CONTRACTS.
Clauses of Public Health Act -- Public contracts different from
private ones -- Specifications necessary -- Conclusion -- A list of
useful books 381
MUNICIPAL
AND
SANITARY ENGINEERS’
HANDBOOK.
CHAPTER I.
THE TOWN SURVEYOR.
The office of town surveyor was first legalised by the Towns Improvement
Clauses Act 1847 (10 & 11 Vic. c. 34, s. 7),[1] although for some
considerable period prior to this date similar appointments had been
made in several of the more important English towns, notably in the case
of Liverpool. In the following year the legal office of surveyor was
confirmed by the Public Health Act 1848 (11 & 12 Vic. c. 63, s. 37), and
it is now law under the Public Health Act 1875 (38 & 39 Vic. c. 55):
that comprehensive statute, under which all Sanitary Acts are now
included, and which Act will be frequently alluded to in the course of
this book.
The clause which specially refers to the appointment of the surveyor is
as follows:--
“Every urban authority shall from time to time appoint fit and proper
persons to be medical officer of health, surveyor, inspector of
nuisances, clerk, and treasurer: Provided that if any such authority is
empowered by any other Act in force within their district to appoint
any such officer, this enactment shall be deemed to be satisfied by the
employment under this Act of the officer so appointed, with such
additional remuneration as they think fit, and no second appointment
shall be made under this Act. Every urban authority shall also appoint
or employ such assistants, collectors, and other officers and servants
as may be necessary and proper for the efficient execution of this Act,
and may make regulations with respect to the duties and conduct of the
officers and servants so appointed or employed . . .” (38 & 39 Vic. c.
55, s. 189), and these officers (except the medical officer of health
and the inspector of nuisances, when any portion of their salary is paid
out of moneys voted by Parliament _to the powers of the Local Government
Board_), may be removed by the urban authority at their pleasure, which
was not the case when the appointment was first made in 1847.
Here it is necessary to state that for sanitary purposes England and
Wales are divided into two divisions--viz. urban sanitary districts and
rural sanitary districts, the former of these divisions being further
subdivided into boroughs, where the urban sanitary authority is the
mayor, aldermen, and burgesses acting by the council, and districts,
which are under the authority of improvement commissioners or local
boards; the rural sanitary districts are the areas of unions not
included in urban districts, and they are under the authority of the
guardians of the union.
It is my intention to deal more particularly with the duties of a
surveyor acting under an urban authority, but the following section of
the Public Health Act 1875 relates apparently to the appointment of a
surveyor to a rural authority, although no mention is made in this or
any other clause of the Act directly of such an officer by name, except
that amongst the definitions of the Public Health Act the following
appears:--
“‘Surveyor’ includes any person appointed by a rural authority to
perform any of the duties of surveyor under this Act” (38 & 39 Vic. c.
55, s. 4).
The clause I have above referred to is as follows:--
“Every rural authority shall from time to time appoint fit and proper
persons to be medical officer or officers of health and inspector or
inspectors of nuisances; they shall also appoint such assistants and
other officers and servants as may be necessary and proper for the
efficient execution of this Act . . .” (38 & 39 Vic. c. 55, s. 190).
The following clauses apply to officers of rural as well as urban
authorities:--
“The same person may be both surveyor and inspector of nuisances . . .”
(38 & 39 Vic. c. 55, s. 192).
“Officers or servants appointed or employed under this Act by the local
authority shall not in any wise be concerned or interested in any
bargain or contract made with such authority for any of the purposes of
this Act . . .” (38 & 39 Vic. c. 55, s. 193).
“Before any officer or servant of a local authority enters on any office
or employment under this Act by reason whereof he will or may be
entrusted with the custody or control of money, the local authority by
whom he is appointed shall take from him sufficient security for the
faithful execution of such office or employment and for duly accounting
for all moneys which may be entrusted to him by reason thereof” (38 & 39
Vic. c. 55, s. 194).
In addition to these clauses there are several regulating the receipt of
money by officers, but these should not affect the town surveyor.
Although in many places he has the onerous duty of paying workmen,
certifying tradesmen’s accounts, and other financial transactions, he
ought under no circumstances to have anything to do with the receipt of
money. Unfortunately, in some of the smaller towns the surveyor is also
employed as rate collector; but as this is evidently a very improper
proceeding, I shall not further allude to it in any manner.
It will be observed that in the foregoing clauses of the Public Health
Act the word “surveyor” is always used, and thus this is the legal title
of those holding such appointments. It is obvious, however, that,
although this title may have well suited the office up to the year 1847,
when it was made the legal title, the prodigious growth of municipal
work during the last 35 years has made it necessary that some change
should be made, and the title altered to that of “engineer,” or some
other similar suitable name. At the present time several different
meanings and occupations are attached to the word “surveyor,” as the
following list will show:--“land surveyor,” “district surveyor,” “county
surveyor,” “road surveyor,” “surveyor of taxes,” “surveyor of customs,”
“quantity surveyor,” “fire insurance surveyor,” “Lloyd’s surveyor,” and
a still more curious instance where an urban authority is itself dubbed
“surveyor of highways” by the 144th section of the Public Health Act
1875; and the title of town surveyor as now applied cannot but lead to
confusion and to perfectly erroneous impressions as to his work and
duties.
Dr. Ackland, in a paper read before the Association of Municipal and
Sanitary Engineers and Surveyors, at a district meeting held at Oxford,
makes the following remarks on this point:--“In the Public Health Act
1875 (the summary of all health enactments) the name of ‘engineer’ does
not once occur in the 343 clauses. He is still the old ‘surveyor’ we all
remember, the plodding, energetic man of highways and byeways . . . but
then the surveyor of the present day may be called on to advise on
anything, from the form and cost of an earthen syphon trap to the
calculation of work to be done by engines which are to supply half a
million of persons with water; to be responsible for the construction of
sanitary mechanisms, from a housemaid’s sink to an intermittent downward
filtration farm.”
There can be but little doubt that it is absolutely necessary for the
town surveyor of the present day to be a competent civil engineer of
great knowledge and varied experience, for he may at any moment be
called upon to advise his corporation upon any of the following
subjects, or to act in any one of the following capacities, in addition
to the multifarious ordinary duties legally devolving upon him as
surveyor under the Sanitary Acts:--
(1.) As engineer for sewerage and sewage works.
(2.) As engineer for water and gas works.
(3.) As engineer for canals, docks, harbour improvements, and river
navigation, or for the protection of coasts against the encroachments of
the sea, and the prevention of floods by rivers.
(4.) As engineer for the construction and maintenance of roads and
bridges.
(5.) As engineer for the construction and maintenance of lines of
tramways.
(6.) As architect for the construction of lunatic asylums, municipal
offices, hospitals, abattoirs, mortuaries, baths and wash-houses,
cemetery chapels, stables, police stations, and other similar works.
(7.) As landscape gardener for the laying out of public recreation
grounds, parks, and cemeteries.
(8.) As quantity surveyor to make estimates of all works, and often
(very improperly) to furnish bills of quantities to intending
contractors.
(9.) As surveyor and valuer to advise his employers on the values, &c.,
of corporate or other property.
(10.) As land surveyor to make surveys of any size that may be required.
(11.) As accountant to examine and rectify the workmen’s wages sheets,
and all tradesmen’s accounts for work performed or goods supplied.
The foregoing list is no exaggeration of the onerous duties of the town
surveyor, and it seems to be a grievous mistake that this officer, whose
importance in all practical sanitary work cannot be over-stated (as
without him no useful municipal work could go on) has been left
unprotected by the Public Health Act of 1875.
In that Act both the medical officer of health and the inspector of
nuisances have received Government protection, whereas the surveyor, the
very officer of all others who necessarily is more likely to come into
collision and to be unpopular with his employers in the faithful
discharge of his duties, has been afforded no protection whatever, but
has been left to the tender mercies of an annually changing body of
municipal governors, “to be removable at their pleasure” (38 & 39 Vic.,
c. 55, s. 189).
On this highly important point I cannot do better than quote several
passages from Mr. Lewis Angell’s interesting address to the Association
of Municipal and Sanitary Engineers and Surveyors on the occasion of
their inauguration in the year 1873:[2]
“The ‘town surveyor,’ according to his opportunities, has done the
country good service, but, surrounded as we have been with obstructions
and difficulties, cramped and restricted by popular prejudices and
private interest, subject to clamour and attack, without protection and
without appeal, it is indeed surprising that we have accomplished so
much. Had such officers been from the first judiciously selected,
adequately remunerated, properly supported, and duly protected, our
influence upon sanitary progress would have been more conspicuous and
our office better appreciated.
“As engineers we do not pretend to a knowledge of medical science, but
it is equally within the knowledge of the average sanitary engineer as
of a medical officer of health that pure air, pure water, properly
constructed houses, and an unpolluted soil are the cardinal conditions
of health. These are mere sanitary axioms. The means by which such
conditions are attained are drainage, ventilation, water-supply, and
other matters entirely within the functions of the engineer. It is the
function of the sanitary engineer to prevent that which the medical
officer of health is called upon to detect. . . .
“In many cases the unprotected surveyor may be required to report to a
protected medical officer the negligence of his own employers. No local
surveyor or engineer can be expected to give cordial and active
assistance in compulsory sanitary work when he is conscious that his
action would be opposed to the views or the interests of his employers,
the public upon whom he is dependent. The existence of such a
distinction between the medical officer and surveyor under the same
board will produce a want of harmony in interest, and must lead to a
divergence of action between the two departments. . . .”
And speaking of the multifarious duties of the town surveyor, Mr. Angell
says: “Any one section of his duties would, under commercial
circumstances, command fair pay according to its importance; but where
cumulative duties are included in the same office, they demand constant
attention, special knowledge, professional experience, and
administrative ability; to which is added the anxiety which the
responsibilities of public office always involve. Such a position in a
commercial concern would receive high remuneration in proportion to the
extent of the undertaking, but unfortunately, our work does not pay a
dividend: it is all expenditure from which the town derives no return
excepting in health and comfort, matters which are neither fairly
assessed, nor duly appreciated; consequently, the municipal engineer is
paid less for his professional knowledge than the contractor’s agent
whose work he directs.”
Speaking further on the subject of Government protection, Mr. Angell
says: “Surveyors appointed under the Towns Improvement Clauses Act were
protected during the existence of the General Board of Health. Sir C.
Adderley’s Public Health and Local Government Bill of 1872 proposed
similar protection. Officers employed under the Poor Laws are fully
protected as to position, emoluments, and superannuation. The
administration of the Poor Laws and the Public Health Acts is now united
in one department under the newly established Local Government Board: it
is therefore in my opinion equally due to Local Board officers, that
they also should be recognised and protected. Without such protection,
sanitary legislation cannot, in the words of the Royal Sanitary
Commission, be ‘active and effective,’ because local officers are too
dependent on their immediate employers to be thoroughly efficient.
“In advocating protection let me not be misunderstood. I do not mean
centralisation or the removal of that proper control which every local
authority should maintain over its own officers. I would maintain intact
the great principle of local government, which has been the bulwark of
our social and political freedom. But local government may degenerate,
and in small towns deteriorate into littleness: local affairs are too
frequently avoided by those who are most fitted by intelligence and
social standing to take part therein. I would simply control in the most
constitutional manner the short-comings or excesses of local government
as is already done in various other departments. I would require that
local officers should be properly qualified and adequately remunerated;
that in the honest discharge of their duties and during good behaviour
they should be protected from the effects of ignorance, narrow
prejudices, and interested clamour, and that they should have an appeal
to a disinterested and judicial body, superior to local feeling. The
demand is reasonable--I ask no more. . . . .”
To these admirable remarks by Mr. Angell on the present position of the
town surveyor I can add but little.
I believe that the sole reason which is given why Government protection
is not granted to the surveyor is the argument used by those in
authority, that if a surveyor disagrees with the corporation he serves,
it is considered better that he should resign his appointment rather
than be protected by the Local Government Board or other central office;
but if this argument is sound, why does it not also apply in a similar
manner to the medical officer of health or the inspector of nuisances?
The real fact no doubt is, that in framing the Public Health Act of
1875, medical men were consulted and not engineers, and this is very
apparent in many of the clauses, which will be fully considered in their
proper places in this book.
The time will no doubt come when the necessity for some change in the
position of the town surveyor will be apparent, and adequate protection
will be afforded him; in the meantime let him strive, by attention to
work, and by daily advancement in scientific knowledge, and in courtesy
to those with whom he is associated, to make the position and power of
the town surveyor felt and honoured as it should be throughout the
kingdom.
[1] The section is as follows:--“The Commissioners shall appoint,
subject to the prescribed approval, or where no approval is
prescribed, subject to approval by one of Her Majesty’s principal
Secretaries of State, a person duly qualified to act as a local
surveyor of the paving, drainage, and other works authorized under the
provisions of this and the special Act . . . . . . and the
Commissioners with the like approval may remove any such surveyor.”
[2] _Vide_ ‘Minutes of Proceedings of the Association of Municipal and
Sanitary Engineers and Surveyors,’ vol. i. p. 18.
CHAPTER II.
THE APPOINTMENT OF SURVEYOR.
Whenever a vacancy occurs in the office of surveyor to a town, or upon a
sanitary authority determining to make such an appointment, the question
is usually relegated to a committee or sub-committee to report upon the
subject, to fix the amount of salary proposed to be given, and frame the
duties of the office.
The following report is one that has lately emanated from an important
English borough, and is given in full as a specimen of such reports, and
as a guide on which a report could be framed; altered, of course, to
such requirements as may be locally necessary:--
_Report of the Special Sub-Committee as to the Surveyor._
(1.) Your sub-committee report that they have, in compliance with the
resolution of the day of , carefully considered the steps to be
taken with reference to the vacancy caused by Mr. ------’s resignation,
and they have come to the unanimous conclusion that it is desirable that
the office of surveyor should be continued.
(2.) Your sub-committee have also considered the duties which were
assigned to the office of Mr. ------’s appointment, and they beg now to
submit them, revised in accordance with the present circumstances of the
department, and with the recommendations contained in this report.
(3.) Your sub-committee further recommend that the salary of the
surveyor be fixed at £ . . per annum, and that advertisements be issued
for candidates.
_Duties of the Surveyor._
(1.) To have charge of the repairs of all highways, and to perform all
duties devolving on the council as surveyors of highways.
(2.) To report from time to time to the committee superintending the
same, the state of the several highways and lines of tramway, and as to
the materials wanted or works necessary.
(3.) To prepare all plans, specifications, or instructions necessary in
relation thereto, and as to the materials to be used therein, and to see
that all works are completed according to contracts entered into.
(4.) To engage and dismiss under sanction of the committee all workmen
employed at daily and weekly wages.[3]
(5.) To certify all accounts for work done, materials supplied, and
wages due.
(6.) To have charge of all materials and implements.
(7.) To purchase or contract for, or hire all horses, carts, tumbrils,
stones, flags, gravel, draining pipes, and proper implements and
materials, and all other matters and things, at such prices and in such
manner as the committee shall judge reasonable and expedient, and to
sell or otherwise dispose of the same as he may be directed.
(8.) To have the entire charge and superintendence of the breaking up
and repairing of all streets, for the purpose of laying or replacing gas
and water pipes.
(9.) To inspect and report, in conjunction with the medical officer of
health, upon slaughter-houses preliminary to licences being granted, and
to make the plans and superintend the construction of any
slaughter-houses which the council may hereafter erect.
(10.) To take all levels and surveys which may be necessary for the
purpose of deciding on the best mode of draining the several districts,
or any part thereof, or for the purpose of fixing the levels and
inclinations of any streets or roads, or in anywise relating thereto.
(11.) To carry out the scheme now in course of construction for the
interception of the sewage of the borough, and any future scheme, for
its precipitation, filtration, deodorization, or any other process which
the council may adopt, either within or without the borough.
(12.) To superintend the construction and completion of all tramway
lines and sidings which may be required.
(13.) To prepare, from time to time, schemes for the drainage of the
several districts or any part thereof.
(14.) To prepare all such plans, sections, and specifications as may be
necessary for the due execution of any flagging, paving, sewering, or
other works required to be done, or for entering into any contracts in
relation thereto, and to see that all works are executed in accordance
therewith.
(15.) To measure up and duly certify the execution of all works, and
apportion the cost to the parties chargeable therewith.
(16.) To see that all house drains, which may from time to time be
carried into any public sewer, are made and connected in accordance with
the regulations.
(17.) To give to the several contractors performing any works, orders
for the same in writing only, keeping duplicates thereof, duly entered
in a book to be kept by him for that purpose.
(18.) To prepare all plans, drawings, and estimates required, and to
superintend the execution of all improvements.
(19.) To see that no encroachments be made on any highway or public
place.
(20.) To advise on, and execute, all engineering works, and prepare all
such plans, specifications, and estimates of, and take out quantities
for, such sewers, buildings, bridges, and works as may be required, and
to superintend the erection and execution thereof.
(21.) To have in his charge, and be responsible for, the proper
management of all buildings and properties belonging to the corporation,
or for the repair and maintenance of which the corporation is liable,
except otherwise directed by the council.
(22.) To examine and report upon all plans and elevations of buildings
proposed to be erected or altered upon land sold or leased by the
corporation.
(23.) To inspect and report on plans of new streets to be laid out, of
houses to be built, and of buildings to be erected or altered.
(24) To see that all streets are properly named, and that the name
plates are kept in good order.
(25.) To act as building surveyor in all matters relating to the
execution of the Sanitary and Local Acts, and to examine and certify new
houses as fit for habitation.
(26.) To examine all buildings in a condition dangerous to the public,
to report thereon, and to take such steps as may be necessary to prevent
accidents arising therefrom.
(27.) To prepare all plans and sections for deposit, pursuant to
Standing Orders, with respect to all street improvements, tramways,
gasworks, waterworks, or other works, unless otherwise ordered by the
council, and to prepare all other surveys, plans, and sections required.
(28.) To attend the meetings of the several committees when required.
(29.) To prepare all returns relating to his office that may be required
by the Government.
(30.) To attend in London or elsewhere when required, without extra
charge, excepting only his travelling and hotel expenses.
(31.) To keep accurate permanent records and plans relating to all
properties purchased, leased, or sold, or in possession.
(32.) To devote the whole of his time to the duties of his office, and
not to be engaged in any other office, business, or employment
whatever.
(33.) To report from time to time all and every matter connected with
any branch of his office which, in his opinion, may require the
attention of any committee, and take their instructions thereon.
* * * * *
Clauses 18 and 20 in the above list of duties are very comprehensive,
and as a rule a town surveyor’s duties may be summed up in a very few
words--“to do anything that he is requested.” It is, however, better
that some definite instructions should be laid down, and those which I
have given may be taken as a fair specimen of what such duties may be.
Unlike the medical officer of health, who by Act of Parliament is
required to hold a diploma of competency,[4] it is open to anyone to
apply for and obtain the appointment of a town surveyor. This is no
doubt unfortunate, as some test of merit is desirable, and of late years
the necessity of some examination as to competency has been much
discussed.
In order to meet this requirement, the Sanitary Institute of Great
Britain has instituted examinations and granted certificates of
competency for both town surveyors and inspectors of nuisances. The
following particulars of these examinations, and the reasons given for
their necessity, may be of interest, and are given in full.[5]
_Examination of Local Surveyors and Inspectors of Nuisances._
The great and increasing importance of the duties devolving upon local
surveyors and inspectors of nuisances in connection with the various
statutes relating to Public Health and the Sale of Food and Drugs Act,
has led the council of the Institute to establish voluntary examinations
for local surveyors and inspectors of nuisances, and for persons
desirous of becoming such, or of obtaining the certificate of the
Institute.
Each examination occupies a portion of two days. On the first day the
examination of surveyors is continued for four hours, viz. from 2 to 4
and 6 to 8 P.M. and consists of written papers only. Inspectors of
nuisances have two hours’ written examination on the first day, viz.
from 4 to 6 P.M. On the second day the examination for both classes
commences at 11 A.M., and is _vivâ voce_; with one or more questions to
be answered in writing if deemed necessary. A certificate of competence
signed by the examiners is granted to successful candidates.
As rural sanitary authorities are able under the Public Health Act 1875
to obtain almost all the powers of urban sanitary authorities, it is not
considered advisable to make any distinction in the examination of the
two classes of surveyors.
As one person may, under the Public Health Act 1875, be both local
surveyor and inspector of nuisances, candidates wishing to obtain the
double qualification may enter for both examinations on the same
occasion.
Candidates are required to furnish to the council of the Institute
satisfactory testimonials as to personal character, and to give two
weeks’ notice to the secretary previous to presenting themselves for
examination, stating whether they wish to be examined as surveyors or
inspectors of nuisances, or as both.
The fee for the examination must be paid to the secretary, by
post-office order or otherwise, at least six days before the the day of
examination. On receipt of the fee a ticket will be forwarded admitting
to the examination.
The fees payable for the examination are as follows:--
For Surveyors £5 5 0
For Inspectors of Nuisances 2 2 0
Unsuccessful candidates are allowed to present themselves a second time
for one fee.
_Syllabus of Subjects for Examination for Local Surveyors._
_Laws and Bye-Laws._--A thorough knowledge of the Acts affecting
sanitary authorities, so far as they relate to the duties of local
surveyors; also of the model bye-laws issued by the Local Government
Board.
_Sewerage and Drainage._--The sanitary principles which should be
observed in the preparation of schemes for, and the construction of
sewerage works; the ventilating and flushing of sewers and drains; the
internal drainage and other sanitary arrangements of houses, privies,
water-closets, dry-closets, and the removal of refuse; the sanitary
details of builders’ and plumbers’ work.
_Water Supply of Towns and Houses._--The sanitary principles which
should be observed in the preparation of schemes for, and the
construction of water-works; the various ways in which water is likely
to become polluted and the best means of ensuring its purity.
_Regulations of Cellar Dwellings and Lodging Houses._--General
principles of ventilation; the amount of air and space necessary for men
and animals; the means of supplying air, and of ensuring its purity.
_Highways and Streets._--The sanitary principles which should be
observed in the construction and cleansing of streets and roads.
EXAMINATION PAPERS, NOVEMBER 6, 1879.
_Questions for Surveyors, November 6, 1879, 2 to 4 o’clock._
1. Define street; state the law applicable to every description of
street in an urban sanitary authority district, and the rights and
obligations and duties of sanitary authorities, owners and occupiers
therein.
2. What are the relative advantages of circular and egg-shaped sewers;
in what case are they respectively preferred?
3. Give a specification of a water-tight sewer. Describe and give a
sketch of the form of man-hole which you consider best adapted for
ordinary town sewers, and state the rule which you adopt for determining
the amount of ventilation to be afforded in a main street sewer.
4. In what way does the size and shape of the sewer affect the velocity
of sewage flowing through it? If a nine-inch pipe sewer, laid at an
inclination of 1 in 200, gives a velocity of 3 feet per second, what
velocity will it give when laid at an inclination of 1 in 800, the pipe
running full in each case? Will this velocity suffice to keep it clear
from deposits? Describe the various modes which may be resorted to for
flushing sewers.
5. Give a description of the process termed intermittent downward
filtration. State what area of land you would require, with a gravelly
soil, for applying this method of purifying sewage to a town with a
population of 1000 inhabitants, and state the arrangements you would
adopt for dealing with the rain-water falling on the roofs, yards, and
streets.
_November 6, 1879, 6 to 8 o’clock._
1. In reporting upon the source of water supply for a town, what are the
points to which you would direct your attention?
2. Give a sketch of a ~D~ trap, an ~S~ trap, a ~P~ trap, and a pan water
closet (plan of a dwelling-house annexed).
3. Criticise the arrangements of this residence as to position of rooms,
walls, doors, fire places, windows, &c., from a sanitary point of view.
4. Describe the drainage arrangements shown on the plan. Say whether
they are satisfactory; if not, in what way are they faulty?
5. Sketch on the plan any other system of drains which you would think
preferable.
6. Describe in detail the arrangements necessary for the water supply
of the residence, a bath being fixed in the room over the serving room,
a W.C. on the first floor over that on the ground floor, and a
housemaid’s sink near.
* * * * *
It is, of course, open to consideration whether the Sanitary Institute
of Great Britain is the proper authority to hold these examinations or
not; but there is no doubt that some such examination is necessary, and
would be welcomed by nearly all town surveyors in order to more firmly
secure their positions; and the Sanitary Institute is entitled to every
credit for having taken the initiative step in the matter.
Under the present system of appointment to the office of town surveyor
those seeking that office must be prepared to work hard to obtain it,
and to give up some considerable time to its acquisition. Tact,
patience, and perseverance are indispensable qualities when seeking such
appointments, and the following suggestions on this matter may be of
use.
The appointment usually rests finally with the whole body of the town
council or corporation, even if a sub-committee or committee has been
appointed in the first case to make some selection of candidates. The
candidates thus selected by the committee are usually requested to
appear before the whole body of the town council, who then make the
appointment from amongst them.
The first thing a candidate should do when he hears of a vacancy
occurring in the office of a town surveyor, or sees an advertisement
requiring a surveyor’s services, is to obtain fresh testimonials from
those persons of position and influence for whom he has worked or who
know him professionally. These testimonials, with any very good old ones
(but not too many of either), should be sent by post to the town clerk
or person mentioned in the advertisement, with a formal,
carefully-worded application for the appointment.
If canvassing is not prohibited, a list of the members of the town
council, with their addresses, should then be procured, to whom printed
copies of the application and testimonials should be sent, accompanied
by an autograph letter asking that the application and testimonials
should be read.
This should be followed up (if possible, immediately), by a journey to
the town and a personal visit to each member of the council or
corporation, not necessarily for the purpose of soliciting a vote, but
with a view to making the acquaintance of the members of the corporation
and to identify the applicant with his testimonials; and in these visits
great tact and patience are necessary. It is also of importance to seek
and obtain all the outside influence that is possible, in order to bear
upon the members of the corporation, by means of letters of
introduction, and informal testimonials as to eligibility for the
appointment, and personal character and position, &c.
Canvassing on behalf of oneself is extremely unpleasant and harrassing
work; but wrong as the system may appear to be, it is not easy to see
how, in municipal government, any other method can be adopted, and the
visit of the candidate to each member gives the latter an opportunity of
asking him questions and satisfying himself as to his qualifications,
and thus he will not feel he is acting blindly when he gives his vote in
favour of that candidate whom he thinks, after a personal interview, the
most suitable for the appointment.
[3] This seems to be an undue interference with the control which a
surveyor should always have over his men.
[4] “A person shall not be appointed Medical Officer of Health under
this Act unless he is a legally qualified medical practitioner” (38 &
39 Vic. c. 55, sec. 191).
[5] _Vide_ ‘Calendar of the Sanitary Institution of Great Britain for
the year 1880.’
CHAPTER III.
THE SURVEYOR’S DUTIES.
It will be observed on reference to the list of the duties of the
surveyor, given in the preceding chapter, that the first on the list is
as follows:--
“To have charge of the repairs of all highways, and to perform all
duties devolving on the council as surveyors of highways.”
The necessity for these duties are obvious when we turn to the Public
Health Act 1875, and read the following sections:--[6]
“Every urban authority shall within their district, exclusively of any
other person, execute the office of and be surveyor of highways, and
have, exercise, and be subject to all the powers, authorities, duties,
and liabilities of surveyors of highways under the law for the time
being in force, save so far as such powers, authorities, or duties are
or may be inconsistent with the provisions of this Act; every urban
authority shall also have, exercise, and be subject to all the powers,
authorities, duties, and liabilities which by the Highway Act 1835, or
any Act amending the same, are vested in and given to the inhabitants in
vestry assembled of any parish within their district.
“All ministerial acts required by any Act of Parliament to be done by or
to the surveyor of highways may be done by or to the surveyor of the
urban authority, or by or to such other person as they may appoint” (38
& 39 Vic. c. 55, s. 144).
“All streets being or which at any time become highways repairable by
the inhabitants at large within any urban district, and the pavements,
stones, and other materials thereof, and all buildings, implements, and
other things provided for the purposes thereof, shall vest in and be
under the control of the urban authority. The urban authority shall from
time to time cause all such streets to be levelled, paved, metalled,
flagged, channelled, altered, and repaired as occasion may require; they
may from time to time cause the soil of any such street to be raised,
lowered, or altered as they may think fit, and may place and may keep in
repair fences and posts for the safety of foot-passengers. Any person
who without the consent of the urban authority wilfully displaces, or
takes up, or who injures the pavement, stones, material, fences, or
posts of, or the trees in, any such street shall be liable to a penalty
not exceeding five pounds, and to a further penalty not exceeding five
shillings for every square foot of pavement, stones, or other materials
so displaced, taken up, or injured; he shall also be liable, in the case
of any injury to trees, to pay to the local authority such amount of
compensation as the court may award” (38 & 39 Vic. c. 55, s. 149).
The duties thus devolving upon the town surveyor by reason of these
sections and the orders of the council are very considerable. The
following table gives a list of the principal subjects which will
require his attention; all of which will be considered in due course in
this book.
_List of Duties devolving upon a Town Surveyor as “Surveyor of
Highways.”_
(1.) The construction and maintenance of highways or streets,
including--
(_a._) Roads formed of broken stones or “metal,” commonly called
macadamised roadways;
(_b._) Streets paved with granite cubes or setts;
(_c._) Streets paved with wood;
(_d._) Streets paved with asphalte.
(2.) The construction and maintenance of footwalks or footpaths,
including the different materials of which these are formed.
(3.) The breaking of stone for road metal.
(4.) Steam rolling.
(5.) The necessary notices and specifications under the 150th Section of
the Public Health Act 1875, for the purpose of compelling private
streets to be properly sewered, levelled, paved, metalled, flagged,
channelled, lighted, and made good.
(6.) The lighting, cleansing, and watering of streets.
(7.) The naming and numbering of streets.
(8.) The planting of trees along the sides of footwalks.
(9.) Obstructions caused by builders’ rubbish or by hoardings and
scaffold poles; and also by dangerous or defective cellar coverings.
(10.) The damage caused to footpaths by allowing water from private
premises to flow over them, and the nuisance caused by defective
rain-water gutters or shutes.
(11.) The damage caused to roadways by the laying or removal of gas and
water mains and services, and the surveyor’s powers and duties in
connection therewith.
(12.) The importance, especially in old towns, of laying down improved
building lines of frontage in the narrower or crooked streets.
(13.) The examination of all plans of proposed new streets or buildings.
(14.) The supervision of all new streets and buildings whilst their
construction is in progress.
(15.) Dealing with all buildings in a condition dangerous to the public.
Each of the foregoing list of duties will be dealt with in separate
chapters in addition to other matters which will be treated, but before
closing this chapter a few words upon the subject of “meetings” may be
of use.
It will be observed upon reference to the list which I have given of
the duties of the surveyor, that there is one which says, “To attend all
meetings of the board, and committee meetings, except where his
attendance has been previously dispensed with; to attend upon the
chairman when so required.”
The result of this order is that a very large percentage of the
surveyor’s time has to be devoted to attendances at long meetings of the
Board or town council, and at the numerous committee and sub-committee
meetings which are appointed under it.
This work is doubled where, as in some towns, the corporation and their
committees sit in a dual capacity, viz. as the council proper, and the
council as the urban sanitary authority; this generally involves two
ordinary meetings of the whole body each month, and probably at least
six committee meetings a week, leaving the surveyor but scanty time to
look properly after his works.
With regard to these committee meetings it is necessary that each should
have some distinguishing title descriptive of the class of work over
which it has jurisdiction, and in selecting names for them the following
list may be of some service:--Finance Committee, General Purposes
Committee, Law and Parliamentary Committee, Surveyor’s Committee, Land
and Estates Committee, Rates and Taxes Committee, Streets Committee,
Lighting and Cleansing Committee, Navigation of Port Committee, Public
Grounds Committee, Sanitary Committee, Drainage and Sewerage Committee,
Markets Committee, Properties for Sale Committee, Works Committee, Water
Committee, Gas Committee, Watch Committee, Health Committee, Library
Museum and Arts Committee, Baths Committee, Parks, Gardens, and
Improvement Committee, Streets Improvement Committee, etc. etc.
The surveyor should always endeavour to be punctual in his attendance at
the council meetings and those of the committees, as to be late is
always looked upon with disfavour. His reports should as much as
possible be in writing, so that there should be no misunderstanding as
to what his advice is on any subject. To save trouble and expense it is
well that all drawings of new schemes should be first submitted to a
committee in pencil, as they are frequently much altered; this is very
vexing if they have been neatly and highly finished. It must not be
forgotten that the gentlemen who form municipal bodies give their time
gratuitously, and everything should be done to save it as much as
possible. It is an excellent plan and a great convenience, if a surveyor
will have a series of named and numbered pigeon holes in his office
corresponding to his committees, in which to place all papers, drawings,
correspondence etc., which he intends to bring up to the next meeting of
a committee; thus saving himself flurry at the last moment before the
meeting, in endeavouring to find the papers he wants. With his varied
duties, correspondence, interviews, meetings, inspections,
investigations, reports, drawings, and calculations, the motto of a
surveyor’s office should be “method.”
[6] For full particulars and explanations of the various Highway Acts
see ‘The Powers and Duties of Surveyors of Highways and of other
Authorities with regard to the Management of the Public Highways,’ by
Alex. Glen, M.A., etc.
CHAPTER IV.
TRAFFIC.
Before a surveyor can decide upon the best material with which the
streets of his town shall be paved, it will be well to consider the
question of the class of traffic they will have to bear.
It must be remembered that three distinct interests have to be
considered in dealing with this question, viz. (1.) The rate-payers,
upon whom the cost of construction and maintenance of streets falls.
(2.) The owners and employers of horses and vehicles who principally use
the streets; and (3.) The inhabitants of the adjoining premises, who
would be annoyed if the material selected were unduly noisy or dirty. In
addition to these considerations, much depends upon local circumstances;
the class of trade upon which the welfare of a town is dependent must
not be lost sight of. A pavement suitable for a busy, pushing
manufacturing city may not be suitable for a quiet agricultural or
cathedral town, or for a town which is used as a health resort. Again,
the question of the most adaptable materials must be considered, and the
climate and physical character of a town should enter largely also into
this question.
To condense the requirements of a good roadway into as small a compass
as possible, the following may be given as some of its principal
requisites:--
(1.) It must not be extravagantly costly in its first construction.
(2.) It must be durable and require the least possible amount of repairs
at the least cost.
(3.) It must be safe, firm and hard, with an even face and yet giving
sufficient foothold to horses.
(4.) It must be as noiseless as possible.
(5.) It must be so constructed as to be quickly laid down and repaired
when broken up for water, gas, drains, or other purposes.
(6.) It must be of strong foundation, so as to carry the heaviest weight
without subsidence.
(7.) It must be of such a shape as will throw off all surface water at
once.
(8.) It must be of such materials as will make a minimum of dust or mud.
(9.) It must be easily cleansed.
(10.) It must be non-absorbent of impurities or moisture of any kind.
(11.) It must give easy traction upon its surface.
(12.) It must not cause jolting to the traffic.
(13.) It must not injure horses’ legs or hoofs.
Of the above requirements No. 1 affects the ratepayers alone; Nos. 3,
11, 12, 13, affect the traffic only, except that the occupiers of shops
are indirectly affected by them; No. 4 affects both traffic and
occupiers, and No. 10 affects the occupiers principally. The remainder
of the requirements affect all three interests.
With reference to the wearing effect of traffic upon the surface of the
roadway, no standard has yet been arrived at by which this can be
determined with accuracy. In France a great number of observations and
experiments have been made from time to time by the engineers of the
Ponts et Chaussées, but their practice has been to count the number of
“collars” passing a given section of a roadway in a given time,
irrespective of the weights, speeds, or number of wheels such collars
may be drawing. Mr. Deacon, the former Borough Engineer of Liverpool,
has, however, reduced traffic to a standard of tons per yard width of
roadway per annum. This he effected by having the traffic in any street
carefully watched for a certain definite time, the number of vehicles,
their character and approximate weight being noted as well as the number
of horses by which they were drawn, and their number of wheels.
The effect of the traffic thus tabulated, arranged, and reduced to ton
yards per annum, can be ascertained upon any roadway, and Mr. Deacon has
given the results of his observations in a valuable paper on the subject
of street carriage pavements which he read before the Institution of
Civil Engineers.[7]
Sir John MacNeill has estimated that 80 per cent. of the total wear of a
road is due to traffic, the remaining 20 per cent. being due to
atmospheric causes. Of this 80 per cent. 60 per cent. he considers is
due to the action of horses’ hoofs where the traffic is fast, and 44·5
per cent. where the traffic is slow. General Morin estimates the wear of
a road due to horses’ feet to be two-thirds of all causes. There can be
no doubt that the action of horses’ feet, shod as they are with heavy
iron shoes with long toe pieces and heels, must have a destructive
effect upon the surface of a carriage-way, and this may be easily
observed when watching the ruts formed by any continuous line of traffic
in a roadway.
The following remarks from a report of the Society of Arts on this
subject may here be of interest. “It may be mentioned that as respects
the horses’ shoes, attention has long been called to its defects by Sir
Francis Head and others, but Sir Joseph Whitworth now points out the
achievement of a decided and important improvement, which will have a
large effect in road conservancy, as well as the reduction of noise. The
improvement consists in the fastening of a rim of hardened steel, of
about half-an-inch square, to the horses’ feet, and letting the frog
grow to its natural size. One effect is to reduce by five-sixths the
weight of the old shoe, or in other words to reduce by five-sixths the
weight of the iron hammers constituted by the common horses’ shoes,
pounding the road surface, and creating road dust and dirt, and
distributing it about. The saving in this respect, as well as the
reduction of noise by the reduction of the weight of rim, and also the
saving of road wear, would warrant the imposition of the stimulus of a
tax, or a toll upon heavy horses’ shoes to hasten this removal.”[8]
Up to the present date, however (1883), no general change has been
effected in the manner of shoeing horses, notwithstanding these
admirable remarks of Sir Joseph Whitworth upon the subject.
With reference to the question of traction upon roads General Morin, in
his ‘Expériences sur le Tirage des Voitures,’ states that the resistance
to the rolling of vehicles upon solid metalled roads and pavements is
proportional to the weight and inversely proportional to the diameter of
the wheels. On solid roads he states that the resistance is nearly
independent of the width of the tires when they exceed 3 or 4 inches,
but on a compressible face it decreases in proportion to the width of
the tire; the resistance further increases with the velocity on hard
roads, but does not do so when they are soft.
The following table is almost universally now adopted as showing the
traction upon level roads formed of different materials, asphalte being
taken as the standard of excellence in this respect.
Asphalted roadway 1·0
Paved roadway, dry and in good order 1·5 to 2·0
„ „ in fair order 2·0 „ 2·5
„ „ but covered with mud 2·0 „ 2·7
Macadamised roadway, dry and in good order 2·5 „ 3·0
„ „ in a wet state 3·3
„ „ in fair order 4·5
„ „ but covered with mud 5·5
„ „ with the stones loose 5·0 „ 8·2
There are four forces constantly at work tending to destroy the momentum
of vehicles passing along a roadway: they are gravity, collision,
friction, and the resistance of the air.
The first of these is lessened by easy gradients in a road, the second
can be overcome to a great extent by evenness of surface, the third by
hardness, and the fourth, as well as all the others, by giving
sufficient foothold to the animal drawing the vehicle.
Another excellent table[9] prepared from experiments made by Mr. Amos on
different descriptions of pavement in the City of London may be useful,
and is here given:--
-------------------+---------+-------+--------+--------------
| Speed | | |Tractive Force
Road Material. |in Miles |Draught|Fraction| in Decimals
|per hour.|in lbs.|of Load.| of the Load.
-------------------+---------+-------+--------+--------------
Gravelly Macadam in| 6·945 |126·6 | 1/45·3 | ·0219
a side street | 3·45 |114·322| 1/50·3 | ·0197
| | | |
| 5·15 | 70·963| 1/81·1 | ·0123
Granite pitching by| 3·196 | 41·932| 1/137·3| ·0072
side of tramway | 2·557 | 47·572| 1/121 | ·0082
| | | |
Granite Macadam | 4·239 |262·886| 1/21·9 | ·0456
“freshly laid” | 2·775 |242·726| 1/23·7 | ·0421
| | | |
| 5·025 | 91·525| 1/64·9 | ·0158
Asphalte Pavement | 3·56 | 69·753| 1/82·5 | ·0121
| 5·687 | 84·268| 1/68·3 | ·0111
| | | |
| 3·932 |118·163| 1/48·7 | ·0205
Wood Pavement | 3·278 |102·412| 1/56·2 | ·0177
| 3·827 |100·066| 1/57·5 | ·0173
| | | |
Macadam road, very | | | |
good on Victoria | 6·65 |109·06 | 1/52·7 | ·0181
Embankment | | | |
-------------------+---------+-------+--------+--------------
The following table from Law’s ‘Rudimentary Treatise on Civil
Engineering’ shows the force required to move a load of a ton weight on
different descriptions of roadway, the limiting angle of resistance, and
the greatest inclination which should be given to the road being also
stated.
--------------------------------+--------+-----------+------------
| Force | | Greatest
| in lbs.| Limiting |inclination
Description of the Road. |required| angle |which should
| to move| of | be given
| a ton. |resistance.|to the road.
--------------------------------+--------+-----------+------------
| | ° ′ |
Well laid pavement | 33 | 0 50 | 1 in 68
| | |
Broken stone surface on a bottom| 46 | 1 11 | 1 „ 49
of rough pavement or concrete | | |
| | |
Broken stone surface laid on an | 65 | 1 40 | 1 „ 34
old flint road | | |
| | |
Gravel road | 147 | 3 45 | 1 „ 15
--------------------------------+--------+-----------+------------
As a matter of fact, however, the gradient of a macadamised road should
not, if possible, exceed 1 in 20,[10] experience having shown that a
horse, unless the hill is a very long one, is able to draw his ordinary
load for a level up such an inclination, whereas, if it is steeper he is
sometimes stopped altogether, even though the carter tries the zigzag
route so as to obtain an artificial ease of gradient.
The table given in ‘Molesworth’ upon the same subject is too well known
to be repeated, and another table may be found in Sir Henry Parnell’s
work on roads, which gives a comparison between the draught necessary on
a well-paved road at 2, on a well-made, clean macadamised road at 5,
whereas on a wet and muddy gravel or flint road it rises to 32!
Mr. T. D. Hope, of Liverpool, assuming the power of traction at 100,
gives the following table:--
Weight drawn.
Level macadamised road 27 cwt.
„ granite pavement 30·5 „
„ wood „ 54·75 „
And Lieut. Crompton has given the resistance of wheels in lbs. per ton
on different surfaces as follows:--
Very good pavement 35 lbs.
Good macadam 60 „
Ordinary ditto 90 „
Newly-laid gravel 200 „
Soft grass land 300 „
Newly-laid metal 440 „
Here “newly-laid metal” comes out very badly, and points to the
necessity of rolling, of which I shall speak in a future chapter.
Whilst on the question of wheel resistance, it may be well to note that
the small front wheels of a waggon cause considerably more harm to a
macadamised road than the larger hind wheels. In the smaller diameter
any loose stone or obstruction is pushed along in front for a
considerable distance, often tearing up the surface of the road, whereas
in the other case the stone is forced into its place or crushed as under
a roller.
On the question of “safety” to traffic, Mr. Haywood, the eminent
Surveyor of the City of London, has caused several most complete
observations to be made from time to time, the results of such
observations being detailed by him in various reports. Amongst other
useful information compiled by him, he has ascertained that a horse will
travel 446 miles upon a roadway paved with blocks of wood without a
fall, 191 miles upon asphalte, and 132 miles upon granite setts. I
cannot do better than give verbatim his remarks upon this point:--
“Slight rain makes both asphalte and wood more slippery than they are at
other times. On asphalte the slipperiness begins almost immediately the
rain commences, wood requires more rain before its worst condition
ensues. The slipperiness lasts longer upon wood, on account of its
absorbent nature, than it does upon the asphalte; when dry weather comes
after the rain, when asphalte is in its most slippery state, and the
horses fall on it very suddenly, _on wood their efforts to save
themselves are more effectual_; wood also is frequently in that peculiar
condition of surface in which horses slip or glide along it without
falling. A small quantity of dirt upon asphalte makes it very slippery,
wood requires a large quantity. Slipperiness can be temporarily cured on
both pavements; on the asphalte by sprinkling it with sand, on the wood
by sprinkling it with gravel. The result in both cases is dirt. _The
sand thrown on asphalte helps to wear it out, the gravel thrown on wood
tends to preserve it._ When a horse falls on asphalte it has difficulty
in getting up; on wood it rises more readily.”[11]
In streets crowded with traffic, the constant stopping and starting,
especially on any surface that is slippery, is very trying to horses.
Attention has lately been directed to this point with a view to the
storage of some power in a vehicle, either by the compression of a
spring in stopping or by some other mechanical means, in order that in
starting the driver may at will liberate this power so as to assist the
horse in overcoming the inertia of his load. These trials, however, have
not at present met with much success.
Before closing this chapter on traffic, it will be well to point out
that nearly all vehicles travelling rapidly can pass each other safely
if allowed a clear space of eight feet; hence all roadways should, if
possible, be made of a width between the kerbs of some multiple of
eight: a convenient width for the footpaths, so far as foot-passenger
traffic is concerned, is found to be one-fifth of the entire width of
street. It is scarcely necessary to add that vehicles pass each other
on the left side, pedestrians on the right. It is not easy to assign a
cause for the former beyond custom, except that the whip is held in the
right hand, and in consequence free play is given for its use as the
driver sits on that side and can watch his wheels in passing. In France
and other countries the right side is the “rule of the road.” In the
case of pedestrians it is perhaps more convenient for many reasons to
pass on the right side, one being that the umbrella or parasol is always
carried in the right hand, which is also used to remove the hat when
bowing, and another because one’s tendency in passing any obstacle is to
give way with the left shoulder. For regulating the traffic and for the
protection of foot passengers, “sanctuaries,” as they are termed, have
often to be constructed by surveyors in broad streets or awkward centres
of traffic, and it is well to place a lamp-post on these sanctuaries, on
which may be advantageously fixed a notice, “Keep to the Left,” so as to
regulate vehicular traffic. On the lamp-posts at the edge of the
footpaths it is also sometimes customary to fix small enamelled iron
plates bearing the inscription on both sides, “Keep to the Right,” so as
to regulate the pedestrian traffic.
Of the danger to life and limb to pedestrians in London much has
frequently been said, and no wonder, when we consider the number of
persons who are daily injured and sometimes killed according to the
Registrar-General’s returns. Some years ago it was proposed to erect
light iron bridges over the most dangerous crossings approached by
winding stairs, but “time is money” in the mighty metropolis, and the
scheme was abandoned because it was felt that most persons would prefer
the risk of being run over rather than spend the time in ascending and
descending the necessary steps for this purpose.
[7] _Vide_ ‘Minutes of Proceedings of the Institution of Civil
Engineers,’ vol. lviii.
[8] _Vide_ Report of the Society of Arts on the application of Science
and Art to street paving and street cleansing of the metropolis, 1875.
[9] Ibid.
[10] Experiments made by the direction of the French Government on the
tramway between Sèvres and Versailles, showed that a horse on a level
tramway draws three-and-a-half times the weight, at the same speed and
with the same expenditure of power, that he can do on an ordinary
road. Up a gradient of 1 to 100, he is capable of drawing 2·25 times
the weight he can do up the same gradient on an ordinary road, and up
a gradient of 1 to 25 he can draw one-and-a-half times the load he can
do under similar circumstances on the ordinary road.
[11] ‘Report on accidents to Horses on Carriageway Pavements,’ by
William Haywood (1874).
CHAPTER V.
MACADAMISED ROADWAYS.
I do not propose in this work to speak of any of the engineering
operations necessary to lay out or construct long lines of connecting
roadways, as that is a duty which seldom falls to a town surveyor to
perform, and there are a great number of treatises and books upon the
subject already published. The object of this chapter will be to give
some information and hints upon the construction and maintenance of what
are known as macadamised roads, suitable for urban and suburban traffic.
There can be little doubt that roadways of this description are
expensive luxuries where the cost of their maintenance, owing to
excessive traffic or other causes, exceeds 2_s._ per square yard per
annum, but they are often necessary luxuries when the requirements of
the locality are considered, a point to which I drew attention in the
preceding chapter upon “Traffic.” For purposes of what may be styled
“pleasure traffic,” macadamised roadways are unequalled when well
constructed and maintained, but there are many objections to them which
will be considered in their place in this chapter.
The word macadamised is, as is well known, derived from one John Loudon
Macadam, who in the year 1816 first took up the question of putting
broken metal upon a road instead of the boulders previously used.[12]
His name, being rather a peculiar one, has been attached to this
description of road ever since.
As a matter of fact, the “macadamised” roadways of the present day are
constructed after a method introduced by Thomas Telford as an
improvement upon Macadam’s principles, and a perusal of the two
following specifications will, I think, show that there is not very much
difference between the method introduced by Telford and that followed at
the present time.
_Specification of a Roadway as designed by Thomas Telford more than
fifty years ago._[13]
“Upon the level bed prepared for the road materials, a bottom course or
layer of stones is to be set by hand in form of a close, firm pavement;
the stones set in the middle of the road are to be seven inches in
depth; at nine feet from the centre five inches; at twelve feet from the
centre four inches; and at fifteen feet three inches. They are to be set
on their broadest edges lengthwise across the road, and the breadth of
the upper edge is not to exceed four inches in any case. All the
irregularities of the upper part of the said pavement are to be broken
off by the hammer, and all the interstices to be filled with stone chips
firmly wedged or packed by hand with a light hammer, so that when the
whole pavement is finished there shall be a convexity of four inches in
the breadth of fifteen feet from the centre.[14]
“The middle eighteen feet of pavement is to be coated with hard stones
to the depth of six inches. Four of these six inches to be first put on
and worked in by carriages and horses; care being taken to rake in the
ruts until the surface becomes firm and consolidated, after which the
remaining two inches are to be put on.
“The whole of this stone is to be broken into pieces, as nearly cubical
as possible, so that the largest piece in its longest dimensions may
pass through a ring of two and a half inches inside diameter.
“The paved spaces on each side of the eighteen middle feet are to be
coated with broken stones or well-cleaned stony gravel up to the foot
path or other boundary of the road, so as to make the whole convexity of
the road six inches from the centre to the sides of it, and the whole of
the materials are to be covered with a binding of an inch and a half of
good gravel free from clay or earth.”
If the above specification, written more than fifty years ago, is
compared with one of the present date, it will be seen that there is a
strong resemblance between them.
_Specification of a Roadway as now executed._
The cross section of the roadway _when finished_ is to be an arc of a
circle, with a rise of 1 in 27 from kerb to the centre of the roadway
each way.[15] The roadway, when consolidated and finished, to be 12
inches in depth at the gutters and 15 inches at the centre, diminishing
gradually from this point right and left to the depth named. The gutters
to be 2 feet in width, formed of stone setts 6 inches by 6 inches, and
laid in sand, on a firmly consolidated surface of small broken stone or
gravel.
The earth road-bed on which the surface formation is to rest is to be
excavated to the required depth, and when graded and shaped to its
proper form, it is to be thoroughly and repeatedly rolled with a steam
roller, and all depressions which then appear are to be filled with the
same material as the road-bed, and rolled until the whole be uniformly
compact and firm.
On the road-bed thus formed and compacted, a bottom layer of stone of a
depth of 8 inches at the centre of the road, and gradually diminishing
to 6 inches at the kerb, is to be set by hand, to form a close, firm
pavement. The stones are to be laid, with their largest side down, in
parallel lines across the street, breaking joint as much as
practicable.[16] The width of the upper part of the stone not to be more
than 8 inches, nor less than 6 inches. The stone not to exceed 15 inches
in length. After being set closely together, the stones are to be firmly
wedged by inserting a bar in all possible places, and placing between
them stones as nearly as possible of the depth of the pavement, until
the whole is bound in position. Projections of the upper part of this
course are to be broken off, care being taken not to loosen the
pavement; and no wedging is to be done within 20 feet of the face of the
work being laid. The small interstices are to be filled in with stone
chips firmly wedged with hammers. The whole is to be thoroughly rammed
and settled to place, and all undue irregularities of surface broken
off.
On the foundation course must be laid an intermediate layer of broken
stones, varying in size from 3 inches in their greatest diameters to 1
inch in their smallest diameters. These irregular-sized stones may be
either the “tailings” of the screened stones, or may be raked from the
quarry, and placed on the roadway without being machine-broken; but they
must nevertheless be so laid as to compact solidly, and must be clean
broken stone, free from dust and dirt, and within the dimensions given
above. This intermediate course must be 4 inches in depth at the centre
of the roadway, gradually decreasing to 3 inches in depth at the
gutters; it is to be thoroughly rolled with the steam roller until it be
firm, compact, and solid. On its upper surface it must be identical in
rise and form to the cross-section of the finished pavement, as
specified above. In the laying of this course of stone a small quantity
of binding material is to be used, sufficient only to fill up the
crevices, and render this portion of the pavement solid. Preferably the
binding is to be of fine screened gravel or sand, which is to be
sufficiently watered during the process of rolling, so that the “licking
up” of the road material, and its adherence to the rolling-wheels may be
prevented.
On the intermediate course is to be laid the surface layer of broken
stone.[17] It must be 2¹⁄₂ inches in depth, and the stones must be
practically uniform in quality, and as near an approach to a cube in
form as possible. Each stone used in this layer must have passed through
a 2¹⁄₂-inch circular hole, and all stones that are wedge-shaped, and do
not approach uniformity of measurement on their sides, are to be taken
from the road with properly shaped rakes, and no stones allowed to
remain which are not sound, strong, and equable in size and quality of
material. The stones are to be raked into an even layer, and the steam
roller passed over them twice or thrice. After this a quantity of fine
screened gravel or sand is to be thrown on and sufficiently sprinkled to
moisten the mass without “licking up.” The rolling is then to be
continued (working the roller backwards and forwards, gradually from the
gutter to the crown), with an occasional light watering of the pavement,
until the cross-section be exact according to specification, the
interstices filled in, the roadway firmly compacted and solid, and all
excess of binding removed from the surface of the finished pavement.[18]
Telford’s object was the complete separation of the road metal from the
subsoil by a firm and regular foundation, and this system has ever since
held its ground. The advantages to be gained in constructing a roadway
in this manner may be summed up as follows:--
(1.) Economy of construction, as a considerable quantity of metalling is
saved; only 3 inches of properly broken stone and a little binding
material being necessary, the foundation of the roadway (which really
carries the traffic) may be made of a quality of stone unsuitable for
road metal, or even of bricks or stones from old buildings that are
being pulled down.
(2.) The prevention of the rising up or “spewing” of the clay or other
soft material on which the roadway rests.
(3.) A solid foundation is secured which will successfully resist the
weight and percussion of the traffic.
(4.) The increased facility for the drainage of the roadway water being
ruinous to it.[19]
Instead of forming a paved or “pinned” foundation for macadamised
roadways, sometimes what is called “hard core” is placed at the bottom
of the road upon the surface formation.
This “hard core” is made of very heterogenous materials, often the waste
products of the house refuse depôt, and consists of ashes, old pots and
pans, meat tins, old bottles, shells, and a variety of similar articles;
sometimes the core is made of burnt ballast, but in no case does it make
so good a foundation as stones set by hand.
Concrete has also been employed as a foundation with great success, but
it is very expensive, and is seldom used except under streets paved with
either granite, wood, or asphalte, of which I shall speak hereafter; for
if the traffic was so great as to necessitate the use of concrete for a
foundation it would surely be better to give the roadway a more durable
surface than macadam.
The following tables, showing the thickness of the foundation and
metalling of broken stone roads, is from a paper on roadways, read to
the Association of Municipal and Sanitary Engineers, by Mr. James Hall,
Borough Surveyor of Stockton, and may be of use to those who would like
to know what proportions to use.
-------------+-------------------------+---------------+------------
| Pinned Foundations. | Broken Stones.| Concrete.
+--------+---------+------+-------+-------+-----+------
|Pinning.|Covering.|Metal.| Under.| Upper.| Con-|Metal.
| | | | | |crete|
-------------+--------+---------+------+-------+-------+-----+------
| in. | in. | in. | in. | in. | in. | in.
Country roads| 6 | 3 | 4 | 9 | 4 | 4 | 3
Suburban „ | 9 | 3 | 5 | 9 | 6 | 6 | 5
Town streets | 9 | 6 | 5 | 15 | 6 | 10 | 5
-------------+--------+---------+------+-------+-------+-----+------
Chalk has sometimes been used for the bottom of a roadway, but where
this is likely to be affected by frost it is the worst material that can
be used, as it is likely to blow up the roadway.
With regard to the annual outlay upon macadamised roadways, the
following comparative tables[20] prepared by Mr. Ellice Clark, the then
Surveyor of Derby, may be of interest.
---------------+-------+--------------------------------------------
| | Annual Outlay.
+-------+----+------+--------+-------+-------+-------
| | | Sink-| | | |
| | | ing | | | |
| | |fund 3| | | |
| Ori- | | per | | | |
| ginal | | cent.| | | |
| cost | | com- | | | |
| per | In-| pound| | | |
Description of| square|ter-|inter-| Main- | Scav- | |
Pavement. | yard. |est.| est. |tenance.|enging.|Gravel.|Total.
---------------+-------+----+------+--------+-------+-------+-------
|_s. d._|_d._| _d._ |_s. d._|_s. d._| _d._ |_s. d._
Wood pavement |15 1·5| 7·5| 10·1 | 0 1·0| 0 2·7| 5·0 | 2 2·3
| | | | | | |
Val de Travers | | | | | | |
compressed |18 0·0| 9·7| .. | 0 3·6| 0 0·4| .. | 1 1·7
asphalte | | | | | | |
| | | | | | |
Granite setts | | | | | | |
7 inches by | | | | | | |
3 inches laid| | | | | | |
over a layer |17 9·0| 9·6| 0·5 | 0 1·3| 0 2·5| .. | 1 1·9
of 12 inches | | | | | | |
of cement | | | | | | |
concrete | | | | | | |
| | | | | | |
Macadam in | | | | | | |
south of | 4 9·0| 2·1| .. | 3 6·0| 1 0·0| .. | 4 8·1
England | | | | | | |
---------------+-------+----+------+--------+-------+-------+-------
-------------+------------------+------------------
| Load of Mud |Traffic per Annum
Material. | per area. |per yard of width.
-------------+------------------+------------------
|superficial yards.| tons.
| |
Macadam | 344 | 25,000
Granite setts| 500 | 50,000
Wood | 1666 | 25,000
Asphalte | 4000 | 500,000
-------------+------------------+------------------
The following is a table of the cost of streets in Paris per square yard
per annum.[21]
------------------------+------------+----------+---------
Description of Pavement.|Maintenance.|Cleansing.| Total.
------------------------+------------+----------+---------
| _s._ _d._ | _s._ _d._|_s._ _d._
Stone Pavement | 0 4·50 | 0 3·37| 0 7·87
Macadam | 0 9·25 | 0 7·31| 1 5·26
Asphalte | 0 10·20 | 0 4·17| 1 2·37
------------------------+------------+----------+---------
The cost of maintaining macadamised roadways as compared with that of
granite setts has been said to be as high as 5 to 1 and that this cost
if capitalised for 12 or 13 years will equal the first expense, interest
on money, and the necessary repairs for a granite paved roadway.
The following table gives the cost per annum per square yard for the
maintenance of macadamised roadways in different places, so far as I
have been able to collect them:
_s._ _d._ _s._ _d._
Bristol 4 to 1 0
Charing Cross (London) 5 0 (now paved)
Exeter 6 „ 2 6 including
cleansing
Glasgow 8¹⁄₂
Leeds 10 „ 1 2
Liverpool 2 „ 2 6
Manchester 6 „ 1 8
Merthyr Tydfil 4¹⁄₂
Newcastle 1 3 including
watering
Paris 9¹⁄₄ „ 10 9
Parliament Street (London) 3 6 repairs only
Regent Street (ditto) 3 7 (now paved with
wood)
Stockton 9 „ 1 6
Sheffield 1 8 „ 2 0
Wakefield 1 0 all paved
streets now.
In Birmingham the macadamised streets have worn down 6 inches in one
year, with a traffic of 2484 vehicles passing in 10 hours.
With reference to the great cost of maintenance in Paris, the following
particulars[22] may here be given;
“The surface of the street is picked by gangs of men, metal from 2¹⁄₂ to
9 inches in thickness is then laid on, a coating of sand is then spread
upon it, it is watered and rolled at per kilometre ton, that is, at per
ton weight of roller per kilometre travelled, at a cost of about
15·33_d._ per ton mile for the first 250,000 ton miles, and at reduced
rates for additional service. The materials used for the roads are
flints costing 4_s._ 6¹⁄₂_d._ per cubic yard for light traffic roads;
for medium traffic, hard millstone at 11_s._ 4_d._; and for the heaviest
and greatest traffic, porphyry at 15_s._ 9_d._ The average total cost of
maintenance of the streets is 1_s._ 8¹⁄₂_d._ per square yard per annum
for the first-class roads, and 1_s._ 1¹⁄₂_d._ for the lighter traffic;
the highest cost for maintenance is as high as 10_s._ 9_d._ per square
yard, the lowest 9¹⁄₄_d._ per annum.”
It may be well to mention that 73 per cent. of the streets in Paris are
paved, 5 per cent. are coated with asphalte, and 22 per cent. are
macadamised.
The contour, or best form of cross section that should be given to a
roadway, has often exercised the minds of engineers, but for all
practical purposes evenness of surface and regularity of section in a
macadamised roadway are of more importance than the slight difference
between straight lines and curves, which might only tend to confuse the
workmen. Formerly it was the practice to employ a complicated gauge in
the form of a straight-edge fitted with plummet or level and sliding
bars, but a good eye, assisted by a long straight-edge and spirit-level
and three boning rods, is generally found to be sufficient, and if the
centre of the roadway is kept level with the heel of the footpath, a
sightly cross-section is generally the result; or say 6 inches to 9
inches higher in centre of a roadway 30 feet in width between the kerbs,
3 inches to 4 inches where it is from 18 to 20 feet in width.
The following detailed section of a macadamised roadway is one which I
am in the habit of specifying for suburban districts, as it is easily
set out and constructed, and answers all purposes most admirably.
[Illustration]
The total width of street is 36 feet, of which the roadway takes 24,
leaving a footpath 6 feet in width on each side.
The surface of the finished roadway is a segment of a circle, the crown
being level with the heels of the footpaths on each side; the formation
surface is parallel with it, and of course the depth of this and the
thickness of foundations and metal must depend upon local circumstances.
It will be seen that the haunches are drained with 3-inch common
drain-pipes. This may be omitted if the ground is thoroughly dry, but it
is often a great help to a road.
The paths, kerbing, and channelling will be described in their
respective chapters.
It must be borne in mind that on a perfectly level road a more convex
section is necessary than on a gradient.
It is wrong to make the sides of a roadway weaker than the centre,
especially in streets with shops on each side, or on hills where drags
are likely to be used. On hills, too, be it remembered, the channels
should take the surface water; any ruts from wheel tracks acting as
watercourses are disastrous. Hauling timber on a macadamised roadway is
also very damaging.
The great objections to macadamised roadways are as follows:--
(1.) They manufacture too much mud and dust.[23]
(2.) They are too absorbent.
(3.) They are very noisy and damaging to vehicles and horses when fresh
metalled.
(4.) They constantly require mending, but never seem quite sound.
(5.) They are frequently encumbered by men and carts engaged in either
repairs, cleansing, or watering.
(6.) They are very expensive to maintain and cleanse.
(7.) They are bad for a horse to fall upon, as such falls generally
damage the knees.
The following notes upon the maintenance of macadamised roadways may
here be of service:--
(1.) Roads should be inspected in wet weather, as hollows and other
imperfections are then easily detected; a hollow place extends very
rapidly if neglected.
(2.) All ruts should be filled in at once. If there are three parallel,
the centre rut should be first filled in; the traffic is thus slightly
diverted, as a horse will avoid new metal.
(3.) Ruts should not be allowed to form; the surface of the road ought
never to lose its regular section.
(4.) A road should be thoroughly repaired directly it shows the least
sign of being fairly worn all over.
(5.) The right season of the year for repairs is the autumn, although
where a steam roller can be used almost any time will do. If the surface
of the road is very hard it should be “lifted”[24] previous to repairs.
(6.) All loose stones should be picked off at once or put together in
hollow places upon the roadway, as, if allowed to remain, they are not
only dangerous to horses, but are liable to be crushed, or to be forced
through the skin of the roadway, thus causing it damage.
(7.) Water lodging upon a road does great mischief, but it should not be
let off by digging a trench with a pickaxe to the side of roadway, as is
sometimes done.
(8.) A roadway when very dry sometimes suffers through disintegration of
the surface.
(9.) Scraping the mud off a roadway may damage it by loosening stones;
sweeping the surface when wet is best.
(10.) A heavy shower does a road good by washing it; a continuous
drizzle, especially after frost, is very ruinous to a roadway.
(11.) A good cleansing is sometimes worth a coat of metal.[25]
_Bituminous Roadways._
In some towns in England bituminous or asphalte macadamised roadways are
made. This consists in mixing ordinary coal tar with the road metal
ordinarily employed for macadamised roads, only it must be borne in mind
that the metal employed must be limestone or some other soft material,
otherwise it will not wear down evenly with the tar, and thus a lumpy
surface will be produced in course of time.
The method of mixing is by heating the stone, which has of course been
previously broken to the required size, and then thoroughly mixing and
incorporating it with the tar. This is then carried to the roadway, is
spread in the ordinary manner and well rolled to the proper contour, a
surface being afterwards given to it by a coating of about 2 inches
thick, composed of a similar mixture, the stones of which are of much
smaller size.
Another method is to place about 6 inches of the broken metal described
above upon the necessary foundation. Upon this a boiling mixture
composed of about 50 gallons of creosote oil and 1 ton of pitch is
poured until every interstice is filled with the mixture. Whilst this is
still warm, a thin layer of small broken stone is spread upon the
surface and well rolled; more small stones or chippings are added, and
the whole is rolled until the surface of the roadway has attained its
proper contour and presents a perfectly smooth and clean appearance,
little inferior to that of real asphalte.
Dry weather is essential whilst this class of roadway is in course of
construction, and they require careful watching, as, upon the skin
becoming broken, the whole roadway soon breaks up. They have, however,
many advantages over ordinary macadamised roadways when finished, not
the least of them being their imperviousness to moisture, and the ease
with which they are cleansed.
[12] The first road “engineer” in this country was John Metcalf of
Knaresborough, who was born in 1717, and who, although totally blind,
was the first person to introduce a methodical system of road repairs.
_Vide_ ‘Roads and Road Makers,’ by Henry Alexander Glass.
[13] _Vide_ ‘A Treatise on Roads,’ by Sir H. Parnell (1833).
[14] The total width of roadway being thirty feet.
[15] It is necessary to give a new roadway more convexity than it will
have when finished, for however carefully it is raked or attended to
when being rolled, the top is sure to flatten and spread towards the
haunches.
[16] Instead of parallel lines it is sometimes well to place these
stones diagonally from centre to kerb or “herring-bone” fashion, thus
greatly facilitating the under drainage.
[17] In metalling a road it is better to put on the coats gradually,
than to give the whole thickness of metal at once.
[18] The method adopted in Chicago, U.S.A., for forming their roadways
is as follows:--The road bed is prepared of the proper contour and
well-rolled with a 15-ton steam roller until it is even, firm, and
compact; on this bed rubble stone is carefully placed by hand with its
broadest surface downwards, then 12 inches of metal are added 6 inches
at a time, thoroughly rolled to bond it well, it is then topped with 4
inches of crushed trap rock or some other equally hard stone, which
will not disintegrate through the action of the weather, nor pulverise
under the pressure and wear of vehicles upon it; this is again,
thoroughly well rolled so as to compact and bind it together.
[19] “If roads be kept dry they will be maintained in a good state
with proportionally less expense. It has been well observed that the
statuary cannot saw his marble, nor the lapidary cut his jewels
without the assistance of the powder of the specific materials on
which he is acting; this, when combined with water, produces
sufficient attrition to accomplish his purpose. A similar effect is
produced on roads, since the reduced particles of the materials, when
wet, assist the wheels in rapidly grinding down the surface.”
Parnell’s ‘Treatise on Roads,’ 1883. More modern writers have likened
macadamised roadways to “stone mills on which the stones are ground
into dust when dry, or mud when wet.”
[20] _Vide_ ‘Minutes of Proceedings of the Institution of Civil
Engineers,’ vol. lx.
[21] _Vide_ ‘Annales industrielles de Paris,’ Oct. 21st and Nov. 4th,
1877.
[22] _Vide_ ‘Annales industrielles de Paris.’
[23] A report of the Paddington Vestry on “wood and other pavements,”
(1878) states macadam as a mud producing material is twelve times
worse than wood, and six times worse than granite cubes.
[24] This is also sometimes called “stocking” or “chequering,” and
consists of making furrows across a roadway with a sharp pickaxe,
about a couple of inches in depth, thus removing any irregularities,
and also allowing the new metal to bed properly.
[25] In Birmingham, good cleansing is said to have reduced the amount
of metal necessary for the maintenance of the roadways from 20,000
tons per annum to 13,000 tons.
CHAPTER VI.
ROAD METAL AND BREAKING.
The only true test of the fitness of any stone for use as a road metal
is by an experimental trial upon a certain length of roadway; but in
making the first selection for such trials it is well to make the
following investigations:--
(1.) Ascertain from local persons, such as masons, quarrymen, and
others, their opinion of the qualities of the stones in the
neighbourhood.
(2.) Make a trial of the stone for toughness. This can be done by
setting a good stone-breaker to work upon a heap of the stone as
quarried and carefully watching how much he can break in an hour.[26]
(3.) Ascertain what power the stone has to resist abrasion. This is done
in France by putting the broken metal into a revolving cylinder and then
carefully noting by weight what the cubes lose by contact with each
other. Another plan may be adopted by pressing the stone against a
grindstone with a uniform pressure, and noting the loss caused by such
contact.
(4.) The power to resist compression may be easily ascertained by
placing small cubes in an hydraulic press and noting under what
pressures each cube will crush.
(5.) The effect of weather is not easily ascertained artificially,
although it is suggested that a good test may be made by soaking the
stone in a saturated solution of sulphate of soda; and then on exposure
to the air, if soft, it is said the stone will disintegrate as if under
the action of thaw succeeding frost.[27]
The specific gravity of a stone is no criterion whatever as to its
fitness. Clay-slate has a higher specific gravity than a tough flint,
and yet the former is almost useless as a road metal; the latter, on the
contrary, often making excellent roadways.
The qualities necessary for a really good road metal are hardness,
toughness, not easily decomposed or affected by the weather, and at the
same time the stone when broken ought to have some power of cohesion
without the necessity of much binding material. The question of cost I
put aside at once, as it is well known that the best road metal is
always the cheapest where there is much or heavy traffic.
Local circumstances must to a great extent determine what stone to use
upon a roadway, but the following list may be of use:--
_Syenite._--This is a granite in which hornblende takes the place of
mica, and is an excellent road material; the darker the colour the more
durable it is found to be.
_Granite._--This should have more felspar than quartz, and have as
little mica as possible; the closer the grain the better. Coarse-grained
granites soon decompose.
_Trappean Rocks._--Some of these are excellent for road metal. Basalts
of dark colour and close grain should be selected. Greenstones with
similar characteristics are good; as is also Whinstone.
_Gneiss._--Is inferior to granite; it has mica in layers and is not a
good road metal.
_Clay Slates._--These are useless, as they crumble on exposure or
degenerate into mud.
_Limestone._--The Metamorphic, Silurian, and Carboniferous limestones
may be used if crystalline in appearance, but the Lias and Oolitic are
of little use.[28]
_Sandstones._--Some of these, if cherty or containing a large percentage
of iron, may be used; but as a rule they are quite unfitted for use as a
road metal.
_Flints._--These, if tough, make excellent roadways; but unfortunately
they are sometimes too brittle for heavy traffic. Surface-picked flints
are better than those from a quarry.[29]
_Pebbles._--These are found on sea shores and river beds. They are
composed of very various rocks, and are much water-worn and rounded;
when broken they sometimes answer very well if mixed with gravel to bind
them.
_Gravel._--This, if of a flinty character, and not too much mixed with
earthy matter, makes good roads for light traffic, if carefully watched
or well rolled during formation. Pit gravel should always be screened
through wire screens of 1¹⁄₂ to 1³⁄₄ gauge, and the small can be used
for footpaths.
In some places it is difficult to obtain any natural stone for the
purposes of road metal; in these cases slag from blast furnaces or
ordinary clinkers from furnaces are sometimes used. Oyster shells are
used on the roadways near the Gulf coasts[30] and charcoal in Michigan,
United States.[31] I have myself made a most excellent roadway with
coral on the coast of Jamaica, and no doubt many strange materials have
been, and still are, used for this purpose.
“I never mix” is an adage that should be followed by surveyors as
regards road metal. Do not mix a soft material with one that is harder
for either construction or maintenance of a roadway; the effect is what
is known as a “bumpy” road, arising from the fact of the soft stone
wearing faster than the hard. The hardest metal should be kept for the
top or surface layer of the roadway.
As an instance of the extreme difficulty besetting the question of the
best material for road metal, I will here give a table showing the
comparative coefficients of quality assigned to them by the engineers of
the French Department of the Ponts et Chaussées.[32]
COEFFICIENTS OF QUALITY OF ROAD MATERIALS.
Granitic gravel 23·8
Quartz gravel 21·4
Trap 20·0
Quartz 10·0 to 25·0 (in one instance 4·8)
Basalt 12·0 „ 20·0
Porphyry 10·0 „ 20·0 (in one instance 5·0)
Quartzite 11·0 „ 18·0
Devonian schist 16·0
Schist 4·0 to 12·0
Sandstone 12·0 „ 16·0
Granite 6·0 „ 20·0 (generally 10·0 to 12·0)
Syenite 12·0
Gneiss 9·0 to 12·0
Silicious pebbles and gravel 8·0 „ 19·0 (in one instance 6·0)
Silex 8·0 „ 16·0
Chalk flints 7·0 „ 11·6
Silicious limestone 6·0 „ 18·0 (generally about 10·0 to
12·0)
Compact limestone 14·0
Magnesian limestone 16·0
Carboniferous limestone 9·0
Oolitic limestone 5·0 to 12·0
Lias limestone 5·0 „ 10·0
Juranic limestone 5·0 „ 8·0
Limestone 5·0 „ 12·0
Mean of all France 10·63
It will be seen by the above table how different are the results
obtained from materials of the same character.
Breaking stone for the purpose of using it as a road metal was, until
comparatively recent years, always effected by hand; now, as in other
cases, machinery has stept in and somewhat supplanted manual labour.
Hand-broken road metal, however, still finds favour with road surveyors;
it is better broken, and in some districts, the occupation finds
employment for persons who otherwise would be thrown on the rates for
support.
In breaking stone by hand the breaker sits and strikes the stone with a
small cast-steel chisel-faced hammer, weighing about one pound, at the
end of a long, straight-grained but flexible ash stick.[33] The breaker
also has another hammer, weighing about five pounds, with which he
reduces the size of the large stones before breaking them into the
proper size for road metal. This latter size is often a matter of
choice, some engineers preferring it to be broken so small as will pass
through a ring of only 1¹⁄₂ inch in diameter; others are content with 3
inches, especially where the roads are steam rolled. An old method of
gauging used to be “such a size as the stone breaker could put in his
mouth,” but this was unsatisfactory to all persons concerned, and “to
pass all ways through a ring of 2¹⁄₂ inches internal diameter” is now
the size most generally adopted.
Mr. Codrington says[34] “a good stone breaker will break 2 cubic yards
of hard limestone to the ordinary gauge in a day, and some men will
break more. Hard silicious stones and igneous rocks can only be broken
at the rate of 1¹⁄₂ or of 1 cube yard per day; of some of the toughest,
such as Guernsey granite, a man can only break on an average half a cube
yard per day. River gravel, field stones, or flints, which are already
of a small size, can be broken at the rate of 3 or 4 cube yards per
day.”
This may be taken as fairly representing a day’s work, the price for
breaking however must vary considerably in different localities on
account of the variety of the stones to be broken and the value of
labour; in some districts the road metal does not cost more than 1_s._
per cube yard, in others 2_s._ 6_d._ and 2_s._ 8_d._ is not considered
too high, and it was to meet and reduce this great expense that steam
stone-breaking machines have been introduced. These machines are known
as “Ellison’s,” “Newall and Archer’s,” “Hope’s,” and “Blake’s,” the
latter being that which is best known and most generally used in this
country.
[Illustration: “ARCHER’S” STONE BREAKER.]
[Illustration: “BLAKE’S” STONE BREAKER.]
[Illustration: “NEWALL AND ARCHER’S” STONE BREAKER.]
The foregoing illustrations will give a general idea of the manner in
which the stone is broken or crushed between strong iron jaws; in all
cases a revolving perforated screen is necessary (not shown in the
drawings) to separate the stone broken to proper gauge from that which
is too large, and also from the spalls or chippings.
The Blake’s or “Blake Marsden’s” machines are of various sizes and
weights; the following particulars with respect to them, as advertised,
may be of use.[35]
------------+----------+---------+---------------+-------------
Size of | | | |
machine at | Approxi- | | Total weight |
mouth, | mate | | of machine |
showing what| quanti- | | with wheels, |
size of | ty of | Nominal | axles, horse |
stone each |road metal| horse- | shafts, auto- | Price of[36]
machine will| broken | power |matic screening| machine
take. | per hour.|required.|apparatus, etc.| complete.
------------+----------+---------+---------------+-------------
inches. | cube | H.P. | tons cwt. qrs.| £ _s._ _d._
| yards. | | |
10 × 8 | 3¹⁄₃ | 3 | 5 6 0 |157 0 0
12 × 8 | 4 | 3 | 5 11 0 |167 0 0
15 × 8 | 5 | 5 | 6 19 0 |200 0 0
15 × 10 | 6 | 6 | 8 5 0 |220 0 0
20 × 10 | 8 | 8 | 10 2 0 |265 0 0
24 × 13 | 12 | 10 | 15 5 0 |390 0 0
24 × 17 | 13 | 14 | 16 2 0 |415 0 0
24 × 19 | 14 | 16 | 19 17 0 |440 0 0
30 × 13 | 14 | 16 | 16 2 0 |440 0 0
------------+----------+---------+---------------+-------------
Mr. Till, the Borough Engineer of Birmingham, speaking of the work done
by one of Blake’s machines in 1874, says:[37] “The stone-breaking
machine at Holliday Street will break on an average 40 tons of ragstone
per day, at a cost, exclusive of wear and tear of machine, of 10¹⁄₂_d._
per ton, but it produces 16 per cent. of dust or fine stone; of the
remainder one-fifth has to be rebroken by hand, the whole is very
irregular in size and very flaky in comparison with hand-broken stone.
The machine is much more efficient in breaking granites or pebbles. It
has, however, been found very useful during the last two years, in
consequence of the difficulty of obtaining labour.”
Mr. Jacob, the Borough Engineer of Barrow in Furness, read an excellent
paper on the subject of stone-breaking machinery to the members of the
Association of Municipal and Sanitary Engineers, at their meeting in
Manchester in 1875,[38] giving a full description of one of Blake’s
machines, to which I will refer my readers.
Mr. Codrington[39] gives the result of breaking whinstone in a 16-inch
by 9-inch Hope machine, from which it appears that the total cost,
including wages, coal, oil, cottonwaste, etc., wear and tear of
machinery, and, I presume, interest on first cost of machine, was about
1_s._ per cube yard. This effected a saving of 10_d._ per cube yard as
compared with the same stone broken by hand, and the machine broke 40
tons of stone per diem.
To make a stone-breaking machine pay, it is necessary:
(1.) To give it nearly constant work.
(2.) That the stone to be broken shall be too tough to break
economically by hand.
(3.) That the machine shall be at the quarry, so as to save the expense
of much handling.
(4.) To exercise care in feeding, to give it a sufficient supply without
allowing an undue quantity of stone to pass in at one time.
(5.) As about 20 per cent. of grit or dust is produced, this must be
used for foot-paths, or as a binding material for roads, or in asphalte
or tar paving.
In addition to the grit which is produced, a great many long and thin
pieces of stone pass through the machine, which have to be again broken
by it before they could be used as road metal; and having once taken
this form, they will frequently pass several times through the machine
before they get properly broken.
The wear and tear of a stone-breaking machine is very considerable, as
can be easily imagined; it has been known to reach as high as 62·5 per
cent.[40] of the first cost of the machine in one year. The objections
to stone-breaking by machinery are principally:
(1.) In some districts labour can be successfully employed in this
manner.
(2.) Hand-broken stone is sharper in fracture, as it is done by a blow
and not by gradual pressure, whereas machine-broken stone is often flaky
or with rounded edges, and frequently each stone may be cracked and
shaken by the pressure.
(3.) Want of uniformity in the size of the stones.
The smaller the stone is broken the heavier a cubic yard of it will
weigh, as the percentage of vacant space between each stone will be
less. It has been found by experiment, however, that 55 per cent. of
ordinary road metal is solid, so that the weight of a cubic yard of it
can easily be ascertained in the following manner.[41]
Multiply the weight of a cubic foot of any stone by 27 to bring it to a
cubic yard, and then multiply this by 0·55: the result will be the
weight of a cubic yard of the same stone when broken for metalling.
A cubic yard of Guernsey granite broken to pass through a 2¹⁄₂ inch ring
has been weighed, and gives an average of 1 ton 3 cwt. 2 qrs.
tons cwt. qrs.
A cube yard of flint weighed 1 1 3
„ „ pit gravel weighed 1 4 3
„ „ limestone weighed 1 3 0
A cubic yard of ordinary broken road metal will, when properly spread,
cover an area of about 30 square yards of surface of a roadway.
The following specimen specification for the supply of stone either
unbroken or broken may be of use.
_Specification for the Supply of Road Metal._
(1.) The road metal must at all times be clean and free from clay or
other dirt, and fully equal to the sample; if required to be broken,
each cube must have a square face and sharp edges, and pass all ways
through a 2¹⁄₂ inch ring.
(2.) The metal must be delivered in (_name of town_) free of all charge
to the corporation, either at a railway station or at one of the depôts
of the corporation, at the option of the contractor, such option to be
declared in the tender.
(3.) The metal must be supplied on the order of the borough engineer in
such quantities as he may specify, and must be delivered within the time
specified in the order. The contractor shall not be required to supply
and deliver more than tons in any one week; but the corporation will
be at all times ready to take the metal in larger quantities.
(4.) The bill of lading or railway invoice shall be taken as _primâ
facie_ evidence of the weight of metal supplied; but the corporation
retain the right to test the accuracy of such bill of lading or railway
invoice, by passing the metal over a weighbridge as it is received.
(5.) Metal delivered at a depôt by carts shall be measured when broken
and paid for at the rate of cwt. per cubic yard.
(6.) The corporation retain the right to reject all metal which shall
not be equal to the sample, or at their option to pay a reduced price
according to its value.
(7.) Quarterly payments will be made by the corporation on the
certificate of the borough engineer, and within one month from the date
of such certificate.
(8.) The borough engineer shall be the sole judge as to the fitness of
the metal supplied, and his certificate, in writing, shall be conclusive
evidence upon the point as between the corporation and the contractor.
(9.) If the contractor shall make default in the supply and delivery of
road metal in accordance with the terms of this specification, and
within the time specified for the purpose in the order of the borough
engineer, the corporation shall be at liberty to obtain such road metal
as they may deem fit and necessary from another source, and any excess
in price or other loss they may consequently incur, shall be recoverable
by them from the contractor as liquidated and ascertained damages.
(10.) Tenders must be sent in only on the prescribed form, and the
person tendering must insert in his tender the name of two persons who
will join him in a joint and several bond to the corporation in the sum
of _l._ for the due performance of the contract.
(11.) Each person tendering must send to the office of the borough
engineer a sample of the road metal he offers, accompanied by a full
description, and the name and position of the quarry from which it is
produced; such sample to be not less that one cwt. in weight, and to be
retained by the corporation in the event of the tender being accepted.
(12.) The corporation do not bind themselves to accept the lowest or any
tender; and they further retain the right to reject a contractor in the
event of his failing to find sureties to their satisfaction in
compliance with the 10th condition.
(13.) The word “corporation” shall mean the mayor, aldermen and
burgesses, of in their capacity as the urban sanitary authority
for . The word “contractor” shall mean the person whose tender is
accepted, and who has signed these conditions; and the words “borough
engineer” shall mean the engineer to the said corporation for the time
being.
Since writing this chapter my attention has been directed to a
stone-breaking machine which is said to substitute a “knapping” for that
of the usual crushing motion which is so generally the great defect in
these machines: I allude to that known as “Baxter’s patent
knapping-motion stone breaker,” by which a rapid jerk or blow is given
instead of the slow crushing movement, thus (it is contended) causing
less waste from dust and chippings, and also less strain of the
machinery and less power to drive it.
[26] Toughness is not all that is required. Leather would be very
difficult to break with a hammer, but it would not make a good road
metal.
[27] I have tried this experiment, but without success, except on such
soft stones as were evidently unfitted for use as a road metal.
[28] Many hundreds of miles of roadways in this country are made with
limestones; they often make an excellent surface, as they possess a
considerable power of binding together, but weather and very heavy
traffic affect them considerably: as they all have a strong affinity
for water, their very power of thus cementing themselves together
causes a quantity of dust in dry, and mud in wet weather.
[29] A flinty or quartzose stone seems to harden with exposure. This
is notably the case in pebbles; old pebble paving taken up and broken
makes a most hard and durable road metal.
[30] ‘Roads, Streets and Pavements,’ by Q. A. Gillmore, p. 10.
[31] _Ibid._
[32] _Vide_ ‘The Maintenance of Macadamised Roadways,’ by Thomas
Codrington, p. 33, a most excellent work upon this subject.
[33] Mr. W. Bold considered a hammer weighing 1¹⁄₄ lb. of an
elliptical form, pointed at the ends, the area of each end being about
¹⁄₁₀₀th of a square inch, to be the most suitable to break hard
stones. _Vide_ ‘Minutes of Proceedings, Institution of Civil
Engineers,’ vol. i. (1840) p. 50.
[34] ‘The Maintenance of Macadamised Roads,’ by Thomas Codrington, p.
38.
[35, 36] No doubt the price of the machine varies with the price of
iron, etc.
[37] _Vide_ ‘Report of the Borough Surveyor of Birmingham to the
Paving and Street Improvement Sub-Committee,’ p. 11.
[38] _Vide_ ‘Proceedings of the Association of Municipal and Sanitary
Engineers,’ vol. ii. p. 76.
[39] _Vide_ ‘The Maintenance of Macadamised Roadways,’ by Thomas
Codrington, p. 41.
[40] _Vide_ ‘Proceedings of the Association of Municipal and Sanitary
Engineers,’ vol. ii. p. 82.
[41] _Vide_ ‘The Maintenance of Macadamised Roadways,’ by Thomas
Codrington, p. 45.
CHAPTER VII.
ROAD ROLLING.
The march of civilisation has decided that road rolling is a necessity
for macadamised roads, instead of allowing the stones of which they are
composed to be worn in by the traffic, as was formerly the custom. In
Calcutta bullock rollers were used so long ago as the year 1855, and it
was the cruelty of this operation that suggested to Mr. W. Clark the
necessity for a steam roller,[42] the outcome of which was the
well-known roller as manufactured and supplied by Messrs. Aveling and
Porter of Rochester, and now so generally used throughout this country,
as well as in American and other foreign towns.[43]
Steam rolling saves money as well as suffering, and the legislature have
recognised the importance of a sanitary authority becoming possessed of
a steam roller by permitting money to be borrowed for the purchase of a
roller as for a permanent work. (Sect. 234 Glenn’s Public Health Act
1875, footnote to Sub. Sect. (1).)
Mr. Albert W. Parry, the Borough Surveyor of Reading, has prepared some
tables on the subject of steam road rollers, from information he
received on this subject, in answer to some questions he addressed to
the surveyors of a number of towns a few years ago. It appears from this
tabulated statement that thirty-three 15-ton steam rollers were in use,
six 10-ton rollers, one 21-ton roller, one 8-ton roller, one 9¹⁄₂ ton
roller, one 14¹⁄₂-ton roller, one 17-ton roller, and one 25-ton roller;
this latter not being much used, as it was found to be too heavy.
The average gross cost per annum of necessary repairs to the rollers,
other than those which could be effected by the men in charge of it,
amounted to 35_l._ 12_s._ The number of men employed to attend to the
roller and cost of labour per day varied considerably, from one case
(South Shields) where “one engine-man at 26_s._ per week, and an old
scavenger with the flag” were found to be sufficient; to another
(Gloucester) where the cost per day is stated as follows: “one man works
the engine at 5_s._ per day, one boy with signal flag, 1_s._ 8_d._, two
men spreading gravel or sand at 3_s._, two men watering and sweeping to
keep water from running off in channels.”
Some of the older rollers require a steersman as well as a driver, and
the Locomotives Amendment Act requires two men with flags, but this is
seldom really necessary. The sweepers, spreaders and sprinklers should
be taken as irrespective of the actual cost of the roller, which may
therefore be assumed to be the wages of the engine-man, say 5_s._ per
diem, and a boy or old man with a flag at 2_s._, thus making a total for
labour of 7_s._ per diem.
The fuel that is consumed by a 15-ton roller seems to be from 3 to 5
cwt. of coke per diem, common gas coke being generally used, though
steam coal would no doubt answer equally well, some of the smokeless
Welsh descriptions being of course necessary.
With regard to the question “When not used for rolling roads, to what
other use (if any) do you put the engine power?” there are not many
towns that use the machine for any other purpose than rolling, but the
following uses may be enumerated to which the machines have been
applied:--Driving a stone-breaker, a mortar-mill, a saw-bench, a
chaff-cutting machine, a bean-crusher, etc. It has also been used in
connection with pumping, and to produce the necessary power for the
electric light, and it is frequently employed as a traction engine.
The driving rollers usually have provision by which spikes may be fitted
into holes in their faces, in order that they may be used for lifting or
chequering roads. These, however, apparently do not answer; the working
of a machine in this manner is said to shake and strain it considerably,
and the holes in the rollers, which are plugged with wood when not in
use, are objectionable, as these plugs wear out and the road metal gets
into the holes, and the surface of the road is picked up as the rolling
proceeds; besides this, the spikes seem to have no effect unless the
surface of the roadway being operated upon is soft.
With reference to the use of binding material, the most commonly used
and that which receives most favour is road grit or scrapings,[44] sharp
sand is also employed, as well as gravel if clean, and also stone
chippings and screenings; these should be of the same material of which
the road is made, if possible, and no doubt _newly_ constructed roads
require more care in the binding material than simple repairs. The
steepest gradient upon which a roller will act appears to be 1 in 9 in
Blackburn, with a 15-ton roller, but this must require a very heavy
pressure of steam, and 1 in 14 seems to be a gradient that gives no
trouble to roll either up or down; in going down hill, of course it is a
mere question of sufficient break power.
The number of superficial yards rolled per day must vary extremely with
circumstances: the class of material, the amount of binding and water
used, the gradient and pressure of steam maintained, and the amount of
rolling considered necessary,[45] being amongst the various influences.
From the above returns I find that the number of square yards rolled
varies from 500 to 3000 per diem, the average for 42 towns being 1105
square yards per diem.
The cost per square yard rolled, including all charges, may be assumed
to be between ¹⁄₂_d._ and 1_d._, and the cost of binding material about
3_d._ per square yard. With reference to the necessity of binding
material, the following, facts are interesting.