Valley, North Staffordshire, Eastern
u Union Hallways in construction. Height of the railway mania* Demand for labor
" excessive, very much in excess of supply. Beer given to men as well as wages.
" Look outs placed on the roads to intercept men tramping, and take them to the
M nearest beer shop to be treated and induced to start work. Very amok less work
« done in the same time by the same power. Work going on flight and day, even
M the same men working continuously foy several days and nights. Instances re-

• corded of men being paid 47 days in one lunar month. Provisions dear. Bx-
" cessively high wages, excessive work, excessive drinking, and indifferent lodgings

* caused great demoralisation."

The activity of the Welsh Iron Manufacture of the present day is
remarkable.

The following table shows the comparative earnings of the workmen
in the years 1842, 1851 and 1869.

Comparative earnings of Workpeople employed in Iron Manufacture.

1849.

WM.

1869.

OooipalttB«

Price
per tea. .

Wages

per weak.

Price
per ton.

Wages
! P- week.

Price per
son.

Wages per

Miners, •• ••

• •

W/-toW/-

• •

Il/-tol6/-

• •

a.
12/- to 16/-

Colliers, •■• ••

• •

14/4ol«/-

• •

16,-tol8/-

• •

16/- to 20/«

Furnaces,

Founders, • • • •

*/-/-

17/-tol8/-

8/-

25-to29/-

i/A

27/- to 80/-

Fillers, • •

• •

17/-told/-

8>'-

25/-to29/J

i/A

27/- to 80/.

182

WORK AMD WAGES.

1842.

1851.

1869.

Occupation

Price
per ton.

Wages
per week.

Price
per ton.

Wages
per week*

Prioeper
ton.

Wages per
week.

£ 9.

«.

£ #.

«.

Cinder fill, ••

8/6

15J-tol6/-

■»

21/-to24/-

V!t

20/-to22J6

Laborers, ••

• •

10/6

• •

10/6

»«

ll/6tol2/6.

Forge, •• •• J
Puddlera, .. j

Pig-iron

nil,

metal 106/-

1st hand

Share
16/tol6/6
21J-to22/-

Pig-iron

90/-
metalnil
1st hand

Share
16/-tol8'-
22/-to25/-

4/11, 5/U
and 4/-
1st hand

18/-to24/-
28/-to32j-

Laborers, ••

• •

10/6

• •

10/6

».

10/6tol3/-

Girls, ..

• •

4/9

• •

5/6to6/6

Mills:

Bar -iron

• •

Rails

• •

Bails

• •

Heaters, • • • •

1/6

24/-to26/-

First

heater 1/1

second

heater

-/6*

26/-to27|-
36/-to37/-

First
heater-/10|
second
heater- 5 J

25/-to28!6
85/-to40/-

Boilers, &&, ••

1/8J
contract

• •

10/8

• •

Roller^/-

Rangher

40/-each.

Laborers, •• ••

• •

10/6

• •

10/6

• •

;il/-tol2/6

Girls, .. ..

• •

4/9

• •

4/9

• •

5/6 to 8/-

Carpenters, ,.

• •

12/6

• •

18/-tol4/-

• •

18/-tol6/6

Patternmakers,

• •

13/-tx>14/-

• •

13/-

• •

13/6tol9(-

Fitters, .. ..

• •

12/-tol4/-

• •

12/-toH/-

• •

13/-tol9/-

Blacksmiths, ••

• •

12/-tol5/6

• •

contracts

••

14/-to22/6

Masons, .. ..

• •

12/-tol5/-

• •

15/-

• •

14/- to 20/.

Let us now take an instance or two from Foreign countries. At Loben
in Silesia, the erection of a factory in an agricultural district caused a
rise in laborers wages (which were only 6tf. a day for men and 3d. for
women) of 50 per cent, for the former, and 100 per cent for the latter.
Owing to the limited supply of skilled labor the wages of artisans in all
newly settled countries are higher than the rate in England. A fitter
whose annual salary in England would be £78, commands £200 a year at
Rosario in the Argentine Republic. Engineers of steamers on the Ri?er
Plate, are paid ,£240 a year, or more than double the rate they would ob-
tain in England.

The following observations of Mr. Brassey are of great interest to In-
dian Engineers :—

WORK AND WAGES. 183

Since 1858 we hare subscribed no less than 40 millions of pounds for Indian
Railways. A considerable portion of this sum has been paid to native laborers, and
the result has been that in the districts traversed by these railways, wages have
advanced within a short time no less than 100 per cent In consequence of the
great demand for workmen, the price of labor has increased to an extent still
more marvellous in Bombay.

Wages in that Presidency are now two or three times higher than In Bengal and
the Punjab.

In a paper furnished to the Select Committee on East India Finance by Sir Bartle
Frere, some remarkable examples are given of a rise in wages in consequence of the
increased competition for labor for railways and other great public works.

The following table shows the variations in the average monthly wages of a car-
penter in Bombay : —

8. d,

1830-89 80 4

1840-49, 28 10

1850-59, 82 74

1868, 58 0

The following table shows the wages of a coolie at the same periods : —

t. <L

1830-89, 14 9|

1840-49, 12 3f

1850-59, 14 2

1868, 27 0

Everywhere in the vicinity of railway works the Collectors remark on their great
effect in raising wages. The practice of promptly paying for all labor in liberal
money wages caused an important social revolution in the habits of all who live by
labor, even at a great distance from the railway works. The laborers often travelled
from their homes 200 miles to obtain work so paid, returning home at the harvest time.

The increase in wages in Bombay had increased the number of consumers of supe-
rior qualities of grain and meat. The increased consumption had raised the cost
of living. The advance in the cost of living had had the effect of raising the rate of
wages : for with their former earnings the people could no longer have provided
themselves with the necessaries of life.

Moreover, the increased external trade of Bombay, the influx of money for the
purchase of commodities, and the consequent depreciation in the purchasing power of
bullion, and the increased demand for labor, had by their combined influence pro-
duced an astonishing advance of wages in Bombay, as compared with Bengal

The following table shows the difference between the rates in Bengal and Bombay : —

In Bengal In Bombay

per month. per month.
Ra. Bs.

Carpenters, •• •• •• 9 •• •• 25

Masons, 5^ •• . . 21

Laboring coolies, •• •• 6 . . 9|f

Hone keepers,. 5 •• •• 8^

It is impossible to produce a more striking example of the effect of an increased
cost of living, and an increased demand for labor in raising the rate of wages.

In pointing out the intimate relations which exist between capital and
labor Mr. Brassey forcibly remarks : " Pernicious in their social tendency

184 WORK AMD WAOB8.

and scientifically inaccurate are the doctrines of those who seek to persuade

the working people that the capitalists are their natural enemies." And

he gives a striking though melancholy instance :

At the head of the Golf of Bothnia, far removed from the enjoyments and advan-
tages of European civilization, there dwells a commonity of peasant!, on whose dreary
abode for a considerable part of the year the son never shines. In frost and snow
and darkness throughout their long winter, these unfortunate people are engaged in
felling and sawing timber and making tar. When the spring at length returns, and
the. seas so long frozen up are once more navigable, a few mercantile agents pay
them an annual visit and purchase the timber and the tar which have been prepared
in the previous winter. The purchase is effected not by giving money in exchange,
but by a system of barter, in which the peasants, innocent of the value of their own
labor, are hardly dealt with. They receive a supply of meal barely sufficient to mam-
tain them during the coming winter, and a limited quantity of cutoff clothing, pur-
chased perhaps from the old clothes dealers of London. Many of these poor people
have never tasted meat, and as they are always in debt to the merchants for the sup-
plies of meal which they have accepted in advance, they are not in a position to nego-
tiate, as independent parties to the transaction, for more liberal terms of payment
During the summer the people work for a great many hours ; but from imperfect
nourishment their physical strength does not enable them to put forth the same exer-
tions as an English workman.

" To what, " says Mr. Brassey, " shall we mainly attribute their pitiable
" condition ? To the entire absence of accumulated capital, and the depen-
" dance of the peasantry on employers who are too poor to be generous, and
" in whom the desire to make the most of their small capital has altogether
" extinguished the virtue of charity and the spirit of justice."

Numerous similar illustrations are afforded in India. Even now there
are many parts where the plight of the inhabitants is as pitiable as that
of the peasants in the Gulf of Bothnia. The condition of others has been
improved by the influx of capital supplied both by Government and by
private individuals. Not many years ago in a certain delta the villagers
were so poor that the women had to remain in puria naturalibus, and
could never leave their miserable homes except during the hours of dark-
ness. Large sums of money were subsequently poured into the District
to create irrigation works, and completely changed the condition of the
residents. Note similar facts in Hunter's " Orissa" and "Rural Ben-
gal." Observe also such parts of India into which European enterprise
and capital have entered in the shape of Planters— owners of tea, coffee,
and indigo estates. There on each estate, £1,000 are commonly paid
away monthly in wages to the coolies. The improvement thus effected in
their condition is clearly perceived by those who work in their districts,

WORK AHD WAGftS.

185

and the advantage to the laborers in every way by this arrangement is
obvious. The policy of statesmen in the interests of the Natives alone
is clearly to encourage such European " interlopers. " Yet how frequent-
ly are they obstructed through an erroneous and short sighted policy.
The example of these Europeans has already communicated itself to the
Natives. In some parts the latter have amassed money with which they
have purchased virgin land, and have opened and planted it with indigo,
coffee, and tea. The Government land sales in many hill districts are as
keenly competed for by Natives as by Europeans. The spread of thia
spirit amongst our Arian brethren is greatly to be desired.

II. Dear labor stimulates invention.— It used to be thought that the
substitution of machinery for hand labor, and the consequent diminution
in the number of hands employed, was a change prejudicial to the interests
of labor. But M. Michel Chevalier truly says, that machinery can alone
enable dear to compete with cheap labor, and that England, which makes
57 per cent, of the textile fabrics of Europe, owes her superiority entirely
to the extensive use of machinery.

The following table shows how machinery augments the productive
powers as well as the earnings of the operatives r —

Work turned off
by one spinner
par week.

Hot.

Wages per vnl

OroK.

Pieces.

Nett

Hoars

of work

per

races troin
Greenwich Hob*
pits! records.

Floor,
per

Flesh,
per ft.

Quantities which
a week's nett earn-
ing would purchase.

of
Soar.

lbs.
of flesh.

1804
1814
1888

180

60/-

27/6

82/6

83/-

6/-to7/-

117

200

67/6

81/-

86/6

88/-

6/-to7/-

124

180

72/-

27/6

44/6

70/6

8/-

175

13}

200

90/-

80/-

60/-

70/6

8/-

289

22}

180

54/8

21/-

88/8

457-

6/-

210

200

65/8

•

22/6

42/9

45/-

6/-

267

62}

In England, by the introduction of the locomotive, it is practicable to
carry a load of earth to a greater distance for the same money. In the
strike of 1851, Mr. Nasmyth by mechanical contrivances reduced the 1,500

186 WOBK AND WAGBS.

men in his employ by one-half, and very much increased his profits. In
Denmark, an improved system of working reduced the cost of railway
construction by 85 per cent. At the present time in Australia, though
the rate paid for labor is 20 per cent, higher, railways are made much
cheaper than formerly, owing to greater skill in construction, and from
machinery being employed to do work formerly directly performed by
men and horses. It wonld be very interesting to know the details by
which this economy has been effected : Mr. Brassey does not give them.
In America, wages are so high that cast is extensively used for wrought-
iron. To such a perfection has its manufacture been brought, that the
American cast-iron wheels withstand the great shocks to which they are
subjected by the imperfectly laid railroad, exposed as it is to peculiar
climatic inOuences, better than wrought-iron wheels procured from Eng-
land. Even rain water pipes are so beautifully cast that they are only £
of an inch thick, whereas in England they would be f of an inch thick.
In the hardware trade of the United States the wages of the workmen
are the double of those in England: but labor saving appliances have
enabled the United States to export hardware goods largely into countries
in which the pay of the artizans is only a quarter of the wage paid in
America. They send their spades, shovels, axes, coopers tools and pumps
to England, although their raw material and wages are twice as dear.

Returning to England, we may note two remarkable facts. The re-
manufacture of iron rails in 1860 cost £7 15s. per ton : in 8 years by
improvements in the machinery the price was reduced to £7, or by 10 per
cent., although in both cases the old rails were charged at the same rate.
And though wages have remained in statu quo, locomotives cost 7\ per
cent, less than they used to do, owing to the application of improved
machinery.

In India is not our experience altogether different? The use of
machinery seldom seems to answer. The machine whatever it is must be
simple, almost self-workable, and little liable to get out of order. It needs
close and good European supervision. Natives seem to have no genius
for it. They never come to love the machine as an European mechanic
does. The keeping of it in constant order and cleanliness never strikes
them as being essential to its economical and effective working. Work
turned out by machinery is thus generally more expensive than that pro-
duced in the ordinary native way. Even on such a simple thing ft* ft

WORK AKD WAGES. 187

pomp, how soon it gets out of order in a native's hands. Bat in the
matter of tools the results are more favorable. For example native car-
pentry is greatly improved and expedited by good and suitable tools.
Bricks are more quickly and better laid where the workmen are supplied
with proper implements. Mortar is better ground and mixed when certain
simple mills are employed. But in the use of complicated machinery,
where the intelligence of the native mechanic forms an integral part of
the performance, the result is generally unsatisfactory. Babbage has at
great length clearly shown that in order to succeed in a manufacture it is
necessary not merely to possess good machinery, but that the domestic
economy of the factory should be most carefully regulated.*

It will be apposite here to quote from the Pioneer some remarks made
by two competent authorities on the relative advantage of employing saw
machinery in converting timber into scantlings. They were made on a
paper read before the recent Forest Conference at Simla. Mr. Guilford L.
Moles worth, Consulting Engineer for (State) Railways— compared machin-
ery with hand work, and showed that the financial success of the former
was not so great as was generally supposed, instancing brickmaking as an
example. Passing on to saw machinery, he compared circular with up-
right saws. It was probable he said that in the future the hand saw would
be need for the conversion of large timber, though it was not yet sufficiently
perfected for that purpose. In forests where skilled labor was hard
to obtain, it would be difficult to introduce what would be theoretically
the more perfect machine for working. Dr. Brandis remarked that there
were two essential conditions for the success of machinery, firsts that the
forest must contain mature timber in compact masses ; and secondly, that
hand labor must be uncertain or very expensive : under these conditions
saw machinery became a necessity.

///. Rates of Work not in proportion to rates of Wages. — Mr. Joseph
Hume in 1 825 thus spoke in the House of Commons. " He had heard .
" it stated that low wages were a good thing. This he denied. Low wages
" tended to degrade the laborer. It was the high wages which the Eng-
lish artizan received, compared with the miserable pay of the Irish
" laborer, which made the former so superior in energy. " And Mr.
Fawcett observes that, " the cost of labor is determined by the amount of
" work which is really done for the wages. Many of our laborers can

• Economy of Manufacture*, by C. Babbage, 183 J, page 296.
VOL. T. — SECOHD SERIES. 2 0

1S8 WORK AMD WAOK8.

44 barely obtain the necessaries of life, and we can all appreciate the fake
41 economy which would be practiced if a hone was so much stinted in
44 food that he could only do half as much work as he would be able to
41 perform if lie were properly fed."

But Mr. Brassey goes further. He maintains that daily wages are no
criterion %of the actual cost of executing works or of carrying out manu-
facturing operations. On the contrary, he proves by numerous examples,
that there is a most remarkable tendency to equality in the actual cost of
work throughout the world, and that it is quite possible for work to be
executed more cheaply by the same workmen notwithstanding that their
wages hare largely increased. " On my father's extensive contracts," Mr.
Brassey asserts, " carried on in almost every country of tyie civilised world
41 and in every quarter of the globe, the daily wages of the laborer wia
44 fixed at widely different rates, but it was found to be the almost invari-
" able rule that the cost of the work carried out was the same — that for
41 the same sum of money the same amount of work was everywhere per-
44 formed."

The ipsmima verba have been purposely quoted, for this is a startling
statement which can only be accepted in its broad sense. Exceptions will
arise to prove the rule. But Mr. Brassey proceeds to clothe the bare
announcement with all the reality of ascertained facts. When the North
Devon Railway was begun, the wage of the laborers was 2 shillings a dsy.
During the progress of the work it was raised to 3 shillings. Nevertheless
the work was executed more cheaply in the latter than in the former period.
In carrying out apart of the Metropolitan Drainage in Oxford Street, the
wages of the bricklayers gradually rose from 6 to 10 shillings a day;
yet the brickwork was constructed at a cheaper rate per cubic yard after
the wages of the workmen had been raised. During the construction of
the Refreshment Room at Basingstoke, on one side of the station, a London
bricklayer was employed on 5s. 6d. a day, and on the other, two country
bricklayers each at 3s. 6<J. It was found by measurement, made without
the knowledge of the men employed, that the one London bricklayer laid
without undue exertion more bricks than his two less skillful country
fellow laborers.

In 1837 the condition of the inhabitants of the Western part of Ire-
land was deplorable. Their food consisted of potatoes without meal or
milk. The cabins were wretched hovels, the beds were of straw, and

WORK AND WAGES. 189

the laborers wages were only Sd. a day. The usual results followed.
Poverty and misery deprived them of all energy. Agriculture waa at its
lowest. The produce of the soil per acre was only one-half the average
in England, whilst the number of laborers employed on the same area in
Ireland and England was as 5 to 2. During the construction of the Paris
and Rouen Railway, there were at one time 500 Englishmen in the village
of Rollebois, most of whom were employed in the adjacent tunnel A1-*
though these English navvies earned 5 shillings a day, while the Frenchmen,
employed received only half a crown, yet two adjacent cuttings under pre-
cisely similar circumstances cost less per cubic yard with the English
navvies than with the French laborers. x The mileage cost of the Delhi
and Amritsar Railway has been found to be about the same as a similar line
in England, although the daily wages on the Delhi line were marvellously
low. Earthwork is executed by the coolies at a cheaper rate than in
England, but native skilled labor is more expensive.

" The execution of the works on a nil way in India," says1 Mr. Braasey," is general"
ly undertaken by small contractors or middle men, who in many cases are shopkeepers.
There is a difficulty in obtaining experienced sub-contractors, and, in consequence, it
is necessary to employ a numerous body of English foremen. Hence the cost of
supervision is greatly enhanced in India, and is found to amount on the average to 20
per cent, on the entire outlay. Before the railways caused an increased demand for-
labor, wages ranged from id. to i\d. a day. The demand for labor raised wages con-
siderably, but even then the coolies were not paid more than Qd. a day. However,
these wages far more than sufficed to supply all their wants. Their food consists of
3 lbs. of riee a day mixed with a little curry ; and the cost of living on this their usual
diet is only 1*. a week. For 1*. 6d. they can live in comparative luxury. On the
railways of India, it has been found that the great increase of pay which has taken
place has neither augmented the rapidity of execution nor added to the comfort of
the laborer. The Hindoo workman knows no other want than his daily portion of
rice, and the torrid climate renders watertight habitations and ample clothing alike
unnecessary. The laborer, therefore, desists from work as soon as he has provided for
the necessities of the day. Higher pay adds nothing to his comforts ; it serves but
to diminish his ordinary industry.*

After a review of work done in France, Italy, Austria, Switzerland,
Spain, Germany, Belgium and Holland, Mr. Brassey makes this remark-
able statement : — " The wages paid in England are higher than in any
"other country. Yet even with respect to bridges, viaducts, tunnels,

• - It Is not," says If cCullooh, M in the best situated countries or those of which the ollmate li the-
finest, and the soil most productive, that the peasantry are the beet off. In those their necessities are
few and easily supplied, and when they are satisfied they seem to care for nothing more.14 Hum-
boldt tells us that it had been proposed to prohibit the culture of the banana in Mexico as being the
only means calculated to rouse the torpid qualities of the natiTes and make them in some degree in-
dustrious-- page 9a.

190 WORK AND WAGES.

" and all works of art on railways, they can be executed at a cheaper rats
" in England than in any other country in the world. The rate of wages
" is much lower but masonry costs as much in Italy as in Manchester."

To those who have to employ convict labor it will be interesting to learn
that the Prussian Councillor of State, Jacobi, is considered to hare proved
that in Russia, where everything is cheap, the labor of the serf is doubly
as expensive as that of the laborer in England. In Austria the labor of
a serf is one-third that of a free hired laborer. Slave labor was once em-
ployed on the Drainage Works at Rio Janiero. But free Portuguese
labor even at 4*. 6d. a day was infinitely cheaper. 80 slaves on an estate
in Pernambuco produce 171} tons of sugar. Their annual cost of main-
tenance and replacement was £765. Their first cost was £4,050, interest
on which at 12 per cent, was £486. This gives a total of £1,251, which
was expended in producing 17 1£ tons of sugar, at £7*8 per ton. The
wage of the free negro laborer without food was lCfri. per diem. Allow-
ing that the number of free laborers equalled that of the slaves, though
it was generally admitted they worked harder, the total cost would amount
to £1,080 or £6*3 per ton. The free native laborer is thus but little
above the level of the slave. His work is more effective by only one day
in the week, and it proved cheaper to engage the European laborer at
five times the rate of wages than to employ slaves.

The miserable pay of the women employed in the manufactories of
Russia suggests to Mr. Brassey some observations on the evils which ne-
cessarily arise from subjecting the female population to excessive manual
labor. These may be quoted as possessing great interest to Indian En-
gineers.

" In all the less civilized countries of Europe the women are compelled to share in
the manual labors of the men. This practice is in a large degree the cause of that
very poverty which it is intended to alleviate. The introduction of so many addi-
tional hands into the labor market has a marked effect in diminishing the reward of
labor. In Russia on the Lemberg and Czernowitz line half the people employed were
women. They earned 1 60 francs a day, and the men from 2 to 8 francs. On the
Bukovina line the wages of the men for picking were 1*. 6d. a day, while the women,
who worked only with the shovel, earned about 6d. a day less than the men. The
cost of living for a man, his wife, and three children in Hungary, may be stated ap-
proximately at It. a day. In those countries the cost of unskilled labor is small, bat
the struggle for life is so severe, that every child the moment it can add the smallest
fraction to the earnings of the family is sent into the fields. The infant mortality
in Russia is appalling. The peasant women give birth to their offspring under cir-
cumstances equally perilous to the life of both. Their confinement takes place in a

WORK AND WAGES. 191

bun or a stable. They hare no medical attendance, and in three days they are once
more employed in hard field labor. The result of each privation and suffering is, that
a large proportion of infants die within a week after their birth. The number of males
living at the age of 5 years in proportion to the total number of the population is 20|
per cent less in Russia than in Great Britain, France and Belgium. The shortness
of the average dnration of life is equally lamentable. In the North West Provinces,
the average limit of life is between 22 and 27. In the Volga Basin and South East-
ern Provinces it is 20 years. In Viatka, Perm and Orenburgh it is only 15 years.

IV. Hours of Labor. — We have seen that the mere rate of daily
wages affords no indication of the cost of the work. Mr. Brassey shows
that it is equally true that the hoars of labor are no criterion of the
amount of work performed. The Messieurs Dollfus of Mulhausen reduced
the daily working hours of their Establishment from 12 to 11, and pro-
mised the men that no reduction would be made in their wages if they
performed the same quantity of work. After a month's trial the men
did in 11 hours not only as much work, but 5 per cent, more than they
bad previously performed in 12. Miners work 12 hours a day in South
Wales, and only 7 in the North of England ; yet the cost of getting coals
in Aberdare is 25 per cent, more than in Northumberland. In Messrs.
Bansome and Sim's at Ipswich 1,200 artizans are employed. In
1872 their hours of work were reduced from 58£ to 54 per week : but
so strenuously did the men labor, that the power required to work the
tools was actually increased by 15 per cent. "The leisure which the
11 wealthy enjoy," says Mr. Brassey, " is their highest privilege. The
" want of opportunity for thought and cultivation is the greatest privation
" of those who are compelled to pass the greater part of their lives in
"manual or mental toil." The eloquent language of M. Jules Simon in
his essay on labor will doubtless be fully appreciated by the generally
overworked Indian official : " Gette condition parait assez dure. Ge n'est
pas a cause du travail, dont personne ne se plaint, ni a cause de la priva-
tion du superflu ; e'est parce que dans une vie ainsi faite il ne reste pas
de place pour l'ltude, pour la possession de soi-meme. Ce besoin d'£tudier
et de penser n'existe pas partout, meme en France. II faut pour l'eprou*
ver une certaine elevation de sentiment, autrefois rare, aujourd'hui presque
universelle, au moins dans les grands centres de population. A quoi tient
ce changement ? Au progres general, auz merveilles scientifiques accom-
plies chaque jour sous les yeux de la foule, a l'augmentation de bien-£tre
resultant de l'augmentation du nombre des produits manufactures, a une
instruction plus itendue et plus repandue, a 1'orgueU legitime inspire par

192

WORK AND WAQK8.

leg souvenirs de la Revolution et par la possession des droits politique*."
V. Wages, their rise and fluctuations. — In the Engineering Trade in
England there has been no appreciable augmentation since 1852 in the
wages earned by the operatives even in recent years. The following
Table (page 193) was obtained from the Canada Works at Birkenhead.
They were established in 1854. The average number of hands is 600.

" In England/' says Mr. Brassey, and it is an observation well worthy
of note by us in India, " wages would have risen to a far higher scale,
unless the enlightened policy of free trade had been adopted, and in-
proved communications by sea and land had given increased facilities for
the importation of cattle and other supplies from distant countries."
The following Table (page 194) of the prices of provisions in the rural dis-
tricts of Staffordshire will show how much has been accomplished by the
liberal fiscal policy of England in reducing the cost of the necessaries of life.
The well known builders, Messrs. Lucas and Brothers, state that for
some years prior to September 1853, the rate of wages was as follows :—

For Mechanic*, Xaaooa, Brick
layers, Carpenters and Plasterer*.

Previous to 1858,
From September 1853 to I
March 1861, . . f

March 1861 to Sept 1865,

Sept 1865 to May 1866,

May 1866 to present time,

5«. per day of 10 hours.
5#. Sd. per day of 10 hours.

Id. per hour, or 5#. 10<J. per

day.
l\d. per hour, or 6*. 3d. per

day.
$d. per hour, or 6*. Sd. per

day.

8*. per day of 10 hoars,
3#. 4 d, per day of 10 hours,

4Jd per hour, ox Si. 6}&per

day.
4$rf. per hour, or 8#. 9 A per

day.
4f(f. per hour, or 8a Hi*, per

day.

They consider that the price of building has increased 80 per cent, be-
tween 1858 and 1872. Turning to other countries, we find that in France
Belgium and Germany, the three chief competing countries with England,
the prices of food and consequently of labor are 80 per cent, dearer than
they were 20 years ago. In France 20 years ago laborers were content
to work for Is. 6(2. a day, now 2s. Ad. is the ordinary rate of pay. la
the famous establishment for building Engines at Greusot 10,000 persons
are now employed, and the annual expenditure in wages is £400,000.
Mechanics were paid when the establishment was first created 2} francs
a day ; now none receive less than 5 francs. Between 1850 and 1866
the mean rate of advance was 88 per cent. At the great Zinc Works,

WORK AWD WAGES.

193

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WORK AMD WAGES.

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WORK AHD WAGES. 195

known as the Vielle Montague near Liege, where 6,500 hands are employ-
ed, wages have increased 45 per cent, in 12 years. In Italy since 1861
wages hare risen in some trades 50 per cent. In Sicily and in lower
Silesia the pay of the working classes has doubled since I860.

VI. The industrial capabilities of different nations compared. — This is
an extremely interesting subject, but our space does not admit of our en-
larging upon it. We will merely record of few general facts, and insert
a rather long quotation relating to India. At the locomotive building
works in Belgium, the parts of the engines made from the same pattern
are seldom interchangeable: but this is always the case in England.
In all works in sheet iron the Belgians excel : but in wronght-iron
they are behind many other countries. A good lock and key is no where
to be found. A tolerable horse shoe is no where to be seen. And yet in
carriage building they have been eminently successful. The capabilities of
Englishmen are conspicuously shown in their superior skill as miners.
Mining is perhaps the most exhausting and laborious of all occupations.
h his been found that in this description of work the English miner
surpasses the foreigner all over the world. In point of manual skill, the
French and English are considered equal. In invention the Frenchman
may be the cleverer of the two : but in the power of throwing energy
into his labor, the Englishman is the better man. If a Frenchman has
a good model of a machine he will make it as well as an English mechanic,
bat the same number of English workmen will turn out four machines
wben an equal number of Frenchman will make only one. Great pains were
taken on the Paris and Rouen Railways to ascertain the relative industrial
capacity of the Englishman and Frenchman and it was found to be in the
ratio of 5 to 3. But as carpenters the French are superior to the Eng-
lish, both in the quality of their work, and in the price at which they do
it. " In original conception," says Mr. Brassey, " English manufac-
turer* do not perhaps possess any advantage over the manufacturers of
other countries ; but in the practical development and application of an
^vention, and in general administrative capacity, and especially in the art
of economical management, they have shown a real commercial genius,
^fcich is rarely exhibited abroad. " But in many continental markets the
English no longer enjoy the advantages which they formerly possessed,
foreign manufacturers, with their cheaper labor and more intimate know-
^4ge of the character and requirements of the people, are rapidly gaining
£"^oond. English iron masters compete with difficulty with the iron
vol. v. — sbcomd amiss, 2 d

196 WORK AMD WAGES.

works at Cologne, which supply many of the Russian Railways with
bridge*. In tyres we have to a great extent been driven oat by Krapp.
Of the large quantities of files now used in Russia, two-thirds come from
Germany. English saws on the contrary meet with an increasing sale,
their price having been reduced by one-half within the last few yean.
Imitations of English lathes are made in Germany for half the price,
and are largely imported into Russia.

In connection with Indian Railways the following information supplied
by Mr. Brassey may be quoted at length : —

" The experience of the Consulting Engineers of onr Indian Railways does not by
any means go to prove that foreign iron masters or engine builders can snccessf oil?
compete with the English. Their experience, it may be added, is all the more Tain-
able, because the Indian Railways afford the most perfect example of a purely neutral
market There is no personal influence acting on the minds cf Indian Railway Engin-
eers and Directors prejudicially to onr interests ; and no customs duties, which are
protective to onr manufacturers, are imposed upon the importation of onr manufac-
ture into India. The plant and machinery for the Indian Railways are purchased in
the cheapest markets ; and it is certain that the foreigner would be preferred regard*
less of national sympathies, if he could compete with the iron trade at home, either
in quality or price. Let us then examine into the actual state of the facts, as regards
the supply of rails and locomotives to the Indian Railways.

" I shall first appeal to the experience of Mr. A. M. RendeL In November and De-
cember 1865, tenders were invited by advertisement for a large number of locomotiTCS
for the East Indian Railway. Eminent foreign as well as English makers were free
to compete, and 22 tenders were sent in. The result was, that 80 engines, varying
in cost from £3,165 to £2,450, were ordered from English makers, at an average
price of £2,600 each ; 20 from Kiessler, of Esslingen, near Stuttgart, at £2,550
each ; and 20 from an English maker, at £2,440 ; so that the foreign maker received
a price intended to be intermediate between those of the English makers. It ought
to be mentioned that at the date when the order was given, English houses were full
of work. Not long afterwards, in consequence of the rapid development of traffic
on the East Indian Railway, it became a matter of urgent importance to send out
additional locomotives as early as possible. Accordingly 10 more engines wen
ordered from an English firm at the price agreed upon in the first tender, vix.,
£2,450 ; and 10 more were ordered from Esscher Weiss and Co. of Zurich, who
undertook to make them for £2,550 each, the price which had been previously accept-
ed by the other foreign makers. At the termination, however, of their contract,
Esscher Weiss and Co., made a representation to Mr. Rendel that they had sustained
a loss, and asked to be allowed, by way of compensation, to make 10 more engines
of the same kind, but at the enhanced price of £2,800. It is, therefore, evident
that in the results of their competition with the English makers, who were nnder
no pressure in regard to price, all the shops being so full of work that early deli-
very was an impossibility, Esscher Weiss and Co. had little cause for satisfac-
tion. Indeed, they admitted a substantial loss. But even if this contract had been
move satisfactory to Esscher Weiss and Ca than it actually proved, their socce*

WORK AND WAQ18. 197

would have been largely due to British industry ; seeing that the boiler-plates, the
copper fire-boxes, the wheels, the pig-iron for the cylinders, the tubes, and the
frame-plates (in short, two-thirds of the materials nsed in the construction of their
engines,) came from England in a manufactured state. It was the same with the
engines supplied by Kiessler. That firm assured Mr. Rendel that they could not
think of asking him to accept Prussian iron or copper, and that by far the greater
portion of their material came from England. Of course, to a certain extent, this
was done under the requirements of the specification ; but no pressure was needed on
the part of the engineers. The axles and the wheel tyres were specified to be of
Prussian steel ; but for this, they too would have been of English make. But the expe-
rience of Mr. Rendel is by no means limited to the purchase of locomotives. Bails
and iron bridge work upon the largest scale have been supplied in England for the
Indian Railways for which he has acted ; and the tenders have been obtained on all
occasions, when a large order has been given, by open advertisement ; and ail conti-
nental makers have been as free to tender and would be accepted on the same guaran-
tees as English makers. Tet out of the total expenditure during the last ten years, of
from £7,000,000 to £8,000,000 sterling on materials and plant for the East Indian
Railways constructed under Mr. Rendel's supervision, with the exceptions I have
made, the whole of these contracts have been obtained by English manufacturers.

Another interesting and conclusive proof of the success with which our engine build-
ers can compete for the supply of locomotives, is furnished by the following schedule,
prepared by Mr. W. P. Andrew, of the tenders for 94 locomotives received by the
Punjab Railway Company, in answer to a public advertisement in January, 1866.

Tender* for supply of Engines for the Punjab Railway.

Country from which Prices per engine

tender received. and tender.

£.

1. Germany, 8,166

2. England, 2,990

8. England, 2,960

4. England, 2,950

5. England, 2,850

6. England, 2,885

7. England, 2,810

8. England, 2,790

9. England, 2,750

10. Germany, 2,750

11. England, 2,685

12. Germany, .. 2,680

18. England, 2,680

14. Switzerland, > .. .. 2,650

15. England, 2.650

16. England, 2,600

17. France, - 2,595

18. England, 2,575

19. England, 2,500

20. Scotland, 2,424

21. Scotland 2,895

198 WORK AJTD WAGES.

Hie following extract from the " Times " is also interesting under this
head:—

" JSngligh and American Working Men.— In pursuance of instructions, United
States Consuls in Europe have been supplying to their Government some information
relating to the laboring classes, and the chief of the Bureau of Statistics has published
the results of the inquiry. The New York Times says :— "The general conclusion
to be drawn from the answers is unfavourable to the efficiency of English labor at
compared with American. It would seem that nine hours of an American's labor
are equal to about ten of an Englishman's, the superiority being nearly represented
by the ratio of 10 per cent The Consuls at Bradford, Sheffield, and other manufac-
turing cities and the chief of the Bureau himself, come to this conclusion after much
investigation. This is especially true of heavy manufacturing work, such as machine
or engineering work and the fabrication of hardware, cutlery, and other manufactures
of iron and steel. In all these branches, 900 Americans are thought to be equal to
1,000 Englishmen in the amount of work per week they will accomplish. This cor-
responds with the experience of our own manufacturers. It has before been observed
feere that in labors demanding enormous physical strength and endurance— like iron
puddling— the Americans were superior to the English ; while in patient, stead/
drudgery, the British ' navvy ' or Irish day labourer is much beyond the Yankee ; and
Mr. Brassey's experience is no doubt true, that the English day labourer is the cheap-
est labourer in the world, because he accomplishes the most for the money. The
American demands a toil with some peculiar stimulus to call out his best poorer.
Thus in a dangerous and difficult employment like lumbering, demanding great
strength and presence of mind, no nationality is equal to the American. The supe-
riority, however, of which we have spoken, seems to be less true in other branches'
and in cotton and woollen manufacture the British superiority is expressed by toe
ratios of 8 and 6 per cent The explanation given by the report of the greater effi-
ciency of American labor is probably the true one— that it lies in its greater 'adap-
tability ' owing to the superior education and intelligence of the American factory
workman, and in the more temperate American social habits. The English workman
requires a day or two to get over his Saturday night and Sunday drinking sprees.
The extent to which the English laboring class drink up their wages appears in a
melancholy form in this report. The Consul at Sheffield reports that great numbers
of working men stop work on Saturday noon, and do not commence again till the
following Wednesday. This is, in part because they need Monday and Tuesday to
enable them to recover from the effects of Sunday's drinking. ' Increase of pay, '
says the Consul at Birmingham, ' means increase of drink.' In Manchester, our Con-
sul reports that many sober working women complained that increased wages and
shortened hours of labor were a cur&e to the families, as the men were only the mors
tempted to drink. In Liverpool there seems a wide-spread and fearful demoralisation
of the laboring class from their intemperate habits. And thus from almost all the
manufacturing centres, our officials report a wretched condition of working men's
families and reduced efficiency of labor from the habits of intemperance prevalent
A curious fact also appears in these researches— namely, that a rise of wages does not
always produce more work. Thus in the coUeries of Leeds die product for each per-
son in 1864 was 327$ tons for 813 working days, or 21 } cwt for each person per diem.
In 1868 it fell to 817 tons, or 20 cwt per diem ; in 1878 to 17} cwt for each person
per diem. That is a reduction of production in ten years of 19 per cent, while wages

WORK AH1> WAGES. 199

lave risen 80 per cent end upward. In Manchester, the average earnings of a certain
mine were is. Id. per day in 1871 ; in 1872 the wages had more than doubled, and
yet the earnings were 2d. less per week for each man. The workmen averaged less
than fonr working days per week, while many only worked three days. The statis-
tical proof presented by the United States Bureau of Statistics of the terrible loss
and degradation to the English laboring classes produced by their drinking habits*
will not be one of the least of the good results accomplished by this able report"

VII Piece Work. — Mr. Brassey obviously views this subject from
an European point of view. We will first note wbat he says, and then
see bow far it is applicable to the very different conditions which obtain
in India. " It has always been the aim," says Mr. Brassey, " of experi-
enced employers to give to the workman a direct interest in doing his
"work with skill and intelligence. Slave labor in which the motive
41 of self-interest is wholly wanting, is, on that very ground as nnsat-
"isfactory in an economical sense, as it is repugnant to our moral sen-
" timents." Adam Smith remarks : — " The person who can acquire no
11 property can have no other interest but to eat as much and labor as little
" as possible. In ancient Italy, how much the cultivation of corn dege-
u nerated, and how unprofitable it became to the master when it fell under
" the management of slaves, is remarked both by Pliny and Columella."
The late Mr. Brassey always looked on day work as a losing game.
He preferred putting a price upon the work. This system was modified
to suit the habits of the people with whom he dealt. For example, the
Piedmontese were paid by the barrow load, a minute measurement peculiar
to their country. When the railway between Leicester and Hitchin was
begnn, the piece work system was abandoned, and the men were paid a
daily wage of 2«. 3d. each. The excavation then cost Is. 6d. per cubic
yard. Subsequently the system was changed and piece work introduced
when it cost only Id. The workmen sometimes themselves object to the
piece work system, saying, that when executed on equitable terms it is a
good thing in itself, but that the small contractor always wants to in-
crease bis profits by lessening the prices paid to the working people. This
objection is one peculiarly applicable to India. But we hardly ever ex-
perience the next exception. It is said, that it makes men overtask
themselves, contract intemperate habits, and thus prematurely ruin their
constitutions. The slaves employed as coffee carriers in the Brazils remove
bags of even three hundred weight on their heads a distance of 400 yards.
They are the most powerful slaves in the Colony, and are paid in propor-
tion to the work performed. They work with the most intense vigour, in

200 WORK AND WAGES.

order to earn as soon as possible a sufficient sum wherewith to purchase
their freedom, and generally succeed in accumulating the amount in four
. years. But they are a short lived race. In their devouring anxiety to
accomplish their object, they too often sacrifice their health by over exer-
tion, although they are well fed. We may here again quote Adam Smith,
who says, " The man who works so moderately as to be able to work
" constantly not only preserves his health the longest, but in the course of
" the year executes the greatest quantity of work."

Some years ago, all Government Engineers in India were strongly urged
to introduce in almost every case the contract system. But it was
pushed too far. Failures warned us that the nature and training of the
people of this country was not such as to allow the attempt to succeed.
Indian Contract Work is seldom if ever so well done as work carried out by
the usual Departmental Agency. It appeared at first to relieve the offi-
cers in charge of much labor. But it was soon found that this relief
was dearly purchased, and that the work of contractors required as much,
if not more, supervision than that carried out by daily paid agency. The
best plan seems to be to employ daily paid workmen, and to periodically
check by measurement the cost of the work done. In almost every case
constant supervision is needed. Piece work can of course in such simple
matters as breaking stone and digging earth be readily introduced : bot
even here vigilance is needed. In everything that can be counted mea-
sured or weighed true economy demands that the judgment should be
made according to number size and weight. The question of quality
often still remains and can be only gauged by inspection. In England,
bricklayers are paid by the number of bricks they lay : such a practice
with natives would not insure even safe work, unless the supervision was
very close. We have in India to meet an ever-pressing and never ceasing
desire on the part of nearly all with whom we deal to deceive. An open
and trusting nature is invariably " done. " Two illustrations may be here
recorded. The foundations of a certain building under construction by
contract were inspected by an Executive Engineer. He found them too
shallow, and ordered their deepening to be done while he remained near the
spot. On this being completed he directed their filling in with masonry
to be proceeded with and rode away. The 'moment his back was turned
the contractor refilled the trenches with earth, watered and tamped them,
and then ran up the masonry above. The work had not proceeded far,
when, cracks appearing, the trick was found out. On another occasion, an

WORK AND WAGKB. 201

Executive Engineer was inspecting the excavation for foundations of a work
which had been correctly lined ont by himself, when he found that the lines
of two large rooms had been altered so as to shorten each room by a foot
or two. He relined these end walls, ordered them to be correctly re-
excavated and rode away. The Contractor did not alter the excavation,
but stepped out the foundations course by course until the correct internal
dimensions of the room were obtained, bo that the walls merely rested on
the natural ground. Subsequent failures of these walls led to the dis-
covery of the fraud. Similar deceptions might be multiplied ad libitum.
Possibly education and practice may, in course of time, produce better re-
sults. "When an agricultural laborer begins to work on a railway,"
says Mr. Brassey, " he will lie down at 3 o'clock in the afternoon fa-
tigued and incapable of continuing his work, but after an interval of 12
11 months with more constant muscular exertion, receiving higher wages,
"and having better food, he will get into better condition, and will be able
"to perform his task without difficulty." Will a similar improvement
ever reach the Natives of India ? Have any signs of it yet been seen ?
Their genius does not lie in Engineering. Engineers see the worst sides
of their character. They thus form but poor conceptions of the value of
the live material with which they have to work. A distinguished Bengal
Engineer, it is true, gives them the following character : — " If they are not
" very truthful, are indolent, and sometimes troublesome or even exaspe-
" rating, it is no light thing that they are singularly temperate, wonderfully
" patient and good tempered, very susceptible to kind treatment and good
" management, and that strikes, drunken brawls and grumbling discontent
" are simply unknown.1' A late Bombay Municipal Engineer writes very
differently. He says, " It is almost impossible in India to get what we
" in England would consider even ordinarily good work. You may have
" heard of the Barracks which were condemned the other day. It is the
" same on railway works and everywhere throughout India. The Natives
" will not give you good mortar, or if you provide mortar they will not
" make good work. Masonry in India is at best bad." The experience
of our readers will doubtless alternate between these two extremes, and
they may perhaps be disposed to say in justification of the Indian Public
Works Department generally

A thirst so keen

Is ever urging on the vast machine

Of sleepless labor, 'mid whose dizsy wheels

The power least prized is that which thinks and feels.

September 1875. J. L. L. M.

202 SPEMCBB's PATEBT COMFEKSATOB FOB DISTANT SIGNAL WIBBS.

No. CXCIII.

SPENCER'S PATENT COMPENSATOR FOR DISTANT

SIGNAL WIRES.

[ Vide Plate XXTTL]

Description of an Invention for Compensating the Expansion and Co**
traction of the Wire Rope of Distant Signals of Railways. Bi
(the late) C. I. Spencke, Esq-, M.I.C.E.

Jubbulpore, 1875.
Evert Railway Engineer mast have felt the difficulty and inconvenience
caused by the expansion and contraction of the half mile or so of wire
rope which connects the distant signal with the hand lever. It is only
necessary to watch the operation of working the distant signal to be sa-
tisfied that a remedy of some kind is needed. The signalman pulls down
the hand lever without any visible result on the signal arm. He then
locks the chain, raises the lever arm again, tightens the expansion rack,
and again exerts all his strength at the lever, and after one or two such
operations, he finally succeeds in getting in the slack of the wire and drop-
ping the signal arm ; to raise it again, he lets go the lever with a jerk, and
frequently bends or breaks it, and after he has tried this plan in vain, he
walks some way along the wire and plucks at it and shakes it, and is at
last rewarded by seeing the signal arm resume the horizontal. A com-
mon practice of signalmen is to tighten up the rack in the heat of the
day, and leave it thus all night, when the contraction is very likely to pull
the signal partly down or to snap the wire, and thus disable the signal en-
tirely. Again, the counterpoise at the signal-post has to perform the
same operation reversed, which has cost the signalman so much labor,
i. *., pull back the whole half mile of wire to its original position ; for

PLATE XXIII.

BPEKCEH's PATENT COMPENSATOR FOR DISTANT SIGNAL WIRES. 203

this the ordinary weights supplied with the signals are insufficient, and it
is common to see them supplemented with broken chairs, thus increasing
the pall at the other end, and the tendency to break the wire.

If the wire works round a curve, instead of on a straight line, all the
above evils are intensified.

Spencer's Compensator provides a simple remedy for the above diffi-
culties. The accompanying Plate explains its working and construction.
The arrangement of the counterpoise at foot of signal-post is alter-
ed, so as to allow the arm to drop by releasing the wire, and vice versd.
The Compensator being fixed, as shown, in the centre of the wire rope,
the hand lever is pulled, and lifts the Compensator weight through a cer-
tain height, releasing by so much the second half of the wire, and allowing
the signal arm to fall to the position of caution. The hand lever is let
go, the Compensator weight falls, pulling the second half of the rope and
raising the arm to danger.

In case of contraction or expansion, the weight rises or falls, keeping
both halves of the wire uniformly tense.

This invention has been tried experimentally at a large station, for six
months in temperatures varying from frosty nights to the hottest days of
May, and on a wire rope 933 yards long, stretched over broken ground.
In all this time the expansion rack has remained a fixture, and the whole
arrangement has worked smoothly and easily without once requiring repair.
The advantages of the Compensator are —

1st Compensation of contraction and expansion ; uniform tension and
doing away entirely with the use of expansion rack and adjustment by
the signalman.

2ndly. The possibility of deflecting the wire at any angle vertical or
horizontal at the Compensator without any increase of friction, thus
giving facilities for getting round curves or obstacles or over uneven
ground ; for this purpose, the wheels of the Compensator are placed at
any angle to each other, or either half of the wire may approach the Com-
pensator in an upward or downward dixection — see below.

Horizontal deflection— Plan. Vertical deflection—Elevation.

Zrdly. The practical reduction of friction. The pull on the hand lever

VOL. V. — BSOOSD BBR1KB. 2 S

!04 spehcib's patent compensator tor

b equal to the friction of half the rope, pins a certain weight, and is found
n practice to be a much more manageable resistance than the friction of
.he whole rope. At the signal-poet, the pall to be overcome bj the
ttunterpoiee is only equal to the friction of half the rope, or in practice
nuch leas than half the friction of the whole rope, to that the second half
if the wire it especially seared from danger of breakage. The eonstinl
;ension gets the wire into good form, and pulls out tho bends and kinb
saused by leaving it slack.

ithly. All the signal gear in present use may continue to be Died
vith the Compensator with slight modification. All that is neceseerj is,
,o reverse the position of the counterpoise lever at foot of signal-post, w
ihown in the Plate, and to spike the expansion rack permanent!* in
me position on the hand lever; with this further advantage, that if jour
latent hand lever breaks, a piece of common plate bar will do to replace
t, omitting the expansion rack altogether.

The Compensator itself is easy to make. A pair of small grooved
rheels fixed on to one inch axles and turning true with the axles on iro*
meltings are required with chains and weights ; the weight itself veriw
n amount according to length of lead and other circumstances; for the
ib ove- mentioned lead of 933 yards with several deviations, both boruos-
al and vertical, a weight of 300 lbs. was found necessary. An ordinirj
traight lead of 800 yards works very well with about 260 lbs. If MJ
rreat excess over these is found necessary in similar circum stances, it is en
ndication of undue friction in some part of the signal gear, which shonld
>e sought out and remedied ; it is, however, no advantage to work with
he smallest possible weight; a margin ought to be allowed to overcome
toeasional or accidental friction.

The above invention is patented for India, and parties wishing to oie
he same, are requested to apply to Messrs. Burn & Co., Calcuta, from
rhom also working parts of the machinery may be obtained.

The use of bell cranks or levers instead of wheels, may in some cues
is preferable, and is included in the patent.

C. I. S.

FALLS OH THR SUKKUR CANAL. 205

No. CXCIV.

PALLS ON THE SUKKUR CANAL.

[ Vide Plates XXIV., XXV., XXVL]

By Lieut.-Col. J. LbMssubibr, R.E.

Karachi, 16th February, &16*

Ths Plates show the falls which were constructed in 1871-72 on the
Bokknr Canal.

This canal was opened in 1871, and the experience gained during the
first inundation showed plainly that the mouth at the head of the pass
would not answer when the river was in flood. After the canal had been
open about two months, there was a deposit of 11 feet of pure sand at
the head, tapering down gradually to a depth of about 2 feet at the 4th
mile. It became necessary therefore to open a new mouth at once, and
the spot chosen was close to the village of Hahuja about four miles above
Sukkur. There was here an old channel of the river, locally termed a
dhandk, and though it had silted up somewhat, the supply it drew from
the river was sufficient, and could be depended on down to a certain
height on the river gauge at Bukkur. A new mouth had been com-
menced here about two years before the canal was opened, but when a
portion of the excavation had been completed, the work was suspended,
as it was decided that the original mouth should be first tried.

The new mouth was commenced with a bottom width of 16 feet, and
side slopes of 1 to 1. The surface slope was 1 foot 10£ inches a mile, and
to enable the channel to stand the high velocity due to this slope, it
was intended that the bed and slopes of the canal should be faced with
rough stone pitching.

206

FALLS ON THE 6UKKUR CANAL.

When the time came however for completing the work, it was decided
that a preferable plan would be to limit the hydraulic slope to 6 inches a
mile, and to meet the difference by the construction of vertical falls near
the junction with the old portion of the canal. The 6ite chosen for the
falls was about 400 feet above the junction, as the new mouth here cut
through a spur of limestone rock.

From the head regulator to the falls, about l£ miles, the new mouth
has a bottom width of 60 feet, and side slopes of 1 to 1. The depth of
water required to give the full supply, with a fall of 6 inches a mile, is 9
feet. The mean velocity is 2 27 feet per second, and the discharge 1,432
cubic feet. Below the falls the bottom width of the mouth is 31 -25 feet,
with side slopes of 1 to 1, and the depth of water is 13 feet. The differ-
ence of level between the beds above and below the falls in 7*55 feet, and
of the water lines 3*55 feet.

The plan of the falls is shown in Plate XXIV. The crest of the mi-
sonry portion of the weir is 9 inches above the bed, and it is divided
into five bays of 11 feet each by piers 4 feet thick. The thickness of the
weir is 2 feet 6 inches : it is in fact nothing more than a brickwork facing
to the rock, forming an even surface Against which the gates can slide.
The design of the masonry of the falls requires no particular description,
as there is no cistern or basin, and the lower retaining walls are simply
continuations of the abutments. The bed and banks of the mouth below
the falls, as far as the junction with the canal, a distance of about 400
feet on a curve, are protected with rough stone pitching, laid dry, about
1 foot 6 inches or 2 feet thick.

The plan of using sliding gates to form the weir, instead of building up
a mass of masonry above the bed, is, it is believed, entirely new, and as it
has answered so well at the Sukkur canal for four seasons, a description
of it may not be uninteresting.

The gate is constructed of 4-inch teak plank with a strip of 3£-inch
angle-iron along the top and bottom of the down-stream face. The gate
is strengthened at front and back by four strips of f -inch plate iron 4
inches wide, and by two cross pieces of 3^-inch angle-iron at the back, as
shown in Fig. 7, Plate XXV. The gate, when lowered to the full extent,
rests on a piece of teak 11' 8£" x5'x 4£", fastened to the brickwork
by bolts, and its top is then level with the crest of the masonry, or 9 inches
above the bed of the canal. It slides up and down against two vertical

VI.

PLATE XXVI.

FALLS ON THE SUKKUR CANAL

(Mmlarftd Drawing* if Omlu).
Scale ti* 4 ftet - 1 inch.

S'V'\j^A/sJVN*Jh

TTxvXWW

^/Mm^AM'maffmsm//.''

k^^VVWU^^

vyvvvyv1-

-■-'4

..f-'-.j

(OJ

t 9-

'W^Vlyv^

* 1 ^

.rf-

4 w

FALLS ON THE SUKKUR CANAL. 207

straining pieces of teak, scantling 5" x 4£", fastened by lewis bolts to
the piers, which are recessed for the purpose ; the thickness of the pier
being 4 feet, and of the upper cutwater 8 feet 3£ inches.

When the full supply is going over the gate, its top is 5 feet above
the level of the bed, or its bottom 9 inches below the crest of the ma-
sonry. The man in charge of the falls has orders to keep the gauges at
the head regulator and at the falls reading the same, and when this is the
case, the surface slope of the water is 6 inches per mile. If less than
9 feet is admitted at the head, the gates at the falls are lowered until
the two gauges read the same. If at any time it is necessary to admit a
greater depth than 9 feet, the gates are raised.

The apparatus for raising or lowering the gates is very simple. Across
the cutwaters a teak beam, 9 inches wide by 12 inches deep is laid, and
bolted down to the piers by a 2-inch bolt. The screws which are
attached to the gates are of 2-inch rod cut to £-inch pitch : they pass
through holes cut in the teak beams, and are wound up and down by a
brass nut, which turns between two iron plates bolted to the beams as
shown in Fig. 8, Plate XXVI. The brass nut is 7 inches deep, the lower
4 inches being circular, with a collar \\" X 1£", and the upper 8 inches
hexagonal 3£ inches across. The nut is turned by the iron handle, shown
in Fig. 10, Plate XX VI., two of which are required for each gate.

It would be easy, of course, to have bevelled wheels to turn both the
screws of each gate at once, bnt this would add to the expense ; and as
long as the two men are careful that they make simultaneous half turns of
the handles, the gates are not found to jam. As the gates are very
quickly raised or lowered, and they never have to be shifted much at one
time, one pair of handles is found to be sufficient for the whole of them,
and this requires two men for the establishment for looking after the falls.
In the cold weather, when the mouth is dry, the wood and ironwork of
the gates is well dressed with common fish oil, procured from the fisher-
men on the river.

The gates are 11 feet 8 inches long, and as the opening in which they
slide is 11 feet 8£ inches, they have a play of £-inch at each end. There
is also a small play between the front of the gate and the back of the
masonry of the weir wall : £-inch is shown in the Plate, but it is in reality

less than this. The 4-inch strips of plate iron are countersunk into the

front of the gate, but not into the back, and all the rivets and bolts as

208

HK SUKKUK CANAL.

well, so that the face of the gate is perfectly level and flash ; and then it
no reason wlij more than ^incfa play should be given. It was considered
advisable, however, ae the gates had to be made in Karachi and sent up
to Sakkur ready to be pat up, to allcw for j-incfa play when building
the masonry.

One advantage of this kind of fall, and a very great one, is tbatil
suits a variable depth in the canal, as the gate can be raised or lowered
according to the depth of water admitted. Another advantage appears to
be, that the action of the water upon the bed aod banks below the fall ii
reduced to a minimum. The canal is merely protected by a comparative'.'
thin layer of rough stones procured from the excavation and laid dry,
and up to the present time no repairs of any sort have been required.
The bed and banks of the canal above the falls are almost as clean as the
day they were cut, as whatever the depth of water is, the sarface slops
is kept fixed at 6 inches a mile, and the mean velocity never exceeds !j
feet per second.

J. LeM.

THI LIMIT or ILAST1CITT.

THE LIMIT OP ELASTICITY.

Remarks on Major C. A. Good fellow's " Notei or,
tie Neutral Axis in a Beam subjected to Transverse
I. C. Douglas, Esq., East India Govt. Telegra
Soe. Telegraph Engineers, Sfe,, fyc.

Tbe term "limit of elasticity " or "elastic limit" nas adc
ledge of the phenomena of resistance of materials was 1
than it is at present, and when in fact the received the
respect to the relation between elasticity and set were
more complete knowledge of the phenomena and conseqi
the theory do not necessarily imply departure from esta
the facta obtained by experience remain eqnaily factt
theory ; but the theoretical explanation of the facts bei
nomenclature applicable nnder the erroneous theory reqo
cation as will render it proper to convey the new ideas. '
to avoid confusion, or the retention of theoretical ideas ]
It has become necessary either to adopt some other term
of elasticity ;" or to clearly recognize that the term no 1
that idea it was originally selected to convey, and thf
new definition.

It was presumed that within a certain limit, material
t\utic and no set resulted from the application of a 1
proof load ; bnt the assumption of snch a strictly defin

• Ho, CLXX., Proftatimial Pipm an Indian Knilnnrinf, [Bap

1 f i »

■h

til

210

THE LIMIT OF ELASTICITY.

variance with what is known of other physical properties of matter; it was
based on imperfect data, and therefore never strictly defined. It was at
length proved that a set resulted from the application of a load far less
than the proof load, the experiments of Fairbairn and Hodgkinson prove
this conclusively ; but the inference that every load, however small, which
produces a permanent set when first applied, must necessarily cause frac-
ture if applied continuously or repeatedly, appears to have been an
assumption as erroneous as the previous one of a limit of elasticity. Such
an inference leads to a contradiction, for it is known that materials do not
in practice fail under such relatively small loads ; e. g., iron will receive a
set under a load far below what it is usually loaded with in practice, bnt
practice is justified by experience, and an engineer is not condemned as
Tash for adopting four as a factor of safety with a material which is known
to receive a set with a load only one-tenth of the ultimate load. If the
hypothesis be corrected by an appeal to experiment and observation, it is
found contradicted by observation, and by the experiments of Lloyd on
successive breakages of the same bar, and by Kirk aldy 's experiments. After
a careful examination of all the modern works on the subject which could
be found in the British Museum Library, and the fiibliotheque Nationale,
Paris in 1847, the following conclusions were adopted as expressing the
present state of knowledge of this subject.

" It was supposed that no set was produced by loads within the limit
of elasticity, but it is now known that loads well within this limit do cause
a set ; and it is highly probable that every load, however small, causes a
set on its first application, the set in the case of a relatively small load
being inappreciable. The set due to the action of a load within the limit of
elasticity, is not increased by repeated applications of the load ; and, after
having received such a set, the material is more perfectly elastic for loads
not exceeding that which produced the set. If a load exceed the limit of
elasticity of the material, repeated applications of the same load cause
an increasing set, until the material is either fractured or fails by being
distorted so much as to become useless. The limit of elasticity or of per-
fect elasticity, the elastic strength or the proof strength, of a piece of
material, is now more correctly defined as the greatest stress it will bear
without injury — i.e., the greatest stress which does not produce an increas-
ing set on repeated application." (Manual of Telegraph Construction,
page 31).

TBI LIMIT OF ELASTICITY.

211

Unfortunately the term limit of elasticity is frequently used without
being defined, and sometimes the obsolete definition is given and the
student is confused by the evident contradiction. It will be s.en * '
the above definition does not necessarily raise factors of safety formerly
adopted ; it may act the other way, for the hasty conclusion that a per-
minent aet necessarily implied ultimate fracture, may in some cases hare
led to ike use of factors of safety unnecessarily high.

J. CD.

[* <* fry Editor — Statements substantially the same as the above will be found in Arte. 87 and 88 of
P«n Lot the Roorkee College Manual of Applied Mechanic*, 1878, by Oapfc. A. Cunningham, RA]

VOL. V,»—beooHD SERIES.

2 F

1 PI L« DRAWING.

No. CXCVI.

CLAWS FOR PILE DRAWING.

Thk contrivance here shown was found useful for drawing the miio piles
of the Cofferdams at Apollo Bander in Bombay. Its only advantage
over other means of attachment is, that it grasps the pile without damag-
ing it, so firmly, that there is no risk of slipping or breakage unless the
wood be fairly torn asunder.

The piles were 9 inches square, and the
bolt holes for the npper tier of waling piece*
j 1 \ inches diameter, so the bolt upon which
tbe two claws hinge, was made of the sum
/' diameter to fit the same hole.

I, Tbe power is applied by means of two

of " Weston's Differential Blocks " suspended
from above, or two 10-ton screw jacks resting
on pieces of wood, which are loosely clamped
on either1 side of the pile, through which the
£LEV*TI0N pressure is transmitted directly to the groond.

Tbe claws are made so, that when tbe power is
applied for drawing the pile, the compressive
force exerted at tbe two lips is equal to tbe
force exerted at the bolt bole which tends to
split tbe pile, and would in many instances
do so if this tendency were not counteracted.
Those piles which have already been drawn
by this method were driven from 10 feet to
15 feet below tbe groond surface, through strata of soft mud, stiff clay,
and gravel into a bed of bard moomm, and the power required to draw
them varied as nearly ae can be calculated from 5 tons to 10 tons accord-
ing to circumstances, yet in no instance where the claws were used, were
the edges of the piles damaged.

The most advantageous way of working is to draw the pile from four
to six feet with the differential blocks or screw jacks, and then hoist it the
rest of the way by a jib crane, light tackle, or other means at band.

SPECIFICATION** FOR ROOF COYBRINQ8. 213

No. CXCVII.

SPECIFICATIONS FOR ROOF COVERINGS.

[ Vide Plates XXVH to XXXTT.]

Extracted from the Schedule af Specifications and Bates Jar the use
of the ith Circle, Military Worts. By J. P. C. Anderson, Esq.,
Assoc. Inst. C.E., Supdg. Engineer.

[The following specifications are based on the experience of many years
and in many different parts of the Punjab, and embrace the details of
the latest practice in the several descriptions of ftork detailed below. Al»
though prepared for use in the 4th Circle of Military Works, in the
stations of Umballa, Jnllundur, Ferozepore, Mooltan, Dagshai, Kasauli,
&c., they will be found applicable to most stations in Northern India, and
useful to Engineers throughout the country].

Allahabad Tiling -

(a).— Single tiling consists of one set of flat tiles laid on battens, with their verti-
cal junctions covered with a layer of semi -cylindrical tiles, all the tiles are to
• be set dry.
(Jb). — Doable tiling consists of a set of flat tiles laid on battens with their vertical
junctions covered with a layer of semi-hexagonal tiles, over which is placed a
layer of fiat tiles with their vertical junctions covered with semi-cylindrical
tiles, all the tiles are to be set dry.
(<?).— All tiles are to be made of thoroughly well tempered clay, they are not to be
dressed or shaped till they are sufficiently dry to prevent their getting out of
shape, and are not to be put into the kiln till they are thoroughly dry. In
moulding the tiles, the greatest precaution is to be taken that the moulds fur-
nished to the men making the tiles are accurate, and that similar moulds are
perfectly true in their sizes,
(i). — When the manufacture of tiles is in progress, all the moulds must be exam-
ined and measured by the Executive Engineer or an Assistant Engineer every 10
days, to see that they have not got out of shape.
VOL V. — SECOND SERIES. 2 Q

I I

• 41
f.

~.\

t . "!

ii
it

I i:

4 ' .'

< i

^ i

214

SPECIFICATIONS FOR ROOF COVERINGS.

(*)•— The tiles axe to be thoronghly burnt and Bound without flaws, well shaped

with sharp square edges, and to have a good metal ring.
(/)• — All buttons, swellings, and projections, are to be formed solid in the mould,

and not attached to the tile after it is moulded.
(?)• — The size and shape of each separate description of tiles are to be precisely

similar.
(A).— The following points are to be carefully attended to in laying the tiles : —

1. The battens on which the first layer of pan tiles rest, must be of one uni-

form scantlings with their sides cut square, they are to be placed
parallel to each other at central distances of 1 foot, and with their
upper surfaces in one plane.

2. The two ridge battens are to be pnt on first at the required distances from

the apex of the roof to suit single or double tiling as the case may
be, and the remainder at the proper intervals down to the eaves ; the
length of the eaves being regulated so that the roof shall terminate
with a whole tile and be not less than 15 inches in breadth.
& All tiles must lock freely and properly into each other, so as to set per-
fectly one on the other, and form an even upper surface.
(i> — The upper layer of pan tiles are to be placed immediately over the lower
layer, with their sides resting on the semi-hexagonal tile, and the semi-cylifl-
drical tiles resting over the semi-hexagonal tiles,
(ft). — Whenever it is necessary to mafce tiles for hips, valleys, &c, &c, they should

be cut with a saw to the required angle before the tiles are burnt
(2). — Any tiles that are cracked, chipped, underburnt, or damaged in any way,

must not be put into the roof,
(m). — The tiles must be laid in accurate regular lines, so that a string held at the
middle of the outer plane of the semi-hexagonal or semi-cylindrical tiles at the
apex of the roof and at the eaves, shall pass over the centres of all semi-hexa-
gonal and semi-cylindrical tales in that line.

At all angles and exposed points where the roof is liable to be lifted by the
force of storms, the wall plates are to be bolted down with f-inch round iron
bolts, from 2 to 3 feet in length buried into the masonry ; the end of these bolts
in the masonry are to have broad heads to prevent the bolt being drawn out.

Corrugated Galvanized Sheet Iron.—

(a). — As it has been found that kelo (or Cedrus deodoro) corrodes sine when the
two are brought into contact. To prevent injury to the galvanizing of the cor-
rugated iron, battens of chfl (or Pinna longifolia) are invariably to be used for
the iron to rest on ; where however kelo wood rafters exist, strips of chil wood
are to be nailed down over them before the corrugated iron is laid on.

(ft). — The success of corrugated iron as a roof covering depends to a great extent |
on the rivetting. The holes for the rivets should always be made in the ridges,
not in the furrows of the sheet ; when in position they should, in the first in-
stance, be punched with a fine thin pointed punch, to mark the points, and tb0
bit then cut out clean with a full sized punch, and punching block. In mark-
ing the points for the rivets, any two sheets to be connected together are to be
placed with what will be the lower surface uppermost, and one over the other*
in their proper positions, with a 6-inch lap for the horizontal joints, and in

Q»V *

I F,.. I. .
I Fie. J...

DBTAItLB

OF A

ROOF OF FIR OR DEODAR TIN

Or 24 HIT SPAN,

HUITABLB TO CAHKT A COVERING C

i "

IR,

IB.

I :

>..-

FLA TE JXtX

D1TAIL»

Ft«. 11..
Pk«. 12.
ft*. 13.
Fia. 14, ]

or a

ROOF OF FIR OR DEODAR TIMBER.

OF 24 FXET SPAN,

SUITABLE TO CARRY A COVBEfNO OF

GSIIWYN IR AILAHAIAI TILING.

txrinx.

Trubirb 7J PSKT CKXYEAL »TE»YALA.

Scale for truss, £ inch to afoot.

J o

Scale for details, J inch to afoot.

-4

to afoot.

22*" x 12" * 4'

Cross section on CD.

!_i

sqttare

• 2 »

(Signed). ^^

ALEX. TAYLOR, Cot.,'1" ^
Chitf Eyjinttr, Militari/ Works.

IT N

i '/

i •

PLd TE XXX.

DUTAIL1

OF k

ROOF OF FIR OR DEODAR TIMBER,

OF 24 FIIT SPAM,

SUITABLE TO CtftRY A COVERING 09

GOOIWYN OR ALLAHABAD TILING.

TSVWKS 7| YfiST CIHTRAL 1MT*«VAL0,

&»** «/ai 22** x 16* X *

FUhing pier** \6

.3.

■ 1

Section en A.B

Tie beam

6 ?

Stene temp/ate

Fig. 18.

■ — ^^

'*'■

„
i*

(Signed). - - --- —

ALEX* TAYLOR, Col.,

Chief Engineer, Military Works.

•:.t

- >

! * •

•4

«• ^

. »

•r

PLA.TF. XXXI.

DETAILS
on

ROOF OF FIR OR DEODAR TIMBER

Or 24 FEET SPAN,

SOITABLI TO CARRT ± COVKEINO Of

BOODWYN Oil ALLAHABAD TILING.

TjUJBSM 71 FCKT CENTRAL INTKBYAL&

Scalt 2 feet to 1 inch.

Sretkm of ridge pole
bttntt* trtuiet

J. P. C. Anderson,

Supty. Sngr., 4(i Circle,

Military H'orli.

SPECIFICATIONS FOR ROOF COVERINGS.

215

'h*

the vertical joints with one corrugation Up, for a 5-inch wide corrugation, and
Section of Punch. two corrugation lap, for any cor-

rugation less than 6 inches in
width, and the fine pointed thin
punch driven through both
sheets. The sheets are then to
be placed, with what will be
their lower surfaces uppermost, and the full sized bolt holes cut out clean.
(c).— In fixing the rivets, the sheets are to be placed in position on trestles ] 8 inches
high, and the rivets passed through from below, and held np with the rivet heads
on an iron bar resting on a block of wood placed on the ground, a galvanized
iron washer is then put on, and the bolt rivetted with a light hammer, and fin-
ished off with a cupping tool placed on the rivet, and the head beaten out
(<f ).— When the sheets of iron have thus been connected, they are to be secured to
battens of the proper dimensions, placed at central distances of half the lengths
of each rivetted sheet, with j-inch round or J-inch square cramps, as shown
below, with a play of J-inch between the cramps and the batten, to allow

Cramp for fixing iron on Roof,
1 full site.

Lead Walker*.

for contraction and expansion. These cramps are to be fixed at every second
batten, and their longitudinal distances apart are to be the width of the exposed
portions of the sheets.
(e).— Wind bars of wronght-iron, 1§* X J*, 1 inch angle-iron, or {-inch round-iron,
are to run the whole length of the roof, at three batten space intervals, com-
mencing from the eaves batten, and secured with iron cramps, as described
above.

216 SPECIFICATIONS FOR ROOF COVERINGS.

, • <

(/).— -The eaves sheeting is to consist of -^-inch galvanized sheet iron, 1 foot wide,
cut into shapes.

At all angles and exposed points where the roof is liable to be lifted by the
force of storms, the wall plates are to be bolted down with f-inch round iron
bolts from 2 to 3 feet in length, buried into the masonry, the ends of these bolts
f in the masonry are to have broad heads to prevent the bolt being drawn out.

i (| (^). — The connections at the gables, at chimney, or air shafts, or other projecting

' masonry, to be rendered water-tight by the introduction of 20 B. W. G. galvan-

ized iron flashing ; in the case of gables 18 inches wide and the length of the
sheets used in the roof covering, and in the case of chimney or air shafts 2 feet
broad and the entire length of the shaft

In the case of chimney or air shafts coming through the slope of the roof, a
cross gable roof is to be made, 1 foot wider (6 inches on either side) than the
shafts, to prevent the rush of water from the roof coming against the shafts.

MucL-

(<x). — To consist of good clay, 4 inches deep, damped, well beaten down, clay,
plastered and leeped, laid on 4 inch diameter rolls of sirkanda (reed) resting on
one layer of perfectly well burnt stock-moulded 1st class tiles, 12* X 6* X 1'
soaked for three hours under water, and laid with their sides drawn up with
mortar.

(6). — To consist of good clay, 4 inches deep> damped, and well beaten down, either
on brushwood placed on matting on sirki, or sirkanda (reed) resting on raft-
ers or battens at 1 foot central intervals, the upper surface to be mud plastered
; f and leeped.

on cioth.-

(a). — The cloth to be used is to be the double warp cloth from the Cawnpore Mill*,
and is to be soaked in a composition made of 15 lbs. pure linseed oil, 6 fts.
finely pounded litharge, and one part pure bees wax, all boiled together.

(I). — Great care must be taken to ensure the use of none but pure linseed oil, as
the success of the cloth being made waterproof depends mainly on the use of
pure linseed oil, which is the only oil which dries properly, and if mixed with
other oils it loses this property.

(c).— Five maunds of pure linseed oil are to be placed in an iron caldron 2 feet
broad at the top, 1 foot broad at bottom, 4 feet high and 5 feet long, and boiled
, over a charcoal fire for about five hours, or till small bubbles rise on the surface,
the litharge finely pounded is then to be added, the whole well mixed and the
boiling continued for another two hours, the mass being stirred every quarter of
an hour, after this, the bees wax is to be added ; when the wax melts, the whole
composition is to be well stirred, when it will be ready for use. So soon ss
the composition is ready for use, the fire is to be lessened and only sufficient
kept up to keep the mass in a liquid state.

(<*>— Each piece of cloth is about 46 inches wide and 46 feet in length ; in coating
it with oil one end is to be drawn out and passed (tee sketch on page 217) under
the roller B at the bottom of the caldron, then carried between two guides 0C, it
Ss then to be drawn over a series of rollers EE, and finally wound round a dram
on which it remains till used. The object of the guides CC, is to remoYC all

SPECIFICATION** FOR ROOF COVERINGS.

217

surplus composition from the cloth, and return it into the caldron instead of

losing it daring the pas-
sage of the cloth over
the rollers ; the guides
should consequently be
placed sufficiently close
together to remove the
surplus composition.

To avoid the difficul-
ty of getting the cloth
under roller A, the se-
cond piece to be coated
with oil should be tack-
ed to the end of the first
piece before the latter
is drawn through the

- oil, and is to be detach-
ed when the head of the
second piece is well out-
Bide the caldron.

(e). — The strips of pre-
pared cloth are to run
across the roof, and not
longitudinally.

(/ ). — Before placing pre-
pared cloth as a cover-
ing over shingled roofs,
the edges of shingles
at the ends are to be
rounded off, to prevent
the sharp edges injuring
the cloth. The cloth is
then to be rolled off
either on the ground or
placed in position and
secured at the top, and
is to be kept in that
position till it shrinks,
it is then to be made to
pass down the Bteps of
the shingles, and is not
to be stretched tight,
and it is to be tacked down with tin tacks } inch long with broad heads.

Shingling.—

(a).— All battens to be dressed to one uniform scantling of 2 inches by If inches,
and secured to the roof timbers placed at central distances of 6 inches and in
parallel lines.

(£). — The shingles to be cut with square edges, and of one exact uniform lengths

SPECIFICATIONS I

I KOOFCi

.'BRINGS.

of 20 inches, to be laid on battens at 6 inches central intervals in three lajm,
with the head of the first layer abutting against the fourth batten from the esd,
and the end of the fourth shingle over-lapping 2 inches, the head of the first
shingle. The shingles are to be laid on with intervals of ^incb, and raid: to
break joint. In the dry season the shingles are to be soaked in water in half
casks before being pot on.
(c). — The nails are to be made of J-inch iron wire, they are tone S| inches long wilh
broad heads, and with the ends for a length of only
1-inch beaten ont to a point, and they are to be made
red hot and dipped in coal tar before Ihoy are at/A.
(d). — Each shingle is to be secured by only two nails dri™
one on either side of the shingle, the first nail is to be
in the first shingle and the second nail in the ehiiigte
immediately above, this gives one nail per shingle.
> At all angles and exposed points where the roof is

liable to be lifted bytheforceofstornis,thewallplaM
are to be bolted down with 1-inch ronnd iron bolts,
from 2 to 8 feet in length buried into the maaonrj,
the end of these bolts in the masonry are to nave broad
heads to prevent the bolt being drawn ont.
(«).— The connections at the gables, at chimnev, or sf
shafts, or other projecting masonry, to be rendered
water-tight by the introduction of SO B. W. 0. gal-
vanised iron flashing ; in the case of gables IS lochs
wide and the length of the shingles used in the not
covering, and in the case of chimney or ail shatn 1
feet broad and the entire length of the shaft

In the case of chimney or sir shafts coming tbrongrt
the slope of the roof, a cross gable roof is to be made,
1 foot wider (6 inches on either side) than the shafts,
to prevent rnsh of water from the roof coming against
the shafts.

Slating,—

(a). — The slates are to be laid either on planking or on
battens placed at central distances of one-third the
length of the slates less 2 inches, that is, for 20 inch
slates, the battens are tone G inches central distances,
'all battens on which slates rest ara to bo dressed to uni-
form scantling second to the roof timbers.
(»).— The slatea to be used are to be what are teebni.
call; called Drtehesses, 24* x 12*,or Countesses, SO* x
10*, or such other sites as may be procurable, not less
than 19 inches in length ; they are not to exceed f
inch in thickness, or to be less than f-ineh, an la be
sound, with smooth, even surfaces, free from tracts,
scales, fissures, or other imperfections, are to be dres»J
truly square, and are to be gauged to the required dimensions ; all slatea vita
broken corners, crooked, or in winding, are to be rejected.

SPECIFICATIONS FOR ROOF COVERINGS. 219

(c). — On battens, the slates are to be laid as described in para, (a) above. The
heads of slates are to rest f-inch on the fourth batten from the end, which will
give the fourth slate a lap of 1 finches on the first slate, see sketch on page 218.
(•*). — The slates are to be secured with galvanised iron nails, If inch long, one
per slate, placed on the middle line of the slate, and into the batten immedi-
ately below the one on which the head is resting ; with a 20 inch slate the nail
hole will be 6| inches from the head,
(f). — The nail holes are on no account to be punched, but must be drilled and
countersunk with a bit, having a tapered or bevelled shoulder, so as to receive
the swell of the nail head, and prevent it coming in contact with the next upper
layer or course of slates.
{/). — Every course of slates is to break joint with the course above and below it —
at least 6 inches in the case of Duchesses, and 5 inches in the case of Countesses,
i. ?., the centre of each slate to occur exactly over the joining of the two slates
above and below it.
(g). — Whole slates are to be laid throughout the entire surface of the roof, save at
the commencement of the course near the gables ; where it may be necessary to
break joint.
(&).— The connections at the gables, at chimney, or air shafts, or other projecting
masonry, to be rendered water-tight by the introduction of 20 B. W. G. gal-
vanized iron flashing ; in the case of gables 18 inches wide and the length of
the slates used in the roof covering, and in the case of chimney or air shafts
2 feet broad and the entire length of the shaft

In the cane of chimney or air shafts coming through the slope of the roof,
a cross gable roof is to be made, 1 foot wider (6 inches on either side) than the
shafts, to prevent rush of water from the roof coming against the shafts.
(»> — Stop flashing to be in sheets of the required sizes, having two -thirds slipped
in under the bottom of the slates, and one-third turned up at right angles next
the masonry.
(*). — Top flashing to be 6 or 7 inches wide, having 8 or 4 inches built into the
masonry during its construction, and the remaining 3 inches bent down over
the turned-up portion of the stop flashing.
(/). — The ridge to be secured from leaking by the portion of the ridge pole project-
ing above the roof being covered with zinc sheeting. The sheets to overlap each
other 8 inches, to be bent over the ridge pole (which should project 8 inches
above the top of the roof ), and to lap at least 6 inches over the top course of
slates at each side of the ridge, they are to be prevented from blowing off or
buckling up, by straps of hoop- iron painted, and bent over the sheets at intervals
of 2 feet apart The whole (including the hoop iron ridge sheeting and wooden
ridge piece) to be bolted through.

Tiled and Terraced.

(a). — To consist of one layer of flat tiles soaked in thick whitewash set in lime
mortar laid over 2\ inches concrete placed on two layers of flat tiles set in Kme
mortar.

(ft). The lower layers of flat tiles arc to be 12* x 6* x 1*, laid in two courses
over scantlings placed 1 foot central distances apart The first layer of tiles is
to be set with their sides drawn up with mortar, the second layer of tiles to

220 SPECIFICATIONS POR ROOF COVERINGS.

break joint with the lower one, and to be embedded in mortar, and to hare
their sides drawn up with mortar,
(t). — The mortar for the plaster to be composed in the following proportions, all by

measure : —

1. At Jnllundur, 1 part fresh slaked stone lime, 2 parts charcoal burnt fresh

slaked finely sifted kunkur lime, and 14 parts fine sifted surki of tho-
roughly well burnt clay.

2. At Dalhousie, Dharmsala, Kangra, Kasauli, Dagshai, Subathu, Jntogh,

and Umballa, of 2 parts fresh slaked stone lime, and 8 parts fine sifted
surkf of thoroughly well burnt clay.

3. At Ferozepore, of charcoal burnt fresh slaked finely sifted kunkur

lime.

4. At Mooltan, of 2 parts fresh slaked stone lime, and 8 parts clean river sand

or fine sifted surki of thoroughly well burnt clay.

(J). —Great care must be taken to see that the surki is not made of 2nd class bricks
or under-burnt clay, and that none but clean sand is used.

(0) — In making the mortar with quick lime, fresh quick lime is to be slaked under
water into a paste in a tank, half cask, or bucket, and allowed to stand for a
fortnight with the water the whole time 1 foot above the paste, after which the
water is to be run off, the proper proportion of surki added, and the mass worked
up in a mortar-mill into a stiff plastic paste : it is then to be ground fine in a
hand-mill.

Particular care is to be taken that the mortar is not drowned with water
while undergoing hand-mill grinding.

(/). — The tiles for the layers under the concrete are to be perfectly well burnt
stock-moulded, well shaped flat tiles, 12* x 6* x 1*. and are to be soaked un-
der water for four hours immediately before being used.

(£).— The concrete is to be made in the proportion ot 1 part of dry mortar to 3 parts
of unburnt kunkur, the sittings of kunkur lime, the sittings of surkf or broken
stone in £-inch cubes all by measure. The unburnt kunkur, siftings of surkf or
broken stone must be soaked under water for three hours immediately before
being added to the mortar.

After the concrete has been spread, it must be wetted and beaten with slight
quick strokes with a hand flail, till the mortar is drawn up to the surface, and
the mass is well set.

(/*)•"" Covering the concrete iB to be a layer of tiles similar to those described in
para. (/), and soaked in thick whitewash with their sides drawn up with mor-
tar as described above.

(0-— Over the last layer of tiles iB to be spread 4 inches of clay, for six months,
to allow of the concrete to set, after which the clay is to be removed.

(A). — At the junction of a tiled and terraced roof with a wall, a row of tiles 12
inches long is to be set 6 inches into the wall, over this is to be laid another row
of tiles breaking joint with the lower one, and let 8 inches into the wall, the
lower surface of the first tile is to be 2 inches above — what will be the complet-
ed surface of the tiled and terraced roof, and filled up with concrete, alter the
concrete is finished. This is done to prevent the leakage of the roof with its
junction with the wall.

PLATE XXX II

■

if
V

r*l

mux
Fiji*

i —

<5 + tf

V 6

/2-

• )

l r^r~^ -\J '

. i:

"' J

J. P. C. Aummnuw,

Military Work§.

r;.

1' •!

i".

SPECIFICATIONS FOR ROOF COVKRlNOfl.

221

Thatch.
L Bamboo Frames.

(a).— The bamboo work of a roof is to consist of rows of single whole bamboos at
3 feet central intervals placed longitudinally, on which, and crossing them, are
to be tied rows of single whole bamboos arranged at 9 inch central intervals,
running across the roof — that is, from the apex to the eaves ; over these, and
crossing them, are to be laid bamboos split in halves arranged at 6 inch central
intervals, and firmly tied down with ban string. The bamboos are to be tied
together at all points of their intersection with each other.
The bamboo framework is to rest on, and secured to battens at 3 feet cen-
ral intervals resting on common rafters, or to purlin rafters also at 3 feet
antral intervals, resting on the principal rafters of a truss.
-Newly cut bamboos are not to be used, as they are liable to weevil (gun).
Repairs of bamboo frame may consist of petty or general repairs. The
ver will always be executed on the roof unless specially ordered to the con-
7 j in the latter it may be necessary to remove the frame and repair it on
ground. This will only be the case with tied frames.
i most cases, when a frame is removed from a roof for repair, it will be
TOical to break it up and entirely remake it In this case, the serviceable
ial will be selected. The rate to include removing from roof, selecting
ial,&c.

ere mats are laid over a bamboo framework, they will be laid with their
overlapping, and tied down by battens of split bamboo, so laid that in
e shall 1 superficial foot of matting be left without its batten.
0»

several descriptions of grass roofs are to be well and tightly or closely
id in one, two or three layers, according to circumstances,
massing of a roof, if properly executed, should not sink perceptibly
wight of a man standing on it, nor should the blades of grass be
by the feet of a man walking over it

>e thickness of grassing is 9 inches when finished, it will be laid

layers : the first, not exceeding one-third of the whole thickness,

ttrpot or khassa, or other coarse grass ; and it may be in the first

loose on the roof and tied tightly down with bamboo battens, not

aches asunder, with ties at not greater intervals than 9 inches.

' third coats to be always of thatching grass, made np into tatties

each of thickness sufficient to form one- third of the finished

ss is to be closely packed and tied with two bamboo battens

ove, and with ties at intervals not greater than 18 inches, each

be separately laid and tightly tied on to the roof, with ties at

tls than 9 inches. The whole surface of the finished roof

it rises or hollows.

ess of grassing is to be 6 inches, or 3 inches, it must be
or in one layer of thatching grass, laid, as specified above

ffl

*e to be of the full thickness of the grass coating, evenly
3 squarely neatly and perfectly straight
of a top coat has to be executed, the old top coat will

1KB. 2 H

222

SPECIFICATIONS FOR ROOF COVERINGS.

be entirely removed. All hollows will be made up evenly with fresh gran laid
under the battens of the lower coat, to which new ties, wherever required, will
be given, and the top coat of new grass will then be laid on as above, and sew
eaves' bandies given of the fall thickness of the grass roofing.
(/). — Petty repairs of grass roofs will consist of new grass passed into the old top
coating to cover any bamboos that may have become exposed, or to stop leaks ;
in renewing ties, where loose or decayed, and in replacing single battens when
these have become displaced,
(y;.— In renewing the whole or any portion of a roof, the serviceable grass tod
bamboos are to be carefully selected and tied in bundles, of size similar to those
of new grass.
(A). — Where a new grass roof or renewal of old grass, or of top coat of grass, has
to be executed, the whole of the ridge and hips shall be neatly bound over with
sirki matting, securely tied down over a roll of grass,
(i).— The following precautions must be strictly attended to in executing thatching:—
1. — A piece of ground is to be pointed out by the Executive Engineer, the dis-
tance from the nearest thatched building not to exceed 200 yards ; here a
work-yard will be established, and all straw and materials required for As
works will be deposited.
2. — The straw will be made up into tatties and bundles at this yard, and will

be carried to the building as it is required.
3. — In stripping a roof, the grass fit to be used is to be tied in bundles, and im-
mediately removed to the work- yards ; the refuse grass, as it is collected, is to
be carted away at once. Towards sunset on each day, if there be any grass
remaining near the building, it is to be taken back to the work-yard, and all
grass, whether new or old, is to be cleared away from near the building before
the workpeople are allowed to leave.
4. — A chowkeedar muHt be appointed in charge of the yard, who is to take pro-
per precautions to guard against fire ; he must also conform to any rules that
may be published by the authorities in cantonments.
(*).— Rope ladders are to be fixed to the ridge of all thatched roof coverings, and
are to lie on the slope of the roof to the eaves. The side ropes are to be of
closely twisted 5 inch circumference mfinj rope, and the rings are to be of pieces
of bamboo, 2 feet long passed through the strands at 2 feet intervals, and lashed.

Allahabad Single and Double Tiling,

o
o

2
4

LABOR.

Description.

Rate.

Oortof
Labor.

Masons, • .
Coolies, • .
Head mistree,

Carried over,

-/8/-
./86

• •

B8.
1
0

0
14

0
0
(

no
no

Materials.

Description.

BaU.

Coat of
Material*

Total R*
of Wort.

Flat tiles, (per

lot*) •

Half round tiles
(per°/ooi).-

Carried over,

87/-/-
36/-/-

RS.

A.
1

315

8 0

P.
1
4

SPECIFICATIONS FOB BDOP COVBB1NGS.

Bhteatf,
Profit to (

RS. A
2 ]
0 1
0 8

DacrlptloD. BiM

Brought ore

(per •/„„.) .
Ventilatir.
tiles,(per°U
Concrete fill in

(f'W ■

Total cost of

single tiled
rooting, p

100 b. ft,

Total co!
double tiled
roofing, p
100 s. ft.,

Country Tiling on 6' Thatch.

Grammy,

Coolie,

Bheeaty,

si 6* thatch, as per
detail,
500 Tiles,..

TOUI CO!

materials per
100 a. ft.,

Country Tiltt, on Matting,

Grain m its, ..

-m-

1,000

-ia|.

Bheeatv,

-ttf-

(

Profit to Con-

tractor, ..

lUaf.

Total cost ol

labor per 10(

(

) Tiles.

ng,(pe
und.) .
Bamboos,
• Matting,

Total coat ol

! 00 sit. roof-
ing,

iPEuiriCATiosB for roof coverings.

Corrugated Galvanised Iron Slutting.

LiBua.

MATSRIilJ.

°—

Bate.

CMtOf

Later.

"Ql Dwcfiplluu.

"**■ Uatsiak.

Total Rati

of Wari.

Smiths rivet-

= Weight of
-16/- 100B.ft.iron.

HS.

Lr.

-8)- =A*ddedfoi

•i

Smiths fixing,

Coolies „ ..

Carpenter, ,.

-J3I- Cirt. v a*.
-,'fi'l- = 2 0 i at

Hud raistj-ee,

■/12/- percent., ..

Bopesf scaffold

Carnage of do.

Rivets, iron,. .

■G-

Profit to Con

Washera, iron,

39.

Clips and no ts,

-.<■.!-

-■6.'6

;

White lead, . .

Total coet of
tabor per 100

eft.,

Bottle oi), . .
= 10' x 2' X

■A' wind ties,
<= t bolta, |'

diameter, ..

Total cost of
materials per

100 s. ft, ..

Total coat o

-/12/-

wg,

JVf ud on Reeds and files.

: 6/e/-

0 8 0
118 0

IW\

Total coat of
100a. ft roof-

SPECIFICATIONS FOR ROOF COVERINGS. 225

Mud on Reeds and Malting.

Total CO'
materials per

100 B. ft.,..

as.

0
8
8

0
0
0

C<rpeni«r«
squaring bhi

-m-

Caip*nteiH for
putting thin-

gles on roof 1

Coolie*,

Smith,
Coolie attend-

-i8|-

ing smith, . .

-»|.

Head mistrec

-M»l-

Profit to Con-

Total coat of
labor per 100

». ft.,

■PEC IF I CAT 1 0N6 FOB WOOF COVERINGS.

Slating.

LiHOX.

■tATKRULa.

—

«.

CMtof

— "

Cortirf
Malarial*.

Tunis*

OlW«t

Dressing alat-

220

-16/-

Slates 24' x
12% per 100

ISfRf-

BS.

tr.

Cooliea,
Head rairtree,

■ 1216 220
-12/-

Ropea, baskets

■w-

Bering boles,

-/*/"

&c,

(

Profit to Con

tractor, . ,

Total coat of
labor per 100
a. ft,

Total coat of

material a per
100 a. ft, ..

Total coat of

100 a. f tree-

ing.

ZYfed and Terraced.

Mason s setting
tiles,

I Bheeety,
I Head mist
Grinding it

Hoda, baik

Flat tiloa,
x e' :

Concrete,
White ltn

Siirki,
Whilewai
Mod be

T.kin'f

Total coat of
labor per 100

a. ft,

Total eoi
100 a. f

■PKCincATiODB roR roof covrhimgs.
Thatch, 9", 6" and 3*.

ill

G run mica,
Coolies, . .
Profit to a

Total coat of

labor per 100
•.ft.,..

Grammies, ,
Coolie*,.. .
Profit to Con

Total cob .
labor per 100
(.ft,..

(

0
0

Grammea pat-
ting on new,
Coolie, .. .,
G raminio r e -
pairing old,
Profit to Con-
Total cost of
labor pet 100
a. ft,,..

Total cos
materials pel
100 b. ft, .

Total coat •
100 b. ft 9'
thatching, . .
6* Thatching.

Bundle
grass,..

Bamboos,
■ String, ..
- Matting,

. sjgf-

.-;wr

Total eos
100 s. ft. 6'
thatching, .
3* Thatching.

Total cost of
100 8. ft 3-

thatching,.

SPECIFICATIONS FOR ROOF COVERINGS.

Thatch 9*, 6* and 3"— (Continued.)

UMft.

IUtibiils.

i
I

Docriptlon.

KU«.

8 .
5 5

Description.

HmW.

£Z&.

Total Bill

Ifate. — The above rates include the following cort of framework
and matting, which is to be deducted when they ere not given.

■

Grammy,

Total, ..

-fl-

RS
0

4
i

l]jn.
24
LOOtf.

BnmboM,
Matting,

Total, ..

a/e/- 9

2I-J- 0
-/10/. 0

Total amount
to be dedact-

EXPERIMENTS ON STRENGTH OF INDIAN CEMENTS. 229

No. cxcvni.

EXPERIMENTS ON STRENGTH OP INDIAN CEMENTS.

Extract from letter from P. Dejoux, Esq., C.E., Exec. Engineer,
Cement Experiments Division.

Dated Sealdak, 6th Feb^ 1875.

Portland Cement to be manufactured in Calcutta.— With re-
ference to orders received requiring a certain quantity of cement for trial
on a larger scale, I have been going on (with the present limited means
at my disposal) with its manufacture.

I had in stock 17 casks, of which three have been sent to the North-
Western Provinces, and one to the Exec. Engineer, 3rd Calcutta Division.

The annexed Statement A. shows further results obtained from test of
the Portland Cement manufactured by me.

It will be seen therefrom, that the late samples Nos. 12, 15, 16, 17 and
18 afforded better results than those previously tested.

The reason for this change is, that before beginning the experiments
on cements, I analysed the water of the tank in my office compound, and
as I found it contained a feeble proportion of sulphate of lime, it was
used : but after the recent heavy rains, I traced a marked decrease in the
strength of the cement.

This led to a fresh analysis of the water, and the result showed that
the proportion of the sulphate of lime had increased very sensibly.

The cause for this deviation may be explained by considering that the
level of the water having been very low before the last heavy showers, the
bottom of the tank got much disturbed by them, and thus a notable quan-
tity of the sulphate of lime contained in the earth got dissolved in the
water.

VOL. Y. — SECOND SERIES. 2 I

230 EXPERIMENTS ON STRENGTH OF INDIAN CEMENTS.

The last mixture was therefore made with river water, and the quality
of the cement consequently improved very much thereby.

This point is worth particular notice in the manufacture of either Port-
land or Artificial Cement, for which the quality of the water used for
mixing raw materials must be carefully tested.

Margohi Cement. — Of 5,841 cubic feet of this cement manufactured
during last year, 3,147 were used on the Sone Weir at Dehree, which,
after being submitted to the heavy floods of the last rainy season, afforded
very good results, as reported lately by the Exec. Engineer of the Dehree
Division.

The appended Statement B. shows further tests of the cement lately
manufactured mixed with sand, and it is obvious that the tensile strength
of such samples as were made properly is increasing very steadily, and
that a very strong mortar can be obtained with this cement.

I need not here repeat that it is absolutely necessary to entrust the
manufacture of cement of this kind to the direct charge of a competent
manager with some chemical knowledge.

In fact, the manufacture of every kind of cement requires great care
and attention, and the constant test and analysis of raw materials is par-
ticularly obligatory, otherwise the consequences result in anything but
what is satisfactory.

EXPERIMENTS OH STRENGTH OF INDIA* OEUBVTS.

231

«s

< £

•cs

•8

o
^

ipiz} axvnbi aod

urn uo itappiajq
eaojoq papoddas

petuaanni
ompj 3*q*. joQjy

**qurax

o
o

■** s

OS
AH

&
9

■B

-5 »

-5

•**

•

**a

• *4

=3 |

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2 K

238 DRAINAGE OF MADRAS.

No. CXCIX.

DRAINAGE OF MADRAS.

[Vide Plates XXXTTT. and XXXIV.]

Report by W. Clark, Esq., M. Inst. C.R, Drainage Engineer of
Madras, to the Secy, to Government, D. P. W., Fori Saint Georp.

Madr+s, April 1S7S.

In November last I was honored with instructions from the Secretary
of State for India to proceed to Madras, for the purpose of laying oat
a scheme for the drainage of the town.

In conformity therewith I proceeded by the earliest opportunity, and
arrived in Madras on the 12th December, 1874. I now have the honor
to report the completion of my labors, and to forward the plans, sections
and estimates of the various works I propose should be executed, for
submission to Government.

During the years 1864-5, Major Tulloch, R.E., had very carefully
considered the whole question, and I have had the benefit of his report
and plans to aid me. This report is so full and complete on the various
physical peculiarities of the district, its general features and conditions,
that I need do little more than summarise what he has stated.

The town stands on a sandy plain, the lowest part being from 2 to
6 feet, and the highest 16 to 24 feet above mean sea level ; water is
found in all parts of it, a few feet above or below mean sea level.

The rainfall averages about 50 inches per annum, which falls almost
entirely during three months ; and of this 20 inches in one month is not
unusual. In fact the rain comes chiefly in the form of heavy storms at
intervals, rather than as light rain of considerable duration.

I have also had the benefit of information contained in Dr. Cornish's

1 '-"PHIP jo «aiv

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nomfdo;! mail

DEAINiOR OF HADBAH.

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DBA IRAQI OF MADRAS.

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DBAINAGB OF MADRAS. 241

Census Report, which gives more accurate data as to the number of Popu-
lation, Houses, &c, than existed in 1 865.

Since that period also, Madras has been provided with a water supply
which has an immediate and most important bearing on the subject pf
drainage ; the more abundant the use of water, the more perfectly is the
filth carried away in suspension in sewers.

Facilities for obtaining an abundance of this necessary of life leads to
its larger use for domestic purposes ; and the necessity for its more per-
fect removal thereafter becomes more urgent ; for in the absence of proper
drainage, not only is there a probability of larger absorption of fluid filth
by the subsoil of the town ; but evaporation, which is after all the princi-
pal means of removal from stagnant and inefficient drains, adds greatly
to the generation and spread of malarious influences.

The city, for Municipal purposes, has eight divisions, which, with the
number of inhabitants in each, and its area, is arranged as shown in the
tabular statement on pages 239 and 240.

No. 1 Division comprises the district of Boyapooram and Tondiarpett,
and lies to the northward of the Railway at its sea side terminus ; it is com-
prised between the sea on the east, and Cochrane's Canal on the south.

The southern portion of this area, about three-fourths of a square mile,
is thickly inhabited, and will eventually be included in the drainage scheme.

The 2nd and 3rd Divisions comprise the whole of the Black Town, and
the Fort St. George ; it extends from the Railway on the north, to the
river Gooum on the south ; from the sea on the east, to Gochrane's Canal
on the west.

These Divisions are about 1-65 square miles in area ; the population
amounts to 1,26,283 by the last Census Report.

The average number of population to the square mile is 98,732 in the
2nd, and 57,249 in the 3rd, Division, and the number of inhabitants to
each house averages 10, or about double the density of the most crowded
European cities.

The 4th Division is entirely a suburban district, and not included in
the Drainage Scheme.

The 5th Division area is about 2£ square miles ; for drainage purposes
it is divided into two, the first including Choolay, Pursewaukum and
Vepery. The second, New Town, Poodoopett, Gomeleeswaram and
Egmore— portions of this area are also densely populated, amounting to

242 DRAINAGE OF MADRAS.

1S-8 persons in the 'tiled ' class of houses, which are about three-fourths
of the entire number.

The 6th Division is suburban, and is not included in the Drainage
Scheme. '

The 7th Division includes Chintadripettah and Triplicate; this also
for drainage purposes is divided into two districts. The population here
averages from 7 to 8 persons in each house of the better class. Its area
is a little less than one and a half square miles.

The 8th Division comprises Saint Thom6, Royapett, and four other
villages ; of these Royapett is adjacent to Triplicane, and is included with
it in the drainage arrangements.

Saint Thome, which contains about one-half of the 41,482, constitu-
ting its entire population, is one square mile in area, — it is too distant to
be included in the general scheme of drainage ; but its topographical fea-
tures and proximity to the sea admit of a separate small scheme being
devised for its drainage; which will be discharged into the sea in two
places ; the estimate for this work is included with the other.

The rise and fall of the tide is about three feet, and I have assumed
that the mean sea level is that taken by Major De Haviland in 1821, as
6 feet 1 0 inches below the mark cut by him in a stone fixed in the escarp
of the North Ravelin of Fort St George.

The datum to which the levels are referred in the plans and sections
accompanying this Report, is assumed to be 20 feet below the mean sea
level, to avoid the use of + and — quantities.

The prevailing winds in Madras are supposed to cause the currents
observed on the coast. From February to October, winds varying from
South- West to South chiefly prevail, they cause a more or less southerly
littoral current, and continue nearly nine months in the year.

During the cold season, November to January inclusive, three months,
the wind comes from North and North- East, with a corresponding change
of the current, — this is of importance in connexion with the position of
the outfall which has been chosen for the drainage system into the sea.
This point is about two miles north of Black Town, it was selected bj
Major Tulloch for his drainage scheme, and I quite agree with his reasons
for its adoption ; it is at a sufficiently remote distance— about two miles
from Black Town — to prevent any apprehension of inconvenience.

The present drainage of Madras is entirely of a 'surface' character!

DRAINAGE OF MADRAS. 243

save where a few of the larger sewers near their outfalls have been cover-
ed over.

The smaller drains are usually about one foot square, constructed of
brickwork, one on each side of the street, these receive all the slops and
fluid filth of the houses, and conduct it to the main outfalls.

These are the Bea — the River Cooum, — and Cochrane's Canal, which is
a tributary of the Cooum.

As a sample of surface drainage, those who advocate that system may
here see a fair example ; a system of surface drainage which has doubtless
been the result of careful enquiry and expensive addition from time to
time daring many years. How utterly it fails to remove without nuisance
the matters discharged into it, will readily be admitted by any one who
will take the trouble to inspect the daily cleansing, and breathe the at-
mosphere then pervading the locality. These drains appear to be carefully
attended to by the Sanitary Officer and hie subordinates, but no amount
of attention can render, what are in most cases stagnant receptacles of
filth, otherwise than objectionable.

These drains also receive the rain water and conduct it to one or other
of the outlets above named, and it is only on such occasions as a heavy
storm that they are thoroughly scoured out, and for a brief period cease
to be a nuisance.

The very small elevation of a large portion of Madras above the mean
sea level, 6 to 8 feet only, and one and a half feet less at high water,
renders, the discharge of the sudden and violent tropical storms a matter
of some difficulty.

Flooding of the lower parts of the town is not uncommon, which it
would be impossible entirely to prevent, even if an expensive system of
underground culverts be provided for the purpose.

Very early in my enquiry I was led to determine the necessity for
omitting from the scheme any provision for storm water. The area of
the town is so large and the distances so great, that any attempt to deal
with it in the way of underground sewers would have entailed an expense
quite beyond the means of the town to execute, as judged by the assess-
ment value of the houses.

An additional reason for excluding the Btorm water arises from the im-
possibility of making any provision which shall entirely remove the incon-
venience of floods during the periods of storm.

244 DRAINAGE OF MADRAS.

The utmost that could be done within any reasonable cost, woold be
the construction of sewers to remove one quarter inch of rainfall per hoar ;
as however this amount is exceeded, one inch falling not unfrequently in
that period, it is evident on such occasions that the streets would be flood-
ed, and the benefit would then be confined, to the somewhat more rapid
removal of the flood water when the storm had subsided.

Whether this would warrant the increased expenditure is matter for
question ; there would be an undoubted advantage attending such an ar-
rangement in many ways ; the old surface drains would entirely'disappear ;
footpaths forming a marginal channel for conducting the surface water
into the nearest entrance grating, would add greatly to the appearance
of the streets, and the segregation of the pedestrian passengers would
facilitate traffic and personal safety ; but it would be a surface improve-
ment after all, not actually required for the removal of filth, and I bare,
therefore, in consideration of the greater cost, certainly three times, deci-
ded to exclude the surface drainage.

The covering in of the present surface drains would of itself be a great
improvement, but it would be accomplished at a cost of about six annas
per foot, or double that amount for two sides of the street ; seeing then
that there are 125 miles of street to be sewered, I have omitted to include
the cost (about 5 lakhs of rupees) from the estimate, because it is a sur-
face improvement, one to be dealt with after the more pressing drainage
arrangements are provided for.

It is however probable that when, as I propose, these surface drains
shall be kept for the sole purpose of conveying away the storm water,
that improvements may be made.

The principal outlet for the present drainage of Black Town is a large
sewer, which occupies the site of a former nullah, in what are now Um-
pherson and Davidson's streets, and a portion of Popham's Broadway;
both ends of the sewer are carried to the sea, the northernmost near Old
Jail Street at the north end of Black Town, the southern one near the
Fort. Into this sewer is poured all the fluid filth of about two-thirds
of Black Town, and its 1,26,000 inhabitants, here it stagnates till
eleven o'clock at night when both outlets are opened, with doubtless a
very necessary discharge of the filth, but with an amount of nuisance
which is spoken of by thoFe who are exposed to it with superlative dis-
gust. Various expedients have from time to time been devised, for less-

DRAINAGE OF MADRAS. 245

ening the evil, a ventilating shaft has been erected to permit the escape
of the stagnant abomination without result ; what is now called Kellie's
Column remains to indicate that attempt ; some years since a windmill
was erected to pomp out the sewage, but it did not remove the nuisance ;
and more recently a steam engine has been erected for the same purpose,
but it is not now in use ; the various papers placed at my disposal show
that for many years past, repeated attempts have been made to remove
this monster nuisance, but in the absence of a large and comprehensive
scheme for dealing with the whole question, the desired result has never
been realized, and the Black Town sewer is now as famous for its potency
as ever.

Several smaller sewers discharge into the sea, and the remaining por-
tion of Black Town is drained into Cochrane's Canal, which communicates
with the river Gooum ; and both are the subject of loud complaint from
those who reside within their influence.

By far the largest portion of storm water falling on the 27 miles of the
Municipal area finds its way into the river Gooum, and about one-half
the drainage in the dry season.

The outlet of this river to the sea is usually closed from February to
October, including the hot season. During this period the river is in
fact a tank, receiving about one-half of the fluid filth of the town.
Organic matter thus becomes mixed with brackish water, and produces the
inevitable result, an offensive smell and a more or less malarious atmos-
phere in its vicinity.

Moreover the level of the water in this shallow pool falls gradually to
about low water level of the sea, and a large surface of seething mud
highly charged with decomposing filth exposed to the action of the sun.

It is however quite a mistake to attribute to the great luminary any
of the evils which result ; his active influence is ever exerted for good.
Where filth exists, the effect of the chemical as well as the calorific rays
is to promote the purity of the atmosphere; and the most potent of the
poisons resulting from decomposing filth are found in those open but
stagnant drains and ditches where they seldom or never penetrate.

The last published Municipal Report is for 1871-2, which gives the
following table of death-rate in the Great Cities of India :—

Madras, •• .. .. •• 33*4 per mille.

Bombay, . • •• .. .. 25*0 „

VOL. V. — SECOND BBBIE8. 2 h

246 DRAINAGE OF MADRAS.

Calcutta,

• • •

Lahore,

• • •

Nagpore,

• • •

Delhi,

• • •

Agra, . .

• • •

Lucknow,

• • •

• •

23 7 per mille.
285

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• • • • 2**9 „

• • • • 41*3 „

• • • • «v '9 „

• • • • 25 6 „

Madras owes much to its proximity to the sea, and the purifying
influences of the sea breeze ; hut notwithstanding all this, its mortality
amounted to 18,215 persons, or 88*4 per thousand, while 40 per cent, of
this was due to Zymotic diseases, and there were thus 5,290 more deaths
than should have been, had no sanitary evils existed within its bound-
aries.

The death rate for Madras, obtained from the Sanitary Commissioner's
office, for the past four years is —

1871, •• •• •• •• •• 2o«Jt>

1872, .. .. .. .. .. 85*26

1878, •• •• •• •• •• 36*7

The drainage of other portions of the Town area, Chintadripett, Kom-
lasvarar Covil, and Pudapauk, dram into the Cooom.

Triplicane has two outlets to the sea, similar to the Gooum, much
smaller but even more potent.

Milapore and St. Thome' have another, these three small rivers are
shut off from the sea for about ten months of the year, for they are sooner
closed by the shifting sand at the shore, than the larger river, and the
stagnant pools they form are even more strongly impregnated with de-
composing matter causing an insufferable nuisance.

Beach Road, which is the evening resort of the European population,
is a fine road, extending uninterruptedly a distance of 4£ miles from Old
Jail Street to St. Thome'.

Here the cool evening breeze from the sea in its curative and invigora-
ting influence has won for it the term of ' Doctor.'

How thoroughly enjoyable is this evening drive, and its ameliorating
effect on the Indian climate, every one will be ready to admit ; but it has
this very modifying condition, it must be approached judiciously. A
drive along this 4| miles is not altogether pleasant or enjoyable ; at inter-
vals of one mile, from the starting point at Old Jail Street the sewer
abominations are felt. The two outlets of the Black Town sewer are

DRAINAGE 07 MADRAS. 247

first passed, then the Coonm which becomes very offensive when its
communication with the sea is cut off by the ' bar/ Then at intervals of
half a mile, come the three smaller channels or pools which are always,
according to my experience, most offensive.

Six stinks " all well defined/1 must completely mar what wonld other-
vise be almost unrivalled in Indian stations, as a place of healthful exer-
cise and recreation.

It is quite evident, I think, that the condition of the Cooum would be
immensely improved by keeping open the communication with the sea, so
as to admit a fresh supply of water with every flood tide, and thereby
dilute — and if the drainage works I now have the honor to propose be
carried out, — eventually and entirely remove the nuisance arising from its
present misuse.

The three smaller streams above alluded to will only be improved
when the sewage which now flows into them is entirely diverted into other
channels for disposal.

I am of opinion there would be but little difficulty in keeping open the
communication between the Cooum and the sea at all periods of the
yew ; and if this can be done, the river will then be at all times in the
best condition for receiving the surface drainage. I had the honor to
forward for submission to Government a memorandum on this subject,
which will be found at the end of this Eeport.

I may now generally describe the principles and operation of the scheme
which I have the honor to submit for the approval of Government.
It is intended to remove
lit. The fluid filth proceeding from houses and manufactories ;
2nd. The subsoil water, from those localities where it is found in

the soil near to the surface ;
3rd. The excreta of the population.
The fluid filth from houses comprises the cooking and bathing water,
urine, and slops of all kinds that can be removed in running water.

It does not include ashes, entrails of fish and fowls, bones, cow dung
or any solid substances which should be removed by the Conservancy
carts.

The quantity of this fluid filth, or ' house drainage9 is represented by
the water supply, which after having performed its various uses should be
removed by the sewers; and for the purposes of calculation, I have

248 DRAINAGE OF MADRAS.

assnmed thai the supply is 20 gallons per head of the population residing
in the divisions to which it is proposed the work should extend ; these are
given in a tabular form at pages 289 and 240.

The new source of supply to Madras is said to he capable of giving 40
gallons per head to the entire population ; a quantity I think not likely
to be required, but which provides a satisfactory reserve for periods of
drought.

The present consumption is said to be about 7 gallons per head ; it is
limited to this in consequence of there being, at present, but a small
number of houses supplied direct from the mains, for which an extra
charge is made; only a limited number of connections are allowed in each
street, so as to prevent any undue decrease of pressure.

In the comparatively few streets to which the pipes extend, the appli-
cations for connections are numerous ; and there appears to be no hesita-
tion about incurring the expense of laying on the water to their premises
by the owners in those favored localities; about 100 houses are so
connected.

The people, however, generally resort to the public fountains, and
carry the water to their houses ; how great a labor this is, will be best
seen when the aggregate amount is considered.

The total population of Madras at the time of the last Census, in 1871,
was 3,97,552 ; at the rate of one gallon per head the weight to be carried
is 1,774 tons; the distance of the fountains apart averages £ mile, one-
half this distance is therefore the maximum distance the weight is carried.
Seven gallons per head amounts to no less a quantity than 12,418 tons,
nearly all of which has to be carried to the houses of the people.

The water would doubtless be a far greater boon than at present, if
this amount of daily labor could be reduced, by a more extended means
of distribution.

I am informed that all the larger pipes necessary for an extended con-
sumption have already been laid ; what is now required would therefore be
confined chiefly to a longer length of the smaller pipes.

There can be no doubt, I think, that with increasing knowledge of the
use, and value of an abundant supply of water, some extension of the
pipe system will be made; and I have, as above stated, taken the usual
quantity of 20 gallons per head for the purpose of calculation.

The quantity of 20 gallons per head of the population is therefore the

DRAINAGE OF MADRAS. 249

quantity which the drainage system should remove and which comes
under the denomination of house drainage.

This consumption is not, however, uniform during the 24 hours, it is
greatest between the hours of 7 and 10 in the morning, and I hare as-
sumed that one-half or 10 gallons of the daily supply is used during six
hours.

The next item is the subsoil water; this varies, of course with the
various seasons, wet and dry, of the year. It is greatest during the peri-
odical rains, but it continues for a considerable period after their cessation,
varying with the character of the subsoil ; while sand parts with it readily,
clay retains it for a much longer period.

During the rainy season of the year, the quantity of subsoil water in
Madras will probably fully equal the amount of the water supply at 20
gallons per head, and this, as I have explained, will continue for a con-
siderable period after the rains have ceased. Under the head of subsoil
water, I propose therefore to provide for the removal of a quantity equal
to the water supply, 20 gallons per head, flowing away uniformly during
the 24 hours.

The last item to be received by the sewers, is the night soil and excreta
of the population. On this subject authorities are not agreed, and very
divergent are the opinions offered.

Various systems have been brought forward and have found advocates.
Among these are the Liernieur, dry earth, and charcoal systems— and
many other substances and methods have been used for obviating the
nuisance of its removal; while many are the objections urged to the
principle of the water carriage system in sewers. Without entering into
any long discussion of the subject, I would call attention to the fact, that
whether the night soil be admitted to the sewers or not, the cost of the
drainage system will not be effected one single rupee; the quantity to be
thus removed is so small compared with that the sewers are competent to
remove, that the small addition amounts practically to nothing.

With the exception of the Liernieur system (which is said to cost
about £2 per head of the population ; about three times the eost of the
entire drainage works I am about to propose) all the various methods
suggested for the disposal of this material involve the cost of carriage
and manual labor. Up to the present time, as far as I know, not one of
them has been successful in an economical point of view ; and an expense

250

DRAINAGE OF MADRAS.

is entailed on the community or company as the case may be, about eqoaj
to the cost of carriage and the substance with which it has been mixed j
Liernieur himself up to this time has not, I believe, been able to show
any financial results, though he has proved the possibility of removing
the substance by his apparatus.

Sewage irrigation has been for several years gradually extending ; by
the water carriage system, no further expense is required when the water
and proper drainage works are available ; the handling of the substance is
entirely unnecessary ; moreover it passes away at once without any stop-
page or detention, and is out of the limits of the populated area before
decomposition can take place.

The water carriage system will, I think, be readily admitted to be the
cheapest where water is available and abundant, as it should be in Madras,
if the pipes for its distribution are extended throughout the town.

This not being the case it is too much to expect that the native in-
habitants will carry an additional quantity of 20 lbs. per head (which
would be sufficient) or an additional 3,548 tons of water daily for this
purpose ; and the night soil will not to any great extent, under the pre-
sent state of the water supply, be put into the sewers.

I would, however, urge that every encouragement and facility be given
to those who are inclined to adopt this plan ; first, because it reduces the
necessity for a most disgusting occupation : also because it reduces an
inevitable nuisance; and lastly, because by sewage irrigation I believe it
will find its most profitable employment in increasing the productive
power of the soil, which is its proper and legitimate use.

I consider also that what in Bombay is known as the Halicore cess, s
separate and distinct tax paid for removing excreta from the houses, is t
legitimate source of revenue ; which those of the inhabitants who may
arrange for its removal by the use of the sewers, and a larger consumption
of water will entirely escape.

The arrangements which I have made include the following separate
and distinct areas for drainage : —

First.— North of the Railway.

Second. — Black Town.

l%ird.— The Fort.

J<burth. — Paraewalkam, Egmore and Foodoopettah.

fytK— Chintadripett

Sixth. — Triplicane, and

Seventh,— St Thom&

DRAINAGE OF MADRAS. 251

The first of these is the only portion to which my scheme in detail
bas not extended ; up to this time the levels are not taken, but it will be
comparatively easy for any one who may have charge of the work to do
this, as a brick sewer extending from the sea beach along Old Jail
Street, and capable of conveying its drainage in the quantity I have men-
tioned is provided. This sewer will also at once be available for draining
the Government buildings on the North side of, and adjacent to Old Jail
Street.

In the second or Black Town Division, there is a considerable variation
of surface ; there are two well defined ridges parallel to the sea shore
with the street known as Popham's Broadway in the valley between them ;
the level of this and several adjacent parallel streets is from 6 to 7 feet
only above mean sea level.

The ridge on the West is occupied by Salay, or Mint Street, and from
&\a ridge the drainage on the West side is into Cochrane* 8 Canal.

Along Umpherson and Davidson's Streets and a part of Popham's
Broadway, is the large sewer which occupies the site of an old stream, and
terminates at both ends in the sea.

Along Popham's Broadway it is intended to construct a brick sewer with

a fall of four feet per mile towards Old Jail Street, where it meets with

another brick sewer for draining Royapooram, extending from North

Beach Road along Old Jail Street.

From the junction at Popham's Broadway, it is still continued along

Old Jail Street to Mooiieappen Moodelly's Street, along which it is carried

to Peddoo Naick's Lane ; here it leaves the public thoroughfare and is

carried through Garden Land till it reaches Annapilly's Street, thence it

continues through Public Land, on which there is a Wood Bazaar, and

the Cobra Tank to Wall Tax Road.
Here it joins the Pumping Station which it is proposed to place on the

open apace of ground at the foot of the Elephant Gate Bridge and close

to the canal.
This point is nearly central to the area to be drained, and its adoption

insures the best available inclination to the sewers, while it avoids exces-

*ire depths.
The Southern portion of Black Town and the Fort, will be drained

into a brick sewer extending along the Wall Tax Road, to the Hospital

Gate Road, as far as Evening Bazaar Road ; here the brick sewer, which

252 DRAINAGE OF MADRAS.

is laid at an inclination of four feet per mile terminates, and a 12-inch
pipe is carried into the fort at an inclination of 1 in 625.

Grossing the fort ditch below the level of the water, it will be possible
to place a valve in the pipe (which will here be of iron) by which this
pipe can be flashed should occasion require.

The main sewer is carried from the Pumping Station by a 3-feet iron
syphon under the canal, through the People's Park, to Sydenham's Road,
at an inclination of two feet per mile.

Here it sends off a branch through Choolay Bazaar Road for a dis-
tance of 1,350 feet. It is then continued along Yijiavignaswarar Covil
Street by a double 15 -inch pipe, at an inclination of 1 in 700 up to Per-
ambore Barracks Road; from this point a single 15-inch pipe proceeds
along Yencatasabuthen Street, and a low swampy portion of land, which
is called Oday, and conveys away surface water in the wet season.

From this point it is carried along Condapah's Moodelly, High Road,
into Pursewalkum High Road at the same size and inclination. Here it
is reduced to 12 inches in diameter, and the inclination is made 1 in 600 ;
it terminates at Yenethetha Moodelly's Street.

From the Choolay Bazaar Road the Main sewer extends along Syden-
ham's Road to near Lawe's Bridge over the Cooum River, which is crossed
by an iron syphon two feet in diameter, laid below the bed of the stream
into Ghintadripettah ; here it enters Iyah Moodelly's Street which it
traverses its whole length to the Waller's Road ; it is then laid for a short
distance through Nursingapooram Parcherry, to the compound occupied
by Messrs. Taylor's Livery Stables which it crosses diagonally, and enters
Blacker's Road, along which it proceeds to Wallajah Road.

From this point a branch 12-inch pipe sewer is laid along Mount Road
at an inclination of 1 in 400 as far as Woods' Road.

The brick sewer is continued along Triplicane High Road, to the
Nabob's Palace ; across the compound of which a 15-inch pipe is laid
through Chellapilliar Covil Street to Pycroft's Road, and terminating at
Peter's Road, where it receives the sewage of Royapett.

In the Triplicane High Road, the brick sewer is continued to the cross-
ing of Pycroft's Road ; from this point it is extended to Peter's Road by a
15-inch pipe. Another branch pipe is laid towards the East in Pycroft's
Road to Yencatarunga Pillay's Street. The whole of these main sewers
except where otherwise mentioned, have an inclination of four feet per mile.

DRAINAGE OF MADRAS. 253

One other branch remains to he described ; this extends from Syden-
ham's Road, along Poonamallee Road, to the East side of the Scotch
Church compound ; along which it is carried to Jordan's Road ; it is then
continued along this and Whannell's Boad, to Pantheon Road ; here the
brick sewer terminates, and a pipe 12 inches diameter is carried through
Lang's Garden Parcherry to Harris9 Road, at an inclination of 1 in 765.
From Jordan's Road a 9-inch pipe sewer is carried along male Asylum
Road to Egmore, at an inclination of 1 in 400.

I have thus described generally the position and particulars of size and
inclination of the main sewers ; they are all adapted to the work they have
to do, and are sufficient for the purpose; in most cases they are laid
below mean sea level, and will permanently receive subsoil water, even
when other portions of the system during the dry season of the year may
cease to do so.

The conditions under which they are placed will necessitate no especial
provision for flushing.

Deposit in sewers chiefly consists of road sand — the material of which
the road is composed when gronnd down by the action of wheeled vehicles ;
on the occurrence of the first shower of rain, this road sand is washed into
the sewer more or less according to the precautions taken to arrest it by
1 Gully Pits,' where the storm water is first received ; but however perfect
the action of these pits may be in arresting the heavier particles, a large
quantity is carried into the sewers ;— many hundred tons are thus washed
into the sewers of a town as large as Madras by a single shower, and ex-
pense is usually entailed when its removal by hand, is necessary.

For this purpose, the brick sewers were only a few years ago generally
constructed of brickwork, of a size to admit of the entrance of men for the
purpose of cleansing them, and without reference to the quantity of fluid
filth they have to remove ; sewers were thus frequently made too large for
the work they had to do. It is now well known that the more concentrated
the flow of any given stream, the greater is its power to keep itself clear
and free from deposit ; this led to the adoption of the oval shaped sewers,
where the invert is generally struck with a radius not exceeding that of *
pipe sewer, hence the oval brick sewer combines both advantages.

The only legitimate argument for making a sewer large enough
for a man to enter it, is for the purpose of making good the house con-
nections.

VOL. V.— SBCOND SERIES. 2 M

254 DRAINAGE OF MADRAS.

Bat in the scheme which I now propose, it is intended to exclude the
surface water, and this scource of deposit material is at once got rid of,
while of the household processes by which sandy material is produced,
probably that of scouring brass cooking utensils in this country is the only
one from which such deposit could occur.

There is, however, every reason why the cleansing of the sewera should
be provided for. When pipe sewers are laid in sandy soil, it is always
necessary to thoroughly cleanse them of the sand which unavoidably enters
the pipes during the process of laying, especially if it happens to be in wet
and difficult ground.

For the purpose of cleansing the pipes, my practice has been to lay
them in straight lines, and never on any account to depart from this rule.
At a distance not exceeding 800 feet, a ' manhole ' is constructed ; this is a
well extending from about one foot below the surface of ground, where it is
covered by an iron cover, to the depth of the sewer ; it is usually of oval
from three feet six inches long, by two feet in its greatest width ; it is suffi-
ciently large for a man to enter ; if the pipe sewer is clean he is able
to see light at the other end, as a perfect circle; if it be obstructed, a
split bamboo with a small line attached can be forced through to the next
manhole, this is made to draw a light chain with a circular iron scraper
made for the purpose.

If then there be any quantity of water running through the pipe, by the
help of the agitation caused by drawing the chain back and forward, it is
speedily removed and carried down the pipe to the next manhole.

All pipe sewers are thus easily cleansed if necessary. If the pipes be
properly laid and all entrances to house drains trapped by syphon traps,
as they should be, it becomes exceedingly difficult to put anything into the
sewers which will stop them.

As the same velocity can be obtained by a given quantity of fluid in a
pipe as in a brick sewer, and if the pipe be of sufficient size to do the
work required of it, it is manifestly more desirable to put down the
cheaper small pipe, than an unnecessarily large brick sewer, and this
principle has guided me in laying out the main sewers which I have above
described.

In the arrangement of the smaller pipes, the same principle has been
followed, save that when the quantity of fluid to be passed through a pipe
is very small, it becomes necessary to assist its self-cleansing action by a

DRAINAGE OF MADRAS. 255

better gradient, thus the smaller pipes have better falls than the larger
into which they discharge.

In the present scheme no 6-inch pipe, which comprises five-sixths of
the whole, has a smaller gradient that 1 in 800, or something more than
17 feet per mile, and many of them much more than this.

Manholes, such as I have described, at every 200 to 800 feet, are also
constructed at every junction of one street sewer with another ; in these
cases the floor of the manhole is formed by brick in cement into a sort of
half pipe channel, having the effect of a curved junction. It is also desi-
rable at all junctions of pipe sewers, to give the tributary pipe a fall of
from one to three inches to accelerate, rather than retard the main stream.
When, owing to the tortuous windings of a lane, the manholes would
be very close together. Lamp holes are adopted in their place alternately
with the manholes. These are considerably cheaper, being from 9 to 14
inches square only. A lamp suspended in them enables a person in the
adjacent manholes to ascertain if the pipe be clear, and if not, the posi-
tion of the obstruction ; all these are provided for in the Estimate.

From what I have said in page 248, the quantity of fluid to be passed
through the sewers will be at the rate of 20 gallons per head of the popu-
lation; and half of this or 10 gallons will enter the sewers in six hours.

To this must be added the subsoil water equal to 20 gallons flowing in
uniformly during the 24 hours, or at the rate of five gallons in six hours.
Thus 15 gallons in six hours may be considered as the maximum flow for
each unit, and 15,000 gallons per 1,000 of the population. This quantity
is 41 '66, say 42 gallons per minute.

In Black Town, an examination of the Revenue Survey shows that the
holdings average 80 feet of frontage.

The number of persons residing in each of these is greatest in the 6th
Division, where 18 persons reside in ' Terraced Houses/ there however
this description of house is not numerous, the ' Tiled House ' are more
than double the number, and in these 6*7 is the average.

In Black Town the greatest number also reside in Tiled Houses, and
the average is 10*8 ; but taking 10 as the average for all houses, then
there will be 10 persons residing on every 80 lineal feet of the street on
one aide, or double the number on both sides ; this amounts to 20 per-
sons on every 80 feet, or 2,852 persons per mile ; if therefore 2*852 be
multiplied by 42, it will give the quantity, 120 gallons per minute.

254 DRAINAGE OF MADRAS.

Bat in the scheme which I now propose, it is intended to exclude the
surface water, and this scoarce of deposit material is at once got rid of,
while of the household processes by which sandy material is produced,
probably that of scouring brass cooking utensils in this country is the only
one from which such deposit could occur.

There is, however, every reason why the cleansing of the sewers should
be provided for. When pipe sewers are laid in sandy soil, it is always
necessary to thoroughly cleanse them of the sand which unavoidably enters
the pipes during the process of laying, especially if it happens to be in wet
and difficult ground.

For the purpose of cleansing the pipes, my practice has been to lay
them in straight lines, and never on any account to depart from this rule.
At a distance not exceeding 300 feet, a ' manhole ' is constructed ; this is a
well extending from about one foot below the surface of ground, where it is
covered by an iron cover, to the depth of the sewer ; it is usually of oval
from three feet six inches long, by two feet in its greatest width ; it is suffi-
ciently large for a man to enter ; if the pipe sewer is clean he is able
to see light at the other end, as a perfect circle; if it be obstructed, a
split bamboo with a small line attached can be forced through to the next
manhole, this is made to draw a light chain with a circular iron scraper
made for the purpose.

DRAINAGE OF MADRAS. 255

better gradient, thus the smaller pipes have better falls than the larger
into which they discharge.

In the present scheme no 6-inch pipe, which comprises five-sixths of
the whole, has a smaller gradient that 1 in 800, or something more than
17 feet per mile, and many of them much more than this.

When, owing to the tortuous windings of a lane, the manholes would
be very close together. Lamp holes are adopted in their place alternately
with the manholes. These are considerably cheaper, being from 9 to 14
inches square only. A lamp suspended in them enables a person in the
adjacent manholes to ascertain if the pipe be clear, and if not, the posi-
tion of the obstruction ; all these are provided for in the Estimate.

To this must be added the subsoil water equal to 20 gallons flowing in
aniformly during the 24 hours, or at the rate of five gallons in six hours.
Thus 15 gallons in six hours may be considered as the maximum flow for
each unit, and 15,000 gallons per 1,000 of the population. This quantity
is 41*66, say 42 gallons per minute.

In Black Town, an examination of the Revenue Survey shows that the
holdings average 80 feet of frontage.

The number of persons residing in each of these is greatest in the 6th
Division, where 18 persons reside in * Terraced Houses,9 there however
this description of house is not numerous, the ' Tiled House ' are more
than double the number, and in these 6*7 is the average.

In Black Town the greatest number also reside in Tiled Houses, and
the average is 10*8 ; but taking 10 as the average for all houses, then
there will be 10 persons residing on every 80 lineal feet of the street on
one side, or double the number on both sides ; this amounts to 20 per-
sons on every 80 feet, or 2,852 persons per mile ; if therefore 2*852 be
multiplied by 42, it will give the quantity, 120 gallons per minute.

254 DRAINAGE OF VADRAS.

Bat in the scheme which I now propose, it is intended to exclude the
surface water, and this sconrce of deposit material is at once got rid of,
while of the household processes by which sandy material is produced,
probably that of scouring brass cooking utensils in this country is the only
one from which such deposit could occur.

For the purpose of cleansing the pipes, my practice has been to lay
them in straight lines, and never on any account to depart from this role.
At a distance not exceeding 300 feet, a * manhole ' is constructed ; this is a
well extending from about one foot below the surface of ground, where it is
covered by an iron cover, to the depth of the sewer ; it is usually of oval
from three feet six inches long, by two feet in its greatest width ; it is suffi-
ciently large for a man to enter; if the pipe sewer is clean he is able
to see light at the other end, as a perfect circle; if it be obstructed, a
split bamboo with a small line attached can be forced through to the next
manhole, this is made to draw a light chain with a circular iron scraper
made for the purpose.

In the arrangement of the smaller pipes, the same principle has been
followed, save that when the quantity of fluid to be passed through a pip*
is very small, it becomes necessary to assist its self-cleansing action by a

DRAINAGE OF MADRAS. 255

better gradient, thus the smaller pipes have better falls than the larger
into which they discharge.

In the present Bcheme no 6-inch pipe, which comprises five-sixths of
the whole, has a smaller gradient that 1 in 300, or something more than
17 feet per mile, and many of them much more than this.

Manholes, such as I have described, at every 200 to 300 feet, are also
constructed at every junction of one street sewer with another ; in these
cases the floor of the manhole is formed by brick in cement into a sort of
half pipe channel, having the effect of a curved junction. It is also desi-
rable at all junctions of pipe sewers, to give the tributary pipe a fall of
from one to three inches to accelerate, rather than retard the main stream.

From what 1 have said in page 248, the quantity of fluid to be passed
through the sewers will be at the rate of 20 gallons per head of the popu-
lation; and half of this or 10 gallons will enter the sewers in six hours.

To this mast be added the subsoil water equal to 20 gallons flowing in
uniformly daring the 24 hours, or at the rate of five gallons in six hours.
Thus 15 gallons in six hours may be considered as the maximum flow for
each unit, and 15,000 gallons per 1,000 of the population. This quantity
is 41*66, say 42 gallons per minute.

In Black Town, an examination of the Revenue Survey shows that the
holdings average 30 feet of frontage.

The number of persons residing in each of these is greatest in the 6th
Division, where 13 persons reside in ' Terraced Houses,' there however
this description of house is not numerous, the ' Tiled House ' are more
than double the number, and in these 6*7 is the average.

In Black Town the greatest number also reside in Tiled Houses, and
the average is 10*3 ; but taking 10 as the average for all houses, then
there will be 10 persons residing on every 30 lineal feet of the street on
one side, or double the number on both sides ; this amounts to 20 per-
sons on every 80 feet, or 2,852 persons per mile; if therefore 2*852 be
multiplied by 42, it will give the quantity, 120 gallons per minute.

254 DRAINAGE OF MADRAS.

For the purpose of cleansing the pipes, my practice has been to lay
them in straight lines, and never on any account to depart from this rule.
At a distance not exceeding 300 feet, a * manhole ' is constructed ; this is a
well extending from about one foot below the surface of ground, where it is
covered by an iron cover, to the depth of the sewer ; it is usually of oral
from three feet six inches long, by two feet in its greatest width ; it is suffi-
ciently large for a man to enter ; if the pipe sewer is clean he is able
to 6ee light at the other end, as a perfect circle; if it be obstructed, a
split bamboo with a small line attached can be forced through to the next
manhole, this is made to draw a light chain with a circular iron scraper
made for the purpose.

All pipe sewers are thus easily cleansed if necessary. If the pipes be
properly laid and all entrances to house drains trapped by syphon traps,
aa they should be, it becomes exceedingly difficult to put anything into the
sewers which will stop them.

DBAINAGB Of MADRAS. 255

better gradient, thus the smaller pipes have better falls than the larger
into which they discharge.

In the present scheme no 6 -inch pipe, which comprises five-sixths of
the whole, has a smaller gradient that 1 in 800, or something more than
17 feet per mile, and many of them mnch more than this.

To this must be added the subsoil water equal to 20 gallons flowing in
miformly during the 24 hours, or at the rate of five gallons in six hours.
Thns 15 gallons in six hours may be considered as the maximum flow for
each unit, and 15,000 gallons per 1,000 of the population. This quantity
» 41-66, say 42 gallons per minute.

In Black Town, an examination of the Revenue Survey shows that the
holdings average 80 feet of frontage.

The number of persons residing in each of these is greatest in the 6th
Division, where 18 persons reside in ' Terraced Houses,' there however
this description of house is not numerous, the ' Tiled House ' are more
than double the number, and in these 6*7 is the average.

In Black Town the greatest number also reside in Tiled Houses, and
the average is 10*8 ; but taking 10 as the average for all houses, then
there will be 10 persons residing on every 80 lineal feet of the street on
one side, or double the number on both sides ; this amounts to 20 per-
sons on every 80 feet, or 2,852 persons per mile ; if therefore 2*852 be
multiplied by 42, it will give the quantity, 120 gallons per minute.

256 DBAINAGE OF MADRAS*

Now a 6-incn pipe sewer laid with a gradient of 1 in 300 will discharge
134 gallons per minute. It is evident therefore that in Black Town a 6-
inch pipe may be laid so as to receive the drainage of one mile of houses.
In no case however has this limit been approached in the present scheme,
and ample provision is therefore made for the maximum flow of drainage
fluid as above calculated*

Similarly all the large sizes are determined, and a margin left for even
in increased flow.

There is much reason to fear that the. quantity to be carried away will
J>e much less than what is shown above, until the water supply is farther
extended.

The larger the quantity of fluid flowing within their capacity, the more
perfect the action of the sewers.

The pipes are laid as before described in perfectly straight lines, they are
bedded in concrete to prevent unequal settlement, and preserve the accuracy
of the line both vertically and horizontally. Regularity of shape and
perfect lines and levels are both necessary to success, and both are
attainable.

The pipe joints are made with Portland cement for three parts of the
circumference, the remaining one-fourth at the top is packed with well
tempered clay and covered with concrete. This prevents the entrance of
sand, but permits small quantities of subsoil water to pass in at the top
of the pipe, and thus the subsoil drainage is effected.

It is well nigh impossible to make brick sewers water-tight, when they
are laid, as they will be here, beneath the permanent level of saturation ;
most bricks are so porous that the water passes through them. It is
however, usual to put an agricultural drain pipe through the side wall of
the sewer at intervals of 50 feet above the general line of flow ; this ter-
minates in a lump of broken bricks on the outside, it admits the subsoil
water, and excludes the sand, and by this means also the subsoil drain-
age is effected.

It may be, that owing to the intrusion of some semi-fluid substance
flushing may be necessary ; one cause of this I have found in semi-fluid
cow-dung, which the cow-keepqrs thus endeavour to dispose of, when they
are unable to dry and sell it, in the wet season.

For flashing, the manholes are a great assistance, Some temporary
expedient such as a ship's ( swab ' may be jammed in front of the pipes so

PLATE XXXIV.

DRAINAGE OF MADRAS. 257

m to prevent the water from escaping ; if the manhole then be filled with
water by a hose from a neighbouring water main, and the stoppage of the
line requiring to be cleansed is suddenly removed, a considerable body, 40
or 50 cubic feet of water may be forced through the pipe and wash it out
completely.

When constructing brick sewers in ground saturated with water, it is
usual to first lay a drain pipe in concrete, a few inches below the level of
the sewer ; this collects the water from the subsoil, and it is pumped out
from small wells or * sumps ' at intervals ; this plan enables the construc-
tion of the brickwork to be more satisfactorily accomplished than it could
otherwise be, and notwithstanding the cost of the drain pipe, it is the most
economical mode of proceeding. It also enables the coating of cement
plaster to be laid on the surface of the bricks, which, if the cement be
good, is impervious to water; it prevents their absorbing the sewage, and
gives a smooth surface to the channel. This cannot possibly be accom-
plished unless the sewer be kept free from water.

Cement plaster for the interior of the sewers is provided in the
Estimate.

After the sewer is completed, it is usual to fill up the wells or sumps
with concrete, and exclude the subsoil water ; I have, however, in a few
cases left a small space to be filled with agricultural drain pipes placed
vertically so as to admit the subsoil water to rise into the sewer from the
drain pipe ; where these are left, however, there should always be a greater
pressure of water tending to enter the sewer, than is due to the depth of
the ordinary flow favoring its escape.

Where the sewer is constructed at any considerable depth — four or five
feet below the level of saturation — this will usually be the case, and in such
cases small fountains remain permanently, and are most useful in keeping
the sewer clean, while the subsoil drainage is also provided for.

The ventilation of the sewers will be effected by gratings fixed in the
road surface near to the manholes and in connexion with them at dis-
tance of about 100 feet, these are provided for in the Estimate and shown
in the drawings,

I have now generally described the positions and the action of the main
and pipe sewers for conveying the sewage to the Pumping Station, which,
as I have before mentioned, I propose should be constructed near the Ele-
phant Gate Bridge.

258 DRAINAGE OF MADRAS.

Three main sewers, viz., from Royapooram and north side of Black
Town, — the second from the south end of Black Town and the Fort; and
the third from People's Park, which receives all the drainage of Pune-
wanknm, Cbintadripettah and Triplicane. All these will be received into
a well 30 feet in diameter, at the Pumping Station, This well will be
snnk 10 feet below the level of the sewers, and the inverts of these will
be 8 feet below mean sea level.

The work required to be done by the engine will be as follows : —

The total population living on the drained area will be (as per Table,
page 240,) 2,96,904 ; 8,00,000 may be taken for calculation.

The maximum quantity of house and subsoil drainage may be taken
at 42 gallons per minute per 1,000 of the population, page 255.

then 800 x 10 lbs. x 42 gallons = 1,26,000 lbs.
and the lift will be 19*5

680000
1184000
126000

2,457,000*0 foot lbs. par minute.

2,457,000 -A .
^^«70.h«epower.

When the works are fully completed, the working of 70-horse power
effective, will be required during six hours of the day.

This power must be supplemented by one-half more, or 105-hone
power effective, in the aggregate.

For the present, two engines of 85-horse power effective, will be am-
ply sufficient, and the cost of these and the engine house, &c., to con-
tain them is provided in the Estimate.

The engines and pumps I propose to erect will be precisely similar to
those which in Calcutta have proved successful, with such improvements
as experience since their erection has suggested.

The principal feature of these combined engines and centrifugal pumps,
is a large cast-iron cylinder, extending from a little above the invert
level of the sewers, to the top of the outlet culvert ; in this case it will
be 20 feet high, by 8 feet diameter.

On this cylinder the engines, and A frames, carrying the driving wheel
are supported ; and the vertical shaft and centrifugal pump disc are sus-
pended.

DRAINAGE OF MADRAS. 259

The suction pipes extend from the bottom of this cylinder to a low level
in the pump well.

The pump disc is formed of two circular metal plates, with a circular
hole in the centre. The two plates are kept apart by curved division
pieces extending from the circular hole to the periphery of the disc, which
is open.

The disc is attached to the end of the vertical shaft at its lower end,
and when in place, is at the bottom of the vertical iron cylinder.

The suction pipes are so arranged as to carry the sewage to the cir-
cular hole in the disc which is made to revolve with great rapidity.

This motion causes the sewage to be thrown out of the disc at its peri-
phery, as it continues to enter at the circular hole at the centre, and with
the force necessary to insure its rising in the iron cylinder to the required
height above the invert of the outfall culvert. The outlet pipe from the
cylinder leaves it at a higher level, and thence the sewage flows to its
outfall.

In the present case, the top of the cylinder will be somewhat higher
than the top of the outfall culvert in Mint Street, and the connecting
channel between them will be an iron pipe three feet six inches in diameter,
laid in Rawmanen Street ; up this pipe the sewage will be forced into
the outfall culvert by attaining a sufficient height in the pump-cylinder*

I have thus endeavoured to describe the pumping operation in order to
show that it can be so arranged as to prevent any nuisance from arising.

The pump well will be entirely closed from the outer atmosphere, but
a flue will be constructed from it to the boiler furnaces, the pump well
will be thus ventilated, and the gas consumed by the engine furnaces.

The suction pipes are of iron, air tight in their connection with the
cylinder, the top of the cylinder is also closely covered ; it is evident there-
fore that the sewage is not in any way exposed to the air during the pro-
cess of pumping, and there can be no escape of gas and no nuisance.

An apparatus consisting of an air blowing cylinder will be attached to
each engine and iron pipes to convey compressed air to the pump well,
this pipe terminates in an open perforated pipe laid on the bottom of the
well* The use of this is to agitate the sludge or semi-fluid which may
accumulate in the well, and mix it up with the more fluid sewage, and so
dilate it as to permit its being pumped away, thereby obviating all neces-
sity lor manual labor in cleansing the well.

2G0 DRAINAGE OF MADRAS,

This arrangement baa been perfect] j successful in Calcutta, where fre-
quently a quantity equal to 600 tons of solid in tbe form of road grit is
disposed of in about four hours.

A culvert to convey water from the canal, when required for the pur-
pose, will be provided.

The outlet pipe from the pumps, will as above stated, be 42 inches is
diameter, of cast-iron, it will be laid along Rawmanen Street as far is
Mint Street which occupies the ridge of high ground above referred to,
page 251. It is of such a level as to admit of a brick culvert four feet nine
inches high being laid beneath the surface, with an inclination of five feet
per mile ; at its highest point where the iron pipe from the engines
joins it, its invert is 10 feet over mean sea level, or SO feet over datum.
The total fall in the outfall culvert will therefore be 10 feet, which is thus

distributed.

8,170 feet 4'-9* X 4*0 oval culvert, fall 5 feet per mile.
12,536 „ 6'-0' X 4-6 „ „ „ 2 „ „

8,866 „ open excavation with walling at bottom 4 feet ; fall 1 in 3,040.

The open excavation is carried through market gardens, and waste
land to the sea.

At the sea end, a length of 200 feet of 5'*9' X 5'-0v oval brick culrert
will be constructed with a further length of 22 feet of stone masonry work
in which the junction lengths of a 4'-6* cast-iron pipe will be firm)/
secured at the margin of the sea. This four feet six inch pipe will be
continued into the sea for a distance of 100 feet, supported on screw pile
jetty work.

At the end of the pipe a valve is arranged to close by a float, the
object of this is to prevent sea water entering the pipe, while the sewage
is allowed to escape freely. The level of the pipe is one foot above mean
sea level.

The point chosen for the discharge of the sewage into the sea is two
miles to the north of Old Jail Street, there are no habitations near, and
along the line of the open excavation, it is equally removed from residences
of the population.

This open portion of the outfall channel can also be made in the form
of a brick culvert, of course at some increase of cost, but I have consider-
ed desirable that it should be constructed as an open channel, and ererj
facility given to the market gardeners on the line to irrigate their gardens
with the sewage ; there is no doubt whatever of the result.

DRAINAGE OF MADRAS. 261

The fertilizing value of sewage being thus illustrated, it is to be hoped
that some capitalists may be found to take up the question of the utiliza-
tion of the entire sewage of Madras, any of the waste land lying at a level
not higher than 8 or 9 feet over mean sea level, and within a distance of
five or six miles of Madras may be irrigated with the sewage without
further pumping.

There is an enormous area of low land, in the direction of the canal
which may thus be fertilized Much of it would however, require special
works for its drainage, but even this will not be too expensive an opera-
tion to exclude its use.

Of all the various schemes which have been adopted for the disposal
and utilization of sewage, irrigation is the one which has, according to my
experience, proved remunerative, which requires no manipulating or
manufacturing process, always expensive, previous to use ; and which is
most readily applied. Sewage farms in the neighbourhood of London and
other large Towns in England, are rapidly increasing with promise of
great Buccess.

In England the one great difficulty is the cost of keeping the land clear
of weeds, which grow as rapidly as the crops, this is a serious difficulty
in sewage farming. In India, however, where crops of equal value, sugar-
cane, tobacco, corn, garden vegetables, and the grasses grow under its
influence, most luxuriantly, the cost of manual labor is cheap, and the great
difficulty disappears.

Having had the management for a short time of a small sewage farm,
I can speak with great confidence on this question. It is too much to
expect that any profit can be immediately realized by the Municipality
out of sewage operations of this kind, but after the requisite experience
has been obtained, there can be no doubt whatever that capital may thus
be profitably employed, and the necessity for discharging the sewage, ex-
cept on rare occasions into the sea, be avoided.

Such is a general view of the drainage sheme I propose for considera-
tion of Government. I may now add a few ideas on the subject of
material.

I have throughout spoken of brick sewers, and the estimate has been
made for brickwork of a very superior kind ; but the bricks I have seen
in Madras are not well suited to this work, though well shaped, and
burned, they are too absorbent ; the material of which they are made is

VOL. V. — SEOOHB SERIES. 2 N

262 DRAINAGE OF MADRAS.

not good, and I have included in the estimate the cost of inside plastering
with cement, if this is properly done, it is like a coating of smooth stone,
and will remove the objection of absorption.

I have also provided for a large quantity of concrete in which the brick
sewers are to be embedded, this will very materially strengthen them, bat
it involves considerable expense.

It has occurred to me, and I have taken steps to enquire, as to the use
of laterite blocks for this purpose in substitution for brick sewers, to be
plastered with cement on the inner surface of the sewers.

The questions to be solved are, can this material be cut with sufficient
accuracy and to the required shape ? If so, will the cost be. less than that
of brickwork ? I have very little doubt that all these questions may be
answered in the affirmative, some blocks are now being cut of the required
shape, and the point may soon be settled.

The next question, will Portland Cement adhere to the laterite blocks
in the sewage ? this will take a longer time to answer, and I would pro-
pose that some of the blocks should be cemented and placed in one of the
sewers to ascertain if the adhesion of the cement continues perfect under
these circumstances ; I would advise the continuation of this inquiry.

Failing the use of laterite, concrete blocks may, I believe, be employed
with advantage, and almost equal economy.

So much of the material for these works requires to be of special form,
if brick be used, some considerable time must elapse before a commence-
ment can be made ; the sewers require almost exclusively bevelled bricks ;
the manholes wedge-formed bricks, and so on ; all this will take time to
prepare, but if laterite be used, this loss of time will be wholly avoided,
as I am informed there is an abundance of material within 12 miles of
Madras and labor to cut it.

The drain pipes to be used should be of the best quality procurable ;
India, according to my experience, though possessing the crude material,
has not at present produced pipes with the accuracy of shape required.
The best English pipes leave little to be desired in this way ; not only
must the pipes be good, but of even greater importance is the accuracy of
the workmanship required to lay them. Native workmen when carefully
instructed are quite competent to this ; and the considerable quantity of
concrete provided for in estimate on which to bed them will, I believe,
prevent sinkage and insure permanent and good lines.

DRAIWAGK OF MADRAS.

263

Probably most important to the efficient action of drainage scheme is
the House Drainage. This is usually left to ordinary workmen who may
or may not have the requisite skill and experience. The unanimous opi-
nion of all Sanitary Engineers I have met with, and it is decidedly my
own also, is that none but men who are experienced in the work should
be permitted to touch it; this of course necessitates the employment of a
department for the purpose ; where every man's work can be known, and
any failure traced to its proper source ; where work must be at once
covered up and remain unseen, it is too great a temptation for irrespon-
sible and often very ignorant men, to scamp it.

It may, and generally does happen, that on completing a house drain
pipe, a length is required to fill up an interval, not exactly two feet (the
manufactures' length) and another of the required length is not procurable ;
it is a material impossible to cut, the consequence is that a broken pipe is
put in and an open joint is left, through which the sewage can escape and
saturate the surrounding soil ; and which may also admit the earth and
cauBe a stoppage in the pipe.

There are innumerable ways in which the efficiency of a stoneware
pipe house drain can be impaired in its efficiency without actually fail-
ing ; the result may be, and often is, sickness in the household ; and from
such causes the bad workmanship of incompetent workmen, house drain-
age as a system is actually in some cases condemned as an evil rather
than a good ; every one who has experience in the subject will be able to
confirm what I have now stated, and as to the general inefficiency of the
work done by persons without the necessary especial experience.

I have spent many years in endeavouring to perfect the scheme of
drainage in Calcutta, but I entertain serious apprehensions that the good
which has been done will be very considerably diminished by the * free trade '
in house drainage which has been encouraged, notwithstanding my re-
peated remonstrances ; and in Madras 1 would commend this subject to
the consideration of those who may be entrusted with framing the rules
and regulations under which such works are undertaken.

All these evils would be avoided by a responsible department who
should not only construct, but give necessary attention to the working and
maintenance of the drainage, at the expense of the owners.

I am of opinion also that every facility should be given for the econo-
mical construction of the house drains. The mass of the people who have

264 DRAINAGE OF MADRAS.

to pay for them ate poor and can ill afford to do so, the order to expend
40 or 50 rupees is to them a Berious difficulty, usually they are desirous
of haying the benefit of the improvement, but oppose it rather than hire
to pay for it.

In such cases, the Public Health Act of England provides that, the
Sanitary authority may execute the work and hold the property as security
for payment of principal and interest in a certain number of years.

Thus for a loan of Rs. 100 with interest at 5 per cent, for 5 yean, the
quarterly payments would be Rs. 5-18 to pay off principal and interest in
that period.

I aro persuaded few people would object to the improvement carried oat
in this way ; I would therefore submit for the consideration of the Govern*
tnent, the desirability of such an addition to the Municipal Act as will
enable the Municipality to undertake the work of private drainage charg-
ing just as much as the work may cost, and obtain re- payment in the form
of private Improvement Rates collected in the ordinary way quarter!/,
with the other Taxes.

The actual cost of private drainage of premises is of course dependant
on their size, arrangement, and position ; it is also dependant somewhat
on the width of the road.

B8. A. P.

4-inch stoneware pipes cost, landed in Madras, per foot, 0 4 0
Laying in the ordinary way with concrete, • • . • 0 6 0

Total per foot, .. 0 10 0

For a email house the length required may be assumed

as 60 feet, at 10 annas, 31 4 0

Cost of connecting house drain with public sewer, . . 8 0 0

One syphon trap fixed, 3 8 0

Total Rs., .. 87 12 0

8hould a simple privy inlet be added without addi-
tional pipe, the cost will be 8 4 0

Total Rs., •. 46 0 0

This would be exclusive of the cost of cutting walls and repairing
brickwork disturbed.

The one item of connecting the house drains with the street sewer can
be in some degree reduced, by putting in the junction piece when the
pipe sewer is laid ; if this plan be adopted generally, it will not only re-
duce the cost by a length of pipe (which must be broken to get it out)

DRAINAOB OF MADRAS. 265

but it will obviate the risk of damage and disturbance to the pipe line
which to some extent is unavoidable ; moreover, there are some places
where the cost of the connection is donble what it would be in other places,
without any corresponding benefit to the house connected, as when the
connection is made with a 9 or 12-inch pipe, in place of 6-inch.

In consideration of all the circumstances, I recommend that the junc-
tion pipe for every house should be put in as the street sewer is laid, and
I have included in my Estimate an amount of Rs. 43,055 for this purpose.

For efficient record of the position of house drains, it is necessary that
a plan should be made of all premises drained, at a scale of 20 feet to the
inch ; at this scale the position of drain and water pipes, &c, can be ac-
curately shown ; each house-owner should be called on to furnish such a
plan of his premises on which to lay ont the drainage, or pay the cost of
it as a part of the house drainage to the Municipality.

The 100 feet revenue plan should then be corrected, and filled in with
the buildings, which are now entirely omitted ; if this be done, at any
time when examination of the house drain may be required, it will be
possible to ascertain its exact position.

The Act empowers the Municipality to supervise all additions and al-
terations to house drains.

The survey of the houses in every street should thus precede the execu-
tion of its drainage, as it is only by such means the exact position of the
connection can be correctly determined.

One other important matter must be borne in mind when arranging the
house drains.

As the system is not intended for surface water, the inlets to the house
drains must in every case be so arranged as to exclude rain and flood water.
Most of the houses, especially in the lower parts of the town, are raised
two or three feet above the road level. If the inlet be so raised to 80 feet
above datum, it will exclude flood water ; but it must also be raised a few
inches at least above the general level of the compound, backyard, or
other place where it may be fixed, to exclude rain wator ; and it must
always be subject to inspection by the proper officers.

It should also be a regulation that all inlets to house drains be trap-
ped by a syphon trap, guarded by an iron grating, and in the open air ;
should any pipe drain form an upper apartment or interior of the house
be brought to this trap, it should not be connected with the interior. Its

266 DRAINAGE OF MADRAS.

continuity should be broken, and the fluid be discharged a few inches
above the grating.

This does not apply where privy or water closet connections are required,
these apartments should be adjacent to an outside wall in all cases and
freely ventilated.

The soil pipe in the case of water closets should be carried to the
highest level the house admits of, and open at the top.

Where the premises are large, and several branch drains are construct-
ed, it is desirable to collect them into one pipe and construct a trap in its
length before it enters the sewer.

As I have before mentioned (page 244), the surface channels will be left
open as at present, this leads to a difficulty which it is most desirable
should be thoroughly understood.

Were these surface channels destroyed, filled up, or covered andcntoff
from the houses in any way, then the house owners would be compelled
to connect their houses with the new sewers, or the filth wonld be dis-
charged upon the road surface, an intolerable nuisance would be created
and speedily suppressed by the operation of the law.

Where however the surface drains are left as at present, and house
owners are content to allow matters to remain as they are, without con-
necting their houses with the new sewers, there would of course be no
departure from the usual state of things, and this has only to be of fre-
quent occurrence to render the entire work useless.

I would therefore strongly urge on the Government the importance of
doing whatever portion is taken in hand completely, rather than that an
expense should be incurred for the public sewers while the equally im-
portant house drains are left to the decision of the owners. The result
of this would undoubtedly be, in most cases, that when expense varying
aay from Rs. 10 to 100 has to be incurred, they will generally see reason
why matters should remain as they are and the expense be avoided.

I would venture to advise, that in the event of Government adopting
the scheme that it should be executed in separate and distinct portions;
and each should be well advanced towards completion before another is
undertaken. The first work I think should be confined to Black Town
and the Fort; the greatest existing nuisance would be removed, and I
believe, the most benefit derived from the expenditure of a given sum.
The construction of the Pumping Station, and the outfall sewer, should

DRAINAGE OF MADRAS.

267

be simultaneous with that of the Street sewers. I believe that this could
be completed within three years ; and the remaining portion could then
be taken up in divisions as considered most desirable.

The total estimate for Black Town and the Fort is, . . 7,07,109

The Pumping Station, 1,62,874

Outfall complete, 2,71,451

11,40,934
Add for Contingencies and Engineering, 15 per cent, 1,71,189

Total Rupees, .. 18,12,078
Statement of Quantities and Cost of the Drainage Works in the various

Divisions of Madras.

Description.

•a
I

a,
J 5

■ 4*

1°
It

It
•t

n
n

• ••

double,

n
n
ii

6-inch pipe,

9-
12-
15-
15-

Manholes,
Ventilators,
Lamp holes,

6*-pipe connecting honse drainage, Feet

Brick Sewer, 3' 6' x 2*V of 2 rings ','.
3,6,x2' 4' of 3
4» x 2' 8" of 8

X 8' 4* of 3 „ ,.

No.

Feet|249,578

28,375

2,440

1,000

»•
No.

n
ii
»

Bell-month,
Side entrance,
Manholes,
Ventilators,

ii
i*
ii

ii
ii

...

•••

ii
ii

823
426
285

11,209
1,401

18,215

8,260

•••

127,875

11,440

920

5,815

3,260

536

272

5,691

632

4,035

1,350

3,525

1,675

33,470
760

114

1,885

4,365

99,743
15,955

9J1V0

•*.

485

209

6,600

1,100

2,805

37,477
4,820
5,040

1
10
10

...

178

901

3,203

1,068

8
6
6

• a.

• ••

• •a

aaa

Quantity

548,148

56,850

8.400

15.985

8,260

2,086

1,055

449

28,688

4,251

25,020

1,360

11,785

1,675

The total cost of each division and work as given in the detailed Esti-
mate is as follows : —

Black Town and Fort, ..
Porsewalknm and Egmore,
Chintadripett, .. ••

Triplicane and Royapett,
Mylapore,

••

• ■

• •

BS.
7,07,109

4,12.568

1,06,007

2,68,278

94,197

Carried forward, .. 15,88,154

268 DRAINAGE OF MADRAS.

Brought forward, .. 15,88,154

Oat-fall complete, •• .. •• .. 2,71,451

Pumping station, . • . . • . • • 1,62,374

Syphons, •• • • •• •• •• 19,755

Total Rupees, . . 20,41,784
Engineering and Contingencies, at 15 per cent, 3,06,266

Grand Total Rupees, . . 23,48,000
The working expenses of the scheme I have proposed when fully car-
ried out will be as follows : —

Engine Ettabliihment.

1 Superintendent, at • • • . • . Rupees 300 per mensem.

1 Assistant, at „ 100 do.

3 Engine men, at 20 Rs., • • • • „ 60 do.

12 Firemen, at 12 „ •• .. „ 144 da

6 Coal men, at 6 „ • • • • „ 86 do.

6 Coolies, at 6 „ •• • • „ 36 do.

Total per mensem, „ 676
Fuel
Working one Engine, .. .. .- .. 8 hours per day.

„ 2nd „ 24 do.

Total 32 hours, Engine 85-horse power effective.

The consumption of Indian coal will be at the rate of 4£ fibs, of coal
per indicated horse power per hour.

The engine will give 65 per cent, of effective duty, and the total power

will be 54 horses.

H. F. lbs. hrs.

A, 64 x 4-5 X 32 _ ._ 01 . «

thus 557jr = 3-47, say 3J tons per day.

Rs. days. RS.

8*5 Tons x 21 x 30 = per mensem 2,205

Engine Establishment, 676

Oil, Stores and Contingencies, • •• 200

8,081
Working expense at Rs. 8,081 per mensem, annual coat, 86,972
The annual instalment necessary to repay Principal
28,48,000 in 80 years with Interest at 4| per cent
will be 1,44,148

or a total annual payment of Rs. • . 1,81,120

If the Principal be repaid in 50 years, the annual payment and work-
ing expenses will amount to Rs. 1,55,740.

DRAINAGE OF MADRAS* 269

Surface Draihagb. — The improvement of the Surface Drainage of
Madras is a rery large subject, one requiring much thought and many
levels to be taken, and probably great improvement might be made in
providing new, and improving the old, channels by which the water reaches
the Cooum or the sea as the case may be.

In only one case have I been able to extend my enquiries to this sub-
ject, and these refer to the Black Town sewer, of which the levels have
been taken.

The area drained by this sewer is about f ths of a square mile, one
quarter inch of rain per hour falling in this area would give about 8,000
cubic feet per minute.

The sewer is, I believe, well constructed of brickwork with a granite
floor, it was built between 1850 and 1856, at a cost of about 2± lakhs of
rupees. It extends from the sea near, and on the north of the Fort,
crosses the glacis to Umpherson and Davidson's Street which it traverses,
and a part of Popham's Broadway, till it reaches Old Jail Street, there
it turns to the East, and along this latter street to the sea.

At the South end it has a fall in 4,180 feet from 21*7 over datum to
18*7 at the sea ; 8 feet. The lower end is about the level of low water
in the sea.

The other portion is 6,900 feet long, and the fall is from 21*7 to 19*0
over datum, a fall of 2-7 to near low water.

If the sewer be perfectly clean and unobstructed, it would discharge
about 5,000 cubic feet per minute from each end, and would therefore be
capable of carrying off a little more than £ inch of rainfall per hour
from the area. But I am informed it requires to be cleaned out twice
per annum, it is probable, therefore, that very much less than its entire
capacity is available to take away storms when they occur.

Moreover, as the ends of the sewer are closed by pent stocks which
require to be lifted before the contents of the sewer can escape, it may be
that there is some obstruction on this account. Of course when the fall
exceeds £ inch per hour, flooding will occur.

For improving the action of the sewer, I would advise that gully pits
be constructed at every inlet, of sufficient capacity to receive and inter*
cept the road grit, which washes into it on the occurrence of every
storm : these should be cleaned out regularly.

If then the outlet to the sea be closed by proper self-acting sluices, I

VOL. V. — SKCOKD BBR11B. 2 O

270 DRAINAGE OF MADRAS.

think the sewer will be found to render greater service than at present in
discharging rain water.

I have found no road surface in this locality below the level of the set;
5 to 7 feet above mean sea level is usual, and 5 feet is about 3 feet 6
inches above high water.

China Bazaar Street is slightly higher, a few inches only, than Pop-
ham's Broadway, and causes a very slight obstruction to the flow of flood
water across the glacis of the Fort to the Cooum.

The existence of a mass of stagnant filth in this sewer cannot hot bo
prejudicial to the health of the locality.

Poblio Latrines. — In Calcutta and in Bombay also, a very large
number of the poorer population resort to Public Latrines, and pay a few
cowries for the accommodation. In Calcutta some of these places are
the property of individuals who derive very considerable emolument from
them. The Municipality also derive a Revenue from these Public La-
trines.

Where the Drainage Works are completed, these have now been altered
and the Water carnage arrangement adopted with the most perfect 6uccesi.

In Madras there are many of these places, they occupy large spaces,
and are a very decided nuisance where they exist ; for this reason thej
are generally removed from the immediate vicinity of crowded places,
and the people have some distance to travel to them.

If these Public Latrines were increased in nnmber, reduced in dimen-
sions and the water carriage system adopted, a great improvement would
be affected, and they could be placed wherever most convenient for those
who use them.

When the Drainage Works, are completed, one or two localities may
be selected in thickly populated places near to a Water Works Pipe,
wherein to try the experiment of an improved latrine similar to those in
use in Calcutta.

The arrangement consists of a water trough passing through or under a
small apartment into which the place is divided, the trough has a sloping
bottom, it is filled with water from a tap at the top when prepared for
use, and is emptied at the lower end, where an iron socket closed by a
wooden plug is arranged in connection with the sewers. After several
hours use, the plug is lifted and the contents of the trough discharged,
it is then re-filled with water and is again ready for use. At a cost of

DRAIN AOK OF MADRAS. 271

Bb. 2,400, a covered place to accommodate 20 persons may be constructed,
exclusive of the land.

Documents accompanying this Report. — A* Level Book, accompa-
nies tbis Report containing values of Bench-marks which have been
established in various points throughout the town, these Bench-marks are
blue whinstone posts numbered 1 to 122. The level of the squared tops
is the level taken, and they are all referred to a datum 20 feet below mean
sea level.

In taking these Bench-marks surface levels were taken also at 2C0
feet apart, in every street and road. These levels are written in blue
ink on the Plans, but are there made to indicate the height above mean
sea level.

The Revenue Survey* Plans at a scale of 100 feet to the inch, have been
found generally very correct, and are adopted as the basis of the scheme;
on these I have laid down the line and levels for every sewer; the gra-
dient and direction, as well as the height above datum at the different
junction of the sewers, are all shown on these plans.

♦Plans of the Streets and Working Sections of the same are also pre-
pared, on these the position and inclination of the 6ewers is shown.

These Plans and Sections are given for the whole area to be drained.
They have been carefully checked and may, I believe, be considered as
strictly accurate. Drawings of the Section of Sewers, Manholes, Syphons,
Pumping Station, and Sea end of outfall sewer, with an index map to
the various blocks of the Revenue Survey are also prepared.

The * Estimate book shows the name and number of the streets in the
various divisions, corresponding with those on the Revenue Survey. It
gives the length, average depth, and inclination of each street sewer ; the
street number into which it discharges ; the number of lamp holes and
manholes ; also the estimate for any special work, and for compensation
or damage to property; and the total cost of each division drainage.
A* list of the streets in the various divisions, numerically and alphabeti-
cally arranged, has also been prepared.

As an Engineer, it is no part of my duty to compare mortuary results,
but it is no small satisfaction to be able to point to cases where lives are
saved and sickness prevented.

The following is taken from the Administration Report of the Calcutta

• Not republUhed with thit Article.

272 DBAIHAGI OF MADRAS.

Municipality for 1878-74, as the total deaths occuring in that city during
previous years : —

1865,

•••

•■•

•••

• ••

23,242

1866,

«•

•••

• •«

20,283

1867,

•••

• ••

• •■

12,097

1868,

•••

••t

•••

•■•

• ••

13,738

1869,

•••

••■

•••

• a*

• ••

12,795

1870,

•••

•■•

•••

• ••

■ ••

•••

10,102

1871,

■••

•■•

•••

■ ••

■ ■•

• ••

10,300

1872,

•••

■••

•••

• ••

• ■•

••■

11,825

1878,

•••

• ••

•••

• ••

11,557

Calcutta, however, is far from being complete in its Sanitary arrange-
ments. The water supply is generally distributed, but at least one-half
of the community still have little or no benefit from the drainage works ;
all the more expensive portions are completed, but the less expensive
pipe system which will make these available to the great mass of the poor
native population still remains to be done, and during the present year I
believe the works are suspended ; Calcutta therefore even now is not in
the favorable position, it is to be hoped it will be when the works are com-
pleted. In 1869, the Water and Drainage works were first brought into
operation, and a marked change is at once visible.

But tables of mortality in this form entirely fail to convey the mil
value of a life saved ; it also means sickrust prevented.

Medical Btaticians know that for every life saved there is a large
number of cases, (28 may be taken as under the mark) of serious sick-
ness prevented, with all their concomitants of privation and misery; and
the heavier portion of this burden falls on the poor.

In a community like Madras, with its 8,97,552 inhabitants, if the mor-
tality can be reduced from SB to 23 per 1,000, as there is no doubt
whatever it may be, this would amount to no less a number than 8,970
lives, and in the proportion I have mentioned, no less than 1,14,160
cases of sickness per annum would be avoided.

It would be a great mistake to suppose that the community does not
pay for this, not only in the physical suffering, but in loss of money.

If we take 10 years as the period which is lost by a life cut off
prematurely, by preventable sickness, and its value at Bs. 2 per month
only;

And the cases of serious and unnecessary sickness as incapacitating

DRAINAGE OF MADRAS. 278

the sufferer for a period of two months from employment, we shall then
have as

RS.
Valne of life lost, 8,970 x 10 x 12 x 2, . • = 9,52,800
and by sickness, 1,11,160 X 2 x 2, . . «= 4,44,640

Loss per annum, Total R&, • • 18,97,440

It is not pretended that these figures are strictly accurate as applied
to Madras, they are believed to he rather under, than over, the actual
amount.

When, therefore, it is stated that it is too poor a place to indulge in the
luxuries of drainage, and water supply, let it be remembered that this is
one of the penalties of filth, and that it is chiefly paid by the poor who
cannot help themselves ; but the rich do not escape, and when surrounded
by such conditions as abound in this city, nature frequently exacts the
penalty from all, rich and poor alike, who neglect or break her laws.

274 DRAINAGE OF MADRAS.

APPENDIX.

The River Cooum.

12th February, 1875*

The condition of tbe river Goonm as the chief receptacle for the ear*
face water of Madras is of the greatest importance.

The area of the city is far too large to permit of any measures for
effecting its surface drainage, excepting by the ordinary means of gravi-
tation to a lower level ; and as the level of the sea is the lowest that can
possibly be obtained, it is evident, that if the river Cooum can be kept
down to this, it will be in the best condition for effecting the surface
drainage of the city.

It is, moreover, desirable for many reasons that fresh supplies of sea
water should enter with the daily tidal current — the presence of a stag-
nant lagoon of sea water closely adjacent to the most populous part of a
large city is most undesirable, — but when it is mado to receive the
sewage of the population for weeks and months together, as at present,
it becomes a source of nuisance and danger to health. The greatest bene-
fit to the Cooum undoubtedly will be the diverting of the sewage into
other channels, and to prevent entirely the contamination of its waters;
and should the very necessary works of drainage be executed, still in the
present condition of the bed of the River Cooum (which has for man?
years received the greater part of the sewage) the necessity for an improve-
ment in its condition will only be lessened in degree, and therefore, I
venture to offer for the consideration of Government, a few remarks on
the subject.

From a daily observation of the ' Bar ' since my arrival in December
last, and from information with which I have been favored by Colonel
Goddard, Colonel Moberly, and others, it is apparent that no regular
discharge of upland fresh water throughout the year can be expected; and
it is from the tidal influence alone that any power can be obtained towardi
the keeping of the ' Bar' open throughout the year; and the case at once
resolves itself into the question of quantity and velocity of the current}
entering and issuing four times in the 24 hours.

DBAIHAOB OF MADRAS. 275

In this view of the matter, the area of the Cooum affected by the tidal
influence, and regarded as a reservoir for the flood water at high tide, to
be discharged as the tide falls, is an important feature. The river when
in flood, as during October last, scoured out the entire channel through
the bridge, and a clean channel was left; this was the result of an
enormous body of water moving at a high velocity.

As the quantity diminishes at the cessation of the rains, the water of
the flood tide gradually finds its way in, and it becomes a contest
between the loose sand thrown up by ihe surf at the mouth of the river,
and the entering and issuing tidal water ; as this process goes on during
the North Eastern monsoon current, the river is forced towards the
southern end of the bridge, where there is a short groyne, and the drift
sand occupies £ths of the waterway of the bridge, leaving a narrow chan-
nel only; this channel is kept open for several months by the scouring
action of the tidal water in passing to and from the reservoir of the Cooum.
As the river succeeds in forcing for itself a channel through the
enormous quantity of loose shifting sand for several months, it may, I
think be expected that if some comparatively small means of assistance
were afforded, it would remain permanently open.

Those who have known the river before the rough groyne of granite
honlders above alluded to was placed on the sea side of the bridge at
its southern end, will be able to say how far or for what period the clos-
ing of the ( Bar ' has been protracted.

My observations during the past two months have shown that the
outlet of the channel into the sea shifts towards the north. A quantity
of sand accumulates on the ' Bar ' side at the head of the groyne, and
gradually increases in extent, causing the opposite or north side of the
channel to scour away the sand by the action of the waves which break
on its face during flood tide, and carrying the sand nearer to the bridge,
where a very considerable eddy is formed, and a quantity of sand is piled
up at the back of the shoal first formed as above ; as this action proceeds,
the northern side of the channe lbecomes more and more exposed to tho
action of the waves, and the silting up of the channel is more and more
rapid, nntil the time when the projecting shoal on the south side will
overlap the northern side of the channel completely (it now extends to a
point opposite the seventh arch from the southern end of the bridge) and
will soon completely overlap the channel ; in this condition of things tho

276 DRAINAGE OF MADRAS.

waves (which break nearly parallel to the shore) will commence to cat the
point of the shoal itself and drive it bodily in towards the bridge, and the
' Bar * will then at once be closed.

I am of opinion that if a channel of suitable width be formed by the
construction of groynes on both sides, and the entering and issuing water
be confined to this channel during the dry season, that a quantity of water
moving at sufficient velocity will be obtained to keep the channel open
throughout the year, by the scouring action of the tidal water alone.

I have roughly estimated the quantity of water which the river Cooum
will contain between the South Beach and Harris' Bridge.

The ordinary rise of the tide I learn is about three feet, for purposes
of calculation I have taken 2 feet 6 inches as spread over the area of the
Cooum between the above points, and I find the quantity to be about 16£
millions of cubic feet which must enter through the channel at the ' Bar '
in 6 hours ; this quantity in a channel having a sectional area of 300
square feet, would give an average velocity of 2£ feet per second. Of
course this velocity is not uniform, it is greatest about half tide of both
flood and ebb ; and at extreme high or low water the velocity for a brief
period is nil, but for a very considerable portion of the six hoars the
velocity will be much higher, from four to five feet per second, and I
consider quite sufficient to keep the channel with a capacity, such as
I have mentioned, open, if the loose sand at the mouth be so far confined
and controlled as to admit of the scouring action of the water being
concentrated on its sectional area only, and in a direction at right angles
to the general shore line.

I have repeatedly observed the water entering with a velocity at the
surface of four feet per second (and the channel I take to be about the size
I have indicated) under the present condition of things, but the mass of
sand it has to contend with, on both sides, along its whole length, is too
great to be overcome by the small stream opposed to it.

I am unable to say whether the waterway of the bridge is sufficiently
ample to admit of 50 feet out of its 500 feet, to be appropriated to the
construction of a groyne on the north side of the channel, but judging
from the other bridges higher up, where the waterway is very consider-
ably less, I should think 50 feet might be spared ; in that case I should
appropriate the third arch (from the south end of the bridge) to the con-
struction of the groyne which with the existing one on the south side

DRAINAGE OF MADRAS. 277

should be extended about 200 feet further seaward, and to a depth which
experience has proved to be the lowest point of scour under the bridge.

Should it be inadmissible to construct a groyne in that position, then
an independent opening further to the north would be necessary at a con-
siderable increase of expense.

The river in its shoal portion should be deepened so as to be from one
to two feet of depth at low water.

It would also be necessary on the approach of the monsoon season to
keep the sand at the Bar down to a level which would easily admit of the
flood water topping and scouring it away, so as to avoid any undue strain
on the permanent channel.

The upper reaches of the river may be immensely improved by train-
ing walls at intervals, to confine the stream during the dry season to a
defined channel ; the general bed being levelled, and it is I believe suffi-
ciently high for grass to grow upon ; not only would the general appear-
ance of the river then be improved, but its discharging power would I
consider be improved also.

Memorandum.

April 3rd, 1876.

Since the above was written the South-west winds and current have
fairly set in, and a body of sand from the South has accumulated at the
end of the groyne, about 100 feet in width measured seaward.

It has also advanced towards the North, and the Gooum up to a few
days ago has continued its struggle for existence. A week since the sea
end of the channel had moved northward about 400 feet from where I
first observed it; and in this process an enormous mass of sand had been
cut away from the land side of the channel. Suddenly, about 4 days ago
a tongue of sand about 250 feet in length shot forward from the growing
bank, and the channel was forced into a position about paralled with the
shore line ; the surf breaking over this sand has now closed the channel,
and the Cooum will remain a stagnant pool till the middle of October.

The view I took two months ago of this subject is confirmed by what
I have since observed.

W. C.

VOL. V. — SECOND 8KRIKS. 2 P

278 DREDGERS AND DREDGING.

No. CC.

DREDGERS AND DREDGING,

[Vide Plates XXXV. to XXXIX.]

By Mr. J. W. Barns, M. Inst. C.E. and F.R.G.8., Supdt., Canal
Irrigation, Bahawalpur State.

The utter inapplicability of any previously known type of dredger for
fulfilling the several conditions essential to successful canal clearance has
led up to this invention ; it is possible there are defects even in it, and
that improvements may yet be made which will still further simplify and
lessen the cost of the process.

Nevertheless, as far as at present worked out, the invention promises
to effect a great revolution in this class of work, for there is not a canal
or dock in the whole world where, as a labor saving machine, it cannot
with advantage be used.

Cheap as is labor in India, the author believes that dredging by the
system proposed can be accomplished, so as to compete successfully with
it, because, as the mode of working is so simplified, and as most of the
operations are, so to say, self-acting, what has to be done by manual
labor, can be done with a minimum number of hands.

For excavating soil from canals, the space within which a dredger hai
to work is limited ; the spoil to be removed is very often some feet in
height above the surface level of water in which the vessel intended to
dredge, floats ; so that she has to be designed, so as to be able to eat into,
and clear away, a sandbank ahead of her that may be as high as, or eren
many feet higher in level than, her own deck, and therefore high and dry,
and as the bed of many canals is often not more than three feet below

DRBDGBfiS AND DRBDGINQ. 279

the level of the lowest known fall of a river, her immersion (if she is
intended to work throughout the year) must be limited to a draft not
exceeding 2£ feet.

Lastly, after excavating the spoil, the work demanded from a canal
dredger is bnt half done, it being necessary, in order that the operation
may be complete, that the spoil be simultaneously deposited, not only as
far in from the edge of the canal bank as possible, bnt also that it be
delivered at a minimnn vertical height above the canal bed of 20 feet.

The invention embraces two distinct methods of accomplishing dredging
work, so as to fulfil all the above requirements in the most efficient and
economical way ; each of these is described hereafter.

Its great novelty consists in a hull of a peculiar shape, and also of a
mode of working, vide Plates XXXV., XXXVII. and XXXVIII.,
whereby the dredging is not only capable of being carried on without
intermission, bnt, paradoxical as it may seem, whether (according to the
sise of dredger employed) the breadth to be operated on be 25 or 100
feet, there is never any space to be bridged over between the side of ves-
sel, where the spoil leaves it, and the edge of the bank in from which the
spoil has eventually to be delivered, and thus, the whole length of the
overhanging and projecting shoot or pipe is utilized in conveying the
spoil excavated a distance in from the edge of the bank corresponding with
the length of the projecting shoot or delivery pipe.

The shape of the hull is such as to offer little resistance to the water
when moving from place to place, and it is intended that she should be
propelled by her own engine power, and be fitted with either twin screws
or hydraulic propulsion machinery.

It gives the largest bearing surface possible just at that point where the
strain caused by a projecting shoot or discharge pipe is greatest, and thus
affords the means of efficiently supporting a shoot or pipe of extreme
dimensions both as regards its length and sectional area ; 2ndly} as the
distance in from the canal bank on which the spoil has to be deposited, is
dependent on the height of the inner end of the shoot underneath the
tumblers, it enables the shoot (according to the size of the dredger) to
he placed at a height far exceeding that which has ever yet been at-
tempted, without incurring the danger of making the vessel top-heavy
or careen ; lastly, as the number of units of work to be got out of the
«Qgine employed is limited, both by the safe limit of height of discharging

280 DREDGERS AND DREDGING.

end of shoot, and also by that of its length, it follows that, if, by adopt-
ing a more suitable form of hull that admits of an improved mode of
working it, both height of delivery and distance of removal of spoil in
from the edge of the bank can be increased, so likewise can the nam-
ber of units of work, within a given space of time, be increased alto.

Both the dimensions of projecting shoots carried by dredgers of ordinary
type, and also the height to which such shoots can be supported, have,
hitherto, necessarily been considerably limited, even in dredgers of the
largest class, which seldom exceed 26 feet beam ; but by distributing the
superficial floating area of an ordinary 25 feet beam dredger over a hall
of the shape invented, its beam can be 50 feet at the point where so mncn
breadth is needed.

Both the shape of hull and the system of working it, is common to
both methods.

Dredgers of this type can be used as well for excavating an entirely
new canal of any breadth from 25 to 200 feet, as for clearing the spoil or
silt that may have accumulated in a canal that may have been already
made, the only postulate being that there shall be at least six inches greater
depth of water in the river or lake with which the canal or dock, which
is being excavated, is connected, than the draft of the vessel employed.

In Indian canal clearance, the great object is to have a dredger
capable of carrying as large an engine power as possible, with a minimum
draft of water and ability to support as long a shoot as possible ; the new
type of dredger, {Plate XXXV., Figs. 1 and 2,) with an extreme beam of
from two to four feet less than the least bottom breadth of the canal in
which it has to be worked, fulfils the above conditions to the highest degree
possible ; such a dredger would of course be able to clear the whole breadth
of canal offhand, at one operation, commencing at the head of the canal
and working in from the river as far as dredging may be necessary or
desirable ; there may be cases where, owing to strength of current or other
causes, it would be preferable to commence dredging, against the current,
or with the dredger's head up-stream instead of down-stream ; in such a
case the dredger would be dropped down the canal " stern foremost," to
the point where work is intended to be commenced, and, with her head
up-stream, would work her way back to the river, clearing the whole breadth
of the canal in her progress.

In the exceptional case of a dredger being needed to clear a canal of

PLA TE XXXV.

DREDGERS AND DREDGING.

Scale 48/r«c = 1 inch.

Btderopton canal bank

Bed mfttr cUafdmu

actional | 1

Section on A.B, after clearance

***\ Top utrface of tilt in canal b'l

Fig. 4.

fl« CD. before clearance

enrfate of eOl in carnal bed

Bad to whicm premioMtiw

to be dredged

SmHon pipe end

Foot of dope and bod
of canal after clearance

DBBDOBRB AND DREDGING. 281

200 ot eren 250 feet bottom breadth, there must be a limit of course
beyond which it would not be proper to increase the horse power, and
which would also place a limit on the floatage area necessary, and con-
sequently the extreme breadth of dredger, so desirable up to a certain
limit, would then be superfluous ; therefore whilst, as a general rule, there
ib a great advantage in having the hull at centre of as large a beam as
possible, there are limits beyond which its dimensions should be decided
with reference to the special locality in which the dredger is required.

In fact, although, for general purposes, the shape of hull as herein
designed, seems to meet all ordinary requirements, there is no real neces-
sity that it should be strictly followed, it is susceptible of numerous varia-
tions without necessarily departing from the principle on which the new
system of dredging herein described is based.

The exterior form of that part of the hull opposite the two sides which
support the shoot can be designed at pleasure of any dimensions or shape
that will enable the conditions dependent on required draft, least resistance
in moving through water, power of engines, and length and height of
shoot to be the best fulfilled ; where the bucket ladder or suction tube
is in the centre of the vessel, the two pivoting angles would of course
be made alike.

Description of the Bucket Dredger and of the mode of

working the Hull.

80 far as dredging and lifting the material by buckets is concerned, no
improvement on the old system has been made, but the system of ap-
pliance of the buckets by the methodical and simple mode of working that
part of the hull which carries them (whereby the exact place where each
bucket has to work, is so accurately and easily controlled by means of the
two friction capstans) is a great improvement on ordinary methods, be-
cause, with care, it is possible to ensure each bucket being properly
filled.

The newly invented dredgers are designed, as before remarked, with the
special object of eating into, and removing at a distance, the spoil of a
bank, no matter what may be its height above the surface level of the water
in which the dredger herself floats.

Let us consider the new proposed mode of working under those con-

282 DREDGERS AND DRBDOIMO

ditions, contrasting it, at the same time, with the method followed in
dredgers of the old type, so as to judge of its merits.

Dredgers of the old type, working under similar conditions, are depend-
ent, for their movement whilst working, on radius lines, the adjustment
of which, not being capable of being made self-acting, requires constant
attention, and a certain number of men in attendance on them, and with
all the care and precautions possible, it is a matter of such difficulty to
cause the buckets to work in the exact spot desired as to make it really
impracticable ; moreover, the difficulty attending any regular mode of
longitudinal dredging leaves no alternative but that of dredging crosswise.
In doing this, as the buckets do not, as a rule, present their mouths di-
rectly opposite to the material to be dredged, and as it has to find its way
into the buckets chiefly from the side towards which the line of cutting
is proceeding, the buckets often come up either empty, half, or three-
quarters full ; the result being that the outturn of work, under the old
system seldom exceeds half of that which, but for these disadvantages,
the engine could have accomplished.

A system of dredging which substitutes for the precarious and hap-
hazard style just described, one which provides for every successive bucket as
it passes around the lower tumbler, always being kept pressed up against
solid material directly in front of its month, must commend itself to all
who have canal dredging in hand, or who are interested in the matter.

It is only by longitudinal dredging, that is to say lengthwise, as opposed
to crosswise of the canal, that the cutting action of the buckets can be
the best provided for, and their filling themselves be properly secured,
and it is to a thorough developement of that system of dredging that this
part of the invention lays claim.

The hull, in plan, is shown in Figs. 1 and 2, Plate XXXV., and in plan
and vertical section also in Figs. 1 and 2, Plates XXXVII. and
XXXVIII.

When in the act of dredging, the hull swivels or pivots upon a centre
at one or other of the angles E or L (Figs. 1 and 2, Plate XXXV.)
according as she may be fitted with a bucket ladder or suction tobe
either at the side or centre.

At such pivoting or swiveling centre, an upright capstan actuated by
a donkey engine, is fixed, around which two or three turns of a rope
or chain AB or CD' stretched tightly along the bank of the canal near-

DREDGERS AND DREDGING. 283

est to the swiveling centre is taken, the ends of such ropes being securely
fastened on the bank, by anchors buried in the bank, or by strong stakes.

In Fig. 1, Plate XXXV., A BCD may be supposed to be a canal of
about the same bottom breadth as that of the dredger, or ABCD' a canal
of about double the dredger's greatest beam.

It will be evident, under the above arrangement, that when the cap-
stan before referred to, as constituting the pivot centre, is caused to
revolve, the dredger hull is moved backwards or forwards in the line
or direction of the works.

For cross warping, a Becond upright capstan is fixed any where be-
tween the pivoting angles E and L, having two or three turns of a rope
XPFFX' around it; the ends of snch ropes being secured to swivel'
blocks which traverse freely on the longitudinal side line as shown at X, X,
and passing through friction sheaves on the covering board at PP'
which sheaves are so placed that their centres are equidistant from the
centre of the capstan F* ; it will be evident that on motion being com-
municated to this capstan F, as the distance PX decreases, by so much
exactly will that of FX; increase, and vice versd ; and thus, by aid of
these two capstans, it will be evident that the projecting point of the
bucket ladder I, Fig. 1, or of that of the suction tube E, Fig. 2, can be
so directed as to work in any desired position or direction whatever,
within the limits of any canal, or place, of a bottom breadth slightly in
excess of that of the extreme breadth of the dredger hull.

Should there be any Engineer however sufficiently wedded to the old
system of radius warping barrels as to prefer it to the present jnethod,
in ordering a dredger of the new type, such warping barrels can be fitted
without prejudice to the other important points of the invention.

In Fi<i. 1, Plates XXXV. and XX XVIII. , the bucket ladder is placed
on one side of the vessel, and in Figs. I and 2, Plate XXXVII., the
bucket ladder is placed within a well, through the vessel's centre, vide
letters LL, Fig. 1, and MM, Fxg. 2, Plate XXXVII. This latter arrange-
ment offers no novelty, it having been in use years since on the river Clyde,
and may still be seen in the Suez Canal dredgers, and, where the height
of lift, and the distance in from the edge of the bank on to which it is
desired to deliver the spoil, are not special objects, there is an advantage
in the arrangement, but where the object is to secure the greatest height
of lift aa well as the most distant point of delivery of spoil in from the

284 DRHDGHRB AND DREDGING.

edge of the high bank that is possible, it will be obvious that this can
best be secured by placing the bucket ladder on the outside of that side of
the hull nearest to the bank on to which the spoil has to be lodged.

For instance, supposing the height of the upper tumbler in either
case to be fixed, then, as regards the shoot discharging from the cen-
tral bucket ladder, it loses a height of final delivery of the spoil equal
to what is necessary to secure the flow of the dredgings by gravitation
oyer a space equal to half the vessels extreme breadth, which, in one of
moderate dimensions would be 25 feet, and with the slope of shoot I
have proposed, viz., 1 in 4, the head so lost, allowing the centre of the
tumblers of the side bucket ladder to be 8 feet in from the outer edge of
the vessel's side, would be upwards of 4 feet.

This question, like many other similar details, can only be decided
after full consideration of every circumstance and condition connected with
the duty required, and more especially a knowledge of the locality where
a dredger is wanted to work, also of the height of delivery and lead of
the dredgings that may be desired or insisted on.

Both the bucket ladder and the suction tube, whether at the side as in
Figs. 1 and 2, Plate XXXV., or in the centre as at Figs. 1 and 2, Piatt
XXXVIL, are made so as to project a certain number of feet beyond the
vessels fore foot, as shown in Fig. 5, Plate XXXVI.

The necessity of this needs explanation.

If at the time the canal is being cleared, there is not sufficient water in
the canal to admit of the dredger floating over the place to be dredged, it
will be evident by inspection of Fig. 5, Plate XXXVI., (which though
drawn for illustration of the suction type, applies as far as this point ii
concerned to both systems,) that the distance which the dredger will be
able to dredge longitudinally or in the line of canal, will be limited to the
length that the bucket ladder projects beyond the fore foot of the vesieTi
hull, which, in present illustration, is supposed to be 10 feet, as is shown
also in Fig. 1, Plate XXXV., where the path of buckets along line IK ii
of that length, for referring to Fig. 5, Plate XXX VI., when point H will
have advanced to F and that of F to F', or, as in plan, Fig. 1, PlaU
XXXV., when the cutting buckets have advanced from I to K, the farther
progress of the dredger longitudinally would be arrested by the bank ahead.

By inspection of Fig. 4, Plate XXXV., it will be observed that in
following the path shown by letters FE, the cutting buckets actually

PLATE XXXVI.

DREDGERS AND DREDGING.

Fig. *.

BJigh

Err

J^^^^^^j^ Top surf ah of silt in

bed.

r y ~~jT

Fig. C. /,

i ^

Side step* of canal

Natural surface of ground

Bed of canal

Fig. 7.

S«d« elope of canal

Natural surface of ground
Side slope of canal

Canal bed

Scale 48 feet = 1 inch.

lowest fall of river 896' 32

\ Bed level ZW32
Bed of rieer

Proposed bed

Actual bed
Datum mw

Horisontal scale 2 miles = 1 inch.
Vertical scale 8 feet= 1 inch.

The actual gradient to tehiek the btd qf th* ahote f'anal was txcavatest teas t*) per mile,
the gradient above shown is that as since corrected.

DBEDGB&S AND DBKDOINO. 285

remoTe a prismoidal block shown by the letters a, b, c) d, e,f> g, h, sup-
posing the depth of silt as there represented, be four feet in depth, and
that it be of a material whose natural slope is 1 J to 1.

In Fig. 4, Plate XXXV., although theoretically FE' is the line of
greatest effect for the path of the buckets, practically, that shown by line
FK will be found nearly as effective, and although there is no more diffi-
culty in working through the path FK' than in that of FE, the latter is
recommended, because that path being parallel to the canal banks, only one
of the friction capstans (viz., that which moves the hull longitudinally)
need be set in motion during the whole time occupied in working from F
to E, and in running back to commence the cutting of a fresh longitudinal
prismoidal block adjoining that just previously excavated.

When the vessel has sufficient water to admit of her floating over
the material to be dredged, the distance to which the longitudinal pris-
moidal blocks can be excavated, before the dredger is ran back to commence
another line of prismoidal cutting can be varied at pleasure; it would
seem advisable, however, that such distance should be limited by the
length of the longitudinal side rope.

As long as the length of the projecting shoot remains unaltered, the
whole spoil excavated from the entire breadth being cleared by the dredger
will be deposited in a strip parallel to canal bank four feet wide at top, and
aide slope about 1 to 1. As the water rises in the canal, this parallel strip-
will be deposited one foot further in from the canal bank for every foot of rise.

Although, whether the bucket ladder is central or on one side, the
dredger is proposed to be so constructed a* that the portion of the hull
intervening between the point of discharge from the buckets or pump,
and the central pivot on which the vessel works shall, as far as possible,
be employed, or adapted, to support the tube or shoot ; in the one case,
viz., that where the bucket ladder is on one side of the vessel, its weight
ancL leverage, and also that of the bucket ladder, would have to be coun-
terpoised and counteracted by the weight and position of the engines
and boiler, and also with the addition of any ballast that may be neces-
sary. In the latter case, viz., that where the bucket ladder is in the
centre of the vessel, in my early dredger designs prepared some years
since, I fitted a shoot projecting on either side, one counterbalancing the
other, discharging the dredgings only in one at a time, viz., that on the
land side, or that on which the dredger for the time being pivots or is

VOL. V. — SECOND SERIES. 2 Q

286 , DREDGERS AND DREDGING.

working. In such case, the engiue and boiler would hare to be so placed
as to counterbalance the weight of the backet ladder only, so as to pre-
serve an even keel fore and aft.

As regards the method of suspending the shoots or tabes, no novelty
is claimed ; the large bearing surface of the hall affords ample means for
giving all the solidity required to the framework supporting the shaft-
ing, backets, backet ladder and tumblers.

On large works, or works where more than one side backet ladder
dredger is in use, it would be advisable to have some made right, and
some left handed.

In Fig. 6, Plate XXXVI., the dredger with side bucket ladder is shown
in cross section when water is at its lowest, and also the position of shoot
and upper tumbler at high water, here supposed to be 8 feet and 12 feet
in depth, respectively.

Up to point B, (the outer end of strut projecting from the vessel at
E,) I have supposed the shoot to be rigid.

Beyond point B the shoot is* suspended by the tie CD, secured to the
highest point of the framing which carries the upper tumbler.

There may be circumstances where it would be advisable to fold op or
entirely disconnect this projecting portion BDF.

In order to better distribute the spoil excavated, there appear to be
plausible reasons for not fitting this part of the shoot at all during tbe
season when river is not in flood, and adding on lengths as the river rises;
this plan would enable the spoil raised to be distributed with more uniform-
ity year by year; these, however, are details, which had best be discussed
with reference to the locality where a dredger is required to work.
' Having in view the large addition to the first cost of a dredger conse-
quent on the greatly increased strength of all the parts of the framing
and bucket appendages, the larger engine power absorbed, and the extn
draft of water involved, in providing for excessive distance of delivery
in from the bank, I think it would be well first to consider whether all
the economical and special purposes for which the services of a dredger
are called into requisition, may not be considered to have been duly fulfilled
by depositing the soil, which has been dredged, on to the nearest high point
of the inner edge of prior existing spoil, or on to the outer edge of the
cess or bern, and arranging for its removal therefrom by tip wagons,
gravitation, or manual labor, as may be considered best.

DREDGERS AMD DREDGING. 287

With regard to the extreme length of shoot, that shown in the Plate
is 60 feet : but this is not necessarily a limit, and with regard to slope of
shoot, I hare shown it as 1 in 4 : I am aware that as compared with the
slope of the Suez canal shoots that slope is excessive, but as the new type
of dredger admits of the inner end of shoot being raised to an excessive
height without the fear of the vessel being top-heavy therefrom, there is no
reason why we should not be liberal in this matter, the additional height
which enables a good slope to be given to the shoot enables its sectional
area, and consequently its weight to be proportionately diminished.

I have observed that in a shoot with a slope of 1 in 4, the material
dredged flows freely down the shoot without the aid of water.

On the Suez canal, the shoots have a very moderate slope of 1 in 20,*
and the material dredged (sand) passes freely down when mixed with a
quantity of water equal to half its bulk, whilst for clay, a slope of from 1
in 12 to 1 in 16 seems to have been sufficient, the clay needing only as
much water added as would moisten the mass.

There may be circumstances where a shoot of 60 feet length may not
under any circumstances even be considered necessary, and the height of
delivery required may be greater or less than here shown; of course in
proportion as length of shoot can be decreased, so can height of delivery
be increased, or vice verad. If required for canals such as we have in the
Bahawalpur State, and for general work, a medium sized dredger of the size
and design in Figs. 1 and 2, Plate XXXV., and Fig. 6, Plate XXXVL,
would suit; it would work in any canal of not less bottom breadth than 52
to 54 feet, and would thoroughly excavate or clear any bottom breadth from
54 to 104 feet. If wanted for a canal of less minimum bottom breadth,
the maximum breadth of hull would be lessened by as many feet as the
minimum breadth of canal in which dredger is intended to be worked is
leas than 54 feet ; the outer sides of the lozenge, though maintaining the
same parallel, would be proportionately lessened, and all other dimensions
might remain the same.

As it may often happen that the canal to be dredged exceeds in bot-
tom breadth the extreme breadth of dredger, it is desirable to explain the
method I propose for clearing such canal nevertheless.

Let us suppose the lines AB and CD', Fig. 1, Plate XXXV., to be
the exterior outline of a portion of a canal 104 feet bottom breadth, and

* FfcU ProfCMkmal Ptpert on Indian Engineering [Tint Berto,] No. CCXX.

288 DREDGERS AND DREDGING.

that the dredger available for its clearance has an extreme breadth of only
50 feet, and that Fig. 8, Plate XXXVL, shows the longitudinal section
of a portion of such canal requiring excavation or clearance.

Bearing in mind that no dredger of the improved type can clear any
ground or canal of a breadth which is not at least two feet or more, less
than that of her own extreme breadth of beam, it Is clear that the dredg-
ing of such a canal must be done in two operations.

I should commence by dredging the first half breadth of such canal,
as for instance ABCD, with the dredger's head down-stream, and, having
cleared as far in from the river as tlesired, should then run her back to
the river and reverse her, and if she was fitted with a side backet ladder, I
should drop her down, Btern foremost, to the point up to which she had
previously excavated, and having first laid down the longitudinal guiding
line on the bank D'C" should then commence dredging the remaining half
breadth of the canal CC'DD' by working with her head up-stream in
the direction of DD1.

If the dredger were fitted with a centre bucket ladder and second
pivoting centre at L, it would be optional whether the part DD'CC were
excavated by commencing at DD' or at CC

Supposing, however, a case where the dredger has a side bucket ladder,
and that there is not sufficient water in the canal to float the dredger, or
that there was a probability of a fall in the river before the part CC
DD/ was cleared, I should select a point in the canal, in from the river
where, by erecting a temporary dam across the bed of the canal, I should
be sure of having at least six inches more water standing against it than
the greatest draft of the dredger, even when the parent stream may bare
fallen to its lowest zero, and thus after having cleared the first half breadth
with her head down-stream, I should ensure her having sufficient water to
float her for commencing the second half breadth with her head up-stream.

In this instance, the proper place for such a dam would be at the end
of the fourth mile, vide Fig. 8, Plate XXXVL, where, by its erection
there, the necessary conditions would be fulfilled.

For clearance beyond that, a similar operation would have to be repeated.

Instead of running the dredger, back to the river to be reversed, bays
may be constructed at points along the canal, of size sufficient to admit
of the dredger being turned round end for end.

In the case of a dredger built for permanent duty in a canal which may be

DREDGERS AVD DREDGING. 289

fitted with head sluices, (which would prevent her having access to the river
for the purpose of turning,) such bays would of course be indispensable.

In the aforegoing remarks regarding the maximum breadth of dredger
hull admissible in any canal of a given bottom breadth, I have supposed
the canal to be straight. In a canal with very sharp curves, the maxi-
mum beam possible in a straight canal would have to be curtailed propor-
tionately with the decrease in radius of curvature'; for excavating portions
of the breadth in a curve, and often in excavating the first portion of the
canal head in from the river, there would be an advantage in having the
means of working on a pivot at the end of the vessel, say M, Fig. 1,
Plate XXXV. ; in such case, capstan E may be movable, and cross mo-
tion would have to be effected by radius lines worked from winches.

In Figs. 6 and 7, Plate XXXVI., a conical friction roller will be ob-
served fitted on to the lower end of the spindle of the capstan near point
E ; this will prevent point E from grazing the bank when the vessel is
moved longitudinally. In order to give egress and ingress between the
vessel and canal bank at all times, a projecting platform on a level with
the vessels deek will be fitted near the angle E.

When our Indian rivers are at their lowest fall, it is essential in order
that dredgers may be able to work in canals at that season, that their draft
of water should be as little as possible, and that is why I fixed on 2£
feet as a maximum limit.

It is questionable whether, in the case of dredgers of the bucket type,
these can ever be turned out with a less draft than 2$ feet when working,
but,' as regards those of the suction type, I see no reason why they should
not be constructed with a working draft of 1 foot 9 inches or even less ;
the draft must however necessarily .be much dependant on the height,
length, and arrangement, of the shoots or discharge pipe.

There are of course numerous situations where it may be advisable to
employ dredgers of this type, and where draft of water need not be con-
sidered ; in such case, the size, and consequent cost, of hull may be consi-
derably lessened, and if necessary the strength of hull be increased.

Hence, itis evident, thatin ordering dredgers of this type, builders should
be famished with full particulars of every circumstance connected with the
locality where they are intended to be used.

The invention is patented in England, under Specification No. 8789,
dated 3rd November! 1874! and dredgers on the new principle can be man-

290 DREDGERS AMD DBEDGINO.

ufactured there, without restriction, by any one, on payment of a nomi-
nal royalty. The invention not haying been protected in India, is the
property of the public here. s

Description of the Suction Silt Ejector.

The second type of dredger called the " Suction Silt Ejector," bat
been designed specially for the clearance and ejection of quicksand, silt
or indeed any kind of material coming under the denomination of sand in
a state of comminution, and liquid mud, such as is fonnd in all Indian
canals and also in most tideways, harbors and docks. In India its dm
would more generally be con6ned to the clearance of a substance de-
nominated " silt, " a substance which is always in suspension in flowing
water and which seems to be the universal medium in which the normal
spring water level is found throughout the alluvial plains of the Punjab
and Gangetic valleys.

It is to that substance we owe the shifting natnre of so many of our
Indian rivers and also the sandbanks and bars which so seriously impede
their navigation, and which often block up our best harbors, and lastly,
it is the great bane of nearly all canals drawn from any river in the
plains, inasmuch as the water and silt are so intimately combined sad
intermingled, that for every thousand measures of water, at least one mea-
sure of silt must be accepted ; one-half of which invariably separates from
the water and settles in some part or other of the canal, and has to
be regularly or periodically removed from the bed ; otherwise, so insidi-
ous is its natnre, that, left undisturbed, any ordinary artificial watercourse
cut through alluvial soil, no matter with what degree of perfection and
skill it may have been constructed, would, in the course of a few years,
become completely silted up.

The almost insurmountable difficulty of excavating canals in the plains
to a depth below spring water level sufficient to ensure their perennial
flow, (owing to the water lying in a stratum of either quicksand or of fine
micaceous silt, which being of such small specific gravity has hitherto
baffled all attempts at clearing to the depth required by any known
process,) is at the present moment the one great obstacle in the way of
opening out a cheap class of perennial canals from our Indian riven,
owing to the heavy outlay necessary for constructing a weir across the
river of supply, in order to obtain the head or depth of water wanted.

DREDGERS AMD DREDGING. 291

For achieving this great object, to clear sandbanks obstructing naviga-
tion, whether in rivers or tidal channels or harbors, and for maintaining
perennial flow in running canals by removing silt as it deposits, the " Suc-
tion Silt Ejector " is especially adapted. Like the bucket type before refer-
red to, it is possible to clear (according to the size of dredger employed)
a canal of 200 feet bottom breadth with the same facility as one of 25 feet,
(no matter to what height above the level of bed silt may have been depo-
sited,) and can convey the spoil so cleared a much further distance in from
the canal bank than is possible with the bucket type.

There are certain axioms connected with this process, however, which
most be thoroughly understood before the process itself will be intelligible.
The silt of the Indian rivers has a speci6c gravity when dry, of 1*45 ;
when fully saturated with water, of 1*74; subjected to any velocity up to,
and exceeding four to five feet per second, it becomes suspended in water,
and in such state of quasi -fluidity, it is amenable to the same laws as any
other fluid of similar density.

When fully saturated silt is mixed with an equal volume of water, its
specific gravity is reduced to 1*88, and with half its own bulk of water,
the specific gravity is 1*49.

As the velocity through the tubes of a centrifugal pump, in all but the
smaller sizes, (which from their small discharging power are inapplicable
to a process on such a scale as herein contemplated,) is nine feet per second
and upwards, and as remarked above, as the silt of most of our Indian
rivers becomes suspended in water when subject to a velocity of five feet
per second and upwards, it is evident that if the end of the suction tube of
a centrifugal pump be immersed in amass of liquified silt, it can be pump-
ed or forced to a distance under the same conditions as any other liquid
of similar specific gravity ; further that, as compared with water, the only
difference between pumping it and pumping liquified silt would be that
the latter would need more power directly proportionate to the relative
specific gravities of the two substances, which in this case would be as 1-38
to 1, supposing the water incorporated with the silt to be of equal volume
with it, but the ordinary form of the pump itself would need a slight
modification.

The remarks on, and explanations of, the bucket dredger, and the mode
end system of working the same, apply generally to the suction silt ejection
dredger, and therefore need no recapitulation.

292 DRKDGER8 AND DRBDGIKO.

In the process of excavating, raising and delivery of the silt, there is
however a great divergence from that of bucket dredging ; indeed except-
ing in shape of hall, and the system of working it, there is nothing ia
common.

Instead of a cumbersome and heavy projecting shoot, whose extreme
point of delivery in from the edge of canal bank, we may assume as 80 feet,
requiring not only its inner end to be set at a great height to admit of
the spoil lifted by the buckets descending to its place of deposit by force of
gravity, but demanding also a very strong framework to carry it and 4be
shafting, and to support the weight of the bucket ladder and upper tum-
bler on which the buckets revolve, we have in place thereof simply •
centrifugal or other pump with its suction and discharge pipe, the latter
(supported by a mast or pair of shears) projecting but a comparatirely
short distance beyond the vessel's side, with the capability, when its outer
end is at a vertical height of only 26 feet above the canal bed, of deposit-
ing the material raised a distance of 328 feet in from the edge of the
bank, and the option of still further increasing that distance by merely
raising the outer end of the discharge pipe, vide Fig. 2, Plate XXXV.,
and Figs, 5 and 7, Plate XXXVI.

The simple and ingenious method of suspending the projecting discharge
pipe, and that of fitting it with a universal joint at E, is the invention of my
Co-patentees, Messrs. Simons and Brown.

The economy of power involved by Messrs. Simons and Co.'s universal
joint will be evident, seeing that were the projecting discharge pipe rigid,
if of the height shown in Fig. 7, Plate XXXVL, its extremity being a
horizontal distance of 48 feet beyond the vessel's side, at the time of high
water — its end A would be in the position A*, which would necessitate a
lift through one-third more vertical height than is wanted, whereas, by
means of the universal joint, end A can always be kept at the same vertical
height above the bed by lowering it gradually as the water rose, or lifting
it when the river fell.

There is another advantage besides in this arrangement, and that is that

when moving from one part of the river to another, the projecting end can

be triced up clear of the river bank or of boats or vessels passed on the way.

In the section, Fig. 7, Plate XXXVL, E'A' shows the inclination and

position of the projecting pipe when there is 12 feet of water in the canal.

In this section, the discharge pipe is shown projecting 48 feet horison-

DREDGERS AND DREDGING. 293

tally beyond the side of the vessel with its discharging end A 26 feet
above the level of canal bed. This shows a type, bat in no wise implies a
limit in either case, it merely foreshadows the large margin to which it is
possible to increase, either of the above dimensions in situations where it
may be deemed desirable to do so.

Silt is such an insinuating material, (and under pressure it would be
more so,) that I fear whether in practise it would be possible to manipu-
late a discharge pipe with such a joint, however promising it may appear
in theory ; if however, it is attempted, surprise must not be felt if disap-
pointment ensues.

I see no reason, however, why an ordinary coupling joint admitting
movement of projecting arm through a vertical plane should not answer.

Experience on the Suez canal has shown that the sands there met with
when intermixed with half their volume of water, are capable of descend-
ing by gravitation, a slope equal to 1 in 25, and, as the discharge end of
projecting tube in design is 12 feet above level of ground surface, it will
be evident from the above hypothesis, that when once rasied to the point
A, the material would flow off to a point 300 feet distance.

I have carefully examined the sand of the Egyptian Desert, and found
it (technically speaking) sharper than the silt of our Indian rivers, and
deficient in mica to which Indian silt owes its low specific gravity, conse-
quently, as compared one with the other, (fall and volume being the same,)
the semi-fluid silt of lesser specific gravity would flow faster than that
of greater density, and, therefore, in order to attain an equal speed of flow
with both materials, the lighter of the two would need less slope, and would
consequently transport itself to so much further distance.

The silt suction process admits of both longitudinal and cross dredging
as I will explain.

For cross dredging, the end of suction tube terminates in a double head
vide plan, Fig. 2, Plate XXXV., and elevation at Fig. 5, Plate XXXVI.,
and the same on enlarged scale in Figs. 5 and 6, Plate XXXVII.

The suction ends of this double head would of course be used alterna-
tely; that is to say, when the vessel is working, for instance from C to-
wards 8, Fig. 2, Plate XXXV., the pump would be supplied from the left
side suction end, and vice vered ; a throttle valve is fitted within each suction
end, in such a manner that by a simple movement whilst one of the valves
is being closed the other would be opening, and vice vered.

VOL. V.— 8ECOND SERIES. 2 R

294 DREDGERS AND DREDGING.

This process of dredging is very simple, and will be understood at once
by inspection of the Plates.

As soon as the dredger has cleared throngh the circular arc from G to
B, Fig. 2, Plate XXXV., and the next arc beyond has to be commenced,
the end of suction pipe will be raised, the vessel propelled forward as ne-
cessary, and the suction pipe end be again lowered.

iheh own weight will sink the ends into the silt ; during the interval
occupied by the ends working down through the silt, to the bed level,
both throttle valves should be kept half open, and when the cross dredging
commences, if working from left to right, the left valve would be closed,
and the right valve be kept open, and vice verad.

The principle on which the feed of the suction pipe end depends is that
of undermining, as for example is sketched in Fig. 5, Piatt XXXVIL,
in which, at point F, a revolving agitator or rake is placed, which stirs
up and commingles the sand and water preparatory to its being sucked
in at the end of the suction tube.

This agitator is kept in motion by gearing connected with the axis
of the centrifugal fan.

A most valuable suggestion has been made by Mr. Molesworth, M.
Inst. C.E., on the subject, of which the writer has a high opinion. That
gentleman proposes to undermine the silt by jets of water acting on it
underpressure, and so dispense with the mechanical agitator entirely, and
consequently the wear and tear inseparable from gearing placed in soch
a position ; attention having been drawn to both methods, it will be opea
to experiment to determime which is the most suitable.

Now with regard to the form to be given to the end of the suction tube.

Silt in a state of repose assumes a slope of 1^ to 1. In undermining
the silt, this is the angle which it will continually be trying to arrive at.
The disturbance occasioned by the undermining would practically never
allow the silt which is being acted on, and which is immediately in front
of the end of suction tube that may at the time being, be working, to
assume that angle ; the end of the tube, however, has been designed of a
rectangular shape, and so as to present itself to the silt at the lowest
possible angle as shown in vertical section, Fig. 5, Plate XXXVIL

The main is here supposed to be 18 inches diameter, and the suction
end 18 inches square, the vertical height of upper lip of 6Udion above
the horizontal plane of lower lip F being about 10 inches.

DREDGERS AND DBBDGING. 295

With regard to the line of silt immediately in advance of that portion
of any arc that may have been either wholly or partially cleared, viz., that
for instance marked x X X in Fig. 2, Plate XXXV., it is supposed
that in working from C towards B, the line marked X X is really the
foot of slope of the silt of which DDD is the surface.

Fig. 8, Plate XXXV., shows the plan of a canal supposed to be silted
four feet deep, and on it is shown the path of the suction pipe in the act
of dealing any circular arc through soil, whose natural slope is 1 J to 1.

DC shows the cross section immediately in front of the suction tube
end, and AB the cross section in rear of the suction tube. The end of
the suction tube being supposed to be 1 J feet square, the portion colored
lake is the area excavated per each running foot of passage of suction
tube through the circular arc.

Whatever may be the shape of end of suction tube adopted, there is one
great point to be aimed at, viz., to keep it as much as possible well entered
into the silt which is being attacked ; the plan here shown seems tbeoret*
ically good, doubtless experience will suggest inprovements, and it would
seem advisable that spare ends of different shapes should be sent with any
dredgers of this type first ordered, so that trial may be made as to which
is the most effective.

Instead of a double headed suction end, a single curved suction end may
if preferred be used, with this difference that the dredging could not so well
be done crosswise as longitudinally, and on this point the same remarks
as on bucket dredging apply equally to this.

In Fig. 5, Plate XXXVI., the extreme end of suction tube projects 10
feet beyond fore-foot of the vessel ; the only inconvenience apparent from
this arrangement is the weight of the tube when charged with silt and
water. I propose to counterbalance this by running back a trussed lever
from G towards E, which would enable the suction tube GF to be raised
or lowered with a minimum expenditure of power, and at the same time
instantaneously.

Every new Invention that comes before the world is liable to criticism,
and this I rather court than otherwise, and I trust that such of my friends
as are interested in dredging, and who may take the trouble to wade
through this somewhat lengthy description, will criticise the same in a
friendly spirit, and that they will favor me with any suggestions that may
now occur to them, or that may hereafter occur where any of them have

296 DRBDGKRS AND DREDGING.

an opportunity of seeing any of these dredgers at work, and should there
be any point requiring elucidation which is either not touched on in this
description, or wKch is not sufficiently clear and intelligible, it will be a
pleasure to the author to discuss the subject with any Engineer or other
person interested in dredging.

Provisional Specification, dated 3rd November, 1874.

This invention relates to, and consists in a new or improved form and
arrangement of the hull and machinery, and of the discharging shoot or
pipe of dredgers for excavating and deepening channels, canals, rivers,
basins, docks, or other similar works, and for depositing the dredged
materials on the adjacent banks or wharfs, or into barges or other recep-
tacles, and also to a new or improved system or mode of working the
dredgers whilst performing these operations.

The hull of the dredger is in plan of a double triangular form, that is to
say, it is formed of two triangular shaped figures having their bases
united.

When in operation, the hull of the dredger is attached at one side or
end of the line whereat the bases of the triangles meet to a point, on
which it is capable of moving as on a pivot or centre, so that the outer
ends or points of the triangular figures and the bucket ladder or suction
pipe are moved in a curved arc across the face of the work which is being
excavated or dredged. The dredger is drawn across the face of the work
by ropes or chains stretched across the work approximately in the line
which forms the chord of the arc described by the end of the bucket lad-
der or suction pipe. The rope or chain, or ropes or chains, have their
extremities fixed or anchored on the banks, and it or they is or are turned
one or more times round a capstan or other similar purchase, preferably
placed at or near the fore part of the vessel, so that when motion is com-
municated to the capstan, the fore part of the dredger is hauled to any
side of the work by winding on the chain or rope. The position, however,
of the said capstan is not confined to the fore part of the vessel, as it may
be placed at any other suitable point thereon, and instead of one capstan
two or more such capstans may be used, and operated either from the en-
gine direct, or from a small donkey engine provided for that purpose.

The dredger is moved in the direction of the length of the channel,
canal, or other work by another rope or chain fixed at its two extremities

DRBDGBR8 AND DREDGING. 297

on the land or near the bank in a direction parallel to the length of the
channel or canal being excavated, that portion of the chain or rope inter-
mediate between the fixed extremities being passed dne or more times
round a capstan or other suitable purchase situate on the point or pivot
whereon the dredger is centered.

The bucket ladder may either pass through a central well in the hull,
or it may be situated at one side, or bucket ladders may be placed at two
or more sides, and the shoot or tabe into which the dredgings are deliver*
ed by the buckets is made to project in the direction of the land or bank,
or towards any suitable receptacle into which it is desired to deposit the
dredgings, the dredger being so constructed, that the portion of the hull
intervening between the point of discharge from the buckets and the point
whereon the dredger is centered is employed to support the tube or shoot.

In some cases the dredger is provided with a receptacle, into which the
dredgings fall from the shoot. In this receptacle an agitator may be
placed which mixes the dredgings with water, in which state or condition
they are forced through a line of pipes, and deposited on to, or in from the
banks, adjoining, or at the sides of the work, or into receptacles by the ac-
tion of centrifugal or other pumps.

In combination with the dredger herein-before described, any arrange-
ment of apparatus other than the usual bucket ladder which is suitable to
the nature of the soil to be dredged may be employed. Instead of form-
ing the hull of the dredger of two triangles, as herein-before described, it
may consist of one such triangle in form, or it may be made angular on
two sides and curved on the third side without interfering with the effi-
cient working thereof.

In lieu of anchoring each end of the hauling or warping chain or rope,
or chains or ropes, by which the dredger is moved through an arc from
one aide of the work to the other, as herein-before described, bights or
loops may be formed on the extremities of the said chain or rope, or
chains or ropes, through which guide ropes or chains stretched tightly
along the banks of the work pass, and by this means the necessity of
shifting the anchorage of the aforesaid hauling chain or rope, or chains or
ropes, when the dredger is moved forward is obviated.

The steam after it has passed from the engines which drive the ejecting
pumps, when such are used, may be conducted through, and caused to
actuate the engines which drive the dredging buckets.

298 DREDGERS AND DREDGING.

Specification, dated 1st May, 1875.

The invention relates to and consists in a new or improved form and
arrangement of the hull and machinery, and of the discharging shoot or
pipe of dredgers for excavating and deepening channels, canals, rivers,
basins, docks, or other similar works, and for depositing the dredged mate-
rials on the adjacent banks or wharves, or into barges or other receptacles,
and also to a new or improved system or mode of working the dredger
whilst performing these operations.

The hall of oar improved dredger is in plan of a double triangular form,
that is to say, it is composed of two triangular shaped figures having
their bases united.

When in operation, the hull of the dredger is attached at one side or end
of the line whereat the bases of the triangles, meet to a point on which it
is capable of moving as on a pivot or centre, so that the outer ends or
apices of the triangular figures and the bucket ladder or suction pipe,
according to the character of the dredging mechanism is moved in a curved
arc across the face of the work which is being excavated or dredged. The
dredger is drawn across the face, of the work which is being excavated or
dredged by one or more ropes or chains stretched across the channel,
canal, or river, in a line forming a chord of the arc described by the outer
end of the bucket ladder or suction pipe. The said rope or chain or ropes
or chains, is or are at one end fixed or anchored to the banks, and it (or
they) is (or are) turned one or more times round a capstan or other simi-
lar purchase preferably placed at or near the fore part of the vessel, so
that when motion is communicated to the capstan, the fore part of the
dredger is hauled to either side of the work by winding on the chain or
rope. The position, however, of the said capstan is not confined to the
fore part of the vessel, as it may be placed at any other suitable point
thereon, and instead of one capstan, two or more such capstans may be
used and operated either from the engine direct, or from a donkey engine
provided for that purpose.

In lieu of anchoring each end of the hauling chain or rope or chains or
ropes by which the dredger is moved from side to side of the channel as
herein-before described, bights or loops may be formed on the extremities
of the said chain or rope or chains or ropes, and these are thereby coupled
to the guide ropes or chains stretched tightly along the banks of the work,
and by this means the necessity of shifting the anchorage of the aforesaid

PLATE XXXVII.

PLATE XXXVI! L

PLATE XXX VI II.

i±

— U ll

l-l-.l

I -i I I I_l. 1_^_T

i I I Z I_T

DHBD0BR8 AND DREDGING. 299

hauling or warping chain or rope or chains or ropes when the dredger is
moved forward is obviated.

The dredger is moved in the direction of the length of the channel,
canal, or other work by another rope or chain fixed at its two extremities
on the land or near the bank, in a direction parallel to the length of the
channel or canal being excavated, or the guide rope or chain herein-before
referred to may be used for that purpose, that portion of the chain or
rope intermediate between the fixed extremities being passed one or more
times round a capstan or other suitable purchase, situated on the point or
pivot whereon the dredger is centered.

The bucket ladder may either pass through a central well in the hull, or it
may be situated at one side, or bucket ladders may be placed at both sides,
and the shoot or tube into which the dredged spoil is delivered by the
buckets is made to project in the direction of the land or bank, that is to say,
at right angles or otherwise to the length of the dredger, or towards any
suitable receptacle or place into which it is desired to deposit the dredg-
ings.

In some cases the dredger is provided with a receptacle into which the
dredgings are discharged, and thereafter mixed with water by an agitator,
and forced by centrifugal or other pumps through a line of pipes, and so
deposited on to the banks adjoining or at the sides of the work, or into
any suitable receptacle.

In combination with the dredger herein-before described, any arrange-
ment of apparatus other than the usual bucket ladder may be employed,
according to the nature of the soil to be dredged, and instead of forming
the hull of the dredger of two triangles as herein-before described, it may
consist of one such triangle in form, or it may be made angular on two
sides and curved on the third side without interfering with the efficient
working thereof.

Another part of our said Invention consists in utilizing the steam which
passes through the engines which operate the ejecting pumps (when such
are used) by conducting the Bteam when exhausting from the ejecting
engines through, and causing it to actuate the engines which drive the
dredging buckets.

And in order that our said Invention may he properly understood, we
now proceed more particularly to set forth the system, mode, or manner,
in or under which the same is or may be used or practically carried into

800 DRBDGSR8 AND DREDGING.

effect, reference being had to the annexed Plates, and to the letters tad
figures marked thereon, that is to say : —

Fig. 1, Plate XXXVII., is a vertical section of onr improved form of
dredger Fig. 2, being a plan of the same. As shown by these Plates, the ~~^
dredger consists in plan of a " diamond " shaped figure, rhombus, or two
triangles united at their bases, the minor diagonal a, b> constituting a base
line upon which are erected the two triangular figures forming the fore and
aft portions of the hull. Upon the diagonal a, ft, and at the port or staiboaid
side of the dredger hull, a centre or pivot A is situated, which may consist of
an eye or block through which the hauling rope or chain B passes, but which
is preferably an upright or horizontal capstan or winch around which the
rope or chain B is coiled once or any greater number of times. The ends
of the rope or chain B are fixed to the bank of the river, channel, or caul
being dredged, so that when the capstan or winch constituting the pivot j
A is caused to revolve, the dredger hull is moved backwards or forwards
in the line or direction of the works. When a mere eye or block is em-
ployed to connect the dredger hull to the rope or chain B at the point A,
auxiliary ropes or chains 'must be used, extending parallel to the guide 1
rope or chain B, and having their extremities either attached thereto or I
fixed to the bank by means of separate anchors, kedges, or fastenings. I

The auxiliary rope or chain or ropes or chains may be passed into the
hull through a swivel friction sheave, and after being coiled a sufficient
number of times around a capstan or winch barrel, is (or are) passed out
of the hull through another friction sheave, but in lieu of either of these
methods for moving the dredger hull in the direction of its length, the
ordinary fore and aft hauling chains or ropes C and D may be employed,
and coiled upon capstans or winches E situated at each end of the hoD, i

as shown on the Plates. A similar arrangement of apparatus is employ-
ed to move the extremities of the dredger, and consequently the bucket,
ladder, or suction pipe across the face of the work. This is effected by
the employment of ropes or chains F, the ends of which are anchored or
otherwise fixed to the banks on each side of the dredger hull. Die ropes
or chains P are then passed round purchases G, and coiled upon the rope or
chain barrels H of the winches E situated at each end of the dredger
hull. By operating the side winches so as to coil on the rope or chain
extending from one side of the dredger and slack out that extending from
the other side, the hull is caused to turn upon the fixed pivot at A, and

PLATE XXXIX.

DREDGERS AND DREDGING. 301

the ends thereof are so made to describe an arc as indicated by the dotted
lines on Fig. 2, Plate XXXVIL, whereby the dredging backets or suction
apparatus is caused to act upon the whole breadth of the work, as shown
more clearly at Fig 3, Plate XXXVIL, which is a diagram plan of a
dredger hall I fitted with a suction pipe J, and floating between the banks
K of a river or canal ; Fig. 4, Plate XXXVIL being an elevation corres-
ponding to Fig. 3, Plate XXXVIL The hall I is centered or pivoted at
the point A, and by hauling on the ropes or chains last described, the
ends of the dredger are warped across the stream or channel, and the suc-
tion pipe end caused to describe the aro shown at Fig. 8.

Instead of employing two ropes or chains F for each side of the
dredger, one such rope or chain may be used at each end of the hull, and
passed around a single upright or horizontal capstan or winch situated
thereon, and instead of anchoring or otherwise fixing the extremities of such
ropes or chains to the banks of the works, they may be secured to guide
ropes or chains extending along the banks, preferably by means of an eye,
bight, or sheave, and by this means the necessity of shifting the anchorage
of the cross warping ropes or chains at each forward or backward move-
ment of the dredger is obviated, as the loop or bight slides along the
guide ropes or chains as the position of the dredger is advanced.

As it is necessary that the herein-before described cross hauling ropes
or chains should be in a constant state of tension, so as to keep the
dredger in its position relatively with the banks of the river, channel, or
canal being excavated, the said ropes or chains are preferably attached to
their anchorages on the banks or to the guide ropes or chains last referred
to by means of blocks and tackle, so that as the dredger hull rises or
falls with the water level in obedience to tidal or other influences, the cross
hauling ropes or chains may be lengthened or shortened to suit the height
of the water line.

The backet ladder L, Fig. 1, Plate XXXVIL, or the suction pipe
employed in lieu thereof, may be suspended in a well M, Fig. 2, formed in
the ordinary manner at the central part of the dredger and extending to-
wards one end of the hull or otherwise. The bucket ladder or suction pipe
may be situated at one side of the hull, as shown upon Plate XXXVIII.
It is preferred to place the engines and boiler for actuating the bucket
ladder or suction pipe at one side of the hull, as shown at Fig. 2, Plate
XXXVIL, so as to counterbalance the weight of the shoot or tube into

VOL. V. — SECOND 8BRIBB. 2 S

302 DRKDGKU8 AND DREDQINO.

which the dredgings are discharged from the buckets or suction pipe.
The said shoot or tube (not shown on the Plates) is of the ordinary
construction, and is made to project towards the bank from the side of
the hull opposite to that whereat the engines and boiler are situated, the
shoot or pipe being stayed or supported on the hull, and allowed to over-
hang or project oyer the bank so as to discharge the dredgings at a suf-
ficient distance in from the channel, or under another arrangement the
dredgings may be discharged into any receptacle provided to receive
them. In some instances, such a receptacle is placed on the hnll itself,
and the dredgings discharged thereinto from the buckets, after which
they are mixed with water by an agitator or equivalent means, and are
thereafter forced in a liquified state, by centrifugal or other pumps through
a range of pipes Z to the point of discharge upon the banks.

Under another arrangement of the dredging apparatus, illustrated at
Figs. 3 and 4, Plate XXXVII., the hull I is pivoted upon and traversed
backwards and forwards by means of the guide rope or chain B stretched
tightly along the bank K, and cross ropes or chains F are employed to
warp the ends of the hull and end P of a suction pipe J across the face
of the work. A centrifugal pump Q is situated upon the hull I, and
agitators are arranged in the suction pipe end P, as more particularly
shown at Figs. 5 and 6, Plate XXXVII. Fig. 5 is a vertical section on
an enlarged scale of the suction pipe end P, at the line a, b, fig. 6, the
dotted lines marked J, Fig. 5, representing the position of the main suction
pipe J.

A rectangular compartment R is bolted upon each end of the portion P,
within which are agitators S composed of a series of arms or stirrers,
arranged at intervals around an axis U supported in bearings from the
sides of the compartment R, and actuated from the hull I by means of
a chain and chain pulley or other suitable gearing or mechanism. While
the pipe end P is progressing across the face of the work, the leading
agitator is caused to revolve and so stir up the silt, sand, or other soil,
which becomes mixed with surrounding water, and is drawn up the main
auction pipe J by the action of the centrifugal pump Q. The suction
pipe end P is provided with throttle valves V, V1, situated behind the
agitators, and arranged so, that when the end P is moved in the direction
of or, Figs. 5 and 6, the valve V is open, while the valve V remains closed,
whereas when the end P if moved towards y the valve V1 is opened, and the

DKEDGERS AMD DREDGING. 303

valve V elosed ; thus it will be seen that the dredgings are sucked through
only one end at a time, that is to say, through the opening that leads or ia
nearest to the bank, towards which the dredger is being drawn across the
face of the work. The suction pipe J is attached by a movable joint at or
near the centrifugal pump Q, and may be raised and lowered like an ordi-
nary bucket ladder by tackle X situated near the bows of the dredger-
After passing through the pump Q, the liquified dredgings are foroed
through a range of pipes W, and discharged upon the bank K or into any
suitable receptacle.

In dredging with the herein-before described suction pipe J, jets of
water may be used in lieu of the agitators 8, and as the pipe end P while
in operation is sunk beneath the level of the river or canal bed, the jets of
water are forced into and undermine the soil, which then falls in, becomes
mixed with the surrounding water, and is drawn up through the suction
main as herein-before described. The advantages of thus using jets of
water as an undermining or loosening agent are, that thereby the agitators
and mechanism for operating the same are supplanted by means less costly
and less liable to get out of order. When one dredging operation has
been performed by moving the hull towards one bank of the channel or
canal, the end P of the pipe J is raised, and the hull advanced the neces-
sary distance, after which the end P is again lowered into the material, and
the hull moved through an arc so as to dredge towards the opposite bank.

The figures on Plate XXXVIII. (herein-before referred to) illustrate
our improved dredger hull with the bucket ladder, or it may be the suc-
tion pipe arranged at one side of the hull instead of in a central well as
herein-before described, with reference to Figs. 1 and 2, Plate XXXVII.

The other part of our said Invention, viz., that having reference to the
utilization of the exhaust steam from the engines of the ejector pump
(when such are used) is illustrated on Plate XXXIX.

The engines for working the bucket ladder are represented in horizontal
section, the high pressure cylinder being marked A, and the low pressure
cylinder B. Steam from the boiler is led through the pipe C, and from
the pipe C a branch D feeds the steam into the engine E of the ejecting
pump F. After passing through the engine E, the steam exhausts through
the pipe O, and passes into the low pressure cylinder B of the main
engines as indicated by the arrows, or otherwise the cock g on the pipe
O is turned off, and the cock h on the branch pipe H opened, so as to

304 DRBDGSE8 AND DRBDGIHO.

lied the exhaust steam (as indicated by the dotted arrows) into the rata
chest of the high-pressure cylinder A of the main engines, which may be
thus driven entirely by the exhausts steam from the engines E of the
ejecting pump F. If, however, it should be desired not to use the exhaust
steam from the engine E, it is only necessary to cut off communication
with the main engines by means of the cocks or valves g and h, and allow
the steam to escape from the ejecting pump engines at the ship's side
through the pipe I, the cock or valve t being opened to allow the steam
to make its exit into the atmosphere.

J. W. B«

CIRCULAR BOOF IK IttON. 305

No. CCL

CIRCULAR ROOF IN IRON.

HTide Plates XL. to XLUL]

Description of a Circular Roof in Iron, with working Calculation*
and Specification.

The occurrence of a circular room, 28 J feet in diameter, part of a build-
ing of some importance, now under construction in Southern India,
gave an opportunity to apply the principle of the dome, to the iron
framing of its conoidal roof. By this, cross ties are dispensed with,
and the interior of the roof can be rendered so sightly, because appro-
priate, that a flat ceiling is not required. A roof in the form of a
conical dome may be defined in this case, to be a shell of combined
framing and terrace masonry of the figure of a solid of revolution
with a vertical axis and circular in plan. Its tendency to spread at
its base is to be resisted by the tenacity of a metal hoop or linked
aeries of bars encircling the base of the dome. To enable the roof to
be practically designed, it is necessary to know the horizontal pressure
per unit of length of arc at the base, the weight distributed over the
rib rafters ; further the minor strains, if difficulty in procuring suitable
rolled joists compels a secondary trussing of the ribs.

The calculations reduced to the simplest elements are as follows :— •

Let the roof frame-
work and covering be
considered a uniform
>B conical dome, weighing
100 lbs., or 0-0446 ton
per superficial foot, and suppose it as in the diagram, cut by a plane, at right
angles to the circle of the base. A reference may be here made to Professor
Bankine's Applied Mechanics, Fifth Edition, page 267. The data

806

CIRCULAR ROOF IK IRON.

Angle of inclination t = 22°.
Radius of the ring base = 15*25 feet.
Height Oxx = 6 feet.

Slant height of the cone BO = V62 + (15-25)* = 16*3 feet.
Weight of the roofing per superficial foot as above = 0*0446 ton.
If Px be the "whole vertical weight of the roof BOB, it is
= surface of cone BOB in feet x 0-0446 ton.
= circumference of base BB x £ slant height BO X 0*0446.
= 2* (15*25) x-yX 00446 = 34*8 tons.
The horizontal component of this downward pressure is Px cotan t =
34*8 cotan 22° = 34*8 X 2*475 = 86*1, say 86 tons. The intensity of
this single radiating thrust, reduced to per running foot of periphery of
the cone's base, is 86 -f- 2ir ( 15*25) = j-j ton per foot, all along the base

ring outwards.

The relation between the tension of a ring, and the equable pressure
radiating outwards upon that ring, is thus
determined. Let BOBB be a ring cut in
half by the transverse plane BB, and let the «..
tension at each extremity of the semi-circle <~
BOB be T. The radiating pressures Am,
Am', &c, can be resolved into a succession
of forces, one set perpendicular to BB, and
another set parallel to that axis. So also
can the forces An, An', &c, but the resolv-
ed forces, which are in this case parallel to
BB are obviously equal, opposite, and coun-
teracting, to the similarly obtained components of Am, Am', &c, conse-
quently, only the forces perpendicular to BB, of all those resolved, *w

•

effective to produce tension at the points BB. That is the single force in
the direction AO, if supposed carried along the whole diameter of the
circle with simultaneous impulse, will produce the same tension T, at B and
B, as the more numerous radial forces will, acting along the entire semi-
circumference. Or, in other words, the tension T at any point B in the
ring, will be the force in the radial direction AO per unit of periphery)
multiplied by the radius of the quadrant, to the same unit Broadly, the
tension of the ring is the product of the radiating force per unit of pri-
phery, and the radius of the circle.

PLAIE XU.

CIRCULAR ROOF IN IRON.

307

R—8'6ttmM

In the present case, therefore, if the ribs of the roof are close together,
the tension to be expected, and which must be met by the cohesion of
the circumferential ring, is 0*9 ton x 15*25 feet = 137 tons.

There are, however, 13 ribs in tbe actual roof, and the feet of each
are 7*4 feet asunder. Tbe radiating pressure is also mostly collected

at the feet of the ribs, and therefore
amounts to 0*9 x 7-4 = 6-6 tons for
each. The feet of the ribs are to be tied
by straight connections OP, OPt in the
direction of the diagram.

By Statics, R : P : : sin 154° : sin 103°

or 6 6 : P : : 0-438 : 0-974

^ 6 6 x 974 - A c .

P = -^8- = U'6t0n8'
which is the tension on each of the 13 tie bars deduced by calculation.

This is an extreme stress, not at all likely to be realized in practice,
because there are two or three considerations which mitigate the theo-
retic radial forces. The angle iron purlins bolted into five complete and
concentric circles take off some of the tension, the material of the terrace
is itself intercoherent, while a wall plate receives the dead weight of the
border of the roofing, and again, something is gained from the friction
of iron against stone bed plates.

In originally preparing the following specification, upon which, with
trifling exceptions, the ironwork of the roof was actually made, a tension
of 12 tons in each of the 18 circumferential tie bars was contemplated, and
seems sufficiently near the computed strain for a roof supporting no ceiling.

Were a set of ribs in simple rolled sections procurable, no further cal-
culation would be required for so moderate a span. As it happened, and
as generally is the case in India, a built rib of some 6ort had to be im-
provised. The form of truss chosen to strengthen the necessary length
of T-iron, is shown to scale in Fig, 2 and is that of the inverted queen-
post truss. It may be useful to give the graphic delineation of stress
as an example of that method, though a rougher approximation would
suffice in practice. The weight of the triangle HDK, shown on the
" Plan of Loading," may be taken as ^^ = ^ = 2-7 tons. G at
a third of the length of the rib, is the centre of gravity of the triangle,
and the struts BE and CF are placed in the " Section of Frame,19 with
close reference to this point. The supporting forces are by the principle

308

CIRCULAR ROOF IN IRON.

of the lever, at A = ?| x 2-7 = 1-8 tons, and at D =^§ x 2-7 =

10 lo

0*9 tons. The downward forces doe to the weight of the roof, and its
covering, may be considered proportional to the shaded segmental ares*
of Fig. 1, and are for the points A, fi, C, D, of Fig, 2 along the rib 0*8,
1-0, 0-75 and 0-15 ton, respectively. [Plate XLIIL]

The corresponding " Diagram of Stress, " Fig. 3, shows the strains along
the lines AB, AE, BE, to be by scale, respectively, 3*75, 8*5, 0 9, tons.
The lines of the Stress Diagram are colored similarly to the bars in the
" Section of Frame," Fig. 2, to facilitate reference. [Plate XL III.]

It hss thus been ascertained from the foregoing calculations, that the
tension of the ring is from 12 to 14^ tons, the compressive strain on the
rib 3} tons, the tension on the tie bars S£ tons, and the stress on the
braces, about a ton. Making due allowance for shearing strain on bolts,
areas of bolt holes, and taking the safe load on wrought-iron in tension
at 5 tons per square inch, the specification stands as follows, while the
details are drawn to scale on the plan of the roof.

Iron Roof Specification.
Bound Room.

The roof to have an iron framing composed of 18 trussed ribs, set in
shoes, distributed at eqnal distances on the top of the wall, connected at
top by a collar, and at the shoes by T-iron tie bars. The inner diame-
ter of the room is 28£ feet, and the shoes come up to this circumference.

Seen from above, the roof to have the surface of a cone, whose
at base is 30£ feet, and height 6 feet.

«*

18 T-iron rafters. — The conical
surface is to be divided into 13 equal
parts, by as many ribs or rafters.

Each rafter to be of T-iron 2±
inch top table, 3 inches deep, §-inch thick, and 16 feet long.

1 Plate Iron Collar. — An iron annular collar for
the apex, to be provided. The inclination of side to
be 22°, and to be made of f-inch best iron plate. The
opening in the centre is to be 5 inches in diameter.
The diameter at edge to be sufficient to give a
slant length of 9 inches. The collar may be made
up in three or more pieces, rivetted together with
£-inch rivets.

-** +

PLATE XLUl,

CIRCULAR ROOF IN IRON

Fif. 1.

o-ja fc» -

G B x ■''

-r5

lO ton.

.,-'■ SECTION OF FRAME.I

j' i

1 M

i ', *

(.•own.

* *'\

_4 — t— 1- ' — 1 — t — * — t-

t u.

1 1-

-+ — * — ?

* i

1 ^

IS tan

-) 7

Fl«-S.

DIAGRAM OF STRESS.

~" :

t ;

M«.W.W*.i ,

-■ - 1

1 ' 1

CIRCULAR ROOK IN IRON.

309

78 Bolts and nuls \-hch for the collar and rafters. — To this collar the
several rafters will be bolted, by £-inch screw . Fig. 1.

bolts and nuts, three a side of the J-iron raft-
er, spaced to three inch pitch.

13 Shoes compete.— The lower end of each
rafter will be rivetted to a shoe formed as fol-
lows of £-inch plate :—

Fig. 1 is this wall plate, on which a pair
of ledge plates, shown in Fig. 2, will be rivet-
ted by four {-inch rivets, so as to clamp the
feather of the y-iron rafter.

The feather of the "jMron to be secured by
'oar {-inch rivets, between the ledge plates,
and the ledge plates themselves to be rivet-
ted by similar rivets to the wall plate, Fig. 1
A cotter for the tie-rod, equal to 3fc tons
poll, to be formed at the proper place in the ledge plates.

Fig. 2.

ELEVATION

13 T-iron tie-bars with 208 three-quarter-inch bolts and ntds.— Each
wall plate or shoe will be tied to those adjoining, by T-irons 7 feet 1 inoh

VOL. V.— SECOND SERIES. 2 T

310

CIRCULAR ROOF IN IRON.

long section 4 inches by 4 inches, and |-inch thick, laid flat, and fast-
ened to the wall
plate hy four f -
inch bolts and nnts

a side, or by eight
bolts and nnts in

■♦V'+ywyy

.■■

vtw

all. at each end of the T-irons.

26 Brace bars complete—The rafters will be braced bj two com-
pression bars, placed 5 feet 7 inches from the lower end of the rafter;

and at a point 4 feet 10 inches farther
on: they will also have a tie-rod in
three pieces, of one inch diameter, joint-
ed and fitted as indicated in the plan.
The compression bars to be formed of
two plates of forgediron cnt and welded
into the annexed pattern, nowhere lew
than li inch broad, and finch thick,
laid side to side, rivetted with one met
in the middle. To hate an eye for
admission of the inch tie-rod bolt, ad
eyes for finch bolts above, which sw

to fasten the braces to the T-iron rafters. tah nt0.

13 TU-rodsmZ pieces each-^Tie-roisoi one meh^^V^

vided in three lengths for each trussed rib. They will bo
bolts andnnts; be duly enlarged at ends while the slant «*-
at the ends entering the shoes, be formed to a jib and cotter awa»»
by which they can be tightened up. The plan shows the maun
which this is arranged.

13 Purlins 180 Bolts ami Nuts i-inch diameter.
Purlins—The purlins will be of 2-inch angle iron, f-inch thick, ph*
No. Length, at points, 1' 1*, 2' J*. 2' 5* and so on, f
is 6' 10* beginning from the end of each rafter on %
13 4' 8* the wall. The lengths will therefore be, ♦
II % %• 6' 10', 5' 10', 4' 8% 8' 6*, 2' 4*, of the
5 purlins per bay contemplated. The ends of each purlin will be finish*
off by a forged flange to abut on the feather of the rib rafter, and wul
bolted to it by one finch bolt. The purlins to be curved to the nixa

CIRCULAR ROOF IN IBOM. 311

of the cone at the various points. There will thns be required 5 purlins
consisting of 13 pieces each.

Note. — The tie-bars have been made strong enough to confine the
forces transmitted bj the trussed ribs in equilibrium, but it is open to the
manufactareTB to obtain greater immunity from breaking strain, bj bolting
lengths of 2-inch angle iron below the purlins where they join the ribs
and butt against each other. The tension in the circle of the purlins is
that of the tie-bar system, reduced proportionally to the radii of one
and other.

169 quarter-inch bolt* and nub. — The purlieu will be fitted with a
wooden batten, which will be bolted to the under flange by three bolts,
j-inoh diameter, in the case of the longer purline, and two of the shorter.
The top of these battens to he flush with the top plate of the T-iron ribs.

Teak reepers. — Teak reepeis of 2£-inch broad by 1 J-inch deep scantling
to be laid at an angle of 27° with the ribs, in each triangular bay, cbev-
roned, and screwed with 2^-inch wood screws to the inlaid battens of the
purlins. The reepers will be spaced 6 inches
apart from centre to centre, to suit square
tiles of about 4}-inch sides. The reepers
to be notched £-inch on to the purlins.

Roopiron band*. — The reepers present-
ing a flat joint to each other on the top
plate of the T-iron rib, are still insufficient-
ly secured. A piece of 1^-ineh stent hoop
iron, 7 inches long, to be screwed across
the junction of every reaper, by two {-inch screws.

13 Bart over T-iron ribs. — A bar of iron, 1 j-inches broad, and \-
inch thick, to be laid along the whole length of each rib, and turned over
to grip the collar.

52 Cleate.— Each bar to be held
down by cleats of one inch by }-inch
bar iron.

104 Quarter-inch fang bolt). — The '
cleats to be secured to the T-iron
top plate, by J-ioch fang bolts.

Watt plate /or reepert.—A wall plate of teak to be laid clearof the
iron tie bars, along the extreme circumference of the base of Ihe cone,

312 CIRCULAR ROOF IM IROff.

as shown in the plan, and the ends of the reeper to be screwed to it by
If -inch wood screws.

Note. — Battens of a stronger section may be placed in similar chevraied
fashion, one foot apart from centre to centre, to suit Bengal fiat tiles.
The purlins being circular on plan, while the reepers scarcely bend, are
thrown slightly downwards, but this is little noticed from below, and
gives the impression of a cured and not polygonal surface.

Studding. — lo prevent any possibility of the tiles sliding on the chev-
roned battens, l£-inch sharp nails are to be driven bristling at points on
the battens &} feet apart.

Sloping terrace covering.— The roofing above the teak wood reepen to
be of the description known in Madras Specifications, as " Sloping Ter-
race." The covering to consist of three courses of tiles 5 inches square,
of which the first to be laid on the reepers with mortar between the joints,
the second and third courses are set in mortar. Over these three inches
of fine concrete well beaten to a uniform surface. Upon this imitation,
Italian tiles are formed, by raising ridges of fine concrete. The whole to
receive a coat of lime plaster, having 20 lbs. of goat hair allowed, and
10 9)s. of coarse molasses, per 100 cubic feet of plaster material.

Coloring.— The imitation tiling is to be colored as may be ordered, by
rubbing in pigment when rendering the plaster.

The ironwork was made by Messrs. Nicol and Co., in Bombay, costing,
delivered there Bs. 1,500. Setting up in position exclusive of carriage,
cost about Rs. 250 more, which includes the items connected with the
fitting of the reepers not necessarily supplied with the framework. The
rates for woodwork and terracing being purely local, are not of present
interest, and illustrate no general principle.

MOULDING AND DRYING 8HED6 FOR ROOFING TILKS. 813

No. CCII.

MOULDING AND DRYING SHEDS FOR ROOFING TILES.

[Vide Plate XLIV.]

By H. Bull, Esq., Assist. Engineer, Military Works, Agra.

The annexed drawings show a form of shed which is not only more con-
venient for working in, but mnch more economical than the ordinary
form.

The shed is divided into three parts. The two ends which are similar,
are for the drying, the middle chamber for the actual operation of mould-
ing. Each end is divided into four longitudinal compartments, with a
range of shelves on either side. The shelves are formed by a series of
corbellings or cornices, the offsets (or insets if there were such a term)
being shown in the drawing. The corbelling bricks shonld be partially
burnt, the rest may be kucha. The extent of corbelling in present instance
is suitable for 10" bricks. If larger bricks be available, the necessary
width of shelves may be secured in fewer layers. Thus with 12* bricks,
the projections might be made 5£" x 5£" x 5", making 15J* as shown,
this would give room for an extra shelf in each range.

It should however be noted, that the height of 5 inches below the cor-
belling should not be lessened, in order to allow room for half round
tiles, as also for a free circulation of air.

The width of shelf is suitable for a tile moulded 16", or a little
over, the flat tile will in any case overhang a little on account of the
buttons, and if the rest do the same, no harm is likely to accrue.

The roof of the centre chamber is raised above that of the two ends,

314 MOULDING AND DRYING SHBDS FOR ROOFING TILES.

so as to allow light to enter, they are connected roughly by bamboo jaff-

ries. The trasses are formed of common bailies S or 4 inches thick.

There is room in a shed of this description for moulding and drying

2,000 flat, and 2,000 half round or semi-hexagonal tiles, or allowing

five days before removal for the manufacture of 800 tiles a day, or

quarter lakh per month, or say two lakhs in a season of eight

months.

With the masonry of partly burnt and partly kacha bricks set in mnd,

and a 8* thatched roof, the cost would be about Rs. 500, or about Rs. 2-8

per 1000 on a season's manufacture.

H. B.

PLATE XLIV.

<E>orrt&$on&tntt.

To the Editor.

Dear Sib,— The question suggests itself to me (as no donbt it will hare done
to others also) with reference to the sliding gates of the Falls on the Snkkur Canal,
described in No. CXCTV., Professional Papers on Indian Engineering, (Second
Series). What are their advantages over ordinary sluice gates which wonld pass the
water under, instead of over them ?

Many disadvantages strike me in these sliding gates as compared with ordinary
sluice gates to shnt down on a level or slightly raised till j snch as —
Greater first cost
Greater difficulty in working.

Greater liability to silting and clogging by weeds or brushwood.
Difficulty of staunching, owing to pressure of water tending to force the

gate away from the face of the weir.
Greater drop of water when partially closed.
As the question is one of interest, especially to Irrigation Engineers, you may
perhaps think it worthy of such notice as may be in your power.

W. H. Price, M. InsLf C.E.t
Supdt. Kurrachee HarUnir Works.

KtTBRACHEE, )

8tA June, 1876. J

IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH. 315

No. CCIII.
IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH.

[ Vide Frontispiece and Plates XLV., XLVI. and XLVIL]

Communicated by Libut.-Col. J. O. Medley, R.E.

Voted, Bawul Pindee, May 1876.

The following report is compiled from some papers and drawings which
I brought away from the United States nearly four yean ago, and a
resumS of which I think will be interesting to many of the readers of the
Roorkee Professional Papers.

They comprise— first, the Specification of a large Iron Railway and
Road Bridge lately constructed oyer the Missouri River, at the town of
St Joseph, and which is of a pattern altogether different from any of
those ordinarily adopted in Europe or India. The advantages claimed
for it by American Engineers being greater economy, and an absence of
the objections commonly made to rivetted structures, especially in countries
liable to extreme ranges of temperature.

To the Specification of the bridge in question, is added the First Report
of the Engineer-in-Chief, Colonel Mason, by whom the bridge has since
been completed and opened for traffic, through whose kindness I obtained
these papers, and with whom I visited the works while in progress.

The accompanying Photograph and Plate No. XLV., are not drawings
of the bridge in question : but as they represent one precisely similar in
description (and I think also in length of spans) they will serve to illus-
trate these papers.

The third paper deals with the Physical Characteristics of the Missouri
River, with special reference to the training works employed to guide
the stream through the St. Joseph Bridge, which have been quite suc-
cessful, and which will be of interest, as this river is in all essential

VOL. V. — SECOND SERIES. 2 U

316 IRON BRIDGE OVER MISSOURI RIVER AT 8T. JOREPH.

points very similar to the Chenab. Its navigation is attended with the
same difficulties, which however, in this case as well as in that of the
Upper Mississippi, have not prevented the employment of steamers of
a suitable pattern, of which I sent a description some time ago, {see No.
CL., Professional Papers on Indian Engineering, Second Series.)

At a time when so much of our best Engineering talent is employed .
in bridging the great rivers of the Punjab, and in guiding their streams
with more or less success, I think it will be interesting to see the pecu-
liarities of American practice in the same direction.

J. G. M.

Specifications for an Iron Bridob over the Missouri River at St.
Joseph, designed for roth Railway and Ordinary Traffic.

Location of Bridge. — The Eastern terminus of the bridge shall be
within the present corporate limits of the city of St. Joseph, and the
Western terminus shall be in the county of Doniphan, in the State of
Kansas, opposite said city of St. Joseph. Said bridge will be located
within the limits aforesaid by the Chief Engineer of the St. Joseph
Bridge Building Company, at such point as, in his opinion, will secure
the construction of said bridge at the least cost, due regard being had to
the cost of right of way, of bridge approaches, of the bridge itself, and
the river protection.

Description of Bridge.— Number of Piers — Length of Spans. — The
bridge will consist of one pivot draw span four hundred (400) feet in
length, and three fixed spans of three hundred (800) feet each in length,
in the order in which they are named, beginning at the East abutment,
each span being measured from the centre of piers.

Description of Piers. — The bridge will rest upon structures of mason-
ry numbered and described as follows, and generally built in accordance
witfy the plans attached to, and forming a part of these specifications.

No. 1. An abutment on the East bank with curved wings.

No. 2. A pivot draw pier of the plan shown in the drawing, and cf
sufficient size under the coping to receive a circle of thirty-four (34) feet
diameter.

No. 3. A pier ten (10) feet wide and twenty -five (25) feet long under

! .

IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH. 317

the coping ; the bridge seats being arranged to receive the bearings of
the draw span on one side, and take the bearings of a two hundred and
eighty-five (285) feet span on the other.

Nos. 4 and 5. Piers nine (9) feet wide and twenty-five (25) feet long
under the coping.

No. 6. An abutmeut on the West bank with carved wings.

Height, Length and Width of Piers, — The height of the abutments
and piers shall be such that the lower side of the chords of the super-
structure shall be ten feet high in the clear above the high water of 1844,
as determined by the Engineer. The abutments and piers shall be con-
structed according to the plans and sections annexed to, and forming a
part of this contract, and after detailed drawings to be hereafter furnished
by the Engineer.

Foundations of Abutments and Piers. — No. 1. — The founda-
tions for the East abutment shall be excavated in the clay to a depth of
five feet below extreme low water, and the excavation shall be filled to a
depth of three feet with concrete, made and put in place in the manner
hereinafter described.

No. 2. — Pivot Draw Pier — shall be founded upon the rock bed of the
river on an inverted caisson, which shall be built and sunken substantially
in the same manner as were the river piers for the Illinois and St. Louis
Bridge, across the Mississippi at St. Louis.

Nos. 3, 4 and 5 — Piers — shall be founded and sunken as described for
pier No. 2.

No, 6. — West abutment. The bridge seat shall be sunken to the rock
as described for the piers, and the wings may be upon concrete founda-
tions, such as are specified for the East abutment.

Masonry. — Stone. — The work will consist of sound, durable lime,
magnesian lime, or sandstone, from such quarries as may be accepted by
the Chief Engineer, and shall be free from shakes, dry cracks, or other
imperfections.

Ashlar — Backing — Concrete — Courses to be levelled up — Sites of Cours-
es.—-The exterior of the abutments and piers shall be rock-faced ashlar,
pitched to the batter shown by the drawings, cut on the beds and joints
and backed with sound stone, fitted close to place and laid in full beds of
mortar. The backing or filling of the piers may, however, consist of
concrete, made according to the specifications for the same, each course

318 IRON BRIDGE OVER MISSOURI RIVER AT 6T. JOSEPH.

to be fully completed and levelled before the commencement of another.
At least one-third of the stone shall be over eighteen (18) inches in
height, one-third from fourteen (14) to sixteen (16) inches, and not to
exceed one-third twelve (12) inches.

Stones to be on natural bed — Beds and Joints — Vertical Joints-
Headers — Starlings— Dowelling— Bond.— All stones shall be cut to lie
on their natural beds, which are to be dressed square and true throughout
to a three-eighths (|) inch joint. The width of all beds shall be at least
one-half greater than the height of the course, and vertical joints shall
be dressed square for a distance of nine inches from the face. There
shall be headers in each course — one for every two stretchers — two and
a half feet long, in the face of the piers ; starlings to be formed of three
stones, as shown on plan. The courses of stone laid in the upper and
lower starlings and shoulders shall be dowelled together as follows :—
Through each stone, after being laid, a hole shall be drilled and contin-
ued five inches into the stone beneath ; a dowel of round iron, ten inches
in length, and one inch diameter, shall be inserted, and the interstice filled
with grout. No dowel to be placed within six inches of any joint. All
courses shall break joints with each other not less than one foot.

Starlings to be Bush-hammered— Draft line two inches.— In addition
to the cutting of beds and joints, the whole upper face of starlings be-
tween high and low water shall be bush-hammered ; also, copings of piers
and the grooves in the pivot pier for floats. On all piers there shall be
a margin draft two inches wide, chiselled on angles, and string courses,
and the courses and copings of wingwalls of abutments shall be cut ac-
cording to detailed plan.

Coping of Pivot Pier. — Coping shall be sixteen inches thick ; the co-
ping of bridge rests shall be long enough to cover the whole width of
piers, and the coping of pivot pier shall extend unbroken at least four
feet from the face, and shall be fitted to place, so that adjacent stones shall
break joints at least one foot.

Mooring Rings.— Two rings, made of one and a quarter inch round iron
and six inches clear diameter, shall be firmly secured in the down-stream
end of each pier.

Angle Irons.— On the point of the upper starling of each pier, there
■hall be bolted an angle iron in a single piece, long enough to extend from
below low water to the string course, four inches wide on each face, and

IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH. 319

one-half inch thick, and firmly secured to the pier by a wedge or bolt at
each joint in the masonry.

Mortar — how proportioned — Cement to be approved of by Engineer. — The
mortar shall consist of one-half hydraulic cement, of such brand as may
be accepted by the Chief Engineer, and one-half clean, sharp, river sand.

Pointing. — The whole work exposed to view shall have the joints picked
out and pointed with a tool.

Concrete. — How proportioned. — The concrete shall consist of two
cubic yards of limestone, broken so as to pass through a two and a half
inch ring, and screened, three and a half barrels of cement, as aforesaid,
and three and a half barrels coarse river sand, the whole to be mixed by
spreading the sand on a layer of the stone, and the cement on the sand,
pouring on water with a common watering pot, and thoroughly tinning
the whole over till each stone is covered with mortar. All concrete made
must be used immediately. That put in for foundations of abutments
must be laid in about eighteen inch courses, and each course thoroughly
rammed while fresh.

To be fresh ground — Cement condemned to be destroyed. — All cement
used shall be fresh ground and subject to frequent inspection, and any
that may, from any test applied, be found to be of inferior quality and
condemned, shall be destroyed immediately.

Draw Rests, — Cribs for — Size and description of Timber — Manner of
sinking Cribs — Pockets to be filled with Rip-rap — Cribs — how to be finish-
ed—To be lined to the batters— Drift bolts — to be dressed — Sheeting of—
Protection to Draw Span.— Cribs for upper and lower draw rests shall be
framed according to plans of 12* x 12* pine or elm sticks, in courses six
inches apart, with cross ties of oak or elm 10* x 10*, dove-tailed l£ inches
into the side courses, and locked into the centre course, the whole to be
secured by three-fourths inch square drift bolts, twenty-two inches long,
two at every intersection. These cribs shall be sunken to the bed rock on
an inverted caisson, in the same manner as described for the piers — the
pockets — or bins formed by the timber to be filled with rip-rap ; these
cribs to be carried to within one foot of low water, and be finished to a
proper height to receive the draw span, when open, and they shall be
lined to the several batters shown on plan, the outside to be constructed
of 4* x 10* oak plank, halved at the corners to form a continuous course, and
securely spiked with twelre inch drift bolts of one-half inch square iron,

820 IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH.

the inside courses to be of two inch pine or elm plank ; those running
lengthwise to be doubled, so as to level up to the outer courses ; the cross
ties to be of single two inch plank, the whole to be spiked at every cross-
ing with six inch wrought boat spike ; the whole structure above the tim-
ber cribs to be adze) off smoothly to the several batters required. The
nose of the ice breaker to be sheeted with half inch boiler plate, two feet
wide, bolted to steel rail of T form, and secured to the draw rest in the
same manner as that at the Hannibal Bridge.

Boiler 8 — General plan and character — Width letween trusses. — Be-
tween the draw rest and the first pier, there shall be fitted floats of white
pine timber, the sides composed of double chords of a Howe truss, fonr
courses high, of 12" x 12" chords. These trusses shall be twenty-sir feet
wide from out to out. The floats shall be fitted with cast-iron rollers at
each end, running in the grooves made in the masonry of the pivot pier,
and in the draw rests, with sufficient play, so that they can rise and fall
freely with the water.

Superstructure.— Z)*scri>tf0/i. — The superstructure shall be of iron,
similar in general plan and equal in character of workmanship and mate-
rials to the bridge over the Mississippi river at Hannibal.

Spans — how constructed. — The height of the girders shall be, for the
two hundred and eighty-five (285) feet spans twenty -seven (27) feet; for
the draw span twenty-seven (27) feet at the ends, and forty (40) feet at
the centre. The clear width shall be eighteen (18) feet between posts.

Contractors to furnish Working Drawings. — Before construction is com-
menced, working drawings shall be submitted to the Chief Engineer of
the Bridge Company for his approval.

Cast-iron. — All the spans shall be built entirely of cast and wrought-
iron. The cast-iron parts of the fixed spans may be the upper chords, caps
and pedestals of posts, bed plates and washers of the draw spans, the caps
and pedestals of posts and washers in bridge ; the centre spider plates,
and stiffening pieces, wheels and segments of turntable, and track under
same, and racks, pinionB and brackets for turning.

Wrought-iron — Iron to he tested — Iron to he rejected—All iron to he
finally tested. — All other parts of all the spans shall be of wrought-iron.
The wrought-iron shall be of the best quality, free from any imperfections
effecting its strength. It shall, before being used, be subject to thorough
tests in a hydraulic press, and all lots from which any selected bars shall

IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH. 321

break under a strain of fifty thousand (50,000) pounds to the square
inch shall be rejected. All the bars used in the bridge shall be subse-
quently tested to a strain of twenty thousand (20,000) pounds to the
square inch of section, and shall, while under tension, be struck with a
hammer, and if any show permanent set, or Bhow signs of imperfect weld-
ing, they are to be rejected.

Maximum tensile strain allowed on wrougkt-iron — Maximum compres-
sive strain — Maximum strain on Floor Beams. — The different parts of
the structure shall be so proportioned that a rolling load of two thousand
five hundred (2,500) pounds to the running foot, in addition to the weight
of the structure itself, and the track thereon, the latter estimated at six
hundred (600) pounds per lineal foot, shall bring on no part a greater
strain per square inch of sectional area than is shown in the following
table, to wit : — For parts which receive their full load when the entire
length of the span is loaded, 12,000 pounds. For parts which receive
their full load when three-fourths (J) of the entire length of the span is
loaded, 11,000 pounds. For parts which receive their full load when one-
half (£) of the entire length of the span is loaded, 10,000 pounds. For
parts which receive their full load when one-fourth (£) of the entire length
of the span is loaded, 9,000 pounds. For single panel systems, 8,000
pounds. The factor of safety for compressive strains shall vary simi-
larly from four (4) to six (6) as calculated by " Gordon's formula ;" and
a weight of two thousand five hundred (2,500) pounds per running foot
shall in no case strain the floor beams over eight thousand (8,000) pounds
per square inch, calculated upon the sectional area of the lower flange.

Workmanship to be of the best quality — Upper Chords to be Calli-
pered.— All the workmanship to be of the best quality. The upper
chords, if of cast-iron, shall be callipered, and if found to be one-eighth
inch less than the required thickness of metal, shall be rejected.

Greatest error allowed in length of Bars or in diameter of Boles — Con-
necting pins to be turned.— The deviation from a right line shall not ex-
ceed one-quarter inch in a twelve (12) feet column. All abutting joints shall
be planed or turned ; all pin holes in wrought-iron shall be drilled. No
bar of iron having an error in length between the pin holes of over one
thirty-second of an inch, or in the diameter of the pin holes of over one-
hundredth of an inch shall be allowed. The connecting pins shall be
turned, and no error of over one-hundredth of an inch shall be allowed.

322 IRON BRIDGE OVER MISSOURI RIVER AT 8T. JOSEPH.

Iron to be cleaned and painted— Machine work to be protected.— AH
the ironwork shall, as soon as possible after being cleaned, be painted
with one coat of oxyd of iron paint and oil. All machine work, be-
fore leaving the shop, shall be covered with a coat of white lead and
tallow.

Camber. — The fixed spans shall be built to a camber of three (3) incites.
All spans shall return to the original camber without readjustment after
having been tested.

Turntable — Platform for. — The draw span shall be provided with •
turntable of similar plan and equal in all respects to the turntable onder
the draw at Hannibal. It shall be furnished with turning gear, with
friction wheels, to be turned by levers, and so constructed, that two men
shall be able to turn the draw at right angles to the line in one and a half
(l£) minutes when there is no wind blowing. The contractor shall also
furnish a steam engine, shafting and other attachments to move and handle
the draw, of similar construction and proportional power to those in nee
at Quincy and Hannibal, also the platform on which to place the same.
Track and Flooring of Bridge.— Floor-beams — Screw-bolts— lrm
Rails— Carriage tracks. — Upon the floor beams shall be laid, for a rail-
road track, two pairs of white pine stringers, free from black or rotten knots,
shakes or any imperfections that effect durability or strength, and large
enough to size 1" X16* after being planed; placed one-half inch apart,
with blocks or keys between, and long enough to reach across two (2)
panels, breaking joints, and secured by four and three-fourths (4f ) inch
round screw bolts at each joint, or over each floor-beam. In the centre
of each panel there shall be a strut 8" x 12* with a three-fourth (}) inch
round bolt, having screw and nut on each end, and passing through both
pairs of stringers. The iron rails shall be of such form as may be here-
after chosen by the Engineer. The stringers, outside the track-stringers,
shall be four (4) in number, 6" X 14', and the ties shall be of oak 6' X 8'»
eighteen (18) feet in length, and placed twenty-two (22) inches apart
between centres. . The whole floor shall be planked with two (2) layers
of two (2) inch white or burr oak plank, laid as the Engineer may direct
The roadway shall be protected by a strong railing on each side.

Side-walks. — A side-walk, four (4) feet wide in the clear, shall be
built outside the trusses on each side of the bridge ; said side-walks to be
supported by iron brackets, properly bolted to the bridge ; to be floored

I HON BRIDOR OVBIl MISSOURI RIVBR AT AT. J08BPH. 323

with tiro (2) inch pine plank, and provided with a railing upon the enter

side.

Painting. — Portion of bridge to be painted with Mineral Painb— Por-
tion oj bridge to be painted with pure White Lead. — All the wood, track
stringers, iron floor beams, lower lateral rods, suspension bolts, washers,
&c., shall be painted with two coats of dark-brown mineral paint, from
the Brandon, Vermont, works, mixed in linseed oil. All the rest of the
ironwork of the bridge shall be painted with two coats of the best brand
" pure white lead " and linseed oil, shaded to a drab color.

Alterations or additions required by Chief Engineer, to be performed
without extra charge. — If at any time daring the construction of the
bridge, it shall be found necessary to add to the structure described ill
the above specifications, or to alter the same in order to make a complete
and permanent bridge, the additional work shall be performed and the
material furnished by the contractors without extra charge— it being the
object of this contract to provide for the complete construction of a bridge
ready for nse, the contractors furnishing all materials, labor, tools, plant
false and temporary work of every description.

Sub-contracts to be approved of, and sub-contractors to be responsible to
Chief Engineer. — No portion of the work shall be sub-let without the con-
sent of the Engineer of the Bridge Company, and it shall be a condition
of any rab-contract made, that the sub-contractor may, at any time, be
dismissed from the bridge if the work performed by him is not satisfac-
tory in progress and quality to the Engineer of the Company.

First Annual Report of thb Cbibp Engineer.

February 23th, 187%

Before reporting the present condition of the work, it may be interest-
ing to recall a few of the dates at which some of the more prominent
portions of the work were begun, and which may serve as guides to
indicate the progress made.

On the 1st of February of last year, an engineering corps was organ-
ized, and a preliminary survey begun. On the 1 5th of March following,
the first report was made, and approximate estimates for a Bridge and
Shore Protections were submitted.

Directions to prepare plans and specifications for the bridge were re-
ceived about the 20th of March. An invitation for bids upon the work
vol. v. — second series. 2 x

824 IROH BBIDGK OVER MISSOURI RIVBB AT ST. J08BP11.

according to the plans presented, was first published the 4th of May,
and the time for receiving them extended to the 10th of Jane.

On that day the contract was awarded to the Detroit Bridge and Iron
Works, and steps were immediately taken to begin the work.

In order to sink the caissons for the piers to the rock by the system
adopted (the pneumatic) a large amount of heavy and costly machinery
was necessary, and considerable time passed before it could be got to-
gether and set up ready for use ; and this time was employed by the con-
tractor in accumulating material and perfecting his arrangements.

The machinery was first started at work, sinking the west abutment,
known as Pier VI., on the 9th of November, and the caisson was safely
landed on the rock the 7th of December. Pier V., the next piece of
masonry east, touched rock the 31st of January last The exceeding
coldness of the season greatly hindered the work on both piers.

Work was begun on the Breakwaters and Shore Protections between
the bridge location and the point of land north-east of Elwood, on the
27th of September. They will be finished the 17th instant.

The condition of the work at this date is as follows : —

The West Abutment is finished. Its foundation is hard limestone
rock, sixty-one feet three inches below high water.

Pier V. is landed on the same stratum of rock that supports the West
Abutment, and its foundations is sixty-four feet two inches below high
water. All work except pointing the joints is finished below medium high
water, and seven days work with a gang of masons will complete the pier.*

In sinking Pier V. and the West Abutment, strata of sand, coarse and
fine, were passed through for thirty feet, then stiff blue clay five feet, and
lastly, a deposit of coarse gravel and boulders, through which flows a stream
of water of mean temperature, and entirely separate from that in the river.

The caisson for Pier IV. is finished and lowered from the ways upon
which it was built to the sand bed of the river, five feet below the surface
of the water. The machinery for sinking it is set up and connected with
the engines; the steam derricks with which to lay the masonry at the
proper time, are ready, and to-morrow the sand pumps will begin work, f

* March 6th, 1872. This pier is now finished.

t March 6th, 1873. The pomps were set at work on Pier IV. the day this paragraph was written,
and the suction pipe reached rock to-day. The rock will he cleaned off and concreting begun by the
10th instant. The stratum of clay was thinner, bnt that of boulders thicker than at Pier V., and the
surface of the rock is sixty-fire feet six inches below high water. The masonry is built to within six
feet of high water.

IR09 BRIDOK OVER MISSOURI RIVBR AT ST. J08KPH. 325

Enough timber is on hand to bnild the caissons for Piers II. and III.
and the draw-rests. The iron trusses with which to suspend the caissons
for Pier IL and the draw-rests while building, are well under way at
the contractor's shops, and the setting up of the caisson for the npper
draw-rest and ice-breaker will begin as soon as the ice breaks np in the
river. A large quantity of plank for the draw-rests is delivered, and
three-fifths of the rip-rap for them is piled on the bank at the east end of
the bridge. The caisson for the upper draw-rest is forty feet wide by
sixty feet long, and ita foundation will be about sixty-eight feet below
high water.

Of the dimension and backing stones to be used in the work, seven-
eighths are delivered, and seven-tenths of the quantity necessary to com-
plete, are cut, marked, piled in courses in the yard at the west end of
the bridge, and ready to be laid. The stones already cut embrace nearly
ail the bush-hammered and moulded work.

The material used for the masonry is a beautiful " magnesian " lime-
stone, weighing one hundred and forty-four pounds per cubic foot when
dry. It is brought from " White's Quarries" on spring Greek, Kansas,
near the line of the St. Joseph and Denver Railroad, one hundred and
eight miles west of the Missouri River. The thickness of the courses
varies from twenty inches to three feet ; two feet three inches being about
the average.

The severest test of the ability of this stone to endure frost without
injury has been afforded this winter. Nearly all the larger blocks, those
from which the bridge-seats and string-courses are cut, were quarried
during the excessive cold weather of last November; and the quarry-
ing Oi dimension stone was not stopped until in January, when a
sufficient quantity for the work was ready for transportation ; but not
one stone of the stratum used has been split or checked by frost
either at the quarry or in the yard. The large quarries on the Mis-
sissippi river and in Northern Illinois are usually closed about the 1st
of November, and even then sometimes a large percentage of the last
stones taken out are shattered by freezing before they can "season"
properly.

The contractor is well supplied with first class workmen, machinery,
engines, tools and boats. Within the past month he has duplicated the
power used for working the sand pumps, and put up an additional pump,

826 IRON BRIDGE OVSR MISSOURI R1V8R AT ST. J08KPB.

so (hat we are now able to sink a caisson in nearly one-half the time re-
quired for those already sunken.

All the machinery, tools and false works applicable thereto, hare been
set np and built with a view to their use in raising the superstructure
when the proper time arrives.

The arrangements in the stone yard at the west end of the bridge are
the best I have ever known for handling the same quantity of material
with rapidity, economy, and without confusion. Four thousand cubic
yards of out stone were at one time so stored and marked, that any par*
ticular course could be removed without disturbing another, and seventy
cubic yards of dimension stone, averaging one and a quarter tons weight
each, have been unloaded from the cars, and placed in the cutting yard by
the ordinary working gang in an hour.

No casualty has occurred more serious than the fall of a workman from
the false works to the ground, a distance of twenty feet, by which he was
nnfitted for labor about ten days.

A thorough examination of the work done and materials furnished, shows
that seven-tenths of the substructure is an accomplished fact.

Seven thousand two hundred and fifty cubic yards of rip-rap, all that
will be needed, is piled near the west end of the bridge, ready to be used
for facing and protecting the banks of the approaches. It is purposed
not to build these banks until after the subsidence of the spring floods.

Seven pieces of work are built to act as breakwaters, controllers of the
current in the river, and shore protections. A part of these, designated 1 ,
2, 8 and 7, on the accompanying map, (Plate XL VII.,) were only intended
as temporary, and were built more to enable the foundations of those meant
to be permanent to be properly laid. The breakwater marked 3, is about
eight hundred feet long, and was built of small cottonwood and willow brash
sunken to the bottom by weighting with sand. The brush were kept in
position in the current, before resting on the bottom, by small piles driven
by hand with a wooden maul. The channel,- much of the way across, was
from eight to eleven feet deep, with a current swifter than in any other
part of the river for two miles each way. The brush were piled about a
foot higher than low water, and covered with a layer of sand sufficient to
keep them from floating away should the water rise. When work was stop-
ped, the surface of the water at its upper end was on the channel side,
four-tenths of a foot higher than on the shore aide, and a rise of two feet

IBON BRIDGE OVER MISSOURI MVER AT ST. JOSEPH. 327

in the latter part of November entirely submerged it and nearly filled the
channel below it with sand. This structure, although intended to exercise
only a temporary influence, entirely changed the low water channel of the
river in ten days time, and it still remains complete.

The breakwater running southeasterly from the east end of the " Wa-
thena macadamized road," marked 4 on the map, (Plate XLVII.,) is two
thousand one hundred feet long, sixty feet wide at the base, thirty at medium
high water, and contains fifty-six thousand cubic yards of brush, timber
and sand, after being weighted with a wall of rip-rap averaging twelve feet
wide and three feet high, (vide section on Plate XL VI.) At the point where
this work was begun, the river hugged the Kansas shore, and was rapidly
cutting away the land. The channel, at low water, was five hundred feet
wide, and twenty feet deep, and the velocity of the current was fonr miles
per hour. The brush and timber were kept in position until sunken to the
bottom, by piles about ten feet apart, well driven with a steam pile-driver.
More than seven hundred piles were used in building the foundations.
When the work had progressed so as to materially contract the channel,
the current scoured the bottom until a depth of twenty-six feet was reach-
ed. At this time the temporary work, 3, already described, was designed
and built for the purpose of turning the current away from the larger work,
or at least of materially reducing its volume. The success of the plan
equalled our most sanguine expectations, and the main body of the river
formed a channel a thousand feet to the east of its old bed. The bottom
of this old bed was now but five feet above a stratum of stiff clay, and
but fifteen feet above the rock ; and the breakwater wa6 built across it
before time was given for it to fill with sand and mud deposits.

The second channel, when crossed, was wider and the current swifter,
but with an average depth of only ten feet. A bar about two feet under
water, near the east shore of this channel, was reached, and a mote built
of the same kind of materials used in the breakwater.

The whole width of water way in the river opposite this work is, at its
present height, less than five hundred feet, and the effect of the work has
been to give the river a new channel half a mile east of that in which it
flowed last October.

The sand bar along the east shore of the river is rapidly cutting away.
The wall of rip-rap on the breakwater is about two feet above the higher
parts of the bar opposite its easterly end, and it is expected that the first

328 IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH.

flood will cat through the bar at the low ground below Blacksnake Creek,
and find its channel in the Bayou and along the high bank of the east
shore to a point some distance below the bridge. The old channel be-
tween the breakwater and the Kansas shore, as far down as shore protec-
tions 5 and 6, will soon be filled with sand and silt deposits to a height
above ordinary floods. The breakwater is so constructed, that it may be
undermined by an impinging current until it shall sink to the bed-rock,
and still leave the rip-rap wall at nearly its present height. The current in
the river can never have a velocity sufficient to carry it away while the pre-
sent space is left between its east end and the east shore, except in the
event of a cut-off along the foot of the east bluffs immediately above the
city ; and I am confident that, even in that case, it would direct the cur-
rent and save the point of land on the Kansas shore below Elwood.

The " Shore Protection " immediately above the bridge, on the Kansas
side, commonly known as " Weaver's Dyke," marked 6 on the map, is
built substantially of like materials, and in the same manner as break-
water 4 ; but it serves a different purpose. It is about twelve hundred
feet long, and lies nearly parallel with the general course of the river,
crowding the channel gradually towards the east side. It was built in
water from twelve to fifteen feet deep, but an impinging current working
on it during two months has undermined the outer edge and allowed it to
sink, in some places to a depth of twenty-five feet without disturbing
materially the height or line of the inner or shore side. The space be-
tween it and the Kansas shore has been filled with sand deposited by the
water in the river, so that it is now dry at low water. The distance from
the lower end of this work to the east bank is a thousand feet; and I
doabt the economy of building it any further into the channel until a spring
flood shall have passed and indicated what is best to be done should more
work be thought necessary. *

• March tth, 1879. Breakwater 4 was finished, and the rip-rap all put on the l«h ulttno,
and " Weaver's Dyke " the day after. The toe oommenced moving la the river on the list* asd
broke op with arise of nine feet above low water on the Ssrd. Daring the 33rd and 94th the toe ran
with great rapidity and in large masses. Much of it was sixteen inches In one thickness, and often
two to four thicknesses had aooumalated by one sliding upon another, until some of the musts
measured five feet thick. The ice did not go oat with a continuous and uniform flow, but brsoc-
eessive gorges and breaks ; the difference of level of the surface of the water being sometimes One
feet in half a mile. During the break-up, breakwater 4 did not change position, but about two
hundred feet of the lower end of S was lifted and brought down bodily, and now lies against the
upper end of 4. On the 24th the loe gorged about three hundred feet below the end of 4, tat
against the oast bank, the gorge extending westerly nearly across the river, causing the vnok

IRON BftlDQB OVER MISSOURI RITER AT ST. JOSEPH. 829

I am confident that the next flood will furnish us with such experience
as will enable us to successfully control the river from Belmont to the
bridge line, so far as it may be in the interest of the Bridge Company to
do so, for a sum not exceeding three-fourths of that estimated in my first
report to you. Considering the success and speed with which the work
has progressed during the long and severe winter we have been laboring
in, I know of nothing in the way of completing the work as at first con-
templated.

I see nothing to suggest an increase of any estimate made in my pre-
liminary report.

On the Physical Characteristics op the Missouri River,
and the means used for directing and controlling its

Channel at St. Joseph.

U* September, 1872.

When the headwaters of the Missouri River pass the city of St.
Joseph, they have travelled 2,500 miles, and are increased by all the
streams flowing down the eastern slope of the Rocky Mountains between
the thirty-ninth and fiftieth parallels of north latitude.

The river at that point is the drainage of 413,000 square miles of
watershed, upon which there is an annual rainfall of 19£ inches.

The elevation of low water in the Missouri River at St. Joseph is
stated by " Humphreys and Abbott " to be 756 feet above tide water.
The mean elevation of its surface is, therefore, 760 feet above the tide
water. It has about 480 miles further to go before joining the Upper
Mississippi, near Alton, where it is 881 feet above the level of the sea.
Fourteen hundred miles above St. Joseph, Captain Reynolds found the
surface to be 2,194 feet above tide water.

Its average slope, therefore, for about nineteen hundred miles, is

current to strike the head of " Weaver's Dyke" with Rich force, m in a few boon to cut a channel
thlxty.foor feet deep and undermine the face of the '* Dyke." The Dyke " tamed orer " in the man-
ner expected, and remained a complete breakwater ; ao far proving the ability of the material! need
and the plan adopted to accomplish the desired purpose. The channel oppoatte the east end of 4 ia
now aix hundred and sixty feet wide, and the whole bar below the month of Blaokanake creek la
rapidly becoming narrower by the washing of the current directed towards it by breakwater 4.

The ice waa hard enough and flowed with such force is to aaw off, at the surface of the water,
elm piles sixteen inches in diameter.

330 IRON BUIDOE OVER MI880UUI RIVER AT ST. JOSEPH.

ninety-six one-hundredths of a foot per mile ; but the slope is not exactly
uniform. Between eight hundred and a thousand miles above St Joseph,
it is one and one-tenth feet; between four hundred and six hundred
miles above, it is one foot ; and from St. Joseph to the Mississippi River
it is seventy-nine one-hundredths of a foot per mile.

A careful survey for seven miles in the vicinity of St. Joseph, and
observations for a year, show an average slope of eighty-two one-hun-
dredths of a foot per mile. The difference between the slopes of the river
at these different points is so slight, compared with the great distances
between them, that for any work of a local character the engineer may
consider the average Blope, as he finds it at any point above the conflu-
ence of the Mississippi and below Fort Union, to be a constant quantity,
and hereafter in speaking of the river, I would be understood as refer-
ring to it in the vicinity of St. Joseph.

The distance between the bluffs of the Missouri in the vicinity of St.
Joseph is from four to six miles. They are generally rocky, composed of
nearly horizontal strata of limestone, sandstone, soapstone and drift, and
covered with a marl concretion sometimes called loess, supposed by some
geologists to be identical with the loess bluffs of the Rhine upon which grow
the famous vineyards. There are sometimes breaks in this rocky forma-
tion ; the city of St. Joseph is built in one about four miles wide ; but
the bluff is continuous, and a gap between the rock formation is generally
filled with loess like that which caps the bluffs above and below. During
the present geological and meteorological condition of the country, the
wanderings of the river cannot extend beyond the bluffs.

The valley between these boundaries is an alluvial plain, through which
the river cuts its way from bluff to bluff, making eight complete crossings
in a distance of thirty miles, measured in the direction of its general
course. These windings of the river leave tongues of land alternately
reaching from one bluff to within a few thousand feet of the other. In-
habitants of the towns built opposite the point of one of these tongues of
land, have usually a constant fear lest some flood may cut through the
base of the peninsula, letting the channel run along the opposite bluff
thereby leaving them miles inland. . Such cases have occurred within the
last few years ; one at Forest City, about twenty-five miles above, and one
at Hamburg, near Nebraska City. These fears have a depressing influence
upon any public work, depending for success upon the permanency of the

PLATE XLV1.

MICH WATER IM4

IROK BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH. 881

bottom lands. The citizens of St. Joseph are not without their fears ;
and although I do not say it is impossible that a cut-off should occur
opposite the city, yet its improbability is so great, that for all practical
purposes it may be considered impossible, and should the danger of a cut-
off appear at any time imminent, the engineer can avert it.

Without maps a particular description of the river and its windings may
be necessary to an understanding of the matter; and here I may explain
that all elevations given, refer to a datum line assumed one hundred feet
below the surface of the flood of 1844, the highest known to civilized
man. This line is assumed to be 676 feet above the sea.*

St. Joseph is built upon the east side of the river valley, partly on the
loess bluff and partly on the clay bottom lands, the largest part of which is
above the reach of the highest floods. Beginning three miles above the town,
the river leaves a rocky bluff on the east side and runs nearly west across
the valley to the rocky bluff at Belmont ; thence, with a sharp curve, it
returns to a loess bluff in the upper part of the town, called Prospect Hill ;
thence, with an easy curve to the south, with a radius of about 7,000 feet, it
now flows along the clay bank in front of the town for about three miles,
when, having acquired a due west course, it crosses the valley again and
strikes the bluff above Palermo, about three and a half miles south of
Belmont. Thus the river has flowed about eighteen miles to accomplish
seven of its general course.

The channel at low water, which we find to be 80, is from three to
five hundred feet wide, of very unequal depth, ranging from five to
twenty-five feet, with an average sectional area of eighteen hundred feet,
and a mean velocity of two and four-tenths miles per hour. The exceed-
ingly irregular character of the low water channel makes all measurements
of this kind at such a time very unsatisfactory.

The following measurements were made under favorable circumstances,
and I rely upon their correctness.

At 86, the sectional area was 18,126 square feet; mean velocity, two
and six-tenths per hour; discharge per second, 40,690 cubic feet. At
92, the height of ordinary floods, the sectional area is 25,450 square
feet; mean velocity, three and seventy-five one-hundredths miles per
hour; discharge per second, 189,975 cubic feet. At 92, the river is
from fifteen hundred to thirty-five hundred feet wide between its proper

• VicU " Humphrey and Abbott."
VOL. V. — SECOXD SERIES. 2 Y

882 IROH BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH.

banks. When it subsides it leaves these banks distinct, bat the space
between them is nearly filled with sand-bars.

The river at low water does not materially encroach npon the high water
banks ; but, first cutting its way through the lower bars, around accumu-
lations of driftwood and the higher bars, it makes a channel which crosses
the high water channel from bank to bank every two or three miles. It
then begins cutting away the higher bars, depositing lower ones along its
own channel, and conducting itself, on a smaller scale, as did the larger
river before it Sometimes it cuts its way through the base of a high
bar and makes a new channel against the bank opposite to that along
which it ran a few hours before, leaving the point of the bar an island.

The bottom lands appear to me to have been built up in three different
periods of time, each period depositing different materials, and under
different circumstances from either of the others.

Let us suppose the present time to belong to the third period. In
the second period, the river at average flood was from two to three miles
wide, and had an average elevation of 100. Its highest floods must
have reached 120 ; its low water channel was similar to the medium
high water of to-day.

In the first period, great floods filled the valley, and the river acoored
its rocky bed with boulders weighing tons. Its low water channel was
greater than the greatest floods of to-day. Its deposits were boulders,
gravel, coarse sand and clay. The high clay bottoms which exist to-
day have this deposit for their source.

The deposits of the second period were of fine sand and clay, and are
of great fertility. They are covered, when not cultivated, with a heavy
growth of timber, principally sycamore, oak and elm, and some of the
trees are of great size. The deposits were made in the low water chan-
nel of the first period. Their elevation is from 100 to 110.

The deposits of the third period are silt and fine sand, having in them
but a trace of day and organic matter. The silt and sand weigh from
61 to 86 lbs. per cubic foot when dry and loose, and from 74 to 97 ft*,
dry and packed. If not disturbed, in a few years they become covered
with a thick growth of weeds, cottonwood and willows. They are known
as "cottonwood bottoms." A fact explaining the growth in height of
the newer bottoms in some places is, that sand and silt brought up from
the newer bars during the winter and spring months by the winds sre

IRON BBIDOB OVER MISSOURI RIVER AT ST. JOSEPH. 833

deposited among the weeds and brash. A new bottom within two miles
of St. Joseph has grown five feet in many places within the last year
from this cause. The elevation of these bottoms is from 94 to 100.

Now, the low water of to-day has very little effect npon the deposits of
the second period, and the high water of to-day, equal to the low water
of the second period, has small effect npon the deposits of the first. The
low water of to-day is continually cutting away and changing the form
of the high water deposits, and the high water of to-day is annually
disintegrating and destroying ther deposits of the second period. The low
water of the first period sometimes cut through the base of bars making
islands. In the second period, whichever side of the island the river ran,
the opposite channel was filled with its deposits ; and it is through these
deposits that a cut-off is possible for the floods of to-day. The wander-
ings of the river of to-day are bounded, therefore, so far as cut-offs are
concerned, by the deposits of the first period.

In the tongue of land opposite St. Joseph, at the east end of which the
west abutment of the bridge now building across the Missouri River is
placed, is a spine of this material extending from the rock bluffs at
Wathena, between Belmont and Palermo, to within a mile and a half
of the oity. Evidences of struggles and failures of the river in the
second period to cut off this point are apparent in the direction of a steep
Muff of the first deposits, five to eight feet high, dividing this from the
second formation. The land composing the tongue north of this spine is
almost wholly of the second formation ; while around the east end and
along the south side, both the second and third are generally found.

Although the general direction of the river bends may be considered fix-
ed, yet among the lighter clay and sand of the second, and the light sand
of the third deposits, occupying the low water channel of the old river,
seldom less than two, and often three or four miles wide, the river wanders
at will, and no spot therein can be considered a safe foundation for an
enduring structure without artificial protection from its encroachments.
To give such protection to the west approach to the bridge, and to insure
the passage of the channel of the river through the draw at all times,
were the ends sought to be gained by building dykes and shore protection
last winter.

The bridge now building over the Missouri River at St. Joseph is located
about a mile and a quarter below Prospect Hill, nearly in the centre of

334 1R0H BRIDGE OVER MISSOURI B1VKR AT ST. JOSEPH.

the long bend in front of the city, and the embankment forming its west
approach will rest for three-fourths of a mile apon a part of the third
deposit At that distance from the river the approach reaches the first
formation. Every part of this space has been occupied by the river with-
in the past fifty years. At the time the location of the bridge was made,
the channel of the river turned directly south from a point 1,200 feet west
from Prospect Hill, and ran thence south to within half a mile of the
bridge, at which point it impinged upon the Kansas shore ; thence easterly,
parallel with the bridge about 8,500 feet to the clay bank forming the
east shore, leaving a bar a mile long and 2,000 feet wide, at an average
elevation of 90, in front of the city ; thence turning directly south, it
formed the lower part of the long bend above referred to.

The preliminary surveys for this work were made in February, 1871.
The succeeding flood in June and July was small, enduring above 90 but
eighteen days, and touching 93 only a few hours; but the action of the river on
Us west bank showed that in five years it would cut through the deposits of
the last fifty years, and reach its old westerly shore, lengthening the bar in
front of the city two miles, and leaving the bridge half a mile from its
eastern beach.

The problem was to stop the river where it was then running, and drive
it three thousand feet east and through the bar and against the clay bank
which was its eastern shore ten years ago. Work was begun for this pur-
pose in October last, and by the 1st of August following all of our objects
were accomplished.

The manner in which this work was done and the means used were as
follows :—

From a point on the west shore, three thousand feet southwesterly from
Prospect Hill, a dyke was projected into the river at right angles with the
current sb it then ran, and continued in a right line eighteen hundred feet.
This dyke inclines down-stream somewhat from a line at right angles with
the general direction of a high water channel as corrected, the upper angle
being about 70 degrees. It is called " Beard's Dyke."

Again, from a point on the west shore, 800 feet above the bridge and
8,200 feet along the shore below Beard's Dyke, another dyke was built
starting at an angle 45 degrees with the shore, and inclining down-stream,
until at a distance of a hundred feet from the bridge it has an angle of
45 degrees with the general direction of the river, and is 1,100 feet from

IRON BRIDGE OVER MISSOURI R1VBR AT ST. JOSEPH. 335

the east shore. This dyke is 1,200 feet long, and is called " Weaver's
Dyke." The point where it leaves the shore is immediately above the
point where the channel impinged upon the bank when returning, after
having been turned aside by Beard's Dyke, half built ; and except in one
particular, which I shall hereafter mention, I am satisfied with the location
of both dykes.

The woodwork of Beard's Dyke is from sixty to seventy feet wide at
the base, thirty feet wide at the top, and from twelve to thirty-six feet
deep. The lower side is vertical. This woodwork is surmounted with a
wall of rip-rap averaging twelve feet wide and three feet high, placed
three feet from the lower edge of the woodwork, (vide sections, Plate
XL VI.) The whole was built to the average height of the bar on the op-
posite side of the river.

It was known by exteneive soundings that, along the site of the dyke,
the bed rock had an elevation of from 35 to 40, and that on the top of
the rock was a layer of boulders from five to seven feet thick, covered
with a stratum of stiff clay from four to five feet thick; thence to bottom
o! channel, were the light sands of the river bed. The top of the clay is
about 35 feet below the surface at low water. I am sure, from observa-
tions made while sinking the caissons for the piers of the bridge, that the
river never scours through this layer of clay, although water soundings
show that it often reaches it.

Weaver's Dyke was built of like materials to Beard's Dyke, and over
a similar foundation ; but only to 82, except the one hundred and fifty
feet nearest shore, which is built to 96. It was designed that this dyke
should stop the action of the low water channel, and resist the efforts of
the next flood to cut a deep channel on the west side of the river, after
it should have been deflected to the west by the bar, as it surely would be
after passing the east end of Beard's Dyke ; yet the dyke was left low, so
that too great an obstruction would not be offered at once, should an
unusually high flood occur.

Beard's Dyke was put and kept in position in the water while building,
by first driving cottonwood piles about ten feet apart, within a space
thirty feet wide along the lower half of the line of the proposed dyke.
The piles were driven from ten to fifteen feet into the sand, left about
three feet above water, and then sharpened at the upper end, so that they
should not afford a foundation for the brush and timber to be put be-

836 IRON BRIDGE OVER MISSOURI RIVER AT 8T. JOSEPH.

tween and upon them. Then young cottonwood and sycamore trees, from
sixty to seventy feet long nntrimmed, were laid in parallel with the cur-
rent, tops up-stream, until the mass touched bottom, when finer brush was
laid on, and sand carted on from the shore sufficient to make a double
road for teams. This road of sand effectually packed and weighted the
whole mass, and was kept high enough to allow the passage of horses
and carts above the piles.

The first channel crossed was five hundred feet wide, and when the work
was begun, sixteen feet deep, with a velocity in the centre of four miles
per hour, and no sloughs debouched from it on the east side for a
distance of two thousand feet above. When about half way across, the
dyke obstructed the channel sufficiently to cause a difference of level in
the water above and below it of three-tenths of a foot, and the increased
velocity of the current consequent thereon, enabled it to scour the bottom
to a depth of 26 feet The river also commenced cutting into the bar
opposite, with a fair prospect of doing so as fast as we could build in so
deep and rapid a current. It showed me, however, that the dyke once
down offered a greater resistance to the current than did the sandbars, and
I permitted myself to have no doubts of final success on account of its
failure thereafter. The channel we were attempting to cross was the
principal one of three, separated by islands of sandbars ; the middle one
was about seven hundred feet wide, but too shallow to be navigated by
the ferry-boat at low- water, and the last one was a mere slough, about
three hundred feet wide, and was fast filling up.

About two thousand feet above the dyke the west channel separated
from the others. At that point it was about eight hundred feet wide,
and six or seven feet at its deepest. A dyke of a temporary character
was built across its head, which turned nearly all its waters into the oilier
channels, and greatly lessened the current at the main work, so much eo
that the washing away of the bar ahead of us ceased. This temporary
work was built of willow brush, laid between small piles driven with a
wooden maul and weighted with a road of sand. It was about fourteen
feet wide and eight hundred feet long, with its top about a foot abore
water. Before it was completed the channel scoured the bottom in some
places to a depth of from ten to eleven feet In ten days' time it changed
the navigable channel to the middle one, and remained intact until the
breaking up of the ice in February following, when about half of it *»*

PLATE XLVU.

IRON BRIDGE OVBR MISSOURI RIVER AT 8T. J08EPH. 387

torn loose and floated away. A bar with its surface at 89 now covers the
remainder. Until after a rifle of two feet in November, which nearly
filled the channel behind it with sand, it withstood the pressure of a
head of water four-tenths of a foot high.

After this dyke had succeeded in turning the channel, Beard's Dyke
was completed in the manner in which it was begun, and across the chan-
nel to an island about four hundred feet wide, with a surface of 82. Over
the island, which was but a sandbar, the dyke was built without piles.
Upon Teaching the river agaia, the dyke behind us was built to 88, the
rip-rap wall put on, and a sand road made upon it, by which to bring for-
ward material. The river was now frozen over and the current quite
sluggish. The middle channel was crossed with the dyke without having
to work in a greater depth than fourteen feet A narrow bar between
the middle and east channels, two feet under water, was reached, and the
east end of the dyke was finished by building a mole about one hundred
feet in diameter at the bottom. This was built by driving eighty piles
within the limit of its base, and piling up between and upon them brush
with the tops outward, in layers alternating with rip-rap, to the height of
the dyke. The layers of brush were about four feet thick, and of rip-rap
two. Upon the top of this work a mound of rip-rap was built to 98.
Although the river has scoured to a depth of 85 feet on the upper and
east sides of the mole, its total settlement since completion is less than
six inches.

By the time this work was completed, a deep channel, 490 feet wide,
had cut through the east channel or slough before-mentioned, and had
for ite east shore the wide bar in front of the town. It was deflected by
the bar to the west, and, reaching across the old channel, struck Weaver's
Dyke nearly at right angles at a point but a few feet from the shore end.
Weaver's Dyke, built in the same manner as Beard's Dyke, of piles,
brush, sand and rip-rap, had for its principal object the affording of
resistance to this expected attack of the river upon the west shore. The
dykes were built in the form and manner described, upon the hypothesis
that should an impigning current scour the bottom and undermine the
front of the dyke, the front part would settle and sink down until the
lowest limit of scour was reached, the back part remaining without ma-
terial change of elevation. The front of Weaver's Dyke was built in
from ten to fifteen feet of water. When the channel from the end of

338 IRON BRIDGE OVER MISSOURI RIVRR AT ST. JOSEPH.

Beard's Dyke struck it, as before-mentioned, it began scorning and letting
down the front as expected. The point of impingement of the current
gradually passed down-stream along the face of the dyke, and before the
ice broke np the whole front of the dyke had reached a depth averaging
eighteen feet below low water.

These dykes were finished about the middle of February. The rim was
then frozen oyer with ice from twelve to sixteen inches thick, with a surface
at 82$. The ice showed signs of breaking up about the 20th of February,
and on the 23rd it started, the river suddenly rising to 87. This soon
cut a channel 650 feet wide opposite the east end of Beard's Dyke. The
channel appeared a river of rolling ice, scarcely any water being risible.
Large masses were forced against and entirely over Beard's Dyke, without
injuring the wall of stone or moving any part of it. Weaver's Dyke
being low, much ice escaped over it in from four to five feet of water.

On the 24th a gorge of ice formed about four hundred feet be-
low the east end of Beard's Dyke, extending from the east shore of the
river to Weaver's Dyke. The gorge dammed the river until it stood three
feet higher above it than at the bridge, distant about half a mile below.
The gorge broke first at Weaver's Dyke, and in a few minutes the channel
was scoured to such a depth that it remained from thirty to thirty-four
feet deep along the face of the dyke after the ice was gone and soundings
could be made with the river at 81. The dyke settled down in front with
the scour — turned over, so to speak — but the wall of rip-rap remained at
nearly the same height and in the line where it was built. Beard's Dyke
across the middle channel settled about two feet This is probably as
severe a test of the ability of this form of dyke to resist and turn aside
the river as could be afforded under any circumstances.

About the 1st of June this year, the spring-flood had reached 90, al-
most entirely submerging the great bar, and flowing over Beard's Dyke
in a thin sheet, with a fall of from six to eleven inches. And now began
in earnest the work of removing the bar and making a new channel along
the clay bank of the east shore. To do this required the taking away of
at least five million cubic yards of sand. This was accomplished by the
middle of July, the flood averaging 98 meantime.

The effect of the obstruction to the current by Beard's Dyke at mis
height of the river was to make a lake of comparatively still water above
it, extending to the current of the flood then running along the bar

IROH BBIDOB OVER MISSOURI RIVBR AT ST. JOSEPH. 889

opposite Prospect HilL Through this lake ran threads of current to
supply the overflow of the dyke, strong enough to move sand along but
not to scour. The dyke standing firm, this lake was a constant force
pressing the current against the bar. This the current attacked first near
Prospect Hill, by eating into it abruptly fifty to a hundred feet, forming
what is called by river men a " pocket." The pocket once formed, it
moved down-stream, the current cutting away the bar as the mower cuts
a swath, and in a few days would pass below the dyke and disappear. But
before the first one had done its work, the second and sometimes the third
had began, and were following swiftly after. Meanwhile sand was deposit-
ed along the line between the still water and the current, and as the bar
disappeared the current still pressed against it, crowded by the still water— •
the line of deposit passed eastward, the new formed bar widened and be-
came the west boundary of the channel. This continued until the current
met the resistance offered by breakwaters constructed by M. Jeff. Thomp-
son, thirteen years ago, and still remaining effective along the east bank.
It was then where it was wanted.

I have said the pockets disappeared after passing below the end of
Beard's Dyke. The river there was thirty-five hundred feet wide, while
at the bridge it is but fourteen hundred, with the width in which it was
possible to scour narrowed by Weaver's Dyke to less than eleven hundred,
and in this space stood a pier twelve feet, and a draw-rest thirty feet wide.
The great quantity of sand taken away by the river above Beard's Dyke
most, therefore, be deposited in the still water behind it, or be carried
through the narrower space at the bridge. For some weeks after the flood
was at 93, the channel below Beard's Dyke was very uncertain. Every
pocket that came down from above made changes in the direction of the
current, which sometimes straggled over the lower end of the bar and
through the bridge, and again rushed westward over Weaver's Dyke to
the west shore. The amount of sand brought down was more than it could
at once dispose of, and a sand gorge formed opposite Weaver's Dyke, which
changed the slope of the river in half a mile from five inches to nine. Thus
the whole channel was caught in a great pocket with Weaver's Dyke on
one side, the clay banks on the other, and a sand gorge at the bridge in
front. This gorge disappeared wholly about four weeks after the formation
of the great pocket, and the channel became uniform and along the east
bank of the river. The line between the still water above Weaver's and

VOL. V. — 8KCOND SERIES. 2 Z

340 IRON BRIDGE OVER MISSOURI RIVER AT ST. JOSEPH.

below Beard's Dyke, and the current became defined ; the sand deposits
along this line began ; and, at this writing, with the water at 87, the west
boundary of the channel is as regular as the east, and is defined by a bar
out of water nearly all the way from a mile above Beard's Dyke to
the bridge.

Whenever the surface current was forced over Weaver's Dyke by the
sand gorges in the channel, the direction taken approximated to a line at
right angles with the dyke ; therefore it impinged upon the west bank
immediately in the rear of the dyke. The effect of this impingement
was to form whirlpools about two hundred feet in diameter between the
dyke and the bank, the outer rim running at the rate of ten miles per
hour, the vortex two to two and a half feet lower than the rim. These
whirlpools often developed themselves fully in fifteen minutes from their
beginning, and would cut away the bank at the rate of thirty feet in
twenty minutes. They often became in half an hour so full of drift wood,
that the water was scarcely visible. Their action upon the bank was
stopped by a revetment of trees, brush and rip-rap, followed by a double
line of piles driven parallel with the shore and about a hundred feet from
it When the sand gorges in the channel gave way, these whirlpools
ceased as quickly as they began, and the driftwood floated away down the
river. Soundings taken over the space where they existed immediately
after their disappearance, showed that they scoured to the surface of the
el ay stratum at an elevation of 45. The dyke remains as it was built
Had Weaver's Dyke been placed at right angles with the current, these
whirlpools could not have formed; and in completing the system of
dykes at the west approach, the bank of the approach will be made the
high water dyke, and a low water dyke will be built to 82 directly along
the bridge line, six hundred feet out from the west abutment, thereby
leaving Weaver's Dyke to act simply as a revetment for the west shore
above the bridge.

The influence of Beard's Dyke is such that for a mile above it, and west
of a line parallel to the present channel and passing five hundred feet
to the east of it, there is no channel with the water at 87 for a boat
drawing three feet ; while in many places, and particularly in the deep-
est of the channels obstructed by it, the sand has filled in forty feet deep,
and now completely covers the dyke from sight. The surface of the
new bar is in many places at 94. Below the dyke, sand and mud have

IRON BRIDGE OVER MISSOURI RIVER AT ST. J08EPH. 341

been deposited, so that with the river at 82, there will be a bar a mile and
a half long and half a mile wide, where flowed the river eight months ago.
The amount of deposits caused by this dyke during the flood of this
summer is more than 8,000,000 cubic yards. The bulk of the dyke as
it now stands is 56,000 cubic yards, of which 3,000 cubic yards is rip-rap,
and the rest brush and trees, with the interstices filled with sand. Its
cost, including engineering and superintendence, was $32,600, and it was
built in four months' time.

Weaver's Dyke was built at right angles to the line it was expected
the current would take after being disturbed by Beard's Dyke, and for
the purpose of resisting the current until Beard's Dyke, should have
caused the channel to run along the east shore, and entirely away from it.
Had it been built perpendicular to the channel at the time it was com-
menced, it would have failed to protect the shore, as the new channel
would have run parallel with it.

It was not expected that one flood would accomplish all that was desired,
but the extraordinary duration of the flood this summer — about 90 for
ten weeks — enabled the river to do as much as was expected of it in two
ordinary seasons. I think more water has passed this summer than during
the great flood of 1844, which, although six feet higher than the river
has been this year, was of short duration. The water now averages four
feet above that at the same time in any year of which we have any record;
and it is still so high above low water, that the whole effect of the works
cannot be seen with the eye, but is only known by careful soundings.

I have endeavoured in this paper to state as briefly as possible the pur-
pose for which the works were built, the surrounding circumstances, and
the results already attained; and although in my own mind I am satisfied
that our success is complete, I purposely avoid suggesting theories or
drawing conclusions until the present flood shall have subsided and shown

exactly what has been accomplished.

E. D. M.

342 railway nr johobb.

No. CCIV.

RAILWAY IN JOHORE.

By H. VacheRj Esq., Exec. Engineer, P. W. Dept., John.

Dated 30* March, OH.

The Independent Territory of Johore, consisting of some 20,000 sqoare
miles of the southern portion of the Malay Peninsula, covered with dense
virgin forests of more or less valuable timber, is rapidly becoming colo-
nized by the influx of Chinamen, who clear away small portions of the
forest to form gambier and pepper plantations, and settle here under the
protection and encouragement of the present Maharajah. The revenue
of the country is derived almost entirely from these Chinese settlers : a tax
being levied on all produce exported from, and on the opinm and spirits
imported into, the country. The plantations are now increasing very
much in suae and number, and the primitive method of transporting the
produce is yearly creating greater difficulties to the planters. The
Chinamen indeed are refusing to take up more land, especially as they
have to go further and further into the interior, unless proper roads are
made for them at the Maharajah's expense.

Rough bridle paths cut through the forest from the banks of the riven,
being the only present means of approach to the plantations, the whole
of the produce has to be carried on the backs of coolies (in many
cases a distance of seven or eight miles) to the nearest river, where it is
shipped in small boats drawing but little water, and conveyed thus to the
coast, where it is again transhipped into larger boats, and brought
round either to the town of Johore or that of Singapore.

After a few days rain, these small paths, from the slippery nature of
the surface soil and the absence of any attempt at drainage, are almost

RAILWAY IV J0H0RB. 848

impassable ; the rivers too, which are narrow and rapid, become on these
occasions so swollen, that it is with great difficulty the little boats can
be navigated down-stream safely. It has become therefore absolutely
necessary for the progress of the country, that proper roads of some kind
or another should be constructed without further delay. Unfortunately
there is no stone, for ballast, to be obtained in the country; and as
already mentioned, the surface soil is soft and slippery, and the few roads
that are round the town of Johore (the capital of the territory) are ter-
ribly cut up by bullock cart traffic, after two or three days rain. The
only means of procuring ballast, would be either to import stone from
one or other of the adjacent islands, or to make artificial ballast by burn*
rag the clay to be found in the country ; but both these methods would
be very expensive. A further difficulty in the way of transport arises
from the fact that there are very few cattle in the interior, and more-
over yery little grass or other plant growing without cultivation, upon
which they can be fed. No cattle will eat the rank coarse grass, known
here by the name of " callang," which rapidly covers all ground cleared
of the primeval jungle.
To meet these combined difficulties, the first idea that suggested itself

for opening up the country, was that of a light iron railway, laid with-
out ballast, and to be traversed by a wood burning locomotive, and it was
to the carrying out of this scheme that I first applied myself. Unfortu-
nately I was obliged to abandon the idea of using iron rails, on account
of their cost, and wooden rails was the alternative, on which I had to fall
bank. I then decided to make a trial mile by way of experiment, arrang-
ing that the first portion of the line should commence at the town, running
in a north westerly direction, and planned ultimately to skirt most of the
larger plantations, and terminate at the foot of a small mountainabout 8000
feet high, a distance altogether of about twenty mileB. This mountain and
the elevated ground surrounding it, is thought to be yery valuable for
special plantations. The hill would also make a good sanitarium. I
should here state that, some years ago a wooden line had already been
laid down in Johore for some miles, though it had never been of any
use, principally on account of the ground not having been properly sur-
veyed. The sharp irregular curves and the wonderfully steep gradients,
would alone have effectually prevented any locomotive from ever traver-
sing it, apart from the fact that no attempt had been made to drain the

344 RAILWAY IN JOHORE.

banks and cuttings ; the former passed over several mangrove swamps
consisting chiefly of old trees filled in with bad earth, and the latter
through some very steep hills, the cuttings of which being almost vertical,
were constantly falling in. This line had long ago been set down as a
failure, and of no value for any permanent purpose. But after giving
the matter my most careful consideration, and procuring all the informa-
tion I could, relative to existing wooden railways in Canada and elsewhere,
I came to the conclusion that, if properly constructed, a wooden line was
at least feasible.

After a variety of experiments, in order to ascertain the best form and
method of laying down the rails, a trial mile was completed, and one of
Dub's light bogie engines (kindly made over to His Highness by the
Indian Government) was placed on the track.

This locomotive ran remarkably smoothly, at a speed of about ten miles
an hour, on the wooden rails, without breaking or bending them, or even
abrading the wood in ever so slight a degree ; and, I believe, the trial
was considered by Sir Andrew Clarke and others who were present upon
the occasion, so far, a decided success. The same engine has since run
over this portion of the line about a hundred times, carrying materials, &c,
and the rails at present certainly do not look much the worse for wear.

The rails and'Bleepera are made of Johore teak, (a hard close-grained
wood, not liable to dry rot or to be attacked by white ants, known here
by the name of " Ballow"), and the former are secured to the latter by
means of wedges and trenails of the same materials. I am also con-
structing all buildings and station machinery, bridges, and culverts, and
roofs (up to thirty feet span) in the same manner, entirely without iron
in any form or shape whatever, so that the whole railway throughout,
will be made solely of wood cut from the forest, and built or laid on the
natural soil of the country.

I am now completing the survey of the projected line to the foot of
the mountain already alluded to, and pushing on with the earthwork and
culverts as fast as the means at my disposal will permit, I have promised
to send estimates and drawings, together with all necessary information,
to Sir Andrew Clarke, so soon as the first portion of the line is actually
open for traffic, and we are fully assured of its success.

H.V.

stonky's concrete-mixing machine. 345

No. CCV.

STONEY'S CONCRETE-MIXING MACHINE.

[Vide Plate XLVIIL]

On tie Manufacture of Portland Cement^ and of Concrete and Mortar.
By Bindon B. Stoney, Esq., M.A., M. Inst. C.E.

December 1871,
Of the various inventions which have been made in the arts of Construc-
tion within the last half century, there are few that can compete in im-
portance or extensive application with Portland cement, so named from
its resemblance to the well known Portland stone. For this invention
we are indebted to a bricklayer of Leeds, in Yorkshire, named Joseph
Aspdin, who took out a patent for artificial stone on the 21st of October,
1824, which he thus describes ; —

" My method of making a cement or artificial stone, for stuccoing
buildings, waterworks, cisterns, or other purpose to which it may be ap-
plicable (and which I call Portland cement) is as follows : — I take a spe-
cific quantity of limestone, such as that generally used for making or
repairing roads, and I take it from the roads after it is reduced to a
puddle or powder; but if I cannot procure a sufficient quantity of the
above from the roads, I obtain the limestone itself, and I cause the pud-
dle or powder, or the limestone, as the case may be, to be calcined. I
then take a specific quantity of argillaceous earth or elay, and mix them
with water to a state approaching impalpability, either by manual labor
or machinery. After this proceeding, I put the above mixture into a slip
pan for evaporating, either by the heat of the sun or by submitting it to
the action of fire, or steam conveyed under, or near the pan, till the water
is entirely evaporated. Then I break the said mixture into suitable lumps

846 stonby's concrete-mixing machine.

and calcine them in a fnrnace similar to a lime kiln till the carbonic acid
is entirely expelled. The mixture so calcined is to be ground, beat, or
rolled to a fine powder, and is then in a fit state for making cement or
artificial stone. The powder is to be mixed with a sufficient quantity of
water to bring it into the consistency of mortar, and thus applied to the
purposes wanted.11

The characteristic of Aspdin'a invention is, that lime and argillaceous
clay, both in a state of very minute division, are intimately mixed together
in certain proportions, then dried and calcined, and finally ground to
powder. Aspdin, however, working with the materials at his disposal,
calcined the lime in order to reduce it to a sufficiently divided state before
adding the clay, whereas the ordinary Portland cement of commerce is
now made of chalk and clay ; and as the chalk can be reduced to a fine
powder without previous calcination, the expense of double firing is saved,
and the manufacture much simplified. Besides the artificial Portland
cement (manufactured in Qreat Britain, chiefly on the banks of the Thames
and Medway, where the raw materials are abundant) there are natural
cements, largely manufactured from natural marls containing about 80
per cent, of clay, in which the combination of calcareous matter and clay
is apparently more perfect than in the artificial mixture, and might there-
fore, perhaps, lead us to expect better results. With very few (if any)
exceptions, however, the best class of artificial Portland cement is stronger
than that made from natural marls, perhaps from the composition of the
latter being variable, or from some more obscure cause — and the author
therefore confines his observations to the artificial cement made of chalk
and clay.

There are two methods of making artificial Portland cement, namely,
the wet and the dry method ; in the former the ingredients are mixed with
the aid of water, in the latter without water. The wet method is that
adopted in England. The dry method has been tried on the Continent,
but with what results the author is unable to state.

The first process in the manufacture of artificial Portland cement by
the wet method consists in the doe mixture of the clay and chalk, which
is generally effected in a circular wash-mill shaped like a huge tub, with a
central upright axis to which are attached horizontal arms carrying ver-
tical knives, the rotation of which stirs up and incorporates the materials
with water, till the whole is reduced to the consistency of cream. This

stoney's concrete-mixing machine. 847

operation is probably the most important one in the whole manufacture,
as the success of the result mainly depends on the care taken in duly
proportioning and thoroughly incorporating the chalk and clay in a very
finely-divided state. The usual proportions are from 3 to 4 parts of
chalk (according as it is the white or grey chalk), with one of clay, by
measure ; and both ingredients should be as free as possible from sand or
vegetable matter. The clay should be the alluvial clay of lakes or rivers,
in a state of minute division ; and long exposure to the air should be
avoided, as this has been found to injure its quality for artificial cement.

From the wash-mill the creamy mixture flows into tanks or reservoirs
in the open air, which have an area of several hundred square feet and
are about one yard deep. Here the washed stuff is precipitated, and the
clear water allowed to run off through suitable sluices, leaving a pasty mix-
ture, vf hich, after being partially air-dried, is cut into lumps and wheeled to
the drying ovens, from which again it passes to the kilns, which are of a
circular form, somewhat resembling an ordinary lime kiln, and worked on
the intermittent principle with coke fuel. Here again much attention is
required, for if the washed material has too large a proportion of clay, a
smaller quantity of fuel is required, and it is to be feared that this tempts
some manufacturers to overdose with clay, which generally produces a
quick-setting, but weak, cement. On the other hand, it is scarcely pos-
sible to overbrim cement in which the proportion of lime is excessive.
An excess of lime, however, renders the cement (especially if fresh from
the manufacturer,) liable to crack — no doubt from the free quicklime
throughout the mass swelling subsequently to the process of setting.
For this reason it is generally advantageous for engineering works to
keep the cement some months in store before using it, though plasterers
are said to prefer the fresh and quicker-setting cement.

The temperature of calcination should be very high, so that the cement
may agglutinate and arrive at the limit of vitrification. In this respect the
calcination of Portland cement differs essentially from that of Soman and
some other natural cements which are injured by being brought to the
verge of vitrification. Some writers think that the Bole duty of the kiln
is to expel the carbonic acid from the mixture of argillaceous matter and
lime; there can be little doubt, however, that the chemical combination
of the lime, alumina and silex is partially effected in the dry way daring
the burning, and that it is subsequently carried on and completed by the

VOL. V.— SECOND 8KBIBS. 3 A

848 stohby's conoretb-mixwg maohinb.

agency of water ; and if this be the case, the analysis of a cement stone
after calcination should show the commencement of this process, bj the
presence of silicates of lime and alumina. It should, however, be kept in
Tiew that a most essential condition of the paste in the reservoirs is that
its composition be quite homogeneous, otherwise the portions richest in
silex would fuse and form silicates which could not enter into combina-
tion with water ; and this agrees with the fact that the state of incipient
vitrification appears to be the proper limit of calcination. Highly burnt
cement is denser than ordinary cement, and density is almost invariably
an indication of strength. First-quality cement must therefore be highly
burnt ; but as the extra cost of the fuel is not more than woe to two
shillings per ton of cement, this should be no obstacle to its production
when cement of high tensile strength is required, equal to engineer's test.
The produce of the kiln, when made from properly mixed materials and
carefully burnt, will be a clinker of a dark greenish-black colour, and
reduced to about ono-half the original weight Sometimes a large pro-
portion of dnst is formed along with the semi -vitrified clinker ; this dust,
when mixed with water, will be of a bad colour and deficient in tensile
strength.

When sufficiently cool, the contents of the kiln are crushed and reduced
to small lumps and finally ground between horizontal stones, like those
used for grinding corn. If the cement is not ground sufficiently fine,
there will be a large percentage— in many oases far exceeding 1 0 per cent,
—of coarse unground particles, which are inert in the making of mortar,
and act apparently like so much additional sand. This hard granular
portion, if finely ground, will set like the rest. It is probably the very
cream of the oement, as it will bear a high tensile test if ground fine.
In the granular form, however, it does not set, and counts therefore for
nothing as cement, and is so much waste to the consumer, who thus loses
a portion, which the author has not accurately ascertained, but believes
considerably to exceed 10 out of every 100 tons which he buyB from the
manufacturer. Far too little attention has been paid to this matter of
pulverisation, for not only is the loss in weight very serious in itself, but
this useless portion is the heaviest, and probably therefore most valuable
of all the cement In America, the usual practice seema to be to grind
their oement much finer than in England, so much so that not more
than 8 per cent, of a cement should be rejected by a sieve of 6,400 meshes

stoney's concrete-mixing machine. 849

to the equate inch. It is probable, however, that the American cements,
produced from natural cement stone, are more easily ground than artificial
English Portland cement.

To enumerate briefly the properties of Portland cement, Its colour is
a stone grey, with occasionally a slightly greenish tinge. Buff-coloured
cement is almost invariably weak, and owes its colour probably to an
excess of day or to imperfect burning. The density of Portland cement
in powder varies from 1*2 to 1*4. It sets slowly, and contracts nearly
30 per cent when mixed with water. The lime is always in excess ; and
the following analysis by M. Bonnicean represents the chemical composi-
tion of cement manufactured by one of the leading London firms :—

Silica, ... ••• ... ... «•• ... ... «•§ 39U*oft

Alumina and oxide of iron, ... ... ... ••• ... 12*75

Lime, free, or combined with some carbonic acid, 4*05

Xtime in combination, ... ... ... ... ... ... 60*4?

Sulphate of lime, ... ... ... ... ... ... 1*89

100-00

The composition varies slightly, and the silica may reach 24, and the lime
in combination diminish to 54, per cent. We may, however, generally
assume that London Portland cement contains about 65 per cent, of lime
and 20 of silica, and that the remainder is chiefly alumina ; it also contains
a little oxide of iron, magnesia, and sometimes 3 per cent, of alkalies.
Indeed it is probable that all cements contain some soda and potash,
derived from the argillaceous matter.

Portland cement is especially valuable in engineering operations, as it
is less hygrometric, and it will keep longer and bear transport better than
other cements. It hardens either in air or in water; and it resists frost
and atmospheric changes well. Even after being partially set, it may be
worked up again, thohgh the practice is not recommended, and as it takes
long to set when made into mortar, it does not require any peculiar skill
on the part of the workmen. It bears a far larger burden of sand than
hydraulic lime or Roman cement, and even when much dearer per ton
than the former, it will frequently be found cheaper in reality, as it may
be mixed with from two to three times as much sand. It is extensively
applied to architectural ornamentation, and many of the finest modern
dwelling-houses in the west end of London owe their handsome appearance
to Portland cement stucco. The shipbuilder, too, largely avails himself
of Portland cement for plastering the inside of the bottoms of iron ships,

350 stohby's concrete-mixing machine.

whereby bilge water, dirt, ashes and other corroding matters are prerented
from coming into contact with the iron. In addition to its density, Port-
land cement is usually tested by tearing asunder small bricks of an T

shape— the section at the centre being 1£ inch square, that is, the area
equals 2£ square inches. The standard which the author requires is, that
the cement shall weigh 112 lbs. per bushel, equal to 87} lbs. per cubic
foot, in the dry uncompressed state of powder, and that its tensile strength
shall not be less than 350 lbs. per square inch of section after seven days'
immersion.*

MANTJFAOTUBB OF CONCRETE AND MORTAR.

We shall now proceed to consider some of the ways in which cement
is used, and first and foremost, concrete demands our attention. To un-
derstand the qualities of concrete, we should bear in mind that mortar is
a mixture of lime or cement with sand, while concrete is a mixture of
lime or cement with gravel, or with broken stone and sand ; and as gravel
is composed of sand and pebbles intermixed, we may make concrete by
mixing common mortar with pebbles or broken stone ; and this method is
sometimes adopted, though it has the disadvantage of requiring somewhat
more manipulation than the ordinary plan of mixing all the ingredients
in the dry state first, and then tempering them with water. Regarding
concrete, however, in the aspect of common mortar mixed with pebbles,
we get an adequate conception of its properties. It is, in fact, rubble
masonry, the stones of which are much smaller than in ordinary rubble
work, and the theoretic mode of making concrete would be to take a box
full of pebbles or small stones and fill in all the voids with mortar. If
we carry this idea out further, we may view mortar as a mass of sand,
u e., very small stones, with all the interstices filled up by lime or cement
paste. Practically, we require a larger proportion of mortar for concrete,
and of lime or cement paste for mortar, than this theoretic view of the
matter requires, for it is important that each pebble or grain of sand
should be completely coated with a layer of the cementing material, and
to ensure this and make amends for irregular distribution of the ingre-
dients, we put in a greater proportion of the finer materials than theory
demands. Concrete may vary in quality from coarse mortar to small

•The reader will find much netful Information on limes and cetnentein Gilmore'e K Practical Treatise
on Iimee, Hydraulic Cements and Mortars, " and in Raid on the " Manufacture of Portland Oemeak"

8T0NVY's concrete-mixing kaohinb. 851

rabble, the quality being generally determined by locality and the greater
or lees facility of obtaining suitable coarse ballast, as well as by the nature
of the work ; but whether the ballast be fine or coarse, it is very essential
that it be free from loam and organic matter*

Where machinery is not used for the manufacture of concrete, the
author finds the following the most suitable method of ensuring the
proper proportions and careful mixture of the ingredients. The ballast
is harrowed into a tray of rough deals without ends, generally of the
following dimensions : — length 20 feet, breadth 6 feet, height of sides
from 2 to 4 feet. When the tray is filled with ballast, a straight edge
is passed along its top sides, so as to reduce all the ballast to the same
level as the tray, and battens of definite thickness are then laid on the top
sides to gauge the due proportion of cement, which is spread above the
ballast— its surface being levelled with the straight edge as before, so as
to agree with the upper surface of the battens. Thus, if the tray be 8
feet high and the battens 6 inches deep, the proportion of cement to bal-
last will be 6 to 1, if the battens ?>e 4 J inches deep, 8 to 1, and so on.
Two men then face each other at one end of the tray, and turn its con-
tents over from end to end, thrusting their shovels along the floor of the
tray. By this arrangement the ingredients are mixed in the dry state
with tolerable uniformity, and the men begin again at either end, incor-
porating the mixture with water thrown on from a bucket by a third
man, in the same manner as mortar is mixed by hand. In some cases
where time presses, the two first men, after gauging the concrete roughly
with water, pass it on to tjvo other men, who give it another tossing and
then throw it into the foundation pit or wherever it may be used ; and
here it is chopped with a shovel and tamped to make it lie close, or (what
is found to answer exceedingly well) a man with heavy boots treads on
it, so as to compress it and squeeze out superfluous water which rises to
the surface and flows off.

Besides good materials, two things are requisite to make good con-
crete. 1st, Water should not be used too freely, and this requires careful
supervision, for a large addition of water diminishes the labor of turning
over the stiff mass, and therefore there is a great temptation to the work-
men to use more than is necessary. 2nd, The ingredients should be very
thoroughly incorporated, so as to make a homogeneous mass, and this
(being very hard work) is apt to be badly done unless the laborers are

852 STOVKY's OOtfCKBTE-MlXING MACHINE.

Tery carefully watched. On this account machinery is preferable to hand
labor, and several concrete mills have been invented. One of these,
which the author devised some years since and has used with very great
success indifferently as a concrete or a mortar mill, mav be described. PlaU
XLVIII. represents this machine. It consists of an open trough made
of cast or wrought-iron, 7 to 8 feet long, and 8$ fat info* The lower
portion is semi-circular in cross section, and the sides above are slightly
splayed outwards. Through the centre of the trough passes a wrought-
iron shaft, 8£ inches square, in which adjustable blades of wrought-iron
are inserted, the blades being so arranged that they may have a tendency
to screw the concrete forward as the shaft revolves. This can be adjusted
at will by turning the blades on their axes, so as to increase or diminish
their pitch. The travelling movement is also accelerated by inclining
the trough in the direction of its length, so that it may have a fall or
slope downwards towards the delivery end. The motion may be ootnma-
nicated either by a belt or gearing from a 8 H. P. engine. The method of
working is as follows : — The gravel and cement are gauged in their pro-
per proportions as already described, in a tray alongside, and two or four
men shovel them, without further mixing, into the upper end of the
mill, where the first three or four blades toss over and incorporate them
thoroughly in the dry state. Water is gradually let on from a rose
placed about one-third of the length of the trough from the upper end,
and from that to the delivery end the mixture of the three ingredients —
gravel, cement, and water-— is perfected ; so that the mortar or concrete
as it comes out is quite uniform in colour, and the mass homogeneous in
appearance. The result is exceedingly satisfactory ; the machinery is of
the simplest character ; all the operations are open to view, and the fric-
tion is far less than in the ordinary pug milL As the ends of the blades
wear down after several months1 use and become shorter, a small interval
is left all round between them and the inside of the trough. This becomes
filled with mortar, which sets hard and forms a lining to the trough, pre-
serving the latter from wear, and when the ends of the blades are renewed
after several months' use— which is simply effected by welding a short piece
of iron or steel to the ends, so as to bring them to their original length—
the coating of mortar is readily chipped off, and the trough restored to its
original condition. The great advantage of this machine oyer hand labor
consists in the facility of mixing the ingredients thoroughly and with a

SECTION OF BLADE

btonby's oohcrbtb-mixing maohinb. 858

small amount of water. It never flags, and requires little watching, whereas
laborers are apt to add an excess of water to relieve the labor of tam-
ing over the tough mass, or they add water in irregular quantities, and
unless very carefully looked after, the mixture will be imperfectly made,
and the mass resemble half-tempered mortar. Other machines have been
applied to the manufacture of concrete — such as revolving cylinders, inside
which the concrete is tumbled about till it gradually works its way to the
lower end ; and curiously constructed boxes, into which the dry materials
are first thrown through a door and afterwards sluiced with water, when
after a certain number of revolutions the box is opened and thef concrete
taken out. The author has not used this latter machine, but from its
operation being so frequently interrupted and so much time being lost in
filling and emptying it, it must necessarily be less economical than the
horizontal mill, in which the action is continuous without any interruption.
As already stated, this concrete mill is equally efficient for making
mortar. Indeed the author ventures to think it far preferable to any of
the ordinary mortar mills, especially the pan with edge runners, which
tend to grind and triturate the sand, thus reducing its sharpness and
doing useless work. In the manufacture of hydraulic mortars, the cor-
rect mode of procedure seems to be : (1), To have the lime or cement
finely ground; (2), To incorporate the sand and lime in the dry state;
(8), To temper the mixed materials as rapidly as may be with a moderate
amount of water. When the lime is not previously ground, and when
therefore lumps occasionally occur in it, the edge runners have the merit
of crashing these lumps, and thus rendering the mortar homogeneous.
In this case only does the runner mill seem to present any advantage
over the horizontal mill, while the latter is far simpler, cheaper, and more
rapid in its operation, as when properly served, it is capable of turning
out as much as 10 to 12 cubic yards of concrete or mortar per hour.

B. B. B.

Nate by Edward W. Stonby, Esq., M. Inst. CJ3., Chief Engineer' $
Office, Madras Railway.

Mrirai, Mmg We.

The above paper on Portland Cement by B. B. Stoney, M.A.,
M. Inst C.E., contains drawings and descriptions of a most simple and
efficient concrete mixer, which could be easily manufactured out here
in India.

854 stonby'b conoretb-miximg machine.

These machines have been regularly used for several years on the Port
of Dublin Works, where very extensive concrete works are being done,
and I have seen them at work, — they are so simple, open to view, Ac.,
that they give no trouble and work beautifully.

This description should be of considerable interest and use to Engi-
neers engaged in concrete works in this country.

The machine could be driven by bullock gear for small works.

EL W. 8.

CONSTRUCTION OF LIGHTNING CONDUCTORS. 355

No. CCVL

CONSTRUCTION OP LIGHTNING CONDUCTORS.

By Dr. R. J. Mann, M.D., F.R.A.S.

[Read before the Meteorological Society, 9th May, 1875.]

Thbrb are certain principles bearing practically upon the efficient pro-
tection of buildings from injury by lightning, which are well ascertained,
and which are now looked npon as established facts in electrical science.
Thns, for instance, it is well known that the primary aim of the Architect
or Engineer who attaches a lightning conductor to any building, is to
famish a path for the electrical discharge that shall afford the least pos-
sible resistance to its passage, or, in another form of expression, a ready
way for the escape of the pent-up force. This end is gained— first, by
employing a metal that is in itself a good conductor of electrical action,
and secondly, by taking care that the dimension of the metallic conduc-
tor, whether it has the form of strip, rod, or rope, is ample for the work
that it has to do ; that there is large and free communication between it
and the earth, which is the great electrical reserroir of nature; and that
there is no break of metallic continuity, no obstruction to the free and
unimpeded movement of the discharge anywhere.

When the question of the character and size of the lightning rod, which
may be expected to fulfil these conditions satisfactorily, was examined by
the French electricians in the year 1823, and still more recently in 1864,
it was held that a quadrangular iron bar, three-quarters of an inch in
diameter, was sufficient in conducting power for all purposes. Since that
time, ropes of metallic wire have pretty well superseded the employment
of solid bars, on account of the greater facility with which they can be
applied to objects of irregular form, and on account of the readiness with

VOL. V. — 6KCOND SERIES. 3 B

356 COHSTRUCTION OF LIGHTMNO GONDUOTOB8.

which they can be constructed, in unbroken continuity, to any length.
Copper is also very generally need in preference to iron, because of its
superior transmitting power, and of its greater immunity from corrosire
oxidation when exposed in moist air. In reality, however, the selection
of iron or copper is not of material importance, if the surface, in the case
where iron is employed, be protected from oxidation by a coating of zincr
and if the size of the rope or bar be sufficiently great to compensate for
the inferiority of its transmitting power. That is to say, a large rope
or bar of iron conducts quite as freely and well as a small rope or bar of
copper. Copper is about fire times as good a conductor of electrical force
as iron, an iron rope or rod, to perform the same work, should, therefore,
have at least a sectional area five times as large as a copper rod or rope.
It must, however, always be borne in mind that the resistance of a metal
conductor increases with its length, and that, therefore, for the protection
of lofty buildings, larger ropes or rods are required than need be employed
for lower structures. The facility of electrical transmission in any conduc-
tor is practically in the exact ratio of the coefficient of the condoctibility
of the metal, multiplied by the section of the rod, and divided by its length.

The French electricians of the present day adopt copper wire ropes of
from four-tenths to eight-tenths of an inch for each 82 feet of height.
Mons. R. Francisqne Michel, who iB at the present time the scientific
adviser of the French Governmental Department of works in such matters,
seems to consider a rope of galvanized iron wire, eight-tenths of an inch
in diameter, to be ample for most purposes. Mr. Faulkner, of Manches-
ter, has recently used in the protection of St. Paul's Cathedral, which,
even within the last three years, was found to be in very faulty state in
regard to its safety from lightning, a copper wire rope, half an inch ia
diameter, which is made of eight strands of one-tenth of an inch copper
wire coiled round a core of seven smaller copper wires of about one-half
that diameter. This copper rope weighs six ounces and three-quarters
to the foot. Eight of these ropes, in the case of St. Paul's, have been
brought down from the golden cross, which surmounts the dome, to the
ground : the element of great height in this instance has, therefore, been
amply provided for.

Mr. Faulkner frequently uses, for the connection of large iron pillars
and other metallic masses in large factories, and for earth-contacts with
the pillars, large bands of solid copper of No. 11 Birmingham iron wire

CONSTRUCTION OF LIGHTNING CONDUCTORS. 857

gauge, and four inches broad, and which weigh 1 fib. 18 ounces to the foot.
Messrs. Sanderson and Proctor, of Hnddersfield, manufacture a very con-
venient kind of copper tape for lightning conductors, which is three-
quarters of an inch wide, and an eighth of an inch thick, which has even
more flexibility than wire rope, and which can be made in continuous
stretches of great length with equal facility. Strips have the advantage
over rope in one particular. They are free from the strain which is prone
to be set up in the molecular condition of rope under the operation of
twisting. Mr. Gray, of Limehouse, refers to some instances in which
copper rope has seemed to have been rendered incompetent for its con-
ducting work by the influence of the strain.

There is one condition in the arrangement of a lightning conductor
which is even more important than the conducting capacity of the rope or
rod ; namely, the freedom of its electrical communication with the earth.
In the case of a rain pipe, it would be of no practical utility to put up a
pipe of four inches diameter, if the hole below for the escape of the water
were contracted to an aperture of a quarter of an inch. Yet the arrange-
ments that are very commonly made, in what is termed protecting a house
from lightning, are even infinitely worse than this. It is quite a common
occurrence to find lightning conductors, with ten thousand times less out-
flow for the electrical force beneath, than there is passage for it through
the main channel of the rod. The result in such cases is that the entire
conductor is reduced in vertical effectiveness to the proportions of its
weakest or smallest part ; that is, it is made inefficacious entirely for the
work that it is expected to do. This practical evil is also increased in
an enormous degree from the unfortunate fact that lightning conductors
tend continually to get less and less efficacious in their earth-contacts
from natural causes. The metallic surfaces below the ground become
covered over with thick crusts of oxidation, and are eaten away from
comb'ned chemical and electrolytic agency, and as this occurs, they afford
no visible or palpable indication of the growing defect until grave mis*
chief happens from some chance lightning stroke. Faulty earth-contacts
are unquestionably the most frequent cause of failure of lightning rods to
perform the office for which they are designed.

MM. Pouillet and Ed. Becqnerel have entered upon some very labori-
ous and exact experiments to determine the relative capacities of pure
water and metallic copper to conduct an electrical current or discharge ;

358 COWBTBtfOTIOH OF LIGHTNING CONDUCTORS.

and they have arrived at the conclusion that metallic copper conducts
6,754 million times more readily than pure water. In accordance with
this deduction, a copper rod/ if it were made for electrical purposes
to terminate in an earth-contact of pure water, would need to have
a surface exposed to the water 6,754 million times larger than the
sectional area of the rod. This theoretical conclusion is, however,
materially affected by the fact that it is not pure water that is en-
countered in the pores of the moist ground. It is water that contains
various saline principles and other matters in solution; and these dis-
solved matters increase its power of electrical transmission enormously.
From this cause, and from some other correlative influences, it has been
found that if 1,200 square yards of actual contact with moist earth is
provided for a copper rope or rod eight-tenths of an inch across, that
proves to be an ample allowance for all purposes. But even that, it
will be observed is somewhat of a formidable task. It means an actual
surface of contact 34 yards across in both directions. The most ready
and immediate means by which this large earth-contact can be made in
towns is by effecting an intimate metallic connection between the light-
ning rope and the metallic pipes of the water 6upply. Where this
cannot be done, other expedients have to be adopted. The French
electricians have recently contrived a stout harrow of galvanised iron
with down hanging teeth for the accomplishment of their earth-contacts;
and they pack this harrow away into some moist part of the ground,
surrounding it carefully with a mass of broken coke. M. Oalland, a
French Electrical Engineer of some distinction, has a refinement even
upon this. He anchors his rope in an underground basket of netted
wire by means of a kind of coarse iron grapnel, with four up-turned and
four down-turned teeth, and he packs round the grapnel within the wire
basket with broken coke. The coke is a very admirable agent for estab-
lishing the electrical communication between the earth and the rope or
rod on account of its great porosity. It is immediately saturated with
moisturey when it is placed in moist earth. M. Calland has ascertained
that two bushels and eight- tenths of porous coke afford the 1,200 square
yards of contact-surface that are required. The alternative, when neither
the harrow nor the grapnel are employed, is to make a five-inch bore
down 20 feet into the moist earth ; to insert into this bore the lower end of
the conductor, whether rod or rope, and then to ram it well reond with

CONSTRUCTION OF LIGHTNING CONDUCTORS. 359

broken coke until the bore is filled. Horizontal trenches opened ont in the
actually moist ground, and with the end of the conductor distributed into
them, with a surrounding packing of coke, answer very much the same
purpose. Messrs. Gray and Son, of Limehouse, employ for their earth-
contacts two divergent trenches of this character, each about 16 feet long.

My friend, Dr. Williams, who is a keen observer of most matters that
concern atmospheric meteorology, tells me that in the neighbourhood of
Gais, near to St. Gall and Appenzel, the beginning of the Highlands
immediately to the south-west of Lake Constance, there are from two to
eight lightning conductors to every house, and there are, nevertheless,
conflagrations from the discharge of lightning upon the houses every
season. The lightning conductors are obviously inefficient for the work
which they are intended to perform, and Dr. Williams ascribes this to the
insufficiency of the earth-contacts. The soil consists principally of porous
limestones and conglomerates, which dry very rapidly ; and in all proba-
bility the lightning rods are just placed in contact with the dry rock, with-
out any attempt to compensate the dryness by special contrivances for
enlarging the surface of communication. The rods are consequently very
much in the condition of the well-known case of the Lighthouse at Genoa,
in which the lightning conductor was terminated below in a stone rain-
water cistern especially constructed to keep out the infiltration of the sea,
or of my own instance of the lightning rod of a church tower which was
packed away at the bottom in the inside of a glass bottle.

Perhaps the most important advance that has been made by electrical
science in recent days in regard to the establishment of efficient earth-
contacts for lightning rods, is the assertion of the principle that the
efficiency of the earth- contacts must be in all cases tested by actual
experimental proof. The circumstances upon which the free transmission
of the electrical force depend are so complex and varied, that it is only
when a direct investigation of the freedom of the transmission has been
made in any individual case that all the requirements of exact science can
be held to have been efficiently fulfilled ; and it fortunately happens that
there is an instrument in the hands of scientific men, which enables this
crucial test of efficiency to be very readily applied. This instrument is
the galvanometer. The needle of a galvanometer is deflected by an elec-
trical current passing through the coil of the wire to an extent which
indicates the readiness with which the current is transmitted thcengh

360 CONSTRUCTION OF LIGHTNING CONDUCTORS.

the coil. Now, if both terminals of the wire of a galvanometer are placed
in direct communication with each other, through short circuit, with a
Leclanche" Battery of a couple of cells coupled up into the circuit, and the
degree of the deflection of the magnetic needle under this circumstance of
free and entirely open transmission, be noted, this at once becomes a
standard with which any less free transmission of the current can be com-
pared. If, then, all other circumstances being the same, the short circuit
is broken, and one terminal of the wire of the galvanometer is placed
in communication with a gas pipe unquestionably in unimpeded commu-
nication with the earth, and the other terminal is placed in electrical
communication with the rope or rod of a lightning conductor, the circuit
in such case has to be completed through the earth-contact of the con-
ductor, instead of through the shorter route, and if there is any increase
of resistance or impediment there, this at once becomes manifest in the
deflection of the needle of the galvanometer being to that extent less than
it was in the previous arrangement with that circuit. If the earth-contact
of the lightning rod is sufficiently open and perfect, the deflection of the
galvanometer is very nearly the same in both instances. In the arrange-
ments carried out within the last two years for the protection of St Paul's
by Mr. Faulkner, every large mass of metal in the construction of the
building was brought in succession into metallic connection with the
main track of the lightning conductor, and was never left, in any instance,
until the indications of the galvanometer manifested that the earth-contact
from it was virtually open and free, at least to within one or two degrees
of the deflection of the needle. The copper ropes terminate with carefully
rivetted attachments in copper plates, which are pegged into the moist earth
of the sewers beneath the streets surrounding the Cathedral.

Mr. Spiller has drawn attention to the very common occurrence of the
rapid destruction of a copper lightning conductor attached to a chimney-
stack through the influence of the sulphurous vapours emitted from the
burning coal ; and has suggested that nickel plating may afford an effici-
ent remedy to the evil, as he finds there is not the slightest action upon
a nickel-plated surface after it has been buried for weeks in powdered
sulphur. It unfortunately happens, however, that the conducting power
of nickel is very low in comparison with that of copper, lower even than
that of platinum. If silver be taken as the standard of conductibility,
and be estimated as 100, then the relative value of the conducting power

CONSTRUCTION OF LIGHTNING CONDUCTORS. 861

of copper platinum and nickel is— copper, 91*4; platinmn, 8*1; and
nickel, 7-7. The relative resistance of the same metals to the transmission
of the electric force, if silver be taken as a standard at 100, are respec-
tivly: — copper, 109*8; platinum, 1243*4; nickel, 1428. Protection from
snch fames would probably be quite efficiently provided if the copper
conductor were carefully enclosed within a leaden tnbe soldered over the
conductor at its extremities, wherever damage from this cause has to be
apprehended. This plan is adopted by the French electricians very satis-
factorily in establishing earth-contacts, wherever there are ammoniacal
vapours present in the ground. Messrs. Sanderson and Proctor state that
they are introducing ebonite tubes for the same purpose.

Whenever different lengths of a lightning conductor have to be joined,
this requries to be done with the utmost nicety and care. If there is any
break in the metallic continuity, it materially increases the resistance, and
impairs the efficiency of the conductor. In the case of metallic ropes, the
wires are generally untwisted and spliced together where the contact has
to be made, and the joint is afterwards dipped into melted solder. Mr.
Faulkner effects the union of his broad copper straps by covering the
joint with an overlapping plate, and screwing the whole firmly together
by screws passed through the thickness of the overlapping parts. M.
Francisque Michel, in renovating and perfecting the attachment of many
of the impaired lightning conductors furnished to the public monuments
in Paris, has adopted the ingenious expedient of screwing on washers of
soft lead very firmly between the contiguous surfaces of the interrupted
joints, and then covering the whole joint up with a coating of melted
solder.

The instructions of the French Academie des Sciences, issued by
Pouillet in 1854, directed that the lightning conductor should be termi-
nated above by a solid rod, if of iron, two inches and a quarter in diameter,
carried up from 15 to 30 feet above the highest point of the building to be
protected. The reason for this increase in the dimension of the rod at
its upper extremity is found in the well-known fact that the largest dis-
ruptive effort is exerted, when an electrical discharge occurs through a
line of conducting metal, at the two opposite extremities of the conductor.
On this account, both the earth-contact and the upper termination must
be strengthened to meet this strain. When points are employed at the
upper termination of a lightning conductor, however, the need for this

362 CONSTRUCTION OF LIGHTNING COHDUCTOBfl.

increased sise is, to a considerable extent, obviated, in consequence of the
point setting np a continuous stream of low tension. The real value of
the point indeed is due to this peculiarity. A well arranged lightning
conductor, famished with efficient terminal points, discharges or saturate*
a thunder cloud at a great distance silently, and almost certainly prevents
any actual disruptive discharge, or flash, of the lightning. The immediate
consequence of this is, that the electrical discharge passing through the
conductor never reaches the condition of high tension. It flows off in a
gentle stream, which never at any time has expansive energy enough to
burst out from the channel provided for its conveyance, or to produce, by
induction, return shocks, or other sudden and violent effects of an induc-
tive character. The blunt conductor, struck by a true flash of lightning,
on the other hand, although it may convey the discharge to the ground,
is at the instant of the passage, filled with force of such high tension, and
of such energetic expansion that it is ready to leap forth from the con-
ductor to any body conveniently near, upon the slightest excuse or pro-
vocation. A living peroon may embrace a lightning rod discharging a
thunder cloud through a point without knowing anything about the matter;
but he could not do the same thing with a blunt lightning conductor
discharging a thunder cloud without incurring the greatest personal
danger. There are various simple experiments by which this par-
ticular power of the point may be familiarly illustrated; but a very
remarkable and telling instance of this power has just been communicated
to me by Mr. F. O. Smith, in allusion to some remarks I had printed on
the subject. Mr. Smith was engaged in the August of 1865 in ascending
the Linguard Mountain from Pontrisina in the Engadine, with three
companions, and was caught during the ascent in bad weather. He
nevertheless reached the summit, which is a sharp, narrow ridge, shaped
like the back of a horse, and 11,000 feet above the sea. At one end of
the ridge there is a flag-staff tipped with an iron point, and at the op-
posite end an observation disc of the same height, covered with an iron
hood. When he stood upon this ridge there was nothing visible round
but grey mist and falling snow, and almost immediately the otherwise
death-like stillness of the gloomy spot was broken by a strange intermit-
ting noise, resembling the rattling of hailstones against the panes of a
window. A careful investigation of ih» cause of this noise soon made it
apparent that it proceeded from the flag-staff, and that it was sometimes

CONSTRUCTION OF LIGHTNING CONDUCTORS. 363

at the base, then quivering all through from top to bottom, now loud,
now softy but never ceasing for a moment The rattling was in reality
due to the passage of a continuous stream of electrical discharge from
the cloud, in which the summit of the mountain was wrapped down the
flag-staff. After a little time the entire party held up the pointed ends of
their alpeo-stocks into the air, and immediately the same rattling noise
appeared in each, and the electrical discharge was felt by each individual
passing through them, and causing a throbbing in the temples and a ting-
ling in the finger ends. The noise was still going on vigorously when Mr.
Smith left the summit after a sojourn upon it of three-quarters of an
hour. Hie broad iron hood and flat observation plate in the meantime
were perfectly untouched by the discharge.

Some distinguished electricians of a past age maintained that it was of
do importance whatever to place a sharp point upon the top of a lightning
rod, because even a metallic ball some inches across is virtually a point to
a thunder cloud on account of its being so very much smaller than the
cloud. This, however, is certainly a mistake. Mons. Gavarret, Pro-
fessor of Statural Philosophy to the Faculty of Medicine at Paris, in
some very beautiful experiments, has shown that the tension or strik>
ing force, which can be produced in the prime conductor of an electrical
machine, is progressively diminished as longer and sharper points are
brought into operation in the neighbourhood, to draw off the charge.
The points are placed a little distance away from the conductor, and are
attached to an earth wire. If a slender and sharp point exerts more
exhausting influences over the charged conductor than a coarse and blunt
one, it is perfectly clear that a point must exert a stronger influence over
a charged cloud than an unsharpened rod or a ball.

Platinum has been very generally recommended for the construction of
the points of lightning rods, on account of it6 property of remaining sharp
and uncorroded when left freely exposed to the moist air, and even when
frequently transmitting streams of electrical discharge. Platinum is one
of the most difficult metals to melt, and is comparatively indifferent
to the chemical attractions of oxygen. But, on the other hand, it is
unfortunately not a good conductor of electricity. It has 12 times
leas conducting power than silver, and 11 times less conducting power
than copper. The employment of platinum as the upper terminal of a
lightning conductor consequently increases the resistance of the rod, on

VOL. V.— SECOND 8XR1BB. 3 C

864 CONSTRUCTION OF LIGHTNING CONDUCTORS.

the ground of constituent materials, at the same time that it reduces the
resistance by figure when in the pointed form. Mons. Fancisque Michel,
the Superintendent of the Electrical Department of the Public Works at
Paris, has consequently superseded platinum by an alloy of copper and
silver, which contains 165 parts of copper to 835 parts of silver. This
form of point keeps its sharpness very well, and conducts quite as freely
as the copper conductor. The points are about two inches long, and are
shaped off to a cone, having an angle of from seven to ten degrees.
They are so contrived that they can be screwed firmly home into a socket
provided for them at the end of the copper rod. Plain copper points,
however, answer all purposes very well if they are examined from time
to time, and kept fairly sharp and clean, and especially when several
points are used in the place of one pointed terminal. The multiple point
is gradually making its way, as it thoroughly deserves to do, into general
use, and into the confidence of scientific men. Various forms of it have
been devised ; but all that is really practically needed is, that the conductor
shall be branched out above, and forked out in all directions, so that
there shall be points everywhere projecting beyond the cone of protection
recognised by the electrician, which, to make the protection entirely
reliable, should have a perpendicular height at the apex of something
like half the breadth of the building. Wherever the building extends
beyond, or even approaches near to the limits of this conical surface,
there should be a point pushed out a little further still, and at the
same time connected metallically with the general stem of the conductor.
H. Melsens, the Belgian electrician, who has recently perfected the pro-
tection of the Hotel de Ville in Brussels, has left that large building
literally bristling over with points. There are as many as 228 copper
points and 86 iron points comprised within this system of defence, and it
is quite impossible to conceive any more effectual arrangement of the up-
per terminals of a lightning conductor.

M. Melsens in his practice adopts the generally accepted plan of
connecting all large metallic masses contained within the building with
the main stretch of the conductor; but he does this after a fashion
somewhat peculiar to himself. He makes the connection by means of
closed circuits, that is, he attaches the metallic mass to the lightning rod
by two distinct metallic strands, carried to two distinct points of the rod.
He considers that in this way the protection against inductive disturbance

CONSTRUCTION OF LIGHTNING CONDUCTORS. 365

and return shocks is more absolute and complete, and he, no doubt, has
in support of his view the authority of Professor Zenger, of Prague,
who has devised some experiments, which he conceives to demonstrate
that the best of all protectors is a circular segment of metal carried
transversely overhead across the area containing structures that have to
be defended. M. Francisque Michel, and most of our own electrical
Engineers, in the meantime, adhere to the practice of connecting all large
masses of metal in a building with the lightning conductor by a single
metallic strand.

M. Calland, a French electrician, who has recently printed an interest-
ing book on the lightning conductor, objects strongly to this practice of
connecting masses of metal entering into the construction of the build-
ing with the lightning rod, and also insists upon the insulation of the
rod itself from the masonry of the building by non-conducting supports,
such as are used with telegraph wires — an expedient that has been for
some time almost universally abandoned, so far as the lightning rod is con-
cerned. M. Calland's reason for this course is perfectly intelligible. He
contends that metallic masses employed in the ordinary work of construc-
tion are frequently placed where living people have occasional access to
them, as in the instance of an iron balcony projecting in front of a
French window ; and that where this is the case, the danger of such
people is materially increased if the metal work or balcony is connected
with the conductor, because then the living body is apt to form a step-
ping-stone of approach, if the lightning passes that way to the system of
the conductor. M. Calland argues, and so far argues correctly, that the
lightning rod is very much more likely to bo struck than the masonry or
woodwork of a building, and that any metallic appendage, such as an
iron balcony, stands in the category of the conductor when it is connect-
ed with it, and in that of the masonry when it is not so connected. Thus
a living person placed near to a balcony, that is connected with the rod,
is, in the same degree, more likely to be struck by a discharge than a
person placed near a balcony that is without such metallic connection.
The practical inference is, that metallic masses in a building should al-
ways be metallically coupled up with the lightning conductor when they
are so situated that they are not liable to have living persons near to
them during the prevalence of a storm, and that they should be left un-
attached to the conductor when they are so situated as to be of ready

366 CONSTRUCTION OF LIGHTNING CONDUCTORS.

access to persons inhabiting the buildings. It should, however, be also
clearly understood that this connection or non-connection of incidental
masseB of metal is of no practical moment whatever when a building
comprising them has a really efficient lightning conductor, with ample
earth-contacts, and an abundant supply of well arranged points dominat-
ing its entire mass. It is only when a conductor is in so imperfect a
state, or is so badly planned, that subordinate masses of metal can act as
recipients, and feeders of the discharge through the earth-contacts, that
the question of connection of such masses with the conductor becomes
one of practical moment. A properly planned lightning conductor should
coyer and afford absolute protection to all that a house comprises and
.contains, and should render a lightning stroke to any subordinate part
of the struoture a virtual impossibilty. M. Calland seems to insist upon
the support of the lightning rod by insulating attachments, principally
because it is a part of his general principle of avoiding electrical connec-
tion with the structures of the building. My own impression upon this point,
however, is that it is certainly a work of superfluity to take any trouble about
such insulation. In a considerable experience with lightning conductors,
• in which insulation has never been adopted, I have never known any case
of injury, even of most trifling kind, from this cause. Messrs. Gray
and Son have met with one curious and notable case, in which a copper
rope, which had been grasped by insulating conductors, had been broken
and disintegrated wherever the rope had been connected with an insulator.
This result, however, was most probably due to some mechanical cause,
affecting the molecular condition of the strained wires at those points.

The insulation of the rod certainly promotes, rather than prevents, the
production of the incidental sympathetic discharges, which are known as
" return shocks." These " return shocks " are entirely due to the opera-
tion of induction. When a lightning rod is placed in a state of high
electrical tension in consequence of being under the influence of a neigh-
bouring storm cloud, it immediately calls up induotively a similar state of
electrical disturbance and tension in material masses that are near to it,
but separated from it by a non-conducting space or gap. When the
storm cloud is suddenly discharged under such circumstances, whether
through the conductor, or by some other route, the tension in the con-
ductor is instantaneously relieved, and at the same moment all secondary
tensions produced by it are also terminated in the same instantaneous

CONSTRUCTION OF LIGHTNING CONDUCTORS. 367

fashion. The secondary tensions, under these circumstances, are very apt
to leap to the earth through more or less imperfectly conducting routes of
their own improvising, and to produce some mechanical disruption in doing
so. The proper and effective cure for such incidental disturbances is the
employment of such a system of pointed terminals as renders the production
of any state of high electrical tension in the conductor impracticable.

The " tall-boys," or metallic chimney-pots, so commonly employed in
towns to increase the force of the chimney draughts, may be eminent
causes of danger in houses not furnished with lightning rods, because the
column of heated air ascending to them from a burning fire through the
chimney is a conducting route of considerably diminished resistance as
far as the fire grate ; but it is -a conducting route that generally termi-
nates there, and that, therefore, is very apt to lead a lightning discharge to
the earth through the intermediate steps of living persons inhabiting the
room. The " tall-boy," on the other hand forms a very ready base for
the support of an efficient point, if it has the conducting route from it to
the earth completed by a competent rod earth-contact. Messrs. Gray
and Son, of Limehouse, speak of one case in which a large and lofty
chimney-shaft of brickwork was materially damaged by a lightning
stroke, although the chimney had an apparently good lightning rod fixed
at one side of the shaft. The point of the chimney at which the electric
discharge came into communication with the ascending column of heated
air was, in this instance, four feet and a half nearer to the discharging
cloud than to the lightning rod. The discharge in this case found the
column of heated air, the surrounding brickwork, and the furnace beneath,
which was some distance away from the bottom of the chimney-shaft, an
easier path of escape than the lightning rod. The Messrs. Gray advocate
the surrounding of the top of tall chimneys with a complete edging of
copper bands to obviate the possibility of accidents of this character.

A well-arranged multiple point reared well above the chimney, and
protected from the corrosive action of sulphurous fumes, would, no doubt,
answer quite as well. In the case of large and costly structures both
plans may, nevertheless, be advantageously combined.

Rain-water pipes, which are indispensable contrivances in all houses, may
be easily turned to account as lightning conductors ; but they must then be
made metallically continuous from some prominent point or points above
to an efficient earth-contact. All joints in the pipe must be absolutely

368 CONSTRUCTION OF LIGHTNING CONDUCTORS.

neutralised by well attached strips of metal carried over them from length
to length ; and o?er and above this, care must be taken that they are not
within striking distance of any superior line of conduction at lower parts
of the house, as, for instance, gas pipes connected with the main service.
If they are within such striking distance, there will always be a probability
that a discharge may leap across from them to the secondary line of con-
duction, and do mischief of some kind by the way. The Messrs. Gray
hare had one case within their experience, in which a discharge of light-
ning leapt in this way from a rain water pipe to an iron gas pipe, and
made a breach of continuity in the latter, and set light to the gas.

It is very much to be desired that protection from lightning should
enter as essentially into the designs of architects who plan houses ss
protection from rain. Sir William Snow Harris holds the honorable
position of having established that doctrine in regard to ships, and of
having perfected a plan for their protection from lightning that leaves
scarcely anything to be desired. Damage from lightning to vessels of the
Royal Navy is now virtually an occurrence that is never heard of. The
day, in all probability, will come when the same remark will be able to
be made in reference to houses, at least where these are gathered closely
together into towns. It is, indeed, quite possible that towns may be
made to bristle with pointed lightning conductors, until no charged
thunder cloud could retain a high tension charge when within. striking
distance, so that the flash of disruptive lightning would be virtually
banished from the urban precincts. This is really what has pretty well
happened in the case of the Capital of Colony of Natal, where lightning
rods of good construction have been rapidly multiplying in recent years.
Damage from lightning is now scarcely ever heard of within the town, al-
though the lightning is seen flashing immediately around with the most
vivid intensity every second or third day through the six months of the
hot and wet season.

Until lightning conductors are supplied with the rain water pipes to
houses as part of the architect's design, all intelligent men should know
just enough of leading principles of electrical science to be able to make
such arrangements for themselves, for the efficient protection of their
houses from lightning, as have been briefly glanced at in this paper. The
indispensable conditions that have to be secured in accomplishing this are
simply :—

CONSTRUCTION OF LIGHTNING CONDUCTORS. 369

1. The lightning conductor must be made of good conducting material
metsllically continuous from summit to base, and of a dimension that is
srtficient for the ready and free conveyance of the largest discharge that
can possibly have to pass through it. 2. It must have ample earth-con-
tacts, and these contacts must be examined frequently to prove that they
are not getting gradually impaired through the operation of chemical and
electrical erosion. 3. It must terminate above in well formed and
well arranged points, which are fixed and distributed with some definite
regard to the size, form, and plan of the building. 4. There must be
no part of the building, whether it be of metal or of less readily conduct-
ing material, which comes near to the limiting surface of a conical space,
having the highest point of the conductor for its apex, and having a base
twice as wide as the lightning conductor is high, without having a point
projected out some little distance beyond, and made part of the general
conducting line of the lightning rod by a communication with it beneath.
5. There must be no mass of conducting metal, and above all things,
no gas pipe connected with the main, within striking distance of the
lightning rod, lest at any time either the points or the earth-contacts
shall have been so far deranged or impaired as to leave it possible for dis-
charges of high tension, instead of continuous Btreams of low tension, to
pass through the rod, and to be diverted from it into such undesigned
routes of escape.

Discussion.

Mr. Pastorelli, in alluding to the importance of the paper, remarked
that he believed the public were very ill informed on the subject of light-
ning and conductors. With respect to the forest of metal chimney-pots in
towns, they enjoy comparative immunity ; this he attributed to the proxi-
mity of church steeples and other high buildings provided with lightning
conductors, for at their points the electric fluid would have a great tension,
and tend to flow towards the storm cloud, forming, as it were, a channel
for the passage of the electric fluid from the cloud to their points. If zino
pots were placed on an isolated house in a large open space, they should
be connected with a lightning conductor, otherwise they would prove
most dangerous.

Mr. Strachan said it appeared to him that the rules for constructing
lightning conductors were framed very much upon guess work, and he
supposed this must be so ; but there was a tendency to idealise too much.

370 CONSTRUCTION OF LIGHTNING CONDUCTORS.

The practice of the Engineers who did this kind of work was not uniform ;
much of it depended upon individual opinion, often crotchety, and seldom
admitting any proof of efficacy. Was it demonstrated that the resistance
of the conductor increased with its length ? Was there any certainty of
the utility of a couronne of points ? Beyond the simple facts that the
conductor should be pointed, continuous, and led into moist earth or water,
Tery little seemed known for certain as to the best construction of light-
ning rods. There was a tendency to make them complicated, notwithstand-
ing that the lightning rod in its simplest form as hitherto used had been
evidently useful, especially for ships. It is very seldom now a day that
ships were struck by lightning, and we infer that this is because their
masts are iron or fitted with conductors. The last instance known to him
was that of Her Majesty's Ship Shannon in or about 1857, which lost
topmast, although it was fitted with Harris* conductor, but suffered no
other injury, from a terrific lightning flash.

Mr. T. G. Smith, in reply to the Chairman, who asked whether he
could add anything to the brief account that had been given by Dr. Mann
of his notable experiences on the Linguard, said that the occurrence which
had been alluded to was certainly a startling incident. He did not think
he was altogether a coward, but certainly the first impression made upon
him when he realised the position his party was one of some alarm.
There was, however, no ready means of escape from the position. They
were wrapped round with the electrically charged cloud, and as the dis-
charge continued so gently, familiarity with the situation soon bred a sort
of contempt. They first stretched their alpen-stocks out to experiment
with the wooden staffs upwards, and they then distinctly felt the electrical
thrill passing through their bodies, and heard the crepitating currents
rustling into the staves ; thereupon they turned the iron points upwards
and the crackling sound was immediately increased, and the thrilling
sensations became much more powerful, they then experienced the sensa-
tion very strongly both in the temples and at the fingers-ends. Hie
direction plate was of brass, and marked with lines to indicate the points
of the compass and the direction of certain prominent objects in the stir-
rounding country, and was mounted upon stone ; it was covered by a large
iron hood some two feet or so across ; there was no electrical discharge of
any kind upon it. He had no doubt whatever that the points of the flag-
staff and of the alpen-stocks had really served as efficient safeguards to

CONSTRUCTION OP LIGHTNING CONDUCTORS. 871

his party, lessening the tension of the electrical charge which was imme-
diately around them : there must have been an enormous discharge during
the time they remained upon the summit, for it was continued unceasingly
for three-quarters of an hour.

Mr. D. Pidgeon said he spent last winter with his family in a house
built upon the cliffs which form the promontory of Rounham Head, in the
Parish of Paignton, about three miles from Torquay. It is a bold head
occupying a central position in Torbay, and juts well out to sea, the house
occupying a very exposed position, with the sea a near neighbour on three
of its sides. From the grounds, a door upon the cliff gives private access
to the shore by means of steps roughly hewn out of the sandstone rock,
and these formed a favorite position for watching the beauties of the bay
both in calm and stormy weather. Hard by the door stood a flag-staff
originally put up for the use of the coast guard, but now forming part of
the property. It consisted of a single mast, 50 feet high, very strongly
made, and substantially erected, having a metal vane at the top, and
stayed about 25 feet from the ground in the usual way, with galvanized
iron wire guy ropes. About a foot above ground the wire ropes terminate
in half-inch cable chains, which are carried some way into ground to an
anchorage. These chains are much corroded ; the metal in some of the
links being reduced to about one-eighth of an inch diamater, while ^others
remain of about their original size. The soil in which the chains find an
anchorage is red sandstone conglomerate, which from its position is per-
fectly drained and very dry.

February 25th was a day of incessant rain from early morning till mid-
day, with a cold wind blowing strongly from south-east. Soon after
noon the clouds broke, and the afternoon was made very beautiful by a
aeries of brilliant and changing atmospheric effects. Wind-galls were
frequent, and the sky now bright, but streaked with " mare's tails," now
dark with a passing scud. At no time during the day had there been
any sign of thunder. About 5 p. m., tempted by the beauty of the bay,
\\h wife, his son, and himself were on the shore, when a scud came up
with the wind and approached them rapiily; they watched its course over
the bay from Berry Head, and when it neared, fearing a wetting, they
made their way homewards by the rock stairs. The first drops of the
shower fell as they reached the flag-staff; and proving to be hail, they
halted, standing in partial shelter grouped around the staff, while waiting

VOL. V. SECOND 8KRIKS. 3 D

372 CONSTRUCTION OP LIGHTNING CONDUCTORS.

for the scad to pass. His wife and son occupied the doorway, the former
looking over the door oat seaward, the latter close to her, and both a dis-
tance of 10 feet from one of the mooring chains. He stood some 20
feet from them, and 10 feet from another mooring chain. While in this
position, a flash of lightning struck the flag-staff, breaking the mast

short off immediately below the metal vane as well as at a point 11 feet

lower, rending into shivers all the wood between the vane and the point
of attachment of the wire gays, and scattering the splinters in every
direction, while the wreck of vane and mast fell within a few feet of their
party.

On examination it was found that the broken staff was blackened round
half its diameter ; the edges of this discoloration forming ragged splashes;
the brass tube of the vane was ripped open for fonr inches along the
joint at top and bottom; and all solder about the vane was melted.
Three of the mooring chains were broken ; the links being snapped short
across in many places, and some of the links fractured in more than one
place. The broken surfaces were bright and crystalline, showed no signs
of heat, and no diminution of sectional area at the points of fracture.
About 20 links altogether were broken, some above and some below
ground ; many of those which had suffered most from rust were snapped,
not across the reduced, but across the fall section iron. It is worth
noting that one of the rusty chains had given way in a gale some time
before this occurrence, and that his son had mended it temporarily with
an S hook made of galvanized wire not more than one- tenth of an inch
diameter. In this chain several links were broken through their full
uncorroded diameters, while the slight wire S hook remained intact.
Fragments of the shivered wood were found 150 feet to windward, measur-
ed distance ; those flying to leeward would fall into the sea. The flag-staff
formed the centre of a wide circle of gravelled path, from which other
gravelled paths led to various parts of the garden. At the point where
each mooring chain entered the gravel, a notable pit-like depression was
formed, and a walking stick could be easily thrust into the ground for
nearly a foot in each pit. On one of the paths radiating from the staff,
and about 20 feet distant from it, stood an iron garden roller. A shallow
trench in the gravel forking into two sinuous scores radiated from the
mast towards this roller. The shorter of these, eight feet long by fonr
inches wide and three-quarters of an inch deep, terminated in a splash

CONSTRUCTION OF LIGHTNING CONDUCTORS. 373

of gravel on the periphery of the roller at its point of contact with the
ground. The longer score left the roller on one side, and was lost in
the gravel some four feet beyond it. Two other similar but small scores
were traced about an iron drain grating in the same path, and a score six
feet long ran along the gravel path to the spot where he stood. All
these scores or trenches were roughly radial to the staff.

Very heavy hail followed the flash, and the sky became exceedingly
threatening ; the wind fell instantly on the discharge to a dead calm.
Twenty minutes later a second but distant flash was seen, after which
there was no more lightning.

To observers placed anywhere within three miles of the spot, the light-
ning appeared as of very exceptional intensity. The coast Guard Officer,
distant some quarter of a mile, compares the explosion to that of a 300-
ponnder gun. His servants in the house, distant 150 yards, u never saw
such a flash,'1 and a scientific friend at Torquay described both flash and
crash as " terrific.19

In describing the effects upon themselves, he felt so strongly the danger
of including subjective matter, that he would confine himself strictly to
repeating the statements which they made to one another respecting their
sensations immediately after the occurrence, and before their minds had
time either to forget or add, in any degree, by reflection to the facts.

Of the three, his wife alone was felled to the ground, his son and him-
self remaining erect, and all three retaining consciousness. When the
flash occurred, his wife was looking seaward over the door as mentioned
above, but they found her lying on her back upon the ground in precisely
the opposite direction, her face being turned away from the bay. None
of them have any certainty of seeing a flash, and his wife is quite sure she
saw nothing. Similarly, none of them heard the terrific explosion accom-
panying the discharge, but his wife was conscious of a " squish,1' recalling
squibs to her mind ; his son of a loud " bellow,11 while he seemed con-
scious of a sharp " spang," with little hold on its objective reality. His
wife describes her general sensation as that of " dying away gently into
darkness," with a distinctly subsequent feeling of being roused by a tre-
mendous blow on the body. On raising her from the ground she com-
plained of great pain in the legs, which refused to carry her, and they had to
support her into the house. The lower limbs remained paralysed for some
time, giving at the same time great and alarming pain ; but this passed

374 CONSTRUCTION OF LIGHTNING CONDUCTORS.

off in less than an hoar. On undressing her, a distinct smell of singeing
was noticed, and she was covered from the feet to the knees with tree-like
marks branching upwards of a rose red colour, while another large tree-
like mark, having six principal branches radiating from a common centre,
and 13 inches in its largest diameter, covered the body. It is worthy of
remark that the centre of this figure coincided exactly in height from the
ground with the iron bolt of the door against which his wife was leaning,
and it also marks the spot where she was conscious of having received a
violent blow.

His son affirms that he received a violent shock in both legs, and that
it was electrical in character, while he was conscious only of a sadden and
terrific general disturbance affecting chiefly his left arm and throat, bat
with nothing electrical about it. It is certain that some appreciable time
elapsed before any of them referred the occurrence to its true cause. His
wife remained under the impression that they had been fired upon, and
that she was wounded, until he told her that the mast had been struck by
lightning. His son and himself had both a momentary feeling of intense
anger against some " persons unknown " for what they thought was a
trick. He did not think he recognised lightning till after his first glimpse
of the wreck lying on the ground around them. His wife is the only
one of the three who had any sensation of smell, and she is quite clear on
the point. The lighting of a match was sufficient to bring the occurrence
back vividly to her mind for a long time afterwards. For a very few
moments, both his son and himself failed to articulate, their months moved
in an attempt to speak, but the first few words on both sides were quite
unintelligible. That there was an unconsciousness to surrounding objects
of some seconds' duration is clearly shown by the fact that none of them
saw or heard the heavy mast fall to the ground, though, descending
through 50 feet, it must have taken at least two seconds to reach the
earth. A correct drawing of the chief lightning impression on the skin
described above, was carefully made from measurements taken at the time.
The branches were about a quarter of an inch in width, bright rose red,
and were all faded away in four to five days. The skin, where reddened,
was sore to the touch like a scald or burn.

Dr. Tripe said he did not propose discussing Dr. Mann's paper, hot
desired to make some remarks about ball lightning. On the 11th of July
of last year he was watching the progress of the most fearful storm he

CONSTRUCTION OF LIGHTNING CONDUCTORS. 875

ever witnessed, of hail, rain, wind, and lightning, and was looking due
south, where he saw a large ball of fire rise apparently about a mile dis-
tant from behind some low houses. This house is situated on the borders
of the London fields, which are, in that part, about a third of a mile across ,
so that he had an uninterrupted view of the phenomena. The ball, which
appeared about the size of a large cricket ball, at first rose slowly, but
accelerated its pace as it ascended, so as gradually to acquire a very rapid
motion. When it had risen about 45°, it started off at an acute angle
towards the west, with such great rapidity as to produce the appearance of
a flash of forked lightning. It made three zig-zags before it entered the
dark cloud, from which flashes of sheet lightning were coming. About
10 minutes afterwards he saw a similar ball, which, however, rose more to
the west, in the direction which the electrical cloud was taking, when a
similar occurrence took place ; the ball rising to about the same elevation
before starting off as a flash of forked lightning. These balls seem to be
dissimilar to those which descend, as the pace is greater at the latter part
of its course, and the colour lighter. The colour of the ascending ball
lightning which he had seen was light yellow, whilst that of the descend-
ing ball was bluish.

Dr. C. J. B. Williams remarked, in reference to Mr. Pidgeon's descrip-
tion of his stroke by lightning, that he neither saw the flash nor heard
the sound, that such was the common experience of those struck by light-
ning, they were so stunned by the shock to the nervous system, that all
sensation was suspended for the moment : when they recovered conscious-
ness they could not speak for a time, because the muscles concerned in
speech were benumbed from the same cause. With respect to the ball of
fire, moving deliberately, and then passing into a flash of lightning, he
must doubt the identity of the phenomena. After such evidence, he would
not question the reality of the ball of fire as an electric meteor; but its slow
motion and course must distinguish it from the lightning flash, which darts
from east to west, from one horizon to its opposite in an inappreciable
instant of time. To find its analogue in experimental electricity, we must
seek for the representation of the ball of fire in the brush or star, or some
such slow coruscation of electric light, and not in the vivid and instan-
taneous spark from the battery discharge, which truly represents lightning.
To turn to a more practical part of the subject, he wished to call attention
to the remarkable liability of some districts to thunderstorms, and their

376 CONSTRUCTION OF LIGHTNING CONDUCTORS.

great need of efficient protection. Two years ago he visited Gais, t high
village of Appenzel in Switzerland, famous as a resort for the milk cure.
He was surprised to see that every house had its lightning rods, in num-
ber varying from two to eight, according to the size and complexity of the
building. On inquiry, he found that the place was subject to the visi-
tation of thunder-storms so terrific and frequent, as to keep the inhabitants
in continual dread ; and in spite of the protection of the conductors, con-
flagrations were very common. A storm, which raged for 10 hours, had
occurred in the previous week : telegraph posts were shattered to splinters,
and two chalets were burned to the ground, although each of them hid
two rods. He had met with nothing like it in other parts of Switzerland,
however high and exposed. He thought this extraordinary proclivity to
thunder-storms must be due to the fact that this district forms the first
high land after the wide expanse of the Lake Constance, and the rut
plains of Wurtemberg and Bavaria, which are comparatively low. Al-
though rising little more than 3,000 feet in height, it formed the foremost
spur of the Sentis Range, and would attract the clouds charged with
negative electricity, which gathered from the plains below. Sach was a
place to test the efficiency of the protecting rods, and nothing was more
likely to cause failure than want of moist conduction to the earth ander
the houses with projecting roofs, and where the underlying rock is dry
limestone and conglomerate.

A preceding speaker had alluded to the danger in towns from the
many zinc and iron chimney-tops without sufficient conducting connection
with the earth, but he believed this danger to be confined chiefly to isola-
ted buildings, or scattered villages, where the chimney-cans are few. la
large towns there is such a forest of metallic tubes, more or less angular
or pointed, that even with imperfect conducting power, they most draw off
quietly a great deal of electricity, and render towns more safe than country.
He would apply the same remark to large trees, which, although not per-
fect conductors, are moist enough to draw, off a vast deal of electricity
from the clouds. In his youth he resided opposite some of the highest
trees of a large park, and he had often noticed during a thunder-storm a
little column of smoke above some of the topmost boughs. After a few
months these boughs were dead, doubtless gradually killed by the heating
effect of the electricity in passing through their imperfectly conducting
material. Often since, in Hyde Park and elsewhere, he had noticed that

CONSTRUCTION OP LIGHTNING CONDUCTORS. 877

the topmost boughs of the highest trees were dead, he bettered from the
same cause. Although heated and injured bj its transit (like a fine plati-
num wire by a battery) trees gave proof that they do draw off electricity
from the clouds, especially when wet, and thus diminish the danger to the
adjoining country.

Mr. Scott said that there could be no doubt as to the occasional occur-
rence of globular lightning, which moved very slowly ; the evidence of this
was too strong to be controverted. With reference to the possibility men-
tioned by Dr. Williams of the tops of trees being killed by constant electric
discharges passing through them, he would like to ask whether this was
not more commonly attributable to the fact of excessive drainage, as in
Kensington Gardens, having affected the health of the tree. He finally
drew attention to the constant error of stating that the lightning rod drew
the electricity out of the cloud, whereas it more correctly might be said to
allow the electricity to escape from the earth.

Mr. Birt said that on the occasion of the storm alluded to by Dr. Tripe
two elms situated near Ley ton Green, about a quarter of a mile from his
residence, were struck by lightning. The upper branches of one were
completely withered, but otherwise the tree was uninjured. The path of
the lightning is not only traceable, but distinctly visible, along the trunk
of the other now standing ; a portion of the bark between 15 and 20 feet
above the earth's surface of about six inches wide having been torn away.
It was at this point that the lightning appeared to have left the tree ;
for below it the trunk is apparently sound, the lower branch lets having
produced healthy shoots this spring. There were several trees in his im-
mediate neighbourhood that have lost their upper branches, and he was

•

disposed to regard lightning as the agent which had killed them.

Mr. Whipple asked if Dr. Mann would state what was the electrical
conductivity of bricks when wet. He thought that a house covered with
a metal roofing would be as safe as if bristling with points. With refer-
ence to what had been said about locality, he would mention that some
time ago a tree was struck by lightning in Richmond Park, and on going
to see it, he found that it was on a spur of a hill stretching out from
Richmond Hill. He believed that ball lightning was a reality; for a
friend of his had described to him the track of a ball in his garden which
went off in the same way as mentioned by Dr. Tripe.

Mr. Field asked whether the pipes for the ventilation of drains might

378 CONSTRUCTION OF LIGHTNING CONDUCTORS.

not be dangerous as attracting lightning, unless properly connected with
the earth ; and whether by proper connection they could not be made good
lightning conductors.

Dr. Mann said, in reply to various remarks that had been made, and
in allusion to some matters that had been suggested during the discus-
sion, that these had been of so interesting a nature that he could only
regret there was not larger opportunity to dwell upon them adequately,
because there were so many topics to deal with. In reference to the case
of the metal chimney-pots in great towns, he quite believed they might,
when very numerous and closely planted, conduce to 6ilent and gradual
discharge, and that this was one reason why accidents from them were not
more frequent. Large masses of bad conducting material, metal-tipped
with sharpish edges in this way, would carry off as much electrical dis-
charge as small rods of good conducting capacity, and this would more
especially happen where there were soot-blackened chimneys leading
quite down from them to near the earth. In reality there was no absolute
distinction between conductors and non-conductors in electrical science,
it was merely a case of degree. Everything conducted in some degree,
but more or less, according to its nature. In regard to resistance being
increased in proportion to the length of the conductor, as well as to its
smallness, that was thoroughly well known to electricians, and he had al-
ready given the expression for the fact, as it had been ascertained by
direct experiments, in scientific form in the paper. Mr. Cobb had cor-
rectly accounted for the accident to the Shannon, but he thought he might
also add that the old practice in regard to ships was to care more abont
massive terminations than points. He still found remnants of this tra-
dition in the practice of Mr. Gray, who was the skilful successor of Sir
W. Snow Harris in this particular branch of work. Wherever unpointed
terminals were used, there would always be much greater mechanical
effect produced at the termination of a conductor than within its main
line. This was an additional reason for the adoption of points. He
could not admit that there was resistance of any kind set up by points, the
operation was entirely the other way ; resistance was diminished the in-
stant a pointed form was given to the termination of a conductor. Bat be
must add that he doubted whether Mr. Lecky really meant " resistance "
when he used the word. He simply, he believed, wished to bring promi-
nently out the fact, that when points were employed, there was a double

CONSTRUCTION OF LIGHTNING CONDUCTORS. 379

action set up by them — an influence in a double direction, a stream of
electrical force was poured out from the earth through the point to the
air or cloud, and another stream was simultaneously drawn from the cloud
to the earth. In this Mr. Lecky was unquestionably right. The well-
known experiment with the discharge of a Leyden jar through a card
points to a double passage even more strikingly than Mr. Lecky'e double
trial left upon the glass from a discharge by overflow. Points of metal
connected one with the inner, and the other with the outer, coating of the
Leyden jar, are placed touching opposite surfaces of a card, and when the
discharge is passed through the card, both surfaces are found raised out-
wards ; there is a convex burr in both directions. This is generally accept-
ed by electricians as indicating that the opposed forces cross each other
in opposite directions whenever there is an electrical discharge. The term
" ascending " and " descending lightning " can only be tolerated by exact
Ecience, if taken in the limitation of expressing the direction in which the
mechanical or material effects of the discharge are propagated. M. Gal-
land, in reference to this very question of the cross passage of the double
discharge, says — " The lightning does not fall. The two electrified bodies
produce between them an exohange of fluids, when the electrical tension
of these fluids is sufficiently intense to conquer the resistance of the insu-
lating substance which separates them." " Le ruban de feu qui unit le
nuage a la terre va aussi de la terre au nuage." The transport of pond-
erable matter can only be looked upon as an indirect and secondary
mechanical effect of the discharge, and can never be taken as indicating
the direction of the movement of the discharge itself. Mr. Smith was
assuredly within reason in his inference as to the .large amount of the
electrical discharge through the flag- staff and alpen-stocks on the Lin-
guard. Arago estimated the amount discharged by a system of points
placed upon a palace by Beccaria under somewhat similar conditions, as
being enough to kill 3,000 men in the hour. In considering the interest-
ing instance supplied by Mr. Smith, however, it must not be overlooked
that the flat direction plate and iron hood were mounted upon stone,
which is a much worse non-conductor than wood, such as formed the staffs
of the flag and of the alpen-stocks. Dr. Williams1 view as to the physio*
logical influence of the Torquay discharge upon Mr. Pidgeon, and his
companions, is unquestionably philosophic and correct. When Professor
Tyndall accidently received the shock of the large Leyden battery of the

VOL. V.— 8ECOND SERIES. 3 B

380 CONSTRUCTION OF LIGHTNING CONDUCTOR*.

Royal Institution through him, he was quite unconscious of haying been
struck by it, and felt absolutely nothing. Mr. Pidgeon's case was, in all
probability, a strictly analogous one. He states that he was quite unable
to say absolutely whether he felt any shock. He was puzzled and con-
fused, and seems most inclined to think he was not struck, because he
could not distinctly bear testimony to the shock. His state of brief
inability to feel and move, however, sufficiently manifests that some dis-
charge did pass through him. In the case of Mrs. Pidgeon, the mark
of the discharge was left stamped upon the skin. In Mr. Pidgeon's in-
stance the full lightning discharge obviously did not pass through him
and his companions. Either they were under the influence of a secondary
return shock at the instant of the discharge of the lightning, or the dis-
charge passed from the chains at the bottom of the metallic 6tays of the
flag-staff expansively and centrifugally to a very large area of the imper-
fectly conducting ground, affecting everything in a comparatively slight
degree through a very large space, the living bodies chancing to be placed
there amongst the rest. In a somewhat similar case, recorded, if his
memory did not deceive him, by Mr. Walker, the lightning was once seen
to make its escape through a dry earth -contact of a lightning rod of a honse
in Philadelphia, as a broad sheet of fire several yards in extent The ball
lightning is a well known and carefully observed phenomenon, and is in
every case diagnosed and distinguished from ordinary lightning by its
very slow progress, allowing, indeed, ample time for its movement to be
leisurely observed. But the " fire-balls " Mr. Pidgeon speaks of were
manifestly not of this character, they were seen by persons " standing
with their backs to tjie discharge." They were simply the glare of Hie
instantaneous light filling for an instant the space immediately around the
spot most immediately affected by the final communication with the earth.
The disruption of the chains is one of the interesting incidents of
Mr. Pidgeon's case. Mr. Pidgeon states that not less than 20 links were
broken across. This was due certainly to molecular disturbance mecha-
nically produced in the substance of the chain at the instant of the dis-
charge, and possibly taking effect most violently at parts of the metal
which were already in a 6tate of flaw, or approximate disruption. The
power of lightning to contract materially the length of metallic masses
when it passes through them has been observed in various instances. Mr.
Walker has placed upon record one case in which a wire was so shortened

■

CONSTRUCTION OF LIGHTNING OONDUOTOB8. 881

in a house in Stoke Newington by the passage of a discharge of light-
ning through it, that a night bolt, with which it was connected, could no
longer be thrust into the fastening which previously received it Some
action of this kind possibly contributed to the fracture of the chain links
at Torquay. The destruction of the vitality of the upper branches of
trees by electrical action, spoken of by Dr. Williams, is a well-known
effect. Mr. Viollet-le-Duc describes a space of 500 metres square, in the
forest of Compiegne, in which all the upper branches of large trees have
been stripped of foliage by electrical agency, although the lower branches
of the same trees are untouched. The cups of an anemometer, such as
are spoken of by Mr. Field, are of 6uch small dimensions, that they
could hardly be considered in themselves as causing any material increase
of danger. But the correct principle, of course, is that such objects should
be dominated by a lightning conductor. The stripping of the gilding
from the column beneath the chain cable affected by the lightning dis-
charge brought under notice, was moBt probably due to inductive influence,
and to a secondary lateral discharge. It has already been suggested by
Mr. Preece that pipes used to ventilate the sewers might be converted in-
to lightning conductors. To use them for that purpose, it would only be
necessary to see that they were of sufficient dimensions, and to furnish
them with good terminal points, and with good earth communications.

[A larger copper tape than the one previously described, two forms of
copper multiple conductors, and a plan for securing metallic conductors
against the influence of corrosive fumes by tubes of ebonite, were exhibit-
ed at the close of the Meeting by Messrs. Sanderson and Proctor].

Dr. Mann finally drew attention to various subordinate matters that,
in connection with this subject, especially require more extended investi-
gation, and he especially referred to the dimensions of conductors ; the
effects of the practice of coating good conducting substance with metals
of inferior power; earth-contacts in general, and especially the compe-
tency of the ordinary telegraphic methods for testing maintenance of
efficiency in them ; the phenomena of return shocks, and of lateral and
divergent strokes ; the area of absolute protection ; the systematised con-
nection of metallic masses ; the cause of the disruption of chain links ;
protection of lightning conductors from corrosive fumes ; the protection
of chimney shafts ; the molecular change effected in copper by time ; the
height and distribution of the upper terminal of lightning rods ; and the

382 CONSTRUCTION OF LIGHTNING CONDUCTORS.

best construction of points. He also stated that it was under the con-
sideration of the Council of the Society to determine whether a permanent
Lightning-rod Committee for the farther investigation of such matters
might not be advantageously formed. If such a Committee were consti-
tuted, its immediate functions would probably be threefold — 1st, to collect
and record facts relating to accident and injury from lightning; 2nd, to
investigate certain moot points of scientific principle and construction, such
as those which had been specified ; and 3rd, to report and publish the
progress of its labours in both directions from time to time.

Committee of the British Association for the Advancement of Acmes— re-
appointed at the Meeting at Bradford to investigate the efficacy of lightning-
conductors, to give suggestions for their improvement, and to report upon
any case in which a building professedly protected by a lightning con-
ductor has been injured by lightning — consisting of Jambs Glaibhkr,
Esq., F.R.S.; Lieutenant-Colonel A. Strange, F.R.S.; Profmor
Sir William Thomabon, P.R.S. ; Charles Brooke, Esq., F>R S.;
Charles Y. Walker, Esq., F.R.S.; M. DeFonvibllb, of Paris;
Professor Zbnger, of Prague ; and Dr. Mann, (Secretary).
• # * *

The Committee charged with this investigation and report, desires to
have as much information as possible regarding accidents from lightning.
But in order that information of this class may possess scientific rake,
it is essential that all statements communicated should be clearly and de-
finitely expressed, that they should be carefully authenticated, and that
the address, as well as the name, of the observer should be given, to allow
any further inquiry to be instituted that may be found to be desirable
in the circumstances. The Committee has consequently drawn up the
following memorandum to define the nature of the information it seeks,
and earnestly requests that any person who may chance to know of ac-
cidents from lightning, or who may be able to give practical assistance in
this inquiry, in the sense and particulars suggested by the memorandum,
will address such communications as they may be in a position to make
on these subjects, to the Chairman of the Permanent Committee on At-
mospheric Electricity and Lightning-rods, Meteorological Society, 30,
Great George Street, Westminster, London.

CONSTRUCTION OF LIGHTNING CONDUCTORS. 383

Memorandum of information required in any case of accident from lightning.

1. The day, hour, and place of the occurrence.

2. The exact nature of the occurrence, especially specifying any un-
usual appearance or sound that has attended the discharge of lightning.

3. A minute and precise description of any damage that may have
been produced by the discbarge.

4. Record of any visible traces of electrical action that may have been
left in the track of the discharge.

5. The names and addresses of any persons who may have witnessed
the actual discharge producing damage, or who may have suffered in any
way from its effects.

6. The existence or non-existence of a lightning rod in any form in
the immediate neighbourhood of the accidents, and an exact description
of the rod when any such appendage has been ascertained to be near, es-
pecially as to—

(a) the nature of the metal of which the rod is composed :

(b) the size of the rod :

cylinder, of a tube, of a flat strip, of a chain, or of a wire-rope :

(d) the actual continuity of the conductor from end to end :

(e) the character of the termination above, and the distance to which

it extends there beyond any building or solid structure :
(/) the character of the termination below ; whether in dry or
moist ground, how it runs into the ground, and how the
earth-contact is ultimately made :
(g) the manner in which the conductor is connected with any build-
ing, and especially whether there are any masses of metal
in the building near, and whether such masses are or are
not placed in metallic communication with the conductor.

7. Allusion to the fact whether the injurious discharge did or did not
form part of an ordinary thunder-storm in progress at the time.

8. In case of the occurrence of a thunder-storm in progress at the
time of the discharge, a description of the character of the storm as to
intensity, duration, fall of rain, and apparent movement over the locality.

9. Any subsidiary or incidental observations that may have been made,
and that may seem to bear practically upon the physical conditions and
circumstances of the phenomenon.

R, J. M.

384 IMPROVED FORM OP THERMANTIDOTE.

No. CCVII.

IMPROVED FORM OP THERM ANTIDOTE.

[ Vide Plate XLIX.]

By H. Bull, Esq., Asst. Engineer, Military Works, Agra.

It is a matter of much surprise that whilst a good thermantidote
is, daring the hot weather, a very great want, if not an absolute necessity,
one meets with so few whose action is really satisfactory. Most are so
constructed, that when one puts one's neck actually in the outlet channel,
a refreshing and perhaps strong breeze is felt, bat a few feet off the
effect seems entirely lost The drawings accompanying this Article are
of a thermantidote, the details of which having been first worked ont
theoretically, were found in practice to be thoroughly effective, and are
sent for publication, in the hope that they may be of use, not only to the
Engineering profession, but to the general public. The construction
is extremely simple— the lower half of the air chamber is of brickwork,
the side walls only being of necessity set in lime, the inside faces being
all pucka plastered. The upper half is removable at will, being con-
structed of one inch planking at the sides, and the curved part of thin
iron sheeting, stiffened by cross pieces, to which, and also to the sides, the
sheeting is nailed or screwed. In the fans there are no complicated
joints as in an ordinary thermantidote; each arm, or rather each pair of
arms, is cut out of a one inch plank to the requisite shape, the three double
arms are then set into the required position, the £-inch clamping plates
set on either side in the middle, and the whole screwed up with 3-inch
bolts, care having been taken to fill in between the planks and between
the planks and plates, with stiff glue, and also that the hole for reoeiv-

4>f*

c
<
I
<
<

1MPR0VRD FORM 'OF TIIKRMANTIPOTE.

385

ing the spindle has been properly cut. The supports of the bearings
may be of stone or wood, the former in preference. The only parts re-
quiring skilled labor are the bearings and spindle ; these should be truly
turned, so that there may be as little friction as possible, the former
being of brass. The cost of the spindle and bearings should not be more
than Rs. 25, the remainder of the work costing about Rs. 125, making
a total of Rs. 150.

The cover is shown much wider than it need be, one inch clear play for
the fans (the same as in the lower part of chamber) being ample, the side
planks are one inch thick, stiffened by pieces 1 ^-inches thick. Blocks of
wood are placed directly under the bearings, and also as a sort of washer
under the stone, to act as cushions and prevent jar. The brickwork
might also be carried up two or three layers higher than is shown, this
would keep the supports of bearings much more firmly, and lessen the cost
of the iron, the expensive part. It need hardly be pointed out that the
passage from the thermantidote has to be suited to the form of building
in each case. In the case shown, there is doubtless some loss of velocity,
but this could not be helped, the height of passage being fixed by the
levels of the verandah and main building. Were the plinth very high

Fig. 1.

Fig. 2.

indeed, the fans should be turned over
so as to work in the opposite direction
as in Fig. 1 ; the cover in this case
would be partly curved, partly straight.
If the plinth be very low, the form
would be very similar to the drawing,
the only exception being that the outlet
instead of being curved upwards would
turn out straight as in Fig. 2.

The work in first thermantidote was
carried out from rough sketches, and
though there are defects, some of which
are pointed out above, it worked very
well, as the following results will show.
I have therefore shown it as actually constructed.

It was working at one end of a ward 82 feet long, 24 feet wide and
H feet high, so there was ample room for the stream to disperse, it
nevertheless blew out a candle at a distance of 60 feet from the month ;

886 IMPROVED FORM OP THRRM ANTIDOTE.

it put the whole of the heavy English counterpanes in motion, which
were on the beds distributed over the room; it blew a large sola
topee a distance of 25 feet; in fact it gave a breeze all over the room.
On trial it was found that the action was so easy, that it required
only the slightest pressure to put it in motion, and after working it hard
for a few seconds and letting go the handles, it continued revolving 17
times.

It may perhaps be noted that no arrangement is made for the khus-khua
tattie, this it is thought unnecessary ; in an ordinary thermantidote the
tattie is pressed close up to the air inlet. This it is believed, is a great
mistake as lessening the inlet area ; were this area lessened from a aide
four feet in diameter, as in the accompanying Plate XLIX., to one a foot
in diameter, the mistake would be at once apparent, and yet the common
custom above noted is just such a mistake, as the only inlet for the air
is between the fibres of the grass, lessening the required area to perhaps
an even greater proportional extent. What is recommended is to have
a cold air chamber on either side as capacious as possible. This can be
managed by having the tatties made in the form of a box without a top,
kept in place against the sides of the thermantidote by struts, and fitting
closely all round ; the face tattie should be as large as possible, 7 or 8 feet
square, and kept away from the thermantidote by the side tatties, as far
as possible, one foot being a practicable distance in this case. This would
give a total area of 70 or 88 square feet of grass for the air to be drawn
through. The spindle is made of such a length that there is ample room
on either side to fit a multiplying wheel, but this it is thought unneces-
sary ; with a rope fixed to the handle and the cooly simply pulling when
the handles comes into a vertical position, SO pulls a minute (a number
the laziest cooly would work to) would give a velocity to the outer edge of
the faces of over 9 feet a second. A large machine moving slowly is, it
is thought better, than a Bmall one at a high velocity, as it distributes the
stream of air better.

H.B.

Note.— The writer, who is at present Uring at Sahibgnnge, vfei Sickree Gnley, will hi hsppy
to answer any references.

PATENT COMBUSTIBLE DAMPER FOR BULl/8 KILNB. 387

No. CCVIIL

PATENT COMBUSTIBLE DAMPER FOR BULL'S KILNS.

[ Vide Plate L.]

Bull's Patent Kiln is now very generally known, as the numerous appli-
cations for licenses, and enquiries as to its working, testify ; and as once
taken up, it is generally adhered to, any improvements, either lessening
its cost, simplifying its working, or increasing its working powers, will it
is thought, be of general benefit. In the October 1875 number of the
Boorkee Professional Papers,* an Article was published on a modified
form of the kiln referred to, which has been adopted in several places
with success. Since that Article was written, an addition has been
thought of, which, whilst necessitating a much lower kiln, (a point how-
ever in its favor, as the loading is thereby rendered more easy, and the
cost of kilu is considerably lessened,) gives just as quick, though much
surer outturn, and lessens the consumption of fuel considerably. This is
a combustible damper, consisting of a sheet of the coarsest .cloth, with
the coarsest paper pasted on to it, to render it as air proof as possible.
It runs up through the middle of a flue as shown in longitudinal sec-
tion, and reaches to either side, against which it is kept by a brick in
every second or third layer being placed up to the walls. Between this and
the firing the chimney comes, and all openings between the damper and
the firing being closed, the chimney cannot possibly draw except from the
fire. The damper need not of necessity be as close to chimney as shown
in drawing, as long as all openings between it and firing are completely
closed, but loading being well ahead of firing (at least 25 flues), one
should be placed near each second chimney space, so that at each alter-
nate move of chimney (spaces for which are left at each fifth flue) the
damper will be five flues away from chimney ; when a greater distance off

• No. CLXXTV^ No. 18, Vol. IV., Professional Papers on Indian Engineering, Second Borta.
VOL. V.— 8KCOND BER1K8. 3 P

888 PATENT COMBUSTIBLE DAMPBB FOR BULL*8 KILK8.

than this, their action fails to a certain extent. Though the dampers
hare a good effect, with even the low brick chimney, it is slight as com-
pared with what they have with the high iron chimnies as described in
the former Article. Three of the size first described in that Article are
ample with the low kiln; a slight modification is recommended, that of
making the width at top 20 instead of 15 inches, the same iron being used
as before, this increases the area at the top slightly, rendering it more
nearly equal to that at the base.

Parties using the kiln of the original pattern, have found difficulty in
finishing and closing six or even five flues a day with eight fines being
fired, but the writer of this has with the greatest ease for an extended period,
been able to close seven flues a day, with two flues being fired fairly hard,
two very easily indeed, and two in doorways only, the average consumption
per lakh on 20 lakhs fired from the end of October, through the cold wea-
ther, to the end of March, being 8,057 cubic feet of wood, averaging five
inches in diameter, and 466 cubic feet of branches, averaging one inch in
diameter, or — allowing four cubio feet of former, and ten cubic feet of latter,
to the maund — 810 maunds. At times during the cold weather, it was found
impossible to get the loading done as fast as the firing. Before describ-
ing the new method of working, the principle will b« explained on which
the success in working depends. This has been arrived at, after prolonged
thinking, and after number of experiments, both on ideas of my superior
officers, and my own, as to utmost capacity of the kiln, both for burning
bricks as well as tiles, and of the best method of loading and firing them.
The supposition is started with that a considerable length of kiln has
been fired, for it is only just at starting that this is not the case. Say we
have a length of 100 feet fired and finished, we have then a large stock
of heat to help us, and the object is to draw this forward into the still
unfinished bricks in the most useful manner. Now whilst this back heat
is drawn nearly horizontally forwards by the powerful draught of the
chimneys assisted by the damper, it naturally tends to travel at as high
a level as possible. It can be readily understood that whilst this back
heat will raise the unfinished bricks, into which it is drawn, to a consider-
able temperature, it cannot raise them to quite its own temperature; it is
necessary therefore to get some help from the fuel for even the very top-
most brick. In the same way that the back heat is drawn horizontally
forward, the heat (and consequently the flame) from the fuel itself is drawn

PLATE L.

Wall of temporary chimney.

Across the kiln this is 1
brick wide,

■Patent Damper in elevation

'Binders of ft brinks run-
ning right across Kiln
to strengthen malls mid-
way between flues.

rich closing corbels,
+Corbelhng over brick*

Ground line.

>j>en space.

tdinally or transversely
ft between them.

ECTION

-'/

\ey \B ft wren concchtnr
walls.

Brtck left out till closing of Chimney,
when it is put in and space covered with
tiles or layer bricks specially made.

HWsl OAMPtt

Thin is mean width, for width
varies, being 15* at inner edge,
nd 17" at outer edge inside.

REFERENCES

Pieces of brze* keeping
damper down to floor.

Patent Damper in Elevation. I

Earth 1 — -

Kucha Brickwork — I

Bricks in Section

Corbelling over Brick*-- . -
Bricks in Elevation

PATENT COMBUSTIBLE DAMPER FOR BULL'S KtLHS. 889

and only a small proportion of them reaches the top bricks. There is no
difficulty whatever in getting the lower bricks well burnt, as they get by
far the greater effect of the intense heat of the fuel, in addition to a pro*
portion of the back heat travelling forwards. The object is to so arrange
the firing, that whilst the lower bricks are thoroughly heated by the
intense heat of the burning fuel, with a small proportion of the back
heat, the upper bricks are similarly heated by a large proportion of the
back heat, and a small proportion of the intense heat of the fuel. I use
the word intense purposely, as though the heat given away by the fully
burnt bricks is very great, that from the fuel is much greater. To reduce
this to practice — if after unloading, it be found that the lower bricks are
nnderbumt, fire harder, by either feeding more Juel into each flue, or by
firing more floes; if the upper bricks are nnderburnt, feed less fuel into
each flue, or fire fewer flues.

As a help to those who have had little or no practice in brick burning
with the Patent Kiln, rules will now be given for starting and carrying on
the operations, recapitulating to a certain extent what has been written
in the former Article.

Build a wall across the kiln 4 feet high, 2 or 1 J feet thick, and midway
between two flues, leaving four or five openings at base six inches square.
Load at least 20 flues, leaving a chimney space at the 15th flue, and after-
wards at every 5th flue. The time of covering in with earth is not of
much consequence, so it is recommended to cover up to the first chimney
before firing, set up chimneys at 15th flue, damper being just beyond,
and a damper at every 10th flue or second chimney space in advance, if
there be no fear of the firing proceeding faster than the loading, but if
there be, at every chimney space ; fire the first two flues— three hours
after, two more — three hours after, two more— leave all flues open till
they have well taken fire, then close with the earth dummies and plaster
round them with mud, opening them for firing only; never close
the openings in cross wall at all. Fire fairly hard Dos. 1 and 2 when
the bricks are well heated, but Nos. 3 and 4 very easily indeed, with the
exception noted below; Nos. 5 and 6 with the fuel not thrown into
kiln, but partly in doorway itself, and partly in kiln. In all flues, fire aa
hard as possible against sides of kiln, putting the largest and best pieces
with their length say three-quarters in kiln and one-quarter in doorway.
When the bricks in No. 1 flue are at a perfectly white heat, close the

890 PATENT COMBUSTIBLE DAMPER FOR BULL'b K1LHB.

aide dummies altogether, haying taken care to put one of the largest logs
in doorway as explained above. Open No. 7, and treat as No. 6 has been
treated (a little burning fuel can be drawn from one of the fines to start the
fire in each case), treat No. 8 as No. 2, and No. 5 as No. 4, and continue
this system throughout, the first two fines being always fired fairly hard,
the next two very easily, the next two in doorways only. When No 2
is ready for dosing, bnrn the damper and remove the chimnies to next
chimney space, but some hours before this, the bricks between No. 1
and No. 2 chimney should have been slightly heated, by two or three floes
in each set of five being slightly fired with small stuff, so as to drive out
the steam, which may be allowed to escape from the chimney opening be-
tween the two dampers, the flues next to the dampers should not be fired,
or there is fear of their getting burnt before their time. The object of
this is to avoid stoppage of draught when the chimnies are moved, and
have between them and the firing a mass of cold, damp bricks for the
draught to work its way through.

Always take care to have every opening closed between damper and firing,
not omitting the top. Move the chimney again when the farthest firing
flue from it is 15 fines off, and continue this.

When No. 81 flue has been closed, open No. 1 flue for draught; when
No. 82, No. 2, and so on, all the back flues beyond 80 from the firing
being kept open ; if at any time the draught seems slack, open the 20th
back flue from firing, if this does not effect a cure, open the 10th or
even the 5th, if the draught cannot be established, (a most improbable
contingency,) close these odd ones again, one by one, as the draught
increases, the 5th first, the 10th next, and so on.

When 50 flues have been closed, knock down cross wall and commence
unloading, but never let the unloading approach nearer to the firing than
50 flues.

If tiles are to be loaded, they should take the place of the 2nd, 3rd and
4th layers from the top brick fiat. The rows of tiles need not be coin-
cident with those of the bricks, and they should be apart an average
distance of 1 J inches, the tiles requiring the least burning, being at sides
of kiln, but at least four inches away from them. When tiles are loaded,
the longitudinal rows of the top bricks should be set six inches apart, or
such a distance that a brick will just span from the centre of one to the
centre of the other.

PATENT COMBUSTIBLE DAMPER FOR BULL'S K1LN8. 391

The average percentage on the 20 lakhs above-mentioned was 70 of
1st class material,4 and 93 of 1st and 2nd class or serviceable tiles, the
principal loss on the latter being due to over-firing. The fully burnt
bricks measured 9|* X 4\¥ X 2|" — the tiles were large 15* Allahabad
pattern. It will perhaps be observed that whilst the percentage of 1st
class material is not high, that of the 1st and 2nd class tiles is very high
indeed. In burning tiles, the bricks must to a certain extent be sacrificed
for them, as if the bricks next the tiles be only slightly overburnt, the
tiles are sure to be bent and worthless, the reason for making the sacrifice
being that the kucha material of the former costs only one-sixth or one-
seventh of the latter. When only bricks are to be burnt, an even lower
kiln is recommended, say 4& feet. In the former Article, the plan is re-
commended of dropping down charcoal on to the binder bricks through
earthen pipes, set at the top of the kiln. A plan just as effective and much
cheaper is cutting up thin branches into short traight pieces, and drop-
ping them in the place of the charcoal. The regular firemen can cut the
branches tip when not employed in firing.

The cost of the kiln five feet high should not be more than Rs. 250.
This with the royalty of Rs. 250 on the kilns, is 3 annas a thousand
on 30 lakhs, which at a low estimate can be outturned in one season.

In the original plan of working, not less than 5,000 cubic feet of wood
are used per lakh, and putting a maximum expenditure of 3,800 cubio
feet (the example noted above shows only 3,523, a large proportion of
which was only branches) on the method of working with the damper,
there is a saving of 1,200 cubic feet, which at Rs. 8 (an ordinary rate) per
100 cubic feet, amounts to Rs. 100 per lakh, or one rupee per 1,000.

The dampers with royalty cost 3 annas per 1,000, so that the actual
saving in using them is 13 annas per 1,000.

In an ordinary flame kiln, the average expenditure is 6,000 cubic feet

• Being naturally biassed towards the kiln, the writer has stated plain facta only, and avoided as
far ae possible, all questions in ita favor about which opinions might differ. Had he stated that the
working, of which some detail has here been given, was to a great extent purely experimental,
(principally as regards height of kiln, and method of firing,) and therefore the results not so good aa
they otherwise might hare been, the statement might have been taken with some reservation. Bnt
shortly alter completing and despatching the Article he gave over charge of the operations. Real-
ly definite conclusions had only been come to a few weeks previous to this, and during these weeks
the percentage of good outturn increased very considerably. Reports received since, show that the
officer who assumed charge with but a slight acquaintance with the kiln, secured on seven con-
secutive lakhs an average outturn of 83 per cent, of 1st class material, with an average expenditure
of fuel of 2,71<) cubic feet large stuff, and 390 cubic feet branches, or 724 maunds.

892 PATENT COMBUSTIBLE DAMPKB FOB BOLL'S KILNS.

of woody and 85 maunds charcoal, costing at the rates of Bs. 8 per 100
and one rupee per maund, Rs. 515, or per thousand, Rs. 5-2. The cost of
fuel by the method here proposed is Rs. 8 per 1,000 — adding to this the
cost of kiln and dampers of 6 annas, (8 annas for kiln, 8 annas for damp-
ers,) makes a total of Rs. 8-6, or Rs. 1-12 less than the cost in ordinary
flame kiln. No acconnt is taken in this of • the cost of an ordinary flame
kiln. To outturn 80 lakhs in a season, at least four kilns would be
required, costing Rs. 200 each, or Rs. 800 the four. This is about 4
annas a thousand on the 80 lakhs, or actually more than cost of a patent
kiln with royalty. Referring again to the damper — the saving caused
by them is so direct as to show itself in even preliminary operations.
A stock of fuel must be laid in before operations commence, and instead
of purchasing 5,000 cubic feet of fuel, at a cost of say Rs. 400, 3,800
cubic feet cost Rs. 284, and five dampers costing Rs. 19, total Bs. 303,
is all the need be procured per lakh of bricks required.

The Agent for the Patents is Mr. A. H. Bull of Sahibgunge, E. I.
Railway, brother of the patentee, to whom all references should be made,
which will be promptly replied to.

H. B.
Agra, 1

6M April, 1876. J

CONCRETE BRIDGES. 893

No. CCIX.

CONCRETE BRIDGES,

By Lieut.-Col. H. A. Buownlow, R.E., Supdg. Engineer, Irriga-
tion Branch, Punjab.

Abstract of Report on Construction oj Concrete Bridges in the 3rd
Dioision, Bari Doab Canal.

The following notes hare been almost entirely taken from a report furnished by
Mr. J. Doyle Smithe, Executive Engineer, 3rd Division, Bari Doab Canal.

The report was a long one, and gave much information possessing merely a local
interest, bnt scattered through it were the results of Mr. Smithe's experience on works
in which I had taken very mnch interest. The abstract was made at first entirely
for my own use, and it afterwards occurred to me that with a few additional remarks,
it might be useful to the officers of the Irrigation Department in the Punjab. I
have now been asked to let it appear in the Professional Papers, but I am very unwill-
ing that it should do so, without my mentioning prominently the name of the officer
who really gathered the experience, and to whose watchful supervision the success
of the works is entirely due.

Kunkar for Lime. — Beaten and screened from earth ; burnt in clamps
with upla) or in kilns with charcoal ; latter method being preferable if
charcoal can be obtained at reasonable rates.

Kunhar Lime. — Picked free from ashes if burnt in clamps ; beaten with
thdpis on a brick floor, and unburnt pieces picked out ; ground dry under
an edge stone in a common mortar-mill, then laid in a layer over the
ballast. A small proportion of stirkhi or fat lime may be mixed with it
(according to the nature of the kunkar) if thought necessary to improve
the quality of the mortar.

Kunkar for Ballast. —To be beaten and broken to gauge, screened

394 CONCRETE BRIDGES.

washed and thoroughly soaked ; gauge }" for foundations and superstruc-
ture, size of large pea for arches.
Proportions of Concrete-
On* measure of lime to three of ballast for foundations.
One measure of lime to two of ballast for superstructure and arch-
work : a very full allowance of lime being given for arch work :
all measured dry.
Mixing the Concrete.— About 300 cubic feet of cleaned and soaked
kunkar spread in a layer about 6* thick at the bottom of a brick-lined
tank, the proper proportion of lime spread over it, and the whole turned
over with phaoras until thoroughly mixed.

Proportion of Water. — As the mixing of dry lime and ballast goes on,
water is sprinkled over the whole, until it appears a moist crumbly mass.
Best proportion of water is about one-third of volume of lime, or, roughly
a mussuck of water to three cubic feet of lime, taking the mussuck to
contain one cubic foot. Much water fatal to consolidation.

Bamming the Concrete. — Immediately after being mixed, the concrete is
removed and rammed into the work with cast-iron rammers weighing
about 10 9)8. each ; thrown in layers not exceeding 3 or 4 inches in depth,
and rammed down to about 2 or 2£ inches. One man will ram from 10
to 15 cubic feet in the day; — total cost of ramming Re. 2 per 100 cubic
feet of finished work ; 100 cubic feet loose concrete rammed into 50 cubic
feet in block-making ; 100 cubic feet loose concrete rammed into 55 cubic
feet in foundations and superstructure ; 100 cubic feet loose concrete rammed
into 66 cubic feet in arch work.

Pick up surface of a dry layer before putting on another, and keep all
surfaces thoroughly cleaned. The best test of soundness of work is to
pick a hole through the uppermost layer of the concrete and pour water
in from a mussuck. Properly rammed concrete should retain the water
perfectly.

Ram concrete in arches with the ordinary iron rammer of 10 lbs.; thdpii
and mallets do not consolidate it sufficiently.

Rammed concrete to be kept covered with water until it has set hard.

Face Boards.— When rammed in situ, outside shape given to the con-
crete by strong planking, cut or bent where necessary to required curve,
and supported on outside by solid pillars of bricks laid in mud. Two 9*
planks, 2* or 2J* thick, fastened together on outside by battens, will make

CONCRETE BRIDGES. 395

a sufficient depth of mould board. They should be moved up 15" at a
time, leaving 8" at bottom to cover edge of last course.

Centrings of Arches. — Should be very strong and substantial. In 3rd
Division, Bari Doab Canal, they were made of timber resting on sand
cylinders, but where timber is dear, might advantageously be made of
earth well rammed between walls of kucha pucka masonry in the manner
so common in this country. But even.in this case, common hurries should
be laid close together upon the top of the earthen centring to distribute
the shock of ramming the concrete, and every third or fourth kurrie should
project about 3 or 4 feet beyond the face of arch to allow of struts being
fixed for support of face boards. Centrings should not be struck or re-
moved until the arch has set quite hard.

Concrete Blocks. — If the requisite amount of supervision can be given
to their manufacture, Mr. Smithe thinks that concrete blocks are cheaper
and more trustworthy than concrete rammed in situ, considering that
they save much time in fixing face boards and scaffolding, and prevent
any scamping of the work. But I cannot agree with him in preferring
them. They require much care, in making and moving, are very apt to
get broken, and have the corners knocked off. If used for face work
only, and of small size, they are apt to get displaced by the ramming of the
concrete behind them. If large and heavy, they give much trouble in
moving and laying accurately ; while in any case, unless the moulds are
most carefully and strongly made, they soon get so much out of shape as
to render true building most difficult. The amount of supervision required
for blocks would, if given to concrete rammed in situ ensure most
superior work of the latter kind. The best size for blocks if used is

2' x v x r.

Method of ramming Arches* — Mr. Smithe considers experiment neces-
sary to prove which is best method of ramming arches in— -(1), horizon-
tal lay era; (2), concentric rings; or (8), voussoirs. My own opinion is
most strongly against ramming in horizontal layers, and in favour of adop-
tion of either of methods (2) or (8).

Vibration being the great agent of destruction with concrete arches,
it will always be better to have rather an excess of lime than a defi-
ciency, so as to ensure every piece of ballast being entirely embedded in
mortar.

The thickness of a concrete arch should be somewhat greater than that
vol. v.— sKCOirn bkbibs. 3 a

396

OONCBBTB BRIDGRB.

of a brick arch of the same spaa to allow for any reduction of thickness
by weathering of soffit.

The importance of cleanliness, in all the work cannot be over-estimated.
The lime must be picked quite free of ashes ; the ballast must be thor-
oughly washed ; the water used for slaking the lime must be quite pure
and olean; and no sand or mud must be allowed to remain on the surfaces
of finished layers.

While care must be taken to giro water sparingly before the concrete
is rammed, equal care must be taken to keep all finished work thoroughly
soaked until it has set quite hard.

Plastering the finished work will in my opinion be found most advisable.
It irill diminish largely, if not entirely, the ill-effects of weathering,
which are very marked during a severe winter in the Punjab, and will
prevent vegetation from getting any foot-hold on the surface of the work.

H. A. B.

v^:

r-v

DESIGN FOK CANNING COLLBGB, LUCKNOW. 397

No. CCX.

DESIGN FOR CANNING COLLEGE, LUCKNOW.

[ Pitt Plates J J. toLVL].

By Tjcekaram, Head Draftsman, Engineer -in-Chief * Office, Raj*
pootana State Railway.

Description.

This College is designed in accordance of the instructions of the Canning
College Committee. The character of the building is general keeping
with the architectural features of Eaisur Bagh and Saudut Alii Khan's
tomb. The details have been taken from some of the best known and
admired types of Indian buildings. The aim of the designer has been to
design a building as nearly as possible correct in style and detail, of strict*
ly oriental character.

The accommodation consists of one centre or examination hall 10CK x
45', on left side of which is a library room 47£' x 28', and two
rooms each 24£' X 22', one for the Principal, and the other for an office.
On the right side there are four rooms, each 24£' x 22', one for a European,
the other for a Native, Professor, and the other two for graduates, and
eight class rooms. The rest of the class rooms are provided at the back,
and a passage 10 feet wide separates them from the examination hall and
the other rooms.

A verandah 10 feet wide is provided all round the building, in the
corners of it, it is contemplated to place bath and store rooms. These
rooms are carried out into baradarees on the upper story, — there is also
a large carriage porch at the front of the building, and another porch at
the back. A passage 10 feet wide connects the examination hall with

398 DESIGN FOR flAHNING COLLEGE, LUCKNOW.

the porch ; and two small porches are provided on either ride opposite
the corridor or main passage.

Specification.

Excavation. — The earth to be excavated until a thoroughly firm and
secure foundation is obtained. All (inequalities to be dressed off, and the
whole made perfectly level, both longitudinally and transversely.

Concrete in foundation.— A bed of concrete two feet deep, composed of
two parts of broken stone and one part of mortar thoroughly watered and
rammed in 6 inch layers, is to be provided under all walls. The bed of
concrete is to extend six inches beyond the footings of foundation on
each side.

Masonry in foundation. — The masonry or brick over the concrete is
to be built of the best description manufactured at Lucknow, and properly
and securely bonded.

Superstructure. — The superstructure is to be of the best brickwork in
lime mortar. To be built to the shape and the dimensions shown in the
drawings, the masonry to be carried up at an uniform level, and every
course to be carefully levelled, and the face of the walls to be truly vertical.
The bricks to be laid with close joints in the best mortar procurable
in Lucknow. The bricks to be thoroughly soaked in water before laying.
Every day's work to be flooded in the evening, the tops of unfinished
walls to be at all times kept covered with water until they are finished.

The pillars of the four corner baradareesf the oriel windows, and the
upper chutree9 the balcony of tower and chujj&s, to be of sandstone pro-
perly dressed and carved, procurable from either Minapore or Agra, or
any other convenient place.

Steps to be of large pucka bricks well burnt and properly shaped,
and laid on edge in fine lime mortar with close joints. The surface is not
to be plastered.

Plaster and white washing. — The whole of the interior and exterior walls,
including domes, but not the stonework as above described, to be plastered.
The plaster to consist of four parts of best kunkur lime mixed with six parts
of fine stone lime, and the whole well ground in a mill. The plaster to be
laid on as follows :— The joints of the masonry to be first raked out
cleaned and well wetted, the mortar to be then laid with force on the wall
so as to fill in the joints folly, without leaving any interstices, and the

DESIGN FOR CANNING COLLEGE, LUCKNOW. 899

plaster then to be floated on in a layer of £ to 1 inch in thickness, well
wetted and beaten, and worked to a proper face, free from all blemishes and
blisters. Over this a thin coat of fine lime mortar (sundla) made of equal
parts of the best kunknr and stone lime, and well ground, to be floated on,
and properly rubbed to an even surface ; on this surface when dry, three
coats of fine whitewash, made of pure stone lime is to be given, and finished
with an enamelled surface to imitate polished marble.

Faulted Roof of Examination Hall and Library, $c. — To be of large
bricks laid in best lime mortar, carefully radiated and summered, and to
be famished with wrought-iron tension rods as shown in drawing. The
skew backs or springing courses to be of Chunar stone. A khoa terrace
three inches thiok, well beaten, to be given over the top of the roof. The
roof of upper verandahs, both sides of hall, four corner baradarees and
towers, to be arched, as specified for examination hall, without tension
bar and Chunar stone springing courses.

Flooring. — The floor to consist of well burnt flat square tiles 12* x 12*
X 1£" carefully shaped and laid in fine lime mortar with close joints, and
the whole rubbed smooth and fair, and the flooring tiles to rest on nine
inches of concrete well rammed.

Flat terrace roofing — to be composed of six inches of concrete (to be
beaten to four) over two layers of 12* x 12" x ltf good pucka tiles, set
in fine lime mortar, the upper layer of tiles breaking joints with the lower
one. The tiles to rest on joists on beams, the former one foot apart from
centre to centre, and the latter varying from 4 feet to 5 feet 10 inches.

The struts and straining beams to be of the dimensions shown on
drawing.

Doors and Windows.— Dooyb to be made of s£l wood in two leaves,
framing 2} inches thick, to be glazed and panelled as shown on the draw-
ings. Each leaf to be hung with four-inch butt hinges, to 5* X 5* s£l
wood frames.

Framing of windows to be two inches, hung with three-inch butt
hinges, to 4" x 4" frames.

Doors and windows to be provided with proper bolts and fitting, and to
be painted with three coats of the best oil color.

Cornice, &c. — Cornice mouldings and ornamentations of exterior and
interior, to be done in the best lime plaster, finished neatly to the exact
shape shown on drawing.

400 DE8IGN FOR CANNING COLLEGE, LCCKNOW.

RaiUng.— ^Bailings are to be provided for the upper front doors, partly
of wood, and partly of wrought-iron, the whole to be painted with three
ooatsof the beet oil color.

Ventilators. — Galvanized iron ventilators will be provided for each room;
all ventilators should be covered by wire netting to keep ont birds, Ac.

Skylight. — Glazed skylights to be provided for light and ventilation
as follows :—

One-large in Native Professor's room.
Six small in corridor.
Painting and Vanishing.— All the woodwork, sunshades, doors, win-
dows, &c, &c, to be painted with three coats best oil color.

Fireplace. — To be constructed in the rooms as shown on the plan, with
flues nine inches square; and the chimney shafts above the roof to have
openings for egress of smoke, and the inside of the flue to be packa plas-
tered smooth and even, so as to leave no crevices.

Sunshades. — Wooden sunshades will be provided and fixed over the
clerestry ventilating windows as shown on drawing. Cast-iron pipe six
inches diameter, to carry the rain water from the upper roof to the ground,
is to be provided.

Woodwork. — All the timber used in the building to be of the best
sdl wood, sound, and well seasoned, and free from shakes, sapwood, large
knots, and all other imperfections to be squarely and evenly sawn, and to
be finished to the exact dimensions shown on drawing.
The scantlings of the beams, &c, as follows:—
Beams for room 22 feet, span 5 feet from centre to centre, 12* X 10'
Struts and straining beams for room 22 feet, span 5 feet

from centre to centre, V X 7*

Beams for 24 feet 8J inches span, 5 feet 10 inches from

centre to centre, ... ... 13* x 10*

Struts and straining beam for 24 feet 8} inches span, 5

feet 10 inches from centre to centre, 8* X 8*

Beams for 28 feet 7 inches span, 5 feet 10 inches from

centre to centre, ... ... 14* x 10*

Struts and straining beams for 28 feet, 7 inches span, 5

feet 10 inches from centre to centre, 8* x 8*

Beams for 20 feet span, 4 feet from centre to centre, 12' x 9"
13 „ 4 „ „ 10" X 7*

DESIGN FOR CANNING COLLEGE, LUOKNOW. 401

Bargbas for span of 5 feet, 1 foot from centre to centre, 2|" x 8£"

„ „ 5 „ 10 inches „ „ 2±* x 8*"

>> » * » +v » 9i w 2 x 2$"

Kurreeff „ 10 „ 10 „ „ „ 3f x 5±"

Abstract Estimate.

C ft. BS.

25,308 Concrete in foundation, including excavation, at Rs. 11 per 100, 2,783

54,554 Packa masonry in foundation, at Rs. 16 per 100, • • . • 8,729

32,099 „ „ in plinth, at Ra. 18 per 100, 5,778

1,99,051 „ „ in superstructure, at Rs. 24 per 100, .. •• 47,772

9,553 Arched roof, at Rs. 80 per 100, . • 2,866

1 1 ,1 13 Vaulted roof of Examination Hall and Library, including cent-
ring, at Rs. 65 per 100, .. .. •• .. .. 7,223
a. ft.

1,82,402 Pucka plaster, at Rs. 4 per 100, 7,296

23,752 Tiled flooring, at Rs. 10 per 100, 2,875

20,010 Terrace roofing, at Rs. 12 per 100, 2,401

8,024 Doors and windows, at Rs. 1 per foot, 8,024

eft

2,259 Chtmar atone, at Ra. 0-14-0 per foot, 1,977

1,707 Sandstone, at Rs. 2 per foot, 8,414

Ko.

68 Sandstone pillars, at Ra, 10 each, 680

eft

4,788 Sal wood, at Rs. 1 -12-0 per foot, 8,879

r. ft

82 Large cornice, at Rs. 2 per foot, •• • 64

829 Small cornice, at Ra 0-6-0 per foot, . 811

aft

211 Hand railing, at Rs. 0-12-0 per foot, 168

No.

52 Ventilator*, at Rs. 1-0-0 each, £2

1 Large skylight, at Rs. 20, 20

6 Small skylights, at Rs. 8 each, 48

88 Sunshades, at Rs. 8 each, .. •• U*

r.ft

880 Castriron pipes, at Rs. 0-12-0 per foot, 660

Mds. srs.

68 37 Wrought-iron tenstion bar, at Ra 13-0 per maund, • • • • 881
No.

3 Oilted copper pinnacles or cullis for upper chutree, at Rs, 60

each, •• .. 180

Qurried forward, .. 1,12,185

402

DR8IGN FOR CANNING COLL KGB, LUCKNOW.

Out Offices.

Brought fonrmrd, .. 142,135

c.a

854 Concrete in foundation, at Ba, 10 per 100,

5,992 Packm masonry, at Ba. 16 per 100, 969

a. ft

2,385 Packa plaster, at Ba. 2-8-0 per 100, 721

1,022 Terrace roofing, at Ba. 11 per 100, 112

110 Batten doors, at Ba. 0-8-0 per foot, 55

eft

145 Woodwork, at Ba. 1-8-0 per 100, 217

Total, .. 1,14*284
Contingencies, at Ba. 5 per cent, .. •• •• 5,714

Grand Total Rupees, 1,19,998

The above is the Specification and Estimate of the Design (illustrated
in Plates LL to L VL) which was chosen and approved by the Committee
appointed to select a design for the New ' Canning College' at Lacknow,
from among a large number which had been submitted by competitors, in
accordance with an invitation issued by the Committee.

PLATE LV

«0

"^"

p
<
>

PLA TK L VI

t3~ ■-

UJ *£
CD 2

ta^n:

O
ui

Z
0

>
lil

SLIDE-RULE FOR FINDING SCANTLINGS OF TIMBER FOR FLAT ROOFS. 408

No. CCXI.

SLIDE-RULE FOR FINDING SCANTLINGS OF
TIMBER FOR FLAT ROOFS,

[ Vide Plates LVIL and LVHI.]

By Lala Ganga Ram, C.E., Asst. Engineer, P. W. D., Punjab.

The practice hitherto has been to calculate scantlings both from strength
and stiffness formal®, and to adopt the larger results ; and this is the true
method to ensure economy of material as well as proper strength and
stiffness.

To facilitate tedious mathematical calculations, many ingenious hints and
tables have appeared, but they have proved to be of very little practical
value. To achieve this object, I have reduced the well-known strength and
stiffness formulae to graphic form, shown in Plate LVIL, which cut on
boxwood or cardboard, will become a Slide Rule, and will be the quickest
and most accurate way of finding scantlings with reference both to strength
and stiffness.

The scales claim advantages, in — 1st, their general scope, being appli-
cable to any description of wood, with any coefficient, and for any ratio
of b to df— 2nd9 Rapidity and facility of their working, — 3rd, certainty
of results against the chance of arithmetical errors, which the ablest
men are apt to make, (though experience does generally lead to their
detection when the results are far from what may bo expected.)

For the above reasons, the scales (cut on boxwood or cardboard) are re-
commended for adoption in Departmental use, and are hereby brought to

VOL. V. — SECOND SERIES. 3 H

404 SLIDI-RULI FOB FINDING SCANTLINGS OF TIMBSR FOB FLAT BOOF8.

the notice of Engineers in different provinces. Instead of the calcula-
tions now called for from divisions, a simple memorandum baaed on these
scales on the following, or some such form, might answer the purpose.

Memorcmdum of Scantlings proposed.

Name of timber.

Span in feet.

Spacing from centre to centre.

Weight per superficial foot.

Coefficient of transverse strength.

Coefficient of deflectional elasticity (Roorkee E).

Scantling by strength formula as per scales.

„ DV*UUWO „ „

Scantling proposed.

Signature.

The scales would, moreover, be of very great use to Civil Officers,

who, with little or no professional knowledge, have to deal with works

of construction, and for finding proper scantlings are obliged to refer

to some Engineer Officer, or to depend upon common mistris.

Investigation of the Scales.

As above stated, the scales are only the modified graphic form of the
usual and well-known

Strength formula, W = jj;Pb, (1).

Stiffness „ a=|H, ; (2>

Where W — working load in lbs. distributed.

pb = coefficient of rupture or transverse strength.
L = length or span in feet.
b = breadth in inches.
d = depth in inches.
$ = factor of safety.
2 = central deflection in inches.
E = (Roorkee E) coefficient of deflectional elasticity in pounds per

square inch.
s has been assumed at 10.

2 has been assumed at -^j.

fOFS-

\titahutfr

fLATE LT1I.

■mm

UI1itm;itiij,

30 IhjKk »• «K«U

-wm\m "-

8MDB-RULB FOR FINDIHG 8CANTLIS08 OF TIMBBB FOB FLAT HOOFS. 405

Note,— Any other values than the above are of very unfrequent use,
bat the scales are equally applicable to any other values, as will here-
after be shown.

1. Strength formula—

*-/&* «•

W = LW, where

W = load per running foot,

as weight per superficial foot X spacing from centre to centre.
/. formula reduces to

"" "* 10

xl"

Let b = rd

.\ 5 J/W'

=3 rtPp*

•#-l M 600

= Vx-

too

100

A 8 log tf - { log J- + log ^} « 2 log L + log

.Mogd-iJlogL+log^.} =|logL + ilog^

Henoe the construction of strength scale. On scale A are marked on the
right, divisions of span in ratio of }rds of logs, on the left, different loads
per running foot in ratio of £rd of logs. On scale B is marked the
logarithm scale to read d (depth in inches)

£ log h i log | (generally used value* of y ) J

2. Stiffness formula —

* - sin w

As above
W as W'L-

b as rd

. • 5 WU

• For other Yaluei of r aepanto Boato O to attMhtd.

406 SLIDE-BULB FOR FINDING 8CANTLIHG8 OF TIMBER FOB FLAT BOOT*.

• • 40 "" 8 nf1 £
26 WL9

# * 1 2600 ^ * 100
r X £

... 4 logd- {10^^ + log ±] = 3 log L + log^

/•logd- Jilog?§? + ilog±} = |logL + ilog^

Hence the construction of the stiffness scale, exactly similar to tb4
described above for strength scale.

To render them applicable to other values of * and 3 than those av
sumed, we refer to oar original formulas, wherein s and Z are to deal
with coefficients, and therefore any other values can be converted into
assumed values by changing p* and E proportionately (vide Example).

Method of using the Scales.

Place the coefficient mark on scale B, against load mark on A, ad
against the span mark on A, read depth in inches on B, the result

2 2

pre-supposing that & = -dorr = -. For any other value of r, » «p§-

rate scale 0 is attached, to which take the reading just found on safe B,

and set it against =• mark on scale C, and against the mark of reqmred

value of r on 0, read depth in inches on B.

The scales can be as well used to find any of the following— speiir
coefficient, weight, spacing, or depth, if the remaining data be given.
The following example will best illustrate the whole.
Find the scantling of a beam required to roof a room of 16 feet span,
placed 5 feet from centre to centre.
Given —
Weight per superficial foot = 80 lbs.
Wood = deodar.
Pb = 500.
E = 2,500.
s and i ss as usual.

;

PLATE LVIIL

:*i

.-»;

■X'

o *

--I

>P*E

8LIDK-SULR FOR FINDING SCANTLINGS OF TIMBBB FOR FLAT ROOFS. 407

1st. By Strength Scale— Plate LVIII.

Scantling required by strength formulae 11*5 x 7 which reduced (if
required) to different values of r by Scale C.

We get 10 x 10, 11 x 8*, 11-8 X 8 J, 11± x 7f , 11% x 7-4, 12-2 x 6-8
or 12-7 x 6-35.

2nd. By Stiffness Scale— Plate LVIII.

Scantling required by stiffness formula rr 12*5 x 8*3, which reduced
(if required) to different values of r by Scale G.

We get 11-8 x 11-8, 121 x 9-1, 12-3 X 88, 12-5 x 88, 12-8 x 8,
13-1 x 7-3, 13-6 x 6-8.

The proper scantling therefore, with reference to strength and stiffness
as well as economy of material, would, under the given conditions' be
13" x 8".

Now, in the above example, suppose « = 6 and 2 = —, then instead of

using coefficient marks 500 and 2,500, use ( ^0 x lOaBsumedvalnex and

\ 6 required value /

(

required

2500 x -55- required value \

£—21 J and corresponding to these coefficients find the

40 assumed value '
depth by following the same method.

G.R.

408 MEMORANDUM ON THE IBRIOATION DUTY OF WATSB, ETC.

No. ccxil

MEMORANDUM ON THE IRRIGATION DUTY OP

WATER, AND THE PRINCIPLES ON WHICH

ITS INCREASE DEPENDS.

[Pufc Plate UX.]

By J. S. Berrsfoed, Esq., Executive Engineer.

DaUdAugut, 1875.

Theoretical Duty of Water. — Theoretically, one cubic foot of
water running for a month will cover an area of 60 acres to a depth of

one foot (80 x 24 x 60 x 60 x 1 = 2,592,000, and ?,f|^° = 60

nearly). It is generally said that five inches is a safe allowance for one
watering, and there are experiments to show that this is the quantity
given in well-irrigation. But I am in doubts whether an experiment
at a well made by counting the numbers of churruses of water lifted per
minute, allowing so many hours' work per day, and measuring the field
in the evening, is a very reliable one. I think more than two or three
inches is seldom given in well-irrigation.

Depth of Moistened Soil — There is a field of average loam a few
hundred feet east of Mankri chauki, which had been ploughed before the
present rains set in. The field is level, and has a high ridge all round it,
so that no water came from adjacent fields. On the 25th July, we had
a fall of 5*5 inches gauged at the Mankri chauki. This fell between 2
a.m. and 12 p.m. (in ten hours). About 5 p.m. the field in question re-
mained covered with a film of water on an average 1*5 inch deep. Several
holes were dug at this time, and the measured depths of the moistened soil
down to the hard dry stuff were from 16 to 18 inches. The depth in other
fields close by, free from surface water, was 12 to 18 inches ; that is, 4
inches (5*5—1*5) of water will moisten ordinary loam to a depth of

MEMORANDUM ON THE IRRIGATION DUTY OP WATER, ETC. 409

16 to 18 inches. A few days previously I had holes dug in well
irrigated fields of the same soil that had been recently watered, and
the depth of moistened earth was 11 to 12 inches. On the 30th, the 1£
inches of water had dried up on the field, and I had more holes dug, one
in a low place, the other where the ground seemed one or two inches
high. The depth of moistened soil at the former was 84 inches, at
the latter 18 inches. What may be gathered from this is, that the
ground soaked the rain pretty uniformly everywhere up to a fall of four
inches in ten hours ; that what fell in excess accumulated in low places
and soaked these to a much greater depth than the higher places. Mo
rain had fallen between 25th and 30th. This fall of 5*5 inches filled
the drainage hollows, and on the 26th several cuts were made in the
adjacent rajbaha and canal banks, and these were flowing till the 8 1st*
The rainfall 12 miles above and 12 miles below Mankri, was 3*1 inches,
and 3*3 inches, respectively. At Bagsar, between 25th July and 4th
August, there was a rainfall of 9*6 inches. One hole dug there in un-
ploughed ground of light loam a few inches above the average level, showed
1 foot 10 inches of moistened soil ; another hole in a lower place, but bound-
ed by a ridge all round, showed 4 feet 6 inches of moistened soil. The
latter plot had been dug to a depth of 18 inches last year. At Dakauli,
between 25th July and 7th August, 14*5 inches of rain fell in the chauki
compound, which is all in grass and not drained. The soil is good, but
sandy. All the water accumulated in the low places, and these were
covered on the evening of the 6th, but dry at noon on the 7th. In one
low place a hole was dug over 7 feet deep, and down to this point the
ground was quite moist ; after this, apparently, the moisture increased
with the depth. Water was poured into the hole to a depth of 9 inches,
but this all dried up next morning. At another place 150 feet off, but a
few inches higher, the depth of moistened soil was only 2 feet 9 inches.
Water in well at Dakauli stands 10 feet below the surface. From the
foregoing, we may fairly conclude that four inches is ample for one water-
ing; that if more is given, it passes into low places and soaks these to an
unnecessary depth, or is evaporated.

At Mankri not a drop of rain had fallen before the 25th July, except
0*3 inches on the 5th, and 0*5 inches on the 9th, which softened the
ground sufficiently for ploughing. Then allowing four inches as the
required depth for one watering, and that in the hottest weather, this is

410 MEMORANDUM ON THE IRRIGATION DUTY OP WATER, ETC.

given only once a month,* even to sugar-cane ; the theoretical dnty of
one cnbic foot per second is 180 acres, that is to say, in the months of
April, May, and Jnne, or our kharlf season of high demand. In the
rabi, few crops get more than two waterings, a great many at tails of
distributaries only one, so that where there is no sugar-cane, (which usually
gets a watering in November or December,) the theoretical rabi duty per
cubic foot, allowing that the watering may be lighter than in kharlf, and
probably about half as frequent, ought to be 820 acres, or the theoretical
duty of water in such divisions as the Aligarh and Etawah, ought to be
500 acres per year. It is not fair comparing acreage duty of the lower
divisions with that of the Eastern Jumna Canal, or the upper divisions
of the Ganges Canal, where sugar-cane and rice are largely watered.
The more correct plan in such cases is to compare the water-rate per cubic
foot, this rate bearing some proportion to the quantity of water used.

Actual Duty. — But the actual duty obtained even in the best divi-
sions is not over 160 to 180 acres per cubic foot, or about one-third of
the assumed theoretical duty. The average duty for the whole canal last
year, (leaving out Cawnpore Division,) taking canal discharges, was 155
acres ; and rajbaha discharges, 189 acres. We have statistics enough to
show what the actual duty of water is, and to see how far it falls short
of the theoretical. The next important thing is evidently to make these
two approach as closely as practicable. No amount of mere discharge-
taking and reporting the result will ever advance us in this direction.
We see from the duties in different places, that old canals give higher du-
ties than new, that certain soils require more water than others, and there
is a happy feeling that some day things will right themselves. This is
true to some extent ; but in the meantime, the matter, I think, admits of
more scientific treatment.

Efficiency of a Canal. — Take the Ganges Canal ; we may look on
it as a great machine composed of many parts, and go about calculating
its efficiency much in the same way as that of a steam engine. This ir-
rigating machine is made up of four important parts which are quite
separate, and, as things stand at present, at least two of them depend on
different interests. They are as follows : —
I. Main canal.
II. Distributaries.

* If oftener, a proportionately leas quantity will suffice, as in well-Irrigation,

MEMORANDUM ON THE IRRIGATION DUTY OF WATER, ETC. 411

III. Village water-courses.

IV. Cultivators who apply the water to the fields.

Each cubic foot of water entering the head of canal is expended as
below : —

1st. In waste by absorption and evaporation in passing from canal

head to distributary head. .
2nd. In waste from same causes in passing from distributary head

to village outlet.
3rd. In waste from same cause in passing along village water-course

to the fields to be watered.
4th. In waste by cultivators through carelessness, in not distribut-
ing the water evenly over the fields, causing evaporation,
and the ground to get saturated to an unnecessary depth in
places.
bth. In useful irrigation of land.
Our object is plainly to increase the 5th by the reduction of all the rest.
Calling D* the theoretical duty of a cubic foot of water delivered at
canal head, we may express its actual duty D for the whole canal as

follows :—

D = C00 x D*, (1).

Where C°° represents the mean efficiency of the Ganges Canal. It was
for 1873-74, taking 500 acres as theoretical duty, equal to £&£ = *31
O30 is obviously the product of four other factors, which may be written
thus—

C00 = C*c x CD x Cw x 0°, (2>

Where Cxc is mean efficiency of main canal.
„ CD ,, „ distributaries.

„ Cw „ „ village watercourses.

„ C° „ „ the cultivators.

Now CMC has been pretty well known for years, and its effect is bo
large, that it will always be kept in view.

For the year 1873-74 it was equal |££ = '82. We may leave it out
of the question at present, and confine ourselves to water entering the dis-
tributary head. The mean efficiency of a distributary system, including
all parts, would of course be the product of the last three factors given
in equation (2), these factors varying with each individual distributary
system. This mean efficiency we have determined for some years past

VOL. V. — SECOND 8ERIB8. 3 I

412 MEMORANDUM ON THB IRRIGATION DUTY OF WATER, ETC.

(vide duties on different distributaries ;) and taking 500 acres as theoreti-
cal duty, it is sometimes as low as 0*25 and 0*20 in this dry division.*

Bat what we have not done yet is to analyze the loss on a distributary
system. Going back to the term efficiency, which is convenient, we shall
see that the efficiency of water entering a distributary head is different
for each field watered ; and it is the investigation of this in detail that
I think will show the subject in a new light, perhaps lead to greater eco-
nomy of water. The efficiency of water entering a distributary head to
water a certain field from a certain outlet may be called G. Then the
duty of the water used in this field would be—

D= C x D*f (3).

C = C* X O X O, (4).

Where G* is the efficiency of the distributary between the head and
particular outlet, O is the efficiency of the particular water-coarse be-
tween the outlet and the field, and O the efficiency of the particular cul-
tivator who waters the field.

Absorption and Evaporation.— The next point to establish is,
what the nature of the waste called absorption and evaporation is, and what
proportion is due to each course. Take evaporation first. Dr. Murray
Thomson's experiments carried on in the months of April and May, with
a decided hot wind blowing, gave an average result of half an inch is 24
hours, and it agrees fairly with M. Lamairesse's observations in another
part of India, (vide Boorkee Professional Papers for July 1871, pages 42
and 45). This of course may be considered a maximum. Then taking
a distributary 30 miles long, having a water surface averaging 10 feet
wide, the loss by evaporation in 24 hours would be 80' x 5,280' x 10'
X & = 66,000 cubic feet, and as there are 86,400 seconds in 24 hoon,
the loss per second would only be $££ = '80 of a cubic foot; and sup-
posing the area of water surface of village guls equal to twicef the water
surface in a mile of the distributary, the loss by evaporation on all the
glils or water-courses would be *8 X 2 = 1-6 cubic feet, or whole loss by
evaporation on a distributary 30 miles long with its village water-courses,
would be a little over 2*5 cubic feet per second, or about 5 per cent, of
probable discharge. We see, then, that evaporation is not of much con-
sequence as far as the different channels are concerned, even in the
hottest weather, and may be neglected in the rabi season. The chief

* Anapahahr Branch.

t Protatbly one-hall or more of tnegtUawotUd be In UUI,

PLATE LIX.

t*4

*X\

>, ^

1 : • • -

i£

a ifi'

**:

\ »

» • 1 I

# / <

tit t t

• i . I

• ' • 9 ' J

.* '''■'•

:,.--V • /'

* >

•■*

o
to

MEMORANDUM 019 THE IRRIGATION DUTY OF WATER, ETC. 413

part of the loss most, therefore, he due to percolation and absorption.
These two terms differ considerably. The former may be said to he due
to gravitation, the latter to capillary attraction.

Absorption is a more complicated process than percolation. The latter
takes place throngh boulders or coarse gravel in precisely the same way
that water issues through pipes or strainers in the bottom or side of a
vessel ; and the quantity discharged per second throngh a bund of boulders
and gravel will depend on the size of the interstices of the stones, their
number, the thickness of the bund, and head of water. The thicker the
bund, the longer and more broken up the channels of escape will be, and
hence the more friction ; but the question of discharge depends on the
same principles as does the discharge through pipes. If the boulders and
gravel are broken into fine sand, and the bund formed of this material, the
principles of discharge are quite changed : the interstices now become so
small, that they act in the same manner as capillary tubes. If empty, the
water rushes in and fills up the cavities, and if the particles are fine
enough, rammed sufficiently close together, and the bund of a certain
width, the water is retained in the cavities with greater force than that
due to the hydrostatic head in pressing it through. The force that thus
holds the water in the interstices of the sand is termed capillary attrac-
tion or capillarity ; and although it may be one and the same thing as grav-
itation in reality, in matters of engineering we may regard it as a quite
separate force. We have only to deal with results, and we know gravity
is a definite force depending on the mass affected, and that to us on the
earth its resultant acts in one definite direction. We similarly know that
capillarity acts equally in all directions, vide its operation by absorption
in a homogeneous porous substance. If a vertical hole is bored in a hori-
zontal bed of soft sandstone, and coloured water poured into this, it will
be absorbent by the stone, and spread regularly all round the hole. We
may conclude, therefore, that in such a position the force drawing the
water into the stone acts in radial directions all round the hole. How
gravitation affects its diffusion in a vertical direction will now be shown.

Fig. 1 (vide Plate LIX.J represents a channel in a gravel soil or one of
very coarse sands, the blue dots indicating the manner water would trickle
through the ground, each bit of gravel or grain of sand splitting the water
up, sending it right and left, (vide Fig. 10,) and diffusing it laterally as it
descends. Fig. 2 represents what would I should say take place if gravity

414 MEMORANDUM OH THE IRRIGATION DUTY OF WATER, ETC.

were suspended and merely absorption in play, and the Boil homogeneous.
The attraction for the water would be uniform, and act approximately
radially round some central point in the cross section of stream, about
which point therefore the water would be symmetrically diffused. Bnt
gravity, which is always in play, modifies this capillary action, so the water
has actually to follow the resultant of two forces,— one, uniform attraction,
which we may call af in the radial directions indicated by dotted lines on
Fig. 2, and the other gravity, or gy also a uniform force, but in a vertical
direction. Fig. 11 will explain this action, where the blue arrow repre-
sents the distance to which capillarity would carry a particle of water at
the bottom and sides of channel in certain intervals of time, and the yellow
lines a similar measure of gravity in equal intervals. It is seen by find-
ing the resultant of these forces, that the portion of soil saturated in a
certain time would be represented in cross section by the blue dotted line
on above diagram, or coupling this action with that indicated in Fig. It
the result is shown by the blue lines, Fig. 3.

I have heard it observed that if absorption were so bad as represented,
it would make itself very visible in high embankments. But this is
usually not the case, for which I think there are two reasons : the first,
and most practical, being that the soil in low places is much more clayey
than elsewhere, and here only we have high embankments ; the second
reason is that absorption ceases when the absorbing medium is limited.

Thus in Fig. 4, which represents an embanked channel, the medium
stops at the outer slope, and only what is evaporated is made good by
absorption through the slope, or if the bank is wide, the slopes are beyond
the zone of absorption. The bed and base of embankment absorb,
however, as in any other case. This is why a bund of pure sand can dam
up water at all. Take a bank of sandy soil, (as represented by the yellow
shade in Fig. 5.) If a hole dug in it is filled with water, this will dry
up in a few mordents; but spread a layer of blue clay on the ground
(Fig* 6) and make an enclosure with the same sandy soil, rammed to the
closeness of the natural bank, and fill it with water, the water will not
decrease beyond what the banks at first soak up. In Fig. 5 the medium
is unlimited. In Fig. 6 it is limited to the soil in the ridge.

A very simple experiment that will show this in a remarkable manner
is to close pretty tightly the mouth of a full surcd or bottle with a small
piece of sponge. The surai may then be turned on its side or upsid>

MEMORANDUM ON THE IRRIGATION DUTY OF WATER, ETC. 415

down {Fig. 7) if the sponge is fixed tightly enough not to be blown ont
bodily. The sponge will become quite saturated, but, unless pressed or
touched with the finger, will giro out no water. But place another large
dry sponge in contact with it (Fig. 8) and the water at once begins to
flow through the sponge in the neck of the surai, and goes on until the
second sponge can absorb no more, it is a very striking instance of what
1 have been discussing ; the question, too, is evidently one of great im-
portance in considering loss by absorption.

Referring again to Fig. 3, it will be seen that a layer of earth next the
wetted perimeter first gets saturated, then the next, and so on ; the layers
increasing in extent as they go farther away, and therefore, on the as-
sumption that the current goes on uniformly, the farther off a layer is
from the wetted perimeter, the less highly it is charged with water, until
the limit comes at some line close to, but above spring level, and below
which the ground is saturated by capillary attraction from below upwards ;
but attraction in this direction is limited in its range on account of gravity.
We may then fairly conclude that it is the layer next the wetted perimeter
which limits the quantity absorbed ; that the greater is its area, the more
will it pass through to the still greater area of the next layer. In short,
we may say absorption, everything else being the same, varies as the wetted
perimeter, so that if through a certain section of a raj bah a, the same
wetted perimeter were preserved, the loss per mile by absorption would
simply be constant and independent of the discharge. In practice, there-
fore, for sections of small length, we may take the loss at so much per
mile. But in general we know that the discharge and wetted perimeter
decrease with the length, but the latter not nearly in the same proportion
as the former. However, we shall probably never be far wrong in as-
suming that the wetted perimeter varies indirectly as some function of
the length ; or putting it another way, that the total loss up to any point
is the loss in the first mile multiplied by some function of the length.
It will be found that this function may be of the form L* when L is the
length in miles, and z an index usually less than unity. In some cases
I have found it equal to $ths. It will now be seen that the loss up to
any point may be found when the loss between two certain other points is
known. But the efficiency of a rajbaha at any point is the fraction
whose denominator is the discharge at the head, and numerator this same
quantity, minus the loss down to the point in question ; or if W represents

416 MEMORANDUM ON THE IRRIGATION DUTY OF WATER, ETC.

the total waste down to any outlet, Q the discharge of rajbaha at head,
and 0*° the efficiency of the rajbaha at that point, then —

O = ^ = 1 - J (5).

Bat as already shown, the waste down to any point may approximately
be expressed as the product of the loss in first mile, and some function of
the length, or

W = AP x L*, (6),

or substituting in equation (5), we get

C*>= 1 - — q— , (*0,

Where Q is the discharge of the distributary at head, AP the ascer-
tained loss by absorption and percolation in first mile, and L* some
function of L, which will be found by experiment to be about L to the
power £ ths or f ths in most cases, but near the head of distributary L1
or simply L. Similarly taking I as length of village water-course in

furlongs, q its discharge, and I* a function of I of the same nature as Ls
is of L, and ap the loss in absorption in first furlong, the efficiency of the

water-course can be written —

0= i _<Z*L?!, (7).

The efficiency of the cultivator O varies within wide limits, say, be-
tween *5 and -9 where unity represents his efficiency at well-irrigation,
which is practically the theoretical limit. Now for an outlet at the head
of a distributary and irrigating fields quite close to the outlet Lso,
and I ss o, and therefore second terms of equation (6a) and (7) Ttnish,
and C*0 and O, become each equal to unity, and there is no loss but
what may be due to O, which is always less than unity, except, perhaps,
in the case of lift-irrigation. This is one extreme ; the other is where
either L or 2 is so great, that the second term of (6a) or (7) becomes
equal to unity, then 0° or O equals 0. These would be condition*
under which water would just either reach the outlet or field, and no
more. This I have seen more than once, and there are places where a
fairly large kulaba in a whole week only irrigates two or three fields.
An application of these rules to an ordinary case is this. Say discharge
Q = 50 cubic feet, that the outlet is at 10th mile ; and so L = 10 ; the
loss from percolation, <&c, for this line being 1'25 cubic foot in 1st mile,
and X = $. The discharge of water-course q = 1 cubic foot, I =: 6 furlongs,
and ap = «03 cubic foot per furlong (nearly J cubic foot per mile)—

MEMORANDUM ON THE IRRIGATION DUTY OF WATER, BTC. 417

ThenO = 1 - 128 * 10> = 1 - ^^g-8^ -829

Oil 00

O = 1 - ?*^Li! = 1 - -18 = -820

Cc =3 say = -75

and C ss -829 X -82 x -75 ^ *53

Or leaving out the cultivator, *829 x *82 = *68. That is, for each
cubic foot entering distributary head, only -68 cubic foot is available for
fields opposite the 10th mile and 6 furlongs off. But what will be
available at the tail of a long village water-course, taking out at the 20th
or 30th mile of distributary ? (We require more experiments to find X
for this case, which we have taken as equal to £ ths in the example).
However, one thing is quite obvious, no matter what the actual amount
of loss is in either distributary or water-course, it varies in some direct
proportion with L and I, Another equally obvious fact is, that the loss
varies directly as AP and ap, the loss per mile and furlong in each case.
Also that waste is due to the cultivator if he is careless.

Remedies for present defects, — Now what can be done, and what
has been done, in the way of remedying or lessening these defects. The
distributary of to-day is the same as that of 20 years ago, as far as
construction of the channel is concerned, and I think it can be shown
that the improved method of alignment is against its irrigating ef-
ficiency. The village water-course is in most cases neither constructed
nor attended to in any way by the engineer, and as a rule is badly aligned,
badly constructed, and not maintained. Unless the banks breach and
cause visible waste of water, the owner is never interfered with. The cul-
tivator is the only part of the machine that has been improved. This
partial improvement was effected some eight years ago by an order enforc-
ing the making of kyaris as in well -irrigation, which if vigorously carried
out, would increase duty considerably in flow-irrigation. In lift-irrigation
O is probably unity, and this goes far to give a high duty in divisions
where there is muoh of this kind of irrigation. I believe the widest field
for improvement is the village water-course ; they are certainly on an
average 25 per cent, longer than need be, owing to avoiding certain lands.
They often run long distances through sandy ground which absorbs a
great proportion of water against which there is no provision in the con-
struction of the water- course. The size or discharge of the kulaba is fre-

418 MEMORANDUM ON THE IRRIGATION DUTY OF WATER, ETC

quently not suited to the length or conditions of the water-coarse. Tiro
or three different water-courses sometimes ran alongside, and thus unneces-
sarily increase wetted perimeter, and consequently loss.

Maps required. — The first thing I should say in all cases is to get a
good map showing each water-course as it exists. This most canal
engineers have long desired, but thought it meant an endless amount of
surveying ; it can however be very easily and accurately done as follows.
An amin, with an ordinary village map in his hand, goes over the ground,
and with a blue pencil traces in each water-course from its head down-
wards. The water-course invariably follows the field boundaries which
. are shown on the map, and can be easily distinguished from their shape
and relative position as in carrying on the irrigation measurements. At
the same time the amln can put in wells, and if a sharp man, the differ-
ent Roils and the boundaries of irrigable or unirrigable land. One or two
villages can be done in a day. The work is much facilitated if the
patwari is present. Having filled in all the necessary lines on the village
map's rajbahawar, you see exactly the nature of the water-courses in each
village, and can go about improving their alignment. These maps are
on a scale of 16 inches to the mile. I have a second-rate draftsman,
who with a pentagraph can reduce two or three villages to a 4-inch scale
in one day. These separate villages fit in wonderfully well, and gire at
once a 4-inch map of the distributary with all the information that can
be desired.

Puddling of Village Ouls. — All village water-courses I think should
be puddled, certainly those through sandy soil. A layer of puddle three
inches thick would do. The course would be properly levelled and dog
one foot too deep and two feet too wide; the puddle would then be applied
all round this section, and nine inches of ordinary earth placed over the
paddle, to preserve it from cracking, and being dug up when clearing the
gul. The latter ought to have a light masonry section at each 500 feet,
and masonry bed levels of a few bricks at each 250 feet. Then in clear-
ing the bed a mistake could hardly be made. The cost would be Rs. 150
to Rs. 200 per mile. This seems a great deal ; but say the length is a
mile, the discharge at head one cubio foot, the loss probably 25 per cent.,
the increase of duty would be 20 or 30 acres of sugar-cane in one kharff.
In places where there is no doubt about the loss being great, capital could
not be better spent than in re-modelling village guls and puddling them.

MEMORANDUM ON THE IRRIGATION DUTY OF WATER, ETO. 419

Rfybaha improvements. — Next, the rajbaha or distributary ; the loss in
the distributary, although not nearly so great in proportion as in a village
gfil, is often very large, especially in new rajbahas. Most of the sand or silt
is dropped in the upper reach of a distributary, but particles of clay or im-
palpable sand are carried to the very tail, and are often deposited on sides
and bed to a considerable thickness, forming a more or less impervious
lining, which however gets washed off a good deal in the rain, or is removed
in the often injudicious operation called berm-cutting. High velocity is
against the formation of a silt berm, and thus indirectly increases absorp-
tion. Near the head of a distributary there is too large a proportion of
sand to render the silt berm water-tight. Also the deposit on the bed
even a long way down is more charged with sand than the berms ; the
sand, being heavier, drops to the bottom and gets rolled along, the lighter
particles of clay adhering to the sides. I have seen specimens cut from
a berm, and from the bed above an expansion fall, that could not be told
from the best blue clay out of a jbll. 1 should not propose puddling the
sides of a rajbaha unless in the first five miles, but the bed might be ad-
vantageously done everywhere to a thickness of six inches. Suppose the
required section was 8 feet bed and side slopes 1 to 1, the bed might be
dug 18 inches too deep and 8 feet wide. At the bottom of this, a 6-inch
layer of puddle laid, as shown in the accompanying section, Fig. 9, and this
covered with one foot of earth, then the water let in. After the channel
had run a year and the banks had become somewhat weathered and fixed,
I should clear it to the original section, and after this never touch the
berms until they had contracted the channel to the theoretical area of
cross section as shown by thick lines in Fig. 9. Masonry profiles built at
every half mile, also the masonry outlets if properly laid out, would show
the theoretical section, or rather what silt berms should come to. In
this way we should secure a fairly water-tight channel. I find that in
some places where well-irrigation is carried on in sandy soil, each time
the leading water-course is cleared, a quantity of blue clay is collected
near the well, and for a few days a man or boy keeps breaking it into
mud between his hands near where the churrus is emptied ; this is carried
forward by the water, and deposited on the sides and bed of the channel
as a thin lining. It is, however, but a temporary measure, but shows
what can be done. It was only lately I heard of this method. It might
be tried on a new rajbaha in very sandy ground, by collecting clay at the

VOL. V.— SECOND SEBIE8. 3 K

420 MEMORANDUM OR THE IRRIGATION DUTY OP WATER, ETC.

falls and haying it thrown in after the channel has been cleared. The
action of the water would break the clay np thoroughly, and carry it in
suspension to the berms and water-courses miles below. Every closure
the main canal deposits a thick layer of clay along the edges, but this
gets scoured away once the supply rises again.

Re-modelling practice. — However desirable it may appear to carry
out some of the changes I have suggested, I do not think it would be
advisable or practicable to do so unless gradually. But there are at
present many cases of re-modelling existing lines and re-distribution of
water, besides the large new canals that will soon be ready, where these
principles might be attended to with advantage. In fact, if the question
of increasing the duty of water is not solved in some form, a great many
of our new canals must be financial failures. Their future profits hare
been calculated on duties that are not obtainable on our oldest canals.
Waste is inseparable from works like our great irrigation canals. But
there are no such physical or practical difficulties in the way, as will oblige
us to be content with the present state of things. It will not do to think
a distributary is fully re-modelled when it has been transferred from a
drainage hollow to the watershed, and supplied with masonry outlets. I
believe by far the most important part remains untouched, if not in some
cases positively injured by such re-modelling. The only effect of oor
present practice is to consider the features of the ground without much
reference to the quality of the soil or its geographical distribution. In
this part of the country the best of the land is in low places, and the
villages, as a rule, are built near good land ; therefore manure and low
ground go closely together; and the ordinary cultivator will not go to the
expense of carrying manure to the upland, not to speak of the soil being
lighter and unsuited to the best kharif crops. He may grow rabi, but the
chief kharif crops there will be raised without irrigation. Say an old dis-
tributary crosses or hugs a minor drainage line, the low land will be covered
with sugar-cane or other valuable kharif crops. The soil through which
the line passes is usually retentive, and so loss by absorption or AP in equa-
tion (6a) is small, and therefore O0 large. Again, for the same reason
in the village water-course ap is small, and owing to the crops being
close to the distributary, I is small, and therefore from these two circum-
stances O is comparatively speaking, very much larger than usual. Pro-
bably owing to the readiness with which water is obtained under each

MEMORANDUM ON THB IRRIGATION DUTY OF WATER, ETC. 421

conditions, O is below the average. Re-model this line according to
present practice, the distributary is transferred to high land, and probably
kept in digging. Owing to this and the soil being light, AP in equation
(6a) is much increased, and therefore Cdo decreased. Again in same way,
ap in equation (7) is increased ; likewise I as the line is now far away
from the heavy crops: hence O is much decreased. Therefore, I am of
opinion that the tendency of the present practice is against irrigating duty.
I do not for a moment say it is not the correct practice : it undoubtedly
is, but it is incomplete, only deals with one element of the case, neglect-
ing two — viz., (1), improvement of the distributary channel to counteract
the greater absorption in excavation and in lighter soil ; (2), the number,
proper alignment, and construction of the village water-courses ; and it
would seem reasonable to at least consider these points before taking
action. Of course much will depend on the general nature of the soil
and habits of the cultivators.

Village Maps utilized.— The village map is a source of information
that I think has been generally overlooked. It is on a large scale 16 inches
to the mile. The principal lines have been surveyed with a plane table
and chain, and a system of triangulation adopted, the details filled in with
the chain, and all subjected to fair checks, so that the result is not bad.
The map gives each field in as much detail as the Ordnance Map of Eng-
land, if not quite so accurately. Every tank or jhfl is shown ; roads, trees,
wells, are usually given or can be put in. Waste land has particular marks,
and the khasra gives the kind of soil in each field according to the classes
fixed on in the settlement; so that in reality, a village map properly
worked out, affords all the information that is necessary with regard to
the land, and this can be put in a graphical form by suitable conventions.
Another bit of indirect information it gives, viz., high and low ground.
After going through a large number of these maps, it will be seen that
almost invariably large fields are only on high and light ground ; that when
the fields are small they are almost invariably in a hollow. The excep-
tions are very rare, and with the help of the village tanks and waste
land, &c, the drainage line of the village can be roughly traced. The
map can be easily reduced with a pentagraph to our working scale of 4
inches, and put together. Borne errors will of course. creep in, but their
tendency is to cancel each other ; and the relative position of places not
too far apart will be practically quite correct. This is all we require. It

422 MEMORANDUM OH THE IRRIGATION DUTY OF WATER, ETC.

matters little whether our map is oat 1,000 feet in the distance of two
places 5 or 10 miles apart. Again in the case of giving outlets on new
distributaries, each Tillage might be asked to give a list of the fields they
intend to irrigate or think likely to come under irrigation ; these might
be marked with crosses in blue pencil, and after other considerations, the
positions of the outlets, the proper alignment of the new water-coarse
fixed with pencil, and the people told that if the outlet is to be given,
this line or one in the same general direction (after approval) most be
adopted. The whole question of whose land it was to pass through
would in this way be fully settled, and the line fixed before digging a sod.
Should there be opposition on the part of some people, the canal
officer would step in and settle the matter under Act VIIL of 1873,
Section 22.

Tatilsv-In speaking of what had already been done to increase duty, I
did not mention tatils, because this is more an administrative question, and
may change with the ideas of every new officer. The same might be said
regarding preparation of kyaris. But they differ in this. No general
orders have been issued, as far as I am aware, on the system of tatfls to
be observed. Definite orders as to size, &c, have been passed on the
subject of kyaris, and the power granted of imposing very heavy fines
if they are not made accordingly. The system of rajbaha tatils is well
understood everywhere, and depends on the principles formulated in
equation (6a), page 416. We see that C*° increase with Q, and decrease
with AP, but it is known that discharge increases in a much greater
proportion than wetted perimeter : hence in rajbahas where AP is great,
G*0 increases very rapidly with Q-, and so if Q is the allotted discharge
per second, there is a great gain in running double this for half time.
But there are practical objections to it in some cases, and so the system
of " kulaba tatils " over certain sections is adopted ; this iB not so ad-
vantageous as far as Cd0 is concerned, the effect is about a mean between
that with a rajbaha tatfl and no tatil at all It makes no difference as
regards O, as the village guls only run alternate weeks, no matter which
system is adopted. Of course the system may be worked in different
ways as regards time, such as 2 weeks in 8, 1 week in 2, or 1 week in 3.
Theory would lead further in this latter direction, but practical considera-
tion limits tatfls to about 1 week in 2. This theory of tatfls has led to
the adoption of fewer and larger distributaries in preference to more

MEMORANDUM ON THB 1BRIGAT10N DUTY OF WATER, ETC. 423

numerous and smaller ones. Bat I think the reasoning has often been
inconsistent. Large distributaries* generally mean long village water-
courses, and I take it that the latter are the most wasteful part of the
machine. There is of course one arrangement that gives a maximum
- result, and this ought to be considered with reference to the terms of
equation (6a) and (7). If the constants were evenly approximately
known in each case, the best arrangement would be simple matter of cal-
culation ; of course bearing in mind that without the lines having some
lengths, there could be no distribution of water, this would be one mini-
mum ; and again with lengths beyond a certain thing there could simply
be no irrigation, all water being expended in waste on the way, this is
the other minimum, and it is our business to arrange the lines so as to
give the maximum effect between these two limits. This is the real
point at issue in determining where a Government distributary ought to
end, and a zemindar's gul begin, keeping in view cost of maintenance.
One other point I have not touched directly, but which might possibly be
included in O, the efficiency of the cultivator is the uniformity with
which he irrigates his crop. On the Eastern Jumna Canal, I believe the
people are so impressed with the advantages of canal irrigation, that they
water once the season begins ; demand is in this way distributed, and
every one gets his water in due time. On newer canals this is not the
case : cloudy weather will sometimes put people off taking water, which
thus actually goes to waste, while the Eastern Jumna is irrigating with
its whole supply. If no rain falls, the demand at once grows intense, the
regular supply is not up to the abnormal demand, the cultivators are dis-
satisfied, and the duty of the water is low for that season. Time will no
doubt remedy this defect in some measure ; the system of tatils on vil-
lage outlets has done much in the way already. Regarding the mere fact
that waste occurs in the main canal, the distributary, the village water-
course, and in the hands of the cultivator, I have stated nothing new ;
but I think the matter has been put in a new light, and its incidence
shown in a manner that admits of closer observation, and shows the re-
lative importance of different sources of loss. Thus, for instance, equa-
tions (6a) and (7) shows two things very clearly that may not have
struck every one before, viz., that a cubic foot of water at the tail of a
long distributary is a much mare valuable commodity than one at the
head. That a man who applies to be let off his outlet tatil because his

* Without proper minors.

424 MEMORANDUM ON THE IRRIGATION DUTY OF WATER, KTC.

gul is bo long that bat little water reaches his fields, should, contrary to a
generally recognised practice, not be let off the tatil, bat famished with
an outlet discharging more water.

Theory of Absorption. — With reference to my theory of absorption,
it is based on observation. If correct, which all the facts I can gather
go to prove, then more waste of water occurs in excavated, than in
embanked, channels. The contrary is the generally accepted theory.
The question is important on sanitary considerations. The land springs
are raised, I believe chiefly with the water absorbed by the ground under,
and alongside, our channels, and not by the water actually spread over the
fields, as if this is given to such an extent as to go down below a certain
depth, it is practically wasted ; and in most soils water so used would ha?e
to remain on the surface of the ground, some time being required to moisten
it to a certain depth. Meanwhile, evaporation, which has so little effect
in causing waste while the water is in the channel, may cause a loss of 20
per cent, or more when the water is spread over the fields. Of course heavy
rain falling on previously irrigated ground more rapidly accumulates on the
surface, and causes floods sooner than if the ground had been dry, bat it
will not soak into the earth unless in fields bounded by ridges on all
sides, or in low places in sandy soil. Once it finds its way to the regular
drainage hollows, the absorption is not so great, the ground there being
dense and clayey. Surface drainage is evidently the remedy ; however,
to be effectual, the ridges bounding village fields must be cat before the
rains. But the absorption through the bed and banks of the different
channels will go on unless these are puddled. If even one-third of the
water of the whole Ganges Canal is going to raise the springs of the
country, or say on an average 1,500 cubic feet per second, and that one
cubic foot of water will saturate three cubic feet of subsoils, (experiments
on the lower green sand near London gave two gallons of water to the cubic
foot of sand in aitH,) then one cubic foot per second would raise the springs
under a square mile of ground to a height of *28 feet in one month, or
3-36 feet in a year; but the loss is probably never so concentrated as
this, and there is a lateral flow towards the lower spring level on each side.
But probably we may say that the loss on the whole Ganges Canal is ca-
pable of raising the springs over an area of 4,500 square miles, to a height
of 1-12 feet in 12 months. Rivers and drainage hollows modify this a good
deal, but the tendency must be to rise unless absorption is stopped.

J. S. B.

FURTHER NOTES ON INDIAN CEMENTS. 425

No. CCXIII.

FURTHER NOTES ON INDIAN CEMENTS.

By P. Dejoux, Esq., C.E., Executive Engineer, Cement Experiments
Division.

Effects of Alkali on Portland Cement— I noticed in previous cor-
respondence that in my opinion the use of alkali (either soda or potash)
in cement made with the proper kind of clay would prove more detri-
mental to it than otherwise. It will certainly increase the cost of the
cement without any real advantage.

I have been induced to dwell upon this point, because my attention was
again drawn to the use of alkali by Mr. Dupeyron, who conducted experi-
ments for Messrs. Ker, Dods and Company, and who fonnd that by
mixing (after calcination) two per cent, of carbonate of soda with the
eement ready for use, extraordinary results in many cases wonld ensue.

His cements, as tried by me, containing an excess of lime, broke when
used pare at a strength of 160 lbs. per l£" X 1£", and when mixed with
two per cent, of carbonate of soda broke at 715J lbs.

These extraordinary results were, so far as I can judge, obtained from
no other cements than those containing an excess of lime.

Certainly to a cement containing the exact proportions with which I
have obtained such high results as 900 lbs. after eight days, the addition
of the carbonate of soda will cause no difference ; but in a cement rich in
lime it seems to produce the contrary effect. I can only at present ex-
plain the cause of the difference thus : —

In a cement too rich in lime, a feeble portion of it remains in the state
of quicklime ; to this of course the addition of the carbonate of soda

426 FURTHBIt NOTKB ON INDIAN C EVENTS.

(the lime being stronger than the 6oda) gives the whole or a portion of
the carbonic acid to the quicklime, and therefore, transforming it into t
sub-carbonate of lime, quick setting.

I must, however, say that the whole question requires a good deal of
investigation, and I am at present making as many experiments on the
subject as possible, although I may already mention that a fat lime mixed
with 20 per cent, of carbonate of soda sets under water after six dtyi,
and that its hardness under water increases very sensibly, and keeps in-
creasing when left exposed to tair more than when the fat lime was used
by itself.

Margohi Cement. — As mentioned in my last quarterly report, I
have analysed and tested the new specimens of cement stones found in
the Margohi quarries.

Of five specimens discovered, one yields a very quick setting cement;
it exists in large beds. Another takes rather a long time in setting, viz.,
18 hours ; gets very hard afterwards, and will yield a very good material
either by itself or mixed with stones of other layers, giving a quicker
setting cement. This kind of stone is found in very extensive beds, d
thickness varying from three to six feet. This cement used pure obtain*
after 15 days a strength of 400 lbs. for an area of 1£" x 1£".

I must here notice that it has been found that if in a kiln loaded with
the materials used before which produced good magnesian cement, yoa re-
buin at a higher temperature, next to vitrification, all the stones, diffi-
cult to recognize from the others before burning, which have a greenish
color and are friable when burnt, you will obtain a kind of Portland
Cement, which when used pure, will break after two months under t
strength of 640 fee., and if mixed with one part of sand, will reach •
strength as high as 820 lbs.

It is thus remarkable that with all the cements obtained from the mag'
aesian calcareous and argillaceous beds of the Eymore Hills, a greater
strength is obtained when the cement is mixed with sand instead of
being used .pure. These cements are much more plastic than Portland
Cement, and consequently they are not affected by immediate immersion,
and have better binding properties than Portland Cement, which is
wanting in plasticity.

The more I consider the question of the cements obtained from the
strata of the Kyinore Hills, the more I feel convinced that they ought

FURTHER NOTES OK INDIAN CEMENTS. 427

to be extensively used in future hydraulic works of India, of course on
the distinct understanding that the quarries are worked on an extensive
scale under proper supervision.

Artificial Hydraulic Lime.— I reported in my quarterly report,
dated 4th November, 1874, on the advantages which will be derived from
the use, in Calcutta specially, of an artificial hydraulic lime made with
chalk and blue clay. I again beg to invite attention to the subject.

Numerous experiments since confirm the opinion therein expressed ;
and besides some lime of the above description was used by Mr. Mans-
field for plastering one side of Writers* Buildings close to similar work
(plastering), made with ordinary Sylhet lime nearly two years ago, and
the difference between the two may be observed ; though I should say that
while the plastering made with hydraulic lime is as hard as cement plas-
tering, the other is crumbling to pieces.

In fact, owing to dampness in Lower Bengal, hydraulic mortar only
ought to be used for plastering, as being more lasting.

P. D.

VOL. V. — SBC05D SEhlKS. •> I*

•

V .

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