A ^^ ' ' ' .- / .' / ,-- .' ' . /7-^^^>/ c_' ^ x s " r /fs ^ ; ; > -a - ' d. per ton more than ungauged sets, there is eventually a considerable saving in specifying that they be accurately gauged prior to leaving the quarry. As regards the width of the joints of the sets, these cannot, in my opinion, be too small. It is a mistaken notion to suppose that the width of the joints makes the pavement in any way safer, as the inequali- ties of the sets give sufficient foot-hold. Wide joints are open to very great objection on many grounds, and when these joints are grouted in lime or cement instead of pitch and creosote oil they often become the receptacles for all filth. [The italics are ours.] New York Specifications. The New York specifications permit i -inch joints, which are not grouted at all, while the blocks, as already stated, are specified to be from 8 to 12 inches long, 3^ to 4^ inches wide, and 7 to 8 inches deep. And these specifications, it is officially announced, are not ex- pected to be adhered to. Probably no city in the world has heavier traffic or better stone pavements than Liverpool, and it would be well to profit by the experience there gained. There is every facil- ity for doing equally good work in New York, and the generous ap- propriation recently made for improving the pavements shows that the city is willing to pay for the best and expects to get it. And it is to be regretted that so competent an executive officer as Commis- sioner Gilroy should so far forget himself as to talk on a subject on which he can not be expected to be an expert, and evidently has yet a great deal to learn, and announce the dangerous doctrine that the department's specifications are not expected to be enforced. VIOLATION OF SPECIFICATIONS ON THE CEDAR STREET PAVEMENT WORK.* As we go to press a member of our staff has discovered that in the new paving work which is to be done under the recent three million dollars appropriation, in Cedar Street, New York, a large number of the blocks on the ground, /. e., sidewalk, exceed the size called for in the specification, which permits a variation of 8 to 12 inches in length, 3^ to 4^ in width, and 7 to 8 in depth. A number of these blocks measure from 12 to 19 inches in length and from 4-| to 5 \ inches in width, and this extra width is a most serious defect. The specifications, based upon the experience of engineers in all the *xx, 346. 2O STONE PAVEMENTS. cities that have decent pavements, explicitly provide (the clause be- ing in italics), that none of the old pavement can be disturbed while any unfit or rejected material remains on the ground. In defiance of this clear and most important provision the street is torn up from Nassau to Pearl Street, traffic is suspended, the street is a mud-hole, and store-keepers are subjected to loss. We suggest that our con- temporaries of the daily press give this matter their attention. Mer- chants on the street should be able to recover damages from parties responsible for causing this needless interruption to their business. i GRANITE BLOCKS VS. ASPHALT IN CINCINNATI.* About $2,000,000 will be spent on paving the streets of Cincin- nati during 1887, with either granite blocks or asphalt. About one mile and a half of one street has been laid in asphalt, while several miles have been laid in granite blocks. The latter is deemed best for heavy hauling, but the former shows no sign of wear, although put down last summer, and since then subjected to the severest test, as, owing to its smoothness, all sorts of vehicles have crowded upon it. Citizens living on streets yet to be paved are petitioning for asphalt instead of granite blocks. If the same care is taken with laying the streets next year as was this, Cincinnati will have the smoothest roadways of any city in the United States. GRANITE, SANDSTONE AND LIMESTONE FOR PAVING. f A report on pavements, made to the Common Council of Topeka, Kan., refers to stone pavements as follows : For this use, Medina and Colorado sandstone, they say, take first rank as to durability. Omaha and Kansas City are using Sioux Falls and Mis- souri granite. While the granite may be somewhat more lasting, the sand- stone is very durable, is less noisy, and has the advantage of not becoming polished or glossy in use. Hard Argentine limestone was tried in Kansas City on a concrete foundation, but, being set on edge, it wore unevenly, and in a year or two was shivered and split by the frost, and has had to be replaced by granite and limestone. This is the universal experience of all cities using limestone blocks. Captain Greene, of Washington, states that granite pavements there have given satisfaction, except on the score of noise. This has led to its restriction to streets having exceptionally heavy traffic, and a desire for the substitution of asphalt even on these. xv, 20. f xv > 375- CHAPTER II. WOOD PAVEMENTS. WOOD PAVEMENT IN THE METROPOLIS.* SINCE wood and asphalt pavements have been extensively adopted in the best paved thoroughfares of London and Paris, and since the American experience with wood pavements has been unsat- isfactory because of the improper methods adopted in laying them, and lack of care after being laid, we have thought it well to reprint in this series the paper by George Henry Stayton, Assoc. M. Inst. C.E., with an abstract of the discussion thereon, which was had before the Institution in 1884. Though the paper deals with wood pavements, for which the author apparently has a preference, yet with the discussion and crit- icism it elicited it is a valuable contribution on this subject, which our American readers will, we believe, appreciate. The necessity for stimulating the efforts of those persons who are act- ively engaged in the construction and maintenance of street carriageway pavements in the metropolis and large cities was strenuously urged during the discussions at the Institution in 1879, when the subject was brought for- ward by Mr. Deacon and by Mr. Howard. The object of this paper is to call attention to the various wood-pavement works recently executed in the metropolis, and to a comparison of the results obtained thereby. Although the paper may not contain much that is new, the author ventures to think that the general interest evinced in works which tend to the efficient and economical maintenance of the carriageways of important thoroughfares, and the direct bearing which such works have upon the comfort and con- venience of a community, may be sufficient to justify a review of the pro- gress in this system of pavement, It may not be uninteresting to consider for one moment the extent of the streets of the metropolis, and the nature of the materials of which the carriageways thereof are formed ; and the author desires to tender his warmest acknowledgments to the president, who in his official capacity as the Chief Engineer to the Metropolitan Board of Works furnished him with valuable data, and to Mr. W. Haywood, M. Inst. C. E., the city engineer, and to forty-three chief surveyors of parishes and districts of the metropo- lis, for their courtesy in replying to his communications thereon. The in- formation thus obtained has enabled him to present it in the tabulated form which will be found in Table I. in the appendix, according to which it ap- pears that at the commencement of the present year the aggregate length * xvi, 322. A paper by George Henry Stayton, Assoc. M. Inst. C. E. , and printed in the Minutes of the Proceedings. 22 WOOD PAVEMENTS. of the streets of London amounted to 1,966 miles. Of that length, how- ever, 248 miles are at present " new" street, inasmuch as they have not been adopted by a local authority; consequently there are 1,718 miles of public streets under the maintenance of the various authorities, the car- riageways of which consist of the following materials viz. : Miles. Macadam 573 Granite 280 Wood 53 Asphalt 13^ Flints or gravel 798^ Total 1,718 The extent of the vehicular traffic is equally remarkable, the result of inquiries instituted by the author showing that in the metropolis alone, at the present time, there are approximately 100,000 horses and 40,000 vehicles, the licensed cabs numbering 10,381, and omnibuses, etc., 2,223, and the es- timated value of the horses, harness, and vehicles amounts to no less than ,5, 000,000 sterling. Obviously the ordinary wear and tear of these vehicles must in a great measure depend upon the condition of the street carriageways. No doubt many members of the Institution have a vivid recollection of the extremely unsatisfactory state of those macadamized carriageways in leading West-end thoroughfares, which have given place to wood pave- ment. It was rarely the case that such roadways were in a good state of repair ; on a hot summer day they invariably emitted disagreeable smells and frequently gave off a great amount of dust ; and it is scarcely possible to conceive anything more deplorable than the state of such streets when- ever the surface became greasy or sloppy after rain. All things considered, there was not only undoubted cause for dissatisfaction, but ample justifica- tion in the outcry against the former state of things ; as, what with damage to horses, harness, vehicles, and pedestrians' clothing, together with the sheer waste of money in laying down broken granite to be ground into mud, an alteration was most necessary. The efficient condition of street carriageways is essentially a ratepay- ers' question, and the unprecedented adoption of wood as a paving mate- rial in substitutions of macadam, proves that several of the metropolitan vestries and other authorities have taken a new departure, and apparently a step in the right direction. In expressing this opinion it will be readily un- derstood that the author in no way desires to pass over the respective mer- its of granite, asphalt, or bituminous concrete pavements, and of roadways formed with broken granite, flints, or gravel, as they are undoubtedly suitable for certain localities, and in many cases are economical as compared with wood. While therefore it is asserted that a properly constructed wood pave- ment possesses the advantages of noiselessness, surface elasticity, safety, and cleanliness, and is pre-eminently suitable and economical for business and residential thoroughfares having a high traffic standard, it should not be forgotten that in the case of narrow business streets leading out of main thoroughfares, wood pavement might be unsuitable, as by reason of the un- importance of the vehicular traffic, the blocks would probably decay inter- WOOD PAVEMENTS. 23 nally long before they were worn out by the traffic. For such reasons, and from a sanitary point of view, it would appear that asphalt would not only be preferable, but also eminently suitable. Large sums of money were expended during the early years of wood pavement revival, in the acquisition of patent rights of doubtful value, in experimenting thereon, and in foolish contracts. These stages have been surmounted, and the result is that street paving in the West-end has been almost revolutionized within a few years. Wood pavment has been termed a " West-end luxury," and in one sense the assertion is perhaps justifiable, inasmuch as not more than 4.38 per cent, of the wood pavement in London is east of the city, or south of the Thames. Extent and Construction. The superficial area of wood pavement laid in London during the last ten years has been 980,533 square yards, its length 53^ miles, and the cost of its construction, together with subsidiary works, has probably involved an outlay of ^"600,000. It is now possible to drive through wood-paved main thoroughfares for a distance of several miles ; (e.g.') wood pavement is practically continuous from London Bridge, the exception being the eastern part of the Strand, to any of the stations be- tween Chelsea and Uxbridge Road on the West London Railway. Obviously, much valuable experience and data have thus been gained as to the best mode of construction and maintenance, and as the author ventures to think that a paper on wood pavement would be incomplete unless it embraced every detail, however simple, he will endeavor to discuss the various points which arise, with a view to ascertaining whether wood has practically realized the expectation that it would prove to be a safe, con- venient, and economical material for street carriageway pavements. The suitability of ' ' wood as a paving material under heavy traffic " was so fully treated by Mr. Howarth in 1879, that the author thinks it unneces- sary to refer in detail to questions which have reference to the proper growth of wood, the cause and effect of wear and tear, and the method adopted for recording the traffic ; the object being to describe at length the various points of construction which have hitherto been only partially con- sidered, together with particulars of recent modifications. Excavation. The suggestion has been made that macadamized car- riageways might be broken up expeditiously with the aid of explosive mix- tures, but the author would hesitate to try it ; as, however slight the con- cussion and vibration might be, there is little doubt that gas and water mains and services, especially those which have been in existence for a considerable period, would be injured. Practically there is little variation in the method adopted, the main object being to get the work done as quickly as possible. In preparing for the construction of the wood-pavement works in Chelsea, the method of operation consisted in breaking up the macada- mized carriageways by driving steel wedges into and through the consoli- dated layer of broken granite, commonly called mac, at intervals of a few feet. The surface or crust being thus " started," its removal was effected by prizing it upwards in lumps of a square yard or more with stout hand- levers, 6 to 8 feet long, after which it was easily disintegrated. As a rule, a depth of 9 inches of macadam was thus removed prior to the excavation of some five or six inches of foundation. In those instances where the carriageway had previously been paved with granite upon a concrete foundation, as in Oxford Street, it was found unnecessary to disturb the concrete, since by adding about 2 inches thereto, 24 WOOD PAVEMENTS. and floating the surface, a satisfactory foundation was obtained, and con- siderable expenditure avoided. Levels and Contour. When the width of a street is irregular, and the levels of the footways on either side vary considerably, it is sometimes not a little complex to satisfactorily determine the question of level and contour; but when the longitudinal inclination is naturally slight and uniform, the width parallel, and the footways nearly correspond in level, as in Sloane Street, a very simple rule may be observed. The practice of the author has been to first determine the level of the crown or vertex of the carriageway to be paved, and next to set out the levels of the channels, by allowing a rise to the crown equivalent to i inch in 3 feet ( ^) above the mean channel level. By slightly flattening the crown, Fig. i, it will be observed that a contour is obtained which not only renders traffic easy, but is of pleasing appearance, and satisfactory in other points. Whenever practicable, the longitudinal inclinations of the channels should not exceed i in 150, and it is desirable that the minimum depth of curb exposed at the summit of a channel should be 2^ inches, with a maxi- mum depth of 6| inches at a gulley. By the observance of this rule it necessarily follows, that in a tolerably level street the provision of street- gulleys becomes an important item, but the extra cost, about 4 per cent., which their construction entails, is amply repaid, not only by the convenient and uniform appearance of the carriageway, but in the prompt and effectual removal of rain-water from the surface of the pavement. The author sub- mits that this is an element of success in the construction of wood pavement which unfortunately, is too often overlooked. The longitudinal crown-level should be uniformly sustained from street to street whenever practicable, so as to prevent undulations; and it is like- wise important that the crown should be extended transversely at all inter- sections, partly for the sake of appearance, but mainly to obviate the unpleas- ant effect which is caused by driving over a channel. The neglect of this rule is very apparent upon observing the effect of vehicular traffic over the crossings to Rutland Gate and Princess Gate on the south side of the Ken- sington High Road. Foundation. It is satisfactory to note that foundations consisting of single or double planks placed upon a bed of sand have been completely discarded, and that the fallacies of the so-called elastic foundation have given place to a more permanent system. It was only necessary, shortly after a fall of rain, to witness the effect of a vehicle being rapidly driven over a pavement which had been laid on the former system for a period of two or three years, to have ocular demonstration of its utter unworthiness. The series of little fountains of dirty water which have spurted up in the wheel tracks from the open joints would soon have dispelled the hopes of the most ardent believer in the theory ; and the result not only made it inconvenient for pedestrians, but very soon caused the pavement to go to pieces. Although lias-lime concrete has been used as a foundation, it may safely be asserted that 90 per cent, of the existing wood pavement is laid upon Portland cement concrete. The latter, properly prepared, is absolutely impervious, and as a solid and sound foundation is essential for a first-class pavement, the author fails to see that a more suitable material can be sub- stituted. From a variety of causes the strength of the concrete actually used appears to have varied from 5 to 7 parts of Thames ballast to i part WOOD PAVEMENTS. 25 of Portland cement. In the commencement of the Chelsea works the pro- portion was 6 to i ; but it was sox>n found desirable to provide a quicker- setting concrete, to enable the street to be reopened at the earliest possible moment, The exact proportions, as measured out in boxes, subsequently fffj consisted of 33 cubic feet of ballast to 6.4 cubic feet sand, 5 bushels of cement, or about 5# to i. It is almost superfluous to state that too much care cannot be taken to insure the use of none but good cement. With this object in view, numer- 26 WOOD PAVEMENTS. cms samples of the cement supplied for the Chelsea works were tested, the average result of 197 tests by Mr. H. Faija, M. Inst. C. E., showing the strength and quality to be : Weight per imperial striked bushel H5-45 Ibs. Specific gravity 2.98 Fineness (25 gauge-sieve) 4. 18 per cent. (50 " ) 26.91 Tensile strength per square inch at 7 days ... 571 Ibs. 28 " 677 " The full particulars of the tests are given in the Appendix to the Pro- ceedings (Table II.). The ground having been carefully bottomed up, regulated, punned, and when necessary watered, small ridges of concrete, technically called " screeds," were formed to the required levels and contour. The ballast and cement for the concrete were measured out and mixed upon a platform, and twice turned over dry, water being subsequently added by means of a small hose attached to a stand-pipe. Just sufficient water was used to obtain a fair consistency, and as soon as the materials were well incorpo- rated, the concrete was either wheeled or thrown into place, to a minimum depth of 6 inches. To obtain a perfectly smooth and uniform surface, the concrete was floated and " ruled " transversely to the required contour by means of a curved rule, and in four or five days it became sufficiently hard and ready to receive the wood blocks. That an excellent foundation was obtained has been frequently ascer- tained by means of the numerous gas and water trenches which have been made. To break through the concrete necessitates considerable force, and the use of sledge-hammers and steel wedges, and specimens prove that it is perfectly sound and good. The entire cost in situ averaged 2s. ^\d. per square yard, an amount which compares favorably with other concretes ; and if time were not so important an element in street closing, it might have been executed at a cheaper rate by decreasing the proportion of cement. The cost per square yard is made up of the following items viz. : s. d. o. 166 cubic yard Thames ballast, at 3 s. ^d. o 6| 0.74 bushel Portland cement, including extra for facing, at is. n.d. i 5 Labor in measuring, mixing, wheeling, laying and ruling. . . o 4 Total per square yard 2 3-| In the concrete foundation for Fulham Road a considerable quantity of the old broken granite was screened and mixed with Thames ballast, with a view to practically testing the assertion that an equally serviceable but cheaper concrete could thus be obtained. A similar system has been some- what largely adopted in other metropolitan districts, and notwithstanding that a saving of about ^d. per square yard was effected in the Fulham Road pavement, the author is not encouraged to view the practice favorably, and does not propose to revert to it in future works. He ventures to assert that not only is the old granite of greater value for street repairs in less import- ant thoroughfares, but that consequent upon its dirty condition, the efficacy of the cement is somewhat impaired ; that the concrete so formed is not so WOOD PAVEMENTS. 2^ homogeneous as pure ballast concrete, and that it will eventually prove to be less durable than the latter. In support of this view it was recently ascertained by a sample taken up from Fulham Road that such concrete is undoubtedly of inferior quality, and the labor exerted in breaking through it was remarkably small as compared with the former material. Blocks. The best form and material for wood-pavement foundation having been ascertained, a question of the utmost importance arises namely, which of the various kinds of wood available is the most durable and economical? Until this question has been satisfactorily answered it cannot be maintained that the difficulty has been surmounted ; in fact, to the absence of reliable information thereon, it is undoubtedly possible to trace the cause of many wood pavements becoming prematurely ' ' worn out " after four or five years' wear. Many theories have been asserted as to the merits of various woods, and a large number of the latter have received a practical test, among them being Baltic and Dantzic fir, pitch pine, spruce, beech, larch, oak, elm, and ash. The shape of the blocks has received no little attention, inasmuch as under various systems they have been cut into rectangular, oblique, hexagonal, octagonal, square, and other forms, and of varying dimensions. Considerable diversity of practice has also existed with regard to the con- dition in which wood has been laid, some blocks having been laid in the natural state of the wood, whilst others have either been "dipped " in creo- sote oil, or " dressed" with pitch, and in a few instances they have been properly creosoted. Within the last six or seven years the greater portion of the wood 'pavement laid in the metropolis has consisted of rectangular blocks of Swedish yellow deal, or red deal, or pitch pine, but it cannot be denied that thousands of blocks of an inferior nature have also been laid, after being subjected to the process of " dipping " or " pickling." Prior to adopting wood pavement in Chelsea, the author inspected nearly the whole of the various systems then laid in London (February, 1879), and gave their respective merits every consideration, the outcome thereof being that a plain and substantial system was considered the most desirable. The blocks found most suitable, and of which there is an abun- dant supply, were those cut from Swedish yellow_ deals (Gothenburg thirds), \ and if blocks cut from close and evenly grained, well-seasoned, and thor- oughly bright and sound deals of that description were always used, the author thinks that the} 7 would not fail to give satisfaction. In the construc- tion of wood pavement, it is of the greatest importance that constant super- vision should be exercised with a view to insuring the rejection of improper blocks, or blocks which possess even a suspicion of being sappy, knotty, badly cut, or otherwise unsound, or which have been cut of dead wood, or wood which has been stacked in dock for too long a period. If this system is faithfully carried out, it is doubtful whether there is at present any better wood in the market, of which sufficient quantities can be promptly obtained, and which so satisfactorily stands the wear and tear of traffic and the changes of atmosphere and climate, than Swedish yellow deal, when laid in its natural state. The result of heavy traffic upon various kinds of wood unquestionably demonstrates that of hard woods pitch-pine takes a high place. The price, however, is considerably in advance of fir, and the irregular sizes of the deals creates much difficulty ; but if a satisfactory supply from South Amer- ica in prime condition could always be relied upon, it would no doubt be 28 WOOD PAVEMENTS. largely adopted. A section comprising 756 square yards was laid with pitch-pine blocks in King's Road, four and a half years since, as an experi- ment, and the ascertained depth of the annual vertical wear of the wood during that period, as will be seen by Table III. in the Appendix, is 0.055 inch only. Experience proves that its abrasive wear is better than yellow deal, and, as a rule, it drys quicker and is cleaner ; and although pitch-pine takes the best position as regards vertical wear, its extreme hardness may be considered a drawback. This is especially noticeable in the case of rapid traffic, when the wheels of vehicles have lost the rolling motion and strike the surface with great force. It is then that the smallness of the elasticity attached to pitch-pine becomes apparent, by a jarring, bumping motion, which is far from agreeable. Dantzic fir is durable, but would probably be attended with inconven- ience and waste in converting the balks into ordinary-sized paving blocks. Neither elm nor oak blocks would withstand the atmospheric changes to which street surfaces are exposed. Larch would probably take a high posi- tion as a street-paving material on account of its hardness and durability, but the available supply is apparently too limited to permit its extensive adoption. There is little doubt that American spruce has been laid in Lon- don streets under certain conditions, but such wood cannot be regarded as suitable or durable. Preparatory Treatment of the Blocks. A brief reference has already been made to the preparatory treatment which blocks have received. In many instances they have been subjected to the process of being "dipped " in a mixture of creosote oil and other ingredients, while in a few instances they have been creosoted or mineralized, but at least one-third have been laid in a plain or natural state. The author has little faith in the ordinary " dipping " process as a means of preserving the wood ; and upon severing " dipped " blocks which have been laid for two or three years, it will be found that a mere external discoloration only exists. Indeed it is difficult to ascertain the nature of the merit which the process is supposed to possess, and there may even be truth in the assertion that it is worse than useless, as unfortu- nately, unscrupulous persons have taken advantage of it as a means of covering up the shortcomings of defective or inferior blocks. A great deal has been written as to the value of creosoted blocks, and, by way of experiment, a short section upon this system was also laid in King's Road, the blocks creosoted being selected yellow deal. They were subjected to Bethell's patent process, 7 pounds of hot creosote oil per cubic foot, equal to 10.66 blocks, being injected ; and the ascertained depth of annual wear averages 0.139 inch against 0.055 inch for pitch-pine, and 0.144 inch for plain yellow deal. The creosoted blocks when taken up for exam- ination were moist internally, and came up easily, whereas the plain blocks and the pitch-pine blocks required considerable force to remove them. The author has invariably noticed that the creosoted section is less clean than any other, and he certainly doubts the wisdom of a system which is not only 20 per cent, more costly, but to a certain extent closes the fibres of the wood, and tends to produce premature internal decay. When the latter sets up, it will very soon be found that the traffic causes the fibres to spread, which is quickly followed by the complete destruction of the wood. There can be little doubt that the reputation of wood pavement has seriously suffered on account of the use of unsound and inferior wood. This WOOD PAVEMENTS. 29 may be traced to several causes, either the acceptance of extremely low tenders from inexperienced persons, want of sound judgment in selecting the deals, carelessness, insufficient supervision, especially when the work is hurriedly done, or downright neglect. The experience of the author is, that even with fairly good supervision it is possible for defective blocks to be laid, and it cannot therefore be surprising that unsound wood is used when carelessness, indifference, or neglect is exhibited. As an instance of the success of close supervision, the short section of wood pavement at the extreme north end of Sloane Street may be mentioned. The ascertained traffic, which consists in a great measure of carriages and cabs, is equal to 371 tons per yard width per day, or upwards of 100,000 tons per annum ; and although the wood has been laid for four and a half years, the blocks have only worn f-inch, or 0.083 inch per annum, and the surface is in excel- lent condition. It cannot, therefore, be too strongly urged that street authorities should not only invariably pay a fair price for work, but should provide ample and competent supervision, if they desire to prevent wood pavement from being brought into disrepute. Size of the Blocks. There is little variation in the dimensions of the blocks, the general size being 9 inches long, 6 inches deep, and 3 inches wide. The lengths have frequently varied from 8 inches to n inches, in several instances the depth has varied from 5 inches to 7 inches, but the width, 3 inches, has almost been universally adhered to, it being apparently the best size for foot-hold, and most convenient to procure. Upon measuring blocks supplied by timber merchants, it will frequently be found that the depth is a trifle short of the specified dimensions ; for instance, a 6-inch block seldom exceeds sf inch, it being understood to be the custom of the trade to make an allowance for the thickness of the saw-cut. The question has often been raised whether 7-inch blocks on the one hand or 5-inch on the other, would not be more economical than 6-inch ; and although there is very little experience thereon, the subject will be alluded to under the heading of durability. Laying, 'Jointing, and Completion. Great diversity of practice has existed in the mode of laying and jointing, and a great deal of money has been lost in the acquisition of patented inventions. Under some of the latter systems the blocks were laid on boards upon a foundation of sand, in others the blocks were laid upon a layer of asphalt, or upon tarred felt placed upon a concrete foundation. Blocks have been laid in transverse courses, and under Lloyd's " keyed " system, diagonally. Various modes of jointing have been adopted, technically known as mastic, semi-mastic, cement, lime, or felt, the latter being a close joint, whilst the former varied from \ inch to i inch in width. In the Chelsea pavements the dimensions of the blocks were 3 inches by 9 inches by 6 inches, 40.5 being required for each square yard, and they were laid upon the concrete in their natural state, with the fibres vertical, and with intervening spaces f-inch wide, which were filled with cement grout. The surface of the concrete having become hard and smooth, the method of operating consisted in laying two longitudinal courses of blocks next to the curb to form the channels, and filling in with straight courses transversely, the ends of the blocks being in contact. At the intersections of streets the courses were laid V-shape, so as to insure the traffic passing over the blocks at an angle of 90, or as nearly as possible thereto (Fig. 2). In laying the blocks the joint was kept parallel by means of three cast-iron 30 WOOD PAVEMENTS. studs fixed in each block (Figs. 3 and 4), which materially assisted in keep- ing the pavement firm and steady until the grouting had thoroughly set. By the use of studs instead of wooden strips or laths, it is certain that the blocks are much less liable to become displaced while the work is setting, and in practice a uniform width of joint is more easily secured. The grout was composed of three parts of Thames sand to one part of Portland cement, the materials being measured in boxes and mixed to a proper consistency, in a large movable grout-truck. The grout having been swept out of the truck on to the surface of the wood, was swept backwards and forwards until every joint was properly filled. The prime cost of this work, labor and materials, amounted to 5^. per square yard. Top-dressing. Before permitting vehicular traffic to pass over new work, it is desirable to "top-dress" the surface of the wood with a fine gritty material. This is usually done by spreading a thin coating of very small stones, as screened from Thames ballast, sand, or shingle, over the entire surface, and leaving it to be crushed and ground into the fibres of the wood by the traffic, until it has ceased to be gritty. The cost of this work for the Chelsea pavements amounted to 2.d. per square yard for materials and labor. Whenever practicable, all traffic should be excluded from a newly -laid pavement for at least a week after completion, but there is an obvious difficulty in the enforcement of this rule, whenever a street is too narrow to allow the works to be carried out in half-widths at a time. The expansion of wood is a question demanding consideration in carry- ing out such works. In unprepared blocks this is specially necessary, and in proportion to the width of the street so is it desirable to leave a space next the footways, varying from one to two inches in width. The actual condition of the wood and the state of the atmosphere at the time of laying exercise a material influence on the width of the margins thus left. Another mode is by omitting to grout the channels for a week or longer period after the other portions have been completed ; and another by pav- ing nearly up to the curb, and afterwards taking out the nearest course so soon as expansion sets up. In any case, it is necessary to temporarily fill up the margin with sand or other suitable material, which can be raked out from time to time until expansion ceases, which generally occurs in the course of twelve to eighteen months from completion. In the Chelsea works it was then found desirable to rake out the temporary filling, and where any space was left, to fill in with cement grout, the surface being carefully pointed in cement. This work effectually renders the channels impervious to water, and tends to prevent premature decay, and was executed at a cost equal to o.86 Co.'s Pavement. This plain system of paving has been laid in various parts of the metropolis, particularly in the city, St. Giles, St. Marylebone, St. Pancras, and Kensington. In Princess Street, Cavendish Square, blocks which were laid in September, 1874, are still in existence. Kensington High Street. In May, 1877, a section was laid near the Vestry Hall, at a cost of 14^. per square yard, with a three years' free main- tenance. Six-inch blocks were laid in their natural state with a ^-inch joint of lime grout. The present depth of the blocks is stated to be 3 inches, the annual average wear therefore being 0.440 inch. The surface shows considerable wear, and after rain water is retained at those points where it has worn below the channel-level. The latter evil is possibly to be attributed 38 WOOD PAVEMENTS. to the very slight rounding, one inch in four feet, to which it was laid. The blocks are to be renewed in October next, when the life of the wood will have been seven and a half years. Fulham Road, Sydney Street to Arthur Street. This section was paved in July, 1878, at a cost of 145. per square yard, and in other respects was similar to the last-mentioned pavement. The surface is considerably worn, and the form of joint not only retains dirt but tends to round the blocks, the average depth of which is 4f inches, or equal to an annual average wear of wood of 0.242 inch. The pavement will probably be relaid in 1885, when its life will have been seven years. A large area of " plain " wood pavement has been laid in Kensington by Messrs. Nowell & Robson, who paved Kensington Road, Fulham Road, Uxbridge Road, and High Street, Notting Hill. The last-mentioned street was carried out in December, 1878, at a cost of i2s. bd. per square yard, with a three years free maintenance. The lime-joint gave much trouble shortly after the work was completed, and in places it may be observed that it has allowed dirt to accumulate. The average wear is equal to 0.218 inch per annum. In other metropolitan districts besides Chelsea the local authorities have successfully laid a plain system of wood pavement by means of their own staff of workmen, particularly in St. Marylebone and Paddington. The credit of introducing this method is due to the St. Marylebone Vestry, whose first work consisted in paving the portion of Oxford Street east of Regent Circus, in October, 1878. The blocks were laid upon an existing concrete founda- tion, and the work cost 8s. $\d. per square yard, exclusive of the removal of the old stones. The blocks were repaired in 1882, 1883, and in 1884, at an approximate cost of bd. per square yard. Plain yellow deal blocks, 6 inches deep, were adopted, with a cement joint \ inch wide, and they have worn to an average depth of 3.30 inches, but in some parts of the street the thick- ness is i^ inch only. The surface shows considerable wear, and is uneven in places, the wood being so remarkably thin near the rests that it is a mere crust. The probable life of the wood is six and a half years. The average annual wear is 0.475 inch, and if reduced to the traffic standard it is equal to 0.306 inch. The heavy rate of wear is probably owing to the width of the joint, the author having taken up a piece of grout inch thick. This irregu- larity would have been avoided by the use of iron studs instead of tempor- ary strips or laths. A large area was similarly laid in Edgeware Road in October, 1880, and at the same cost. The surface is good ; the annual wear is 0.198 inch, and if reduced to the traffic standard it amounts to 0.254 inch. The Paddington Vestry have laid 125,232 square yards in various streets. Praed Street was paved in July, 1879, with 6-inch plain yellow deal blocks, at a cost of los. id. per yard, and the surface is in a fairly good state. At the eastern end the blocks have been repaired on several occasions, the present depth of wood in the centre part being 4 to 4| inches. Generally speaking, the plain system appears to have given satisfaction, but the mode of jointing with lias-lime grout, or a wider joint than f-inch, cannot be recommended. Upon inspecting the lime-joint after a few years' wear, it may be ascertained that it wears below the surface, that dirt accumulates in the joints, and that the blocks have either become rounded or the top edges " burred," to such an extent that the surface has become bumpy. The lime-joint gave trouble when newly laid in Notting Hill in WOOD PAVEMENTS. 39 December, 1878, as after a sharp frost the grout, so to speak, " spewed " up, the rain filled the joint, and considerable sections of the pavement were literally afloat until the defects were remedied. A system of blocking, which the author considers objectionable, is that by which the blocks of a new pavement are laid upon fresh unset cement floating, and, as the grouting is proceeded with, the blocks rammed with a "pavior's" rammer, so as to obtain a smooth surface. Under this process there is a probability of the blocks being injured or split, apart from which it is found that when the time arrives for renewing the wood, the surface of the concrete contains a series of indentations instead of being smooth and even. The difficulty may of course be surmounted by chipping off the projecting parts and refloating the surface, but the repaving cannot be so expeditiously or economically carried out. The result of the author's experience and investigation induces him to submit (i) that.the surface of the concrete foundation should be per- fectly smooth and fully set before the blocking is proceeded with, and (2) that a carefully-made cement-joint f-inch wide will not only be found sim- ple and water-tight, but will prove as durable as the wood itself. Cost. With the exception of a small area, the whole of the wood pave- ment in Chelsea, about 50,000 square yards, has been laid by the Board's own staff. The estimated cost of the pavements in King's Road and Sloane Street was us. ^d. per square yard,* but, as previously stated, the actual cost amounted to los. 6d. per square yard, exclusive of ^120 spent in the before-mentioned experiments. The pavement in Fulham Road cost los. ^d. per square yard, the difference being partially attributable to the fact that a portion of the old broken granite was used in the concrete foundation in lieu of ballast. The details of the cost per square yard, are as follows, viz.: ITEM. 3*1333 Y ds - in Sloane Street and King's Road in 1879. 'QjSTS yards in Fulham Road in 1881. Labor in breaking up macadam surface and excavating d. II OO d. II OO Cartage of old materials, including shoot 9.04 Q 80 Portland cement for concrete and grout Thames ballast and sand for concrete, grout, and top dressing . . 20.02 8.56 I .17 5 80 Blocks 58.66 60.82 Studs 1.58 1.48 Labor in bottoming up and leveling, pre- paring and laying concrete, fixing stud in, wheeling and laying blocks, grouting, top dressing, watching and sundries I -I ACi 14. 12 Labor and materials in permanently filling in margins o 86 o 90 Sundries plant, tools, superintendence, testing cement, oil, repairs, etc 2 Q2 i 8s Total 126 OQ 122 Q4. NOTE No allowance is made for value of the paving stones and broken granite taken up and re-used in other parts of the district, the minimum value of which amounted to ,2,050, or about is. per square yard. Minutes of Proceedings Inst. C. E., vol. Iviii, p. 75. 40 WOOD PAVEMENTS. The variation in the prices paid for wood pavement in various parts of the metropolis has been somewhat remarkable, the maximum cost per square yard for laying a pavement and concrete foundation with entirely new materials having amounted to iSs. 6d., and the minimum to 10^. bd, Owing presumably to competition and to the experience which has been gained, together with increased facilities, the cost has gradually been reduced to reasonable limits, as compared with the charges made eight or nine years since. Maintenance. However excellently a street carriageway pavement may have been constructed, its condition will soon become unsatisfactory unless its maintenance receives proper supervision. Good management implies not only that repairs shall be promptly and efficiently executed, but that the services of cleansing, watering, and sanding must be properly carried out ; in short, the essentials of proper management are to be found in the judicious application of the scraper and broom, of water, and of grit, and in the immediate removal of defective blocks. The reinstatement of gas, water, and drainage-trenches must be classed under the first heading ; and although an apparently small matter, yet, from the frequency of such openings, so serious an interference with the street surface is created that in the course of a few years surface uniformity cannot be maintained unless this work is very carefully executed, and ample time allowed to elapse before the traffic is allowed to pass over the work. After a pavement has been laid for three years the existence of defective blocks becomes appar- ent, as by this time, the first effect of compression having ceased, the fibres of such blocks begin to yield under traffic pressure, with the result that slight surface depressions are formed. When this happens a bumping motion is created, and as the wheels then strike upon the edges of the adjoining blocks it is obvious that the surface must become irregular; and depressions or hollows a foot square or more are soon formed, which, unless promptly remedied, materially spoil the surface. ,. To avoid slipperiness and to insure many of the advantages claimed for wood pavement, it is essential that a thorough and systematic service of cleansing must be carried out, especially where macadam pave- ments are contiguous to wood, as in damp weather a considerable amount of mud is imported from them. In connection with the wood pavement in Chelsea there is a regular street orderly ser- vice, by which horse-droppings are removed and deposited in bins. In addition thereto the wood pavements are washed once or twice a week, and are cleansed daily either by horse-sweeping machines or by hand labor. In the absence of heavy rains mere sweeping fails to keep wood pavement clean, and washing then becomes essential. To effect this water-vans are sent out before midnight, and the surface is so thoroughly soaked that, by the time the sweeping machines commence to work at 3 A. M., the dirt is easily removed, the entire operation being concluded in the forenoon. The ascertained cost of this service, including labor and horse hire in washing and sweeping, street orderly work, and collection and removal of the sweepings, amounts to $\d. per square yard per annum, as against \\d. per square yard for macadam previous to the substitution of wood. It has been asserted upon good authority that the cost of cleansing wood pavement is very trivial ; this is slightly misleading, the proportions being approximately : Macadam i.oo Wood . . 0.41 WOOD PAVEMENTS. 4! Theoretically, the amount of mud created upon the surface of wood, as also in the case of asphalt, should be almost nil ; but practically the author finds that some 2,700 cartloads are annually removed from a length of about three miles in Chelsea. Therefore, after making every allowance for the conversion into mud of 350 loads of sand placed on the wood when slip- pery, it is obvious that a great portion of the mud is imported from the adjacent macadam. The plentiful application of water prior to the work of cleansing is most beneficial, both in preventing dust, and, from a sanitary point of view, in removing the cause of obnoxious smells ; but as the metropolitan water- supply is not yet in the hands of the ratepayers, its use for this purpose is materially restricted. The author ventures to assert that the system of cleansing thus described is amply sufficient to obviate slippery surfaces caused by the accumulation of greasy mud, and that the summer watering may be so carried out that a minimum wetting will suffice to keep down the dust. Letters have recently appeared in the Times with reference to the watering and cleansing of wood pavements, in which it has been strongly urged that such pavements should not be watered at all. When it is considered in what an unskillful manner street-watering is sometimes done, and that, owing to the stupidity or carelessness of carmen, considerable danger to locomo- tion is caused by overwatering a dirty pavement, there may be some justifi- cation for the contention. Doubtless horses travel better on dry wood pave- ment than on a watered surface, but in the absence of rain, watering is an absolute necessity for keeping down fine dust, more especially upon a hot windy day, when at least five or six wettings are required. Watering is also necessary for the preservation of the wood itself, as without water it would be materially injured by abrasion under such conditions. It is also questionable whether the very fine dust which must be given off under a non- watering system, would not become so serious as to be injurious to health and promote disease of the eye ; but apart from this, the nuisance from the heat and dust combined would become intolerable. In continuous damp and foggy weather and on frosty nights wood pavement is especially liable to become slippery ; therefore, to insure a safe foot-hold for horses, its surface should be covered with a thin layer of Thames sand or grit. In Chelsea it has been found that this operation can be more expeditiously and evenly carried out by horse-machines known as " sand-distributors " than by manual labor alone. Night gangs have been organized, and, according to the conditions of the weather, the machines are sent out either at night or early in the morning ; in the latter case the whole of the wood is sanded and made fit for traffic by 8 o'clock. The operation is beneficial to the wood itself, and might be advantageously carried out at other times, because the grit becomes so well worked into the ends or fibres of the blocks that it not only affords protection to them, but insures a bet- ter foot-hold for horses. The ascertained cost of the sandings does not exceed \d. per square yard per annum. Durability. One of the most important factors in connection with durability is the amount of traffic to which the pavement is sub- jected. As the author has been unable to obtain complete information thereon he has had to rest content with the available figures, and has reluctantly omitted results and comparison of other important streets. Table III. shows (i) the daily traffic weight per yard width ; (2) the depth WOOD PAVEMENTS. of annual wear of wood ; and (3) the annual wear of wood as reduced to a standard of traffic equal to 750 tons per yard width daily, or 235,000 tons per annum, exclusive of Sundays. It is gratifying to remark that there is a growing tendency to make observations and keep records of traffic weight, wear and cost, and it is only by these means that reliable data can be obtained. It is to be hoped, therefore, that both local authorities and wood- pavement companies will institute the desired inquiries, by which means much valuable experience and knowledge will be gained. The comparative annual wear reveals several inconsistencies. For instance, the wear of the asphaltic pavement in Fleet Street, with the maximum traffic weight, or 24th on the list, is but i6th in point of wear, whereas the same system with the i3th and gth traffic weight positions, takes the high places of 24th and 23d in wear. Lloyd's pavement in Regent Street has an 8th traffic-weight position, but is 2oth in wear. The wear of the Improved, of Henson's, and of the plain pitch-pine pavements compares favorably in all cases with the traffic weight. The lesson to be drawn from these figures would appear to be that the III. COMPARATIVE WEAR OF WOOD PAVEMENTS AS REDUCED TO A TRAFFIC STANDARD. SITUATION. SYSTEM. Weight per yard width per day of sixteen hours. Depth of annual wear of wood. Comparative annual wear of wood as reduced to a traffic stan- dard Of 750 tons per yard width per diem. ^fjMfipt Street Asphaltic Tons. Inch. Inch. ,360 ,2 3 6 ,191 ,I6 5 ,164 ,137 ,106 ,000 985 948 808 648 603 584 584 558 558 558 55i 498 468 434 407 279 0.456 0.428 0.191 0.269 0.475 0.484 0.154 0.264 0.329 0.323 O.2OO 0-373 0.157 o. 184 0.198 0.286 0.214 0.089 0.144 0.139 0.055 0.139 O.III 0.065 0.251 0.259 0.120 0.173 0.306 0.319 o 104 0.198 0.250 0.255 0.186 o.43i 0.195 0.236 0.254 0.384 0.288 0.119 0.196 0.209 0.088 0.240 0.204 0.175 Ludgate Hill *Oxford Street . . . *Fleet Street Improved Henson's(east section) . . Henson's *Oxford Street. .. *Oxford Street *Parliament Street *Leadenhall Street * Oxford Street. . . . *Oxford Street. . . . *Leadenhall Street Brompton Road . . King's Road Brompton Road . . *Edgeware Road . *Regent Street . . . *Regent Street . . . King's Road Plain Asphaltic Improved Henson's Henson's (west section) . Henson's (central sec- tion) . . ... Improved Asphaltic Improved Henson's Plain Asphaltic . . Lloyd's Improved (pitch-pine) . . Plain King's Road King's Road Plain (asphalt bed) Plain (pitch-pine) ..... King's Road King's Road Creosoted blocks (mas- tic joint) King's Road Creosoted blocks (lime "joint) . . Sloane Street Plain * Weight of traffic taken from Mr. Howarth's paper in these instances. WOOD PAVEMENTS. 43 asphaltic and Lloyd's systems are not successful ; and the author cannot help regretting that Regent Street should have been paved upon either of these particular systems. The pavement in Parliament Street is stated to have worn inch only in three and a quarter years, but it must not be for- gotten that its real wear has scarcely begun, and that the traffic weight is high. Should its life be eight years (which is extremely doubtful), it would take a higher position, as the annual cost would probably be is. 6d. per square yard. It is interesting to notice that some pavements have exhibited a consid- erable degree of durability and have had a tolerably fair life. In the author's table the pavements and periods under the headings " actual " life relate to accomplished facts, while several under the heading " esti- mated " have already nearly realized the life allotted to them. In other cases the estimate is given after inspection and measurement or inquiry. The number of the pavements is necessarily restricted in consequence of the absence of traffic-weight records. The author inclines to the opinion that it is not desirable to lay blocks of a greater depth than will provide for a life of seven years, as very few pavements retain a good surface after about six years' wear. In the case of the pavements previously described which have attained a greater life than seven years, it is proper to explain that those periods were only insured by the execution of frequent and somewhat costly repairs. For instance, a considerable number of new blocks, of depths varying from 3 inches to 5 inches, according to the extent of wear, had to be inserted in most cases, while in others the old blocks were taken up, reversed and relaid. These operations, however, are very unsatisfactory, both in appear- ance and ultimate result . Experience consequently suggests that if 5-inch blocks were adopted instead of 6-inch, it would be preferable ; and the author favors the opinion that the smaller depth would be found not only sufficient, but more economical and suitable, and would obviate much patch- ing. Five-inch blocks are cheaper by IQS. per thousand, and it is estimated that in the first cost and twice renewal of a pavement which has an annual traffic of 750 tons per yard width, there would be a reduction in cost of is. bat. per square yard in fifteen years, or \\d. per square yard per annum. Even if the average annual wear of 6-inch blocks should prove to be very little, after seven years' wear it will generally be found that the surface is irregular ; but considerable hesitation is always shown before local author- ities order the wood to be renewed, for fear that they may be accused of waste or extravagance in removing blocks which still retain a good depth, although they show a considerably worn and bumpy surface. In short, therefore, 5 -inch blocks would give as good a surface and pavement as 6-inch blocks : there would be less waste of timber in renewal, and on the whole there is little doubt that pavements would be kept in a better condi- tion. Blocks having a depth of 5 inches only have been laid in Oxford Street, Leadenhall Street and Aldersgate Street, and in Kensington a large area has been laid on this system ; and the result so far appears to be satisfactory. The author has obtained numerous specimens of blocks from various streets, and he submits nearly sixty, which have been taken from Regent Street, Pall Mall, Canon Street, Oxford Street, Ludgate Hill, Brompton Road. Praed Street, Sloane Street, King's Road, and Fulham Road. It will be observed that the maximum depth of wood is from King's Road 44 WOOD PAVEMENTS. (pitch-pine), which is sf inches after four and a half years' wear, and that the minimum is from Oxford Street (near Rathbone Place) which is if inches after six years' wear. Wood Pavements on Grades. Obviously there are local matters to be considered in connection with wood pavement, for instance, the effect of traffic in a wood-paved street having a sharp gradient. This has not specially come under the author's notice, except at Ludgate Hill, where the blocks laid in 1877 were removed in February, 1884, having been, it is alleged "kicked out " by horses' shoes, and not fairly worn out by vehicles. The inclination of the carriageway of Ludgate Hill is i in 25. Similar results are noticeable at the Western approach to Hyde Park Corner, at which place the inclin- ation is i in 37. The question of gradient in wood-paved streets is also an important factor in regard to the tractive action of horses and the limit of safety for foot-hold, and it is regrettable that so little experience thereon is extant. In the city the steepest gradient paved with wood is in Ludgate Hill ; in some parts of Piccadilly the inclination is i in 25. It might there- fore be assumed that, so far as actual safety is concerned, a gradient of i in 20 would not be too steep. In Chelsea the main roads are tolerably level, but there is little doubt that the annual wear of the blocks in King's Road (0.144 inch) is greater in consequence of the increased amount of omnibus traffic which has recently taken place, as, owing to a keen competition, omnibuses have been very rapidly driven along the street at times. A con- siderable amount of light traffic has also seriously tried the wood. In Sloane Street the nature of the traffic calls for no particular observation, and the annual wear of the wood (0.065 inch), together with the traffic-standard wear, gives a result which compares favorably and satisfactorily with any other street in London. To insure durability, it may briefly be asserted that next to sound con- struction it is highly important that the number of openings for gas and water services should be limited, and that undue wear and tear can be miti- gated by efficient cleansing and sanding. Neglect of the latter not only creates slipperiness, but is followed by permanent injury to the pavement itself. In support of the author's views, he submits a number of blocks as taken up from various streets in the metropolis. Some are remarkable as specimens of excellent durability, while others exhibit considerable wear, and the very thin ones have created great surprise that a pavement could be held together with blocks so much worn. Cost of Maintenance. The author has frequently been asked whether the wood pavement laid in Chelsea has proved economical as compared with macadam, the answer to which may be found in the following state- ment, which is based upon the assumption that the average life of the wood blocks will be seven years, and which shows that the first cost, repairs, renewals, and cleansing, if spread over a period of twenty years, amounts to is. qd. per square yard, whereas the previous cost of repairing, renewing, and cleansing macadam, but exclusive of first cost, amounted to 2^. lod. per yard. WOOD PAVEMENTS. 45 Estimated Cost of Wood Pavement Per Square Yard in Chelsea, for a Period of Twenty Years. - J- d. First cost o 10 6 Repairs o 06 Renewal of blocks every seven years o 12 8 Interest on loans (at 4 per cent.) o 29 20) i 65 Per annum o i 4 Add cleansing and sanding o o 5 Total o i 9 If the cost be spread over a period of fifteen years only, the figures will be increased to i s. 8f d. per yard per annum for the wood + $d. for cleans- ing, or a total of 2s. \\d. Under the above circumstances it may be fairly assumed that the annual cost of properly constructing, repairing, and renewing wood pave- ment, exclusive of cleansing, which is subjected to a traffic of 500 to 700 tons per yard width per day of sixteen hours, and leaving it in a thoroughly good condition at the expiration of fifteen years, does not exceed is. gd. per square yard ; whereas the average annual cost of repairing and renewing the macadamized carriageways in Sloane Street and King's Road, formerly amounted to is. in/, per square yard, and in Westminster similar repairs cost: s. d. In Parliament Street 2 10 "Whitehall 2 io| " Victoria Street 2 o " Great George Street i 8 No doubt many similar instances might be adduced, in support of the assertion that, as a paving material, wood possesses the advantages of economy, independently of the saving in cleansing. The annual cost per square yard for laying and maintaining wood pavements in various localities, including interest on loans, is given in Table VI. In most instances the actual cost has been supplied, and in the remainder it has been carefully estimated, after making due allowance for efficient and creditable maintenance. The author regrets that he has been unsuccessful in obtaining fuller information as to the cost per square yard relatively to the traffic weight per yard width, but such information as he has obtained he has classified in the following table, and from which certain deductions are drawn. Until local authorities, or those persons directly interested in the question, adopt meas- ures for ascertaining the latter, a considerable amount of theory must necessarily be exercised in deciding the question of cost according to the weight of traffic. 4 6 WOOD PAVEMENTS. DAILY TRAFFIC WEIGHT PER YARD WIDTH OF PAVEMENT. SYSTEM. 400 tons. 500 tons. 750 tons. 1,000 tons. 1,250 tons. Plain yellow deal . s. d. I 4. s. d. s. d. I Q s. d. s. d. i ioi Plain pitch pine i 6 Creosoted yellow deal . . . i 61 I IOT Henson's. . . I Q| i o| 2 O Improved i ii 2 \\ Asphaltic 2 O 2 OT Lloyd's. . . 2 2 The figures undoubtedly give the plain system of pavement the high- est position in an economical point of view, and show the comparative cost of other systems in a manner not hitherto attainable. It is apparent that as the minimum net cost of a soundly constructed and properly maintained wood pavement amounts to i s. gd. per square yard for a traffic of 500, and not exceeding 750, tons per yard width, the absurdity of some of the maintenance contracts which have been entered into is remarkable. On the other hand, a good bargain was made by the Improved Wood Pavement Co. in 1876, when they undertook to lay and maintain a large area in Piccadilly, also upward of 2,000 square yards in King's Road, upon the " deferred payment " system, the rate for Piccadilly being $s. per square yard per annum for a period of fifteen years. The result will con- sequently be that no less than 45^. per square yard will eventually be paid for an expenditure which in all probability will not greatly exceed 30.?. In justice to the authorities, who entered into so costly a contract, it should be stated that in the year 1876 the modern system of wood pavement was in its infancy, and that public bodies were somewhat timid in incurring large outlays thereon ; and as the contract stipulated that payment would cease immediately the contractors failed to efficiently maintain the pavement, it was considered that the risk would be small, as a proportionate amount only would have been paid. Much trouble has been caused by public boards accepting low tenders for first cost, and ridiculously low terms for continuous maintenance, and it has been truly stated on a former occasion by Mr. Burt, that some persons " were running a race to see which could get ruined the fastest." This prophecy has been literally fulfilled, but, unfortunately, as in the case of asphalt and other systems of pavement when improperly undertaken, the consequences had seriously damaged the reputation of wood pavement. Considering that persons enter into contracts to efficiently maintain large areas of pavements with a daily traffic of 600 or 700 tons per yard width, for a period of fifteen years, for the sum of gs. per yard, whereas the net cost in all probability will amount to 13^., it is obvious that either the pave- ments will be insufficiently repaired or renewed, and the reputation of wood injured, or that " a day of reckoning" must come. With the experience already gained, it cannot be too strongly urged that public authorities should look ahead, and not accept a tender merely because it happens to be the lowest. Another matter ought perhaps to be mentioned, although, per- haps, a somewhat invidious one namely, that ample and competent super- WOOD PAVEMENTS. 47 vision should be provided, so that every detail in the execution of the works, especially the rejection of unsound blocks, may receive attention. The operation of inspecting every block is undoubtedly tedious ; for example, in the Chelsea works, where the timber supplied was of fair quality, it was found necessary to separately sort out, reject, and mark about one block in twenty, the rejections being 96,000 out of a total delivery of nearly 2,000,000; and there is little doubt that, owing to the hurry of the work, many blocks VI. ANNUAL COST OF VARIOUS WOOD PAVEMENTS. SYSTEM. SITUATION. Traffic weight per y'd width per diem in tons. Annual cost per sq. y'd for first cost, renew- als, repairs, and inter- est on loans (exclusive of cleansing) if spread over a per'd of 15 y'rs. Plain Sloane Street. . . 27Q s. d. 3l Euston Road 7OO 5i Plain (pitch pine Creosoted blocks lime joint) King's Road 468 407 6 Henson's Oxford Street (C) 948 gf Plain King's Road 551 g? Improved Leadenhall Stre't 808 ol- Asphaltic Strand I,IOO io Plain Edge ware Road 584. IOy M Oxford Street.. 1,164 IO- ' ' (asphaltic bed) . Henson's King's Road . Oxford Street (E) 498 1,191 10; IO^ Oxford Stre't (W) 985 IO^ Creosoted blocks (mastic joint) Asphaltic King's Road Regent Street. . . 434 558 I lOf 2 O Improved . . Aldersgate Stre't 2 O N'th'mberl'd Av. 2 O Asphaltic Fleet Street 1,359 3 ol Henson's (i 1,165 2 I * Improved Oxford Street. . . 985 2 I Asphaltic Brompton Road. 648 2 I Henson's \d. per square yard ; and for the future he estimates it would be on Knightsbridge 35-. per yard.* Cleansing Macadam in Piccadilly costs an average of tod. per square yard per annum. For Knightsbridge it would be two cart- loads of sweepings a day in dry weather, and ten loads in wet weather; and as statistics show wet days for one-half the year, there would be 1,872 loads at 4*. per load, or a cost of iid. per square yard per annum on 8,218 yards. For wood, the estimate is 3^, per square yard. Including cleansing, water, maintenance, and a proportional part of first cost and interest divided over fifteen years, he estimates a sav- ing in the use of wood over macadam of about is. per yard per year. The wood pavements can be contracted for at 3.?. per square yard for first cost and maintenance for fifteen years. WOOD PAVEMENTS IN PARIS.f In continuation of the series of pavement articles that we have published in previous issues, we have prepared a description of the present standard practice of paving with wood and asphalt in Paris. * There seems to be a discrepancy in this estimate as compared with a subsequent report to be quoted from hereafter, showing a much greater quantity of mud removed from Piccadilly, and a much greater saving than is shown by the estimate here made for Knightsbridge, but it is given as reported. fxvii, 281. WOOD PAVEMENTS. 91 The regulations and specifications for the work are translated from the Annales des Fonts et Chaussees, and will follow this intro- ductory description of the conditions and methods of work in 1883, when the first satisfactory trial of wooden blocks was made. We abstract below the paper of M. A. Laurent, Ingenieur des Fonts et Chaussees, published in the Genie Civil, at that time. Numerous failures in the use of wooden pavements on public roads has discredited them in Paris, but their rapid extension and success in other countries, particularly in London, under very heavy traffic, has compelled the attention of the municipal authorities. Objections to Macadam. A new study of this mode of surfacing was demanded, not only on account of the hindrance occasioned by the constant reballasting of the more frequented macadamized public ways, and by their frequent renewals, with the attendant mud, dust and increased resistance to traction and restriction of traffic, but also by the quantities of waste material stopping the drains and endangering public health. The problem of replacing these macadamized pavements in the great thoroughfares involved its effect upon the sewers. First Contracts. The Administration favorably received the proposals of the London Wood Pavement Company, who have suc- cessively obtained the contracts for more and more important work. In 1 88 1 they paved their first section on a small portion of the Boulevard Poissonniere and the Rue Montmartre; in 1882, and early in 1883, all the roadway of the Avenue des Champs-Elysees, from the Place de la Concorde to and including the Rond-Point, had been relaid with wooden pavement, and the Municipal Council has now just accepted their proposition to pave a large portion of six of the most important boulevards, the company guaranteeing its work for a long period, and the city in turn permitting them great liberty in the execution of the work by English methods. The Process. The process of the Improved Wood Pavement Company essentially consists in the construction, on a perfectly rigid foundation, of an impermeable surface of wooden paving blocks (pav6s) thoroughly solidified. The resistance of the pavement to the action of the wheels depends almost entirely on the foundation, the wood being intended solely for a covering to protect this foun- dation, and to secure, by its elasticity and the perfect uniformity of its upper surface, the smoothest possible rolling of vehicles. Rigidity of foundation, solidity of blocks, and impermeability of the surface are the three points this system aims to secure. (i) Foundation. This consists of a bed of Portland cement betono.i5 m. (6 inches) thick, with top coat of cement mortar about o.oi m. (|-inch) thick. The beton is thus proportioned : A 92 WOOD PAVEMENTS. mixture of about one-third sand and two-thirds gravel is put in a bottomless box containing half a cubic meter (0.65) cubic yards), and after the removal of the box 100 kilograms (220 pounds) of cement are emptied on the heap. This is in the proportion, by volume, of about one-seventh as much cement as there is sand and gravel, since 1,400 kilos is the mean weight of a cubic meter of good Portland cement heaped loosely. The sand was dredged from the bed of the Seine and the gravel taken from pits on the seashore. The cement was furnished by the manufactory of Demarle & Lonquety, of Boulogne-Sur-Mer. The paving-blocks should have a uniform thickness and not be laid on the bed of beton until after it has set, in order to exactly pre- serve the curvature of the surface of the beton required for the con- vexity of the roadway. In the Avenue des Champs Elysees the con- vexity was o.42m. (i6 inches) in a width of 27m. (87 feet 7 inches), which represents a mean transverse slope of a little more than 3 in 100. This convexity, though less than first proposed by the company, appears to be a little excessive, and it seems that for a road under satisfactory drainage conditions the convexity might be diminished; 0.42111. is only a mean convexity, for, on account of the small longi- tudinal slope of the avenue, the grade of the gutters is not parallel to the grade of the street, but presents a series of short slopes from the hydrants to the sewer openings, consequently the convexity varies from 0.39111. (15^ inches) at the hydrants to 0.45111. (17^ inches) at the sewers. To exactly regulate the surface of the beton a series of trans- verse profiles were defined by stakes leveled to the grade of the top of the bed. Along each profile a strip of stiff beton was laid. The top of this beton was carefully leveled and smoothed and received a guide rule, laid flat, whose thickness exactly corresponded with that of the beton coating. This series of rules thus formed a set of guides close together, between which it was easy, with large straight edges, to level the beton to the required surface. The first leveling could never be more than approximate, the surface of the beton nat- urally remaining somewhat rough. The exact level required, as fixed by the tops of the rules, was secured by the top coat of cement-mortar which filled the spaces between the pebbles and made an exact sur- face. This mortar was first composed of 200 kilos of cement to a cubic meter of sand (336 pounds to the cubic yard), but this propor- tion proving too small it was increased to 300 kilos. It was always mixed with a great excess of water so as to penetrate the interstices of the gravel. (2) Paving. The covering is formed of small uniform blocks, of red northern fir, 0.15111. (6 inches) high, o.22m. (8} inches) long WOOD PAVEMENTS. 93 and o.oSm. (3^ inches) wide. These are set close lengthwise, with joints, transverse to the street, of about one centimeter (f-inch). The blocks are sent, ready for use, from England, where they were cut from planks of the ordinary size, o.oSm. thick by 0.2 2m. wide. The third dimension, taken in the length of the plank, forms the height of the block, so that in position the fibres of the wood are placed upright. The blocks are superficially creosoted after being cut. When the foundation has set, two or three days after being laid, the blocks are set by the pavers. Owing to the light weight of the blocks the work of paving is very rapid. Between crossings the blocks are set in rows perpendicular to the axis of the street, with their longitudinal joints staggered exactly half the length of a block. The methods used at crossings to avoid a continuous joint parallel to the traffic are analogous to those used in stone paving. Special precautions should be taken to insure exact spacing and regularity of the rows. Before commencing a new row a strip, whose thick- ness is exactly that of the required joint, is set edgewise in contact with the last row and the paver has only to set the adjacent blocks in contact with it. The blocks do not at first adhere to the foundation and are easily displaced after the removal of the strips, and to maintain them in place, as soon as the strips are taken out a small quantity of bitu- men is poured in the joints. This liquid material fills the small spaces that may exist under the blocks and partially fills the joints, and in solidifying effectually seals the blocks. The joints are then filled by a thin grouting of neat Portland cement, distributed by the aid of a broom. This should be done at least twice to insure perfect filling and the essential im- permeability. The pavement cannot be opened for traffic until after the cement in the joints has completely set, for which a delay of 4 or 5 days is considered necessary. During this interval the last operation is performed viz., spreading a thin layer of dry sharp sand over the surface. The company claims that this dressing, crushed under the action of the wheels, incrusts itself in the wood and lends resistance to the wearing surface. It seems more probable that this coating is simply to protect the fresh mortar from the direct action of the wheels, for it can be maintained but a very short time on a traveled road, and is soon transformed into a disagreeable greasy mud. Avenue des Champs Elystes. The paving of the Avenue des Champs Elysees was divided into two parts, in the first of which the city removed the old pavement, and in the second jhis work was done by the company under a special contract. 94 WOOD PAVEMENTS. For the first division, the removal of the old pavement was com- menced October 16, 1882 ; first beton laid October 20 ; paving com- menced October 24, and the first portion of the roadway opened November 2 ; the removal of old paving completed December 10 ; the last beton laid December 12; the surfacing finished December 14; the paving finished December 18, and the road completely opened December 22. The total duration of work for 14,000 sq. m. (18,340 square yards) of surface was 67 days, corresponding to an average progress of 210 sq. m. (252 square yards) per diem. Considerable time is necessary for the various successive operations, but only sufficient space should be maintained between them to prevent crowding and interference between the workmen. These operations in the Avenue des Champs Elysees have always required 15 days, and though this time might be somewhat reduced by decreasing the length of a section opened up, it is not safe to estimate for any shorter time ; 15 days therefore constitutes the period necessary to put the work in operation and complete one section, and this time should be deducted from the total time to find the true daily advance, which would become in the above instance 270 sq. m. (324 cubic yards). The second part of the work commenced March 29, 1883, and required 62 days for a surface of about 13,000 sq. m. (17,030 square yards), giving the same mean daily rate of 210 sq. m. The actual advance was 275 sq. m. (330 square yards) per diem, and would have been much more if it had not been delayed by lack of mate- rials. The conditions were much more favorable on account of the season, the absence of hindrances attending the commencement of work, and because the removal of the old pavement was done by the company, so that but for lack of materials an advance of 300 sq. m. (360 square yards) would have been made daily. SPECIFICATIONS.* The following is a translation of the specifications and the principal instructions and conditions embodied in the " Direction of work in the service of the public way," issued to contractors in 1886 by the Prefecture of the Department of the Seine for Roads and Bridges. CHAPTER i. Regarding Contracts. ART. i. The plan com- prises the transformation to a wood pavement of about 34,500 square meters, (378,165 square feet) of the existing road on the upper part of the Avenue Champs Elysees, and before the principal entrance of the Palace of Industry, the city reserving the right to construct the stone pavement under the carriage stations. *xviii, 1 6. WOOD PAVEMENTS. 95 ARTICLE 2. The contract Vill be an unrestricted one to which only joint stock companies having their headquarters in Paris will be admitted, and they must conduct all their operations, unless it be the purchase of new material, in French territory, and present satis- factory financial guarantees for the performance of their obligations. At least one month before the award of the contract the com- petitors must file with the Administration the necessary securities, a copy of their charter, a detailed statement of the method proposed for the preparation of the paving blocks and treatment of the joints, and specimens of the paving blocks and asphalt intended for filling of the joints. ARTICLE 3. During the continuation of his bonds the con- tractor cannot, without the express authorization of the Administra- tion, in any wise modify the process described, nor use any materials not rigidly conformable to the specimens exhibited. CHAPTER II. Foundation and Paving. ART. 4. The demolition of existing roads and removal of old material shall be executed by the contractors for the new work. ARTICLES 5, 6 and 7 provide for the removal and storage of the classified materials from the old roads. ARTICLE 8. The contractor must do all necessary grading and prepare the road-bed in prescribed form, and must immediately remove the excavated material to the public dumping grounds. ARTICLE 9. If the removal of the total thickness of the old road makes a. filling necessary to attain grade for the bottom of the new road, no other material can be used than the ballast of the old road, which must be free from earth, turf, etc., and carefully laid and arranged. ARTICLE 10. Foundation. The road-bed having been prepared and accurately surfaced, the contractor must lay a bed of Portland cement beton, at least 0.1501. (5j-inch) thick, which will cover all the space between the borders of the sidewalks. The Administration reserves the privilege of requiring, without extra payment, a thick- ness of o.2om. (8 inches) where the soil is bad or the sewers have been recently placed. All the materials used in the composition of the beton must be of the standard quality and inspected by the engineer before using. The beton will be composed of at least 200 kilos (441 pounds) of Portland cement to one cubic metre (35.3 cu. feet) of a mixture two-thirds pebbles and one-third sand. The contractor will proportion the materials under control of the Administration by means of standard boxes approved by the engineer. The contractor may mix the materials by any convenient pro- cess, but the mixture must be first intimately effected in a perfectl 96 WOOD PAVEMENTS. dry state, and the beton must be perfectly homogenous, so that no pebbles can be distinguished in the mass that are not completely enveloped in mortar. Sufficient water must be used for the employ- ment of the beton in a fluid state. The material will not be emptied directly on the earth, but on a portion of beton already in place, whence it can gently flow to the place it is to occupy, where it will be lightly rammed with a shovel. The surface of the beton must be perfectly smoothed by a straight edge following the prescribed curve. An immediate addi- tion may be made, if necessary, of a thin coat of mortar to give a final surface that is absolutely uniform, without hollows, cavities, or any depressions whatever. ARTICLE n. Paving. When the above-described foundation is sufficiently dry, the contractor must establish upon it a surface of wooden paving blocks conformable to the given samples and laid by the prescribed method. T\\Z paving blocks shall be of first quality Swedish red fir, made by sawing planks perpendicular to their length so as to give a length of o.22m. to 0.23111. (8f inches to 9 inches), a width of o.y6m. to o.ySm. (3 inches to 3-J- inches), and a height of 0.15111. (5-J inches). The blocks must be homogeneous and free from knots for a distance of o.5m (ij inch) from the upper surface. Sound sap-wood only will be accepted, of varieties approved by the Administration. The angles must be sharp and the faces perfectly square. No deficien- cies will be tolerated in this respect nor in the sawed height, which must be precisely o. ism. (5^ inches). The blocks must receive in the contractor's shops a preparation protecting them as much as possible from dampness. The Administration reserves the privilege of exercising in the shops a special surveillance to insure the original quality of the blocks and the proper application of the different preparations required in the process proposed and agreed to by the contrac- tor. These applications must all be made in the shops and never in the yards, where the blocks must arrive ready for use in the work. The blocks must be set on end in regular rows normal to the axis of the road. The joints in adjacent rows must be staggered and blocks of o.nm. (4! inches) may be used to attain this require- ment. The blocks in each row must be set in close contact, but joints of from o.ooSm, to o.oiom. ( T 6 7 inch to - f \ inch) must be left between consecutive rows. At the crossways the rows shall be arranged as directed by the engineer so that no continuous joint shall occur in the direction habitually followed by the carriages. WOOD PAVEMENTS. 97 The surface of the pavement must be perfectly regular, and present the exact longitudinal slope and transverse curvature required. The joints must be dressed with a mortar containing at least one part of Portland cement to three parts of sand. The hold of the blocks before the joints are filled must be assured, either by a wash of some material like coal-tar, filling the bottoms of the joints, or by some other process previously agreed to by the Administration. Whatever system may be adopted, all the joints must be exactly filled and present no cavities. A space of a maximum width of 0.035111. (if inches) will, however, be left along the edges to allow play for the swelling of the wood. After the completion of the pavement the contractor can, if he thinks it expedient, spread, at his own expense, a bed of fine gravel over the surface ; this gravel will be swept off at the expense of the Administration as soon as its engineer deems it requisite for the interest of the traffic, and may be replaced by the contractor at his own expense under the same conditions and as many times as he thinks useful. ARTICLE 12. Time allowed. The work of paving will not be undertaken until after the completion of all sewers and the modifica- tion of the subterranean canals of every nature. The work will be commenced at a date fixed by the engineer, and must be completed within a maximum period of one day for every 450 square meters (4.842 square feet), and fifteen days more for the putting in train of operations i.e., the time necessary for removing a portion of the road from the moment it is occupied for demolition until it is re-opened for traffic. This period is rigidly fixed, and will only be extended in case of continuous freezing weather ; for every addi- tional day consumed in the work 100 francs will be retained from the contract price, unless the contractor can present sufficient excuse. The work shall be simultaneously executed over only about one-half of the width of the roadway in such a manner as to preserve the other half free for traffic. The portions of the read simultaneously withdrawn from traffic shall not exceed 300 m. (9,842 feet) for each station. The number of stations will be fixed by the Administration. At crossings the work must be conducted so as not to interrupt the traffic on the transverse streets, which must not be barricaded except in case of absolute necessity, and with the assent of the Administration. 98 WOOD PAVEMENTS. CHAPTER III. Maintenance and Delivery. ART. 13. The contractor will be charged with the duty of maintaining the wood pavement for eighteen years from the ist of April following the completion of the entire work. This maintenance will consist in preserving the surface and regularity of the profile, and in making all general or partial repairs necessary to keep the road in a perfect state, even if the dilapida- tions are the result of accidental causes, as fires, sinking of the subsoil, etc., excepting only the digging of pits. The maintenance also comprises the removal of the old material, and the tools, plant, etc., used on the new work. ARTICLE 14. The contractor will be required to make general repairs on all portions of the road where there is : i. A reduction of the curve diminishing the original pitch by a least one-quarter. 2. Where the thickness of the paving blocks has been worn away 0.07 m. (2| inches) or more. 3. Depressions or partial defects of the road numerous enough to make it rough, the Administration being judge of the time when it shall be required for this reason. All the requirements of the foregoing Articles, 10, n and 12, are applicable to the work of general repairs. The beton foundation will generally be preserved by simply adding Portland cement beton on top if there is room for it and its removal will not be obligatory except in case of its bad condition. ARTICLE 15. Besides the general repairs the contractor must insure the constant good state of the pavement \y$ partial repairs that may be necessary. He must immediately replace paving blocks that are decayed, crushed, broken or depressed by any cause what- ever, also those which have become impregnated with urine or other offensive liquids, and emit a bad odor. He must repair holes whose depth reaches 0.02 m. (f inch) for a length of i m. (3.28 feet) in any direction. At the junction lines of the wooden pavement with the stone or asphalt pavement the Administration may require the paving blocks to be replaced when they shall have been worn away o.oi m. (^\ inch). In all partial repairs the new pavement must have the same level as the adjacent ; no projections will be tolerated. If any of the defects enumerated in this article are not repaired within three days after notification, a charge of 2 francs per square meter (10.76 square feet) will be deducted from the contract price for each day's delay. ARTICLE 16. Renewals for trenches opened by the Administra- tion, for any cause, must be executed in the same time and under the same restrictions as above, under penalty, if delayed, of 5oc. per square meter per day, unless this amount should be less than 2 francs per trench per day. WOOD PAVEMENTS. 99 Always, except in urgent Cases specified by the engineer, the contractor shall have the privilege of constructing, in not more than fifteen days, at his own expense, the gutters with pebbles or broken stone carefully leveled and rammed. The methods employed must permanently prevent the scatter- ing of rolling stones over the adjacent surfaces. The renewed por- tions will immediately pass into the maintenance of the contractor, who must preserve them according to the conditions of Article 15. No claims will be allowed for repairs required by sinking of the earth. The contractor will only be paid for the area of the trenches measured when filled up. ARTICLE 17. The old material and rubbish from the general repairs must be entirely removed to the work-yards at the expiration of the time allowed for the completion of the work, in default of which the contractor will be subjected to a penalty of 3 francs per day for each deposit not removed. For partial repairs and trenching the removal must be made the same day the work is executed, under the same penalty for delay. Finally, the materials of the wooden pavement, including its foundation, displaced by digging trenches, must be removed the day the trench is opened, or when notified by the engineer if this occurs subsequently. In default of this the contractor is subject to the same penalty, and is entitled to no compensation for loss of materials. ARTICLE 18. The cost (>f sprinkling the streets will be sustained by the city, which will also pay for necessary scouring. ARTICLE 19. At the expiration of eighteen years as defined in Article 13, the roads must be delivered in perfect condition. Three months before the expiration of this time the engineers will make a statement accompanying that of the contractor, who shall furnish at his own expense a certain number of soundings. The road shall not be received unless it satisfies the following requirements : (i.) There must be no holes having a depth of 0.015111. f-inch for i m. (5.28 feet) in any direction. (2.) The transverse curve of the surface must not at any point be reduced so that the pitch is less than four-fifths of its original value. (3.) The thickness of the blocks must at no place be less than o.i 2m. (4! inches). After the engineer's inspection and report the contractor will be allowed three months to place the work in required condition. CHAPTER IV. ART. 20. Payments must be promptly made by the contractor for the wood pavement to the sub-contractors for the IOO WOOD PAVEMENTS. demolition of the old roads and removal of their materials, and if this is not voluntarily done the amounts will be paid from the con- tractor's annuity by the Administration upon the engineer's certifi- cate. The demolition and removal of old roads, the preparation of road bed and establishment of the wood pavement will be remuner- ated only by the fixed annuity, which will also include the interest on, and payment for, the expense of the original outlay and the required maintenance. The total amount of this annuity is fixed in the contract and is subject to no variation during the period of the contract ; it will be paid to the contractor for eighteen years beginning, for each street, on the first of April next after its completion. ARTICLE 21. The contract price fixed for the renewal of the pavement will be paid for the repairs of the trenches, the demolition of the pavement being at the expense of the company opening the trench. The contractor must, if necessary, relay the pavement with entirely new materials, and can make no claim for damages to the work or its maintenance. ARTICLE 22. The Administration reserves the privilege to suppress, at any time, a part or the whole of the wood pavement, and will, in that case, pay the contractor the amount per square meter agreed upon in the relative clause of the contract. ARTICLE 23 relates to the non-fulfillment of the contractor's obligations and the penalties incurred by delays, etc. ARTICLE 24. The annuities will be payable at the first of each quarter, subject to not more than two months' delay. Of each quar- terly payment a sum will be withheld amounting for the first six years to o.io cent., for the second six years to 0.15 cent., and for the last six years to 0.25 cent, per square meter. These amounts cannot be reduced, and will be deposited in the municipal treasury, where they will form a total sum of i2f. per square meter, constituting a guar- antee fund for the maintenance of repairs, etc. ARTICLE 25. The above sum will be repaid, without interest to the contractor at the expiration of the eighteen years, if he delivers up the roads in satisfactory condition ; but in default of this a part or the whole of the amount may be used by the Administration to execute the repairs. ARTICLE 26. If the contractor abandons the work he will forfeit all claim to any annuity and the securities deposited, and will receive no payment for materials furnished. CHAPTER V. Obligations of Contractor. ART. 27. The con- tractor's carts or wheelbarrows will not be permitted on the side- walks, crosswalks or promenades. If a pitchy material is used in WOOD PAVEMENTS. IOI the bottom of the joints between paving blocks, it must be brought, ready for use, from the shops, or prepared in closed furnaces arranged to produce no smoke. ARTICLE 28. The contractor must inclose and properly light his shops, work -yards and store-yards, and provide watchmen when necessary. He must light them only with lamps or closed lanterns. He must, irrespective of police requirements, have at least one lantern for every 10 meters (33 feet) of the length of the work-yards. ARTICLE 29. The contractor will be responsible to the city and to property owners for damages from fires originating in, or propa- gated by, the wood pavements. ARTICLE 30. The contractor will be responsible to the city for the consequences of any thrusts which may result from the expan- sion of the paving blocks, or the action of ice in the open spaces left at the sides of the roadway. Such repairs will be executed by the city, and their cost deducted from the contractor's deposit or the payments due him. ARTICLE 31 requires the surrender of any patent rights. ARTICLE 32. The contractor is required to live in Paris, and must not absent himself without authorization from the Administra- tion and duly providing for all the operations of his work. The contractor or his agent must report at the engineer's office at a fixed daily hour, to receive instructions and report the progress of the work. The engineer will give him a bill of the work to be executed the next day, and of the expenses, for his approval. ARTICLE 33. The contractor must employ none but French workmen. ARTICLE 34. One per cent, will be retained from all payments, for the benefit of the national asylums of Vincennes and Vesinet. Schedule of Prices, Subject to Decrease by the Adjudication. No. i. Annuity, comprising the interest and payments of all cost of changing the existing roads to wood pavements with a beton foun- dation, and the contract maintenance of these roads for 18 years, 4.8of. per square meter (10.8 sq. ft.) No. 2. Annuity to be paid in case of suppression, by the administration, of the wood pavement before the expiration of the 1 8 years, 2.4of. per square meter of surface of pavement suppressed. No. 3. Renewal of wood pavement at trenches, comprising the removal of old material, but not including the demolition, 23f. per square meter. I WOOD PAVEMENTS. SPECIFICATIONS FOR WOOD PAVEMENT ON THE STRAND, LONDON.* There is given below a copy of the form of contract and speci- fications used in 1887, under which wood pavement was laid on the Strand, London. The italics are ours. It will be noticed that the concrete foundation is extra thick where pipes are laid. Arthur Ventris was surveyor to the Strand Vestry in 1887 : Specification of works required to be done in forming and constructing a wood carriage-way pavement upon concrete foundations in . . for the Board of Works for the Strand District under the direction of the surveyor for the time being of the said Board of Works. The works comprise the formation of paved carriage-ways in the fol- lowing sections, viz.: which is in all about yards, as otherwise hereinafter defined, and sub- ject to the conditions specified, and the maintenance of the same in thorough repair for the period hereinafter mentioned. Contractor Responsible. Levels. The contractors to set out and keep correct the works in every particular according to this specification, or by the directions they may receive from time to time, and to be held responsi- ble for the correctness of the work throughout the whole term of this con- tract. The levels referred to in this specification are the finished levels of the surface or distances therefrom, and shall form at the channels a true and even incline towards the gullies or channels of existing streets, showing a sufficient and proper depth of kerb, the surface of the wood paving and of the concrete being formed transversely to a curved surface, having a rise from side to center of not less than i inch in 5 feet, except where otherwise directed by the surveyor. Plant and Material. The contractors to supply every kind of plant, fencing, lights, watching and material that may be necessary to execute the works, including all horses, carts, water carts, and rolling, if required, and to leave the whole at its completion, in a sound and perfect condition, to the satisfaction of the Surveyor to the Board. Interference "with Traffic. The contractors are to give all notices that may be legally or fairly demanded, to the owners or occupiers of the prop- erty, or to the gas and water companies, or to any other person or persons who may be fairly entitled to consideration, and as far as practicable, to study the public as well as private convenience during the progress of the work, and to provide intelligent and responsible foremen to superintend the same, and generally to perform the work with as little interference with the traffic as is compatible with a workmanlike and sound completion of the works. The contractors are not in anyway themselves to interfere with the gas or water mains, without the sanction of the various companies, except the said mains or house services are accidentally injured, in which case the contractor or contractors are to make good such injury at their own expense, to the satisfaction of such company or other party interested. Excavation and Foundation. The roadway from time to time will be handed over to the contractors free from the present granite pitching, and the contractors, except as hereinafter provided, are required to excavate to a *xxi, 5. WOOD PAVEMENTS. 103 depth of fifteen inches from the finished surface of the roadway, and to cart away at once such excavation. To form a Portland cement concrete foun- dation, except where otherwise mentioned, nine inches in thickness, mixed in the proportion of seven parts of ballast, to one of Portland cement, and the ballast to be clean Thames ballast and sharp river sand, free from loam, mixed together to the satisfaction of the surveyor. The surface of the con- crete to be properly floated to a true surface, and formed to the required contour of the street. Should the present foundation, however, during the progress of the work be found sufficiently sound to require under the cir- cumstances a less depth of concrete foundation, the same shall be measured and not disturbed, and shall be considered a substitute for concrete to be put in, and the amount shall be deducted from the tendered price at the rate indicated in this contract ; the decision of the surveyor to be final. Extra Work. Where a trench has been opened by either the water or gas company, or where an extra thickness of concrete shall be required by the surveyor, the same shall, if he so direct, be provided, including excavation, and shall be charged as extra work at per six inches in thick- ness of concrete, and the concrete so put in, shall be one foot three inches in thickness, measured from the underside of the wood pavement. The Paving. The wood blocks 6"X3*X9' are to be of the best Baltic red wood or other equally good timber, prepared in creosote, and shall be placed directly upon the concrete in rows across the street, the joints to be grouted with cement grout or run in with hot bituminous mastic (the kerb joint excepted); the cement grout to be composed of one part of Port- land cement to three parts of sharp river sand free from loam, the whole to be covered with a top dressing of improved ballast. The works are to be executed in the following manner : Section No. i shall be commenced from the end, and the whole of the excavation shall be made and the foundation completed, within days from the day following the closing of the street, and the wood blocks shall be laid complete and the section opened for traffic in six days further, making in all days including Sundays, from the day following the closing of the street. The removal of the granite pitching will be undertaken by the Board or their agents, but nothing shall exempt the parties to this contract from the terms of this clause, except as hereinafter provided. During the excavation and the forming of the foundation, the work shall proceed night and day subject to an increase on the sum tendered per yard of 10 per cent. , but this work shall be required to be done by notice in writing under the hand of the surveyor, and should no such notice be given the work shall proceed with due speed, and the excavation and foundations shall be completed within and the blocks shall be laid and the whole thrown open for the traffic in a further period of six days, mak- ing in all from the day following the closing of the street. Section No. 2 shall be executed in two halves longitudinally or other approved method ; access being given as far as possible to and to and these streets shall not be blocked at one and the same time, neither shall the roadway of be entirely blocked, unless with the written consent of the surveyor. The removal of the granite pitching will be undertaken by the Board or their agents from time to time, but the join- ing of the concrete foundation shall be made in a manner as directed by the surveyor at the expense of the contractors, and the work shall proceed with due speed and be completed within from the date of commence- ment of Section No. i. IO4 WOOD PAVEMENTS. Section 3 comprises the taking up of the wood pavement where directed, and of making up the present concrete to the required levels, and floating to a true and even surface, the surface having previously been picked over and thoroughly cleansed by washing, etc. , the laying of wood blocks as hereinbefore specified run in or grouted, and top dressing thrown on, and open for the traffic in from the date of commencement of this section, and the price to be paid per yard for this work shall be the sum tendered for this section. Extension of Time. That the surveyor, if by reason of the Metropol- itan Board of Works failing to give the necessary permission to close the street, or he sees just cause, shall grant an extension of time by writing under his hand, such extension of time to be either prospective or retro- spective, and to assign such other day or days for completion as may to him seem reasonable, without thereby prejudicing or in any way interfering with the validity of this contract. Inferior Materials, etc. Should any materials be brought upon the works, or should there be any of the workmanship which, in the judgment of the surveyor shall be of an inferior description and improper to be used in the works, the said material shall be removed, and the workmanship amended forthwith, or within such period as the surveyor may direct. In case the contractor shall neglect or refuse to comply with the foregoing conditions, it shall be lawful for the surveyor on behalf of the Board and by their agents, servants and workmen, to remove the material and work- manship so objected to or any part thereof, and to replace the same with such other materials and workmanship as shall be satisfactory to him, and the Board, on the certificate of the surveyor, to deduct the expense thereby incurred or to which the Board may thereby be put or liable, or which may be incident thereto from the amount of any money which may be or may become due, or owing to the contractors, or to recover the same by action at law or otherwise from the contractor, as the Board may deter- mine ; and in case the contractors shall fail to carry on the works with due diligence and as much expedition as the Board or their surveyor shall require, or neglect to provide proper and sufficient materials, or to employ a sufficient number of workmen to execute the works, the Board or their officers shall have full power, without vitiating this contract, and they are hereby authorized to take the works wholly or in part out of the hands of the contractor, and to engage or employ any other person or workmen, and procure all requisite materials and implements for the due execution and completion of the said works ; and the costs and charges incurred by them in so doing shall be ascertained by the surveyor, and paid for or allowed to the Board by the contractors, and it shall be competent to the Board to deduct the amount of such costs and charges out of any moneys due or to become due from them to the contractors under this or any other contract. Fines. That time shall especially be considered as the essence of this contract on the part of the contractors : and in case the contractors shall fail in the due performance of the works to be executed under this contract by and at the times herein mentioned or referred to, or other day or days to which the period of completion may have been extended, they shall be liable to forfeit to the Board the sum of ^50 for each and every day which may elapse between the appointed and actual time of completion hereinbefore mentioned, or the Board may deduct the same from any moneys in their hands WOOD PAVEMENTS. 105 due or to become due to the contractors, and such payments or deductions shall not in any degree release the contractors from further obligations and forfeitures in respect to the fulfilment of the entire contract. Tenders. The contractors shall state in their tender the price per yard for wood paving laid on concrete, including excavation, in every respect according to this specification. Where, however, the surveyor may deem it necessary to order the contractors to execute extra work in connection with these works hereinbefore described, such extra work shall be paid for by the Board at prices to be fixed by the surveyor, and to be accepted by the contractors. Maintenance. The contractors shall keep and maintain the works in sound condition to the satisfaction of the surveyor, for two years next after the completion of this contract, free of cost to the Board, and shall, if required so to do in writing under the seal of the Board, keep and main- tain the aforesaid works in whole or in part in sound condition to the satis- faction of the surveyor for a term of years (to be stated in the tender) for the tendered sum per square yard per annum, first payable on completion of the third year from the date of completion of the works. Payments. The contractors shall be paid one-third part of the con- tract on completion of one-half of the works, and one further third upon completion of the works, and one further third six months after such com- pletion, but only upon the certificate of the surveyor of the satisfactory completion or condition of the said works according to the specification. SANITARY ASPECTS OF WOOD PAVEMENTS.* This is a report of a Board appointed to inquire into the alleged deleterious effects of wood paving upon the public health. The subject of pavements of different kinds in relation to cleanliness, freedom from noise, and surety of foot-hold is first discussed and the conclusions of the Board summed up in the table on page 106. From this comparative statement it appears that no one pavement has; all the qualities which are necessary to make a perfect pavement. Mono- lithic asphalt comes nearest to the model. It is the only material which can be kept perfectly clean, and it costs less for cleansing than any other. In point of hardness, smoothness, and noiselessness it is unmatched. But it is adapted only to low grades grades so low that it is practically useless in this city except for sidewalks, and this failure depends upon the qualities of smoothness and hardness which, important as they are in other respects, render the foot-hold comparatively insecure. In a similar way each other kind of material may be criticised. Some objections, varying in character with the kind of road, appear in all ; and these are only in part overcome by varying the material with the kind of country over which the road is taken, and with the kind of traffic for which it will be chiefly used. What- ever material is chosen from among those which, up to this date, are available, the pavement made with it must be a compromise. There is, at present, no pavement which can be called "best;" only some kinds are less objectionable than others. legislative Assembly, New South Wales, Wood-Pavement Board Re- port, Sydney, 1884. xi, 331. io6 WOOD PAVEMENTS. The Board examined some specimens of wood pavement as laid in the city of Sydney, taking up blocks at different points. In all cases the concrete bed underneath was moist ; in three cases a large amount of slimy mud was found, giving off an ammonical odor. In all these the joints and blocks appeared to be uninjured. The blocks were chemically examined to determine whether they had absorbed organic matter, with the result that some were found impregnated with filth to the very centre, while others were comparatively free from it. A MODEL ROAD- PAVEMENT. GRANITE BLOCKS. SHEET ASPHALT. WOOD BLOCKS. MACADAM. Should be imper- vious. 'oints pervious, equal to one- third of surface and retentive. Impervious. Absorbent and retentive. Pervious. Should afford good foot-hold. Fairly good. Good. Variable. Good. Should be hard. Too hard, injur- ing horses' feet and vehicles. Hard and elastic Not sufficiently hard. Soft. Should offer little resistance to trac- tion. Considerable. Little. Variable with age, etc. Medium. Should be noise- less. The most noisy The least noise. Less than granite more than asphalt. Less than gran- ite; more than asphalt. Should be cheap. ? ? ? ? Should yield no detritus. Less than ma- cadam; more than wood or asphalt. Yields less detritus. Least, except as asphalt. Yields most detritus. The surface should be easily cleansed. Less easily than asphalt. Most easily cleaned. Not easily cleaned Not easily cleaned. Should suit all traffic. Practically suits all. Suits all traffic Does not suit very heavy traffic. Not heavy, traffic. Should be adapted to every grade. Not to very steep grades. Grades must not be more than 1-50. Not to very steep grades. All grades. The Board comes to the conclusion that wood is a material which cannot be safely used for paving unless it can be rendered absolutely impermeable to moisture, and so laid that while the entrance of water between the blocks is rendered impossible the separation of the fibres at the surface by the concussion of traffic is also effectually prevented. These conditions have nowhere, to the knowledge of your Board, been fulfilled. So far as the careful researches of your Board go the porous, absorbent, and destructible nature of wood must, in its opinion, be declared to be WOOD PAVEMENTS. 107 irremediable by any process at present known ; nor were any such process discovered, would it be effectual unless it were supplemented by another, which should prevent fraying of the fibre. Still less can the defects of wood be considered to be of less consequence than the defects of other kinds of material. In this city it may, perhaps, be considered that an amount of wood has not yet been laid sufficient to affect the public health, whatever its condition within reasonable limits may be ; and upon this ground your Board doe s not recommend that the present paving should be removed, but that the Board of Health should be empowered to examine it, and to report upon it, from time to time, with a view of ascertaining its behavior under longer exposure to weather and traffic than it has yet had, and that it should be no longer watered, but cleansed by sweeping at least twice a day ( the sweep- ing to be done at right angles to the direction of the street or parallel to the courses, so that the latter may be cleared out by the broom) in order that destructive dampness and penetration of dissolved organic matter may be reduced as much as possible. But the presumption is upon the evidence here adduced, that in this climate the results alluded to would ensue if the extent of surface were sufficiently enlarged or fouling and decay sufficiently extensive. Your Board, therefore, recommends that the paving of the streets of this city with wood should be discontinued, and desires to add that this recommendation is intended to apply not to the particular mode of construction here adopted alone, but to the material itself, and to every known method of construction. The appendix to the report contains some interesting data with regard to wood pavements, and the volume is one which municipal engineers will find interesting and valuable as a book of reference. NECESSITY OF MAINTAINING A WOOD PAVEMENT.* In the summer of 1883 a wood-block pavement was laid on Fifth Avenue, between Thirty-second and Thirty-third Streets. A good concrete foundation was carefully laid to the proper grade and transverse profiles ; on this blocks of pine which had been dipped in dead oil not thoroughly creosoted were laid in rows about one-eighth of an inch apart. Enough bitumen was pou r ed into the interstices to hold the blocks in place, possibly a quarter of an inch in depth; the interstices were then filled with a Portland cement concrete, the whole covered with a top dressing of hard, clean gravel about the size of peas, and when the concrete had had time to set traffic was turned on to the pavement. This pavement has stood since then, it is believed, without any other attention or repairs than sweeping. It has not even received a coating of gravel, which in European practice it would have received, on the theory that the gravel crushing in between the end fibres of the wood prevents wear to some extent. * Ed. xviii, 49. IO8 WOOD PAVEMENTS. All this time it has been almost entirely free from noise. It has been cleaner than any stone pavement in the city, and has been the pleasantest and safest piece of pavement in the city to drive over. Now through inefficient creosoting or inherent weakness in some of the blocks they have commenced to fail, and between one and two per cent, of the pavement requires renewal. The practice in New York has been, with all wood pavements, in such a case to sit complacently and see the depression from a defective block, originally four inches by six, extend over a constantly increasing area, and these areas increase in number until the pavement was irretrievably ruined, when the wood pavements were condemned and the locality took to itself a stone pavement many times noisier and dirtier than before. It is to be hoped that with the able engineer at the head of our Department of Public Works the old record will not be repeated, but that advantage will be taken of the small traffic on the avenue for the next two months to shut off half of the roadway at a time and replace all defective blocks, allowing the concrete full time to set; and we hope it is not too much to urge that more attention be given to that piece of pavement than it has received in. the past. WOOD PAVEMENTS IN LONDON AND NEW YORK.* Construction and Maintenance. The London Financial Times states that in 1883 the Strand was paved with wood, from Charing Cross to the Strand Post-Office, by the Vestry authorities, and from the Post-Office eastward to St. Mary's Church the work was done at the same time by the Improved Wood Paving Company. " As every Londoner knows, to his cost, the Strand was ' up ' about a month ago, while the paving put down by the Vestry in 1883 was renewed. That laid down by the Improved Wood Paving Company is still good, and has not had to be touched during the six years of pre- cisely the same wear and tear which has torn the other half of the Strand into holes and splinters." A part of the Strand, though it is not now possible to say with certainty which part, required renewal last spring, as the blocks were worn in places to a thickness of less than three inches. The point which is of interest to Americans, and to New York- ers in particular, is that two different samples of wood pavement lasted six years in the Strand, which has fully three times the traffic of Fifth Avenue, while on that avenue a wood pavement was not made to last five years before a barbarous return to stone was made. The difference in the wearing of wood pavements in the two cities lies entirely in the fact that in London a pavement of any kind * Ed. xx, 329. WOOD PAVEMENTS. lOp is maintained. But the City of New York, for the past twenty years, has not been able to get authorities who understood the necessity of maintenance. The pavements have been patched, and they have been renewed, but not maintained. The Engineering and Building Record from time to time called attention to the necessity of re- placing the few blocks in the wood pavement formerly on Fifth Avenue which had proved defective, but we think nothing was done until the places started by single defective blocks were so far extended that the pavement was condemned and replaced by stone blocks. Profits in Paving. Moreover, the companies that have put down and maintained for the maintaining part of the contract is gener- ally well enforced London pavements for the local authorities seem to have themselves been very prosperous. The Financial Times says that the Improved Wood Paving Company paid 5 per cent, for four years ending with 1882, 8 per cent, in 1883, and has paid 10 per cent, since. The Val de Travers Asphaltic Company pays not less than per cent., and the Compagnie Generate des Asphaltes de France, both doing business in London, yields a steady return to its shareholders of i on each 6 share ! The Limmer Company, also laying asphalt, met with heavy losses at the start in consequence of poor material, but is now paying satisfactory dividends. The necessity for having responsible, and therefore prosperous, com- panies to deal with is obvious, and the statements of the London contemporary certainly make a strong argument in favor of paving contracts with the maintenance feature, from all points of view. RAWLINSON ON WOOD PAVEMENTS.* Mr. Robert Rawlinson, writing to The Builder, on wooden pavements, which are now being laid extensively in London, says : The character of wooden pavements may be known by the occupants of carriages in driving over them. Where the blocks are laid upon sand and boards, the vibrating and drumming effects are most distressing. When laid with open joints the surface becomes rapidly worn and uneven ; and when laid upon an imperfectly-formed or weak foundation, the surface also becomes uneven, alternately hills and holes, retaining dirt and wet, and so tending more and more to the destruction of material and the road. Blocks of wood, unexceptional in character, form, and dimensions of mate- rial, laid hard on an exceptionally good cement concrete foundation, close jointed, but without the felt bedding and jointing have a disagreeably jarring effect, though in a less degree than the examples previously described. Some of the wood-paving companies must have been very stupid, and also very difficult to teach, or they would have learnt by their failures, sooner than they appear to have done, and we should not then have seen *vi, 67. 110 WOOD PAVEMENTS. most important main thoroughfares blocked for weeks at a time by the pulling up of the entire wood construction to begin again as from the beginning, and this process more than once over. ********* Cement foundations for wood-block paving ought to have ten or twelve days to "set," but in London this time can seldom, if ever, be given, and this may, in some cases, account for partial failures. Wooden pavements, in themselves, make no mud, but this is carried on from adjoin- ing dirty macadam and "set" paving. When, therefore, wooden pave- ments are muddy, it shows neglect in street-scavenging. PAVEMENTS OF COMPRESSED WOOD.* The increased favor with which wood-pavements have of late come to be regarded in European cities, has led to the devising of numerous processes that have for their object the preparation of wood for use in pavements. In a process of this kind, on the one hand, of course, strength and durability of the product must be aimed at ; on the other, it is necessary that the working expenses be as low as possible. In this connection we note an article in the Semaine des Con- structeurs on the process of Cyprien Mallet, which is said to fulfill these requirements. The salts of the metals and various other substances having the property of preserving wood from decay, Mallet injects, hot, into the core of the pine-trees, an antiseptic fluid, and then compresses the logs about i-io their volume. The antiseptic liquid is composed of : copper sulphate, 6 kilos ; juice sulphate, 6 kilos ; sodium chloride, 3 kilos, which are dissolved by boiling in 35 litres of water containing no lime salts. Without interrupting the boiling, there is added then : resin oil, 40 kilos ; heavy oil, 40 kilos ; suet, 10 kilos. This solution is concentrated to a certain degree over a moderate fire. Ten litres of this liquid mixed with 90 litres of boiling water is the fluid used. The wood charged with this preparation becomes very hard, yet it retains sufficient elasticity ; it is not affected by the weather. In Paris the cost of a pavement of this kind comes to about four dollars per square meter. CEDAR BLOCKS VERSUS ASPHALT FOR STREET-PAVEMENTS.f CEDAR RAPIDS, IOWA, March 16, 1887. SIR: Do you think cedar blocks for street pavements as healthful as asphalt or other non-absorbent material ? For like reasons, are the blocks when placed on boards and not treated with creosote as good as when treated and put on concrete ? Respectfully yours, JOSSELYN & TAYLOR. *ix, 503. fxv, 431. WOOD PAVEMENTS. Ill [Answering the questions of our correspondents in order, we would say: First That on general principles, that pavement from which water passes away with the least percolation to the soil below and which can be most thoroughly and easily cleansed is the most conducive to health. Second No pavement placed on boards or directly on the earth is as durable as when placed on concrete ; this is the universal verdict of all municipal engineers who have had opportunity to observe the matter, and the latest practice in France and England, where wood has been used, is to make a carefully formed and substantial concrete foundation for the blocks. Third Creosoting undoubtedly adds to the life of the blocks, by mak- ing them wear out rather than decay irregularly. This question is compli- cated by the secondary ones of amount of traffic, kind of timber, care in selection, proper seasoning, etc. Abroad a most rigid inspection is made, the blocks are thoroughly seasoned and thoroughly creosoted. Fourth The selection of a pavement should be guided among other things by the question of amount of traffic. On some streets in our cities nothing will stand the wear but the best granite blocks. Original cost oftentimes becomes also the deciding motive. We think it can scarcely be questioned that asphalt is superior to wooden blocks, provided other con- siderations do not essentially alter the conditions.] CEDAR BLOCK PAVEMENT IN ST. PAUL.* A recent number of the Pioneer Press, of St. Paul, Minn., contains the following. Durability. The cedar blocks taken up on East Seventh Street dur- ing the construction of the cable conduit show an average wear of less than a inches. This is very noticeably light, because that pavement was the first cedar block pavement put down in St. Paul. This was in 1882, seven years ago. The pavement is good for ten years of service yet, with occasional repairs, and that is a first-class record on a street where a heavy traffic is carried on. The blocks are in a perfect state of preservation. The planks beneath them are i-inch planks, but show some effects of seven years' pound- ing. Two-inch planks are used now. In regard to the above item L. W. Rundlett, City Engineer of St. Paul, says : The statement of the Pioneer Press is not strictly correct ; the pav- ing was laid in 1882 and was among the first cedar block pavements put down in the city. The roadway is 40 feet wide, with street car tracks occu- pying a width of about 15 feet in the centre. It is a retail street and one of the principal thoroughfares of the city, although not subject to as heavy traffic as some other streets. On account of the street car tracks being in the centre the line of travel was thrown to a considerable extent on each side of these tracks, which made the wear somewhat unequal ; the wear of the blocks, more particularly in the line of travel, being from 2 to 2^ inches; the blocks originally being 6 inches in depth. The blocks themselves show very little decay, some of the foundation boards, which were only an inch * xx, 86. 112 WOOD PAVEMENTS. thick (our present construction is 2-inch plank) were somewhat decayed, and in repairs probably 25 per cent, were renewed. The Water Board have put down a larger main on the street this year ; the gas company have put down a new gas main, and the cable line has been substituted for the horse line ; a subway for putting wires underground is also in process of construction. This work, with the necessary changes in the house connections, has caused the street to be pretty well torn to pieces ; we have, however, used considerable care in replacing the blocks, and I think it will probably be about three years before the street will require to be repaved. WOOD PAVEMENT IN DULUTH. * f Cedar blocks were used for paving and were laid upon a per- manent concrete foundation, so that when the traffic on the street became heavier, stone blocks could be substituted in place of the cedar without relaying the foundation. The method of 'laying the pavement was as follows: After the street was brought to the required sub-grade it was repeatedly rolled with the steam road-roller. A granite curb was then laid on either side, under which was a tile drain, to prevent water getting under the concrete. The concrete of the foundation was then laid six inches deep over the entire roadway, and was composed of five parts natural cement, twelve parts coarse sand and twenty-four parts broken stone, well mixed together and quickly laid in place. The surface of the concrete was then made smooth by a thin layer of mortar, consisting of one part cement and two parts sand, brought to the right form by means of templates. This was allowed to harden for about five days, when, outside the street car tracks, round cedar blocks were laid directly on the concrete and covered with tar and gravel in the usual manner. The street car company paved the space between the rails of their track with granite blocks set in sand. Where the grade is 10 feet in 100, cedar block pavement would have been too slippery in wet or frosty weather, so rectangular pine blocks four inches wide were laid on end in parallel rows, three- quarters of an inch apart, on a 2-inch plank foundation, the space between being filled with gravel and tar. A twenty-ton Aveling & Porter steam road-roller was purchased in 1887. During the first months it was constantly in mud holes, owing to the fact that there were but few street foundations in the city strong enough to hold it up. All contractors were required to use it, however, and the result has been far more faithful work on * Second Annual Report of the Board of Public Works of Duluth, Minn., for the year ending February 28, 1889. William B. Fuller, City Engineer. t*x, 53- WOOD PAVEMENTS. 11$ their part than could have been secured in any other manner. In the preparation of street foundations and for rolling macadam paving this roller has been invaluable. CEDAR-BLOCK PAVEMENT AT LEAVENWORTH, KANSAS.* Noticing in an exchange a discussion regarding proposed new pavements for Leavenworth, the statement that a cedar -block pave- merit on a certain street had proved a failure, we wrote to City Engineer George T. Nelles, asking for facts and details as to the manner in which the pavement was laid. The following is from his reply : The pavements in question were put down on two of our principal business streets and on one resident street, and consisted of y-inch sound white-cedar blocks 4 to 8 inches in diameter laid on a 6-inch concrete foundation. The work was all done in accordance with the specifications in general use for this class of work. The work was done during the summer and fall of 1887, so that the reliable test of use cannot be brought into play. So far as I am able to judge, from my knowledge of the manner in which the work was done, and from present indications, the work will prove as permanent and lasting as any pavement of this class. The cedar blocks were of unexceptionally good quality, live and sound, and free from the usual imperfections of this class of material. The assertion made in the clipping herewith to the contrary is absolutely without foundation. Owing to the inferior quality of the sand and broken stone available here for carrying on works of any magnitude, the concrete foundation may not be up to the standard. Still, I confidently believe it is ample for the purpose, and that it will outwear a great many sets of cedar blocks. I have recently had occasion to examine some of the concrete laid during freezing weather last fall, and found that, although not perfectly set, it has not been in the least disturbed by the frost or the traffic over it. I have not arrived at the true inwardness of the attack on cedar pavements, but think that the idea that the pavements laid last year are failures arose from the fact that several very ugly settlements have taken place where the pavement was laid over heavy fills, which, until repaired, greatly injures the appearance of the work ; and from the fact that the blocks raise along the street-car line, which was put down without cross- ties by laying the stringers directly on the concrete, and being dependent entirely on the blocks to hold it down, and, in consequence, has raised the blocks in places. There is nothing, so far as I can see, connected with this work that can be cited as an experience with cedar block pavements. COST AND DURABILITY.f A Report on Pavements, made to the Common Ccuncil of Topeka, Kan., says : Wood pavements of the old varieties are con- ceded to have proved failures. The white cedar blocks (more prop- erly cypress) sawed from small trees are being laid in Chicago, Kansas City, Omaha, upon concrete foundations and also on boards. *xvii, 323- t*v, 375- 114 WOOD PAVEMENTS. The life of the latter they consider to be about three years. That on concrete would cost in Topeka about the same as granite block, or sheet asphalt, and if the cypress blocks were creosoted, as are the pine blocks now used in England and France, the cost would be still greater. PLANING DOWN A WOOD PAVEMENT.* Some recent experiments in Manchester, dealing with the ques- tion of repairing roadways laid with wood blocks, are of consider- able interest to vestries and public boards. Hitherto, owing to the unequal wear of the blocks in any one roadj resulting from the varying density of the wood, it has frequently been necessary to pull up and relay a road with new blocks, discarding all the old ones, of which, possibly, a great number may have had good " life " in them still. To obviate this necessity Mr. A. C. Bicknell, of the Sandycroft Foundry Company, Chester, has invented a machine of traction-engine type, self-propelling, having in front a revolving table fitted with cutters. A section of a road was laid with old blocks, which had been discarded as unfit for further service. The method of laying was the usual one, in cement and sand, and being composed of old blocks pitted with sand and gravel the experimental road presented the normal features of an old road requiring repair. When several days had elapsed, to allow the cement to set, the machine was brought to work, the cutting-head being gauged to cut one-half inch below the surface of the lowest face of the roadway. In the course of the work it was necessary to take off three inches from some of the blocks, and the result throughout was satisfactory. The system of planing down a roadway is certainly novel. *xiv, 224. CHAPTER III. ASPHALT PAVEMENTS. THE NATURE AND USES OF ASPHALT.* ASPHALT is a variety of bitumen, found in a native condition and not manufactured, and in a solid form is commercially known as glance pitch. Glance pitch is found in limited quantities in various parts of the Rocky Mountains and in Texas. It is very pure and is used to make a high grade of varnish, but its brittleness makes it useless for paving or roofing compounds. Occurrence. The asphalt of Trinidad is found in a so-called "lake "about 130 feet above the sea-level, on the island of that name. The "lake "is a level tract, about 114 acres in area, of brownish material of an earthy appearance. It is sufficiently hard to bear the weight of carts and animals, and yet its consistency is such that excavations fifteen feet in depth are filled up by the flow of adjacent material in a few months. It is estimated that the amount of asphalt in the lake is upwards of six million tons. On partial analysis it yields approximately 40 per cent, of pure bitumen, 40 per cent, of earthy and vegetable matter, and 20 per cent, of water. The material is heated in large tanks at a temperature of about 300 Fahr., to drive off the water and let the larger portions of the earthy matter settle and the vegetable matter to be skimmed off the surface. This refined asphalt contains about 60 per cent, of pure bitumen and 40 per cent, of finely divided earthy matter invisible to the eye. This material is too brittle for commercial use, and it is therefore mixed with a heavy, dark oil, known as the residuum of petroleum, in the proportion of six parts of asphalt to one of residuum. This is the material so largely used in paving and roofing compositions. On the coast of California, near Santa Barbara, and also in certain portions of Colorado, Utah and New Mexico, are found large beds of sandstone containing from 15 per cent, to 20 per cent, of bitumen. Recently this material has been used for paving in cities on the Pacific coast, but it has not yet been in use long enough to prove its desirability. * A paper read by Captain F. V. Greene, Vice-President of the Barber Asphalt Paving Company, before the Society of Arts at the Massachusetts Institute of Technology, and published in the Boston Transcript. xix, 258. Il6 ASPHALT PAVEMENTS. In the valley of the Rhone in France and Switzerland, in Sicily, in parts of Italy, in Spain, and in Hanover, there are very large beds of a fine amorphous limestone naturally impregnated with bitumen, and it is from these mines that the asphalt pavements of various cities in Europe have been obtained. Those most suitable for paving contain about 10 per cent, of bitumen and 90 per cent, of fine limestone. Uses. The uses of asphalt may be divided into five classes viz.: ist, as a varnish for paint; 2d, as an insulating material ; 3d, as a water-proofing material ; 4th, as a cement in ordinary construc- tion ; 5th, as a cement in roofing and paving compounds. In its natural state it is too brittle for any of these purposes. For varnish it is mixed with oil of turpentine, linseed oil and shellac. Such varnishes are used on leather, producing the so-called patent leather, and on iron, the black japan varnish being well known. For insulating compounds the exact mixture is not divulged. For water-proofing arches and similar construction it is sometimes used in the form of a layer of mastic, made from bituminous lime- stone spread over the arch, and sometimes as a cement between the joints of the bricks, the bricks being heated and dipped in hot asphalt, and the joints poured with similar material after the bricks are laid. As a roofing material^ asphalt is used in the form of asphalt cement, very similar to paving cement. The roof is covered with one or more layers of felt ; on this a layer of the cement is poured, and before it has cooled fine gravel or pebbles are spread over it. Asphalt Parements. The amount of asphalts used for paving is about 95 per cent, of the total consumption. I shall endeavor to show that the asphalt pavement is the latest and, all things considered, the most satisfactory solution of the paving problem yet devised. It is not as durable as cast-steel, nor as noiseless as velvet, nor does it afford as firm a foot-hold as the loose earth of a race-track. But it is much smoother and less noisy than stone, much more durable than wood or macadam, is water-proof, contains no decaying vegetable matter, can be kept perfectly clean at comparatively small expense, is less slippery under ordinary conditions (as shown by careful observations in Europe and America) than either wood or stone, and it enables larger loads to be drawn by the same force and with less wear on vehicles than any other form of pavement ever used. It has thus many advantages and fewer defects than other pavements in common use. The speaker next gave a brief history of pavements in general, so as to trace the origin and development of asphalt pavements. ASPHALT PAVEMENTS. 117 Macadam. He said that no improvement has ever been devised upon MacAdam's system as a road covering outside of cities. It has also been widely introduced within cities ; London has about 600 miles and Paris 100 miles of it to-day. In America it has always been popular in New England cities three-fourths of the streets of Boston are paved with it but it has not found favor in other cities except on streets reserved for pleasure driving only. Its advantages are a firm foot-hold for horses, and a reasonably smooth surface. Its defects are heavy resistance to traffic, great cost of maintenance, and the impossibility of keeping it clean. When sprinkled it is always muddy, and when dry it is invariably dusty These defects are inherent and cannot be remedied. The Paris Budget shows that it costs over $900,000 per annum in that city for the single item of repairs to macadam pavements. This is equivalent to 45 cents per yard per year. It is estimated that the annual cost of repairing the macadam pavements of Beacon Street, Boston, is 50 cents per yard. Stone Pavements. Stone pavements were next taken up, and figures presented showing that the cost of repairs was from five to twelve cents per yard per year, while the annual cost for laying and maintaining the best quality of granite-block pavements on concrete foundations is twenty-six cents per yard. Wood Pavements. Wooden pavements were shown to cost annually for laying and maintaining about sixty-one cents per yard, but it is now claimed by its advocates in London to be forty-two cents per yard under moderately heavy traffic, or about two-thirds the cost of macadam under the same conditions. Captain Greene gave the experience of Washington as a warning against its use. Upwards of $4,000,000, derived from a loan not yet paid off, were expended in that city under the Shepherd government of 1871-74 in laying fifty miles of wood pavements. They proved a complete failure in a few years, and have all- been since replaced with asphalt at a little more than half the original cost of the wood. Rock Asphalt Pavement. Bituminous limestone or rock asphalt began to be used for paving in Paris in 1854, in London in 1869, and in Berlin about 1880; and its use has been continued with success. The total area of this pavement in use now in Europe is about 1,500,000 square yards, covering a length of about ninety miles of roadway. A uniform system has been used in laying in all the cities. A solid bed of concrete is used to give a foundation. On this the asphalt surface is laid about 2 \ inches thick. The preparation of this surface requires great care and skill. The asphalt rock, as it is quarried from the mines, is crushed in a rock breaker to a size of Il8 ASPHALT PAVEMENTS. about three inches. These are then passed through toothed rollers and again through smooth rollers until the rock is reduced to pow- der. This is then heated in revolving cylinders to a temperature of about 280 Fahr., and the heated powder is carried in carts to the street where it is to be used. There it is spread on the concrete and raked with hot iron rakes until it forms a uniform layer of loose powder, about twice its ultimate thickness. This is then quickly compressed by pounding with hot iron rammers, after which a small amount of hydraulic cement is swept over the surface and the pounding is continued until the pavement will no longer yield under the rammer. It is left until the next morning to cool, when the street is opened to traffic. Cost and Maintenance. In London the first cost has been about $3-75 P er yard, and the maintenance eighteen cents a yard per year, the street to be delivered at the end of seventeen years as good as new. Including first cost, the total expense is forty cents per yard per year. Tar Pavement. The success of rock asphalt pavement in Europe gave rise to a demand for such pavements in America, but the expense of transportation of the rock from France was so great that inventors sought to find a substitute. They first tried the tar produced in large quantities at the gas works, which they erroneously supposed to possess the same qualities as the natural bitumen in the asphalt rock. This was combined with sand, limestone, sulphur, sawdust, etc. The material did not look unlike the real asphalt, and a craze for such pavement started in Washington in 1871 and spread all over the country. The majority of these efforts were complete and costly failures, and as they all claimed to be asphalt, the result was to create a prejudice against all pavements of that character, which it required years of careful experiment and proof to overcome. The defect of them all lay in the tar, which contained volatile matters which evap- orated under the influence of the sun, and left the pavement a mass of dry black powder. Trinidad Asphalt Pavement. A Belgian chemist conceived the idea of using the asphalt of Trinidad as the cementing material, knowing that it had been exposed for centuries to a tropical sun, and that the sun's rays could have no further effect on it. With this he combined clean sharp sand and a small amount of powdered limestone. The sand in it afforded a firmer foot-hold for horses. It was used on a part of Pennsylvania Avenue, in Washington, in 1876, the asphalt-rock pavement of Paris was used on the other part, and they have been in constant use ever since. The French pave- ment proved more slippery and more costly than the Trinidad, and ASPHALT PAVEMENTS. Iig no more of it was laid ; but the Trinidad asphalt gave entire satis- faction, and has been constantly laid with succeeding years, until now its area in Washington alone is but little short of one million yards. After seven years' successful use in Washington, other cities began to use it, Buffalo being the first, and it now rivals Washing- ton in extent of its use. It is now used in thirty-four cities, the total area being about four million yards. These pavements are laid on a solid foundation of concrete six inches in thickness. The asphalt surface is 2^ inches thick, laid in a similar manner to those in Paris. But the asphalt is prepared quite differently. The refined asphalt is mixed with the residuum of petroleum to make the cement. This is heated at 300 Fahr., and the sand is also heated to the same degree ; these are mixed in a large box in which agitators are constantly revolving, and there a complete mechanical mixture is formed. The hot powder is then taken to the street, spread the proper thickness, and immediately compressed by large steam rollers, weighing from five to ten tons. The cost of maintenance for the Washington asphalt pavements is about two cents per yard per year. On many of them, now ten years old, no repairs of any kind have been made, and they are still in perfect order. These streets are subject to very light traffic, and are kept clean. In other cities where the pavements are not kept clean, and the traffic is heavier in some cases the most destructive traffic in American cities the expense is much larger. But under ordinary conditions the cost of maintenance does not exceed ten cents per yard for a long term of years. Including first cost, the total expense of maintenance for seventeen years would be about thirty cents per yard per year. From this it appears that asphalt is a little more expensive than stone, but it is the cheapest of the smooth pavements. Asphalt Block Pavement. Asphalt blocks have been tried, but they are deficient in durability under heavy traffic, but they have been very satisfactory on residence streets of light traffic. These can be laid as ordinary paving stones, thus doing away with an expensive plant in every city. Traction and Cleanliness. On asphalt pavements the same force will draw a load three times as heavy as on the ordinary stone pave- ment. The former can be kept perfectly clean at small expense ; the latter has one-fifth of its service composed of joints filled with stable filth, which cannot be removed in cleaning. If some one gives voice to the current belief that horses are con- stantly falling on the asphalt, I will show him the result of careful observations in ten different cities on 736,000 horses, of which 84 fell on stone pavements, and only 71 on asphalt. The proprietors 120 ASPHALT PAVEMENTS. of the livery stables of Washington and Buffalo say that they inva- riably use the asphalt in preference to the stone pavement, and that there is far less injury to horses, as well as to their vehicles, on the asphalt. ASPHALT PAVEMENTS IN THE UNITED STATES.* At a recent meeting of the Board of Improvements of Cleveland, O., City Engineer Walter P. Rice made the following report of his investigations of asphalt pavements : Material. The best material for pavement purposes seems to be the Trinidad asphalt, which is controlled by the following companies : Barber Asphalt Paving Company, Warren-Scharf Asphalt Paving Company, and National Vulcanite Company. The latter company is able to command asphalt only for laying pavement other than the Barber, while the two former lay pavement under the same specifications, but in separate terri- tory. There can therefore be no competition and but one bid can be received under the same specification, and to all practical intents cities or individuals using the street pavements are subject to such dictation as may be imposed as to cost of all repairs and resurfacing. Washington and Buffalo Pavements. I examined over twenty streets in Washington, D. C., paved with asphalt, vulcanite, and coal-tar distillate. The age of these pavements ranges from five to fourteen years. In general they are in good condition, show frequent repairs, and are subject to light traffic. Pennsylvania Avenue and K Street are typical respectively of heavy and light travel. Pennsylvania Avenue, the pave- ment of which is part Trinidad and part Neufchatel rock asphalt, is about 105 feet between curb lines, age 12 years, never resurfaced, about 10 per cent, of wearing surface gone, largely patched in places, lack of uniformity, some ruts. In K Street the pavement is vulcanite, 50 feet between curb lines, age 14 years, never resurfaced or patched, condition almost perfect. K Street is used as a standard of comparison in all vulcanite specifications. The Buffalo pavements, with a few exceptions, are not yet of a suffi- cient age to justify the formation of any opinion except in case of early failure, as on Broadway, paved three years ago, resurfaced once and giving out again in places. Franklin Avenue, paved with asphalt nine years ago, is the oldest exception and without repairs, is in excellent condition. Cottage and Bryant Streets, paved eight years ago, are in good condition. Formula for Asphalt and Vulcanite Pavements. The reduced formula for asphalt is : Asphalt, 13.16 to 15.78 ; heavy petroleum oil, 1.84 to 2.21 ; fine sand, 70.00 to 65.00 ; pulverized carbonate lime, 15.00 to 17.00. There is little or no bond between the base and wearing surface. The reduced formula for vulcanite is: Asphalt, 4.4 percent.; coal-tar distillate, 13.4 per cent ; clean sand, 53.6 per cent.; pulverized stone, 26.8 per cent.; hydraulic cement, 1.2 per cent.; flour sulphur, .14 percent.; air- slacked lime, .28 per cent. The main differences are the percentages of asphalt and the value of coal-tar distillate versus petroleum. The vulcanite is the cheaper as regards first cost, although costing slightly more for maintenance. *xvii, 361. ASPHALT PAVEMENTS. 121 Defects of Asphalt and Vulcanite Pavements. Asphalt pavements are liable to the following defects : First, the formation of " wave sur- face," especially on grades (probably due to lack of cohesion between the wearing surface and base). Second, the formation of transverse cracks, more apt to occur in wide roads and intersections ai?d undoubtedly due to contraction and expansion, caused by variations of temperature. Third, a rot or disintegration takes place in the gutters and necessitates the use of stone or a coating of coal-tar ; this does not seem to be the case with vul- canite. Vulcanite or coal-tar distillate pavements : First, are affected at a lower temperature than asphalt, and sometimes present evidence of a flow of material toward the gutters during warm weather often rising nearly to the top of the curb and necessitating a cutting away of the material. This is not observable in the asphalt. Second, vulcanite is not so liable to trans- verse cracks (the forerunners of repairs), or to wave surfaces as the asphalt, on account of greater longitudinal strength due to a closer union of base and wearing surface. On the other hand, in making repairs the wearing surface of asphalt can be easily removed and renewed, while in the vulcanite no such separation can be made and in resurfacing it is necessary to over- lay the whole surface. This slightly affects the grade of the street by raising the same above the curb grade. Third, vulcanite has a more granular surface than the asphalt. Sheet pavements are sightly, pleasant to drive over, and easy to clean; but if not cleaned, as might be the case in this city, any accumulation of material would, from the nature of the surface, be ground to an impalpable powder, unpleasant to travelers and detrimental to lawns, the fine dust being blown into houses and stores. Such pavements would undoubtedly on business streets attract travel from parallel routes, thereby compelling the pavement of the latter with the same material, as a matter of self- defense, no matter what might be the ultimate value of the pavement. The mixture has to be nicely tempered, requires the satisfying of many condi- tions and expert manipulation. It is largely affected by temperature and climatic conditions. " In extreme cold the surface cracks and becomes fri- able ; in extreme heat the surface rolls or creeps under traffic, presenting a wave surface uncomfortable to travel over." In this connection I would state that the temperature at Washington ranges from 150 above zero in summer to 10 below in winter, or 160 Fahr., and Captain Griffin, United States Corps of Engineers, of that city, is authority for the statement that the Washington pavements suffer more during the three months of winter than during the remaining nine months of the year. The expense of laying foundations for street pavements is a large part of the total cost, and when the paving is worn out, or a city is tired of repairing the same, then the expense of removing the foundation will be large, as it is too near the established grade or curb grade to lay stone or other than sheet pavement on. It cannot be laid next to street-railway tracks, as it will not stand the shearing action of wheels. The science of laying sheet pavements is still to a large extent tentative. That good ones can be laid has been proven, but there is no certainty that the standard can be reached on any particular street ; two separate batches of material mixed under the same formula and specification may be totally unlike as regards durability. Standard of Comparison. In discussing sheet pavements a standard of comparison might be outlined as follows : First, moderate first cost ; 122 ASPHALT PAVEMENTS. second, durability ; third, minimum resistance to traction ; fourth, secure foot-hold for horses ; fifth, healthfulness ; sixth, noiselessness. Asphalt vs. Stone Pavement. First, sheet pavements do not satisfy the first requirement much better than dressed block ; second, I should give dressed block the preference as regards durability and ultimate cost ; third, the resistance to traction is undoubtedly less on sheet pavements ; fourth, such few experiments as have been made indicate fewer accidents to horses on sheet pavements than granite, but do not think it would hold good for Medina ; fifth, both sheet pavements and dressed blocks are healthy, and the asphalt filling of the latter sufficiently fulfills all sanitary requirements ; sixth, sheet pavements perhaps fulfill the last requirement better than stone, but there is the sharp click and ring of the horse's hoof, although the vehicle itself makes little noise. In making repairs in the case of a stone pavement 50 to 75 per cent, of the old material can be used over again ; it is worthless in the case of a sheet pavement. Finally, I consider sheet pavements a luxury, rendering any city attractive where successfully laid and maintained. , Their introduction should be simultaneous with the adoption of a continual repair system, to secure the best results. There is small choice between the asphalt and vul- canite pavements. I would advise against laying asphalt or vulcanite pave- ments on any of the thoroughfares of this city, and would further advise that the city should only consider its introduction as an original pavement and not on the repaving of any street. Further, if property-owners are desirous of obtaining these pavements, the city should, in my estimation, demand not less than ten years' guarantee, the pavement being turned over in good condition at the expiration of that period. REGARDING W. P. RICE'S REPORT ON ASPHALT PAVEMENTS.* NEW YORK, June 9, 1888. SIR : I have been reading the report of Mr. Rice, City Civil Engineer of Cleveland, quoted in your issue of May 26, on asphalt pavements in the United States, and in following this series I infer it is your purpose to pub- lish abstracts of official statements, whether you agree with the conclusions of the writer or not. With regard to this report of Mr. Rice, I think it is well to comment on some of his inferences and conclusions. Is not the following standard of comparison adopted by him for pave- ments viz.: "First, moderate first cost; second, durability; third, mini- mum resistance to traction ; fourth, secure foot-hold for horses ; fifth, health- fulness ; sixth, noiselessness," as set forth in your abstract of his report, susceptible of a better arrangement ? Pavements are primarily intended for the convenience of the inhabi- tants of those towns or cities which possess them, and the health of those who live beside them seems a consideration of the first importance. Put- ting moderate first cost and durability first would lead Mr. Rice, if a logical man, to clothe himself in a flannel shirt and stogey boots, articles of less first cost and greater economy in maintenance and repairs than those ordin- arily worn by persons in his position. Fortunately for the arguments of those who contend for good pavements, noiselessness and minimum resist- ance to traction are closely associated with healthfulness in pavements. For the nearest approach to a perfect pavement, in a sanitary view, seems ttxviii, 30. ASPHALT PAVEMENTS. 1 23 accomplished by a pavement which is impervious to fluids, presents no inequalities in which solid and fluid faecal or other matter can lodge, and admits of cheap and thorough cleaning. This evidently calls for a sheet pavement, for no block pavement is laid that is free from inequalities, and however well the joints are filled with concrete or a mastic of pitch or bitu- men, the filling in the joints will wear out faster than the stone, or even woodblocks wear, leaving shallow but numerous cavities to hold dirt and give off, at least, unpleasant exhalations under the heat of the summer sun, while all sheet pavements, on the contrary, when made either from asphalt or bitumen, are virtually non-absorptive ; that is, the small amount of water absorbed by asphalte comprime, or compressed rock asphalt, and pavements in which bitumen is the base, like those of Washington, is a mere matter of maintenance, having no sanitary influence whatever ; while pave- ments of asphalte coule, or the mastic made from rock asphalt, and those in which coal-tar is the basis, are free from this objection. Now these sheet pavements, in addition to their healthfulness, offer the minimum resistance to traction, are on the whole less slippery than any other except wood (excluding macadam), and are undoubtedly less noisy than any other pave- ment except wood. And there is another point which should not be over- looked : horses, besides doing more work, last longer, and there is less expense in repairing running gear and harness on these pavements than on any other. There is an apparent anomaly in this mater of pavements which your correspondent is able only to call attention to not to explain. Statisticians who make such subjects their study assert that the average income per annum in the United States is $200, in Great Britain and Ireland $150, in France $120, in Germany $100, and in Italy $80. Italy has long had the best maintained and constructed roads. Berlin, the capital of Germany, has better pavements than Paris, while that city until less than a decade since was decidedly better paved than London. But in New York, which may be regarded as the Capitol city of this country, one sighs for the quiet and repose of an active boiler-shop when the garbage-carts of the city pass through its best residence streets, and Philadelphia, the home of our oldest and stateliest families, has "pavements fanged with murderous stones," and in most of our cities one can count, in the words of Coleridge, "two-and-seventy stenches" " all well-defined and genuine stinks ! " any pleasant summer day ; while Washington, which has no productive or other business which is not par- asitic, has, considering its traffic, possibly the largest area of luxuriously and economically paved streets of any city in the world, and Buffalo has over forty miles of noiseless pavements. Washington, as is well known, aspires to have the position of the first residence city in our country, counting greatly on its pavements for help in reaching it. It might be suggested that Mr. Rice commenced his study of pave- ments without previous expert knowledge of this branch of the subject, or he would never have classed the compressed asphalt on the upper end of Pennsylvania Avenue with the pavement made of Trinidad bitumen on the lower part, or have failed to notice the rather peculiar outlines of the areas repaired in the compressed asphalt, so peculiar that persons unacquainted with the circumstances under which it was laid might have thought that the areas were denuded as a source of material for making asphaltic mastic. 124 ASPHALT PAVEMENTS. I But a little inquiry should have shown him that the pavement had been laid j on a foundation not sufficiently dry, and the hot powder had drawn steam / from the damp concrete on which it was placed, which prevented the adhe- sion of the powder so affected, resulting in macaroons, a disease which was prevalent in compressed asphalt pavements, till its cause was ascertained ; or, in other words, through the action of the steam, separate masses about the size of almonds, were formed under the smooth surface, produced by pillonage, which had no adhesion to each other. After three or four years these places had to be renewed, and the darker material in general use in Washington, which was used, gives, what otherwise would have been one of the finest pavements in any city, a very patchy appearance. It is rather surprising to see the statement that the shearing action of the wheels prevent its being laid next to street-railway tracks, as it is thought all specifications now provide for a toothing of granite blocks to be laid on each side of the track. But this toothing should extend so that the wheels of a wide-gauge truck should be supported by it. While omnibuses were running on Broadway, between Seventeenth and Twenty-third Streets, where one wheel was generally on the inside track, the outer wheel cut into the granite blocks at the rate of over half an inch a year, and it is absurd to suppose that a material, which must be more or less plastic, not to break up in the winter, can stand the concentrated action of heavily- loaded wheels without being pushed out of place. The frequent repairs now necessary on Chambers Street could be dispensed with if the toothing was carried over the outside tracks to cover the width of broad-gauge trucks. E. P. NORTH. ASPHALTE* PAVEMENTS IN PARIS.f = The following is an abstract translated from the specifications and instructions issued in 1884 by the Department of Bridges and Roads to contractors for roads and pavements in Paris : CHAPTER I. Object, Duration and Extent of the Enter prise, ART. i. Relates to the object and conditions of the work. ARTICLE 2. The work is divided into five divisions, not more than three of which will be awarded to one contractor. ARTICLE 3. Proposals for the first three divisions will be received only from contractors who have already successfully executed important work in compressed asphalt. The committee must be convinced that they pos- sess sufficient capital to assure the progress of the work during the period of the contract, and that they can furnish the specified brands of asphalt. The necessary brands and samples must be submitted to the committee one month before the award of the contract. ARTICLE 4. The duration of the contract is fixed at ten years, ending March 15, 1894. The amount of work is undetermined, depending on the funds applicable for its payment. The total annual expense is estimated at about i,ioo,ooofr. * All asphalte pavements in Paris are either asphalte comprimi! or asphalte couti, that is, the wheelways are paved with compressed asphalte, the rock being powdered, heated and pressed in place, and the sidewalks are paved with a bitumous mastic made of powdered rock asphalte which is melted by immersion in hot bitumen (often called "asphalt " in this country), sand and gravel being added to form a wearing surface. Crude bitumen is always refined by melting it in refined bitumen or shale oil, which acts as a flux. Heating the crude bitumen alone will burn it. ED. ASPHALT PAVEMENTS. 125 ARTICLE 5. The contractors must deposit in the municipal treasury, for the different divisions, a total security of 370,000 fr. If the security is in money, interest will be paid at three per cent. ; if bonds or deeds, the con- tractor may collect the income. ARTICLE 6. When the owners of adjacent property pay the whole or part of the cost of these works, the contractors must execute them in the same manner as for the city and under supervision of the same officers. CHAPTER II. Form and Dimensions of the Work. ART. 7. The width of the sidewalks for each locality will be determined by the Admin- istration, its slope by the engineer. The curb between the sidewalk and the roadway will not be included in this contract. ARTICLE 8. The pavements of asp halt e coule will be formed of a bed of natural bituminous mastic, melted with sand, at least 0.6 of an inch thick, resting on a foundation of hydraulic lime concrete 4 inches thick which is covered with 0.4 of an inch of hydraulic lime mortar. ARTICLE 9. The Administration reserves the privilege of making the asphalt roads on an old pavement whose surface will be redressed and coated with Portland cement to regulate the form. CHAPTER III. Quality and Brand of Materials Preparation of Bitumen and Asphalt. ART. 10. The asphalt rock must be a homo- geneous carbonate of lime, brown, fine grained, of a close texture, and uniformly impregnated with bitumen so as not to present black or white spots ; it must be free from iron pyrites, and not contain more than 2 per cent, of clay, and any portions producing less than 5 per cent, of bitumen will be rejected. The rock employed in the manufacture of compressed asphalt must be obtained from the mines of Val de Travers, Switzerland ; Volant, Upper Savoy ; Pyrimont, near Seyssel ; St. Jean de Maruejols, Gard ; or from other sources approved by the Administration. For the preparation of asphalte coule there will be accepted, besides the above, the products of Lovagny, Upper Savoy, of Dallay and Pont-du- Chateau, Puy-de-D6me ; and such other mines as give analogous mate- rials satisfactory to the Administration. ARTICLE n. The bitumen must be from the mines of Lussat and Malintrat, Puy-de-D6me ; or Maestu, Spain ; or from others having a simi- lar product acceptable to the Administration. The bitumen must contain no foreign substance, neither water, clay nor light oils. When maintained at a temperature of 250 Fahr.,for48 hours it must not lose more than 3 per cent, of its weight. It must be viscous at ordinary temperature, never brittle nor liquid ; when drawn out in threads it must elongate and only break in very fine points. Trinidad bitumen will be accepted if refined by melting and decanting in the contractor's shops in Paris. The necessary flux for this operation may be either fine natural bitumen from one of the above sources, or shale oil from the Autun slate, excluding gas-tar, the so-called fat bitumens and analogous products. The mixture of Trinidad bitumen and shale oil must be heated for eight hours, during the first six hours it must be vigorously stirred, but remain undisturbed during the last two hours in order to permit the impu- rities to fall to the bottom of the boiler whence they must be removed after each removal of the supernatant refined bitumen. 126 ASPHALT PAVEMENTS. The latter may be employed immediately for compounding the mastic or may be poured on suitable dry surfaces. The refined bitumen must not contain more than 25 per cent, of its weight of clay, and must be free from dirt, roots, etc. ARTICLE 12. The bituminous mastic employed for new pavements, and the repairs and renewal of old ones, will be composed of a mixture of powdered .asphaltic rock and mineral bitumen. The old compressed asphalte obtained by the removal of the old roads, may, if carefully separated from sand and all foreign matter, be substituted for the asphaltic rock; but artificial bitumen, gas-tar, fat bitumens and bitu- mens with a slaty base and all analogous products are rigidly proscribed. The asphaltic rock must be reduced, cold, in the most perfect mechan- ical crushers to the finest possible powder, which must pass through a sieve having meshes not more than o.i of an inch square. It will be melted and stirred for six hours with a suitable quantity of mineral bitumen, forming a mastic which, cooled, presents a homogeneous mass, slightly elastic and not softening at a temperature of 140 Fahr. This mastic must be molded in blocks bearing the maker's brand, its yield of bitumen must not be less than fifteen per cent, nor more than eighteen per cent, of the total weight. ARTICLE 13. The surfaces of asphalte coule of the first class must be formed of the mastic described in Article 12, of mineral bitumen, and of sharp sand, clean and dry, in the proportion of 100 parts by weight of mas- tic, four parts of bitumen, and sixty parts of sand. The sand, perfectly dry, will be successively added in the boiler to the melted mixture of bitu- men and crushed mastic blocks which must be stirred for at least eight hours. It is forbidden to make the bitumen in the movable boilers intended only for its transportation. ARTICLE 14. The Administration will permit in certain cases the sur- faces of asphalte coule to be composed of 100 parts by weight of new mas- tic, ten parts of bitumen, sixty parts of sand, and 170 parts of old bitumen from worn-out sidewalks, and carefully separated from all sand and foreign materials. The classification must in all cases be precisely stated in the bill accom- panying each load. ARTICLE 15. The powdered asphalte, mechanically crushed according to Article 12, must, when intended for the composition of asphalte corn- prime contain not less than seven per cent, and not more than thirteen per cent, of its weight of bitumen, the Administration reserving the right to fix the exact proportion according to the circumstances of the case and under the following conditions : 1. The rocks shall not differ except in their yield of bitumen, which must not be less than five per cent. 2. The pieces of rock must be mixed before crushing, or if mixed in the powdered state it must pass through the crusher again. The mixture of old asphalte from the removal of worn-out pavements with powdered new asphalte is forbidden. ARTICLE 16. The powdered asphalte must be raised to a uniform tem- perature of 248 to 266 Fahr. in rotators mechanically turned in a uniform and continuous manner which shall prevent adherence and burning. The apparatus must be of the most perfect type, and the powder must be maintained at the required temperature long enough to expel all watery vapo r . ASPHALT PAVEMENTS. 127 The use of machines called decrepitoirs is forbidden, either to reduce the rock to powder or warm the powder. ARTICLE 17. One month before the award the competitors must deposit in the Chief Engineer's office for each division of the public roads, and in the testing laboratory : (i) samples of asphalte rock and natural bitumen which they wish to use ; (2) blocks of mastic ; (3) samples of refined Trini- dad bitumen and shale oil ; (4) a statement of the composition of the mas- tics and the brands, compositions and proportions of the asphaltic rocks which they propose to use. The samples of rock and bitumen must bear the signature of the con- tractor and the maker's brand. During the period of the contract all materials used must conform to the samples deposited and bear the same brands. If it is wished to use other material they must be submitted to and accepted by the Administra- tion, and samples deposited. ARTICLE 18. 7 he sand will be dredged from the channel of the Seine above La Marne ; sand dredged opposite or below Paris will be rejected. Sand intended for the preparation of the surfaces of melted bitumen must be free from all earthy and foreign matter ; it must be sharp and dry, and separated by successive screenings from all grains less than 0.08 or more than 0.16 of an inch in any dimension, and conform to the samples deposited. Sand intended for mortar must be of the same kind and quality ; no grains must be larger than \ inch in any dimension. Sand from the seashore may be specially admitted if it is of first qual- ity, perfectly pure and well washed, and has been dredged, but a less price will be allowed for it than for sand from the Seine. ARTICLE 19. Gravel for beton must pass through a ring 2f inches in diameter, and must not be able to pass through a ring f of an inch in diam- eter ; it must be freed by abundant washing from earth and all foreign materials, and all round or smooth pebbles must be rejected or broken. ARTICLE 20. The lime must be hydraulic, powdered and delivered at the yards in sealed sacks, marked with the manufacturer's name, and pre- senting no exterior seams or patches. It must be provided from the kilns of Moulineaux, Mancelliere, Echoisy, Ville-sous-la-Ferte Raincy, Bougival, Coucou, or from some other source recognized as at least equally good. Vassy cement must come from the works of Grenan, Millot, Gariel, or Prevost. Portland cement must come from the works of Famchon, Boulogne-sur-mer ; or Quillot Freres near Lezinnes. The cement must be furnished in sacks, bearing the brand and seal of the works, the seal of the city, and presenting no external seams or patches. Any sack not satisfying the above requirements that is found in the yards will be immediately rejected and the contractor fined. CHAPTER IV. Execution of Work. ART. 21. The contractor will make the necessary excavations indicated by the grade marks placed for them. After the concrete is laid the iron or wooden grade stakes must be withdrawn and the holes immediately filled with concrete and mortar. When the excavation does not exceed two inches in depth, and the haul is not more than 100 feet, the excavations will be considered as simple surface dressing, whose payment is included in the price of the pavement above it. When the haul for such excavation is above 100 feet, payment will be allowed for transportation only. 128 ASPHALT PAVEMENTS.' All excavated material must be removed at the end of each day's work. If neglected by the contractor he will be charged with the cost of doing it, and fined for every cubic meter not promptly removed. ARTICLE 22. Existing sidewalk pavements must be demolished, and the materials either removed every night to the city storehouses, delivered to the adjacent property owner, or piled up for his disposition. Before tearing up the paving blocks they must be counted by the agent of the Administration and the contractor, who will be responsible for the recorded number, which he must deliver at the storehouse or be charged with the value of an equal number of new blocks of the same brand and pattern. The curbstones, crosswalks, etc., must be removed every night and placed at the disposal of the owners, or transported to the city storehouses by the engineer's orders. ARTICLE 23. The mortars must generally have the following propor- tions, by volume : Hydraulic lime mortar, 2 parts of powdered lime to 5 parts of sand ; Portland cement mortar, i part of powdered cement to 3 parts of sand ; Vassy cement mortar, 2 parts of powdered cement to 5 parts of sand. The Administration reserves the privilege of changing these propor- tions. For all important work, and wherever else required, the use of mixing machines will be obligatory for making all mortars not composed of quick- setting cement. The use of sewer water is forbidden for mixing mortar for which suitable pure water is required, that the contractor must take and pay for in the usual way. ARTICLE 24. Hydraulic lime and Portland cement concretes must be ordinarily composed of two parts by volume of mortar and three parts of gravel, rigidly measured in boxes whose capacity has been approved. The gravel will be brought in wheelbarrows to a grating, where it will be abundantly washed in clear water. The mixture must be thoroughly worked by a rake and shovel on a plank platform of sufficient size, until all the stones are completely enveloped in mortar. For Portland cement beton sufficient water must be added to make the mixture suitable for use in a fluid state. ARTICLE 25. The ground over which an asphalte coule pavement is to be made must first be loosened, then sprinkled and carefully rammed, especially along the border. When the soil has thus been solidified and well dressed, the contractor must establish the foundation bed, formed of hydraulic lime concrete 4 inches thick, including a coat of \ inch of lime mortar. The concrete must be carefully rammed to close all open spaces and make the mortar overflow the surface, after which the surface will be immediately regulated to the required profile. The bitumen pavement will not be made until this foundation has set and is well dried ; meantime the surface of the foundation will be protected by a bed of fine dry sand, which will be carefully swept off before the application of the asphalte coule. Watchmen and barriers against traffic must be maintained at the contractor's expense. ARTICLE 26. The asphalte coule, prepared as above required, must be quickly brought from the shops in closed locomotive furnaces, warmed and ASPHALT PAVEMENTS. 129 supplied with suitable apparatus to continue the mixing during transporta- tion and up to the moment of application, so as to maintain intimate mix- ture and prevent direct action of the fire. It must not be prepared in fixed furnaces at the points where it is used, when not otherwise specified. The coat of bitumen will be 6 inches thick ; it will be poured in sections about 6 feet wide, perpendicular to the curb, and limited by iron rules of the required thickness. The asphalte coule will be spread by means of a wooden float in such a manner as to form a perfectly dressed surface without lumps or hollows. Each new section must be perfectly welded to the preceding in such a manner as to present no open joints, cracks or offsets. The mastic must have no cavities, must be level and exactly match all curbs, gutters, paving, man-hole covers, tree boxes, hydrants, etc., and join the house walls without any cracks or cavities. In constructing isolated sections the concrete foundation must extend one inch each side beyond the mastic, which will be limited by regular lines. As soon as completed, the surface will be lightly sprinkled with fine dry sand and gravel, no grains exceeding one-eighth inch, nor being less than one-twelfth inch in diameter. It is absolutely forbidden to throw water on the surface while it remains warm. Before admitting traffic, the contractor must barricade and guard the pavement and protect it until it is able to sustain the passage of pedestrians. The barrier posts and pickets must never be driven into the pavement* but must be supported by plaster bases. ARTICLE 27. Asphalte Pavements. The ground on which the asphalt, is to be placed must always be first loosened, then sprinkled and carefully rammed, particularly along the curb. The Administration reserves the right to roll it at its own expense.* When the soil is thus sufficiently consolidated and well dressed, the- contractor will make the foundation bed, generally formed of Portland cement concrete, six inches thick, but always subject to the requirements, of the Administration, who may augment or diminish the thickness or pre- scribe the use of hydraulic lime in certain cases. The concrete foundation must extend with the same thickness, six inches under the curb, and four inches behind its rear face. And the con- tractor must, if required, set the curbs in the concrete in a mortar bed at the same time that the road foundations are made. Stone and other materials must be transported on planks over the con- crete foundation. Wheelbarrow loads of concrete must not be emptied directly on the soil, but on the work already finished, and afterward spread into the required position, and rammed until the mortar flows to the surface, which will then be carefully regulated to the required curve and immediately covered with a coat of Portland cement mortar about one-half inch thick, that will be smoothed and cannot be replaced by a coating made at a later time. The concrete must be left to dry and set for the longest possible time, in every case, during at least three days in dry and five days in wet weather ;. meantime the contractor must provide barriers and watchmen to protect the. work. 130 ASPHALT PAVEMENTS. Immediately after it is laid, the concrete foundation must be protected by a thin bed of very fine sand, which will be carefully swept off when the asphalt is applied. The Administration reserves the right to have the asphalte roads built on rolled stone foundations, whose surface shall be cleaned and receive an evening coat of Portland cement mortar. ARTICLE 28. The powdered asphalte, heated and prepared, must be brought to the required point in covered carts, of a pattern approved by the Administration, and designed to prevent, as much as possible, the cooling of the material during transportation. The powder must be spread about two-fifths thicker than the required two inches. It will be brought in special wheelbarrows, trundled on planks over the foundation bed. The powder will be leveled wdth a rake, and all foreign material carefully removed, and it will be carefully rammed, with increasing energy, by cast rammers, properly warmed in movable furnaces. The ramming will be commenced at the edges, and must be conducted so as to assure complete union between adjacent bands, and exact junction with the edges of the pavement limiting the asphalte surface. After being twice rammed, the pavement must be smoothed by a suitable curved hot iron tool, after which it must be vigorously rammed and rolled until thoroughly cold, by a roller of at least 1,100 pounds weight. The cooling must not be hastened by the application of cold water. The operations must be conducted so as to secure a perfectly uniform bed of asphalte, with a surface rigidly conforming to the required profile and presenting no lumps or hollows. The pavement will be sprinkled with sand and not opened for traffic until thoroughly cool, until which time the contractor must protect it by barriers and watchmen. ARTICLE 29. The above requirements apply to the construction of carriageways, footways, and analogous works, and to the maintenance of repairs of junctions of drains, etc. Carriageways constructed by special order must have, when made of asphalte coule, a foundation of hydraulic lime concrete 6 inches thick, including the mortar surface, and covered with two coats of asphalte coule 0.6 inches thick, successively poured, the second one being checkered. When made of asphalte the carriageways must have a foundation of Portland cement concrete 6 inches thick, covered i^ inches thick with a bed of compressed asphalte. ARTICLE 30. Within three months after the award of the contract the contractor must distribute furnaces for use in repairing the asphalte coule. These furnaces must be provided with boxes to contain the old materials removed from the road. Similarly, for asphalte repairs, the carriages bringing the hot powder must contain one closed compartment for the heated powder, another for the grate, fire, irons and the tools necessary for making the repairs, and a third to carry the debris and material resulting from the demolition of the old pavement. After each operation of new work or repairing, before returning the furnaces to the shop their site must be carefully swept and cleaned of ashes, coal, debris, etc. CHAPTER. V. Maintenance, Under Forfeit, of the Sidewalks and Areas. ART. 31. The contractor is required, ist, to make all necessary repairs and removals, and furnish the labor and materials requisite to main- ASPHALT PAVEMENTS. 131 tain the sidewalks and asphalte and asphalte coutt areas in perfect con- dition, and to maintain all paved gutters included in the given district. 2d. To repair yearly, equal to new, at least the fifteenth part of the asphalte coult areas. 3d. To repair yearly, equal to new, such parts of the asphalte areas as are designated by the Administration. This comprises repairs due to any cause whatever, except those necessitated by trenches dug by the city or by private or public companies. The contractor is not entitled to extra payments for loss or expense from any unforseen circumstance or condition. ARTICLE 32. Each year, before March 15, the contractor must present to the Administration a statement of the surface to be repaired, this state- ment, subject to modification by the Administration, must be conformed to by the contractor; if it is not presented by him it will be prepared by the engineer. One-half of the asphalt coule repairs rnust be completed by July i, two-thirds must be completed by August 15, and they must be entirely finished by October i, and the contractor will be liable to a reten- tion of payment if the work is delayed beyond these dates. The repairs implicitly comprise the demolition and removal of the old asphalte cotile which belongs to the contractor, and the rectification and repairs, if necessary, of the old foundation. The asphalte coule surface must .be perfectly plain and regular, with- out humps or hollows, and so that a straight edge, i.o m. long (3.20 feet), laid in any direction will not leave an opening more than 0.4 inch deep be- tween its side and the pavement at any point. There must be no holes nor cracks in the surface. Throughout the ^f ms. of asphalte coule surface not specially repaired, the contractor must renew all places where the surface is cracked, split, depressed, swelled, or in any way perforated, where it matches imperfectly with tree boxes, fountains, man-holes, etc., and especially where sunken near trenches and fountains. It is formally stipulated that in repairs of the first fifteenth of the sur- face, only asphalt of the first class can be used; in other repairs asphalt of the second class may be used. ARTICLE 33. Repairs of Asphalte Surfaces. The requirements are substantially the same as those of Art. 32, excepting the last clause, and it is further specified that when the foundation is found defective, the Admin- istration may require it to be replaced with Portlant cement concrete. Defective spots must be carefully cut out with a sharp hatchet and at least 1.67 feet larger in every direction than the defective place; the sides must be cut on straight lines; there must be a perfect union of the old and new material, and the surface must show no irregularities. On September i, or sooner in case of bad weather, a general examina- tion will be made with the contractor, who must immediately begin repairs on doubtful surfaces not likely to endure through the winter. In rainy weather the bottoms of the patches should be sponged and dried as carefully as possible with fine hot ashes, and then be well brushed. Special care must be taken to clean all sand, powder, etc., from the bottom of the patches. If the concrete is reached it must be entirely renewed underneath the patch, or a Portland cement dressing be laid on top, flush with the bottom of the patch throughout. 132 ASPHALT PAVEMENTS. During bad weather no repairs shall be made of asphalte, unless ex- pressly authorized by the Administration. Melted bitumen, which may be of the second class, will generally be used for a bed for the patch. The patch is only temporary, and must be replaced by the i$th of May, or sooner, if possible. The contractor is absolutely forbidden to use pebbles for filling holes in the asphalte. When the contractor fails to make necessary repairs, and the Administration, exceptionally and in default of other available means, fills holes with broken stone, the contractor must pay for the work and ma- terials, and cannot claim damages for injury to the pavement caused by the loose stones. In winter, when the Administration recognizes the impossibility o making lime or cement concrete, holes in the foundation that is to be repaired may be filled by a mixture of three parts by volume of pebbles to one part of hot asphalt^ but this provisional foundation must be removed as soon as possible and replaced in the standard manner, and this bituminous material cannot be re-employed. All repairs must be made with new pow- dered asphalt, the same as for new work. ARTICLE 34. Relates to statements, estimates and payments for the work done. ARTICLE 35. Relates to the measurement of surfaces, etc. ARTICLE 36. Relates to the prices and payments for the different classes of work. ARTICLE 37. The contractor will be paid for repairs at sewer trenches, water and gas conduits, etc. He can make no claim for settlement or other injury at these places, and must maintain the pavement there in the same condition as elsewhere. To assure a perfect welding at the edges of the asphalte coule or the asphalte it will be paid for of a width 2 inches greater in every direction than the trench, and must not fall short of these dimensions. To provide for earth settlements the contractor may temporarily main- tain these areas during a period of not more than eight days with broken stone, 2^ inches in diameter, that is rammed, sprinkled, swept and main- tained, so as to prevent injury from loose stones. After eight days, if final repairs are still impossible, the contractor must, at his own expense, make a provisional surface six inches thick of bituminous concrete, to be removed for final repairs. All old materials taken from trenches, and all abandoned depots, must be removed the same evening. CHAPTER VI. General Conditions and Regulations. ART. 38. Relates to the inspection and acceptance of materials and work. ARTICLE 39. Relates to extra payments. ARTICLE 40. The contractor must remove at his own expense, and buy at schedule prices, all the asphalte provided by demolishing the old work. No allowance will be made for the nature or condition of the materials. The asphalte and asphalte coule will be bought by the square meter ; the price of the former will be according to the mean thickness, and for the latter will be uniform for all thicknesses. ARTICLE 41. Relates to transportation of material. ARTICLE 42. Relates to the inspection, testing, marking, etc., of materials and work. ASPHALT PAVEMENTS. 133 ARTICLE 43. The contractor must provide at his office and shop, a tele- phone for the use of the engineers in special cases, and to give them notice of the exact hour when their presence is required ; the telephone must be connected with the general system and have an attendant capable of receiv- ing and transmitting orders and messages. ARTICLE 44. Relates to police regulations, numbering, marking furnaces, etc. , and unloading materials. ARTICLE 45. The contractor is forbidden to burn any material in his furnaces that will cause disagreeable fumes, discolor the paint on adjacent houses, or injure the neighboring vegetation, and the furnaces must be placed so that the smoke will be carried as little as possible by the wind to adjacent gardens or parks. ARTICLE 46. On holidays or exceptional occasions, the Administration may require the contractor to cease digging or depositing materials in the street, and he shall be entitled to no damages therefor or extension of time on account of such delays. ARTICLE 47. In an urgent case the contractor may be required to estab- lish a night-turn, for whose labor he will receive 50 per cent, above the regular schedule price, during that time only which is specified by the Administration . ARTICLE 48. Any employee not obeying the engineer's orders, or who practices any fraud or disobedience of the regulations, must be immediately discharged by the contractor at the engineer's request. Payments will be retained for any portion of the work badly or fraudulently executed by the contractor's agents, and such work must be renewed before it cfan be esti- mated. If an employee is not immediately removed when required, all work done by him will be subject to a double penalty and will not be estimated. The contractor must furnish a certificate showing cause for leaving, to every employee who leaves any department of his municipal work, and this certificate must be immediately submitted to the engineer, who may refuse to permit re-employment, ARTICLE 49 provides that if the contractor is absent without authority, fails to perform all his duties, or to obey the injunctions of the Administra- tion within ten days, he shall be notified that he is considered to have abandoned the undertaking, and after twenty-four hours the Administra- tion may either prescribe a re-letting of the old contract or may entirely cancel it without returning the material ; or it may execute the work at the expense of the contractor, by workmen under competent supervision, or with contracts by private contractors, according to the urgency of the case. The expenses will be covered by the amounts due the contractor, and by the contractor's deposit in the city treasury. ARTICLE 50. The contractor is forbidden to sublet any part of the work without the written authorization of the engineer, which authorization is always subject to revocation. It is especially prohibited to sublet the digging and transportation to a different party from the one who furnishes and constructs the concrete foundations. ARTICLE 51 requires that the contractor provides a responsible agent for each division of the work ; that the contractor and his agents must per- sonally meet the engineers at any time they may appoint, and relates to the Tegular reports, receipt of instructions, etc. 134 ASPHALT PAVEMENTS. ARTICLE 52 is a schedule of amounts to be retained by the Adminis- tration from the payments due the contractor, in cases of fraud, delay, imperfect work or materials, etc. For the use of unauthorized or impure asphalte, each offence, soof.; for the omission of new concrete where required under patches, $of . ; for delaying the repairs of T ^ of asphalte coule, from loof. to soof. For delaying repairs of asphalte, from 2oof . to soof. ; for delaying to commence work ordered begun, 2of. per diem. Other fines are specified for insufficient thickness in pavement and foundations thereof, for the use of improper and insiifficient material, for poor or improper workmanship, for unsatisfactory illumination and protec- tion, for various delays and insufficient progress, etc., etc. ARTICLE 53 provides for the regular reports of the engineers, which must be countersigned by the contractor. Provision is made for settling disagreements between the contractor and engineer and for paying the former, if necessary, from the deposit in the treasury. ARTICLE 54. The schedule prices for the different parts of the work will be held invariable. ARTICLE 55. The contractor must, at his own expense, properly light, barricade and guard the work and shops, conforming to police regulations and special instructions from the engineers. An inclosed lamp or lantern must be placed at least every 10 meters (33 feet) along the working place, which must have red lights toward the open road. ARTICLE 56. One per cent, of all sums due the contractor will be reserved for the benefit of the national asylums of Vincennes and Vesinet. ARTICLE 57. The contractor must pay the contract and registry fees, and at the expiration of the guaranteed period will receive his deposit, less any deductions that may have been incurred. ASPHALT PAVEMENT CONTRACTS IN NEW YORK,* During the past few days, the New York Evening Post has, in double column articles with conspicuous head lines, published attacks on Public Works Commissioner Gilroy, of New York, alleg- ing improper conduct in the matter of letting contracts for asphalt pavements, and intimating this was with a view of favoring adherents of the political organization known as Tammany Hall, of which he is a conspicuous leader. The charges are, substantially, that a pavement, except in one instance, was called for that one cor- poration practically controlled ; that the price paid the contractors on this work was exorbitant, and that the bond exacted to guaran- tee the 1 5-year maintenance, though 25 per cent, of the contract price, was insufficient. Seventy per cent, of the contract price was payable on the completion of the work, and 3 per cent, of the remain- ing 30 per cent, being payable yearly for ten years after the first five years. *xxi, 98. ASPHALT PAVEMENTS. 135 We are satisfied that he honestly tried to get the pavement that he believed was the best, and that he acted on the advice of those whom he believed competent to advise and who had no interest in any particular pavement. In regard to the cost, the Post quotes Mr. Gilroy's statement that the average price of the contracts is $4.45 per square yard, with a i5-year guaranty, while the ruling price in Washington for several years has been $2.25 per square yard, and urges that there is no good explanation for the difference. The pavements in the two cities are laid by the same concerns in the same way, and are sub- stantially alike. Of course it might happen that New York paid too much, relatively, without dishonesty of its officers, but as a matter of fact there is obvious explanation for a considerable difference in price between the two places. The cost of labor, including teams, is in the region of 30 per cent. less in Washington than in New York, and in the first named place the refining plants are within the city and in hauling and handling material there is a large advantage over New York. Again, Wash- ington is a city of very light traffic and the cost of maintenance is small, while in New York it will form a heavy item. The general theory in the last named city is that asphalt pavement will need but slight repairs for the first five years in residential streets, but after that it will cost from 10 to 15 cents per square yard per year to keep it in order. This, with the fifteen year contracts, of course involves a charge of from i to 1.50 a square yard in the price. This is put in the contract price for paving instead of being made directly in the shape of future payments for maintenance, it may be remarked* because of a provision in the laws forbidding contracts for payment of money not already appropriated. Of course the proper difference in cost of the pavement at Washington and New York can be only approximated, but the facts and figures given at least show that it is considerable. The Post contended for a bond of more than 25 per cent, of the contract price, yet the fact that it was put even so high effectually excluded many parties from bidding, simply because they could not find capitalists who were willing to wait fifteen years to be released from an obligation. It should be clear that if the bond was higher the competition would be more restricted and the price greater. It seems to us the bond is sufficient. The people of New York certainly have manifested a desire for asphalt pavements on streets for which it is suited, and Mr. Gilroy should not be charged with improper conduct in asking for what he was advised and had satisfied himself had been satisfactorily tried elsewhere, especially since his specifications called for no pavement 136 ASPHALT PAVEMENTS. that one company has a monopoly of putting down. This is shown by the fact that contracts were awarded to the Barber Asphalt Pav- ing Company and Matthew Taylor, rival concerns, to the amounts of $325,287 and $256,590, respectively. In our opinion the average price of $4.50 per yard, on a -inch concrete foundation, involving as it does a fifteen-year maintenance, was a low one to be made with responsible guarantees. ASPHALT PAVEMENTS OF BUFFALO, N. Y.* Buffalo has a large number of its principal streets paved with asphalt. We, therefore, obtained from the city engineer copies of the specifications under which these pavements were laid. Deputy City Engineer Edward B. Guthrie informs us that under the " Barber Specifications," which we reprint below, about 50 miles have been laid since 1882, and the experience has been satisfactory to the citizens and the municipal authorities. Besides this a con- tract has been made for five miles of vulcanite pavement this year under a five years' guarantee, which is being laid under the specifi- cation also reprinted below. A. L. Barber s specification for laying his genuine Trinidad asphalt, pavements ; 1888. i. We propose to lay Trinidad asphalt pavements two and one-half (2)4) inches in thickness when compressed, with a base of hydraulic cement- concrete six inches in depth. Roadway. 2. All unnecessary material will be removed from the street; soft or spongy places, not affording a firm foundation, will be dug out and refilled with good earth, well rammed, and the entire road-bed will be thoroughly rolled. Foundation. 3. Upon the road-bed thus prepared will be laid a bed of hydraulic cement-concrete six inches in thickness, to be made as follows: One measure of American cement, equal to the best quality of freshly- burned Rosendale cement, and two of clean, sharp sand will be thoroughly mixed dry, and then made into a mortar with the least possible amount of water; broken stone or brick, thoroughly cleaned from dirt, drenched with water, but containing no loose water in the heap, will then be incorporated immediately with the mortar in such quantities as will give a surplus of mortar when rammed. This proportion, when ascertained, will be regulated by measure. Each batch of concrete will be thoroughly mixed. It will then be spread, and at once thoroughly compacted by ramming until free mortar appears upon the surface. The whole operation of mixing and lay- ing each batch will be performed as expeditiously as possible. The upper surface will be made exactly parallel with the surface of the pavement to be laid. Upon this base will be laid the wearing surface, or pavement proper, the cementing material of which is a paving cement prepared from pure Trinidad asphaltum, unmixed with any of the products of coal tar. *xix, 60. ASPHALT PAVEMENTS. 137 Wearing Surface. 4. The wearing surface will be composed of: Asphaltic cement from 12 to 15 Sand " 83 to 70 Pulverized carbonate of lime " 5 to 15 IOO IOO i In order to make the pavement homogeneous, the proportion of asphaltic cement must be varied according to quality and character of the sand. The carbonate of lime may be reduced or omitted entirely when suitable sand can be obtained. The sand and asphaltic cement are heated separately to about three hundred degrees Fahrenheit. The pulverized carbonate of lime, while cold, is mixed with the hot sand in the required proportions, and is then mixed with the asphaltic cement at the required temperature, and in the proper proportions, in a suitable apparatus, which will effect a perfect mixture. The pavement mixture, prepared in the manner thus indicated, will be laid on the foundation in two coats. The first coat, called cushion coat, will contain from 2 to 4 per cent, more asphaltic cement than given above; it will be laid to such depth as will give a thickness of half an inch after being consolidated by a roller. The second coat, called surface coat, pre- pared as above specified, will be laid on the cushion coat; it will be brought to the ground in carts, at a temperature of about 250 Fahr. ; it will then be carefully spread, by means of hot iron rakes, in such manner as to give a uniform and regular grade, and to such depth that after having received its ultimate compression, it will have a thickness of two inches. The sur- face will then be compressed by rollers, after which a small amount of hydraulic cement will be swept over it, and it will then be thoroughly com- pressed by a steam roller; the rolling being continued as long as it makes an impression on the surface. Should there be a railroad track on the street, the edge of the asphalt pavement adjacent to the track will be protected by a line of stone paving blocks on each side of the rail. SPECIFICATION For paving with "A. L. Barber's Trinidad Asphalt Pavement," including all necessary connections as per specifications and quantities given : The carriage-way shall be graded two (2) feet wider than the width of the pavement ordered and to a depth of eight and one-half in ches below the surface of the street on the centre line, the cross-section to conform to a crown of . . . .inches, in accordance with stakes set for line and grade by the engineer, or person appointed. Roots of trees, when so directed by the engineer, to be saved as much as possible, and grading to be done carefully around said trees ; also the sodding on sidewalks to be protected as much as possible, if the street is to be graded only for the width of the paving. The sidewalks are to be graded, if petitioner the order for paving this street includes the grading of sidewalks, with a rise of one-half (^) inch per foot from the top of the curb-stone to the side of the street. Wooden or stone sidewalks must be removed carefully and must be replaced in front 138 ASPHALT PAVEMENTS. of each lot where they originally belonged, in as good a shape and manner as they were found by the contractor before removing them in order to grade the street. All embankments shall be thoroughly settled before any sand or gravel or concrete for paving is laid on them. The contractor (if necessary) must flood the entire bed of the sub-grade with a sufficient quantity of water r provided the water-pipe lays on the street, after excavation to proper sub- grade, and must pound well all spots that show a depression by being flooded. The cost of the water the contractor must include in his contract price. The width of paving between the curb-stones is to be feet. The curb-stones to be 1 of the best quality of hard Medina sandstone, not less than four (4) inches thick and eighteen (18) inches deep, not less than two (2) feet six (6) inches long, cut with a proper bevel on the top to a true and uniform surface. The end joints are to be cut at right angles with one-quarter () inch joint for a depth of ten (10) inches. The face of the curbing from top to the under side of the asphalt coating must be neatly dressed. The curbing must be carefully set to straight line and a true grade in a full bed of sand or gravel, and backed up with eight (8) inches thickness of same m'aterial in the rear. At crossings of paved streets, connections of curbs must be made at corners with a true circle of six (6) feet radius. Protection curbing to be not less than three (3) inches thick on top, and dressed to uniform width on top, with end joints cut at right angles not to exceed \ inch for a depth of at least three (3) inches, to be not less than eighteen (18) inches long and fourteen (14) inches deep, and to be hard Medina sandstone. The gutters shall be of a depth of. . . inches, or as shall be directed. The asphalt pavement to be laid in accordance with the specification for A. L. Barber's Trinidad asphalt pavement, hereto attached. Where the curbing comes above natural ground, it must be backed up by a bank. . . .wide on top, rising \ inch per foot towards lines of street, with a slope to natural ground near lines of street of i to i. Where such banks come on stone or wooden sidewalks, these must be first carefully taken up and properly relaid on top of bank in front of each property, where they originally belonged, as to be directed. General Specifications. All material found in the grading of the street, except sidewalks proper, hitching or other posts, step stones or other private property, is the property of the contractor; also all chips, stones, rubbish, etc., that may have accumulated on the streets or sidewalks during the process of paving, and after completion of grading and paving the street, block after block, as the work progresses, must be removed therefrom by him. All old material found in the street, that after being properly redressed corresponds in reference to size, shape and quality to these specifications, may be used in the new work. All material furnished and all work done, which, in the opinion of the engineer, shall not be in accordance with these specifications, shall be immediately removed, and other material furnished and other work done that shall be in accordance therewith. In preparing concrete, none but coarse, sharp, clean sand will be allowed. ASPHALT PAVEMENTS. 139 The work shall be done subject to the inspection and approval of the engineer, or such person as appointed, both as to material and workman- ship, and must be completed in working days, after a written notice from the engineer to begin the work has been served on the contractor. The work shall be deemed complete when the contractor is allowed the final twenty per cent, on his contract. The contractor to be subject to a. penalty of $ for every succes- sive day after the above specified time until the work is completed and accepted, unless otherwise ordered by the Common Council. The engineer, or such person as appointed, will set the stakes for paving, provided a block has been properly excavated, to sub-grade from curb line to curb line of cross street, for line and grade, which the contrac- tor must protect and maintain and keep uncovered for examination. The contractor shall pay all damages, or losses, or claims recovered, that the city may be made liable for, and save the city harmless in all things, from any accident which may happen or arise by reason of failure, or neglect, or refusal on his part to comply with the ordinances of the city. In the event that the contractor shall abandon the work and refuse to commence it again within three (3) days after a written notice from the engi- neer, directing him to resume the work, has been served on him, then the sureties on the contract will be notified and directed to complete the work. The contractor will be required to pile all material that may be neces- sary for the work neatly on the front of the sidewalk, and not within three (3) feet of any fire hydrant, and in such manner as will preserve sufficient passageway of not less than three (3) feet on the line of the sidewalk. The contractor must accept orders for extra work, not included in this contract, which may be necessary and connected with the paving of the street, if so directed by the engineer, and execute them properly at reason- able prices. He must make sewer and water connections where ordered, in accordance with attached specifications for same, to be paid for as stated in said specification, at prices not to exceed the ones given below. Each proposal must state a certain sum for furnishing materials, labor, and finishing the work complete ; it must be accompanied by bonds required by law; it must include the sum of $ per day for the purpose of paying an inspector, to be appointed by the engineer, to super- intend the paving during the entire time the work is progressing ; said inspector to be paid on the recommendation of the engineer, by warrants drawn against the assessment roll for said work. The inspector shall not be employed in any manner by the contractor, and shall be discharged at the option of the engineer. The orders of the inspector are to be obeyed by the contractor, or in absence of the latter by the superintendent. In case the city finds it necessary to lay pipes for gas or water, or make other improvements in the street, or private parties or companies want to make connections with pipes laid in the street, or want to make repairs or adjustments of their pipes, stop-cocks, etc., before the concrete bed for paving is made in any one place, the contractor shall not interfere with the progress of such work, but any time lost by him on account of the city, private parties or companies making such improvements, etc., before paving, will be added to the time allowed to him to, finish the work com- plete. 140 ASPHALT PAVEMENTS. The contractor is obliged to be either himself at the work, or in his absence, to have a foreman present at the work, who will be responsible for the whole work under contract, and who must obey the order of the engi- neer or his assistant in relation to every part of work to be done under their contract. The contractor agrees that he will pay, punctually, the workmen who shall be employed on the aforesaid work, in cash current, and not in what is denominated store pay, And that all laborers to be employed on the said work shall be paid at the rate of not less than one dollar and fifty cents per day of ten hours' work. (SECTION 39.) "No contract for the pavement of a street or avenue, or any part thereof, shall hereafter be let or made until the person or corporation to whom it is proposed to let the contract shall furnish a bond to the city of Buffalo, with two sufficient sureties, who shall each justify in full penalty of the bond. The condition of said bond to be that the contractor will, at his own cost and expense, keep and maintain the pavement in good condition for five (5) years from the completion of each pavement. Said bonds shall be approved by the Mayor, and filed with the Comptroller, and the amount of said bond to be equal to 33^- per cent, of the contract." According to above section 39, chapter 3, the contractor binds himself to repair the street during said five (5) years whenever and wherever and in the manner as directed by the engineer within five (5) days after a written notice to that effect is served on him ; and in the event that the contractor refuses or fails to comply with such order of the engineer, then the sureties of said bonds will be notified and directed to proceed with the repairs as directed by the engineer. He further binds himself to repair the street only on the order of the engineer. Payments will be made semi-monthly, according to an estimate of the engineer, of work completed and material delivered within twenty (20) per cent, to be drawn from the proper fund ; said twenty (20) per cent, to be retained until the work is completed and accepted by the engineer in legal form. In accordance with a resolution adopted February 7, 1887, all curb, crosswalk and other cut stone used in the paving of this street must be cut within the city limits. Specifications of Connections. Proper connections have to be made with all asphalt or stone pavements abutting to or crossing this street. The asphalt connections have to be made either according to "A. L. Barber's Asphalt Specification " or according to the kind of asphalt laid on these streets previously as to be directed. The stone pavement connections must be made according to the .... class pavement specification, with the exception that excavation below is not required, but all necessary sand and stone is to be furnished by the contractor to fetch such repavement to proper grade and quality as to be directed. The quantities for excavation and filling include all connections of unpaved cross streets, at a rise or fall of one foot in thirty- three, and for a width as to be directed in each case ; also all openings of gutters on said unpaved crossing streets, or other streets, where, and as far as necessary, as directed by the engineer. ASPHALT PAVEMENTS. 14! The wooden or other crosswalks, where disturbed by grading said dirt street, must be carefully relaid in as good condition as they were before, at each crossing where they originally belonged. Quantities. Excavation, cub. yards ; embankment, cub. yards ; new curbing, lin. feet ; protection curbing, lin. feet ; old curbing reset, lin. feet ; length of street to be paved, lin. feet ; new gutter, sq. feet ; old gutter reset, sq. feet . . . ; new crosswalk, sq. feet ; old crosswalks relaid, sq. feet ; new paving, sq. yards ; re- paving with more or less old material, asphalt, sq. yards. . . . ; repaving with more or less old material, stone, sq. yards. . . . ; round corners. . . . ; connec- tions with sidewalks. . . . ; inspector per day, $. . . . Engineer. Specifications of the Filbert Vulcanite Asphaltic Pavement, laid by the National Vulcanite Company of New Jersey. 1. The vulcanite asphaltic pavement will be eight and one-half (8) inches in thickness, as follows : The wearing surface will be one and one- half (i) inches in thickness when compacted, with a bituminous base and binder seven inches in depth. 2. The space over which the pavement is to be laid will be excavated' to the depth of eight and one-half (8|) inches below the top surface of the pavement when completed. Any objectionable or unsuitable material below the bed will be removed, and the space filled with clean gravel or sand well rammed. The bed will then be trimmed so as to be exactly parallel to the surface of the new pavement when completed, and the entire road-bed will be thoroughly rolled with a heavy steam-roller. Upon the foundation will be laid the base and binder, seven (7) inches in thickness, in the following manner : 3. The " base " will be composed of clean broken stone, that will pass through a three (3) inch ring, well rammed, and rolled with a steam-roller to the depth of five (5) inches, and thoroughly coated with hot paving cement, composed of No. 4 tar distillate in the proportion of about one (i) gallon to the square yard of pavement. 4. The second or "binder" course will be composed of clean broken stone, thoroughly screened, not exceeding one and one-quarter (i) inches in the largest dimensions, and No. 4 tar distillate. The stone will be heated by passing through revolving heaters, and thoroughly mixed by machinery with the distillate in the proportion of one gallon of distillate to one (i) cubic foot of stone. 5. The " binder " will be hauled to the work, spread upon the base course at least two (2) inches thick, and immediately rammed and rolled with hand and heavy steam-rollers while in a hot and plastic condition. 6. The wearing surface will be one and one-half (1*4) inches thick when compacted, made of paving cement, composed of twenty-five (25) per cent, of asphalt and seventy-five (75) per cent, of distillate mixture, with other materials, as follows : Clean, sharp sand will be mixed w y ith pulver- ized stone of such dimensions as to pass through a one-quarter (*^) inch screen in the proportion of two to one. To twenty-one (21) cubic feet of the above named mixture will be added one peck of dry hydraulic cement, one quart of flour of sulphur, and two quarts of air-slacked lime. To this mixture will be added three hundred and twenty (320) pounds of paving cement, to compose the wearing surface. I 42 ASPHALT PAVEMENTS. 7. The material will be heated to about 250 Fahr. the paving cement in kettles, the sand and stone, etc., in revolving heaters. They will be 1 thoroughly mixed by improved machinery, and the mixture carried upon the work, when it will be spread upon the binder course two (2) inches thick with hot iron rakes and other suitable appliances, and immediately compacted with tamping-irons, hand and steam rollers, while in a hot and plastic state. The surface will be finished with a dusting of dry hydraulic cement rolled in. 8. The pavement so constructed must be a solid mass, eight and one- half (8}4) inches thick, and will be thoroughly rolled and cross-rolled until it has become hard and solid. 9. The pavement shall be equal in every respect to that laid on K Street, between Ninth and Eighteenth Streets, N. W., Washington, D. C., in 1874 and 1875. ASPHALT PAVEMENT ON STONE FOUNDATION IN NEW YORK.* The following specifications for the particular kind of pavement required is of interest, since they are prepared by the Department of Public Works, presumably after careful investigation, it being re- "membered that for the expenditure of the $3,000,000 appropriation for new pavements, a special engineering department has been created, with Stevenson Towle, M. Am. Soc. C. E., as engineer in charge. Specifications for Laying an Asphalt Pavement on the present Stone- block Pavement in Park Avenue, between Thirty-fourth and Fortieth Streets, New York City. 1. Work and Materials must Agree 'with Specifications. All the materials furnished, and all the work done, which, in the opinion of the Commissioner of Public Works, shall not be in accordance with these speci- fications, shall be immediately removed and other materials furnished, and work done that will, in the opinion of said Commissioner, be in accordance therewith. Before any materials are placed upon the street or avenue, the Commissioner of Public Works shall approve of the quality and finish of samples of the same, which shall be furnished at his office. 2. Inspectors on Subdivisions of Work. The work under this agree- ment is to be prosecuted at and from as many different points in such part or parts of the street or avenue on the line of the work as the said Commis- sioner may, from time to time, determine, and at each of said points inspec- tors may be placed on the day designated for the commencement of the work thereat. Whenever any work is in progress at or from one or more points at a time, an inspector may be appointed by said Commissioner to supervise each subdivision 'of the same, whether such subdivision be the culling of the bridge-stones, or the excavation for and preparation of the foundation, or the laying of the pavement, or the laying of the bridge-stones or otherwise. The aggregate time of all the inspectors so employed will be the time with which the time allowed for completion of the work under this agreement will be compared. The inspectors will be paid each at the rate of three and one-half dollars per day. *xx, 256. ASPHALT PAVEMENTS. 143 3. Right to Construct Sewers, etc., prior to Laying of Pavement. The right to construct any sewer or sewers, or receiving-basins or culverts, or to build up or adjust any man-holes, or to reset or renew any frames and heads for sewer man-holes, or for Croton water or gas stop-cocks, or to lay gas or water pipes, or to construct necessary appurtenances in connection therewith in said street, or to grant permits for house connec- tions with sewers or with water or gas pipes, at any time prior to the laying of the new pavement over the line of the same, is expressly reserved by said Commissioner ; and said Commissioner of Public Works reserves the right of suspending the work on said pavement on any part of the line of said street or avenue at any time during the construction of the same, for the purposes above stated, without other compensation to the contractor for such suspension than extending the time for completing the work as much as it may, in the opinion of the said Commissioner, have been delayed by such suspension ; and said contractor shall not interfere with, or place any impediment in the way of any person or persons who may be engaged in the construction of such sewer or sewers, or in making connections there- with, or doing other work above specified, or in the construction of any receiving-basins and culverts, or in setting or resetting any curb or gutter- stones on the line of the street or avenue. Contractor to Remove Incumbrances. In case there shall be, at any time stipulated for the commencement of the work, any earth, rubbish, or other incumbrance on the line of the work, the same is to be removed at the expense of the contractor. 4. Bridge-stones. When new bridge-stones are required they are to be furnished in conformity with the following description, to wit : The new bridge-stones to be of blue stone equal in quality to the best North River blue stone, free from seams and imperfections. Each stone to be not less than 4 nor more than 8 feet long, except in cases where espec- ially permitted, and 2 feet wide, and of a uniform thickness, which may vary from 5 to 8 inches, and dressed to a face on top not varying in even- ness by more than one-fourth of an inch, and on the bottom bedded, with sides square and full, and ends cut to such bevel as shall be directed by the Commissioner of Public Works. The new stone to be in quality and work- manship equal to the pattern at the office of the Department of Public Works, and to be cut so as to lay to a joint not exceeding -inch from top to bottom on the ends, and ^-inch on the sides. Old bridge-stones shall be relaid in accordance with the specifications for laying new bridge-stones. 5. Manhole-heads, etc. All the frames and heads for sewer man- holes, and for Croton water or gas stop-cocks, on the line of the work are to be reset or new ones set if required, on a level with the new pavement, by the Department of Public Works or the gas company. The sewer man- holes, if below the grade, will be built up to the proper height by said de- partment. 6. Old Curb and Gutter Stones. The old curbstones along the line of the work, the pavement in the intersections that may be retained, and the pavements adjoining, and also the gutters of the adjoining pavements, as far as may be necessary to obtain proper drainage and adjustment be- tween the old and new pavement, shall be readjusted and brought to the grade and lines of the proposed pavement, as, and to the extent required, without extra charge therefor. 144 ASPHALT PAVEMENTS. 7. The stone-block pavement will be prepared in the following manner for a Foundation. The surface of the stone-block pavement must be thor- oughly swept with stiff brooms until all dirt and fine particles have been removed from the surface, and from the joints to a depth of two inches. The surface must then be brought to a uniform grade and cross-sec- tion, not to exceed a crown of 5 inches on a roadway 30 feet wide, by filling all depressions with a fine bituminous concrete or binder, to be composed of clean broken stone not exceeding i\ inches in their largest dimensions, thoroughly screened, and coal tar residuum, commonly known as No. 4 paving composition. The stone must be heated by passing through revolving heaters, and thoroughly mixed by machinery with the paving composition in the proportion of one gallon of paving composition to one cubic foot of stone. This binder must be hauled to the work and spread with hot iron rakes in all holes or inequalities and depressions below the true grade of the pave- ment, to such thickness that after being thoroughly compacted by tamping and hand-rolling the surface shall have a uniform grade and cross-section, and the thickness of the binder at any point shall be not less than three- fourths of an inch. The upper surface shall be exactly parallel with the surface of the pavement to be laid. Upon this foundation shall be laid the wearing surface, or paving- proper, the basis of which or paving cement, will be pure asphaltum, unmixed with any of the products of coal tar. The wearing surface will be composed of : 1. Refined asphaltum. 2. Heavy petroleum oil. 3. Fine sand, containing not more than one per centum of hydro-sili- cate of alumina. 4. Fine powder of carbonate of lime. The asphaltum shall be specially refined and brought to a uniform stand- ard of purity and gravity, of quality to be approved by the Commissioner of Public Works. The heavy petroleum oil shall be freed from all impurities and brought to a specific gravity of from 18 to 22 Beaume, and fire test of 250 Fahr. From these two hydro-carbons shall be manufactured an asphaltic cement which shall have a fire test of 250 Fahr., and, at a temperature of 60 Fahr., shall have a specific gravity of 1.19, said cement to be composed of 100 parts of pure asphalt, and from 15 to 20 parts of heavy petroleum oil. The asphaltic cement being made in the manner above described, the pavement mixture will be formed of the following materials, and in the proportions stated : Asphaltic cement from 12 to 15 Sand from 83 to 70 Pulverized carbonate of lime from 5,to ijj_ r"o~6 7 544- 184 MISCELLANEOUS ROAD-METALING MATERIAL. PAVEMENTS FROM BLAST-FURNACE SLAG.* In the Hanover district of Germany the blast furnaces make a specialty of a road-metaling material called slag-stone. For its prep- aration the slag as tapped from the furnace is run into a bottomless cast-iron mold, which is tapering to the top and stands on an iron truck. After the slag has cooled enough to have an outer shell suf- ficiently strong to support the melted mass inside the mold is lifted off and placed on another truck ready for use, while the loaded truck is run off to the dump-heap, where the truncated cone is pierced and the slag run on to the ground and covered with cinders and ashes and allowed to cool very slowly. This makes the slag much tougher than when allowed to cool in the open air, and it is said to wear very well when broken properly and placed on roads. The ordinary brittle slag makes a very good foundation for a road, particularly on clay and wet soils, as by rolling, the top pieces form a powder that fills the interstices between the lower fragments so thoroughly that neither clay nor mud can work up through the layer, and on this the more durable wearing layers can be placed. It was found impossible to form any roads on the soft clay surface of the Centennial Fair Grounds at Philadelphia until their beds had been prepared by a layer of well- rolled furnace-slag, after which they stood very heavy teaming without underdraining ; the bonding of the fragments of slag with the thorough filling of the interstices preventing any mud from working through the first or lower layer, thus keeping the road from breaking up. STEEL PAVING BLOCKS. f A substitute for granite blocks for paving purposes is a steel paving block claimed to have superior durability and whose cost is said to be somewhat less than the stone. It is thus described : The block is made of steel strips, some 2^ inches wide by i thick, with a rolled channel on the side exposed to traffic, and con- taining notches about half a foot apart. The weight of these strips is ii pounds to the yard ; they are laid across the street, a distance about 5 inches between centres, and as their length is sufficient only to extend to the middle of the street the proper slope from the centre to the gutters is easily secured. To insure their not slipping side- wise they are bolted together and fastened to wooden sills The support for the new pavement is composed of a firmly constructed bed of gravel, while between the steel strips a compound of pitch and cement is poured, filling the interstices to a level with the tops of the strips, and rendering the surface comparatively smooth. * xvi, 547. fxix, 212. MISCELLANEOUS ROAD-METALING MATERIAL. 185 * Our Milwaukee correspondent sends a newspaper clipping which says : " The North Chicago Rolling Mill Company has com- pleted an order for fifty tons of steel rails, of a peculiar pattern, to be used in paving a block in Chicago. The rails were rolled in the Merchant Mill of the Bay View Works. They are 16 feet 10 inches in length and have a grooved surface on top, to render them rough, so that horses will not slip upon them. The rails will be placed a few inches apart, and the space between will be filled with a patent composition, which is said to be very hard and durable. The pave- ment is to be used where there is very heavy teaming. If the experi- ment proves successful it is probable that many of the Chicago bus- iness streets will be paved in a like manner." EXPERIMENTING WITH A COMPOSITE PAVEMENT IN PARIS.f A correspondent in a letter to Le Genie Civil , calls attention to a composite pavement laid by an American syndicate on the Rue de Rivoli in Paris, which he states in eight days after it was open to traffic began to break up. It seems that this pavement was laid on the Rue de Rivoli, where the traffic amounts to 33,000 vehicles per twenty-four hours, and the contractors who had agreed to keep it in repair for two years failed to take into account this unusual amount of traffic. Hence they are relaying the pavement with greatest care to meet these extreme conditions. Another year's trial will doubt- less demonstrate whether this kind of pavement will be suitable for such heavy traffic. PROPORTIONS FOR CEMENT PAVEMENTS\J The Moniteur de la Ceramique gives the results of some experi- ments by M. Bohme on the durability and resistance to wear of cement pavements. In a series of experiments, with twenty-eight different mixtures of cement with a perfectly uniform sand, he eliminated the variations usually due to irregularities in quality, and second results indicating that the durability of the pavement does not depend materially upon the tensile or crushing strength of the cement as usually determined. In this series of experiments the proportion of sand to cement giving the best results varied from i to i to 2 to i, i^ to i proving best in the majority of cases and being recommended for use with cements whose properties have not been specially investigated. The resistance to wear of pure cement is in general equal to that of a mortar composed of 2 parts cement and 7 parts sand, but this proportion varied considerably, ranging in the experiments from i to 2 to i to 5. *xvi, 685. f xv, 521. Jxviii, 175. l86 MISCELLANEOUS ROAD-METALING MATERIAL. ASHES AND CINDERS.* Professor I. O. Baker, in his address before the Illinois Society of Engineers and Surveyors, mentioned an experimental section of iron pavement in Chicago ; also the experiment in Toledo, of cover- ing unpaved streets with six inches of cinder and ashes. This covering becomes so compact that in winter heavy loads do not cut through it, and in summer it is less dusty than an ordinary earthen roadway. RUBBER PAVEMENT.f For paving streets India-rubber threatens to enter into com- petition with asphalt. A recent number of Kuhlow's gives a fuller account of this new pavement, which was briefly noted in our issue of January 12. It is the invention of Herr Busse, of Linden, who has introduced it in Hanover. He used it first in the summer of 1887 for paving the Gcethe Bridge, which has a surface of about 1,000 square meters, or 10,764 square feet. The new pavement, it is stated, proved so satisfactory that 1,500 square meters (16,146 square feet) of ordinary carriageway in the city were paved with it last summer. The Berlin corporation, being favorably impressed with the new pavement, has had a large area paved with India- rubber as an experiment, and the magistracy of Hamburg is like- wise trying the pavement. It is asserted that the new pavement combines the elasticity of India-rubber with the resistance of granite. It is said to be perfectly noiseless, and unaffected either by heat or cold. It is no^ so slippery as asphalt, and is more durable than the latter. As a covering for bridges, it ought to prove excellent, as it reduces vibration ; but a question may be asked as to its cost. The expense must be heavier than that of any known pavement. xv, 658-! xix, 157. CHAPTER V. CURBS, SIDEWALKS AND TRAMWAYS. A NOVEL FORM OF STREET CURB.* As a matter of interest we reproduce from La Semaine des Con- structeurs of September 18, a description of a novel form of street curb, recently introduced at Verdun in France. This application of cast iron is the invention of Mr. Nicot, a contractor for~asphalt paving, and it is now in use on about two miles of sidewalks. The curb is cast in lengths, as shown in Fig. 2, of an L-shaped "section, " ' ^* 'I'U''' with ribs or knees, the bearing of the latter being enlarged by an expansion of the bottom flange. The segments rest on a bed of concrete, and the concrete is also filled in upon the bottom flange, as shown in the sections, so that the curb is held firmly in place. The surface of the sidewalk is finished in asphalt to the level of the top of the curb. *xv, 658. i88 CURBS, SIDEWALKS AND TRAMWAYS. In addition, a peg of wood or iron (Fig. i) is driven in the earth behind, opposite the end ribs, and secured to the ribs by a galvanized iron wire. This serves to keep the curb to place while the process of filling is progressing. The reviewer criticises this as smacking too much of the gardener. The suggestion is made that a " fish-tail " rod screwed into an enlargement of the ribs at the joints in;the curb, and buried in a small mass of concrete, as shown in Fig. 3, would be more in accordance with sound ideas of con- struction. FIG. 3. The reviewer considers the curb as one well worthy of investi- gation and trial, and we would add that with such improvements as experience may suggest it may be worthy of introduction in locali- ties where good stone for curbs is not obtainable. AN ARTIFICIAL STONE FOR STREET CURBS, ETC., USED AT GALES- BURG, ILL.* From an engineer traveling in the West we learn that in some of the Western States no stone can be obtained near by suitable for street curbs, rendering it often necessary to transport material a long distance for this purpose, or pave the street without curbs. When recently in Galesburg, III., he noticed a method there in use which may be of interest to some of our readers, and which he thus describes : Ohio stone is used to some extent for curbing, but has a rough appear- ance. The best material used is known as Asbestine Building Stone, and is prepared of German Portland cement, sand and broken stone. The dimensions of each piece of this curb are uniform, having a length of 4 feet, and in section 6 inches at bottom and 5-^ inches at top, with the two upper edges rounded. The ends are fitted to make a close joint, with mortise and tenon molded in the material. The material forming this curb is rammed into wooden molds, the molds being made in sections, permitting them to be easily removed when the material has set ; the usual time allowed for this purpose is nine days, the curb being fit for use in a few days after. *xx, 231. CURBS, SIDEWALKS AND TRAMWAYS. 189 The inner face of the mold is varnished to prevent the material from adhering to the wood. No broken stone is visible on either face of this curb, it therefore has the appearance, when set, of fine axed natural stone. Narrow strips of wood, one inch in thickness, are laid on the bottom of the trench on which the curbing is set to keep the grade line uniform ; wood is used for this purpose as there is no suitable stone in the neighbor- hood. This curb is furnished and set for fifty cents per lineal foot. It is manufactured by W. H. Walburn, of Galesburg, 111. SIDEWALKS. FOOTPATHS IN ENGLAND.* We interrupt our description of the pavements of Liverpool to notice a paper entitled " Footpaths " (sidewalks), by H. Percy Boulnois, M. Inst. C. E., Borough Engineer of Portsmouth, which is of interest in connection with this series. Government Requirements. The paper first remarks on the pro- portion between the widths of footways and carriageways adopted by the Local Government Board. The requirement is that every new street shall have a carriageway at least twenty-four feet wide, with a footpath each side " of a width not less than one-sixth of the width of such street," (meaning, as is explained, one-sixth of the width of the carriageway). The width of roadway should be, if possible, some multiple of eight feet, " since this is the allowance of vehicles passing each other at a rapid rate." The gutters at each side to be not less than three inches deep, or more than seven inches. Curbs to be set on " clean sharp bal- last," and well rammed. Materials. The materials used for footpaths may be classified as: (i) Natural stones; (2) Natural asphalts; (3) Artificial asphalts and concretes ; (4) Brick ; (5) Gravel and stone chippings. Requirements. The requirements of a good covering for side- walk are that it shall not be slippery and shall not scale or flake. It must be durable, not easily abraded, strong, of uniform quality, dry rapidly after rain, and dust should not readily adhere to it. Its absorbent powers should be tested. Its quality will also be in a measure indicated by its microscopic appearance and specific gravity. Its wearing qualities may be tested by rubbing and drilling, but better by actual test under a known traffic. Natural Stones. Of natural stones granite is durable, but wears very slippery, is difficult to work, and is expensive. Yorkshire flags are much more largely used. They are readily cut, do not wear smooth, and are never slippery from wear. They IpO CURBS, SIDEWALKS AND TRAMWAYS. are more liable to breakage, absorb considerable moisture, and tend to laminate when exposed to frost. (The same is true of many of our American flagstones.) The wear under heavy traffic in the city of London was about one-sixteenth of an inch per year, and this is given as the rate in the Strand for every 9,000,000 foot-passengers. Slate wears very slippery ; most of the freestones are too soft ; and some of the limestones are very brittle and very slippery. Natural Asphalts. Of natural asphalts, that is recommended which contains about 7 per cent, of bitumen, and, where possible, that it should not be laid except by the compressed method. The "mastic " (which contains more bitumen) is considered only "suita- ble for broad paths with light traffic." The former should not be laid of less than i -inch thickness, and the latter of |-inch; it being essen- tial that a foundation of cement concrete three inches thick be first provided, " as asphalt is like a mineral leather or elastic skin, and has no strength in itself, but acts solely as a cover to the concrete," which actually carries the traffic. u It is almost impervious to moisture, and is the best pavement that can be used from a sanitary point of view." In Birmingham it requires relaying every five or six years, and compressed asphalt paths have lasted ten years in some of the busiest thoroughfares in London. In Leicester, mastic paths (uncompressed) have lasted fifteen years. Under considerable traffic it is estimated by the author that compressed asphalt one inch thick will last twelve years. Artificial Asphalts and Concretes. Of artificial pitch mastics the composition of one of the first used is given as 50 parts waste products of tar-oil, 20 of caustic lime, 200 of pitch, 30 of sawdust^ and 700 of iron slag, grit, or chalk ; the materials being simply mixed, spread in layers, and rolled. Another laid in 1840 was Stockholm tar three parts, chalk two parts, and sand one part, boiled together and spread hot. One of the best modern mixtures is of gravel or stone chippings screened to the several sizes, passing through sieves of i^-inch> f-inch, I -inch, and J-inch mesh, and heated on iron plates ; when dried and thoroughly heated, the following mixture was made and well-boiled : 12 gallons of tar, 56 pounds of pitch, and two gallons of creosote, this quantity, while still hot, being added to about a ton of the hot screened materials. A thin layer of the largest material is laid first and rolled by a -ton roller, and the others similarly in succession, the finest on top. The chippings make the best pave- ment. The foundation must be dry, and the pavement is best laid *' in the spring or winter, if dry, as a hot sun draws the composition away from the stone on to the surface of the path." The surface should be dusted over with fine grit or stone- dust, " and this facing, CURBS, SIDEWALKS AND TRAMWAYS. 19 1 accompanied by a thin ' painting ' with tar, should be repeated at least every other year." The life of these pavements is given variously at from five to twenty years. The disadvantages named are its dark color, its wear- ing gritty and bumpy, and its "rather difficult repair." In very hot weather it becomes sticky or soft. " Tar pavement must only be reckoned as a substitute for ordinary graveled footpaths. It must not be compared with paved or asphalted paths." It is largely used for suburban footpaths. Monolithic pavements of Portland cement concrete are gaining in favor, " and may be looked upon as the pavement of the future," and these when properly laid, with joints at about six feet intervals, are found to be very durable. Shingle or gravel does not work so well as crushed granite, since the former is apt to become dislodged or else protrude and make a rough surface. A bottom layer, 2 1 inches thick, of one part Portland cement to six parts shingle or stone, with a |-inch layer on top of one part cement to two parts finely broken and well-washed granite, are recommended. Great cleanliness and care in mixing are needed, with thorough ramming of the concrete and troweling of the surface. Traffic should be kept off until it is thoroughly set by a covering with boards for a fort- night, and afterward by a covering of wet sand. This description of pavement is rather slippery and should have a light cross-fall. It may be molded in blocks and laid in this form if desirable. After the upper surface is worn these can be turned and will present a fresh wearing-surface. Brick. Brick pavements are undesirable on account of the multiplicity of joints and their consequent insanitary character, their harshness to the foot, and the necessity for a concrete foundation to keep them level. Special vitrified bricks have a life under heavy traffic of thirty years and upward. Gravel and similar materials are only desirable for cheapness. In conclusion the author states that "asphalt has suffered ' in repute because inferior materials have been used under that name. Tar pavement is an excellent substitute for gravel paths, and is a good pavement for light traffic. Concrete, monolithic, and flagged pavements are every day gaining in favor and have much to recom- mend them." Comments on Mr. Boulnois* Paper. We wish to remark, by way of comment on the proportion between width of roadway and side- walk given in the paper, that, while it might be an advisable one in streets almost entirely devoted to wheel traffic, it should not be adopted in other localities. In towns of moderate dimensions where are planted the most pleasing results will be obtained IQ2 CURBS, SIDEWALKS AND TRAMWAYS. with the walks nearly or quite one-half the width of the roadway, and even in busy streets it will be found that about one-third, exclusive of stoops or other projections, is not too great a width for the sidewalks. With the necessity in this latitude for providing for heavy snows the depth of gutter mentioned is too small. The general rule holds good that the better the surface of a roadway the less crown is required to carry water to the gutters. The experience of the pres- ent writer on streets with a graveled surface where the longitudinal fall obtainable was from o.i of a foot to 0.2 of a foot per 100 feet was that a crown of 18 inches on a roadway 40 feet wide, reducing to i foot on one 20 feet wide, on newly made streets, was not objection- able in use and became rapidly less from wear. On the contrary, crowns of about 6 inches are quite sufficient on well-paved streets which are kept clean and in good surface. It is a very common fault to give too steep a cross-slope to flag and other footpaths. The sole object of this slope is to carry water to the gutter. Since the surface is required by municipal ordinances to be kept clean from snow, there is sure to be at times a thin coat- ing of ice formed upon it, and under such circumstances a cross- slope of |-inch per foot becomes dangerous to passengers. It will be found in practice that J-inch per foot will give the most satisfac- tory results. In comparing practice in our cities with that abroad it should be borne in mind that much greater care is usually exer- cised there to obtain accuracy of alignment and smoothness and per- fection of surface ; also, that much greater attention is paid to keep- ing the surface in repair. We may well take a lesson from them in this important matter. ASPHALT AND CONCRETE FOOT PAVEMENTS.* The object of this paper is to draw the criticism of the members of the association upon the experiments and experience of the writer and others, on asphalt and concrete as materials for foot-pavements, and, if possible, to induce others to carry forward experiments with a view to perfecting the use of these pavements. The writer desires to place in the forefront of the paper the fact that the credit of the Hornsey experiments herein referred to is due to Mr. T. de Courcey Meade, A. M. I. C. E., who most readily placed them at the disposal of the writer for this paper; and also his obligations to the French Asphalt Company, the Val de Travers Asphalt Company, the Imperial Stone Company, and others, for the *A paper by George R. Strachan, A. M. Inst. C. E., of Chelsea, Lon- don, S. W., read at the annual meeting of the Association of Municipal and Sanitary Engineers at Leicester, July, 1887. xvi, 266. CURBS, SIDEWALKS AND TRAMWAYS. 193 information given. Every pavement described has been personally examined by the writer, and the exact locality of each is stated, so that any one may examine them for his own information. Asphalt, its Nature and Occurrence. Asphalt, properly so called, is a natural compound of carbonate of lime and bitumen, and is found principally in volcanic areas. Men of erudition have asserted that it was the "pitch" used to make the Ark watertight, and that it was the "slime" used as a mortar in the construction of the Tower of Babel and the city of Babylon. If such ancient uses of this sub- stance are facts, its virtues were strangely lost sight of in the inter- vening centuries, for it is not till 1700, A. D., that its use became common. It was then used for the purpose of extracting " balm " from its beds, which was used for medical purposes and was credited with superior healing powers. The origin of the asphalt beds has given rise to much speculation. A Swiss geologist has made an effort to explain their formation in a striking manner. Starting from the observation that all organic matter exudes bitumen in decom- posing, he suggests that the beds are the remains of huge banks of oysters, the shells of which furnished the carbonate of lime, and the oysters themselves furnished the bitumen. As the asphalt beds are in some cases 27 feet thick, and their areas are measured by square miles, it is evident that oysters were plentiful in those days. The works of the French Asphalt Company are described, as that company has executed all the asphalt works in Chelsea; but the writer wishes to say that the Val de Travers Company, Claridge's Asphalt Company, and others, do equally good work. The mines of the French Asphalt Company, from which their English supply of asphalt is obtained, are situated at St. Ambroix, in the south of France. The asphalt is in seams, which lie nearly hori- zontal, and which have their faults, bends, etc., like coal seams. The bed and roof of the seams are of pure carbonate of lime rock, pre- sumably the same as that of which the asphalt is largely composed. The seams vary from three to five feet in thickness, and are worked by drifts from the outcrop on the hillside. The rock is mined by blasting and hand labor, and comes from the drifts in pieces meas- uring one cubic foot and downwards. The asphalt then has a very dark chocolate color, and appears to be a tough homogeneous sub- stance, with striations of white matter running through it parallel to its natural bed, which are probably narrow seams of carbonate of ]ime. When it is exposed to a hot sun the surface will glisten with small fatty beads of bitumen, but at ordinary temperatures it is dry. After exposure to the air the surface turns a dull white color, owing to the evaporation of the bitumen; but this Change is only skin deep. The rock is conveyed to Marseilles just as it leaves the mine, and is i 9 4 CURBS, SIDEWALKS AND TRAMWAYS. shipped to England. Formerly the beds of asphalt yielded a supply of natural bitumen, but twenty years ago the supply ceased, owing- it is believed, to some widespread cause, as several mines were affected in the same way at that time. Preparation. At the depot of the company at Stratford, the rock as delivered by ship is passed through a crusher which acts like a Blake's crusher, save that the solid jaw is replaced by a series of knives, and by which it is reduced to pieces not exceeding three inches in length. The pieces are poured into a Carr's disintegrator, which has spindles revolving 800 times a minute in opposite direc- tions, and which reduces the asphalt to powder. The powder is screened through a rotatory cylindrical sieve (144 to the square inch) and is then stored in sacks. The asphalt varies in the proportion of bitumen it contains. The richer parts are ground and stored separately from the other, and are afterwards mixed in suitable pro- portions for the particular use to which they are to be applkd. Composition. The following are analyses of asphalt rock of average richness at this stage : No. i Sample. No. 2 Sample. Average. Bitumen I 70 10.60 IO 65 Carbonate of lime 88.05 88.15 88.10 Silica o 55 o 4.0 o 4.8 Alumina O IO 015 O 12 Peroxide of iron . . O.2O O IO o 15 Moisture O.4O o 60 o. 50 IOO.OO IOO.OO 100.00 Making the Foothpath. When the asphalt is about to be used, the powder is poured into revolving roasters, and roasted for three hours at a temperature of 280 Fahr., during which operation the moisture is driven off. As the asphalt chars at 320 Fahr., care has to be exercised as to the proper temperature. It is loaded direct from the roasters into carts lined with sheet-iron, covered with hemp cloths, and thus protected it retains its heat till it is taken to the site where it has to be laid. It is carried from the carts in baskets, spread over the foundation by means of a rake and rammed solid by a series of blows from heavy heated rammers. The surface is ironed by a heated iron, which draws bitumen to the top, and in a few hours it is ready for traffic. This form of asphalt is known as compressed asphalt, and is the form always used for carriageways and frequently for footways. Mastic Asphalt. The other form of asphalt is known as mastic asphalt, and is a manufactured compound made up of natural as- CURBS, SIDEWALKS AND TRAMWAYS. IQ5 phalt, artificial bitumen, and grit. The asphalt is reduced to a powder as described. The artificial bitumen is used because of the scanty supply of natural bitumen. Its principal component is Trini- dad pitch, to which is added from five to seven per cent, of shale oil. The mixture is boiled for twenty-four hours; the top liquid is ladled out, and is the artificial bitumen. It is a soft, viscous, black substance which softens under the sun's rays. Its quality is tested by taking a piece between the fingers and drawing it out to a string; if it does not snap until drawn out very fine it is of good quality. The grit is obtained from B ridgeport, is wholly composed of flint, very clean, and the pieces do not exceed -J-inch in size. Its Preparation and Use. The mastic asphalt is prepared as follows : From 5 to 7 per cent, of artificial bitumen, from 20 to 30 per cent, of grit, and the balance in powdered asphalt are placed in a covered caldron and heated for four or five hours. The mixture liquefies at 280 Fahr. to 300 Fahr. If it is to be used near the works (within ten miles), it is run into locomobiles (boilers on wheels), with a fire under them, and drawn to the site. When it is used, it should be hot enough to vaporize a drop of water. It is carried in pails and spread over the foundation by means of. a float^ Silver sand is then spread sparingly over the surface and rubbed in by floats. In six hours the footway is ready for traffic. One ton of asphalt covers 20 square yards when laid one inch thick. When mastic asphalt is to be laid at a distance from the works instead of running it from the caldrons into the locomobiles it is run into molds, and molded into flat cylindrical pieces weighing about 56 pounds each. These are taken to the site, placed in a caldron, from 3 to 4 per cent, of additional bitumen added to make up for the loss by evaporation, and heat applied to reduce it to a liquid con- dition. The laying is then performed in the same manner as before described. This description may be taken as applicable to the method adopted by the Val de Travers Company, with a few variations in the proportions used. Analyses of Rock Asphalts. The following analyses of asphalts are of interest, as they are those of rocks of average richness- Val de Travers Co. French Asphalt Co. Bitumen . . .... 9.75 10.65 Carbonate of lime etc 80.75 88.85 Moisture . 5O . 50 100.00 100.00 196 CURBS, SIDEWALKS AND TRAMWAYS. The following analyses, in a different form, were placed at the writer's disposal by Mr. Mead.e. VAL DE TRAVERS. FRENCH ASPHALT Co. M 8 ti S o g-tf g' s From Hornsey Lane. SS-d O O Cfi &lx 0.4 6.0 16.9 76.7 n4 o o M Silica 0.6 5.8 13.0 80.6 o.5 5-8 9-8 83.9 0.3 6.5 13.6 79.6 0-4 8.2 16.8 74.6 Volatile organic matters (tar, oils, etc.). . . N on- volatile organic matters Lime, etc 100. IOO.O IOO.O IOO.O IOO.O This detailed description and the numerous analyses of good asphalts have been given, so that spurious asphalts may be avoided. Traffic Durability. In Chelsea there are i6 miles of foot- ways paved with mastic asphalt, having an area of 68,290 square yards. On the Queen's Park Estate there are 41,500 square yards, which have been laid five years, and which are now in good con- dition, not having cost one penny for repairs. In King's Road, at Walpole Street, a length has been laid for seven years. The foot traffic over it is 7,500 persons in eighteen hours. At the end of the first five years it was cut open, and the wear was found to be such as had reduced the thickness to a spare -J of an inch, the original thickness being i inch full. On the east side of New Bond Street a length of mastic asphalt was laid thirteen years ago between Ox- ford Street and Conduit Street, the thickness being f of an inch. The asphalt is now wearing through on to the concrete in the line of traffic at the forecourt line. The cost for repairs has been so trifling that it may be neglected. In this case the concrete foundation is as sound as before, and all that is necessary to restore the footway is to relay the asphalt at about two-thirds of the original cost, when the pavement will be good for another thirteen years. As the traffic here is very severe and the footway narrow, it is reliable evidence of the durability of asphalt. Foundation. The foundation of the asphalt footway is made with 3 inches of Portland cement concrete (6 to i) of very good quality. The surface is smoothed with the shovel, and four days are allowed for drying. The concrete has been laid hitherto without any joints. The mastic asphalt is floated over the surface, and the path is then completed. Mastic asphalt does not show any cracks on the surface. The concrete foundation, when the asphalt is re- CURBS, SIDEWALKS AND TRAMWAYS. 197 moved, shows the regular tree-like cracks all along its length, branching from the kerb to the back line, but the elasticity of the mastic asphalt is sufficient to resist the tearing action of the concrete as it contracts. Expansion and Contraction of Concrete. A study of the asphalt question resolves itself principally into a study of the movements of concrete when laid in long lengths, narrow widths, and small thick- nesses. The writer inclines to the opinion that concrete has in itself a small power of contraction, apart from any considerations of tem- perature. The experiments of Dyckerhoff, which show that neat cement (slow-setting) had an average expansive power over twelve months of .0734 per cent, and quick-setting cements of .2019 per cent., and that concrete (3 to i, sand) had an expansive power of .0264 per cent, (slow-setting) and .0320 per cent, (quick-setting), seem to show the contrary to be the case. The writer laid down a length of con- crete (6 to i, ballast), 52 feet long, 12 inches wide and 3 inches thick, under a shed which had an open front, but so that the sun did not touch the concrete. The strip was laid on sand so as to give it freedom of movement. Another strip 26 feet long, of the same width and thickness (3 to i, pebbles), and a third of the same dimen- sions (3 to i, sand), were also laid under the same conditions. The only movement discernible, at the end of one month, was a slight contraction in length in all the samples. The uniform experience of concretes under asphalt is that cracks occur, which would tend to show that contraction and not expansion is the rule. At the same time, the writer has experience that concretes do expand, but this he attributes to the action of temperature. It is no uncommon thing to see the surface of an asphalt path raised crosswise in an irregular line, as though a small tree root was under it. In every case where the asphalt has been uncovered at these points by the writer, he has found the concrete crushed and the concrete on the falling level thrusting itself under the concrete on the rising level. This effect is most marked on hot days. In January last the writer laid some thousands of feet of asphalt path in St. Luke's Gardens, Chelsea. The sun is on it all day, and during the hot weather at the beginning of June, the number and size of these raised lines was astonishing. Shortly after midday they were most pronounced, and towards night they were less prominent. As a further evidence of the expansion of concrete under the sun's rays the streets in the city can be named. The footway and carriageway are in asphalt on concrete. The ex- pansion of the concrete in the carriageway presses the kerb at the bottom ; the expansion of the concrete in the footway presses the kerb at the top on the opposite side, and the two have tilted up the kerb in a marked manner. The writer has on a hot day taken up 198 CURBS, SIDEWALKS AND TRAMWAYS. asphalt on a footway and has found the heat much greater under the asphalt than on the surface. In order to avoid the expansion show- ing itself in footways the concrete should be laid in sections, and the joints between them filled with some compressible substance. Compressed Asphalt. Cracks. Compressed asphalt has about one-third longer life than mastic asphalt under the same conditions. The cost is the same, but the use of compressed asphalt for this pur- pose has not been universally followed by reason of the cracks that appear on its surface. The cracks do not tend to spread under traffic, nor does the asphalt wear more at these parts than at others. They are unsightly, however. It is found that these cracks are ex- actly of the shape and in the position of the cracks in the concrete foundation. Compressed asphalt has no elasticity in itself, and when subjected to the contracting force of the concrete it is torn through. It is an admirable tell-tale of the movements of the con- crete. Much ingenuity has been displayed in endeavors to avoid the cracks. The first step was to localize them. This was done by laying the concrete in i2-feet bays and in alternate bays, and filling up the screed space with fine concrete. The contraction then showed its effects at these places, with a result that a series of regu- lar straight cracks appeared instead of the irregular tree-like cracks when the concrete was laid in one piece. These effects can be seen at many places in London without specifying any particular place. Having localized the cracks, an experiment was made at Hornsey to avoid them. A strip of bituminous felt six inches in width and 24 -inch thick was placed on the concrete over the whole length of the screed mark. This felt has much elasticity, and the object of the experiment was to ascertain whether it would take up the con- tracting movement of the concrete and absorb it. The length is laid at Crouch Hall Road, between Coolhurst Road and Clifton Road. The result has been that instead of one crack at each screed mark there are two, one on each side of the narrow strip of felt. It is evident that the concrete in contracting compresses the asphalt longitudinally, and that the cracks appear at the points where the op- posing motions meet ; and as the strip of felt represented a narrow area which was free from these forces a crack appeared on each side where the forces took effect. In Archway Road, Hornsey, another experiment was made by covering the screed mark with a strip of mastic asphalt nine inches in width and J-inch thick, just as in the last case with felt. For three months no cracks appeared ; then a few slowly and at irregular intervals showed themselves ; but during the severe winter of 1886-7 every screed mark showed its crack. These cracks were irregular in line, but they are confined in each case to the area covered by CURBS, SIDEWALKS AND TRAMWAYS. 199 the mastic asphalt. These footways are laid on a 3-inch foundation of concrete. In Marlborough Road, Chelsea, an experiment was made on different lines. A foundation of concrete six inches thick was laid, and the compressed asphalt laid on it. For four months no cracks appeared, but after that time they occurred at frequent intervals, though they are fewer than usually appear on a 3-inch foundation. When the asphalt and concrete were removed at the cracks it was found that the crack extended through the whole thickness of the concrete. This experiment was based on the observation that cracks do not appear in compressed asphalt car- riageways, and as the principal difference between the foundations in the footways and carriageways is the thickness of the concrete, it was assumed that it was the cause. The observation is, however, an incomplete one. In streets of light traffic the cracks do appear in the asphalt, as in Little Blenheim Street, Chelsea, and elsewhere. In streets of heavy traffic the cracks in the concrete tear the asphalt as they slowly form, but the traffic welds the asphalt together again before they show on the surface. In footways of heavy traffic there are fewer cracks than in those of light traffic, for a similar reason. At Muswell Hill, Hornsey, the experiment of covering the whole area of the footway between Onslow Rise and Grosvenor Gardens with bituminous felt was tried. The felt was in 3-feet widths, and was laid longitudinally with butt joints. At the circular kerb the pieces were necessarily somewhat patched. The result has been that cracks have appeared at every joint of the felt with mar- velous fidelity, owing to the movement of the concrete. In White- head's Grove, Chelsea, between Marlborough Road and Keppel Street, on the north side, a length was laid in 1885 on a 3-inch con- crete foundation, which was covered with mastic asphalt J-inch in thickness. On this J-inch of compressed asphalt is laid. The mastic asphalt was laid to absorb by its elasticity the movement of the concrete without transmitting it to the compressed asphalt. It has survived two winters of great severity, and has lived twenty-one months without any cracks appearing. From this it would appear that the principle of a material between the concrete and the com- pressed asphalt which will absorb the effects of the movements of the concrete is a correct one, and the writer invites the members of the association to experiment on cheapening the method. The present result is an increase of life of 33 per cent, at an increase of cost of 12 per cent. Durability. As evidence of the durability of compressed asphalt in footways, those in Cheapside may be mentioned. They were laid in 1876 at a thickness of i inch, and are now wearing through. On the south side of the Strand east of Wellington 20O CURBS, SIDEWALKS AND TRAMWAYS. Street i inch of compressed asphalt was laid in 1881, and has had only the most trifling repairs. The streets in the city with the heaviest foot traffics in the world are paved with compressed asphalt on the footways. Advantages of Asphalt. The advantages of asphalt foot pave- ments are durability, a smooth surface unbroken with joints, a good foot-hold, even and regular wear, their impervious character, and the readiness and neatness with which they are repaired. They have a sombre appearance, and show water on their surface longer than stone pavements. They wear to the last thickness without breaking up, and give a useful wear for the whole of their thickness. When a stone or other pavement has worn i inch it may not be half worn through, but its usual life is over. Where there are cellars under footways, asphalt as a material for footways is unrivaled. In ordinary traffics, such as those named in King's Road (7,000 to 8,000 persons per day), an asphalt pavement can be laid i inch thick with the certainty that for at least ten years it will need no repairs whatever. This pavement has also the advantage that the foundation is always preserved and good for use again when the wearing surface of asphalt has to be renewed. Cost. The following abstract of the present contract schedule in Chelsea will give the prices for these pavements. Per sq. yd. * d. Compressed or mastic asphalt i inch in thickness on 3 inches of concrete o 6 3 Ditto, ditto, f inch thick o 5 6 Compressed asphalt f inch thick on \ inch of mastic asphalt, laid on 3 inches of concrete o 7 o Compressed or mastic asphalt i inch thick on existing concrete foundation (relay) o 3 6 Ditto, ditto, f inch thick o 3 o These prices carry a guarantee of free maintenance for ten years. The Vestry prepares the foundation for the concrete in new work at a cost of 2d. per square yard. The specification provides that the asphalt will be cut open at distances not exceeding 50 feet apart, and the thickness measured. Five out of every six of these measurements must be at least the specified thickness, and the average of every six must be at least the specified thickness. The specification is strictly adhered to. The cost of the foot pavement in New Bond Street, already referred to, over twenty-six years* would be as follows at per square yard : s. d. Preparing foundation o o 2 Laying concrete foundation and f inch mastic asphalt. ... o 5 6 At end of 13 years relaying mastic asphalt (life 13 years). 030 Repairs o o o Total.. ,088 CURBS, SIDEWALKS AND TRAMWAYS. 2OI or a cost per year, not including interest, of qd. per square yard. It should be mentioned that the small cost of renewing asphalt foot- ways is due to the fact that the asphalt taken up is as good as new asphalt after it has been cleared and prepared, and is re-used for footways. Concrete Footpaths In dealing with the question of concrete as a material for foot pavements, the writer cannot claim such an experience of it as he has had with asphalt. In 1880, however, the Vestry of Chelsea had laid by the respective makers a series of pavements in King's Road against the Royal Military Asylum wall, and in 1885 a report was made on them by the writer. So many applications for copies have been made that it is now out of print, and as applications continue to be made, the results of the experi- ments are herein set forth for the information of the Association. Construction. The writer holds that a knowledge of the manu- facture of these pavements is useful information, and therefore he incorporates a description of the manufacture of imperial stone pavements. The depot of the company is at East Greenwich, on the banks of the Thames. The aggregate used by the company is broken granite. Flint has been used, but the pavement in wear became very slippery. Kentish rag has also been used, but its wear was too rapid. The granite is broken, so that it passes a ^ sieve. After screening it is carefully washed, as the dust acts as a coat round the piece, and prevents the cement laying hold of the granite. The washing machine is a slanting archimedean screw, working in a trough, with openings in the thread of the worm. The water is run in at the high end, and the screened granite pieces put in at the lower. The screw churns the pieces over and over each other, and carries them up by its motion. The clean water meets the cleanest granite, and thus the pieces are not soiled by the dirty water they make. About 8 per cent, by weight is washed out as waste. The importance of a clean aggregate is seen when it is stated that briquettes made from washed pieces have a tensile strain of 15 to 20 per cent, higher than those made from unwashed pieces, when tested under similar conditions. The cement used is the best Portland, and is required to stand a tensile strain of 350 pounds per square inch after seven days' immersion in water. As a matter of fact, the cement used runs to an average of 425 pounds on the square inch. Hitherto a residue not exceeding 10 per cent, on a 5o-mesh was allowed, but the value of increased fineness is recog- nized, and preparations are being made for a cement that will not leave a residue of 10 per cent, on a 76-mesh. The weight runs from 116 to 120 pounds per striked bushel Before use, the cement is laid out to cool for fourteen days, and is turned frequently in that 202 CURBS, SIDEWALKS AND TRAMWAYS. time. Great care is taken to keep the direct rays of the sun off the cement. The company exposed part of a sample of cement to the sun, and exposed the other part to the air. It was found that the part exposed to the sun showed loss of strength equal to 50 per cent. The soluble silica used for the induration of the stone is a clear viscous substance made from pure flint and caustic soda, which are digested by heat under pressure in Papin's digester or an analogous machine. Its strength is technically known as 140 Twaddle, which shows 1,700 on a hydrometer. The silica is diluted with water until it shows 1,250 or 1,300 on the hydrometer, and is then a clear copper-colored liquid. The stone ,is made of three parts by measure of washed granite and one part of cement. They are thoroughly incorporated in a dry state in a horizontal cylinder by machinery, and when this is secured, water is sparingly added, and the mixing continued. At each mix- ing there is made sufficient concrete for a 3'x2'x2" slab only. When it is ready for putting in the mold, the concrete does not appear to the eye to be sufficiently wet. The molds are metal-lined, true in shape, with clearly defined arrises. Before the concrete is placed into them they are oiled all over, and then placed on a trembler. This is a machine which gives a rapid vertical jolting motion to the mold. When the machine is started, the concrete is placed into the mold by small shovelfuls at a time, and two men with trowels spread it over the mold. When the mold is filled they pat the concrete with the trowels, the water rises to the surface and an even smooth face is secured. The mold and concrete are then removed to a rest for two days. The whole operation of mixing the concrete and making the slab in the mold is completed in six minutes. Machine-made stones are of necessity homogeneous, as veneering is impossible dur- ing the process. The slabs when taken from the molds at the end of the two days are air-dried for seven or nine days, and then immersed in a silica bath for seven or nine days more. They are then stacked in the open for some months before use. The value of the silica bath is in hastening the hardening of the stone. At the end of a month the stone will stand from 30 to 40 per cent, more tensile strain if silicated than if air-dried only. It is doubted by Mr. Faija whether silicating increases the ultimate strength of con- crete. The stone so prepared stands a tensile strain of 650 Ibs. on the square inch when three months old. Strains of 1,000 Ibs. have been obtained, but they are not the average. The value and excellence of this concrete is shown by the fact that though the neat cement has 75 per cent, of aggregate added to it, yet in three months the mixture bears nearly double the tensile strain of the neat cement CURBS, SIDEWALKS AND TRAMWAYS. 203 after seven days. The writer was shown the original of a report by Kirkaldy, dated September 6, 1882, in which one sample of stone took 8,075 I DS - per square inch to crush it, and another reached the marvelous strength of requiring 9,492 Ibs. per square inch to crush it. Comparison of Different Pavements. In the King's Road exper- imental pavements the makers laid their pavements with the knowl- edge that they were competing with their rivals. They were laid in 1880. Asphalt, York stone, Ferrumite stone, Victoria stone, and Imperial stone were laid side by side and subjected to the same traf- fics. The writer includes the York stone results, though not strictly coming within the subject of the paper. In June, 1884, the Ferrumite stone was removed, as its slipperi- ness had become a source of danger. Its area was taken by Wilkin- son's granite concrete pavement and by Shap-stone pavement. After five years' wear of the original stones, the following results were obtained : The York stone occupied an area of 87 square yards ; the orig- inal thickness was 3 inches ; the number of stones 123, of which, after five years' wear, 10 had broken edges, 16 had broken corners, 21 had their surfaces peeling off, and 6 were worn so as to be dan- gerous. The wear was not measurable by reason of the uneven thickness of the stones, but it was unmistakable. The foot-hold was good in all weathers. The actual cost was Ss. id. per square yard laid. The Victoria stone occupied an area of 8i square yards ; the original thickness was 2 inches ; the number of stones 168, of which 35 had broken edges and corners, 2 had their surfaces peeling off, and 3 were visibly cracked across. The wear was not quite -inch at the greatest traffic line. The joints of the stone were pleasing, and the color cheerful. The foot-hold is not so sure as that of York stone in dry weather, and in a drizzling rain it approaches shpperi- ness. The cost was 6^. $d. per square yard laid. The Imperial stone occupied an area of 90^ square yards ; the original thickness was a full 2\ inches ; the number of stones 187, of which 1 8 had their corners and edges broken, and i had its sur- face partly peeled off. The wear was not quite ^-inch at the great- est traffic line. The regularity of the joints is pleasing to the eye, and the color is light and cheerful. The foot-hold is more sure than that of the Victoria stone sample, but it becomes somewhat slippery in drizzling rain. The cost was 6s. per square yard laid. The experience gained with the Shap-stone laid in 1884 is more limited, but the stone does not appear to be better than the concrete stones described. The length laid in situ by Messrs. Wilkinson is 204 CURBS, SIDEWALKS AND TRAMWAYS. subject to the same remark, but the aggregate is already wearing up. It is laid in 8-feet bays. A repair made in it is a great dissight to it. The effect of the traffic in wear is visible. Mr. Walker, of Leeds, has laid down (1886) in King's Road a short length, in bays about 4 feet square. It has a very smooth sur- face, and appears to be a very good pavement. He lays a founda- tion of ballast concrete 2\ inches thick to within |-inch of the fin- ished surface, and cuts roughly through it so as to form the bays. He then floats the surface with fine rich concrete, made of one part of cement to one or one and a quarter parts of crushed granite or slag which pass through a -^ sieve. This is then cut through with a knife into bays of small areas. The foot-hold is fairly secure and the wear very satisfactory. No cracks appear when the bays are made less than 10 feet square. At 322 Oxford Street a piece has been down three years, and no wear is visible. He claims that his fine rich concrete on the surface attains more nearly to the texture of York stone than any other pavement. The joints, however, have a tendency to spread. Concrete pavements laid in slabs have two serious disadvan- tages. The writer's experience refers to Victoria stone, but there is no reason to suppose that slabs of other make are free from them. The first is the annoyance caused by the hard metallic sound of the footfall on them, which is especially noticeable at night. The other is their brittle nature and the presence of hidden cracks after wear. When taken up to relay, it is often found that a stone which was apparently sound, breaks before it can be relaid. Concrete pavements in situ have the serious disadvantage that they cannot readily and cheaply be repaired. A patch in them shows for the whole life of the pavement, unless a whole bay is removed. The writer is of opinion that concrete pavements in situ are preferable to concrete pavements laid as slabs. There is, however, no reason why this pavement should not be laid by surveyors them- selves, without the aid of a contractor. Much has to be learned before concrete as a material for foot-pavements is perfected, but that can most readily be learned by each engineer doing his own work, and exchanging experiences. The prices paid for concrete pavements are very great. One stone is advertised for 7 a 7 , per square foot, which equals 4 145-. 6d. a cubic yard. This is an extravagant price to pay for concrete, even if it be of the very best kind, and silicated, too. Concrete for foot-pavements has its own field, and within well-marked limits its use is advisable, but until its capabilities are more largely tried and its usefulness increased, the full advan- tage will not be obtained from it. The price stated is large enough CURBS, SIDEWALKS AND TRAMWAYS. 205 to cover the cost of experimenting, and the writer trusts that the members will carry out such a series of tests and trials as will com- plete the knowledge of concrete as a material for foot-pavements. Discussion. A Remedy for Cracks. In the discussion following the reading of Mr. Strachan's paper on "Asphalt and Concrete Foot Pavements," we learn from the Builder s report that Mr. Vawser, of Manchester, mentioned the advantage which was experienced at Macclesfield by laying concrete footpaths in about 4-foot squares, and putting between each a piece of plank. It was found that the elasticity of the planking was sufficient to prevent any cracking. Mr. Fowler, of Manchester, agreed as to the great value of con- crete paving, which, seven years ago, he used for the Newcastle Cattle Market. There he placed a lath round the boundary of each section, and there was not a single crack. Mr. Ellice Clarke, of London, said his experience of an asphalt footpath \ -inch thick was that at the end of three years it required very considerable repairs. The unsightliness of cracks in asphalt was their principal objection ; they did not detract at all from its wearing well. The practice mentioned by Mr. Vawser had been discontinued by all who had had much experience of asphalt. Now it is usual to lay two slabs of concrete on alternate days, or two or three days. Mr. Boulnois, of Portsmouth, said that some of the earlier samples of ferrumite stone had too much iron in them, and being thus too hard, had a very slippery surface. The secret of the wear of asphalt lay in a nutshell. Unless it got sufficient traffic upon it it would never consolidate properly. Mr. Lemon, of Southampton, said that twenty years ago he was very enthusiastic about asphalt, and his Corporation laid a great deal of it down. He had come to the conclusion now that there must be a very large traffic over it, or at least sufficient to keep it together, otherwise it was bound to fail. Some laid down 2-inch thick soon wore out, but some laid 2 inches thick in a roadway where there was great traffic had been down for fifteen years, and had never cost sixpence for repairs; With respect to concrete, he thought concrete made and laid in situ was the footpath of the future. TRAMWAYS. LIVERPOOL TRAMWAYS.* Tramways Built by the City. We propose in this and subsequent articles to give quite full details of the important work under this head that has been done in Liverpool. The contrast of methods in the construction of tramways, as compared with those usually pur- *xiv, 369. 206 CURBS, SIDEWALKS AND TRAMWAYS. sued in this country, is violent. As will be seen, instead of these important franchises being given away, as they are in our large cities, the city of Liverpool builds the roads and leases them at the hand- some figure of about eight per cent, on their entire cost. Their Extent and Cost. The change in the method began in 1880, when the city, under powers granted by Parliament, purchased the then existing lines. Since that date the lines have been ex- tended, until now the total length of single lines is 45! miles. In connection with the construction of the lines 198,452 square yards FIG. i. LAYING THE ROAD. of stone block paving within the statutory width has been set on a foundation of Portland cement concrete, and the total cost, including engineering and other incidentals, has been $1,394,736, or $30,486 per mile of single track. The whole street has also been paved in tramway streets, requiring in all about three times the amount of pav- ing mentioned, and the monthly progress has been about one mile of tramway and 13,400 yards of "impervious" paving, all executed by corporation workmen under the supervision of the City Engineer, Mr. Clement Dunscombe, M. I. C. E., and staff. CURBS, SIDEWALK AND TRAMWAYS. 207 Construction. In doing the work all old stone blocks were taken up and redressed, occupying forty-two stone-dressers. The fragments and waste were used in concrete, and in the cost given the value of all old material is included. Prior to 1879 the reconstructions and extensions were made on the system of Mr. Deacon. Since that time they have been made on a modification of this known now as the "Lyver" system. The cost of maintenance is spoken of as very small. Figure i is a general view showing the work of laying the road in progress. Figure 2 shows a longitudinal elevation of the rail. In constructing the work the street is fully excavated to a depth determined upon as it progresses. A bed of Portland cement con- crete is then formed to within 7* and 6| inches respectively of the finished roadway. The concrete is made of one part by measure of cement, six parts of gravel, and eight parts of broken stone. The LYVER- SYSTEM. SIPE ELEVATION. F D E A FIG. 2. cement is first mixed dry with four times its bulk of gravel and then wet and mixed with the remainder, only water enough being added to make the mass just adhere together when pressed in the hand. On the bed prepared for the concrete, molded blocks of Port- land cement concrete, eight inches square at the base, are laid with their upper faces on a level with the under side of the sleepers B (see Fig. 3, which is cross-section of one rail). The sleepers are then laid on the blocks, the rails A being placed on them, and the wrought-iron jaws C secured to the rails by bronze bolts D and wrought-iron nuts E. A small space is maintained by temporary washers between the upper surfaces of the jaws and the rails. As soon as the rails are leveled up and in proper position the concreting is proceeded with up to the level of the bottom of the sleepers, as shown. After the concrete is set the bolts are unscrewed, the tem- porary washers removed, and the rails A and sleepers B firmly screwed down to the jaws. The recesses or hand-holes are then completely filled with plaster-pitch which keeps the nut E from turning round. 208 CURBS, SIGEWALK AND TRAMWAYS. The jaws are placed three feet between centres, except at the ends of rails, where the space is nine inches. Points and crossings are of annealed crucible steel, secured to special cast-iron sleepers, a layer of roofing-felt being laid between them and the sleepers. Paving the Roadway. Between the rails, and for 18 inches on either side, the roadway is paved with syenite blocks. The blocks are cut 3^x5 to 7 inches, and in two depths viz., 6] and yj inches also 3jx3*x6J inches deep. They are squared throughout, accu- rately gauged, with a maximum allowed variation of one-quarter of an inch, and laid in straight and properly bonded courses on an ENLARGED SECTION. FIG. 3. even bed of fine gravel not exceeding half an inch thick. After paving, the joints are filled with clean dry shingle passing through a I -inch sieve and retained by a f-inch sieve. The sets are then rammed and new shingle applied until the joints are full, after which they are grouted with hot pitch and creosote oil of the best quality and covered with half an inch of sharp gravel. Along each side of the rail there is laid a course of alternate long and short blocks, shaped in plan as shown in Fig. 4. These are finely cut on the side next the rails so as to make close contact ; they are also cut to touch each other for one and a half inches from the rail. CURBS, SIDEWALKS AND TRAMWAYS. 209 The weights per mile of single track are given as follows : Bessemer steel rails, 40 Ibs. per lineal yard. . . j . . . 62.8 gross tons. Cast-iron sleepers, 80 Ibs. per.lineal yard 125.6 f? " Wrought-iron jaws, single, 4.28 Ibs. each H5-5 cwt. Wrought-iron jaws, double, 10.5 Ibs. each 35.5 " Bronze bolts, 4 ozs. each 9-83" Wrought-iron nuts, 5 ozs. each 10.5 " PLAI* or 8-sciAL SET G PLAN |v^ #jl v 3** //' -J J/" ^- J M y/ FIG. 4. Testing Materials. The Portland cement was all tested. A 5o-gauge wire sieve (2,500 meshes per square inch) must not return more than 10 per cent. When tested neat, after twenty-four hours' immersion in water, it must stand 1,000 pounds on 2\ square inches. Slow-setting cement must take an impression from a needle having an area of ^J-^ of an inch, and loaded with 2\ pounds, at any time within three hours after molding, and quick-setting cement must give an impres- sion at any time within half an hour. The Bessemer rails were tested by the drop test. With groove upward, rail supported at three feet between supports, weight 2,240 pounds, dropped ten feet, the average deflection was 8.51 inches and none were broken. Tensile tests were made on pieces 18 inches long cut from rails. Allowed limit twenty-eight to thirty-two gross tons per square inch, with elongation of 20 per cent, on 6J inches. The average strength was 31.62 tons, and elongation 22 J per cent. Hot bending tests by heating to cherry red and cooling in water at 80, and bending afterward double, to a curve with inner radius of three times the thickness of specimen, gave no fractures. Short lengths were bent cold under steam hammer to a radius of six inches. Deflection tests, with supports three feet apart, showed maxi- mum elasticity of 10 tons and a minimum of 5 tons. 2IO CURBS, SIDEWALKS AND TRAMWAYS. Cast-iron was tested on supports three feet apart, bars one inch square to support a centre load of 800 pounds. The maximum was i, 800, minimum 640, and average 960 pounds. Two per cent, of the bolts were tested by a load of three tons, the nut being turned while the load was on, about 4 per cent, fail- ing under test from inferior workmanship. Sample nuts were tested by heating to a cherry red and flatten- ing on an anvil. The result of reducing the thickness from one inch to one-eighth of an inch was to show no splitting at the edges. CHAPTER VI. STREET OPENING. MAINTENANCE. LIVERPOOL STRFET EXCAVATION CONTRACT.* Excavation of Trenches for Electric Supply- Tubes and Temporary Reinstatement of Pavements. Clement Dunscombe, M. Inst. C. E. y City Engineer, July n, 1888. FORM OF TENDER. To the Chairman of the Health Committee, Liverpool. SIR : We hereby agree to execute and perform such works as may from time to time be ordered in writing by the City Engineer in connection with the excavation of and reinstatement of pavements in Liverpool, consequent upon the operations of the Liverpool Electric-Supply Company, under their license, at the rate of the several prices we have affixed to the items in the annexed schedule, duly signed by us. And further, we are prepared to enter into a contract for the due fulfillment of the work in accordance with the annexed specification. propose Mr of and Mr of as proper persons who are willing to be bound as sureties for the due performance of this con- tract in accordance with the terms of this specification. We are, Sir, Your obedient servants, Signature Address Date SCHEDULE OF PRICES REFERRED TO IN THE ANNEXED TENDER. Prices inclusive of all charges whatsoever per lineal yard of trench two feet wide, and given separately for each of the following conditions and depths, not exceeding 3 feet, 3 feet 6 inches, 4 feet, 4 feet 6 inches or 5 feet. Footways. To take up the pavements and curbs in footways where required, excavate trench for pipes, fill in and ram the ground over pipes, and temporarily relay the footway permanent and where disturbed. Carriageways. To take up the channels or impervious pavements, excavate the trench through the cement or bituminous concrete foundation as required for laying the pipes, fill in and ram over pipes, and temporarily block in the pavements. The same with impervious pavement in hand-pitched rock foundation. The same with gravel jointed set pavement on hand-pitched founda- tion. The same with macadam on hand-pitched foundation. The same with boulder pavement on hand-pitched foundation. Extra excavation for connections or other necessary works measured at the time of execution of any of the foregoing depths, per yard, cube. Add extra for work done at night, as per Clause 8. Signature Address Date *xviii, 293. 212 STREET OPENING. SPECIFICATION. 1. Interpretation. In this specification the word "engineer" shall be held to mean the City Engineer of Liverpool for the time being, and the word " assistant " shall be held to mean the person whom the engineer may appoint from time to time to superintend the works, 2. Extent of Contract. This contract comprises the execution of such works as the City Engineer may from time to time order in writing in con- nection with excavation of trenches for laying electric supply tubes under the public highways in the city of Liverpool, for which the Liverpool Elec- tric Supply Company possess a license, and the reinstatement of such trenches and pavements as specified and any other works as may be required in connection therewith. 3. Excavation of Trenches and Reinstatement of Pavements. The contractors shall, upon receiving notice in writing from the City Engineer, forthwith proceed to take up the existing pavements, concrete or other foundation where required for laying the electric supply tubes authorized by the Liverpool Electric Lighting License, 1888, and they shall carefully place on one side these materials until the pipes are laid. They shall then exca- vate to the required depths, and after the electric supply tubes are placed in position, fill in and well ram down, in layers not exceeding six inches deep, the trenches with the excavated material, watering the same where neces- sary in order to thoroughly consolidate it, and when the filled-in material is thoroughly consolidated the pavement over the trenches and also any flag- ging disturbed shall be temporarily reinstated. All surplus excavation and rubbish shall be removed by the contractors, on completion, and the surface left clean and in such a condition as shall be safe and free from danger to both vehicular and pedestrian traffic. 4. Tools, etc. The contractors shall provide all materials, labor, tools, tackle, implements, etc., for the proper execution of the works executed under this contract, and shall pay or provide for all carriage and cartage of materials. The contractors shall exercise every care and precaution in taking up the existing pavements so as to cause as little damage as possible to the materials so removed, and any new materials that may be required shall be the best of their several kinds, and the same shall be applied in the most workmanlike and substantial manner possible and to the entire satis- faction of the engineer. 5. Contractors to Pay Fees and Make Good Damage, etc. The contractors shall pay all fees and compensations, and make good at their own expense all damages of every kind which may occur by reason of the execution of the works for the performance of which the contractors are bound. 6. Fencing, Hoarding, Watching, Lighting, etc. The contractors shall provide, make and maintain all necessary fencings, hoardings, strut- tings, shorings and bridgeways, temporary or otherwise, as may be neces- sary for and in consequence of any of the works. They shall also properly light and watch all the works in accordance with the requirements of the Public Health Act 1875, and to the satisfaction of the City Engineer and the police of the district. 7. All works shall be carried on in such a manner as to cause the least inconvenience to abutting occupiers, and in such manner lengthwise and widthwise as the engineer may direct, and which will least impede the busi- STREET OPENING. 213 ness of the neighborhood and the public traffic, and so as not to obstruct or endanger pedestrians, animals or vehicles. 8. The contractors shall, on receiving notice from the City Engineer, execute such sections of the work as may be considered desirable to be so executed during such hours of the night and early morning as may be pre- scribed by the City Engineer in such notice, and the same shall be paid for in accordance with the schedule attached to the tender without any further amount being chargeable beyond the sums therein stated. 9. Screens. If the contractors shall neglect in any case to provide a suitable screen or screens wherever stones are being chipped for the pur- pose of protecting pedestrians they shall pay to the corporation as and for liquidated damages the sum of ^i per day for every day on which such de- fault shall have been made, and the Corporation may deduct the same from any moneys in their hands due or to become due to the contractors. 10. Notice to Gas Company and Water Committee. The contractors shall give due and sufficient notice to the gas company and water commit- tee in order that the proper persons having charge of the mains, services, etc. , may be enabled to attend and see that the said pipes are secured, relaid and reinstated in a proper and satisfactory manner, the contractors nevertheless to execute or pay for executing all such alterations and rein- statements and to be held chargeable and responsible for the proper pro- tection and restoration of the same at their own expense. 11. Facilities to Gas Company and Water Committee. The con tractors, if so ordered by the engineer, shall allow the gas company and water committee by their workmen or agents to enter upon the site of the works for the purpose of relaying the gas and water-mains and services without any extra charges being payable by the Corporation. 12. Measurement of Work. The contractors, their agent or fore- man, shall attend weekly at such time and place as shall be named by the engineer for the purpose of measuring and ascertaining the quantity of work performed, and in default thereof the engineer shall be at liberty forthwith to measure and ascertain the quantity himself, and his decision as to the quantity shall be final, binding and conclusive upon all parties. 13. Subletting. The contractor shall not assign or underlet or make over this contract, or any benefit or interest thereunder, to any other person without the consent in writing of the engineer. 14. Occupation of Site of Works. The Corporation may, for any pur- pose, or at any time during the continuance of this contract, occupy any part of the site of any of the works simultaneously with the contractor for the execution of any works whatsoever without any compensation being payable to the contractor. 15. No Claim to be Made for Delay. The contractors shall not be entitled to compensation should any portion of any of the works be delayed in its execution from any cause whatsoever. 16. Rxtra Works. No allowance shall be made to contractors for any alteration in or addition to the work specified unless they can produce a written order of the engineer for the same. 17. Disputes. If any dispute or differences arise during the progress of this contract or afterwards respecting the true intent of this specification the same shall be referred to the engineer, whose decision shall be final and binding upon all parties concerned. 214 STREET OPENING. 18. Instructions. The engineer shall have full power to issue such further instructions from time to time as he may deem necessary for the guidance of the contractors, and the contractors shall be bound by them. 19. Expedition in Carrying on Works, Failing which Corporation may Employ other Contractors. The contractors shall commence and carry on the works specified herein with due diligence and as much expe- dition as the engineer may require, and in case the contractors shall fail to do so, or shall neglect to provide proper and sufficient materials, or to sup- ply a sufficient number of workmen to execute the works which they shall be ordered to execute with due diligence or the dispatch required, then the engineer shall have full pow r er without vitiating the contract, and he is hereby authorized to take the works, wholly or in part, out of the hands of the contractors and to engage any other person or workmen, and procure all requisite materials and implements for the filling in of the trenches opened up by the contractors whether the mains are laid or not, and the reinstatement of the pavements disturbed by their operations and due exe- cution and completion of any works requisite in connection therewith, and the costs and charges incurred in so doing shall be ascertained by the engi- neer and paid for or allowed to the Corporation by the contractors, and it shall be competent to the Corporation to deduct the amount of such costs and charges out of any moneys due or to become due from them to the contractors under their contract, or in case there is no money due or to become due to the contractors, then the Corporation may recover such costs and charges by action at law or otherwise. 20. Openings for Examination. Should the engineer or his assistant require it for his more perfect satisfaction the contractors shall, at any period during the continuance of this contract, make such openings and to such extent, through any part of the said works, as the engineer or his assistant may direct, and which the contractors shall make good again to his satisfaction at their own expense. 21. Superintendence, Skilled Workmen. The contractors shall em- ploy only such foremen and workmen in or about the execution of any of the works under this contract as are careful and skilled in their various trades and callings ; and the engineer shall have full power to object to or dismiss any person who shall be found incompetent or who shall act in an improper manner. The contractors shall also have a competent representa- tive upon the works. 22. The Contractors to Suspend any Works when Ordered. The contractors shall suspend the execution of any work when ordered so to do in v/riting or otherwise by the engineer, and whatever expense may be occasioned by the suspension of the works shall be paid by the contractors and without charge to Corporation ; and the engineer shall have full power to direct any alteration in the manner of carrying on or finishing any such work, matters, or things, without thereby in any way affecting, vitiating or impairing the tenor or force of this contract. 23. Precautions Against Accidents or Injury, Corporation and Officers to be Indemnified Against Action, etc., Corporation -may Compromise Actions, etc. The contractors shall take every necessary, proper, timely and useful precautions against accident or injury to the works, or any of them, or to any other property or to any person, by the action or pressure of water, and whether the same shall arise from or be occasioned by floods, springs, rains, streams, accumulations, disruptions, STREET OPENING. 215 leakage, frost, or other natural or artificial causes whatsoever, and shall forthwith repair, make good and defray any loss, damage, cost, charge or expense, by, or in consequence of any accident, or by, or in consequence of the operations of the contractors occasioned to the Corporation or to the said works, or any of them or to any person or persons injuriously affected thereby and shall indemnify, save harmless and keep indemnified the Corporation and their officers from and against the same, and from and against all actions, suits, claims, penalties, liabilities, costs, expenses, and demands whatsoever by reason or on account thereof, and also from and against any claims for compensation under the provisions of the Employers' Liability Act, 1880, and the Corporation may deduct the expense thereby incurred, or to which the Corporation and its officers may thereby be put or be liable, or which may be incident thereto, from the amount of any money which may be or become due or owing to the contractors, or may recover the same by action at law or otherwise from the contractors ; and the Corporation may, if they shall see fit, compromise any such action, suit, or other proceeding, or any claim in respect of any such damage as aforesaid on such terms as they shall think fit ; and the contractors shall thereupon forthwith pay to them the sum, or sums paid by the Corporation on the occasion thereof, and shall in every case pay to them such sum or sums as shall fully indemnify them according to the present stipulation. 24. Responsibility for Accidents, etc. The care of the entire line of works in each case shall until their permanent reinstatement by the Corpo- ration remain with the contractors, who will be held responsible for all acci- dents from whatever cause arising, and for the making good of all damages and defects to the said works from bad or insufficient materials, bad work- manship, or any cause whatever. 25. Payment. That subject to the conditions in this specification con- tained, payment shall be made to the contractors monthly upon the certifi- cate of the engineer, and within three weeks from the date thereof at the rate of 75 per cent, on the value of the respective works executed as assessed by the City Engineer, and the remaining 25 per cent, within two months after the permanent reinstatement by the Corporation of the respective pavements disturbed, on condition that the terms of the contract shall have been fulfilled and upon the certificate of the engineer of the amount to which the contractors are entitled, and that the work has been executed to his satisfaction. 26. Default of Contractors to Comply with Specification. The pay- ments hereinbefore mentioned are subject to any deductions for expenses or costs to which the Corporation may be put in consequence of default on the part of the contractors to fulfill the terms of this specification. 27. Tenders not Necessarily Accepted. The Corporation do not bind themselves to accept any tender, or to pay any expenses incurred by parties tendering, and reserve to themselves the right not to order any of the works herein contracted for. OPENING AND REINSTATING PAVEMENTS IN LIVERPOOL.* We would call the particular attention of our readers to what Mr. Dunscombe, City Engineer of Liverpool, says below on the sub- * xv, 485. 2l6 STREET OPENING. ject of reinstating pavement over trenches and opening up of pave- ments : " In cases where trenches are required for gas and water purposes, notice is given by the company to me; the trench is then opened by the company's workmen, and upon completion of the work the trench is filled in by them and the paving is also temporarily blocked in at the company's risk. The pavement is then reinstated in a permanent manner by Corpo- ration workmen, and the cost of the same and charges incidental thereto charged to the company. The Corporation execute this work as contractors only, and the company are liable for, and are actually charged, the cost of any repairs necessary during a period of six months in order to maintain the surface in a perfect condition. " By written permission of the Corporation only, openings in the pave- ments are allowed to be made for the purpose of examination of private drains, and no other interference with the pavements is allowed, either in the carriageways or footways, except under Parliamentary powers obtained for the execution of the work, in which case ample protective clauses in the Act of Parliament are obtained by the Corporation, dealing with the con- ditions upon which any undertaking shall be allowed to in any way inter- fere with the streets or pavements. These clauses are comprehensive and fully protect all interests of the Corporation against any undue interference with the streets, and provide for their reinstatement, in a proper manner, at the sole cost of the promoters, in cases where such interference is per- mitted. " Interference with the pavements in Liverpool is of rare occurrence, inasmuch as both the gas company and the Water Committee of the Liver- pool Corporation thoroughly examine and reinstate where requisite their mains and seryices concurrently with the repaving of a street, of the exe- cution of which due notice is given to them by my department. In no case would streets be allowed to be opened up so as to prevent the free passage of traffic along it, except in cases of the most extreme urgency, and even in these cases the local police authorities would regulate it, and the pro- moters of any undertaking would not be allowed to interfere at all with the streets and roads except under the most stringent regulations. The street traffic is a matter which receives the first attention at the hands of the Municipality, as any interruption of it would be attended with serious in- convenience and loss." HOW TO PRESERVE OUR PAVEMENTS.* In his address to the new Board of Aldermen of this city, Pres- ident Beekman made the following reference to the continual de- struction of our pavements : " The condition of the pavements of the streets and avenues in various portions of the city has long been a well-founded subject of complaint. " Under authority from the Legislature various private corporations, in furtherance of their business objects, are constantly removing the pave- ments and excavating in the public streets. "The result of this is that the pavement, insufficiently restored, be- comes depressed, holes, ruts and channels are formed, and an irregular sur- *Ed. xv, 179. STREET OPENING. 2i; face is occasioned over which it is painful to travel, and which collects in- stead of shedding water and waste material. " While, no doubt, the convenience and comfort of the public are greatly increased by the advantages which these companies afford in their particu- lar line of business, it is quite certain that the privileges they enjoy are of exceptional value, and it can be no hardship to require of them all the speed' care, and skill that can be exercised in the rapid and satisfactory completion of their work. " While this Board possesses no power to prevent the use of the streets for such purposes, it may at least pass reasonable rules and regulations, as it has in some measure in the past, defining the manner in which such ex- cavations may be made and the street surfaces properly and permanently restored. Having determined upon the most approved methods of doing such work an ordinance should be passed strictly enforcing compliance with such methods and requiring the greatest expedition in performing the work too often protracted beyond a reasonable time for its proper execution.', What he said may be news to an alderman, but it is no news to any engineer or any one having the slightest familiarity with muni- cipal engineering. It is our deliberate opinion that no matter what ordinances may be passed, what regulations adopted, or however good the inspection may be, the pavements of this or any other city will never be in decent condition until all removals and restora- tions of pavements are done solely by the city's own employees and agents, for which work any corporation or individual who desires the streets to be disturbed should be compelled to pay the cost ; and that cost should be sufficient to secure thoroughly sound work and also the cost of a reasonable maintenance. We are under the im- pression that this is the practice in Liverpool, if not in other foreign cities, and by this means, and this means only, will people avoid the opening of a street except in most imperative cases. Indeed, there are many occasions on which a street is now torn up, when, if there was a sufficient tax placed upon such tearing J up, the parties inter- ested would find some way of tunneling or accomplishing the pur- pose without a disturbance of the surface. ON OPENING UP PAVEMENTS.* It is reported that a movement is on foot to secure legislative authority to repave a large number of streets in this city, the work to be under the control and direction of General Newton, Commis- sioner of Public Works. We hope it may be successful. The Sam. tary Engineer and Construction Record has for some time been print- ing articles describing notable examples of pavements in other cities, and a person only needs to read these, even if he has not an oppor- tunity of visiting other cities, to become convinced of the wretched character of the pavements of this great city. If authority is granted * Ed. xv, 370. 2l8 STREET OPENING. General Newton's department to construct these pavements, and there are no needless conditions inserted in the act to tie the Com- missioner's hands, we believe New York City will secure good pave- ments and at a moderate price. But these good pavements cannot be maintained unless additional powers are granted to the Depart- ment of Public Works, which will prevent in future any disturbance of them, except by the servants of this department and under its direction, such disturbances to be paid for by the companies, who- ever they may be, in whose behalf the pavements are taken up. This city badly needs pavements, but if it is to retain any worthy of the name, after they are laid, some check must be placed upon the gas, steam and electric-light companies, who would otherwise keep them in a constant state of eruption. THE REPAVING REQUIREMENTS OF NEW YORK CITY.* We give herewith a brief report of the preliminary meeting of the Committee appointed by the New York Chamber of Commerce to confer with the authorities of that city to ascertain in what direc- tion they can best co-operate to secure the repavement of its business portion. The disabilities under which the authorities now labor will doubtless be plainly brought out by this public action of the Chamber of Commerce. It is a hopeful sign that this influential body pro- poses to interest itself in a movement to put an end to the disgrace- ful condition of the streets of New York, and it is highly important that there should be concerted, intelligent action on the part of all good citizens, except the directors of surface railroads and corpora- tions, who are constantly disturbing the streets without any regard to the convenience of the community and the pockets of taxpayers, and who hitherto have never failed to look out for their immediate inter- ests, as has been frequently pointed out in these columns. Four things will have to be decided upon, and until they are done it seems useless to spend any money for new pavements. First. The pres- ent form of street-rail should be abolished, and not another length of it should be permitted to be laid. Second. Paving of every por- tion of a street should be done by the city authorities, or under their direction and control. Third. No openings should be made in the pavements except under permits granted by the Commissioner of Public Works, which permits should state definitely the exact loca- tion and limits both of time and space within which the opening can be made. Fourth. All restorations should be made by the Depart- ment of Public Works or under its immediate direction, the cost of which should be paid by the corporation or individual for whom the pavement was originally disturbed. This latter requirement is uni- *Eo. xvii, 31. STREET OPENING. 2IQ versal in every city in Europe that pretends to have a pavement worthy of the name. Without it responsibility cannot be placed on any one, nor is it possible to secure by present methods anything but the most worthless and inefficient work. As has been pointed out in the series of articles on "Pavements and Street Railroads," now appearing in The Engineering and Building Record, the custom abroad is to have corporations, like gas or water companies, who have occasion to frequently disturb the streets, leave a regular deposit with the department. Against this deposit charges are made for each piece of paving done at a fixed price per yard, according to the kind of pavement. Where special openings are made special deposits are required. The department in charge of streets, when it issues a permit for an opening, requires the space to be inclosed by means of iron pins and a rope, from which lanterns are suspended at night, and if it is a street which has a concrete foundation under the pavement, time is taken to allow the concrete to properly set before the pavement is relaid. When the necessary authority is given to the proper officials to institute and maintain the reforms here out- lined, pavements suited to a civilized community may be secured and retained. To that end it is to be hoped the influence and co- operation of the Chamber of Commerce may be effectual. The committee appointed by the New York Chamber of Commerce to confer with Mayor Hewitt and General Newton as to what steps could be taken in order to best co-operate with the authorities in securing new pave- ments for the business portion of this city, met by appointment in the Mayor's office on December 9. The committee consisted of Messrs. Fran- cis B. Thurber, Secretary George Wilson, Silas B. Dutcher, James H. Sey- mour, Thomas Rutter, and Henry C. Meyer. General Newton, Commis- sioner of Public Works, presented a statement prepared by one, of his staff, who had made a survey of the down-town streets, which indicated that 536,527 square yards of street surface required repaving, at an esti- mated cost of about two millions of dollars. Mayor Hewitt expressed him- self as in favor of authorizing a loan of about five millions, to be expended by the Commissioner of Public Works, subject to the approval of the Board of Estimate and Apportionment, for repaving the streets of this city, provided authority were given the Department of Public Works to compel railroad and other corporations to obey its order with regard to the opening of streets and the obstruction of them by needless street rails put down by railroad companies to hold a charter, but on which they never ran cars. The Mayor cited the aggravated case of the corporation who have rails in Fulton Street. The impossibility of properly doing anything until the authorities had power to control the action of corporations who get grants from the Legislature or Aldermen, and consequently ignored the authorities, was made manifest. A member of the committee urged that all pavements when opened by corporations or other parties, should be restored by the department's own servants, the cost of such restoration to be paid by the parties having the streets opened ; the amount of space to open at one time, duration of time of such opening, where traffic should 22O STREET OPENING. be suspended, should also be subject to the discretion of the Commis- sioner of Public Works. On this point the Mayor said that the Corpora- tion Counsel would be asked to see if further legislation was necessary to give such power to the Commissioner. Pending the securing of the needed legislation suggested , the Commissioner of Public Works proposed to sub- mit a list of the streets that most imperatively needed pavement to the members of the committee, and expressed himself as desirous of expend- ing the $500,000 appropriated by the Board of Estimate and Apportionment on such streets as the committee should agree most needed it. After assur- ing the Mayor and the Commissioner that the Chamber of Commerce would heartily co-operate with them in a movement to secure better pavements for this city, the meeting adjourned for further conference when the data promised by General Newton should be prepared. A MOVE TO PROTECT OUR PAVEMENTS.* We are heartily glad to at last see a move made toward stop- ping the irresponsible tearing up of New York streets. The Park Board has adopted a resolution under which all gas and electric companies, sewer builders and the like, applying for permission to tear up the streets for any purpose, will be compelled to deposit a sum of money equal to the original cost of the pavement, to be held until the roadway is restored to good condition. This is precisely what we have been urging for years, and the soundness of the principle and the necessity for action cannot be questioned. All other city authorities should promptly follow the example, which, however, does not go far enough, since the work of restoration should, as we have before stated, be done by the city's own employees and under the direction of its engineers, the cost to be paid out of this deposit, which should be more than original cost of pavement. It is easier to get good work that way than to wrangle with the contractor of the parties who rip up the streets. MAINTENANCE OF PAVEMENTS IN LONDON. f St. George s Parish. From a report by Mr. George Livingston, C. E., Surveyor of St. George's, Hanover Square, London, we gather the following : There are forty-two miles of paved streets in the parish. With the exception of Piccadilly and two miles paved with other materials, all of these are macadamized, the road metal consisting either of granite, flints, or gravel, The labor of maintenance is performed by what is called a "lifting" gang, the men being paid fourpence per hour. The engineer and stoker of the road-roller receive more. This gang is supplemented for a part of the year by men called " district roadmen." The average annual cost of maintenance of the macadamized streets, based on the traffic and cost of the past five years, is estimated at 2s. bd. * Ed. xx, 268. f xvii, 84. STREET OPENING. 221 per yard for the future, and the estimate for granite, including renewal in thirty years, is a trifle more than one-half as much. The addition of cost of cleansing in each case would make the disparity still greater. Systems of Maintenance. Four systems of maintenance and repair are discussed : First By contract under fixed prices for labor and materials. The difficulties of determining the exact condition the streets shall be in at the expiration of the contract, and of getting efficient contractors is dwelt upon. The convenience of a large staff of workmen is also mentioned. Second By piece-work or part contract. The Vestry would by this supply the materials and the contractor the labor and tools. Third By a superior class of men in the employment of the parish. This is essentially the present plan, except that by offering a higher price for labor better men would be obtained. Fourth By the substitution of a different description of pavement. Street Cleaning. Street cleaning is considered one of the most impor- tant matters to deal with. It is done in part by contract and in part by the parish staff. There are in the employ of the parish in the "inwards" twenty-two men, one foreman, and a sweeping-machine. Men are paid 2s. 6d., foreman 3$. 6d. per day, beginning at 4 o'clock in the morning in summer and 6 o'clock in the winter. Sweepings are removed by carts as soon as possible. The sweepers are mostly paupers and cost more on account of small quantity of work done than a better class of labor. Hav- ing no water- proof clothing furnished them, no work is done in wet weather. In the out wards there are thirty-two districts, in each of which a roadman sweeps the crossings and collects the refuse by barrow for removal by the carts. He also does all repairing needed. The total annual cost for cleaning the streets is about jio,ooo. " Notwithstanding this large outlay, the streets of the parish (in the opinion of the committee) continue to be most inefficiently cleansed. The nuisance most complained of is, that the mud is swept from the centre and deposited in large heaps at the sides of the road in or near the channel, where it is left for an unreasonable time to the great inconvenience of the public. The simple cause of this is that the streets which have been swept yield a greater quantity of mud than can, by the present system, be removed. This is due chiefly to an insufficient staff of horses and carts to remove the slop and the difficulty attending its ultimate disposal. Any increase, therefore, in the staff necessary to perform this work more rapidly must entail additional expense. ' ' The difficulties in the way of a speedy cleansing of the streets, how- ever, under existing circumstances are numerous. The chief are : 1 ' First The nature and condition of the pavement to be cleansed. " Second The imperfect method of sweeping. " Third -The amount of mud to be removed. " Fourth The objectionable and dilatory method of removal. The cleansing of the streets, both as regards its cost and efficiency, depends, to a very great extent, upon the description of pavement of which they are composed ; and it cannot be disputed that macadamized streets (such as most of the thoroughfares of this parish), subject to heavy traffic, yield a much greater quantity of mud than any other pavement. For exam- ple, the average quantity of slop removed from the macadamized portion of Piccadilly (previous to its being paved with wood), between Engine Street 222 STREET OPENING. and Hyde Park Corner, comprising an area of about 8,600 yards, was sel- dom less than from 25 to 30, and frequently as much as 40 cart-loads a day in wet weather ; notwithstanding this, the roadway was never in a satis- factory condition. Whereas, since it has been paved, the average quantity of slop removed, under equal conditions, -from the entire length of the road- way nearly three-quarters of a mile representing an area of about 20,000 yards, does not exceed 12 cart-loads a day, the greater portion of which is a valuable manure. Every one who has observed the roadway under the two conditions of pavement must be sensible of the vast improvement that has been effected. I have no hesitation in saying that Piccadilly, which was formerly one of the worst kept and filthiest roads in the parish, is now, considering the labor employed, one of the handsomest, cleanest, and best kept thoroughfares in the metropolis. The surface of streets, under certain conditions, is frequently covered with a thick, sticky, greasy mud, due to various circumstances, the state of the atmosphere, the situation of the street, and the influence of wind and sun, etc., which the present system of sweeping, especially on macadam, utterly fails to remove, and which is the occasion of serious accidents. According to some returns of the Registrar-General, the average annual number of persons killed in the streets of London is about 200, and the number injured by accident about 2,000. The greasy and slippery state of the streets is often the cause of these casualties. The macadamized roads, also, at times, are "permeated with the solu- tions of the surface dung deposits, and become excrement sodden," the dry decomposition of which neither the broom-sweeping nor the scraper can wholly remove ; and the moist exhalations produced by street-watering (during the process of evaporation), especially in hot weather, are most offensive. As a matter of public health and safety, therefore, the perfect cleansing of the roads and streets is most essential. The quantity of mud and slop to be removed from the streets depends entirely upon the condi- tion of their surface and the nature of the weather ; and the accumulation swept from the streets of this parish, which averages about 30,000 loads a year, is so great that its speedy removal from all the streets is, under pres- ent arrangements, impossible. This is, in great measure, due to the fact that the entire bulk, after having been scooped up in shovelfuls, has to be removed by horses and carts. A more filthy, more costly, and less speedy method of street cleansing cannot be well imagined, and there are many who regard it as discreditable to the sanitary arrangements of this capital. If the cleansing of the streets is continued to be done on the present principle, there is an obvious remedy for the evils complained of, provided the necessary expense is incurred. Suppose, for instance, it is required to have the whole of the streets in the parish cleansed by a certain hour in the morning (say 10 o'clock), all that would be necessary would be to employ a sufficient number of men to sweep the mud and dirt from the streets before that time, and to make it imperative upon the contractor to remove it ; but the cost of providing such a staff would be serious. In cleansing thoroughfares, especially those of great traffic, speed and efficiency are of the first importance ; any scheme, therefore, to be proposed for the better cleansing of the streets must have regard to such results. One method which I venture to suggest, by which this might be effected would be by fixing in each of the principal streets of the parish a number of hydrants, STREET OPENING. 223 at convenient distances apart, to which suitable lengths of hose-pipe could be attached. By this arrangement, the whole length of a street could be thoroughly cleansed in a comparatively short time, and after the street had been washed by the application of water in this manner, and swept by an India-rubber broom or squeegee, made on the principle of the present horse-scraper, so as to remove any wet or moisture from the surface, it would be rendered perfectly dry and free from every description of filth. Street- Washing. Under existing arrangements, the sweepings of the streets (as before stated) are removed by contract, and it is naturally the object of the contractor in performing this work to avoid as much cartage as possible; consequently, in wet weather, the mud and slop are of ten either left at the sides of the streets, or are, as is frequently the case, when oppor- tunity offers, swept into the gullies. The adoption of the hose-pipe, how- ever, would dispense almost entirely with scavengers, and also with the annoyance and labor of cartage ; for, by the application of water, the sweepings of the streets would be put in such condition as to cause them to pass off immediately into the sewers. The passing of this liquefied mud through the sewers might be con- sidered objectionable, as being likely to choke them up. I am of opinion, however, that, so far from creating any stoppage in the sewers, the opera- tion would be most beneficial, as it would have the effect of flushing them. This hose or jet system is not new ; and Mr. Heywood, the City Engineer, who tried it, states with reference to the effect it had upon the sewers that " during the experiment in street- washing I had the gullies and sewers within the city carefully examined from time to time, when they were found to be not only as clean as they had previously been, but, if anything, cleaner ; and, indeed, I think that if the surfaces of the city pavements were cleansed by water alone, both gullies and sewers would be cleaner than at the present time, for, as before stated, much dust or dirt is now swept into them in such condition that the usual current does not readily move it, whereas, if the streets were daily washed, nothing would go into the sewers excepting that which found its way there by reason of its fluidity." Where the streets are paved as in the city, no reasonable objection could be raided to the adoption of such a system ; with macadamized roads, however, it might be different. Under any circumstances, the hose-pipe would have the effect of thoroughly cleansing the streets of all their impuri- ties, no matter what might be the nature of the pavement or the condition of its surface ; and it would be equally applicable and effective in all weathers, frost excepted. Under the present arrangements, and during dry weather, it is at times quite impossible to remove the dust and dung, etc., which accumulate in the strepts, and which, as I have already stated, under certain conditions are the cause of offensive smells. To in part mitigate this nuisance, I have caused the streets to be swept during the early hours of the morning ; and although this has generally speaking been, to some extent, successful, it cannot at all times be performed with good effect, for in certain seasons the ground is during the early morning so damp from heavy dews that sweeping alone fails to remove the dry dust and other offensive matter from the surface of the streets, into which they have been firmly trodden. For the past two summers I have had the principal thoroughfares washed twice a week, and the result has proved so beneficial that during the excessively hot weather of last summer I had 224 STREET OPENING. not one single complaint. Such a system of street cleansing would be the most successful method applicable, as cleansing by water produces a perfect state of cleanliness, by the removal of all decomposing matter. Receptacles for Street Mud. Failing this scheme, the only other method I can suggest is by making provision in the streets for the reception of the sweepings during the wet weather, which is quite practicable. The quantity of slop or mud swept from the macadamized roads on a wet day averages in this district from four to five loads per mile. In certain streets, of course, the quantity to be removed would be greatly in excess of this ; but these would be the exception. All that would be required, therefore, would be to construct in each street a receptacle of sufficient capacity to contain the slop swept from its surface, and as the quantity to be allowed for is small compared with the entire length of the street, this might be effected by a very simple arrangement namely, the construction of a suffi- cient number of troughs in each street, at convenient distances apart, placed alongside the curb, and underneath the channel way into which the mud on the streets would be at once swept, and whence it could afterwards be carted. The great advantage of this would be that in sloppy weather the whole of the mud and dirt swept from the surface of the streets would be immediately removed out of sight. The receptacles might be made fixed or movable as required, and constructed so as to present no unsightly appearance ; in fact, they would in appearance exactly resemble a length- ened street gully, except that provision would be made to prevent the entrance of storm-waters. In a thoroughfare like Park Lane, for instance, which on a wet day yields about thirty loads of slop, thirty of these recepta- cles, placed at suitable intervals, each seven feet long by two feet wide and two feet deep, would be ample for the reception of the accumulated slop of the entire length of roadway. The contents would be removed in carts at leisure, either during the day or at night. Under existing arrangements the time occupied in filling a cart varies from twenty minutes to half an hour according to circumstances. By the proposed arrangement a cart could easily be filled in half the shortest period now required. Sweeping Machines. Failing both of these suggestions the only other alternative is to increase the number of horse-sweeping machines, and make it binding under heavy fines upon the contractor to remove the whole of the mud as quickly as it is swept from the surface of the streets. A man with a broom will sweep about 3,000 square yards a day ; a man and horse with rotary sweeping-machine will sweep an area ten times as great namely, say 30,000 yards. In addition to and in connection with either of these systems the erection of " orderly bins " along the sides of the principal streets, to collect the horse-dung and other matter which accumulates during the day, would be of much use and greatly assist the work of cleansing. Practice in Paris. In Paris the sweepings of the streets are not removed in carts as is the system here. There the London " slop" cart is unknown, the refuse and mud is not permitted to remain on the surface of the streets, but is, with the aid of water, swept directly into specially constructed sewers. Conclusions. The conclusions resulting from the foregoing may be recapitulated as follows : First. The work of repairing and maintaining the parish roads would be more economically and efficiently performed by having ample accomrao- STREET OPENING. 225 dation for the storage of road material; by the employment of able-bodied laborers; and by discontinuing the use of macadam in all leading thorough- fares. Second. Cleansing would be more rapidly effected by such methods as the employment of hydrants, with receptacles for sweeping at the street sides; employing more horse sweeping-machines; obliging contractors to remove mud as swept up; increasing the number of parish horses and carts, etc. , and discontinuing macadam in leading thoroughfares. Maintenance in Chelsea* The following items are from the annual report of Mr. George R. Strachan, Surveyor to the Parish of Chelsea, London. Complaint is made of an insufficient number of street basins, and that the gutter stones, from not being laid on concrete, have settled under heavy loads, so as to form depressions which hold the water. He states the axiom, that "a street on which water gathers is a dirty street, and a dirty street is an expensive street." The use of flints on macadam roads is condemned as being " dusty in summer and dirty in winter" under heavy traffic. Good granite is recom- mended, but not such as breaks into sharp, razor-shaped pieces. Large stones are a positive evil, and it requires much care to insure that the stones do not exceed two inches in the largest dimension. The paragraph on the wastefulness of macadam roads for streets carrying heavy traffic is worth quoting entire: Cost of Maintenance. Broken granite at its best is very wasteful as a material for maintaining carriageways where heavy traffic exists. A cubic yard of Guernsey granite costs the Vestry I2S. bd. on the wharf this year. The cartage of it to the carriageway, spreading, rolling, and consolidating it costs gs. bd. more, or a total of 22s. on the finished carriageway. It is there ground to dust in dry weather and to mud in wet weather, and becomes, taking an average of all weathers and of the traffic weights in Chelsea, four cubic yards of slop or mud. These cost IDS. $d. for sweeping to one side of the carriageway, 6s. for carting to the wharf, and then 43. $d for their disposal. From first to last the cubic yard of Guernsey granite has cost 2 2S. f)d. In roads like King's Road one year's wear is the utmost that is obtained from it. The average life in the home district is only four years. The temporary use of the material at the large cost named brings vividly to the mind the unscientific and wasteful character of macadam roads in heavy traffic, and points to the necessity of using a better and different class of material for carriageways in main thoroughfares. Steam Rollers. As to the value of steam road-rollers the report states that, after a contest in the courts, the right to use them has been maintained, the gas company having sought to restrain them on account of damage to pipes. One of twelve tons and one of ten tons are now in use, at a cost for each of los. 6d. per day, including driver, fuel, oil, etc. By the use of one 300 square yards *xvii, 116. 226 STREET OPENING. can be finished per day, with a great saving to tradesmen on a street by the shortening of time occupied in repairs. Repairs by simply throwing stone loosely on the surface and depending on traffic to pack them is considered a cruelty to horses and an inconvenience to the public. Two gas-mains have been cracked by the rollers, but the insignificant cost of their repair bears no comparison to the saving by the use of the rollers. Cost of Repairing. The following statement is given of the actual cost of repairing Harrow Road, the area repaired being 9,522 square yards: s. d. Estimated cost 390 o 6 ACTUAL COST. 477 scores 35 15 6 403 tons granite 211 14 i 216 yards hogging 52 4 o I 3>5 gallons water 10 ij 76 } days' horse hire 34 6 3 Labor 48 4 10 Roller. Maintenance (i per cent, on .375) 3 15 o 3,500 gallons water 2 75^ Half ton coal 9 3 } 125 bundles wood 4 4 *^ Six chaldrons coke 214 o 390 o i Below estimate. . o ; Cost per square yard; 9.82^. Average area rolled per day of 10 hours, 423^- square yards. Average thickness of granite, about 1.38 inches. Wood Pavements. As to wood pavements, some which have borne a traffic of 550 tons per yard in width during sixteen hours per day for seven years are good for some time to come. These pavements wear most at the sides of the road where the water lies on its way to street-basins; the surface also wears uneven in the older portions. Hard wood has not proved satisfactorj ; when one block is defective it wears more rapidly than adjacent ones, and cup- shaped depressions are formed, instead of saucer-shaped as in the softer woods. Asphalt Pavements. Of asphalt pavements Mr. Strachan says: " I venture to state that there is not a pavement in use so economi- cal, healthy and clean, and with so many advantages as asphalt. Its one disadvantage of slipperiness does not, in my opinion, outweigh its advantages." STREET OPENING. 227 The various carriageways now paved with it are in better con- dition than when first completed. " They make no mud, and are always wholesome. A heavy rain washes them clean, and an extra watering attains the same end." The footways paved with asphalt mastic one inch thick are spoken of in the highest terms, although compressed asphalt is un- doubtedly most durable. The trouble from cracks in the latter and methods of overcom- ing were treated of in previous articles. Flag-stone footways allow water to percolate through the joints into cellars unless they are laid on concrete. Cleaning. The main streets are swept daily, others three times and twice a week according to their importance. Six gangs of men are engaged in this work, and are assisted by four sweeping-machines and three scrap- ing machines whenever practicable. The wood pavement is washed during dry weather, and the slop occasioned thereby is removed as quickly as the present system allows of. Street orderly men are regularly employed on the wood pavement to remove the horse-manure and the refuse. During the year 19,695 cubic yards of slop and street sweepings have been swept from the streets, and have been carted to the wharf at 2s. 3^. per load. These were shot into barges, and removed at is. %d. per load. Removal of Refuse. By contract, the carts are to call at every house once a week at least, and the men are to ask for the dust. The system fol- lowed when an application is made for the removal of dust is for an inquiry to be made as to why it was necessary. If the contractor is at fault, he is informed of the fact; if the servants have refused to allow the men to take away the dust when they called, their master is informed of that fact; and if the householder has been averse to having it removed weekly, he is urged, on the ground of health, to allow it to be taken each time the men call; and by these means it is endeavored to secure a regular and weekly removal of all the household refuse. The collecting contractor is instructed not to collect trade refuse as dust, and a strict watch is kept on what he delivers to the wharves. The public grumbles at the local authority for its neglect in the removal of dust, yet they put out of the reach of the local authority the only means of doing the work well. The custom of tips is the curse of local effort. It demoralizes the men, it causes them to act dishonestly in remov- ing rubbish that ought not to be otherwise disposed of, and it inflicts a great hardship on the poor. Street Watering. For street-watering the price paid for water is gd. per 1,000 gallons, and the cost has been ^"65 igs. lod. per mile watered. Street Opening by Gas and Water Companies. Street openings by gas and water companies cause damage to the roads and are an annoyance to the public. They may be necessary for the business of the companies as at present conducted, but they are an injury to the roads. I am con- vinced that sooner or later the local authorities of the metropolis will have to take united action for their own protection against the powers and cus- toms of these bodies. I have already referred to the steam-roller case where the law has subordinated the rights of the public in the repair of the streets to the rights of these commercial undertakings. At the close of the 228 STREET OPENING. year the law has been held to make the public liable for personal injury under the following circumstances: A water company placed an iron box in a York stone footway under their statutory powers. In time the stone wore below the level of the iron box and an unfortunate pedestrian tripped up over.it and sustained serious injury. He brought an action for compen- sation, and it was held that the local authority was liable. In this case the local authority cannot successfully refuse to have the iron boxes fixed in their pavements, and yet they are required to keep the pavements up to the boxes. If the boxes were not there the pavement would wear equally and no injury would be caused. This is a serious liability. I have not objected to the Chelsea Water- Works Company inserting such works and apparatus as they deem necessary in the streets, but if these liabilities are to be thrown upon the Vestry, it will be my duty to draw the attention of the Vestry to the question. It is no light matter to engage in lawsuits with these companies, when one of them can spend ,100,000 in law, and then pay 10 per cent, to its shareholders out of the annual revenue. MAINTAINING MACADAM ROADS IN LIVERPOOL.* On the subject of pavement in cities of the Continent of Europe and Great Britain, Mr. Clement Dunscombe, City Engineer of Liver- pool, writes : In the area referred to there are innumerable descriptions of pavements, some good and some bad, and in many of the large cities and towns the same remark applies. Some of these cities and towns are, as a whole, extremely well paved, but in no city or town is the pavement laid down so thoroughly well constructed, so durable, and so sanitary as in Liverpool ; and what, to some, may appear extravagant in the methods here pursued can be proved by demonstration to be the most economical over a series of years. The cost of the maintenance of the carriageway pavements and footways in London is nominal, and a large proportion of the amount ex- pended under this head is due to the retention of macadam roads, which are maintained as such owing to the exigencies due to local circumstances. The low cost of maintenance is obtained by laying down the pavements in the best possible manner, and making all repairs at once when needed, so that the pavements are always in a superior condition, and the cost of main- tenance is reduced thereby to a minimum. THE CARE OF PAVEMENTS.f Professor J. S. Newberry also gives some good advice in a paper on " The Street Pavements of New York," published in the School of Mines Quarterly for July, in which he clearly points out what is so little appreciated here, that even the best pavements require constant and prompt attention, saying : In a recent visit to Washington I found some of the streets in a bad condition. Even on Fourteenth Street, in front of the Treasury building, the asphalt pavement is full of holes, and the condition of this great thoroughfare has led to an opinion which I found quite prevalent, that asphalt was only adapted to streets where traffic was not great and the *xv, 485. f xx, 155. STREET OPENING. 229 vehicles were light. This is a mistake, however. There is no street in America, or elsewhere in the world, that has as much traffic as Cheapside, London, and among the vehicles which pass through it are omnibuses, loaded with passengers inside and on top, carts of all descriptions, and, heaviest of all, the trucks of the great brewers, with their enormous horses and tons of ale and porter. And yet Cheapside is paved with asphalt, and is as smooth as a house-floor. The secret of its perfection is the thorough manner in which the pavement is laid and the incessant care given to it. In nothing is the axiom truer than in the asphalt pavements, "that a stitch in time saves nine." The material has little hardness, and if from irregular settling of the road-bed or local violence a break occurs, the passing wheels rapidly shear off the sides of the hole, and it soon assumes formidable dimensions. In London this is prevented by constant watchfulness ; per- sons are employed to traverse the street with a light repairing outfit, and wherever a defect is observed, this is patched at once, and so effectually that the spot cannot be distinguished. The contractors who lay the pave- ments agree to keep them in order for fifteen years, at a price which does not average more than a few cents a square yard. Our people seem to think that no pavement is a good one unless when once laid it will for ever take care of itself ; but there is no such pavement. Even our rough stone roadways would pay excellent interest on the expen- diture necessary for constant inspection and repairs promptly made when needed. Such articles as these, and others like that of Clemens Herschel on " The Science of Road Making," should go far to direct this awakened public interest into intelligent and effective lines of action and insure, for instance, that the $3,000,000 recently appropriated for improving the pavements of New York City shall be expended to the best possible advantage. Such an object-lesson to the rest of the country as a well-paved metropolis could not fail to be of incalculable value, and it is earnestly to be hoped that the oppor- tunity now presented to teach this lesson may not be lost through the ignorance or indifference of any one in authority. We do not believe that it will be, and we find our strongest reason for this belief in what certainly seems to be an aroused and enlightened public sentiment in favor of good pavement and plenty of it. CLEANING PAVEMENTS IN THE CITY OF LONDON.* From the last report of Mr. William Haywood, Engineer of the city, which, it must be remembered, is a small portion only of the great metropolis, we gather some interesting items as to the pres- ent ideas of the English engineers on pavements. The carriageways on portions of three streets have been laid with Val de Travers compressed asphalt. Another street which had been paved with Henson's wood pavement was also relaid in the same asphalt, the wood having become in bad condition. * xvi, 347, 230 STREET OPENING. Four streets had been laid with Limmer compressed asphalt. Two others which had been paved with wood, and were in bad condition, were also relaid with Limmer asphalt. Wood pavement was renewed in three streets and parts of streets. Granite was used in two streets, but the " relaying of streets with granite diminishes yearly, wood and asphalt (principally the latter) gradually being substituted for granite in the city." For footways Val de Travers compressed asphalt was used in four streets, Limmer asphalt in six streets, and stone in five streets. The whole of the carriageways are swept once daily, the main thoroughfares, in wet weather, swept a second time during the day. In addition to the general cleansing of the whole surface, the street orderly system was in operation on the carriageways of all the main thoroughfares, about 150 boys being employed for that pur- pose. The great advantage of this street orderly system is most apparent in wet weather, the thoroughfares where they are employed being at such times in a much greater state of cleanliness than they are elsewhere. The work of cleansing the main thoroughfares often begins as early as two, three or four o'clock in the morning. The street orderlies then take up the work at about 7.30 A. M., and cease work at about 4.30 p. M.; late in the evening, when the weather permits, or the condition of the surface renders it necessary, the carriage- way pavements are washed. The cleansing ot the carriageways in the main streets is, therefore, almost continuously going on. The quantity of water used during the year 1886 for washing the streets and courts was about 2,247,790 gallons. The number of nights when the water was used was 88. The footivay pavements are swept by the Commission whenever it is necessary, and in wet weather those in the main thoroughfares are cleansed with squeegees during the day. It is a statutory obli- gation on the part of the occupiers of property to keep the foot- ways clean in front of their premises, an obligation but little attended to by the inhabitants in any part of the city. The courts and alleys inhabited by the poorer classes were washed with jet and hose twice a week between May and the end of October. A very few places are washed nightly throughout the year for special reasons. The street orderlies and scavengers have for some years been occupied at times in strewing sand and gravel upon the streets which have the greatest traffic. The average quantity so strewn during the last three years has been about 650 cubic yards, and the ten- STREET OPENING. 231 dency is for it to increase. The extra work in removing this quan- tity of material when converted into mud is, in some states of the weather, very great indeed, especially from wood pavements. This circumstance also adds to the difficulty of keeping the streets clean, as^well as to the cost of cleansing. The engineer complains of the trouble arising from the collec- tion of house refuse, owing to the abuse of the privilege allowed of placing their dust and refuse on the footways in receptacles of insufficient size, or with none at all. CHAPTER VII. NOTES. EXPERIENCE WITH ASPHALT AND OTHER PAVEMENTS IN THE CITY OF LONDON.* Continuing our account of experience in England, we come next to a series of reports on the pavements in the " City of London ' proper, where the travel is probably more per unit of width than in any other city in the world. We are indebted for the information to William Haywood, Esq., Engineer and Surveyor to the Commission- ers of Sewers of the city, and the reports date from 1886 back to 1853. The first wood pavement seems to have been laid there in 1839- One laid in 1842 up to 1853 had had two renewals, making the average total cost (including ^d. per annum for repairs) to be is. n^/. per year. Granite for the same time cost g^d. total per year. To the cost above for wood should be added about \\d. for sanding to prevent slipperiness. The duration of granite in this statement is taken at twenty-five years. The practice is to lay the new granite in the streets carrying the heaviest traffic, then after a certain amount of wear to remove it, redress it as required, and lay in second-class streets, and, finally, after a second removal, it is placed in streets with least traffic on them. The dressings are used in macadam, and finally the worn-out stones take the same course. Statistics are given of a granite pavement on London Bridge* where it lasted twelve years under this enormous traffic before renewal. The stones, originally 9 inches deep and 6 wide, had worn down an average of 2 inches. The cost per year was ^\d. for maintenance and is. io|^/. for laying, or 2s. ^d per year. In the Poultry, another very busy street, the wear in six years was i inches. From a table given we learn that the first squared granite blocks were laid down in 1828 and were not renewed for from sixteen to twenty-five years. These were 6 inches square by 9 inches deep. The 3 and 4 inch granite cubes were introduced in 1844, and bore the very heavy traffic of Cheapside and similar streets for seven to nine years before relaying, many of the blocks being still fit for use. * xvii, 150. NOTES. 233 Up to 1852, of 21 wood pavements, the time down before renewal ran from twenty-three months up to eight and one-half years, the larger number lasting less than four years. There are about 51 miles of public ways in the "city," con- taining 441,250 square yards of carriageway and over 300,000 square yards footway. The next report in the series dates 1870, and contains an account of a pavement called " McDonnell's Patent Adamantean" composed of broken stones not over 3 inches in diameter imbedded in asphalt, and laid in blocks 18x12 inches and 6 inches deep, with j-inch joints filled with asphalt. An interesting case is reported where suit was brought by the owner of a building against the Commissioners for damages caused by raising the grade of the street so that he had to use steps to go down to his property. The case was decided on final appeal in favor of the Commissioners, on the ground that it was done in the interest of public traffic. The report states that since 1867 the Commission has removed all dust, ashes and trade refuse. The street "orderly" system, and erection of iron bins along the sidewalks for the reception of the manure collected, was begun at that time and has been continued to the present. The average amount of material removed per week, not includ- ing snow, was 97 2 J loads. The usual requirements as to maintenance are as follows : In the case of asphalt pavements, the contractors for the pavement when new agree to maintain it in good repair for two years without cost to the city, and after this for fifteen years more at a price per square yard per annum named at the time of bidding and based on the total area paved. The pavement to be in good condition (to the satisfaction of the engineer) at the end of seventeen years, and to weigh at that time not less than a given amount per square yard. For wood pavements the agreement is entirely similar except the provision as to weight. The report of 1871 mentions the first laying of granite blocks with wide joints, and filling with small pebbles, and a composition of pitch and creosote oil poured hot. Observations made that year show that there were fewer falls of horses from slipping on pavements of compressed asphalt than on the ordinary granite pavement. Experiments were made that year on melting snow from the streets by steam and gas. On account of disturbance of the streets for laying pipes of various kinds subways are pointed out as the only remedy. They were then in use in four streets. 234 NOTES. It is interesting to notice in all the reports thus far, frequent mention of street widenings, which have done so much towards relieving the street traffic during recent years. In 1872 mention is made of the failure of a pavement consisting of blocks of compressed asphalt laid on concrete and grouted with bitumen. These were 13x6^ inches and 2^ inches deep. Much consideration was given to asphalt pavements this year. The first specimen of the regular Nicholson wood pavement was laid also, and as asphalt was considered unsuitable for grades steeper than one in sixty, wood is suggested as a possible substitute in such localities, taking the place of the asphalt. Complaint is still made of the disturbance of the streets for laying of pipes. In 1873, the Adamantean pavement laid three years before, is reported upon. It showed serious wear at the end of one year, at the end of eighteen months received extensive repairs, and in two years was so bad that further payments upon it were withheld. A pavement of Trinidad bitumen, broken stone, chalk, etc., laid hot, was proven to be a failure; also, one consisting of a mixture of certain oils, caustic lime, pitch, sawdust, etc. A pavement of compressed asphalt from Seyssel rock (Societe* Francaise des Asphalte), also from Montrotier asphalt, proved enduring. Experiments also showed that such pavements would not aid in spreading fire. Patent wood pavements of various kinds began to be experi- mented with. A footway of Portland cement laid under pressure was also put down. Seven street-sweeping machines are reported in use. The washing down of streets paved with asphalt begun in 1866, and was still under trial as an experiment. It would seem from a statement made here that the city retains full control of the subways under the streets. More streets were torn up for pipes of the Gas Company and Hydraulic Pressure Company. Conflicts of authority are noted between the Commission and Metropolitan Board of Works as to control of certain streets, etc. A separate report was made this year on asphalt pavements. The tests of thickness by pieces cut out, weighed for compressed asphalt from about i6| to 22 pounds per square foot; the original thickness being about 2 to 2\ inches and reduced thickness T \ to } of an inch less. It would seem to indicate less care in compression in some cases than in others. NOTES. 235 In 1874 a patent "asphalt " pavement, consisting of tar, cement, sand, and sawdust, laid 2^ inches thick, while hot, under a pressure of 112 pounds per square inch, on concrete foundation, was tried, and taken up in two months. Another, called a metallic asphalt, consisting of blocks 2x2 feet and 4 inches thick, made up of manufactured "asphalt" and burnt ballast, also failed in the same time. This year the " Court of Common Council" resolved, " That in their opinion tramways in the 'City' of London will occasion greater inconvenience to the general public and to the traffic within the city than they will conduce to the convenience of the public." Comparative Advantages of Wood and Asphalt. A special report made this year on asphalt and wood pavements gives conclusions as follows: Asphalt is less noisy than granite and wood less than asphalt. Asphalt needs close attention to repairs or is speedily knocked to pieces. Wood is in time unequally worn, and causes more jolting and noise than when new; disturbing those inside of carriages, however, the most. Large blocks with wide joints wear more unequally than small blocks with close joints. Asphalt is smoother, cleaner, and drier. Water remains longer on wood and dirt remains in the joints. The smell mentioned in connection with wood has caused no complaints, and, on the contrary, people living on line of streets paved with it are anxious to have it continued. Asphalt is most pleasing to the eye, and, on the whole, most pleas- ant to travel upon. Both should be kept perfectly clean, but this is most difficult with wood. Washing is the best method for all pavements. This makes asphalt slippery, but does not affect wood. One can be laid about as fast as the other. In good weather 125 to 129 yards laid per day. Asphalt is easily repaired and wood less so, and not so permanently. As to slipperiness, it was found in Paris that i horse in 1,308 slipped on granite, and one in 1,409 on asphalt. An extended series of obser- vations for fifty days in London, with weather mostly dry and cold, the asphalt sanded, when wet, gave one fall for each horse traveling 191 miles on asphalt and 330 on wood. On wet days this became respectively 192 and 432 miles. The complete falls were in the ratio of about i wood to 4 asphalt. The wood gives more chance to the horse to save himself, while a small quantity of mud makes asphalt very slippery. It is more difficult for the same reason for a horse to get up from the latter. Wood, on the contrary, seems to be more slippery when frost and snow prevail. It is not so safe at ordinary times to drive fast on asphalt as on wood ; and a horse can be stopped quicker on the latter, except in frost. 236 NOTES. Compressed asphalt in all cases proved more durable than other asphalts. The opinion is expressed that no asphalt will last more than four to six years without much repairs, and that their entire surface must be renewed in from six to ten years. The cost reported on eight compressed asphalts at the date of the report for whole cost and maintenance for the seventeen-year term was, per year, from is. A^d. to 2s. 4^/., the average being is. 8^/. At the same date wood pavements were reported, under a heavy traffic, as lasting nine to eleven and one-quarter years, the total sur- face having been relaid at least once, and additional blocks inserted from time to time, the mean total cost per annum being 2s. *j\d. for those under heaviest traffic and 2s. ^\d. for lighter traffic. In 1875 Ludgate Circus was completed, giving a diameter of 1 60 feet, and greatly relieving the consequent traffic at that point. A large number of patent wood pavements laid down for experi- ment, replacing granite blocks. Cleansing of the footways begun by the Commission in 1872 was continued, and a method of sprinkling streets by means of perfo- rated pipes laid along the curbs put in operation as an experiment. The slipperiness of asphalt had become a subject of complaint, and sand recommended as a remedy, sparingly used. In 1876 the granite sets with "asphalt " joints, laid three years before, were found to be in very bad condition, as it was impracti- cable to remove blocks for repairs without considerable expense, the smallest repair requiring a boiler and special heating apparatus. The pavement was a noisy one also. The apparatus for removing snow by melting was used, and the cost of melting a cubic yard found to be nj^., 192 feet of gas melt- ing one yard. Salt was then used, and then forced towards the gul- lies by hand labor. This year another patent apparatus for washing streets from pipes along the centre was put in place for trial. A number of new " resting-places," or refuges for pedestrians in crossing public streets, were constructed. This very desirable improvement is worthy of imitation in many of our crowded cities. In 1887 another of the patent pavements, called " Barnetfs iron asphalt" proved a failure, and the company threw up its con- tracts for maintenance. The compressed asphalt seemed steadily growing in favor, and also certain styles of wood. This year a pavement of blocks composed of clay highly compressed and hard-burned was laid. The blocks were 3^x8 inches and 6 NOTES. 237 inches deep, weighing 12 pounds. These were laid on "ordinary ballast," with J-inch joints filled with ballast. The removal of granite block pavements continued. The use of salt on the streets for removing snow (" coupled with quick and careful sweeping so soon as the salt has done its work ") was continued as the most effective means. In 1879 Davisoris patent iron and asphalt pavement was laid, consisting of iron frames with projecting iron studs, set in mastic asphalt on a concrete foundation. A similar one with lead disks proved a failure in three months. Up to this date thirteen kinds of asphalt pavements and eleven of wood had been laid, so that nearly every portion of the great arterial thoroughfares were paved with one of these. In 1880 the iron and asphalt pavement and one of the mastic asphalts proved failures, also a " noiseless granite " pavement laid on felt, etc. This year was laid a sidewalk pavement consisting of slabs made of pulverized granite sifted to the fineness of sand, mixed with Portland cement and water, and after setting, dipped in a sili- cate of soda. A nuisance of steam discharged into sewers, and escaping into streets, etc., was abated by the Commission forcing the construction of a special sewer by the offenders. In 1880 another subway for pipes, etc., was constructed by parties owning property on each side of a newly-opened street. A specimen of the so-called granolithic pavement, made of crushed granite and lime or cement, was laid. Wood and asphalt had now almost entirely replaced granite in the main thoroughfares and many of the minor streets, asphalt predominating. Three more " resting- places " were introduced. The construction of subways was again forcibly urged as the only means by which to prevent tearing up of the streets. In 1882 the washing of streets by a hose and jets having been in use two years was reported upon favorably. In the same year a special report gives the annual cost of maintenance only of various pavements as follows : The average for 16 of Val de Travers compressed asphalt was is. per yard ; of 7 Limmer compressed asphalt, <)\d.\ of 5 Societe Franoais des Asphalte's compressed asphalt, \\d.\ of 9 improved wood, i2j oz. y 2 oz. Flint and similar stones. 1 " 3/ " Limestone and similar stones 6 i ** One-half of the total quantity to be of the maximum weight, one-eighth of the minimum weight, the remainder to be composed of stones varying between these. There is no doubt that the hard and tough rocks should be broken into smaller fragments than those that are softer. For ordinary country roads the cleaner and more even the size of the stone the better, as there is always in the road plenty of loose material for bedding the new stones. The author's experience leads him to give as his opinion that for the repair of a main road in rural districts, where granite or similar hard material has not been long used, the size to pass through a two and one-half inch gauge is not too large. If the fragments are smaller than this they are squeezed into and lost in the softer material, their size not being large enough to give sufficient bearing surface to withstand the weight of the wheels of heavy vehicles. After granite has been used for some time and the road has become fairly coated with it, so as to give a good resisting surface, a size to pass through a one and three-quarter inch gauge is sufficiently large to fill up the depressions. If a smaller size than this is used it will not stand the crushing of the wheels, and soon becomes dust. All stone should, when practicable, be carted and placed in heaps at the sides of the road during the summer, when the roads are hard. The material is then ready as wanted, and there is less wear and tear on the road by carting than if it be done in winter. All stones harden by ex- posure to the weather. Stones that have been lying during the summer in heaps will wear longer than those brought directly from the quarry. As far as practicable materials for repairs should be placed on the roads in the early part of winter to allow of its being thoroughly bedded and in- corporated with the old material. As a matter of experience it has been found that stone put on in the early spring, although apparently well bedded and set, will work out again much sooner than that put on in November and December. If it is necessary, as will sometimes be the case, to place the stones on the road at other times than in winter in order to fill up depressions or to prevent the formation of ruts, the surface should be loosened with the pick, the stone evenly spread and covered with road- scrapings. If this be carefully done the place so repaired will soon be- come as firm and as level as the rest of the road. For repairs of this kind only the smallest kind of material should be used. Many surveyors keep a supply of granite chips purposely for the repair of hollows and defective places in summer time. Cost of Repairs. It may be taken as a fair estimate for the main roads of this country, excluding the strictly urban portions, that a mile of road will require 40 tons of granite to repair it, and that one man can keep in order four miles of road. Putting the granite at $2.50 per ton, and the wages $1.25 a day, this, with an allowance for carting, extra labor, and in- ROADS. 259 cidental expenses, would give $175 a year as the cost per mile. After a road has been thoroughly well coated with granite, the quantity of material required will decrease considerably. On the other hand, roads which have previously been repaired with soft and inferior material will require a larger quantity of material and more labor. THE ADMINISTRATION OF COMMON ROADS IN FRANCE.* Under the title " Local Government and County Councils in France," M. Waddington, the French Ambassador at London, has some very interesting notes on the administration of the public roads of France. France is divided into departments, each department into arrondissements, each arrondissement into cantons, and the admin- istration unit is the canton, which may be composed of several rural parishes, a town and adjacent parishes, or a portion of a city. An arrondissement consists of five or six cantons, while the departments, of which there are 86 in France, are generally composed of 35 or 40 cantons, but vary from a minimum of 17 to a maximum of 62, and from the Department of the Seine, with nearly 3,000,000 inhabitants, to that of Belfort with 80,000. M. Waddington compares these departments to the English county, and uses the word county in speaking of them. Throughout France the roads are divided into five classes as follows : 1. Routes Nationales. These great highways, which preceded the railroads, and parallel to which the railroads were generally located, lead from Paris towards the frontiers, join large towns like Lyons and Bordeaux, or connect the different fortified posts along the frontier. At the beginning of the century they were the main arteries of traffic through France and the only roads kept in good repair. They are now much less used, but are kept in good order and are entirely maintained by the State under the direction of the Ingenieurs des Fonts et Chaussees. 2. Routes Departmentales. These connect the different towns of a department with each other and with those in a neighboring department. They are not quite as broad as the " Routes Nationales," but have more traffic than any other class of roads and are kept in admirable order entirely out of the funds of the department, or "county rates," and are under the direct management of the " conseil general" an elective council of one member from each canton. 3. Chemins de Grande Communication. These are almost equivalent to those last mentioned and the two are now often completely amalga- mated. The "Routes Departmentales" were, while maintained out of county rates, managed by State engineers, and the " Chemins" were con- structed and maintained partly by county fines and partly by contributions of the different parishes, and managed by county officials. 4. Chemins d 1 Inttret Common. These are country roads for local circulation of less width and less solid construction than the preceding, and *xviii, 135. 260 ROADS. are mainly maintained by parochial contributions, with the aid of variable annual grants from the county. 5. Chemins Vicinaux Ordinatres. Purely parochial roads, connect- ing the villages or hamlets of the parish. They are maintained out of the resources of the " commune," and under the supervision of the Mayors of the commune, but county officials lend their assistance or advice when requested, and make plans for their construction, to which both the State and county contribute aid in the case of the poorer parishes after the commune has furnished proof that it is able to maintain the road when once constructed. The construction and maintenance of these roads, other than the first mentioned, is managed by the ' conseils generaux," and though in some instances the service is managed by engineers of the " Fonts et Chaussees," who in that case receive an extra pay from the department, they are, in general, in charge of " agents voyers." An " agent voyer en chef " for the department, " agents voyers d'arrondissement," and in each canton one or two "agents voyers cantonaux." The latter have charge of the " canton - niers," who are permanently employed, with a month's holiday in harvest time, and execute the current repairs and maintenance, aided by workmen temporarily employed in case of emergency. These " agents voyers " now form a very considerable body of highly- trained men, supporting a monthly review which deals with questions of interest to them. A special budget for the roads of the department is prepared by the "agent voyer en chef "and laid before the"conseil general "each year. It is divided into two sections, the first relating to maintenance and the second dealing with the reconstruction and improvement of old roads or the construction of new roads. The resources are (i) " Prestations en naturi," (2) " Subventions indus- trielles," and (3) Contributions from the county rates. Every taxpayer is bound to furnish for the maintenance of the roads in his parish and vicinity three days' labor, called " journees de prestation," not only for himself and all laborers permanently in his employment, but of all horses, donkeys^ mules, draught oxen, and carts in his possession, or commute such services at a rate established every year ; or the prestations may be converted into piece work. The '* subventions industrielles " are levied on the principle that certain industries and manufactures, such as beet-sugar works, distilleries, etc., which cart heavy loads, cause an abnormal wear of the roads, the repairing of which cannot be fairly charged to the general taxpayers. The amount of this subvention, which must always be spent on certain specified roads, is arranged with the " agents voyers" under the sanction of the " conseil general," or, if .the parties cannot agree, the question is referred to the administrative tribunal of the department, with whom the final decision lies. The old corve, or warning peasants out to work on the roads once or twice a year, with the consequence that the roads were never in good order, has long been abolished in France, and the system of continuous mainte- nance substitutedjias given that country the best roads of any except Italy, where a system of continuous maintenance under the charge of permanent officers is also in use. The system in this country does not require either description or characterization. ROADS. 261 ROADS AND RO4.D-MAKING.* The progress of civilization has everywhere been marked by good roads. It may even be said to be largely due to them. Ancient Rome was not only famous for its own roads, but it carried the art of road-making into all its conquered provinces. As its civilization disappeared in the degen- eracy of the Dark Ages, good roads ceased to exist, and they only reap- peared when modern nations began to emerge from the Middle Ages. It is often said that the test of civilization in any country is the consumption of iron ; but this is true only because railroads are the chief consumers of iron, and they are but one form of roadway. It is an undeniable fact, that while the United States has the finest railway system in the world the most perfectly adapted to the work it has to do, and the cheapest in charges for transportation yet its roads and its city streets are far inferior to those of France, England, Germany, Austria and Italy. Doubtless, the admirable character of its railways is itself the cause of its bad roads and streets, for the railways serve their purpose so well that there is less apparent need of good carriage roads. All the other countries above named had reached a high degree of civilization before the advent of railways, about fifty years ago, whereas, about three-fourths of the present area of the United States have been settled and populated during the railway era. The rapid advance in wealth and population of the principal countries of Europe during the latter part of the eighteenth and early part of the nineteenth century would have been impossible with- out a corresponding and simultaneous improvement in the quality of their roads. The still more rapid advance of America during this century has been accomplished chiefly through the instrumentality of railways, and these have so thoroughly intersected the country in every direction, bring- ing the merchant and manufacturer at one end, and the farmer and miner at the other, into such close communication, that the necessity for good roads has been overlooked. The opinion is now gaining ground, however, that notwithstanding the excellent and cheap service of the railways, there is a great loss in the unnecessary cost of transportation in hauling merchan- dise through the mud to reach the railroad, and again over rough cobble- stones when it leaves the cars at its destination. And independent of the commercial aspect of the question, there is still to be considered the com- fort and convenience of those who use roads and streets for pleasure riding and driving, and to whom good road surfaces are absolutely necessary. During the last few years there has been a constant increase in the atten- tion and thought devoted to the question of roads both without and within cities, and the object of this article is to give briefly such information as to the history and present condition of the art of road-making as may be useful in this discussion. Roman Roads. The much-quoted Roman roads were, in reality, far inferior to the best roads of modern Europe, and were much more costly. Hence they may be dismissed in a few words. They were stone pavements with a very thick concrete foundation ; or, as described by another writer, they were " masonry walls laid on their sides." The most famous of them was the Appian Way, constructed about 313 B. c., from Rome to Capua, and *xx, 145. Abstract of a paper by Captain Francis V. Greene, in Har- per's Weekly of August 10, 1889. 262 ROADS. subsequently extended to Brundusium (Brindisi). The foundation con- sisted of one or two courses of large, flat stones, laid in lime mortar ; next came a layer of concrete made of one part of lime and three of broken stone, thoroughly mixed and consolidated by ramming ; on this was spread a thin layer of mortar, in which the stones forming the top course were bedded. These stones were of basaltic lava, about 12 or 14 inches in width, with smooth upper surfaces, but irregular sides, and when carefully jointed together they formed a large mosaic. The total thickness of the road was about three feet, and its width varied from 12 to 20 feet. On either side were raised footways, paved with stone, and at frequent intervals were stepping-stones for mounting horses. It was also marked by mile-stones, indicating the distance from the forum at Rome. This road was certainly durable, as is proved by the fact that although it had to be rebuilt by Trajan, at the end of the first century A. D., parts of it are still in existence, 2,200 years after it was first constructed ; but it was deficient in the other qualities of a good road. Horace is authority for the statement that it was " less fatiguing to people who travel slowly." Similar roads were built in Gaul, in Great Britain, during the Roman occupation, and in Thrace by the Emperor Trajan. With the decline of Rome, road-making shared the fate of the other mechanical arts, and for the time was forgotten. Good roads were unknown again in Europe until the middle of the eighteenth century. They were revived almost simultaneously in France and England, and soon afterward in the other chief countries of Europe. Macadam Roads. Among English-speaking races the perfection of modern roads is generally attributed to two Englishmen, Macadam and Telford, who rebuilt nearly all the English roads in the early part of this century. Telford was a distinguished engineer, while Macadam prided himself on being nothing but a road-maker. It is also generally believed that to Macadam is due the principle of using small angular fragments of clean stone, which, under traffic, unite into a solid mass. The distinctive feature of Telford's roads was a layer of irregular stone, from six to eight inches in size, carefully placed on the ground as a foundation for the smaller stones, technically called the road metal. The chief object of this foundation was to afford good drainage, and prevent the metal from being pushed into the ground in places where it was soft ; but Macadam always denied its utility or necessity, and engineers are still divided on this ques- tion. In regard to the size of the metal, Telford specified that the stones should be as nearly as possible uniform in size, the largest of which should pass, in its longest dimensions, through a ring two and one-half inches in diameter. Macadam preferred the test of weight, and insisted that no stone should weigh more than six ounces which is the weight of a cube of one and one-half inches of hard, compact limestone. His overseers were provided with a small pair of scales and a 6-ounce weight, in order to test larger stones. It is a fact, however, that the correct principles of modern road-build- ing are not due to either Macadam or Telford, but to a French engineer, Trtsaguet, who anticipated them in every detail by about thirty years. In a memoir prepared in 1775 Tresaguet advocated the small angular frag- ments of broken stone of Macadam, and the rough paving foundation of Telford. He built the high roads from Paris to Toulouse, and from Paris to the Spanish frontier. His views were adopted by all French engineers ROADS. 263 at the end of the last century, and it was in accordance with them that the Simplon and other great roads over the Alps, as well as the principal roads of France, were built under Napoleon. The excellence of broken stone roads caused their universal adoption in the first half of this century, and in only two particulars have any im- provements been made upon them to the present day. The first is in regard to the manner of breaking the stone. Macadam caused the stone to be broken by hand on the side of the road, the size and weight of the hammer being carefully specified. Now they are much more quickly and cheaply broken by machine. Two classes of stone-crushers have been devised for this purpose. The first, usually known as the Blake, consists essentially of a strong iron frame, near one end of which is a movable jaw of iron. By means of a toggle-joint and an eccentric this jaw is moved back and forward a slight distance from the frame. As the jaw recedes, the opening increases and the stone descends ; as it approaches the frame the stone is crushed. The second class is known as the Gates, and consists of a solid mass of iron shaped somewhat like a bell, which is supported within an iron cone. By means of an eccentric shaft a rocking and rotary motion is given to the bell, so that each point of its surface is successively brought near to and removed from the surface of the cone, which causes the stone to descend and be crushed as before. These machines are driven by steam engines and are of various sizes, capable of crushing from ten to two hun- dred tons per day. By regulating the width of opening between the jaws, or within the cone, the size to which the stone can be broken is correspond- ingly regulated ; and by the use of revolving screens with openings of various sizes, the stones of different sizes can be separated and delivered in separate piles of one-half inch, one inch, and two and one-half inches, etc. The other improvement is in the use of rollers to consolidate the road and give a smooth, uniform surface, instead of allowing this work to be slowly and painfully performed by the vehicles using it. Horse-rollers were introduced about 1834, ^d steam-rollers about 1860. There was for some time a discussion as to the relative economy and merits of the two kinds of rollers, but this has now been settled in favor of the steam-rollers. Of steam-rollers there are three principal varieties, the first known as the Ballaison, or Gellerat, designed in France, the second known as the Aveling and Porter, designed in England, and the third known as the Lindelof, designed in America. Of these the Aveling and Porter is the best for Macadam roads, and the Lindelof for rolling plastic pavements. Construction. Macadam roads are now everywhere constructed on substantially the same principles. The ground is first cleared and leveled of the prescribed width, and, if necessary, excavated to the depth of the road-covering. All roots of trees, and soft and spongy spaces not affording a firm bearing, are removed and their places filled with good gravel or broken stone. The surface is then rolled with a heavy roller in order thoroughly to compact it. If the Telford foundation is used, it is placed on the rolled earth in the form of irregular stones, from six to eight inches in size, carefully placed in position and forming a rough pavement, on which the Macadam metal is placed. If the Telford foundation is not used, the metal is placed directly on the earth, in a uniform layer not exceeding six inches in depth. This is then thoroughly compacted by rolling with a heavy roller for several hours, until the metal will not yield under the roller. Another layer of broken stone of the same depth is then placed on 264 ROADS. the first and compacted in the same manner. Finally a layer of from one to two inches in depth of very fine broken stone or gravel, not exceeding three-quarters of an inch in largest dimensions, is spread on the surface, and this in turn is compacted by rolling. The road is then ready for use. The rolling is greatly facilitated and the compactness of the road increased by thoroughly sprinkling each layer in connection with the rolling. In many cases the total thickness of the Macadam is only eight inches, instead of twelve to thirteen inches, as above described. Figure i is a section of the high-road or chaussee from Paris to Cher- bourg. Figure 2 is a section of Telford's Holyhead Road ; and Figure 3 is a section of the Western Boulevard of New York. ROADS. 265 The cost of such roads depends chiefly on two factors, the price of labor and the price of broken stone. In addition to this is the cost of cul- verts and bridges, which must be provided for any road, whatever the road surface may be. The price of broken stone varies from 70 cents to $2 per ton, depending on the character of the stone and the distance which it has to be hauled. For a road 30 feet wide and 9 inches thick, about 5,500 tons are required for each mile in length. The cost of the road surface alone is about $12,000 per mile. The cost of embankment, excavation, culverts, drains, stone gutters, etc., may carry the cost up to $70,000 per mile. These figures might even be increased in the case of roads traversing a mountainous district, where expensive embankments, cuttings in rock and earth, retaining walls, etc., would be necessary. The laying out of such roads calls for the same surveys and the same engineering skill as in the laying out of railways. The shape or cross-section to be given to the road has been the subject of much discussion in the past. Roads which are much rounded in the centre shed the water very easily, but, on the other hand, they are very un- comfortable for vehicles. There has also been much dispute as to whether the cross shape of the road should be a curve, or should consist of two straight lines meeting at the centre. It is now generally conceded that the cross section should be a curve, and that the height of the road should te about one-sixtieth of its width i. e., in roads 30 feet wide the centre should be 6 inches higher than the sides, in roads 40 feet wide it should be 8 inches, and so on in proportion to its width. The great cost of macadam roads, and the comparative lack of neces- sity for them in consequence of the enormous development of railways, has prevented their construction to any great extent in America. The National Road, which was intended to form the great highway across the Alle- ghanies from the Potomac to the Ohio, was begun under authority of Congress about sixty years ago, but it had only progressed a short distance beyond Cumberland, Md., when its construction was abandoned, in consequence of the building of railways for the same purpose. Macadamized roads have, therefore, been confined to city or suburban streets, and to a few of the older States in the East. Even the turnpikes, or toll-roads, originally built by corporations which made their profit by levying toll on each passing horse or vehicle, were macadamized only for a small portion of their width in the centre, leaving earth roads on each side. These latter were habit- ually used in summer, leaving the hard central portion, whose surface was seldom kept smooth for use during the rains and mud of winter. With the exception of these few turnpike high-roads, American roads have been built of whatever material was nearest to hand. Frequently, if not generally, they were made by simply plowing a ditch on each side and throwing the earth into a mound in the centre. An improvement on this was to spread a layer of bank gravel containing a large proportion of clay over the road; and on the New England coast, where a rocky soil and clean gravel or beach shingle were everywhere available, these materials were used, and formed a comparatively hard and durable road surface. Through the swamps and clay soils of the South, where stone and gravel were not available, the corduroy road was much used. This consisted in felling trees, stripping the branches, and placing the trunks across the road; and it was probably the most inhuman device ever suggested as a means of com- munication. In central New York, and in some parts of the West, plank 266 ROADS. roads were at one time constructed, but their lack of durability caused this system to be soon abandoned. Maintenance. The condition of a road depends not only upon the manner in which it is constructed, but upon the manner in which it is main- tained. The best of roads are being constantly worn by traffic, and if they are not quickly repaired whenever any defects appear, they are soon de- stroyed. Macadam's reputation was made not in building new roads, but in repairing old roads and keeping them always in good order. In order to accomplish this result incessant attention is necessary, so as to fill up any ruts or holes the moment they appear, and prevent them from being enlarged by travel and rain. The road thus gradually wears down, but always presents a uniform and smooth surface; and when its thickness is reduced to about five inches it is necessary to make general repairs by cov- ering it with a new coating of stone. The amount of wear is proportional to the volume of traffic. On some of the heavily traveled macadam streets of London and Paris it has been as much as four inches in a year, but on high roads between cities it is often as low as one-half inch in a year. Nowhere is the art of road-making and maintenance carried to such perfection as in France, where the necessity of constant supervision and prompt repairs is fully appreciated. Her roads have a length of about 200,000 miles, of wmVh more than 120,000 miles are macadamized. They have cost nearly $600,000,000 for construction, and the sum of $18,000,000 (or about three per cent, of first cost) is annually spent for their maintenance. Until we are prepared to expend the necessary sums for solid construction and incessant maintenance, we cannot have good roads. With an area of 204,000 square miles, and a population of 38,000,000 inhabitants, France has about one mile of road to every square mile of territory, and to every 190 inhabitants; its roads have cost about $3,000 for each square mile, and about $18 for each inhabitant; their maintenance costs annually $90 for each square mile, and 48 cents for each inhabitant. The State of New York has an area of 47,000 square miles, and a pop- ulation of about 6,500,000, the number of inhabitants per square mile being about three-fourths the number in France. On the basis of area, in order that its roads should be equal to those of France, their length should be 46,000 miles ; the first cost would be $138,000,000, and the annual cost of maintenance would be $4,140,000, or 64 cents for each inhabitant. The railroads of this State have cost nearly $900,000,000, and the annual expense of maintaining their road-beds is fully 6 per cent, of their first cost. It is evident that it would not be an impossible task to create a system of roads corresponding in excellence to the railroads whenever the necessity for them is fully recognized ; and it would not be difficult to prove that the benefits derived in cheapening the cost of transportation to the railroads, of which the roads would act as feeders, would be more than an equivalent for the expense. Nor would the cost in reality be anything like the large sums above named, for many of the existing roads contain an abundance of stone, which could be taken up, broken and relaid, after the manner in which Macadam rebuilt the roads of England, the cost of which is stated in his memoir to have been as low as $600 per mile. Owing to the increase in the cost of labor since Macadam's time, the cost would now be about $2, 500 per mile. ROADS. 267 It is worth while to note the manner in which France maintains these splendid roads. The data is all available in the ninth volume of Debauve's Manual for the Engineers of the Fonts et Chaussees. While we have no such large body of trained engineers in the public service, and while our political organization does not permit the adoption of the system as a whole, yet there are many of its features which are not only applicable to as, but are essential to any satisfactory method of road maintenance. The roads in each department in France are under the general super- vision of the Prefect of the department, and their construction and repair are entrusted to the engineers of the ponts et chaussees. The necessary funds for this purpose are allotted to each department by the Minister of Public Works. The high roads are divided into two classes national roads, running through two or more departments and connecting the chief cities, and departmental roads, connecting the principal cities within a single department. The local roads are divided into three classes the important local roads, the ordinary local roads, and the by roads. Each road is thus classified according to its use and the traffic upon it, as deter- mined by actual count at stated periods. The construction and the main- tenance are varied according to the use and the volume of traffic. Some of the national roads are paved with stone blocks, like city streets, for long distances; others are macadamized; and the local roads are of gravel. The engineer-in-chief has charge of all the roads in the department; under him are engineers having charge of certain districts, and under each of these are superintendents and overseers, each in charge of a certain length of road, and with a certain force of laborers and the necessary materials for keeping the road always in good order. It is, in short, the same system of constant inspection, maintenance and repair which is in use on every one of our principal railroads, but which is never applied to our roads. The fundamental principles of maintenance, as laid down in the Man- ual of Instruction, are only two in number viz.: i. The removal of the daily wear of the road, whether in the form of mud or dust; 2. The prompt replacement of this wear by new materials. Each road is divided into sections called cantons ; on heavily traveled roads a canton may be only 100 yards long, on light roads it may be a mile; and to each canton there is a workman known as a cantonmer, who is responsible for the condition of the road in his canton. He lives in the immediate vicinity, and is obliged to be on the road from 5 A. M. to 7 p. M. in summer, and from sunrise to sunset in winter; he can rest two hours for his noonday meal, but with this exception he must be always at work between the hours above stated. He has the following tools viz. : wheel- barrow, iron shovel, wooden shovel, pick, iron scraper, wooden scraper, broom, iron rake, crowbar, hammer and tape-line. His duties are : i. To keep the gutters clear so that the water can run off freely. 2. To scrape off the mud in wet weather and sweep off the dust in dry weather, so as to keep his canton always clean. 3. To clean off the snow as far as possible, and break up the ice on the surface of the road and in the gutters during the winter. 4. To pick up all loose stones, break them, and pile them in regularly shaped piles on the side of the road, ready for use in repairing ruts and holes. 5. To keep the mile-posts in good order. 6. To take care of the trees bordering the road. The six adjacent cantonniers form a squad called a brigade, which is under a foreman known as a cantonnier-chef, and forms the unit of work- 268 ROADS. ing force. Several brigades are placed under the charge of a conducteur, or superintendent, who has charge of a section of forty or fifty miles of road, for the good order of which he is responsible, and every part of which he must inspect and report upon twice a month. Several sections are placed under an engineer, who has charge of all the roads in an arrondis- sement, or township, and must inspect every part of them once in three months. Finally, the engineer-in-chief has charge of all the roads in the department or province, eighty-seven of which constitute the territory of France. During the winter, when the repairs are heavy, and whenever a gen- eral resurfacing of the road is undertaken, the regular cantonniers are assisted by auxiliary labor hired for the time being. The broken stone required for such work is furnished by contract, It should be borne in mind that this is not a mere paper organization, or code of forgotten statutes, but an actual working system in full opera- tion to-day. It is the result of 120 years of thought and labor devoted to an important subject by some of the best minds in France, and the result is the most superb system of roads to be found anywhere in the world. The cost is surprisingly small, considering what is accomplished. The actual cost per mile of maintaining the national roads (all macadamized) is given in Debauve's Manual for each of the eighty-seven departments. It varies from $60 to $500 per mile, with an average of $150, of which about half is for labor and half for materials. For maintaining less important roads the average cost per mile is as follows : departmental roads, $135 ; important local roads, $92 ; ordinary local roads, $57 ; by-roads, $42. It would seem as if a somewhat analogous system might be devised in America, by which the roads in each State might be placed in charge of the State Engineer, the repairs in each county to be made by the county survey, or according to the instructions of the State Engineer, a uniform road tax of, say, five mills to be levied throughout the State, but the amount of taxes raised in each county to be expended in that county. With an estimated valuation in the State of New York of $1,200,000,000 (exclu- sive of city property) for the census of 1890, such a tax would yield $6,000,- ooo per annum for the roads of the entire State ; and this sum judiciously expended, according to well-digested plans and under competent supervis- ion, would in a few years rebuild nearly all our important roads and main- tain them in good order.* The present system of independent action or inaction by each Board of County Commissioners is known to be a complete failure. What it costs for the entire State cannot be stated, for there are no statistics on the subject. Possibly, if the statistics were available, it would be found that the total cost is fully as great as the sum above stated, * A bill of a somewhat similar character is now pending in the Pennsylvania Legis- lature. It provides for a uniform road tax of seven and a half mills, to be raised in each county by a board of road commissioners, and expended under their direction by a county engineer, provided that not less than forty per cent, of the road tax shall be expended in macadamizing or other permanent improvement. The act further pro- vides that the County Engineer shall be appointed by the Court of Common Pleas, that the roads shall be classified into highways, roads, and lanes, that the county shall be subdivided into districts, each in charge of a supervisor, and that he shall make plans and specifications for all work upon roads, and report at stated periods concerning the same. The only defect in the proposed plan is its failure to provide some central supervision for the entire State, so that the roads should be constructed and maintained on a uniform system in the different counties. ROADS. 269 although the result is almost nothing. As for toll roads, and compulsory labor or a tax in lieu thereof, they are both out of date at the end of the nineteenth century. In brief, then, the only system for good country roads, as shown by universal experience, is a bed of stone, broken into small angular fragments and thoroughly rolled, and maintained in good order by a small force of laborers, under proper organization and supervision, constantly at work summer and winter in cleaning off the road and repairing any defects the moment they appear ; to which must be added, from time to time, accord- ing to the amount of traffic and resulting wear, a general renewal of the road surface with the same materials. Pavements. City streets are simply roads of very heavy traffic, and the problem of paving is road-making designed to meet certain special con- ditions. A vast amount of ingenuity has been expended in the effort to make pavements that would be indestructible, but the effort is entirely futile. In the constant attrition of wheels and pavement something must be worn, and if the pavement is indestructible the vehicles will soon be destroyed. That pavement is the cheapest which affords the least wear to its own surface and to the vehicles combined. A good pavement should be durable, smooth, cleanly, as nearly noiseless as possible, and afford a good foot-hold for horses. Every form of construction material iron, brick, stone,* and wood has been tried in every conceivable manner of applica- tion during the last fifty years. The results of this large experience as to cost and durability, ease of traction and cleanliness, noiselessness and slip- periness have been carefully studied by French and English engineers, and to a certain, though much less extent by American engineers. While it cannot be said that the exact amount of wear in terms of the traffic has been fully determined, nor that the effect of different pavements upon the wear of vehicles and the cost of transportation has been mathematically demonstrated, yet certain fundamental principles are now generally admitted by all who have given careful thought to the matter viz.: i. A foundation is necessary, which constitutes the real pavement, and which is indestructible. 2. On this foundation a suitable wearing surface should be laid, and renewed from time to time. 3. The only suitable wearing surfaces are stone blocks, asphalt, and wood. In reality these principles are only a development of the macadam road. Since the surface of macadam is worn too rapidly by heavy traffic, it must be protected with a renewable surface, leaving the body of broken stone as the permanent road-bed. As broken stone and cement mixed with sand will acquire in a few days the solidity that macadam will attain only after several months or years, the bed of macadam metal has naturally given place to a bed of concrete. This is universally conceded to be the proper foundation for any good city pavement. A thickness of six inches has been found by experience to be amply sufficient ; in cases of exception- ally heavy traffic it should be made of Portland cement, but in all other cases the ordinary American cements are quite strong enough. In selecting the wearing surface, due regard should be had to the gradient, the traffic and the climate. Stone blocks are the most durable, but they are the most expensive, the most noisy, and offer the greatest * Asphalt pavements are really a form of stone. The asphalt which they contain acts as a cement to hold together the limestone or sand which forms the body of the material, being from 85 per cent, to 95 per cent, of its weight 270 ROADS. resistance to traffic. Asphalt is the smoothest and cleanest, but it should not be used on grades of more than 4^ in 100. Wood is the least durable, but it is smooth and noiseless. Among different kinds of stone, sandstone and limestone are not sufficiently durable, and trap is so hard that it polishes and becomes very slippery under traffic. Hence, granite is consid- ered the best stone to use. Of asphalt there are two varieties, the natural bituminous limestone of France and the artificial bituminous sandstone, made by mixing sand with pure asphalt, which is largely used in many American cities. Of wood many varieties, both hard and soft, have been used, but the best wooden pavements of London and Paris are made of Baltic fir. Acting on these general principles, engineers have usually recom- mended granite blocks in streets of heavy traffic or steep grades, and asphalt or wood for residence streets. They have for many years con- demned macadam as a city pavement on account of its lack of durability and because it cannot be kept clean, being always muddy when watered and dusty when dry. There are still large areas of macadam in the cities of Europe as well as of New England, but the expense of maintaining them is so great that they are being replaced as rapidly as possible. The wood pavement on a concrete foundation has not been popular in America on account of its lack of durability, the wood surface requiring renewal every five or six years ; but it is largely used in London and Paris. The granite block surface has been used more largely than any other, an undue importance having been attributed to the element of durability, regardless of all other qualities. But of late years the questions of noise- lessness, cleanliness and ease of traction have been more fully considered, and the result has been a large development of smooth-surface pavements /. pounds = 2.09 - 2.61 mile tons per cubic yard of macadam. The advocates of the steam road-roller claim that by means of that machine they are enabled to make a road that will wear out evenly and uniformly for four or five inches, so that the operation of patching need never be resorted to. The steam road-roller can also be used for "picking" up a road, for which purpose the roller is armed with sharp spikes, and is then driven over the surface to be "picked" up. Pavements and Trackways. No essay on roads would be com- plete without some mention of these two species of road surface, though the use of the former is confined principally to streets, and that of the latter is out of date. Pavements are either of stone, wood, iron, various concretes, asphalt, and may be of still other substances. Stone Pavements. The modern sizes of paving stones may be seen from the following cases: The Boston size is 4j"x3j"x7 // deep; New York Belgian, 6" to 8" x 5* to 6" x 6" to f deep; new Broadway pavement, also called Guidet pavement, 3^" to 4 1 " x i o" to 1 4" x 7 \ " to SI" deep. This last is laid with the long sides of the stones across the street; and, as far as the author's judgment goes, is the best size for stone pavement there is. The Boston size is too small, and allows of no bond between the separate paving stones. Further, the weakest part of each stone being its edge, it follows that the more edges there are in a given surface of pavement, the speedier will it wear out, each stone becoming rounded and slippery. It is only ROADS. 329 the excellent workmanship and great care displayed in setting these stones in Boston that prevents these facts from being at once appar- ent to all. When it is added that in setting pavements, the natural soil, except it be sand or fine gravel, is in all cases to be excavated 12 to 19 inches, and then filled up 5 to 12 inches, according to the solidity of the subsoil, with clean, coarse sand or fine, clean gravel, and the paving stone set in this and well rammed down with hand- rammers; about as much is said on this topic as can be said without going into long details. From 4j to 6 cubic feet of sand are required for every square yard of paving. In setting two different pavements, the same writ- ten rules may be exactly followed in either case, yet one be much better than the other, so much depends here upon good, careful, conscientious workmanship. Wooden Pavements. There are so many kinds of these that it would be out of place to enumerate and describe them all here. Their advantages are less wear on tires and horses, less noise and smooth traction; a disadvantage is their slipperiness in the winter. There seems to be a sort of notion that wood pavements and coal tar must go hand-in-hand; but there certainly is no necessity for this. Coal tar is applied as a preservative to the wood; but it must be acknowledged that many better ones are known, and indeed are used, to the utter exclusion of coal tar, in all cases where it is desired to preserve wood, except in this of wood pavements. No wood should be used in paving that has not been first sub- jected to some approved method of preservation, or impregnation, as it is frequently called. The best manner of setting the same is still a mooted point, which it would be presumptuous at present to decide. A valuable contribution to the subject of wooden pavements is the report of the Commission appointed by the City of Boston to consider this subject, in 1872, City Document No. 100, 1873. The Commission comes to the conclusion that the best way to preserve the wood that is put down is by the method called Burnettizing, after its inventor, Sir H. Burnett, of England, in 1838. It consists of treating the wood to be preserved with chloride of zinc. The Commissioners wisely add: "Your Commissioners are of the opin- ion that if the city adopts any method of preserving blocks to be used for pavements, some additional security should be had that the treatment of the wood shall be thorough and complete." As regards the construction of the pavement, the Commissioners rec- ommend spruce blocks (for this section of the country), lay stress on the necessity of a solid, uniformly constituted and rolled gravel foundation, and then say: " The rows or blocks should be set square 330 ROADS. across the street, and should be about four inches thick at top, with spaces of about one-half inch between the rows. This may be done with blocks of uniform thickness set apart, or with tapering blocks half an inch thicker at bottom than at top. The latter arrangement is the more costly, but it is believed by some that it will stand better, by reason of its covering the whole surface of the foundation. Longer trial is necessary to settle this point beyond dispute. Blocks of only a short chamfer at the top leave the inter-space too narrow, as the blocks wear down." The Commission named consisted of "two chemists, two practical mechanics, and one civil engineer." Cast-iron pavements are out of favor on account of their great cost, and concrete pavements are a matter of experiment as yet. Asphalt pavements are chiefly used in Paris. They are slip- pery in wet weather, and produce a very disagreeable, penetrating dust in dry weather. It is necessary to prepare a bed of macadam to lay them on, and they are not used in Paris except in streets where the gas-pipes are carried either in the sewers or under the sidewalks, as any leak of gas would destroy them. Their use is a matter of doubtful economy. Trackways are, as has been mentioned, out of date. Where a common road does not suffice nowadays, a railroad is built; but time was when trackways were of considerable importance. They consist, if of stone, of large, flat stones, say 12 inches deep and 4 to 6 feet long by 14 to 16 inches wide, solidly bedded in two parallel rows, at such distance apart as to make of each row a track for the wheels. The space between is paved. They are, of course, very expensive, but cost little to repair, and enable a horse to pull a very great load. As has been mentioned, Telford made use of such a stone trackway to avoid cutting down a hill on his Holyhead road. There were two hills, each a mile in length, with an inclination of 5 in 100. It would have cost $100,000 to reduce this grade to 4-J- in 100, but nearly the same advantage, in diminishing the tractive force required, was obtained by keeping the 5 in 100 grade, with moder- ate cuttings and embankments, and making stone trackways, at a total expense of less than half the former amount. " Plank roads," once so much in vogue in the United States, may not improperly be classed among roads with trackways, and, with them, also among the things that were. From their perishable nature, they can never advantageously do more than help the devel- opment of a new country, and in this, as well as other States, are yearly becoming more and more impracticable on account of the constantly increasing price of lumber. On the Resistance to Motion or the Force Required to Move Vehicles on Different Kinds of Roads. Before, as well as since the ROADS. 331 introduction of railways, engineers in England, Germany and France made many experiments on the force necessary to pull different vehicles, at various speeds, over various surfaces. To enumerate the details of all these experiments would be perhaps useless ; a few general results only are here given. Experiments, as above indicated, were made by Edgeworth, Count Rumford, Bevan, MacNeill, Minard, Navier, Perdonnet, Pon- celet, Flachat, Morin, Kossak, Umpfenbach, Gerstner, and no doubt others, a list of authorities that proves the subject to have been well nigh exhausted. The experiments of Morin, made in 1838-41, appear to have been made with a degree of care and accuracy, leaving nothing more to be desired. Table X. is an extract from his results,* and gives that fraction of the weight of the vehicle and load which is required to move them on a level road : TABLE X. CHARACTER OF THE ROAD. Character of the Vehicle. 2- wheeled carts. Trucks, 4-wh 3 and 4 horse. I 8 " ||| 000, jtlom V i si a ifl #G i 1* O Firm soil, covered with gravel 4 to 6 inches deep ft I 1 . i * A i i ft & TV I Vo V 43 Firm embankment, covered with gravel i^ to i^ inches deep Earth embankment, in very good condition ... Bridge flooring of thick oak plank . . . BROKEN STONE ROAD. In very good condition, very dry, compact and even ! TV t ft Walk. TV 1 ft Trot. t ft Walk. t a 1 , i 1 , Trot. 4 1 * .'> TV TV A little moist or a little dusty Firm, but with ruts and mud Very bad, ruts 4 to 4^ inches deep, thick mud ,. (Drv.. 4 $ t * t Good pavement Covered with mud * A full account of Morin's experiments on the resistance to motion of vehicles, on the wear caused by different vehicles on roads, and on the loads different vehicles should carry so as to produce the same wear, may be found in Morin, " Experience sur le tirage des Voitures," Paris, 1842. 332 ROADS. To take an example, suppose we have a truck weighing with its load 9,000 pounds. How many pounds traction will be required to move the same ? Ans. On firm soil, gravel 4 to 6 inches deep that is, a newly repaired road, as we often find it ( by table), 1,000 pounds ; on best kind of embankment (f ff by table), 310.3 pounds; on broken stone road in good condition (-g 1 T by table), 166.6 pounds ; on broken stone road, deep ruts and mud (^ by table), 643. pounds ; on a good pavement (-fa by table), 138.5 pounds. Or, since the tractive force of a medium horse when working all day is said to be about 125 pounds, we need in the first case, 8 horses ; in the second case, 2 J horses ; in the third case, about i horses ; in the fourth case, about 5 horses ; and in the fifth case, only one good horse to move the same entire load all day. These facts, expressed in Table X. in striking yet perhaps dry figures, can be nearly as well given in popular language. Says a correspondent (Dr. Holland), of the Springfield Republi- can, writing from England, after describing the kind of horses in use there : "Now, with all these horses the rule follows that every pound of muscle does just as much work on the road as two pounds do in America. The cab and omnibus horse does twice as much as the same horse does in America. The draft horse does as much in the dray as two ordinary dray horses in America, and the little horses, which are driven mainly in butchers' carts and grocers' carts, will tire a cab horse to follow them with no load at all. " In connection with these statements it should be recorded that the speed of all vehicles in the streets of London, whether the localities be crowded or not, is at least a third faster than it is in corresponding streets in American cities. The ordinary speed of vehicles in London, in which passengers or light loads are transported, is one which is considered not entirely safe in Main Street, Springfield, Mass., and one which, in some streets of Boston or New York, would be at once checked by the police. A man who sits in a ' Hansom ' finds himself driven at an unprecedented pace through crowded thoroughfares, and, Yankee though he may be, he will often wonder whether he is going to bring up at last without a broken neck. "I mention this matter of speed, particularly, because it shows that even more work is done by one horse in London than by two in New York. He not only draws as large a load, but he travels with greater rapidity. The streets of London present such a spectacle of headlong activity as no American city can show, in consequence of the rapid passage of all sorts of vehicles through the streets. I might add to this statement, touching the superior speed of the London horses, a word about the greater weight of the carriages which they are obliged to draw behind them. All carriages are built more heavily in Great Britain than in America, They are built to last, and many of them seem to me to be superfluously heavy. ' ' The point which I wish to impress upon my American reader is simply this : that the English horse, employed in the streets of a city, or on the roads of the country, does twice as much work as the American horse ROADS. 333 similarly employed in America. This is the patent, undeniable fact. No man can fail to see it who has his eyes about him. How does he do it? Why does he do it ? These are most important questions to an American. Is the English horse better than the American? Not at all. Is he over- worked? I have seen no evidence that he is. I have seen but one lame horse in London. The simple explanation is that the Englishman has invested in perfect and permanent roads what the American expends in perishable horses that require to be fed. We are using to-day, in the little town of Springfield, just twice as many horses as would be necessary to do its business if the roads all over the town were as good as Main Street is from Ferry to Central. We are supporting hundreds of horses to drag loads through holes that ought to be filled, over sand that should be hard- ened, through mud that ought not to be permitted to exist. We have the misery of bad roads, and are actually or practically called upon to pay a premium for them. It would be demonstrably cheaper to have good roads than poor ones. It is so here. A road well built is easily kept in repair. A mile of good macadamized road is more easily supported than a poor horse." Other results of Morin's experiments are as follows : 1. The force required to draw a vehicle, is directly proportional to the load and inversely so to the diameter of the wheels ; in other, more common, words, the tractive force increases in the same ratio that the load increases, and the diameters of the wheels decrease. 2. On a paved or well built macadam road, the tractive force is independent of the width of the tires, provided the same is more than three or four inches. On compressible roads, such as new tgravel, on a meadow, etc., the tractive force diminishes with an increase in the width of the tires. 3. Other circumstances being equal, the tractive force is the same for vehicles with and without springs, as long as the horses are not moving faster than a walk. 4. On paved and well macadamized roads the tractive force increases with the velocity, according to the law, that beyond a velocity of 2 J miles per hour (3 T 3 7 feet per second) the increase of the tractive force is in direct proportion to the increase in velocity ; his increment is, however, less, the softer the track or road and according as the vehicle is best provided with springs. 5. On soft earth embankments, or on sand or sods, or on streets newly covered with gravel, the tractive force is independent of the velocity. 6. On a well made pavement of regular shaped stone, the trac- tive force, horses on a walk, is about three-fourths of that on a good macadam road, but with horses on a trot, the two are about equal. 7. The wear on the road is greater the smaller the diameter of the wheels, and greater in the case of vehicles without than for those with springs. Most road-rollers, as now in use, have too small a 334 ROADS. diameter, besides being too light, and consequently do not properly compress the road surface. 8. The tractive force, as well as the wear on the road, is greater in the case of vehicles that have their wheels placed at an angle with the vertical by reason of the ends of the axle-trees being bent down, than for those that have their wheels set plumb and the center line of the axle-trees level. PART II. On the " Best Methods of Superintending the Construction and Repair of Public Roads in this Commonwealth." In looking for a solution of this question the people of the Commonwealth may turn as they choose, either to the West or to the East, to see a guiding star : to the city of Chicago, or to the city of London, both under a republican form of government, alike or similar to that under which we live. It lies in the establishment of a Board of Public Works, composed of a number of able men, well paid for their services, gradually changing in their membership in the board who shall have this and only this as their occupation and who can therefore be held responsible for their acts. This is the system that has been adopted both in London and in Chicago and with remarkable success and resultant benefits. There are many other systems in use in foreign countries, all of which, how- ever, seem to be inapplicable here, placed as we are under so differ- ent forms of government ; hence, though well acquainted with the systems adopted in France and in Germany, the writer has not described them here. Experience in London. The history of the " Metropolitan Board of Public Works of the City of London " is about as follows : What is known as the city of London consists in reality of a great number of what we should call towns, there called parishes, and of which the city of London is only one single member. Each one of these parishes had, and still has in most respects, its own local government and in consequence took care of its drainage, its streets, etc., etc., as seemed best and as it liked, some better, some worse and some not at all. This state of things in the matter of drains and sewers finally led to a most deplorable condition of affairs ; there was not, nor could there under these conditions be, such a thing as a system of sewers and consequently a proper and adequate drainage ; the death-rate increased to an alarming extent and matters came to be universally regarded as past all endurance. What could be the remedy ? No well-grounded complaint could be made against the majority of the men composing the various local governments, since they were good and honest citizens, and hence ROADS. 335 no change in the separate governments could ever bring relief. The fault lay not in the men, but in the system of ruling they were called upon to fulfil that is, in the incompetent and faulty tread-mill of government they were annually called upon to keep in its usual operation. It was then seen that by having an elected power to supervise and regulate the sewage affairs of the whole metropolis, a complete system of drainage could be carried out, and thus only. Such a regulating power is exercised by the Metropolitan Board of Public Works, chartered by Act of Parliament and composed of members elected from all parts of London. It is, perhaps, in place here to explain what is meant by a system of sewers, as the same definition will hold good in other matters ; as for a system of roads, of drainage and irrigation of lands, etc. Perhaps the best illustra- tion would be to refer one to the veins and arteries in the human body, or to the body of a tree, from its trunk through the branches growing smaller and smaller down to the smallest twig that may be on it. It will be at once seen how different any arrangement, in which may be detected the wisdom to contrive, the strength to up- hold and the beauty to adorn, like this, is from a miserable patch- work such as cannot but arise where the separate parts of one whole are each left to guide themselves without any unity of action or design, as to their final resultant. The London Board of Public Works had some extraordinary powers conferred upon it, such as the right to levy assessments on real estate benefited by their im- provements, and others. Originally constituted merely to plan and execute a system of sewerage for the metropolis, this Board of Public Works soon showed itself so useful and beneficial in its actions that other matters were placed in its charge, such as the laying out of new streets the building of the Thames embankment a work of exceeding great magnitude and importance and there seems to be no doubt that in all public works London will find it advantageous to employ its Metropolitan Board of Public Works. Experience in Chicago, In the city of Chicago there has been a Board of Public Works almost from the very start. It arose there from the union of the water-supply and the sewerage commission- ers, and has existed since May, 1861. No less than in London, it has proved to be of great benefit to the community ; and it would have been impossible, under any other system, to have executed in so satisfactory a manner the many and useful public works for which Chicago is famed. At the risk of introducing in this place some very dry reading, a general synopsis of those parts of the city charter which relate to the Chicago Board of Public Works is here given. The whole may be found in a copy of "Laws and Ordinances, Chicago, 1866." 336 ROADS. SECTION i. Establishes a body known as the Chicago Board of Public Works, to consist of (3) three members, chosen by the people, one from each division of city. The first three chosen for one, two and three years ; after that, one each year for three years, SEC. 2. Each member of Board shall receive annual salary of $3,000 (by Act of February, 1866) ; give bonds for faithful discharge of duties ; pay over all moneys, papers, etc., at expiration of his term, or when ordered by City Council. SEC. 3. Board to elect president and treasurer, and make by-laws. SEC, 4. Majority constitutes quorum ; records to be kept of proceed- ings ; copies of all plans, estimates, etc., to be kept ; report (annual), to be rendered on or before each year, or when required by City Council. Each member authorized to administer legal oaths. SEC. 5. Board shall have special charge and stiperintendence, subject to the laws and ordinances of City Council, of all streets, lanes, alleys, etc., in the city of Chicago, and of all walks and crossings in the same, and of all bridges, docks, wharves, public places, landings, grounds and parks in said city, and of all halls, engine-houses, and other public buildings in the city belonging to city, except school-houses, and of the erection of all pub- lic buildings; of lamps and lights in streets, etc., and in public buildings, and repairs of same; of the harbor works and improvements; of the city sewers and drains and of the water- works; of the fire-alarm telegraph, and all public works and improvements hereafter to be commenced by the city, as well as such other duties as may be prescribed by the City Council by ordinance. SEC. 6. All applications or propositions for improvements, or new works of kind specified in section five, shall hereafter be first made to Board of Public Works, or if first made to City Council, shall be by them referred to Board. Upon receiving application, Board shall investigate the same, and if they find such work necessary and proper, shall thus report to City Council, with an estimate of the expense thereof. If they do not approve of such application they shall report the reasons for their disapproval, and the City Council may then, in either case, reject said application or order the doing of work or making of public improvement, after having first obtained plans and estimates thereof. The Board may also in like manner recommend, whenever they think proper, any improvement of the nature above specified, though no application has been made therefor. SEC. 7. Shall be duty of Board to procure for city full plans and esti- mates of contemplated improvements, when so ordered by Council. SEC. 8. Whenever any public improvement shall be ordered by City Council, and money appropriated, Board shall advertise for proposals for doing work ; plans and specifications of same first placed on file in office of Board, which plans and specifications shall be open to public inspection; advertisement to state work to be done, and to be published ten days at least. The bids shall be sealed bids, directed to Board, and accompanied by bond to city, signed by bidder and two responsible sureties, in sum of $200, conditioned he shall do work if awarded to him; in case of his default to do so, etc. Bids to be opened at time and place mentioned in advertise- ment. ROADS. 337 SEC. 9. All contracts shall be awarded to lowest reliable bidder, and who sufficiently guarantees to do work under superintendence and to satis- faction of Board; provided, that the contract price does not exceed the esti- mate, or such other sum as shall be satisfactory to Board. Copies of con- tracts to be filed with City Comptroller. SEC. 10. Board reserves right, in contracts, to decide questions as to proper performance of work and meaning of contracts; in case of improper construction may suspend work and re-let same, or order entire reconstruc- tion; or may re-let to other contractors and settle for work done, etc. In cases where contractor properly does work, Board may, in their dis- cretion, as work progresses, grant to said contractor estimate of amount already earned, reserving 15 per cent, therefrom, which shall entitle holder to receive amount, all other conditions being satisfied. SEC. ii. In case prosecution of any public work be suspended, or bid be deemed excessive, or bidders be not responsible, Board may, with written approval of treasurer, where urgency of case and interests of city require it, employ workmen to perform or complete any improvement ordered by Council; provided, that the cost and expense shall in no case exceed the amount appropriated for the same. SEC. 12. All supplies of materials, etc., when costing over $500, to be purchased by contract, subject to same conditions as letting out work. SEC. 13. Whenever Board think necessary for interests of city, to pro- tect same from damage or loss, shall report thus to aldermen, and reasons for same, asking power to give contracts without notice required above, and aldermen may grant request; provided, three-fourths vote for it. SEC. 14. Whenever Board is of opinion work may be better done with- out contract, shall so report to Council, and same may authorize Board to procure machinery, materials, etc., hire workmen, etc.; provided, a three- fourths vote be in favor ef granting authority. SEC. 15. All contracts and bonds by Board to be in name of city. SEC. 16. No member to be interested in any contract; all contracts made with any member interested, city may declare void; any member so interested shall forfeit his office and be removed therefrom ; the duty of every member of Board and of every officer of city to report delinquency, if discovered. SEC. 17. All existing contracts executed by city, by water or sewerage department, etc., to be carried out by Board. SEC. 18. Board shall nominate each year the various officers, now pro- vided for by ordinance, which serve in the departments under their special charge, the city engineer, superintendents sewers, streets, etc. Shall be empowered to employ from time to time such other superintendents, clerks, etc. , as they may deem necessary, subject to ordinance as regards pay, etc. SEC. 19. Board to have charge and superintendence of works made for city, and paid for by private individuals or by State. Plans for same to be approved by Board. SEC. 20. Board shall, on or before every year, submit to auditor, by him to be presented to Council with annual estimate, statement of the repairs and improvements necessary to be undertaken for current year, and of the sums required by Board therefor ; report to be in 33 8 ROADS. detail ; report, having been revised by Council, sums required shall be pro- vided for in annual tax-levy. All moneys to be paid to any person out of moneys so raised, shall be certified by president of Board to auditor, who shall draw warrant on treasurer therefor, stating to whom payable and to what fund chargeable; such warrant to be countersigned by president of Board. SEC. 21. Board to keep accounts, showing moneys received and spent, clearly and distinctly, and for what purpose. Accounts to be always open for inspection of auditor or any committee appointed by City Council. The object of introducing this synopsis here has been to give a complete picture of just what such a Board of Public Works is. It will be seen upon a little examination how entirely different a thing it is from the usual and only too customary "committee." Perhaps the greatest fault of a committee is its entire lack of what might be called body and soul. If corporations, as has been said, have no souls, a committee may be said to have neither body nor soul. It is alive to-day, wields great power, decides vital and important ques- tions, and yet is nowhere to-morrow, and seemingly even its compo- nent atoms have vanished from the face of the earth. It is amusing and yet sad, when the action of some such committee has caused trouble to read some time after, that it all " is exceedingly discredit- able to whoever is responsible for it." How much better to have a conservative, expert and reliable body, the members of which have no other business than to attend to their duties as such, who are well paid for it, and consequently can at any time be held strictly responsible for their actions. With such a power, wisely governing and regulating the roads of this Commonwealth, it would be an easy matter to make thorough improvements in the legislation concerning roads and in the roads themselves. These are two changes the need of which is generally felt at present and has found expression in various ways. It may be well to quote one at least, notable for saying very much in little compass, of these calls for improvement, in this con- nection, and adding some more as belonging to their subject in the form of an interesting appendix. Says Governor Claflin in his Inaugural : " Few things are of greater importance to a community, or a surer test of civilization, than good roads. Those of our citi- zens who have visited Europe are unanimous in the opinion that our public roads are far inferior to those of other countries, where the means of easy and safe communication are better appreciated. The science of road-making is apparently now well understood ; or, if it is, the present modes of superintending the construction and repair of roads are so defective that the public suffers to an extent of which few of us are aware. It may be found upon investigating the cause of our miserably poor and ill-constructed roads, that the laws ROADS. 339 relating to this subject need revision, so as to give more uniformity in their construction and the repair of our highways. It is evident, also, that the science of road-making should have a prominent place in the course of applied mathematics at the Massachusetts Agricult- ural College." We stand in this matter of roads at precisely the same point that the good people of London did ten or a dozen years ago in the matter of their drainage, and our remedy is the same. The fault lies in the machinery of Government ; originally built up to cater to the wants and needs of a newly settled country a colony breaking a path through the wilderness it has long since ceased to satisfy the demands of the present State in no matter so essentially as in that of its government and laws relating to common roads and high- ways. This is a subject requiring special knowledge, to be acquired only by long experience or the shorter method of imbibing the expe- rience of others, which on analyzing it, is all that any study amounts to ; formerly it was not so, and most any one sufficed to make improvements on Indian paths. We need then an expert govern- ment on this point. There should be a distinction made between first, second and third class, or between, as they might be called, State, County and Town roads; the first two should not be left to be dealt with as it is the pleasure of each town. A chain cannot be perfect unless every link in it is so ; no more can a road. The State must attend to the State and County roads and set a proper example at least to be fol- lowed by the towns in the case of their roads. We need then a higher power than that of the towns. It has been previously shown how we need a power that can be held responsible and is somewhat permanent, and to put it all together, we need, to order and maintain our highways, a Massachu- setts Board of Public Works. For some years, it would have its hands full in improving the existing main roads and laying out some new ones, but in course of time, as in the older countries of Europe, its principal business would be the maintenance of the roads. It must be remembered that the Board of Public Works is merely the intelligent servant and adviser of the legislative and executive ; whatever sums the Legislature appropriates for certain objects, that is taken by the Board and made to yield its most in the shape of work accomplished. Beyond this and keeping its accounts, it has nothing to do with money or taxation. The small State of Baden, a part of Germany, has been hereto- fore mentioned as a model in road construction and the care of the same. From the brief history of the roads of that country and their repsent management, we may take some useful notes. The account 34 ROADS. is that of the Chief Engineer of the department of " Roads and Hy- draulic Engineering," which has this matter in charge and is there- fore reliable. " In Baden the condition of the roads has been the subject of great care. Within the last forty-five years many millions have been spent upon them and experience has shown this expenditure to be one of those most advantageously spent. As most of the roads are well laid out and as there are plenty of them, there remains now (1863) mainly the keeping in repair of the roads to be attended to and not to build any new ones. Our endeavor now is to do this at the minimum of cost. Statistics gathered on this subject show good results and point out to us the means of arriving at still better ones. The present road law was made in 1810. That part of the old law which relates to the maintenance of roads is still in force, but that part requiring labor as a road-tax was abolished in 1831, and likewise most of the road police regulations. The appropriation for roads had to be increased 250,000 florins to pay for the abolished road-tax labor and to make up 170,000 florins previously received from tolls, which were also abolished in 1831. The system now is as follows : All town roads are taken care of by the towns. The State merely appoints and pays a roadmaster, so called, who superintends fifteen or twenty roadkeepers and reports on the state of the roads, the reasons for their bad condition, if that be the case, what is needed, etc. The law for second-class or county roads was formerly, that when they were of importance to several towns, they had all to help maintain the same. As this gave rise to continual bickering and quarrelling, in which the road suffered most, it was changed in 1856. They are now taken care of under the direction of the State and paid for partly by the State and partly by the towns in which they are situated. Most of the roads under this head are those which have risen in importance since the building of railroads, and are generally those that lie perpendicular to the direction of the railroad they are influenced by. The towns not having the means very often to properly improve and repair such, it was found necessary and ex- pedient to give them the aid of the State, and in order to procure the necessary funds, all roads that run parallel to railroads and all those that had lost their importance by the construction of railroads, were in 1855 stricken from the list as State roads. These latter, as the name implies, are wholly under the care and kept up at the ex- pense of the State. Table XI. gives the total lengths of the roads at various periods. ROADS. 341 TABLE XI. In 1835, the total length of the State roads was 1,430.8 English miles. In 1855, " ** '* " " 1,500.8 In 1855, by excluding several State roads, this last length was reduced to 1.142.4 " In 1 861, it had increased to 1,190.0 " Second-class roads (keeping partly paid for by State). In 1835, the length of these was , . . 467.6 English miles. In 1861, the length of these was 630.0 " " The areas, population, and population per square mile of Baden, Prussia, France, Hanover and Massachusetts, according to recent census, are as follows : Country. Year. Area, Sq. Miles. Population. Population per Sq. Mile. Baden 1871 5,891 1,461,562 248 Prussia 1871 134,045 14,643,698 184 France 1872 204,088 36,102,921 177 Hanover 1871 14.857 1,963,080 132 Massachusetts 1875 7,800 1,651,912 212 Baden did have, at the time when her population per square mile was less than it is now, and Prussia, France, Hanover and many other countries that could be named, have now got, and for the past 40 or 50 years have had, a system of common road manage- ment and resultant common roads, of the character above described; while Massachusetts with a population of 212 per square mile, and corresponding wealth, and others of the States of the Union, have a species of highway management, and its resultant and correspond- ing sort of highways, which, in thinking of the roads of the coun- tries named, are but as evidences of a partial civilization. " So that the State had, in 1861, in all, 1,820 English miles of road to maintain, the towns helping to pay on 630 miles thereof. * * According to "Chambers' Encyclopaedia," Baden has an area of about 5,900 square miles, and had a population in 1858 of 1,335,952. It is probably this, or a little less, at the present time. Massachusetts has an area of about 7,800 square miles, and, according to the average of the com- puted populations in the supplementary tables of the census of 1865, it is, in 1870, 1,343,604. Or, population per square mile in Baden = 226.43 " " " " in Massachusetts = 172.26 By the same tables, accompanying the State census of 1865, we find that the population per square mile in Massachusetts will equal that of Baden, above given, somewhere between 1890 and 1891. It exceeds that of Prussia, and probably equals that of France at the present day, both of which countries have systems of roads and road-repairing but little, if any, inferior to those of Baden. 34 2 ROADS. " The statistics of the road repairs are kept in the following manner: The roadkeepers are required to keep a record of all draught animals that pass in either direction. Horses that are being ridden, animals not before a vehicle, and teams going to and from the fields, are not counted. These records are kept only during the working hours. Likewise, not during the whole year, but only four months in each year, so selected as to give an average amount of travel. The travel on the road on Sundays and out of working hours is taken from a few observations ; it is a very small percentage of the whole. At the end of the year these records and observations are collected and graphically represented on a map of the whole State. The different roads are drawn of a different thickness of line, according as the amount of travel on them is greater or less. The quantity of road metal used per yard of road, and the kind of metal used, give the data for another such map, in which the differ- ent colors of the roads represent the different materials used in their repair, and the figures on them and their thickness show the number of cubic yards per mile required to keep the road in order. Finally, we have a third map, which indicates, by the thickness of the several lines representing the roads and by the figures on them, the total cost per mile of repairing the road one year." With this picture of a country happy and prosperous, in the possession of good and well kept roads, it may be well to leave the subject. Massa'chusetts wants, for her proper development, much better roads than she now has; and reckoning for a period of, say fifty years, she can have these good roads, and have them kept in order at a less cost than that of keeping up the present poor ones for the same time. Besides this, we should see in the one case a healthy state of internal communications and trade ; in the other an absence of both. Let each citizen so act and do his part, that these benefits may accrue to the Commonwealth. NOTE BY THE SECRETARY OF THE MASSACHUSETTS BOARD OF AGRICULTURE. For the sake of arriving at some practical end, I have requested the gentlemen to whom the prizes for essays were awarded, to sug- gest what form of legislation would be desirable as a change, from our present inefficient system of road management, to one which would promise better, more economical, and more satisfactory results. The large and varied experience and observation of these gentlqmen, all of whom are competent engineers, entitle their opin- ions and judgment to favorable consideration; and the following, sub- mitted by them, may serve as a basis or outline for future legislation: ROADS. 343 AN AC '7' for tJie More Perfect Construction and Maintenance of the Common Roads or Highways Throughout this Commonwealth (Massachusetts), SECTION i. Establishes a body to be known as the State Board of Highways and Bridges, to consist of three skillful civil engineers, or per- sons practically expert in the science of road-making, to be appointed by the Governor, with the advice and consent of the Council, and to have their office in the State House. SEC. 2. It shall be the duty of the Attorney-General, personally or by his deputy, to give his counsel and opinion on such matters as he may be called upon by the Board, for which service his compensation shall be SEC. 3. The first appointment of members of the Board of Highways and Bridges shall be made on or before , and there shall be appointed one member each for the terms of one, two, and three years; after that there shall on or before each year be appointed one mem- ber for the term of three years. SEC. 4. Each member of the Board shall receive an annual salary of dollars ; give bonds for the faithful discharge of his duties ; pay over all moneys, papers, etc., at the expiration of his term, or when ordered by the Governor and Council. SEC. 5. Board are to elect a president and treasurer, and make their own by-laws. SEC. 6. A majority of the Board constitutes a quorum ; records to be kept of all the proceedings ; copies of all plans, estimates, etc., to be kept ; report to be rendered on or before each year, or when required by the Governor and Council. Each member authorized to administer legal oaths. SEC. 7. Said Board shall prepare and submit to the Legisla- ture a plan for the systematic classification of all the highways and townways in this Commonwealth into two or more of the following three classes: Class i. State roads, to be controlled and maintained wholly by the State. Class 2. District roads, to be controlled and maintained by the State, but the expense thereof to be borne by the towns and cities of the districts in which said road shall lie, and the State, in such proportions as said Board shall apportion. Class 3. Town roads to be controlled and maintained as now provided by law. The construction ot new road roads, of the three classes above speci- fied, to be done as follows: Class i. State roads, to be laid out and built by the State, through the Board of Highways and Bridges. Class 2. District roads, to be laid out, etc., by the County Commission- ers, as now provided, but the Board to have the final approval or disap- proval of the proposed plans and profiles for said road, and also to have the charge and superintendence of their construction. Parties aggrieved by the refusal or neglect of County Commissioners to lay out a road, to have the right to appeal to the Board of Highways. Class 3. Town roads, to be laid out and constructed as now provided by law. 344 ROADS. SEC. 8. The paying of road taxes by labor is hereby abolished, and all road taxes are hereafter to be paid in cash. SEC. 9. Board shall have the special charge and superintendence, sub- ject to the laws and resolves of this Commonwealth, of all the highways and bridges and the public works appertaining thereto, which are or shall be executed or maintained wholly or in part by this Commonwealth. They shall also perform such other duties as may be required of them by the General Court or the Governor and Council. SEC. 10. Whenever any highway or bridge, or public work appertain- ing to these two, shall come partly within the province of this Board and partly within that of any other State Board already constituted, then such subject shall be discussed and decided upon in a joint convention or con- ventions, composed of equal numbers of this and the said other State Board, and some member by them chosen as presiding officer. SEC. ii. All applications or propositions for improvements or new works of the kind specified in section nine as coming within the province of this Board of Highways and Bridges, and intended to be laid before the Legislature, shall hereafter be first made to this Board. Upon receiving such application, Board shall investigate same, and if they find such work necessary and proper, shall thus report to the Legislature, with an estimate of the expense thereof ; if they do not approve of such application, they shall report their reasons for their disapproval. The Board may also, in like manner recommend, whenever they think proper, any improvements of the kind above specified, though no applica- tion has been made therefor. SEC. 12. It shall be the duty of the Board to procure for the Legislature full plans and estimates of contemplated works or improvements when so ordered by the Legislature. SEC. 13. Whenever any work shall have been authorized or ordered by the General Court and the money appropriated therefor, Board shall adver- tise for proposals for doing said work; plans and specifications of the same first to be placed on file in office of Board, which plans and specifica- tions shall be open to public inspection; advertisement to state work to be done, and to be published ten (10) days at least. The bids shall be sealed bids, directed to Board and accompanied by bonds to the Commonwealth, signed by bidder and two responsible sureties, in sum of two hundred (200) dollars, conditioned he shall do the work if awarded to him, in case of his default to do so, forfeits, etc. Bids to be opened at time and place men- tioned in advertisement. SEC. 14. All contracts shall be awarded to the lowest responsible bid- der, and who sufficiently guarantees to do work under superintendence and to satisfaction of Board ; provided that the contract price does not exceed the estimate or such other sum as shall be satisfactory to Board. Copies of contracts to be filed with State Auditor. SEC. 15. Board reserves right in contracts to decide questions as to proper performance of work and meaning of contracts; in case of improper construction may suspend work and relet the same; or order entire re-con- struction; or may relet to other contractors and settle for work done, etc. In cases where contractor properly does work, Board may in their discre- tion as work progresses, grant to said contractors estimates of amount already earned, reserving 15 per cent, therefrom, which shall entitle holder to receive amount, all other conditions being satisfied. ROADS. 345 SEC. 16. In cass prosecution of any public work be suspended, or bid be deemed excessive, or bidders be not responsible, Board may, with written approval of Governor, where the urgency of the case, or interests of the Commonwealth require it, employ workmen to perform or complete any work ordered by the Legislature, provided that the cost and expense shall in no case exceed the amount appropriated for the same. SEC. 17. All supplies of materials, etc., when costing over five hundred (500) dollars, to be purchased by contract, subject to same conditions as letting out work. SEC. 1 8. Whenever Board thinks necessary, for interests of the Com- monwealth, to protect same from damage or loss, shall report thus to Governor and Council and reasons for same, asking power to give contracts without notice required above, and Governor and Council may grant request, provided three-fourths vote for it. SEC. 19. Whenever Board is of opinion a work may be done better with- out a contract, shall so report to Legislature, and they shall procure mach- inery, materials, etc., hire workmen, etc., to do said work, whenever so authorized by the Legislature. SEC. 20. All contracts and bonds by Board to be in the name of the Commonwealth. SEC. 21. No member of the Board to be interested in any contract; all contracts made with any member interested, Governor may declare void, and shall remove such member so interested from office. It is the duty of every member of the Board and every officer of the Commonwealth to report any such delinquency, if discovered. SEC. 22. Board shall be empowered to employ such engineers, clerks or other assistants, as shall be provided for by the Legislature. SEC. 23. Board shall, on or before eveiy year, submit to the Auditor, by him to be presented to the Legislature with his annual estimate, a statement of the repairs and new work needed for the current year, and of the sums required by the Board therefor; report to be in detail; all sums appropriated therefor to be included in the annual tax- levy. SEC. 24. All moneys to be paid to any person out of moneys so raised, shall be certified by President of Board to Auditor, who shall draw warrant on Treasurer therefor, stating to whom payable, and to what fund charge- able; such warrant to be countersigned by President of Board. SEC. 25. Board to keep accounts, showing moneys received and spent clearly and distinctly, and for what purpose. Accounts to be always open for inspection of Auditor or any committee appointed by the Legislature. NOTE. In the year following the printing of these essays, Massa- chusetts abolished the payment of road taxes in labor. (See Sec. 8 above.) Towns have also been authorized to appoint " superintendents of highways." Other plans for the improvement of common roads are still (1870) a matter of public discussion and agitation. The politic thing to have done in 1870, would have been, plainly, to have recommended the appointment of an expert commission to revise the road laws of the State, and to submit such revision to the Legislature. And such a course remains a desirable one to pursue at the present day in Massachusetts and in other of the States of the Union. PART III. THE ENGINEERING AND BUILDING RECORD'S PRIZE ESSAYS ON ROAD CONSTRUCTION AND MAINTENANCE. INTRODUCTION TO PART III. The following from The Engineering and Building Record of March 29, 1890, refers to the matter found on the following pages : The Competition for Essays on Road Making and Maintenance instituted by Tfa Engineering and Building Record has, like the Competition for Water Tower and Pumping Station designs, proved very successful. The competition closed March i, and the 21 essays received have in the intervening time received the careful considera- tion of the Committee of Award. At a time when there is such a general awakening to the impor- tance of having good roads this valuable contribution to the literature of the subject is most opportune. In addition to the prize essays, which will be published in successive issues of this journal, we are happy to announce a discussion of certain features in the several essays by the Committee of Award, which, in view of the experi- ence of these gentlemen, will add materially to the practical results of this competition. The following is the report of the Committee : To the Editor of THE ENGINEERING AND BUILDING RECORD : The Committee invited by you to award prizes amounting to $150 for Essays on Road Construction and Maintenance have examined the 21 papers submitted to them, and make the award as follows : " CESA." First Prize, $75. S. C. THOMPSON, 832 East One Hundred and Sixty-first Street, New York City. " BONA VIA, BONUM OPUS." Second Prize, $50. I. F. POPE, 905 Brazos Street, Austin, Tex. " A SIMPLE SCRATCH." Third Prize, $25. JOHN P. PRITCHARD, Quincy, Mass. Also as worthy of Honorable Mention, abstracts of each to be published, we would name the following : "GRANITE STATE." PROF. JOHN V. HAZEN, Chandler Scientific School, Hanover, N. H. PALISADES." SAMUEL L. COOPER, Engineer Finance Department, City of New York. " ROY." FRANK B. SANBORN, Brookline, Mass. "ZAMORA." A. T. BYRNE, Civil and Mining Engineer, 361 Fulton Street, Brooklyn, N. Y. As a brief declaration of principles, " TO THE POINT," A. L. PHILLIPS, Pencoyd, Pa., is also worthy of publication. The result of this competition is a matter for congratulation, and the essays are, as a whole, a contribution to the literature on this important subject both valuable and practical. We do not wish, however, to be under- stood as indorsing every proposition made in any one of the papers. At a future time we will submit a brief criticism that we think should go on record with the essays herewith recommended for publication. F. COLLINGWOOD, EDWARD P. NORTH, JAMES OWEN. ROAD CONSTRUCTION AND MAINTENANCE.* BY S. C. THOMPSON (" CESA "), NEW YORK In writing upon this subject, it is the intention of the author to treat the different matters under consideration, so as to present the method of doing the work, and the reasons for it, in a manner to be easily grasped by the popular mind, rather than to collate and arrange information for the professional reader. Commencing with Road Construction it can be divided into first, locating, or laying the road ; second, making the road-bed, which includes all earth-work, drainage, and everything necessary to get the foundation in proper shape ; and third, surfacing, or making the top of the road. Location. First let us see what are the elements which effect the location of a road, and upon what is the location of a road dependent. The problem in its simplest form is, of course, given two or more points to be connected by a road-way, without any limitations whatever, but the usual considerations which determine where a road shall be built are often varied and troublesome. Elements that Determine Location. Taking them in the order which they are likely to occur, we have, first, the amount of money that can be expended, and as a necessary part of this, and largely determined by it; second, the allowable grades, and maximum curves permissible. Select Best Possible Route. When it has been determined to connect two places with a road, the best possible route over which to build the road should be determined, and then the construction should conform as nearly as the contingent circumstances will per- mit to the location laid down. Make the line as nearly straight as practicable, and when changes of line occur connect them by regular curves of proper radius. When the line is intended to be straight make it so absolutely. Curves. Where curves are required make them as flat as pos- sible, and on a first-class road where long trucks or loads are liable to come, only in extreme cases should it exceed a curve of 50 feet radius. * The Engineering and Building Record Competition. First Prize Essay. 35 ROAD CONSTRUCTION AND MAINTENANCE. Minimum Radius to Curve. On mountainous roads it some- times becomes necessary to increase the curve to a radius of 20 feet. Heavy Traffic vs. Passenger Service. In discussing the question of permissible grades it will, perhaps, be best to consider the road- ways as being used for two specific purposes, one, where heavy traffic has to be provided for, and the other where passenger service is of the greatest importance, or, as it might be designated, loads vs. time. In a general way it may be said that when the conditions necessary for the first are complied with, the second are met equally well. To Determine Grades. To determine what grades can be allowed, it becomes necessary to see what difference in results are caused by a difference in inclination. Reduction of Draught by Increase of Inclination. A man can walk up a slope of 100 in 120, and a horse or mule can ascend an incline of 100 in 175, and it has been found by experiment that a horse pulling his maximum load on a level, can pull but ^ as much if the slope is made i in 50, and this gradually lessens until with a slope of i in 10 he can draw but ^ as much as his level load, or to make it more complete, see the following table made from experi- ments by Gayffier * and Parnell f upon French and English roads, the results of the latter being the average of three velocities, calling the load which a horse can draw on a level 100. On a rise of Experiments of Gayffier and Parnell. in 100 a horse can draw only 90* 81* 72 64 541 50 40 30 26 20 10 .40 25' Experiments of Sir Henry Parnell to find Draught Required. And as the capacity for draught is limited by the steepest grade, no slope should be allowed up which a fair load cannot be drawn. The experiments of Sir Henry Parnell show that to draw a stage coach over the same road, having different degrees of inclination, the fol- lowing results were obtained : FORCE OF DRAUGHT REQUIRED. LEVEL ROAD CALLED IOO. Inclination. At 6 miles per hour. At 8 miles per hour. At 10 miles per hour. i in 20 268 296 318 I 26 213 219 225 i " 30 165 196 200 i " 40 IOO 166 172 i "600 III 120 128 ROAD CONSTRUCTION AND MAINTENANCE. 351 No Counter Grades to be Allowed. In laying out a road, with regard to grades, have a continuous inclination in one direction, and do not allow any counter grades, for in ascending, each foot descended on a counter grade, means just so much more rise to be overcome. Divide Roads in Classes According to Grades. Different writers have proposed to divide the roads into classes, and limit the grade for each class. In some cases the grades are fixed by law. The maximum grade established by the French Government Board of Engineers is i in 20.* The Holyhead Road in Wales uses i in 30 as a maximum, except in two cases. The road over the Simplon Pass averages 1.22 on Italian side, and i to 17 on Swiss side, with one case of i to 13, and in this State several turnpike roads are limited by law i in n. HerscheVs Classification of Roads. C. Herschel, M. A. S. C. E., in his prize Essay on the Science of Road-Making, f proposes to divide in three classes viz., State, county and town roads, and limit the inclinations, first, 3 to 5 in 100; second, 5 to 7 in 100; third, 7 to 10 in 100, Prof. S. F. Miller J suggests making them of two classes, the first not to have a gradient of more than i in 20, and the second not to exceed i in 10. Vertical Rise Equivalent to Lengthening Roads A vertical rise is equivalent to an increase in the length of the road proportional to the angle of inclination. Equivalent Length of Level Road; Experiments of Sir John Mac- Neil. The force expended in carrying a given load from any point to another at a higher elevation, is equal to the force of traction together with the force necessary to lift the load to the elevation attained. Experiments made by Sir John MacNeil show that a wagon loaded with six tons, drawn three miles per hour, upon a slope of i to 30, one mile is equivalent to 2.7 level miles, and for a stage coach weighing three tons, drawn six miles per hour, the equivalent level road for one mile is 1.62 miles. On Long Incline Have First Portion Steepest. Where a long incline becomes necessary it will be found economical to make the first portion the steepest and decrease it as it ascends, and if the slope can be varied by occasional level stretches the efficiency of the road will be greatly increased. The road-bed on steep slopes is subject to greater wear from the feet of horses in ascending, and is much more subject to serious erosion by heavy rains. * Gillespie's Roads and Railroads, p. 42. f Report to Massachusetts State Board of Agriculture, 1860-1870. \ Massachusetts State Report, 1860-1870. 35^ ROAD CONSTRUCTION AND MAINTENANCE. Minimum Grade. Where the inclination of the road is not greater than i in 33 it will not pay to materially increase the length to reduce nearer to a level. So far, in treating grades they have been considered^ obstacles to ascent, and we will further consider how they may be obstacles to descent. Experiments of Sir Henry P am ell and Dr. Lardner on Angle of Repose. On a descent the inclination should not exceed the angle of repose for a vehicle, which varies according to the road-bed, from i in 40 to i in 10. On a road with a slope just sufficient so that the force of gravity would overcome the friction, a loaded vehicle would descend with unaccelerated velocity and a considerable speed could safely be maintained in descending. If the inclination is materially steeper than as shown above, so that a speed of only one-half or one-third as much can be safely maintained, it would be equally cheap to have a level road that was twice or three times as long. To Ascertain Angle of Repose. The angle of repose, for any given road-bed, can be easily ascertained from the draught upon a level, with the same character of surface; that is, if the force neces- sary, on a level, to overcome friction is ^ of the load, then the same fraction expresses the angle of repose, for that surface. WIDTH OF ROADS. The proper width of roads and road-beds are matters which ordinarily receive little attention. A road-bed is frequently con- structed so wide as to add so much to the cost of maintenance as to render it impracticable to keep it in proper repair. Revised Statutes of New York Fixing Width of Public Roads. The revised Statutes of New York State require all public roads laid out by the Commissioners of Highways to be not less than three rods wide, and require " all roads that have been used as public highways for 20 years to be opened to two rods at least" English Roads. In England turnpike roads are obliged by statute to be laid out four rods wide, and 22 feet wide to be bedded with stone. Roman Military Roads. The Roman Military Roads were established 12 feet in width when straight, and 16 feet when crooked. Classification by French Engineers. French engineers make four classes of roads : First, 66, 22 stoned ; second, 52, 20 stoned ; third, 33, 16 stoned ; fourth, 26, 16 stoned. In England turnpike roads near towns are 60 feet wide, by-roads 20 feet wide. Holy head Road. The width of the Holyhead Road varies from 32 feet where level to 22 feet in precipitous places. ROAD CONSTRUCTION AND MAINTENANCE. 353 Ffffct of too Wide Roadway. Where the roadway is too wide it usually results in no part being kept in good repair, while if it was narrowed the whole could be kept in first-class condition at less expense, and a well kept road of even 2o-feet width is far preferable to a road but half maintained of double the width. In laying out it may be advisable to take a strip considerably wider than the intended road-bed, so as to provide for possible contingencies in the future when the land becomes more valuable. Lay out sufficiently wide, but build only so much as can be kept in thorough repair. These general rules about what should be done are all well enough in their way, but it will be found much more satisfactory in results to obtain the services of a competent engineer, and let him enter into the details involved in each particular case and decide from the conditions that arise. The judgment and skill introduced in this way will frequently save costly and troublesome mistakes, and leaves nothing to chance or ignorance. (See Appendix i.) ROAD-BED. Requirements of a Good Road-bed. The essential requirements of a good road-bed are, that it shall be practically unyielding smooth on the surface, and impervious to water ; and without these requirements there can be but little durability. General Requisite for Road-beds. Before calling attention to particular kinds of road-bed there are certain requisites apply to all kinds. The first and most important of these is thorough drainage. No matter what the material may be a proper attention given to drainage will be found to be a good investment, both as to first cost and future maintenance. Advantages of Drainage. Some of the advantages of thorough drainage will readily present themselves. In this climate the worst enemies to building, or properly maintaining a road-bed, are water and frost, and if the first is kept out the second will have little or no effect, as the surface will not be effected, and heaving will be reduced to a minimum. Again, if a road-bed is thoroughly drained, it dries much more promptly, and has less mud and less dust. The construction of road-beds may be properly divided into two parts viz.: the foundation and surface. Under the head of foundations is included all necessary sub-drainage works, culverts, ditches, etc. 354 ROAD CONSTRUCTION AND MAINTENANCE. Earth Roads. For earth roads, as commonly built, there is but little to be said, and they should only be tolerated in a new country or where there is absolutely nothing but earth, of which to make a road. Yet with earth alone a very passable road can be made and maintained, if sufficient care is taken to have it thoroughly drained, and the surface of proper shape. The persistent care with which some of the so-called Road- Surveyors, in the country, excavate the material which has washed into the gutters and replace it upon the center of the road, seems to indicate a belief that the powers of man surpass and are superior to those of nature. Cost of Handling Earth, etc. Regarding the cost of handling earthwork of various kinds, many elaborate tables have been com- piled of the cost, the distance to which it can be profitably cast with shovels, how far it can economically be carried in barrows, etc., all of which are of great value to an engineer in the determination of methods of conducting work, and the economy of management, but to the average individual who may be called upon to make or super- vise the making of a road, they are but little better than so much Latin or Greek. Handling Earth with Shovds^etc. The generally accepted rules in handling earth, are: first, with shovels it can be cast horizontally from 5 to 10 feet, and vertically it can be lifted or thrown from 5 to 7 feet, and the cost of moving to the maximum distance either hori- zontally or vertically will be found to be nearly the same. Wheelbarrows. Where wheelbarrows are used, it will be found that they can be economically used up to a distance of perhaps 2.00 feet, but when it becomes necessary to carry to a greater distance than this, it will be better to use carts. Any increase in the inclina- tion of the barrow road will have the effect to decrease the amount of material that can be handled, and an inclination of i in 10 will reduce the load that can be wheeled to two-thirds of what can be handled on a level road. To overcome a vertical rise of 3 feet, will cost as much as wheeling from 80 to 100 feet horizontally. Hauling with Carts. With one-horse carts, it is estimated that one foot vertical costs as much as 14 feet horizontal. Time Required for Dumping. For a long haul it will be found that two-horse carts are much more economical than single carts ; and dumping carts in every way preferable to the much used pole- bottomed carts or Studebaeker wagons employed in the vicinity of New York. A series of observations were made by the writer upon the relative time required to dump a load and get away, with the two kinds of carts. ROAD CONSTRUCTION AND MAINTENANCE. 355 The time was taken when the team was stopped on the dump, and when the driver started to drive away ; and it was found that with the dump cart the average time for dumping and getting away was three-quarters of a minute, while with the other kind it averaged about three and one-half minutes. Shrinkage of Earth. In determining the amount necessary to make a specified embankment, the shrinkage of the material used should be carefully considered, as it will be found to vary from 8 to 15 per cent., according to the nature of the material, gravel and sand shrinking the least and clay the most, the latter sometimes reaching 25 per cent. *Gillespie gives an easy approximate rule for determining the cost of moving, with single carts, one cubic yard of earth any dis- tance, on a level, deduced from the formulas of Ellwood Morris, C. E. (See Journal of the Franklin Institute, Sept., 1841.) Gillespie's Rule for Cost of Moving Earth. For 300 feet -5- wages of cart and driver by 24 500 " " * " 19 " 1,000 " " " " 12 " 1,500 " " " " 9 *' 2,500 ' " " " 6 " 3,000 " " .'*.. 5 The proportional expense of carrying long distances will be found to be less than short distances, as less time is lost is filling and dumping. Drainage. Drainage for a road should be of two kinds, sur- face and sub-drainage. The first provides for the speedy removal of surface water or rain-fall on the surface, and the second for the removal of water which penetrates beneath the surface, and into the body of the road covering. Effect of Perfect Sub-drainage. As a result of perfect sub- drainage, there is little or no effect from frost, and the surface and body of the road does not become softened and destroyed in sum- mer. Surface Drainage. For surface drainage, ditches should be provided along each side of the road having sufficient fall to promptly carry away any water that reaches them. Where it becomes necessary to carry the water across the roadway culverts should be provided. All drains should have a continuous fall throughout their entire length, and the size will depend upon the inclination and the amount of water they are expected to carry. * Roads and Railroads, p. 131. ROAD CONSTRUCTION AND MAINTENANCE. The amount of rain-fall over the area to be provided for is an important element in deciding upon the sizes required. For Central Park provision was made for a rain-fall of two inches per hour over the entire surface, but this is largely in excess of the usual require- ments. ROAD SURFACES. Kinds of Road Surfaces. These may be divided into Gravel, McAdam, Telford, and the pavements of various kinds, such as granite, wood, asphalt, brick, etc. Gravel Roads. In portions of the country where gravel is easily obtainable, a very satisfactory road can be made by making the sur- face for a greater or less depth of gravel. Manner of Construction. Prepare the foundation so as to allow for prompt drainage, and shape as the finished road is intended to be; make the sides of the road planes, and not curves, and then roll thoroughly to get a solid foundation. Put on a layer of gravel from 6 inches to 8 inches in thickness, sprinkle thoroughly and roll till very compact and firm. Next spread another layer from 4 inches to 6 inches of gravel, and sprinkle and roll till the desired hardness and smoothness are obtained. Use Binding Material if Necessary. If the gravel has no bind- ing material in it, a sufficient amount may be incorporated in the last layer to cause it to take a good bond. Hard Pan and Bank Gravel. Where it is possible to get blue gravel or hard pan and clean bank gravel, the two can be so mixed as to give a surface almost like concrete in hardness. When the two are used together a two-horse grooved roller for the first layer will be found very effective, and the material should be quite wet while rolling. The surface can then be finished with a steam roller, or with a smooth roller, sufficiently loaded to give the requisite weight. Weight of Roller. In completing the surface of a gravel, or other road, where rolling is required, the weight of the roller should be as much per inch as the weight per inch on the tire of the heaviest vehicle likely to pass over it. For ordinary traffic a very durable and economical surface can be produced in this way. GRAVEL SURFACE WITH RUBBLE FOUNDATION. Gravel and Rubble. There are in the vicinity of New York City -nany very good examples of the above named road viz.: in Central Park, also Avenue St. Nicholas from One Hundred and Tenth Street northward, and others. ROAD CONSTRUCTION AND MAINTENANCE. 357 Avenue St. Nicholas. -The method of constructing this latter road* will perhaps furnish as good an illustration as can be readily found. On the prepared road-bed, which was made of the same shape as the finished surface, and well rolled, was placed rubble stone not exceeding 9 inches in the greatest dimension, and most of them less. These stones were placed as uniform as possible and closely covered the surface. On top of this was placed a light layer of quarry chips which was than rolled with a 6^-ton roller till the spawls were well compacted and wedged into the interstices of the rubble foundation. On this was spread a light layer of gravelly earth or hard pan, moistened by sprinkling carts, and then rolled to fill all spaces. The gravel was applied in two layers, all of the large stone raked out, and the whole kept moistened while rolling. Care was taken not to have it too wet. The first layer was thoroughly rolled before applying the second. Grant on Gravel Roads. Before the roller was put on the top layer a light coat of gravelly loam or hard pan about one-fifth the bulk of the gravel was thoroughly mixed in, by raking, until well incorporated with the gravel. A thorough rolling completed the process, and the roller could be used occasionally to good advantage after the road was open to travel. W. H. Grant, M. A. S. C. E., who had an extensive experience in building gravel and McAdam roads, says, " It is believed that gravel roads, constructed with either rubble or Telford foundations, are better suited for light and pleasure travel, are more agreeable for carriages and horses, less difficult and expensive to maintain, require less attention in water- ing, and raise less dust than roads finished with McAdam surface." Cross Section of Roadway. The top surface of all roads should have, in addition to the gradient, a side slope from the center, vary- ing according to the hardness of the surface. In a general way, whenever it is practicable, the side slope of the road should equal or exceed the longitudinal gradient, so that the water passing over the surface may take a course to reach the gutter not sharper than 45 degrees with the center line. In some of the smaller German States, where road-making and maintenance has been reduced to more of a science than with us, they allow the rise at the center from T 1 ^ to ^ of the width of the road. Rise of Road-bed in Germany and Prussia. In Prussia the side slope is prescribed and bears a certain relation to the gradients of the roads, varying from ^ in roads falling more than 4 in 100, to i in 12 for roads falling less than 2 in 100. *See first Report of the Commissioners of Public Works. 3^8 ROAD CONSTRUCTION AND MAINTENANCE. MC ADAM SURFACE. McAdam, from whom the road so called takes its name, main- tained that the foundation of the road should not be of large stone at all, nor should it of necessity be of an unyielding nature, and he made the comparative cost of maintaining a road with a road-bed of solid rock and one having a soft soil or morass for foundation, as 7 to 5. Size of Stone as Fixedly McAdam. McAdam maintained stren- uously that a stone over one inch in diameter was determined in a road, as it had a tendency to tip when a wheel came on it, and thus moved the adjacent material ; he afterward substituted weight for size and made 6 ounces the maximum stone that was to be used. He has a considerable following among the French and English engineers, but in this country the Telford foundation is generally preferred. ParnelVs Specifications. The specifications for Telford, as given by Parnell's Treatise, London, 1833, give the following directions: Prepare the road-bed of the required shape, and on this set stones by hand, to form a close pavement. Set the stones carefully on their broadest edge, lengthwise across the road, the upper faces not to be more than four inches in breadth. Break off all irregulari- ties with a hammer, and fill all interstices with stone chips, well rammed in between the larger pieces, to make a compact mass. On this place a layer of stone as nearly cubical in form as prac- ticable and about 2^2 inches in diameter to a depth of 4 inches, and then 2 inches more to be added as a second layer, and finally the whole to be covered with i^ inches of gravel, free from clay or earth. Binding Material Detrimental. Parnell says that the presence of binding material on a new road is a positive detriment, as it pre- vents solidity by getting between the stones. The custom to-day is much as he prescribes, excepting some improvements or modifica- tions. Neither McAdam nor Telford used rollers. The Use of Rollers. The use of rollers in road making, which is now considered a necessity, was brought prominently before Eng- lish readers by a paper written by Sir John Burgoyne in 1843. He recommended as the greatest attainable weight 261 pounds per inch of roller. (See Appendix.) There are three types of McAdam road, as given by him traf- fic made, and horse and steam-rolled. With a horse roller it is extremely difficult to compact hard stone without binding, and no steam roller is heavy enough to com- pact trap or granite without binding. ROAD CONSTRUCTION AND MAINTENANCE. 359 Horse vs. Steam Roller. The horse roller will make a better road than can be made by traffic, but this is very much inferior to a steam roller with the maximum weight per inch of roller. Where the surface is rolled with a sufficiently heavy horse roller it is cut up badly by horses' feet, and then the admixture of manure and dirt prevents a thorough bonding and compacting of the surface. The steam roller, in addition to being heavier, does not cut up the surface and allows a harder binding to be used, and the action of the roll has a tendency to arrange the stone more compactly than would be done by weight alone. Southern Boulevard. About New York City are many good examples of Telford and McAdam pavement, and considering the surface rendered, none perhaps more worthy of mention than the Southern Boulevard constructed by W. E. Worthen, M. A. S. C. E., commencing at Third Avenue and running easterly and northerly from the north side of Harlem River through the annexed district. Manner of Building. In constructing it, the earth was first rolled thoroughly, and then two layers of 2|-inch trap rock, the first 6 inches in thickness and the last 4 inches in thickness, placed upon it ; these were thoroughly rolled with a two-horse roller, and then 2\ inches of screening were spread over the surface and well rolled. The screenings were applied very wet. The road had a very steady, and much of it heavy, traffic, yet it remained in very good condition for quite a number of years with trifling repairs. As long as the surface of a roadway of this kind remains unbroken it stands very well ; but, as is the case at present with the Southern Boulevard, it has been partially excavated to make place for a railroad, and the material has never been gotten back as com- pactly as before, and the road has been badly used up. Road Built by E. P. North, M. A. S. C. ". A road built by E. P. North, M. A. S. C. E., was composed of 2-inch stones in layers 6 inches in thickness, rolled with a roller 6 feet in length, weighing two tons when unloaded and three and a half tons with a load, and drawn by four or six horses. Special attention was paid to get the stone as free from dirt, etc., as possible, and for this purpose it was handled with ten-tined forks, which allowed most of the finer portion to drop through, thus leaving the stone clean. The layers were thoroughly rolled, and then the dust and small stones were spread and rolled in, and finally about f -inch of clayey earth was spread on top and the whole thoroughly rolled, the roller passing 144 times over the surface. The roller used weighed from 75 to 100 pounds per inch of roll, but he considers them too light to be economical. (See Appendix, 2.) 360 ROAD CONSTRUCTION AND MAINTENANCE. The Glasgow and Carlisle Road. The Glasgow and Carlisle Road was built with the roadway 18 feet in width and a crown of 4 inches in the center. Metaling was put on the road in two layers. The bottom course was 7 inches in depth, placed with the broad end down and the top surface not over 3 inches in diameter ; the bottom stones were carefully placed, breaking joints as far as possible, then the top spaces were filled with smaller stones, packed in by hand and securely wedged. The top layer was composed of stone broken to pass through a 2|-inch ring, spread and thoroughly compacted, and then covered with one inch of gravel. There was a drain from the bottom course every hundred yards. The drains were carried clear across the road and into water courses at the outside. After this road was completed and in use for a while, it was found that the repairs necessary required from 80 to 120 cubic yards of material per annum, per mile. Me Adam Center on Earth Roads. In constructing roadways having a portion only macadamized it will be found of great benefit in rolling to lap the roller on to the edge of the earth portion and thus compact the earth so as to give a suitable shoulder to help hold the metaling, then continue the rolling toward the center. Thickness of Roads. The thickness necessa^ for a good road- bed is given differently by different authorities. McAdam advocated 7 to 10 inches and considered the last ample for any service, but the custom in this country for heavy traffic is to make the thickness not less than 12 inches, though some roads have been built in Bridge- port, Conn., which have been made considerably less in thickness, and so far have reflected great credit upon the engineer in charge, by their thorough construction. Where the traffic is so heavy that McAdam or Telford are not economical, it becomes necessary to use some kind of pavement. The more common kinds are granite or trap-block, wood, brick and asphalt. GRANITE OR TRAP-BLOCK PAVEMENT. These blocks, with various modifications for foundations, con- stitute the principal pavement in this country for exceedingly heavy traffic, and are durable, fairly smooth, and easily laid. Size of Stones. The general requirements for the laying of pavement in New York City are the stones may vary from 7 to 9 inches in depth, 8 to 12 inches in length, and from 3^ to 4^ inches in thickness, and nearly rectangular in shape. The road-bed is prepared by excavating to a depth sufficient to give a good sand bed, usually from 3 to 5 inches in thickness. ROAD CONSTRUCTION AND MAINTENANCE. 361 The sand must be clean and sharp, without too large an admix- ture of large stone, that is one inch or over. The preparation of the road-bed must be made without plow- ing, and it is thoroughly rolled if required with a steam roller weighing not less than ten tons. After the road-bed is prepared, the sand is placed thereon, and bond stones set at the proper places, giving a crown of 6 to 8 inches to the roadway, according to the width. The blocks are laid at right angles to the street, allowing one inch joint. The whole surface is then covered with sand which is swept into the joints as the work progresses. Ramming. The rammers follow after, and with pinch bars adjust the stones to give fair and even joints, and then ram thoroughly, after which the sand is again strewn over the surface, and brushed into the joints. (See Appendix.) Various Foundations. Different foundations are sometimes used, such as concrete, etc., and the joints run full of cement or mastic of some kind ; the latter method makes a surface practically impervious to water, and wears very satisfactorily. Where a sufficiently rigid system of inspection, over opening the streets for connections with water, gas or steam pipes, and sewers is maintained, this block pavement stands the heaviest traffic as well as anything in use. WOODEN PAVEMENT. Wooden pavement has been tried quite extensively in the different cities of this country, but so far have not proved an unqualified success. Advantages. The advantages of a wooden pavement are slight resistance to draught, noiselessness, easily cleaned they cause less wear and tear on vehicles are pleasant to ride over, and the first cost is less than stone blocks. Objections. The objections are slipperiness in wet weather,, non-durability, both from wear and decay, and there have been found serious objections to them on sanitary grounds. Still where the foundations are properly made and drained, and the block treated so as to prevent rapid decay by any of the various processes, and especially where stone blocks are not easily available, they have proven a very satisfactory improvement in the character of the roadway. Manner of Laying. The various methods of laying will only be outlined, and a reference to the requirements for laying on the Strand, in London, will perhaps give the most modern and satisfac- tory practice. 362 ROAD CONSTRUCTION AND MAINTENANCE. Requirements for the Strand Pavement in London. The exca- vation for the roadway is carried to a depth of 15 inches and a layer of Portland cement concrete 9 inches in thickness placed thereon and shaped to conform to the finished surface of the road. Concrete is composed of seven parts of stone, etc., to one barrel of cement. The top is floated on to the required shape and then the blocks of best Baltic redwood, or equally good timber, creosoted and placed endwise upon the concrete. The joints between the blocks are then run with cement grout or hot bituminous mastic. Cement grout is composed of one part cement and three parts sand. The top of the pavement is then covered with a layer of sand or gravel and opened to traffic. (See Appendix.) BRICK PAVEMENT. In certain portions of this country brick has been used as a pavement and found to answer the requirements fairly well. Brick Pavement in JDes Moines, Iowa. In Des Moines, Iowa, there are about ten miles of streets paved with this material, and they are proving quite satisfactory. The method of laying is to surface the road according to plan, then to roll with a roller weighing 150 pounds to the inch, or ram with rammers weighing 81 pounds. In embankment the layers are made 9 inches in thickness and thoroughly rolled or rammed. On the foundation as prepared is spread a layer of sand 3 inches in thickness, and on this the bricks, which are specially burned for the purpose, are laid flat, breaking joints in the laying. The joints are completely filled with sand and on top a ^course of sand i inch thick is spread. The next course of brick is laid on edge, and the joints thor- oughly filled with sand, then one inch of sand is spread over the top and it is ready for traffic. Brick used for the same purpose have been used in West Virginia and have proven satisfactory. ASPHALT PAVEMENT. Until quite recently asphalt has been used but little as a pave- ment for roadways in this country, and the climatic conditions are so different from France and England that at present it is a little problematical just how far, and under what conditions, it will prove successful when used alone. Many of the pavements laid with it in Paris and London have proven very satisfactory, and some work has been done with the pavement in this country, but with the extremes of temperature from 10 degrees to no degrees in this climate, it will give the pave- ment a very severe trial, unlike anything it is called upon to undergo in either England or France. ROAD CONSTRUCTION AND MAINTENANCE. 363 Some of the pavement already laid in this country has seemed to prove fairly satisfactory, as in Boston and in Washington, but in many cases, under a severe traffic, it has been found wanting. When used in combination with other material it has proven a very valuable adjunct, but with the limited information available and the comparatively short time it has been in use, the writer is not prepared to give an unqualified indorsement to its use in this country, or at least in this portion of it. Constant Attention Required to Keep Surface in Good Condition. Having obtained a smooth, properly compacted surface on a road, it should always thereafter be maintained in first-class condition ; but it will be found that this can only be done by constant vigilance and attention. Repairing roads is not unlike a fire just starting a very little properly directed effort will stop it; and with great force it applies to a road when the surface begins to get in bad condition. In speaking of repairing roads we shall confine our attention to roads having an earth, gravel or macadam surface, as repairs on pavements need no description here. On earth or gravel roads a veiy effective and economical instru- ment to help keep the surface in condition, is what is described by E. P. North, M. A. S. C. E. (see Trans. A. S. C. E., May, 1879), as a hone. The Hone or Scraper. This is made of various shapes and sizes, but in a general way consists of a timber, or heavy plank, faced on one side with a steel plate to prevent rapid wear, and pro- vided with handles on the back to guide it, when being drawn along the road surface. It is attached to the team in such a manner as to draw at an angle with the line of the road, and is very effective in filling ruts, and removing small stones from the surface of the road- way. This is best used while the road is somewhat softened by rain. To Keep a Road in Good Condition. To keep a road in good condition there should be no ruts ; and to prevent ruts, it becomes necessary to prevent any accumulation of mud or dust. If ruts are formed water collects, and the adjoining material becomes softened and more easily cut up and the drainage much increased. Secret of Successful Road Repairs. Here we have the secret of successful road repairs viz.: continual repairs. Keep the dust swept from the road, the ruts filled up with suitable material, and the surface of the road will keep in good order. If repairs are not continually made there can be no constant good road. 364 ROAD CONSTRUCTION AND MAINTENANCE. Sprinkle During Dry Weather. When a long continued dry spell occurs it will be found economical as well as effective, in pre- venting excessive wear on a road, to sprinkle frequently. Tresaquet, a French engineer, was the first to call attention to the continuous system of repairs, and it was adopted in Baden in 1845, and it has extended over nearly all European countries. Amount of Material and Cost in Baden, 1845-1860. In tables giving the amount of material used in making repairs previous to 1845, and subsequent to that time, it was shown that in 1832, 218.6 cubic yards of material were used per mile for repairs, white from 1855 to 1860 there was only about 90 cubic yards per mile required, and the cost of maintenance was reduced during the same period about 40 per cent. Statements of French Engineers. The statements of Gen. John F. Burgoyne, taken from the reports of French engineers, show equally good results from the continuous method of repairing, giv- ing better roads at a reduction in the cost of maintenance of from 12 to 40 per cent. At the time these statements were made French engineers calculated that by maintaining the roads in the best possible condition, the cost of draught of merchandise over the roads in France might be reduced one-third, or about $30,000,000 saved to the public in one year. Repairing on the Continuous System. The method of repairing roads on the continuous system can be briefly outlined as follows: Have the material for road covering deposited at convenient intervals along the' side of the road, from 200 to 300 feet apart. Have a man detailed to look after the repairs of the road for every two or three miles, and let his sole duty be to keep his section in repair. The tools necessary for him to have will be a broom, hoe, shovel, rammer, wheelbarrow and water pot. Duties. He should keep all dust swept from the road in dry weather, remove all mud in wet weather, see that the surface drain- age is maintained, and if there is any standing water on the road sweep it off and fill up the depressions. The covering which wears off should be replaced gradually, and the best time to replace metaling is during wet weather. Where there are ruts they should be thoroughly swept out to free from dust or mud, and then fill up with the prepared material. Repairing. If large breaks take place they should be brought up gradually, especial care being, taken not to produce surfaces which will be avoided by the vehicles passing over, and proper attention should be given to make the new work bind to the old as promptly and completely as possible. The quantity of macadam necessary to keep a road in proper condition varies according to ROAD CONSTRUCTION AND MAINTENANCE. 365 the traffic and the quality of the material used, but the following table gives perhaps as fair -inch) Good Cobble-stone (3^-inch) s }C Trot Pace Kossack Kossack Good Carriage with Springs Macadam little used -SO A Pace Kossack Morin fifed Macadam ... A- Pace Gordon Old Macadam .... o 1 * Navier Ordinary Macadam 1 Trot ( MacNeil Ordinary Macadam 2 Pace j Perdon't Good Macadam (wet and slightly muddy) i - *V ( Kossack Morin Best French Macadam * Navier Very hard and smooth Macadam * MacNeil Best Macadam JL Tiot Rumford Best Macadam 2 Pace Rum ford Best Macadam A-\V Gordon Best Macadam S-X Morin Ordinary Stone Block fcV ( Perdon't j Poncelet Ordinary Belgian Block JU Pace ( Minard MacNeil Good Stone Block 2 Trot Rumford Good Stone Block X Pace Rumford Belgian Block, Boulevard, Paris.. A.V Navier Good Belgian Block i Trot Rumford Good Belgian Block S Pace Rumford Good London Block 65 Gordon Well laid Belgian Block X MacNeil Good Belgian Block A-A Morin Planked Roadway (bridge) X-S Morin Asphalt Gordon Granite Tramway T F Gordon Iron Tramway TS Gordon Sleighs on snow, 3 inches thick, % -inch runners, temperature 26 A 374 ROAD CONSTRUCTION AND MAINTENANCE. ROAD CONSTRUCTION* BY I. F. POPE (" BONA VIA, BONUM OPUS "), AUSTIN, TEXAS. General Remarks. The construction of country roads may be divided into three parts, i. The alignment. 2. The earthwork, or formation of the road-bed. 3. The metaling, or formation of the hard road surface. Width of Road. Before, however, any of these can be under- taken, the width of the proposed road must be determined. Any excess width beyond the requirements of traffic is a waste of money. As two vehicles can conveniently pass one another in a width of 18 feet, the metaled or hard central surface should be made that breadth. Provision must also be made for foot passengers, and for a softer footing for horses during dry weather than the hard central surface. An earthen surface eight feet in width on each side of the central metal surface will answer both these purposes. The use of this less expensively constructed surface during dry weather will also be economical, as it will save the wear of the more costly metaled surface. For all these reasons combined, the width of a country road should be as follows : A central macadamized or metaled width of 18 feet, with earthen sides 8 feet broad on each side; or a total width for traffic of 34 feet, raised, for drainage purposes (except where in cutting) not less than six inches above the level of the area it passes over. There should also be an earthen berm 8 feet broad on each side of the raised road for trees and for stacking the metal required for repairing the road. The total width of land, therefore, that should be reserved for road purposes, including the tree berms and side trenches, should not as a rule be under 66 feet, or 4 rods. Where high embankments are necessary, a greater width may be required. The following notes on road making will refer to a road of the width or dimensions just described. THE ALIGNMENT. Alignment of Road. Having determined the points or places to be connected by a road, the country along the proposed line should be reconnoitered, and the general route of the road located by one or more reconnoissances. Great discernment is requisite in this preliminary alignment, so as to combine shortness of route with the avoidance of swamps that would entail an unreasonable cost in securing a good road-bed, and hills that might entail either steep gradients or heavy cost in deep cuttings. It should be remembered that in many cases it is of no greater length to go round a hill than * The Engineering and Building Record Competition. Second Prize Essay. ROAD CONSTRUCTION AND MAINTENANCE. 375 to go over it, thus securing both greater economy of construction and easier gradients. Location of Ri>ad. The preliminary route being thus determined, it must now be surveyed with transit and level, and the final align- ment located along the selected line. It is of course expected that the person who undertakes the construction of a road has a thorough knowledge of the use of the transit and level, and the laying out of lines and curves and gradients. Steepness of Gradients. In laying out a road the gradients or longitudinal slope of the road should not be permitted, under ordinary circumstances, to exceed 3 feet vertical to 100 feet hori- zontal. Under exceptional circumstances 5 feet in 100 feet may be tolerated. A gradient steeper than 3 per cent, is an evil that should be avoided if it possibly can. In hilly country a gradient as steep as 5 per cent, is a'c times necessary, but endeavors should be made by judicious alignment to make the gradients as easy as possible. The powers of traction of a horse are much strained by gradients above 3 per cent. It would be far preferable, in many instances, to incur extra expenditure in keeping the gradient within this limit than to make the rate of ascent steeper, as the cost once incurred is incurred for all time ; whereas, a steep gradient is for ever a tax on the power of the draught animals, on the harness, and on the vehicles, and, in a short time, the loss due to this tax will greatly overbalance the saving effected by the steeper gradient. A young engineer may pride himself on the straightness of his road, but if this straightness is obtained at the expense of easy gradients, that might have been attained by slight deflections and curves here and there, his straightness and pride will prove very expensive to the traveling community that uses his road. Let it then be remembered that directness of route and easy gradients must both control the alignment of the road, and that anything above 3 per cent, may be called steep ; though, as I have said, in hilly country it may be necessary to go as high as 5 per cent, gradients On Road Gradients. If the natural surface of the country through which the road passes has a natural rise or fall of less than \Y<2 feet per cent, the longitudinal run of the road surface may be kept parallel to this natural surface ; though, at the same time, 6 inches above it. But if the natural surface of the country rises now and again above the grade of i% per cent, moderate cuttings and fillings up to 3 feet in depth or height may be resorted to if such will keep the gradients within the limit of i*A per cent.; more especially if the cuttings will balance the fillings without an un- reasonable length of haulage. At 3 per cent, grades the line of toleration should be drawn, and unless serious obstacles present 37$ ROAD CONSTRUCTION AND MAINTENANCE. themselves, such as would give an undue height of cutting or em- bankment, endeavors should be made, by judicious cuts and fills, not to exceed a 3 per cent, grade. Gradients in Hilly Country. In a hilly country, by going around a hill instead of over it, an easy gradient may at times be obtained without unduly increasing the length of the road, or it may be ad- visable to ascend the hill by a zigzag route, as represented by the capital letter S. But in whatever way it may be most advantageously done, the limit of gradient should should not exceed 5 per cent. Easy gradients permit the full utilization of the traction powers of a horse, steep gradients detract from it. A gradient as high as 3 per cent, may be tolerated, when, as I have said, undue depth of cut or height of embankment will result ; but gradients of 5 per cent, should only be permitted where great extra cost or great extra length of road would result by adopting a lower gradient. THE EARTHWORK OR FORMATION OF THE ROAD-BED. Formation of Road-Bed. The road being now aligned and its gradients fixed, the earthen surface or road-bed has now to be con- structed. The width of this to be, as already stated, 34 feet. Usefulness of Side Ditches. Where the surface of the country has natural easy gradients, the road-bed should be raised six inches above it (as shown in the diagram), to keep the road dry. This raising of the road also effects the double object of forming a drain- age ditch on each side to carry off the rain-fall to the nearest culvert or bridge. These ditches, from which the earth is excavated to form the raised road-bed, give an increased artificial height to the road to aid its subsoil drainage, and to prevent any tendency of its becoming sodden during a long continuance of wet weather. Description of General Cross Section of Road in Embankment. The cross section then of the earthen surface of the road, where it needs no action to improve on the natural easy gradient of the country, will be as follows : Vertical scale of 2 feet, and horizontal scale of 12 feet to an inch. v/epe of 6 "Vertical fromdfoB i ' 7V Jlopt of rood surface irf/f MUJ if aloiif one r'trfA in J ft. CROSS SecTiON OF ROAD To obtain the earth for raising the road-bed as above, the side ditches will have to be dug 7 feet broad at top, i foot at bottom, and 2 feet deep, with side slopes of ij^ feet horizontal to i foot vertical. This size trench will take up the balance of the 66 feet reserved for ROAD CONSTRUCTION AND MAINTENANCE. 377 road purposes. The side trenches, which appear rather deep, will soon silt up somewhat. In no case is the earth for raising the road to be taken from the 8 feet berm reserved for trees, as this will make these berms lower than the surrounding country. All the earth required for the road must be taken outside the 8 feet berm. Road in Marshy Land. In low, marshy land, the height of the road-bed should not be under i^ feet above the water line. Side Slopes of Embankments, How Graded. Where embank- ments are necessary, the side slopes of these embankments, if in ordinary soil, must be in the proportion of i> feet horizontal to i foot vertical, as shown in the diagram. Thus, an embankment 3 feet high, would have its toe 4^ feet beyond the vertical line of the edge of the 34 feet road surface. If 6 feet high, the toe would be 9 feet beyond ; and so on ; always adding half the height to the total height to find the spread of the toe of the embankment. In constructing embankments, all large clods of earth should be broken up, as otherwise, where these accumulate, depressions or hollows will form in the road surface when the embankment settles. Extra Allowance for Settlement to be Made in Constructing High Embankments. An extra allowance of from one to two inches (according to the nature of the soil) per foot of height of embank- ment must be made while under construction, so that when settle- ment occurs the embankment will have the full height originally intended, metal 6 inches thick. Of FOUK FEET EMBANKMENT Road in Cutting. Where the road, to obtain a proper gradient, is in cutting or excavated, the section of it will be as follows : The slope of the sides of the cutting to be according to the nature of the soil, from i^ feet horizontal to i foot vertical in ordinary soil, to almost perpendicular when in rock. The side gutters to be 3 feet broad at top, and i to i \ feet deep, with side slopes of i \ horizontal to i vertical. If the cutting be of short length or in rock the gut- ters may be proportionately reduced in size. Road Along Face of Hill. Where the road is in sloping or sidelong ground, as when it runs along the face or side of a hill, the 378 ROAD CONSTRUCTION AND MAINTENANCE. most economical form of construction is to have the cuts and fills of the cross-section to balance one another. To effect this more of the width of the road will be in cutting than in embankment, owing both to the gutter and to the contents of the embankment portion being of greater area than that of the cutting. The drainage slope of the road surface to be made towards the hill side and the water thus not permitted to run over the edge of the embanked portion. The fall or slope of the road surface from the edge of the embankment to the gutter on the inner or hill side will be i foot. The gutter to be 3 feet wide at top and i foot deep, with side slopes of i| to i. CROSS SC.CTIOM Of ROAD o/v Tr F*ct or*M/tj~OAjiSioc (.0*6- Catch-water Drain. In addition to the gutter on the inner side of the road another gutter or catch-water drain should be made on the upper side of the hill above the road and at least six feet from the edge of the cutting, to receive and carry off the drainage of the face of the hill above the road. These catch-water drains should be continued to the culverts that should be constructed wherever there is a necessity for cross-drainage, to relieve both the road gutter and catch-water drain from an accumulation of water. DRAINAGE. Drainage of Road. The manner of draining the 66 feet or greater area, reserved for road purposes, should be under advise- ment at the same time as the grading of the road is under consider- ation. In fact, the forming of the road embankment may be said to be the same as forming the trenches for draining the area re- served for the road. The proper drainage of the area within the road reservation is most important for securing a good road ; as all water permitted to lodge within this area will tend to sodden the road and render it incapable, unless by extra labor and expenditure, of bearing a heavily laden wagon. Trenches of sufficient depth and capacity should, therefore, be formed to carry off all water from the road reservation to the nearest culvert or bridge. Those latter should be provided at all points where the cross drainage of the country impinges on the line of road. It is in the long run cheaper to build a culvert to carry off this water than incur the expenditure that will be necessary to keep the road in good order, where water is allowed to lie and soak into the road by capillary attraction. I have noticed the defective want of small culverts even on otherwise well constructed railroads, causing the labor of fre- ROAD CONSTRUCTION AND MAINTENANCE. 379 quently lifting the rails to bring the iron-way to a proper level ; this sinking being due to the softness of the earthen road-bed from the lodgment of water. The capacities of all culverts and bridges should be mathematically calculated to carry off all the water that impinges on the line of road. As instructions on the calculation of water-ways, and the designing of bridges and culverts, are outside the scope of this article, information on these should be obtained from treatises on these subjects. Any ordinary engineer by the use of a leveling instrument can give levels for the flow of water along a given line. The defective drainage of a road can consequently be only due to the want of knowledge of the value of efficient drain- age to the well-being of a road. THK METALING OR FORMATION OF A HARD ROAD SURFACE. The Metaled Surface to be 18 Feet Wide. As has been already stated an 1 8-foot width of metaling will suffice for the requirements of traffic on a country road. In the immediate vicinity of a large city, that is. for a mile or two out, accommodation may be necessary for the simultaneous passage of three vehicles. In such case the metaled surface should be made 25 feet broad and the earthen sides each 10 feet. The Tel ford System of Providing a Hard Road-bed. There are two systems in use in the formation of a hard surface to meet the requirements of heavy traffic on country roads viz.: the Telford and the Macadam. The former consists of a rough pavement of more or less large flat rocks, varying in thickness from 6 to 12 inches, as a foundation to receive an uper coat of broken stone, 6 inches to 12 inches in thickness, which forms the road surface. The Macadam System. The Macadam system dispenses alto- gether with the foundation or rough pavement base, and places the broken stone, varying from 6 to 9 inches in thickness, immediately on the prepared earthen surface of the road. The Telford system may therefore be said to be the Macadam system with a foundation or hard base added. My own experience in India, in the Public Works Department of the Government, for whom I constructed over 400 miles of country road, and superintended the repair and main- tenance at various times of over 1,500 miles of roads, is entirely in favor of the Macadam system, without the addition of a base. Where the method of constructing the earthen road-bed, as described by me, is properly carried out, the addition of a rock base under the macadamizing" material is a useless waste of money. Where the road-bed is below the level of the country, and imperfectly drained, the Telford system may be necessary; but with the efficient drainage advocated by me, and the manner of laying the metal or 380 ROAD CONSTRUCTION AND MAINTENANCE. macadamizing matter, carried out in the manner to be described hereafter, no base is necessary. It is more economical to expend a few hundred dollars per mile in securing efficient drainage in the original construction of a road than as many thousands in a rock base. I see that the Macadam system, in opposition to the double or Telford system, has also been introduced into America with good result by Mr. Pierce, of Bridgeport, Conn. I am somewhat of the opinion of those who maintain that the broken stone or road surface material is more crushed and worn when between the hard, unyielding rock base below, and the heavy hammering weight of a horse and heavily laden wagon above, than where it rests on a more elastic earthen base, which is yet hard enough, by previous rolling with a 15-ton roller, to bear the weight of the traffic borne over it. The material to be used to form the macadamized or metaled surface of the road will depend on what is locally obtainable suitable for such purpose. In some localities it is trap rock, in others lime- stone, etc. Again, on the prairie lands of Minnesota, Iowa, and parts of other States, there are no large masses of rock. In these gravel can be used as a substitute for stone. I have used broken stone, Kunker, a formation of limestone found in large quantities in India, gravel, and even coarse sand when nothing better was pro- curable at a reasonable cost. I will describe, seriatim, the best method, as it appears to me, for consolidating all these (Kunker excepted, which is not found in America), so as to form a hard surface suitable for traffic. The Proper Thickness of Metaling. It becomes now necessary to determine the thickness of metaling requisite to form the ma- cadamized road surface. Various thicknesses have been used and have their advocates, of from 4 to 12 inches. The latter is, in my experience, excessive, and the former deficient. A 4-inch coat requiries constant supervision and expenditure in repairs to keep heavy traffic from breaking through so thin a crust when in any way worn. More frequent renewals are also necessary, causing both inconvenience to traffic and extra expenditure in supervision, labor, and rolling to lay a fresh coat of material. From my experi- ence, I would say, a golden mean between excess and deficiency is arrived at by making the thickness 7 inches when spread, reduced by consolidation to a little over 6 inches. Broken Stone Its Quality and Size. The hardest stone or rock locally procurable, or obtainable elsewhere at a reasonable cost, to be selected to form the macadamized or metaled surface of the road. This to be broken so that the pieces will pass through a ring if inches in diameter. This is the easiest and most practical way of testing the size of the pieces. ROAD CONSTRUCTION AND MAINTENANCE. 381 Slope of Cross Section of Metaled Surface, How Formed. There are two methods in vogue in giving the requisite slope to the cross section of the metaled surface of the road to pass off the rain- fall. In the one, the earthen surface is made level and the slope is given by a greater thickness of metaling at the center than at the sides. In the other the slope or camber is given to the earthen sur- face, and the metal put on of one uniform thickness. Of METAL /J G-KCATCK AT -rue. CCMTER TM/>M #r rue >tt 9' -Sec r/ on OF McrsiLLeD ROAD WHEKC. rue METAL u OF The Metal to be of Uniform Thickness. The advocates of the first mentioned system say there is more wear at the center than at the sides, and consequently the metaling should be thicker at the former. Those in favor of the uniform thickness say that as an equal pressure should be sustained by the earthen base under all the wheels, so the resistance (indicated by the thickness of metal) should also be equal, and, that the extra wear at the center on a country road is inappreciable ; the weight thrown by the inclined plane of the road on the lower side wheels compensating, in great measure, for the slight extra traffic at the center. My experience is in favor of a uniform thickness of metal ; especially as it prolongs the time to a general renewal of the metaled surface, which has to be done sooner in the ununiform system, as the sides are soon worn too thin for traffic, and it is difficult to bring them to the proper thickness without a general renewal of the whole cross sec- tional surface. The cross slope, or camber of the road, should therefore be given to the earthen base, and the metal spread on it of a uniform thickness. Preparing the Earthen Surface to Receive the Metal. While the broken stone metaling for the road is being prepared, the earthen surface or base should also be prepared to receive it. If possible, the earthwork of the road, where in high embankment, should be exposed for a few months to the action of the rain-fall, which will tend to settle and consolidate it. Immediately before receiving the metaling, all hollows and depressions, etc., of the earthen road-bed, due to settlement or the action of the rain, should be filled up, and the earthen surface given the requisite camber or cross slope from the center to the sides, as shown in the diagram. The whole sur- 382 ROAD CONSTRUCTION AND MAINTENANCE. face should then be rolled with a 15 -ton steam road roller (all unevenness and derangement of shape due to the action of the roller being promptly made good), until the roller ceases to have any impression on it. If the surface be of sand, or of such nature as to move or heap up before the roller, a thin layer of broken stone or gravel should be strewn on it. Stone Bench Marks. The earthen surface being now thor- oughly rolled, and formed to the proper curved camber, stone bench marks 8*x8"x4 ff should be sunk at 5o-feet intervals along the edges and center of the proposed line of metaling, and set in position by a leveling instrument to indicate both the height of the earthen sur- face and the base of the metaling, and for giving the proper camber to the road. Gauging Height of Metaling. Temporary wooden gauges 7 inches high to be placed over these bench marks, to show the height to which the metaling must be raised as it is placed on the road. The bench marks being placed exactly 50 feet apart can easily be found; and they will thereafter serve to indicate the depth of wear of the metaled surface. The cost of these bench marks will be small, as their sides need not be cut to any regular shape; a flat upper surface to receive the bottom of the leveling rod being all that is needed. The Earthen Sides to be Dressed off to the Level of the Spread Metal. As soon as the metal is spread to the proper height, and before the consolidation of it is commenced, the earthen sides of the road are to be brought up to the proper level all along the edges of the metaling and given the prescribed slope to shed off the rain. Rolling. The metal being now evenly spread (with the proper sectional camber) over a convenient length of road, and the earthen sides raised along its edges, the whole surface is to be rolled with a i5-ton steam road-roller, and the rolling continued until the roller produces an even, uniform, hard surface over the whole road. Any depressions or unevenness occurring in the surface during the pro- cess of rolling to be promptly remedied by picking up with a pick the defective places and adding the requisite quantity of fresh stone to bring up the surface to the proper level. The Metal Surface to be Watered while being Rolled. After the road has been partially consolidated a water cart should precede the steam roller, as wetting the metaling causes the pieces to glide more readily together and to be more firmly bound together without crushing. The cost of the water cart will be more than compen- sated by the greater expedition with which the consolidation can be completed. This is my experience of the use of water. When a ROAD CONSTRUCTION AND MAINTENANCE. 383 hard surface has been effected by the roller, broken stone screenings passed through a J^-inch mesh screen, to be spread over the metaled surface to a depth of one inch, and the road again rolled, until its surface becomes such that water will run off it. The earthen sides being now finally dressed and rolled, the whole road is now com- pleted. Gravel. Where broken stone is not procurable at a reasonable cost, or the exigencies of the local traffic does not oblige the use of so costly a material, while gravel is readily obtained, this material can be advantageously employed in making a good road. The diffi- culty in dealing with gravel is that it will not readily bind together under a roller, owing to the roundness of its particles, due to the attrition or manner in which nature has formed it. Crushed Gravel. If the gravel were crushed in a stone crusher, made to suit the smallness of its size, the difficulty due to its round- ness would disappear; as the crushing machine would, by its action* produce enough of angularity or sharpness of sides in the particles to enable them to readily bind and not be easily displaced by the hoofs of horses. Thus crushed in a machine its consolidation would be effected in the same manner as described under the heading broken stone; with, however, this exception, that the consolidation of gravel must be effected in two layers of 3^ inches each, the first layer being in great part, though not thoroughly, consolidated before the second layer is added; the latter being then rolled until a hard compact surface results. A water cart should also precede the roller, as in the case of broken stone, after the surface has been par- tially rolled. For gravel a lo-ton steam road-roller will suffice, owing to the smallness of the particles. Gravel thus treated in a crusher would prove a fair substitute for broken stone where the traffic was not very heavy, and where it is readily procurable. It is far cheaper than stone, requiring in many cases to be but shoveled into a wagon, and it will cost less to crush and roll If, however, the gravel is to be used in its natural state, as got from pits and the beds of rivers, a certain portion of dry, pulverized clay, in the proportion of one of clay to eight of gravel, must be mixed with it before it is spread on the prepared earthen surface or road-bed, on which it should be placed, as already directed, in two layers of three and a-half (3^) inches each, and consolidated in the manner described in the preceding paragraph. A layer of about one-third of an inch (not more) of sand should be strewn over the consolidated surface, and the roller finally passed over it until the sand is absorbed in the gravel surface. Coarse Sand. I have also used coarse sand as a road material, the largest particles of which were about the size of peas. This 384 ROAD CONSTRUCTION AND MAINTENANCE. will not make a first-class road in very wet weather, but will make a good dry-weather road, and will render an otherwise impassable road, in wet weather, such that a team will pull a load through somehow, as the expression goes. It is a cheap method of paving a fairly good road for nine-tenths of the year. It may be the fore- runner of a good macadamized road, when the exigencies of traffic demand the latter. The sand should be screened so that a portion of the finer grains are eliminated from the mass. The road-bed should be prepared as previously described, and not more that two inches of sand spread at one time, and then rolled. The roller, a lo-ton steam roller, being preceded by a water cart. The road should then be open to traffic fora month or more, and then another layer of from one to two inches added, this again rolled, and so on, until some six or eight inches of coarse sand has been absorbed, when a fairly passable road in ordinary wet weather will result. Frequent rolling during the year will keep it a good road in fine weather and a passable one in wet. Where, for miles, a road runs along a river or sandy creek, the procedure above described will prove a cheap method of paving a fairly passable road even in ordinary wet weather. Trees. Suitable shade trees should be planted along the lower berms reserved for such purpose. They should be planted six feet from the toe of the earthen embankment of the road, and 30 feet apart. Mile Posts. A first-class road may be said to be incomplete without mile posts. The initial point of measurement for these should be some prominent building in the city from which the country roads radiate. The mileage numbers should be of a size so that he who rides may read. THE REPAIR AND MAINTENANCE OF ROADS. A road however well constructed will wear under traffic ; and, therefore, repairs, and in time more or less renewal, of its maca- damized or metaled surface is necessary. The Effect of Traffic on a Metaled oad.T\\z first effect of traffic on a country road is the formation of ruts by the continuous passing of wheels over the same parts of the road. If these be not repaired or refilled they at length become so deep, and the crust of metal below proportionately so thin as to be unable to sustain the weight of a heavily laden wagon. The wheels then break through to the earthen base. The holes thus formed fill with water which softens the earth below, and every wagon wheel moving along the same line goes with a thud into these holes, increasing them in length, breadth and depth ; and the road thereafter becomes an ROAD CONSTRUCTION AND MAINTENANCE. 385 impediment rather than an aid to traffic. In a city there is not the same tendency to form ruts as on a country road, as in the former the frequent changes of direction to avoid other vehicles produces a more uniform wear over the whole surface of the road. How to Make Repairs. As soon, therefore, as a rut or hole, or depression becomes one and a half (i) inches deep on a broken stone road, or one inch deep on a graveled road, the rut or depres- sion should be repaired or refilled in the following manner : The part affected should be cut out square (to use a well understood expression), as shown by the dotted lines, to the depth worn out, and the space thus excavated refilled with the same description of fresh material to a height a little above the level of the sides of the exca- vation, so that it will sink down to that level when consolidated. If the rut or hole thus repaired be of small extent the section hand in charge of the repairs of that portion of the road should go over it with a stone or iron rammer, about 7 inches diameter, and weighing about fourteen (14) pounds, and ram it to a hard surface, using the material dug out of the hole, instead of screenings, for the top coat. If the rut repaired be of any appreciable length it should be gone over by a small road iron roller drawn by a single or double team according to the width of the rut, and the size or weight of the roller necessary to consolidate it. For the purpose of these repairs there should be a two-ton and four-ton roller on the road establish- ment, to draw which teams should either be kept or hired when necessary. The section man in charge of repairs should always have the means at hand of repairing the road. Repair Material. To enable him to conveniently do so a cer- tain quantity of broken stone should be stacked at every 100 feet along the lower earthen berm reserved for trees. The quantity thus stacked at intervals of 100 feet should not be less than a cubic yard of road metal, or 52 cubic yards to the mile. Repair Implements. The section hand should also be provided with a wheelbarrow, a pick, shovel, spade, four-pound hammer, and a road rammer, as implements for the execution of his work. When the repair material thus conveniently placed at his disposal has been reduced by use to about one-third of a cubic yard the stack should be renewed to the full cubic yard. Repairs of Gravel Roads. By the means just mentioned the section man will always have at hand the means of repairing the 386 ROAD CONSTRUCTION AND MAINTENANCE. road the moment he considers such necessary. When a graveled road shows signs of roughness or disintegration of surface, the best remedy is to fill up all unevenness with the stated mixture of clay and gravel, and to pass a steam roller over it, preceded by a water cart or after a shower of rain. Repair of Earthen Sides. The earthen sides to be kept in repair by excavating the earth required from the side trenches. By this means the double object will be effected of keeping the trenches clean and free from drainage, and the earthen sides of the road in proper order. Itemoval of Dust. In France it has been found by experiment that a road wears better by removing the dust off it; this dust act- ing as emery powder does in the hands of a jeweler. Where labor is cheap, the removal of dust might be effected by human labor, but I doubt whether it would be advantageous to do so in America. I have never seen a sweeping machine, such as is used on stone and asphalt pavement, tried on a macadamized or broken stone road; but if it took off the dust without disintegrating the road surface, it might be advantageously used on that portion of a road within four or five miles of a city. Renewal of Metaling. When the general surface of any length of road is so worn as to be reduced to about 4^ inches in thickness, a renewal of its surface is necessary by the addition of a coat of as much new metal as will bring it to the original thickness. The reduction of thickness from wear can be determined by exposing the stone bench marks placed, as has been directed, every 50 feet along the center and edges of the metaling. The old surface should be roughened up by means of a pick, and the new metal added and consolidated in the manner already described for the original metal- ing of a road. County Engineer and Assistant Engineer. For each county there should be an engineer and assistant, whose duties should not be solely confined to the earthwork and metaled surface of the road, but who should also have the designing and construction of all cul- verts and bridges required for the cross drainage that impinges along the road alignment. Both these officials to be appointed by the County Commissioners from qualified engineers, of not less than eight years' professional standing in the case of the engineer, and five years Qf his assistant. The salary of the former should not be under $1,800 a year, and of the latter not under $1,200, with ten cents per mile added in each case for every mile traveled on duty ; with the exception that no mileage allowance be granted for dis- tances under five miles from headquarters or place of residence, per- manent or temporary. ROAD CONSTRUCTION AND MAINTENANCE. 387 State Engineer. There should also be a State or chief engineer, whose jurisdiction should extend over all the county engineers, who should submit to him all their plans for both road and bridge con- struction. The chief engineer should be competent to advise the county engineers on all matters pertaining to their duties. There would thus be a guarantee for efficiency and uniformity in all works undertaken throughout the State. Minor Establishment. For road repairs there should be a sec- tion hand in charge of the repairs of two to four miles of road according to the amount of traffic ; and a foreman, with extra salary for a horse, for every 30 miles of road. When special repairs were needed, the petty establishment should of course be increased. There should be at least one steam road roller for every county, and a 2-ton and 4-ton horse iron roller for every 20 miles of road. The present system of repairing and maintaining country roads, by exacting so many days' labor in the year from the farmers, should cease. It is obvious from what has been stated that roads cannot be maintained in good order under such a system. Cost of Road Earthwork. The cost of constructing roads in the manner directed in this treatise will vary, in the case of the earthen road-bed, according to the undulating or hilly nature of the country passed through. In the prairie lands of Illinois, Minnesota, Iowa, Texas, etc., the cost of the earthen road-bed will be from $500 to $800 per mile ; in more undulating land, from $700 to $1,500, and in hilly country from $1,500 to $2,500 per mile. Special miles will in each cost above these figures. Cost of Broken Stone Metal. The cost of the macadamized or metaled surface will vary according to the material and the distance it is transported. It will he from 50 to 75 cents per consolidated square yard, for a 6-inch consolidated thickness, if of broken stone; or from $5,000 to $7,500 per mile. Cost of a Graveled Road. If the material be gravel, the cost will vary from 30 to 50 cents per consolidated square yard of 6-inch thickness, or $3,000 to $5,000 per mile. APPENDIX. The preceding notes and remarks on the construction of mac- adamized roads is the result of many years' experience in their construction in British India, in the Public Works Department of the Government of India. The country roads there are all macadam- ized or metaled, to use a more familiar term in use there. They are also thoroughly maintained in good order; and, taking the vastness of the country into consideration, and the efficient state in which 388 ROAD CONSTRUCTION AND MAINTENANCE. the roads are kept, they may be said to form the most magnificent system of internal communication of that nature in the world. The Government of British India holds and acts up to the principle that it is as necessary to keep the country roads in good order as it is to maintain railroads. They each have their value, and in their way should be equally efficient. The first journey taken by all commod- ities is from the farm or field along a wagon road ; and it is a just and right principle that the men (farmers) who convey these com- modities to market and to the railroad depot should have every facility and convenience of doing so, which can be provided by good roads. The time and labor lost by the farmers in hauling their goods along bad roads adds to the price of their commodities that is, to the food of the whole population, and to all the raw products of commerce ; for the farmers must compensate themselves in some measure for the diminished power of their draught animals, and the extra wear and tear of their harness and vehicles, caused by bad roads. In some transactions the loss suffered by one man is the gain of another, but in the case of bad roads there is a general yearly loss to the whole community of many millions of dollars. The Legislature of each State should therefore take up the matter, and establish such laws and regulations, and make monetary pro- vision for the construction of so necessary a benefit to the general community as good roads. For further reference regarding roads, see Harper's Weekly of August 10, 1889. An article by Jeremiah W. Jenkins, published by the American Economic Association. An article in Scribners Magazine, by N. S. Shaler. Governor Hill's message to the New York Legislature on the necessity for constructing good roads. The Engineering and Building Record, of New York and Lon- don, for the latter half of the year 1889 and beginning of 1890. ROAD CONSTRUCTION AND MAINTENANCE. 389 CONSTRUCTION OF ROADS.* BY JOHN P. PRITCHARD ( " A SIMPLE SCRATCH " ), QUINCY, MASS. The first thing to do is to have the road properly laid out by a competent engineer, making lines and grades which include all earthworks, cutting and filling, culverts, drains, bridges, etc. The earth road-bed to be free from loam ; excavate to the re- quired depth, then grade to the proper shape ; to be well watered with a one-horse watering cart, and then rolled with the steam-roller; fill all depressions which shall appear with the same material as the road-bed, roll until it is compact and solid, then spread two inches of sand over all for a bed for the paving. On this road-bed set the paving stone, set a line of paving through the center of the road 9 inches in depth, then gradually diminishing to 5 inches to line of curb, the stone always to be laid with the best bed down, laid close and in parallel lines, as near together as possible, across the road, breaking joints. The stone for each section wants to be as near of a size as possible ; no stone should exceed 15 inches, except through the middle of the road, then a single line can be laid parallel with the road ; after having paved 100 feet the stone must be wedged up tight with spalls, chips, etc. It is not necessary that the wedges should be driven to the bottom of the paving ; after wedging, all the projections sticking up above the grade line of the paving should be broken off ; no wedging to be done within 15 feet of the face of the paving ; almost any kind of stone will do for the paved bottom if they are carefully and well set ; after the bottom is thus prepared the steam-roller can be run over it, commencing at the curb ; work towards the center ; the amount of rolling for this bottom will have to depend on the superintendent of the work ; never roll within 20 feet of the face of the paving ; never use screenings from gravel to wedge or surface up the paved bottom. On top of this foundation lay 4 inches of broken stone (when rolled), not to exceed 3 inches in size ; the tailings and spalls from the breaker can be carted on to the road and men with hammers can break them to the required size, or, they can be thrown on top of the paving and used for wedging. Ballast and stone chips from stone sheds can be used for this course if care is taken to have them broken up to the proper size ; in spreading this course never spread within 18 inches of the curb line ; the roller will take care of this space by crowding it down to the curb line. There should not be any stone less than 2^ inches in this course ; great care should be taken to pick out all the round stone that may appear, * The Engineering and Building Record Competition. Third Prize Essay. 390 ROAD CONSTRUCTION AND MAINTENANCE. if not they will work up through the surface. This course is now ready for the roller, and a great deal depends on properly rolling this course. The flat stones must be broken or picked out as fast as they appear; the water cart can now be put onto the road; it will do more good than to put on binding, which should be avoided if pos- sible, and should never be resorted to unless the stone round up and will not bind ; such places will occur when very hard and angular stone are used, but a few shovels full of binding and a little water will make them bind all right. On top of this course lay 3 inches of broken stone that shall have passed through a 2-inch circular hole, and spread with a shovel ; never use a "rake ; be careful and pick out all flat and round stones. Use the water cart freely on this course if dry weather. On top of this course lay enough broken stone that shall have passed through a i^-inch circular hole, and spread with a shovel thick enough to fill all interstices ; to make it almost smooth this course wants more rolling than either of the others. On top of this course comes the binding. Use the screenings from the breaker that have passed through a i-inch circular hole, 2 inches thick. This course contains stone and dust, and when it is well watered and rolled, the dust and loam washed out of it, you will have a good surface, and it will be ready for public travel. Sand can be used for binding instead of screenings, but in my experience screenings are more satisfactory for our roads. The stone used in the second, third and fourth layers should be of one texture, near as possible ; the wear will be more even. A great saving can be made in this class of road by paving a space through the middle wide enough for teams to pass both ways. The sides can be macadam or gravel. GRAVEL ROADS. In building gravel roads commence and screen through a 2^- inch screen ; then screen this through a i^-inch screen ; then this through a %-inch screen; when the bed is properly shaped, wet and rolled, put on the 2^-inch, wet and roll; then put on the i^-inch, wet and roll ; then put on the %-inch, wet and roll. The required thickness of each course will depend on the kind of road you are building. For main or side roads the custom in most towns is to take the gravel from the bank, dump it on the road, throw the loose stones into the bottom, and cover them up with the small ones ; in a few years the small ones are on the bottom and the large ones are kicking about the top of the road. ROAD CONSTRUCTION AND MAINTENANCE. 391 MACADAM ROADS. Have the bed properly shaped, wet and rolled ; coarse stone ballast tailings from the breaker will do for the foundation course, but they must be well broken so they will all be of even size. Next a course of 2^-inch from the breaker, four inches thick ; next course 2-inch from the breaker, three inches thick ; next course surface up with i^-inch, well rolled ; cover with screenings from the breaker that have passed through the i-inch circular hole. Great care should be taken to have the flat and round stones, as well as all rotten stone excluded ; all courses to be well watered and rolled. Have the two last courses of one texture, as near as possible. MAINTENANCE OF ROADS. After a road has been properly constructed it should always be maintained, no matter what the amount of travel there is on it. Ruts and hollows must be filled up as soon as they appear. No water should be allowed to stand on top of the road ; keep the road as free from dust and mud as possible. When filling ruts and holes good hard metal that has passed through a circular hole, one and a half or two inches, should be used, loosening the bottom with a pick to facilitate the binding. To repair a macadam road put the spikes into the roller ; go over it three or four times, pick out all the large stones or break them up, then run the roller over just enough to smooth it up a little, then put on the stone, never over 2}4-inches in size, and for side streets 2 inches will do ; then surface with i^-inch size, wet and roll. You will not have to put any binding on this, for enough binding will work up through it if it is properly wet and rolled. The great trouble in regard to the maintenance of roads in Massachusetts is that in the fall, winter and spring, when the roads need looking after the most of any time in the year, the appropria- tions are all spent, the men discharged, and nothing can be done until after the annual elections ; then they have no time to look after repairs, but get to work on new work, and before they get half done on the work laid out to do the money is all gone. We shall never have good roads in Massachusetts until the business of road- building is taken out of politics and taken in charge of by the State. Good roads can be constructed by towns, if they are not rich enough to buy a steam roller, but no town can afford to be without a stone-breaker ; and because a town does not own a steam roller or stone-breaker it is no excuse that they cannot build good roads. With forty or fifty stone-breaking hammers, an iron sectional roller weighing two tons, and a competent man as superintendent, good 392 ROAD CONSTRUCTION AND MAINTENANCE. roads can be built. I built a mile and a half of Telford road before I even knew how to use a steam roller or a stone-breaker. They will cost more though and take more time to build. A good road plant consists of a 10 or 15 ton steam road roller, a 9x15 stone breaker, and a revolving screen with i-inch, i YZ -inch, and 2-inch circular holes. A great saving can be made in breaking stone by having the breaker set up 15 or 20 feet above grade, or an elevator can be used to convey the stone, and have the top of the mouth to the breaker even with the floor. This saves a great deal of handling the stone. One man can do as much as two where they have to be lifted from the platform. Another advantage of setting up the breaker is that hoppers can be constructed and the stone drop direct into the mouth of the screen from the breaker, then three different sizes into the hoppers. Each hopper contains 40 tons. These hoppers can rest on a heavy frame of hard pine timber, high enough from the ground so that a cart can be backed under any of them, and by the simple motion of drawing a lever allows the contents of the hoppers to fall directly into the carts, and a reverse motion of the lever closes the slide tight. A cart can be rilled in one minute. Three men can break 100 tons a day. Cities and towns will find it to their advan- tage to look into this mode of arranging their stone breakers. There is a stone breaker at work in a city near Boston that takes nine men and two horses to keep it a going. The reason of this is because it is set on the ground, and the stones have to be handled over twice before they are put on to the road. They are shoveled into the carts by hand but don't it make work for the poor laboring man ? and don't we want his vote ? That is the whole secret of bad roads in Massachusetts. Potter says bad roads have a tendency to make the country disagreeable as a dwelling place, and a town which is noted for its bad roads is shunned by people in search of rural homes. There is no kind of work done in the New England States that there is so much money wasted on as there is in building and taking care of roads. Shaler says, in no phase of public duties does the American citizen appear to such disadvantage as in road building. Learned says towns complain of the first cost of macadam roads, while annually spending millions of dollars and moving count- less tons of earth without having a good road. Whether I get the prize or not for this essay, if it can be called so, if my instructions are followed in regard to Telford road building by any competent superintendent, I shall have no fears as to the result, for I have been building just these kinds of roads since 1877, and some of them are having the heaviest traffic passing over them of any place in this country ; talk about your thin roads, we would cut them up in one ROAD CONSTRUCTION AND MAINTENANCE. 393 week with the rain-fall we have had this winter. I can't say any- thing about asphalt ; I wish I could ; I have never had anything to do with it, but I have great faith in it, and it will be the coming paving ; it is only a question of time. The roads that I have built are open for inspection. I have not given the cost of any of the roads that I have built, because the prices must vary according to the length of haul and price of stone. I built a mile of Telford road, 40 foot roadway, for $7,000. I have built a half a mile that cost $8,000. The first one, some of the material was hauled over half a mile ; the other, some of the material was hauled three miles. Seventy-five cents per square yard is the price quoted by the different road builders as a fair price for Telford roads. Good sidewalks this season of the year is what we want. The best material for muddy walks is coal ashes ; mix a little loam and loose fine salt ; have it mixed up in large piles, when you have soft weather and the frost is coming out of the ground, you will find it a good deal better than gravel ; it will bind and become compact with a good smooth surface and will shed the water. Every town should have a large shed where they could have the good clean ashes that is collected and deposited ready for emergencies. NOTE. IN preparing the following abstracts of the essays given Hon- orable Mention, the purpose of the Committee of Award was to confine them to such propositions as were not substantially covered in the three essays published and thus avoid unnecessary repe- tition. The omission of parts will, therefore, be understood as no reflection on the essays. BY PROF. JOHN V. HAZEN ("GRANITE STATE"), HANOVER, N. H.. (Abstract.} Services of an Engineer Should be Secured. The skill of a com- petent engineer is of great value in laying out roads. Figure i shows an old and a new road laid out in writer's native town. The new road is only 234 feet longer, and an elevation of 60 feet is saved and maximum grades are reduced from i in 4 to i in 10, and might have been reduced more. 394 ROAD CONSTRUCTION AND MAINTENANCE. Curving Roads not so Much Longer as They Seem. Curving roads on a flat country are not so much longer as they seem. A road between two places, five miles apart, curving so that the eye can nowhere see further than a quarter of a mile, will only be 225 jfta.be.' feet longer than a straight one joining the same termini. Within proper limits a road may wisely be increased in length by 15 times the vertical height avoided by the detour. A Narrow Road Frequently the Best. A well kept narrow road, when width is sufficient for traffic, is much better than a broad one with no greater amount expended for repairs. ROAD CONSTRUCTION AND MAINTENANCE. 395 Earthwork Paid f>>r in Excavation. Earthwork and rockwork should be paid for in excavation on account of shrinkage in the former and increase in volume of the latter when placed in embank- ment. The Best Embankment Built in Layers. Embankments are usually made by dumping the earth from their ends, keeping them up to their ultimate height, but wider at the top and narrower at base than when finished. The better system is to make them in layers of a foot thick, each successive layer being compacted by depositing those which follow. Method of Underdrawing. For underdrainage in heavy soil ditches are dug transversely of the streets at intervals of 20 to 30 feet, and with a fall of from i in 100 to i in 20. The drain may be of stone or brick, built like a small culvert, or of agricultural tile. The latter are the most effective and generally cost no more. Two- inch tiles cost from $11 to $20 per 1,000 feet. They should be laid with above fall, with the closest possible joint, end to end, in a nar- row trench of uniform slope carefully aligned. Such a drain placed 2 feet deep will cost, with tiles at $15 per 1,000, about 45 cents per rod when completed. The English Method of Laying. J. Bailey Denton, an English authority, advocates two lines of 2-inch tiles beneath the two edges of the traveled road longitudinally. Others place a line of tiles directly beneath the side ditches relieving them of much surplus water. This has the disadvantage of not much removing the moisture from center of the roadway. In another system one line of 3-inch tile is placed directly beneath the center of traveled road. This has the advantage of being cheaper than the others; of conveying away the moisture from center of the roadway, and, on the whole, is the most satisfactory. Cross drains connect at intervals the second and fourth systems with the side ditches, the latter being sufficiently deep to receive the outflow. Well built gutters, 18 to 24 inches deep below bed of road, with finished surface of side ditch above, kept clean, free from grass, weeds and stones, will frequently render underdrainage unnecessary even in quite moist soils. Culverts. Culverts for transferring the water from the higher to the lower gutters should be put in at every depression. These may be of vitrified stone 20 to 24 inches in diameter, oval or egg- shaped cement pipe of stone, brick, or of wood if constantly under water. Culverts should have a fall of at least i in 100. Care should be taken to make them large enough to carry away the water with- out overflow. A rule sometimes used is A = C/y/ M where A = area of opening; M = drainage area in acres, and C A coefficient de- pending on country; as i for a flat country, i-j 6 ^ for hilly, and 4 for mountainous. 39 6 ROAD CONSTRUCTION AND MAINTENANCE. Earth Roads. While earth roads are not ideal roads, they are frequently the best a town's finances will allow. Their ordinary con- dition may be much improved by careful attention to grades, sur- face drainage, underdraining, and keeping the surface as nearly homogeneous and hard as possible. An occasional rolling will have a marked effect. Amount of Rolling. The total amount of rolling necessary will vary with materials and soil. From 30 to 60 hours per 1,000 yards is desirable. Silicious sand, clay or clean sharp gravel are some- times used as a binding material. The amount of crowning in use varies from -f% to -fa of the chord, or a slope of i in 24 to i in 40. Some engineers increase the slope with the grade. In Providence grades of 0.5 to 4 feet per 100 have a transverse slope of .04 per foot. 4 to 6 " " 4< " .05 " 6 to 9 " " " " .08 " This provides for a rapid conveyance of surface water to side ditches. The total thickness of macadam varies with the locality. Six to ten inches is the usual thickness. The latter being used in or near cities. Good roads have been made only 4 inches thick, and as it is often a question of thin roads or no improved roads, they are worthy of trial. A lo-inch road costs from $i to $1.75 per square yard, while good 4-inch roads have been built for 28 to 38 cents. Where the traffic increases, or sub-soil is soft, the thickness should be increased. Some engineers vary the thickness with the grades, decreasing it as the grades increase; 4 to 6-inch roads recently built near Plainfield, N. J., are said to have cost from $3,000 to $8,000 per mile; some 4-inch roads in Bridgeport, Conn., about $3,000 per mile. Quality of Stones of Sub-pavement. In Telford paving the spaces between the blocks should not be filled with anything smaller than stone chips, otherwise an essential characteristic, capacity to drain off rapidly whatever surface water works through, would be destroyed. Total Thickness of Pavement. The total thickness of Telford pavement will vary much with the locality and expected traffic. It should never be less than 6 and seldom more than 16 inches, and it may decrease as the grade increases. In cost they vary from 90 cents to $1.75 per square yard. Some roads recently built in New Jersey cost from $8,000 to $10,000 per mile. Advantages of Telford Roads. The advantages claimed for Telford roads are that the sub-pavement needs no renewal, and provides for thorough drainage. That in clayey, compressible soils the clay does not work up into the voids; that the broken stone does ROAD CONSTRUCTION AND MAINTENANCE. 397 not work down into the soil ; that extreme winter weather has no effect upon it nor does the ensuing thawing out. The advocates of macadam roads claim that the earth does work up into the voids of a Telford pavement; that the broken stone works down into the same voids, and that the broken stone wears out much more rapidly on a Telford sub-pavement than on compressed earth. Good Foundation Important. Foundations may be made of sand or blast furnace slag compacted by rolling. Repair of Earth Roads. Earth roads should be kept smooth, hard, up to grade and cross-section by the addition of suitable materials at frequent intervals, and in small quantities at a time, on all places out of grade, securing a surface such as shall quickly convey the water to side ditches. The latter should be kept open, of uniform and sufficient slope, free from rocks, ridges, depressions, and continuous to some natural or artificial outlet. Sprinkling and rolling are valuable adjuncts of repair, especially in dry weather, and a thorough rolling in spring, after ground has settled, is of marked benefit. Sprinkling and Rolling Advantages. In dry weather, sprinkling and running the road-roller backwards and forwards over a macadam road will preserve its surface, or if water is not at hand a coating of sand or other binding material does the same. Repair of Large Areas. When large areas are repaired, the work, if possible, should be done in damp weather. Thickness Worn Out per Annum. French experience shows that, measured by thickness, the annual wear on ordinary country roads is seldom over inch, and on the most frequented roads i inch. Systematically maintained English roads confirm these results. Cost of Breaking Stone and Repairing Roads. It costs 70 to 80 cents per cubic yard to break trap rock with crushers ; the cost of delivery varies with the distance, about $1.10 for two miles, or a total of $1.90. For -inch wear, road 20 feet wide, it will take about 164 yards, costing $300 per mile for material. Plainfield, N. J., roads are said to have cost last year, with careful watching and immediate repair of weak spots, $1,000 for 40 miles. Time will show annual cost for complete maintenance. Cost of Transportation on Poor Roads. On a macadam road, recently built in Connecticut, it is said that 5,000 pounds can be hauled where 1,200 to 2,000 was a good load before rebuilding for the same team. A farmer living ten miles from market, and having 100 tons annually to sell, on the unimproved road would have to make at least 100 trips, on improved road 40, a saving of 60 days' time, which, at $2.50 per day, would be $150 ; probably several times his tax for the improvement. 398 ROAD CONSTRUCTION AND MAINTENANCE. Follow Good Roads. The introduction of macadam roads in parts of New Jersey is said to have doubled, in some cases, the value of real estate. Hoboken to Patei Bridgeport, Conn Plainfield, N. J.., Fairfield, Conn . . Franklin Townshi Westfield, N. J.. Fanwood, N. J. . , Union Township, Linden Township City of Rahway, 1 | O a HH Locality. tj ? : * ^ e_( L, Z : 'r 1 : | i I 4* * ^ M M to 10 M to to CO o &! |f| ^ ^-A^~. ^^_^ o ^ OT ^ OJ . : : : : Iff 11 M M 00 fD : : : | ?" 2.P*5 K : : : | % "^a I . a w> M| O^tO KKg 0) >->\ en 4^ en <>j u> M M M en 8 a " i LO .(- ! 1 "g 1 00 .2 : : = - S ' ^ "F M : : 1 ? r* SNO 1 ^ o ^ -J S' - pi l-t> ~ : P! fB * fl> p f* : pi ? Kansas City has just renewed five miles at prices varying from 1.17 to $1.85 per yard. ROAD CONSTRUCTION AND MAINTENANCE. 399 SAMUEL L. COOPER (" PALISADES*'), NEW YORK CITY. {Abstract.} Grades on First Class Roads. It costs more to maintain a grade of i in 20, than a grade of i in 40. Width of Roads. The metal should be 16 feet wide for ordi- nary country roads, and as much wider up to 25 feet as the money available will permit ; but for village roads and suburban pleasure drives, the metal should extend across the road to the gutter pave- ment on each side. Expense of making the metal 16 feet wide will sometimes compel a narrower width, but it should not be made less than 13 feet, as that is the minimum width on which wagons can pass each other with safety. The following are suggestions for dimensions of roads of different classes : Total Width. Width Roadway. Metaled Width. For a First-Class Road 75 to 100 40 to 60 25 to 35 For a Second-Class Road 50 to 66 25 to 35 16 to 25 For a Third-Class Road 40 .25 13 Cr(nun. When the surface of a road is poor the crown should be greater. Consolidation vs. Mass. Perfection in roads cannot be obtained without proper consolidation of the materials that make the road. This is more important than mere mass without consolidation. Steam Roller. It can best be obtained by a steam roller of about ten tons weight, and any community that seeks the best roads for the least outlay can get the most for its money by using the best materials, buying a steam roller, and employing an intelligent road builder to make the roads and maintain them. For Macadam. Each layer of stone must have a certain amount of binder to make it a compact mass. The best material for the purpose is screening from the crusher, but when that is not available, clean gravel and sharp sand should be used. The rolling should be continued on the finish until water will flush over the entire surface. Sides of Road to be Rolled. The sides of the road between the gutters and the metal should be carefully graded and rolled to ultimate resistance and a true surface with a 5 -ton roller. The cost of macadam roads in the vicinity of New York, by contract, to prepare the surface, provide good trap rock, spread and roll the same ready for use, is about : 50 cents per square yard for 6 inches of metal. 65 " " " " 8 80 " " " " 10 400 ROAD CONSTRUCTION AND MAINTENANCE. Foundation for Telford Road. The foundation and broken stone will seldom be required to be thicker than 12 inches, and unless the width to be metaled is more than 16 feet, it should be of uniform thickness across the section. When the width is over 16 feet, the thickness at the sides may be reduced to 10 inches. Foundation Stone, Size. The foundation stones for a 1 2-inch pavement should be 7 inches deep, not over 4 inches wide on top, and from 8 to 12 inches long, and fairly uniform and regular. They should be of the hardest and toughest stone available, preferably trap rock, and laid with the joints widest on top, in parallel courses, breaking joints by at least i inch across the road. After being set, they should be wedged firmly by inserting and driving down with a bar, spalls of the same stone, in every possible place, until the whole foundation is solid and firm. All irregularities and projections above the 7-inch line should then be broken off carefully with a hammer, so done as not to loosen the foundations. All the rest of the joints not then filled with spalls, should be filled with spalls and chips pounded in with a hammer, so that the top is a regular but not too smooth surface. An 8-inch pavement should have a 5-inch foundation. The bottom course of stone should be broken to pass a 2-inch ring, and the top a i-inch ring. The binding and rolling should be the same as above described. In the vicinity of New York the cost of a Telford macadam road 12 inches thick is about $i. TO per square yard ; 10 inches thick is about $i per square yard ; 8 inches thick is about 90 cents per square yard. Six-inch Roads. We are prepared to say that success is entirely possible with 6-inch macadam roads, properly made and main- tained. Such roads can be built in the vicinity of New York for from $5,000 to $6,000 a mile, with a metaled roadway 16 feet wide, and when skillfully made, and thoroughly maintained, they answer all the purposes of a more expensive road; if neglected, however, they will soon go to pieces. Essentials for Success. The following are essential to success with 6-inch roads: (1) Good stone, preferably trap rock, and screenings or gravel as a binder. (2) A steam roller of about ten tons weight. (3) The services of a man who knows how to make such a road. (4) Constant and intelligent treatment in maintenance, par- ticularly during critical periods. ROAD CONSTRUCTION AND MAINTENANCE. 4OI Proper maintenance includes: (1) The removal of the wear of the road, and its prompt replace- ment by new material. (2) The immediate repair of ruts, holes and washouts. (3) The keeping clear of the gutters and culverts. (4) To these should be added additional care during critical periods, when the frost is leaving the ground, and during prolonged seasons of wetness or drought. General Repairs. In the fall of the year, the road should be put in first-class shape, to better resist the damaging effect of frost during the coming winter. More general repairs, such as an entire resurfacing, will be necessary periodically, according to the thoroughness of the con- struction and the amount of traffic. FRANK B. SANBORN (" ROY "), BROOKLINE, MASS. (Abstract.) Records. The expenses incurred by the details of carefully located side-lines will not usually equal the cost of one of the many law-suits that the town will be obliged to withstand on account of indefiniteness of street lines. Drains. In an address before Maine Board of Agriculture, C. B. Stetson said: "It is clear that neither our farmers nor our road makers half appreciate the wonderful results which can be secured by thorough drainage of fields and highways by keeping them, so far as water is concerned, in fit condition for perpetual service." For the drainage of ordinary highways the writer recommends tile drains laid at least three feet deep in trenches 20 inches wide. After the tiles have been laid and the joints well protected with tarred paper or cheese-cloth the trench should be filled with small stones not more than three inches in diameter the stones laying near the pipe should be carefully placed so as to protect it from the superimposed weight. Large stones which nearly fill the trench exert simply a downward thrust and should not be used. In ordi- nary soil a trench can be dug, the tiles laid and covered with stone, as described above, for 25 to 50 cents per linear foot. The writer has had charge of the construction of two roads the past year which were drained by 4, 6 and 8-inch tiles for 35 cents per linear foot. Henry F. French says in his book on Farm Drainage: ". . . 402 ROAD CONSTRUCTION AND MAINTENANCE. drainage with tiles will generally cost less than one-half the expense of drainage with stone drains and be far more satisfactory in the end." Road-bed. It is preferable to make the width of drive-way proper (which includes the gutters) some multiple of 8 feet, which is about the width necessary for each team. Requisites. It is better to bring good material, if necessary, from a distance rather than make use of poor material for road making. Conclusion. Finally, engineers of vast experience have con- cluded, that: A perfectly good road should have a firm and unyield- ing foundation, good drainage, a hard and compact surface, free from all ruts, hollows or depressions. The surface neither too flat to allow water to stand, nor too convex to be inconvenient to the traffic; and free from loose stones. A. T. BYRNE, C. E. (" ZAMORA "), BROOKLYN, N. Y. (Abstract.} It is advisable for road constructors to abandon precedents and build roads which will best suit the requirements of the traffic. The subject of the proper construction and maintenance of roads has never been considered by the people in more than a lim- ited and superficial way. A lack of public appreciation of their true value, a mistaken idea of economy, and, in most States, the exist- ence of laws that make and permit bad work, has made their condi- tion a conspicuous blot upon the page of our general progress as a nation. The system of requiring personal service upon our country roads by our rural population is unsound in principle, unjust in its operation, wasteful in its practice, and unsatisfactory in its results, Road Laws. New legislation is needed, but no legislation can produce good roads until the people are willing to pay for them. New Laws. First, the burden of the leading lines of commu- nication should be borne by the whole community. Second, the employment of skilled engineers to superintend the road making and repairs. Third, the abolishment of personal labor, and the levying, instead, of a money tax. The money tax will be found to be not only more equitable than the labor system, but even less bur- densome. None of it will be wasted, and those who have the skill and strength for road-work will receive back in wages more than their share of it. ROAD CONSTRUCTION AND MAINTENANCE. 403 Roads and Morality. Bad roads are the cause of more pro- fanity and ill-nature than any other trial to which human nature is subjected. Effect of Bad Roads. Nothing has led farmers' children to a dislike of the country, and a desire for city life, more than the monotony of the rural districts in the winter months, produced by the lack of social intercourse, for the want of good roads. Advantages of Good Roads. By the improvement of our roads every branch of our agricultural, commercial and manufacturing industries would be materially benefited. Every article brought to market would be diminished in price; and the number of horses would be so much reduced that by these and other retrenchments many millions of dollars would be annually saved to the public. All the produce and industry which by these improvements finds for the first time a market, is, as it were, a new creation. Cost of Roads. The road which is truly cheapest is not the one which has cost the least money, but the one which makes the most profitable returns in proportion to the amount which has been expended upon it. Maintenance of Natural Soil Roads. In the maintenance of sand roads the aim should be to have the roadway as narrow as possible, so as to have all the vehicles run in the same track ; to have an abundant growth of vegetation on each side of the rut, for by these means the sheering of the sands is in a great measure avoided. Ditching beyond a slight depth to carry away the water is not desirable, for it tends to hasten the drying of the sands, which is to be avoided. Where possible, the roads should be overhung with trees, the leaves and twigs of which, catching in the roadways, will still further serve to diminish the effect of the wheels in moving the sands about. If clay can be obtained within a moderate distance, a coating six inches thick will be found a most effective and economical improve- ment ; four inches of loose straw will, in a few days' travel, grind into the sand and become as hard as a dry clay road. Clay roads can only be made into satisfactory ways by means of effective drainage, so contrived that the least possible amount of water will remain in the material. Deep side-ditches are absolutely necessary. Cross and sub-drains may be employed to great advan- tage. The narrower the roadway the more effective will be the drainage. If sand can be obtained within a moderate distance, a coating three inches thick will form a very beneficial improvement. Trees should be removed from the borders of the road, so as to expose its surface to the drying effects of the sun and wind. Neither sods nor turf should be used to fill holes or ruts, for though 404 ROAD CONSTRUCTION AND MAINTENANCE. at first deceptively tough, they soon decay and form the softest mud; neither should the other extreme be reached, by filling up the ruts with stones. They will not wear uniformly with the rest of the road, but will produce hard ridges. Coal-slack, ashes and cinders, judiciously applied, make fair roadways; yet in many parts of the coal regions the people are pull- ing through the mud in plain sight of heaps of that material suffi- cient to cover all the roads in their neighborhood, and are heard to lament the bad condition of the roads. Stone. The qualities required in a good road stone are hard- ness, or that disposition of a solid which renders it difficult to dis- place its parts among themselves, toughness, or that quality by which it will endure light but rapid blows without breaking. Chemical Qualities. The porosity or water-absorbing capacity is of considerable importance. Of two rocks which are to be exposed to frost, the one most absorbent of water will be the least durable. For light traffic the carboniferous and transition lime-stones are sufficiently durable, make the smoothest and most pleasant roads, and possess the quality of forming a mortar-like detritus which binds the stones together, and enables it to wear better than a harder material that does not bind. For heavy traffic the lime-stones are too weak, the sand-stones too soft, the green stones too variable, the gneiss, quartz, and silicious rocks, though hard, are too brittle and deficient in tough- ness. The slates are inadmissible, the quartzose, feldspathic and micaceous granites are bad, the quartzose is too brittle, the felds- pathic too easily decomposed, and the micaceous too easil) lami- nated. The sienitic granites, which contain hornblendes in place of feldspar, are good, and better in proportion to their darkness of color, the traps and basalts are the best, though most difficult to break up. The softer rock may be used for the lower course in a pavement. Rolling. The amount of rolling, with a heavy roller, should be about ten hours for each 1,000 square yards of surface for each layer of stone, but it must be continued until all motion of the stones has ceased. After several passages of the roller, any hollows which appear must be filled up with small material and the rolling continued. Each course is to be spread and treated in the same manner. Watering is desirable where it can be done from the commence- ment of the rolling. It is done best by sprinkling. Excessive watering is to be avoided, especially in the earlier stages, as it tends to soften the foundation. ROAD CONSTRUCTION AND MAINTENANCE. 405 Binding. Binding should be spread dry and uniformly in small quantities over the surface, and rolled into the interstices with the aid of watering and sweeping. By using binding materials in large quantities the amount of rolling is lessened, but at the expense of durability. Wear and Maintenance. When the wear on a road is confined to the crushing and grinding at the surface, it is the least possible, but when a road is weak from insufficient thickness or solidity on a yielding foundation, bending and cross-breaking of the covering take place under passing loads, in addition to surface wear, and the effects are aggravated by the softening action of water finding its way into the road-bed through cracks formed in the surface, and by the disintegrating action of frost. Wear is measured by the loss of thickness in the covering. It is seldom found to exceed one inch per year on the most frequented roads. Effect of Wheels. Legislation is needed for regulating the width of wheel tires. With the same burden, a two-wheeled cart does far more damage than one of four wheels. Wheels with 2\- inch tires cause double the wear on a road than those do which have 4^-inch tires. No greater width is useful, as a wider tire does not bear evenly. The following proportions have been advised: Load on each wheel. Vehicle without Springs. With Springs. /4 to 3/ of a ton . . 6 inches. i inch X to i ton 4. " 3 i to i j^ tons 6 Wheels of large diameter do less damage than small ones, and cause less draught for the horses. AN ESSAY ON ROAD MAKING AND MAINTENANCE IN LESS THAN SIXTY WORDS. A. L. PHILLIPS ("TO THE POINT"), PENCOYD, PA. First. No unnecessary roads. Second. A competent engineer in charge of survey, location, construction and maintenance. Third. Proper macadamized roadway from eight to four inches depth as needed, if cost of stone not prohibitory. Fourth. Use of roller in construction. Fifth. Complete drainage, sub and surface. Sixth. Constant, intelligent watching and repairing by per- manent, responsible employees. 406 ROAD CONSTRUCTION AND MAINTENANCE. A PLEA FOR AESTHETIC CONSIDERATIONS IN ROAD BUILDING. BOSTON, April 7, 1890. To the Editor of THE ENGINEERING AND BUILDING RECORD: SIR: In your issue of March 29, you publish the first part of the First Prize Essay on Roadmaking in which I was greatly struck by two rules that are laid down, which, from an artistic standpoint, would be more honored in the breach than in the observance. I call attention to them because they are an epitome of the standpoint of modern engineers with regard to aesthetic considerations. The two rules are: (In making a road) "make the line as nearly straight as practicable, and when changes of line occur connect them by regu- lar curves of proper radius. When the line is intended to be straight make it so absolutely." These rules are, I am aware, considered obligatory by most engineers, for which reason an engineer may, in most cases, be depended upon pretty certainly to do a good deal toward spoiling the beauty of any landscape through which he may be called upon to make a road, with his " absolutely straight lines " and "regular curves of proper radius." It seems a pity that a few elementary ideas as to what constitutes beauty might not be instilled as part of the training of a profession that has in its hands the making or marring of so much natural beauty. But probably to most engineers the idea of considering the possible effect of the line of a road on the beauty of the landscape, and planning the road with regard to this consideration among others, seems ridiculous and quixotic. I fear that the training of most engineers tends to blunt and deaden such ideas of beauty as they may have by nature, and leads them to regard beauty as a thing unworthy of serious consid- eration. And so it comes about that fine trees of a century's growth are ruthlessly cut down and hillsides marred by deep and ugly cut- tings, when a slight bend in the road would not only preserve the trees but add to the beauty of the road; or when by following the contour of the hill, with its natural and irregular curve, the road would be given some beauty and expense could often be saved. Among the rules laid down by the prize essayist I do not find any which speaks of the necessity of considering the natural conditions which ought to be among the determining elements of a line of road, when yet the capability to seize upon and make the most of these natural conditions ought to be one point of distinction between a good and an inferior engineer. The aesthetic elements in the problem of making a road are not necessarily at variance with practical considerations. On the con- trary, it will often be found that a consideration of these aesthetic elements will lead to practical benefits and economics. To consider ROAD CONSTRUCTION AND MAINTENANCE. 407 these aesthetic questions, which are involved in a large proportion of engineering undertakings, would doubtless add to the engineer's difficulties. He would be less dependent on mere rule. It would give in each case opportunity for the exercise of judgment and skill in the harmonizing of sometimes apparently contradictory require- ments; but it would add greatly to the interest and individuality and value of his work. I appeal to the engineers themselves to consider this question for a moment, not as engineers, but as individuals who may be affected by engineering operations, to free themselves for the mo- ment from the strait-jacket of rules of their engineer's training and to consider how much beauty might be preserved, nay, might be added to our landscape, especially in suburban communities, by even the slightest consideration or forethought for beauty, for its own sake, and this often without any added expense or the sacrifice of any reasonable utilitarian requirement. It is the wanton disregard of beauty without any corresponding gain against which I protest. When our civilization reaches a point at which it is willing to sacrifice some utilitarian and material considerations for the sake of beauty it will mark a distinct advance. At present this is hardly to be expected. H. LANG FORD WARREN. COMMENTS BY THE COMMITTEE OF AWARD. The following comments are made by the Committee of Award, upon various propositions made in the several essays : Traction. Refinements as to traction are of little practical value. In every case it is desirable to fix upon a maximum grade. This being done, no exceptions should be allowed other than for very short distances. Authorities differ as to the power of horses, and as to the traction resistance of various road surfaces. Alternations in Grade. It will not do to say that these must not be allowed. The "lay of the land" and other circumstances will often compel their adoption; the only alternatives often being either a great increase in expense, or great detriment to adjacent property. In connection with the subject of grades and alignment, we com- mend the communication of H. Langford Warren, printed above. The "Angle of Repose of Vehicles" Much stress has been laid on the requirement that descending grades shall not exceed this. We believe the refinement an impossible one. What will be true for 408 ROAD CONSTRUCTION AND MAINTENANCE. one vehicle with a certain width of tire, size of wheels and axles, state of lubrication and amount of load carried will be different for another vehicle, varying essentially in these particulars. Again, what will be true for a given vehicle with the road dry and in perfect condition, may not be true when wet, frosty, etc. These latter variations will be less the harder and more perfect the road surface. Width of Road-Bed. We think the width of road metal or other covering should not be less than 16 feet, except where all traffic is very slow, where 12 feet may answer. This is a matter for the judg- ment of the engineer. Cost of Handling Earth. No fixed rules can be given as to this, as it depends so largely upon location, cost and kind of labor and teams, and thorough management. The remarks on the cost of handling earth, it should be remembered, are based on wages paid "before the war," when 75 cents a day was nearer an average than one dollar. It is a matter of regret that in this connection no men- tion was made of the cost of scraper work, and that no essayist described the working of a ''road machine," an extremely valuable implement in forming and maintaining earth roads. Weight of Roller. It is obvious that no road roller can be made heavy enough to give the same pressure per inch as the heaviest loaded wheel, but we think the use of a 10 to 15 ton roller advisable where it can be had. Binding Material. The question of the amount of binding to be used is largely dependent on the amount of rolling done, and the subsequent care of the roads. It is admitted that a considerable saving can be made by using more binding and less rolling, and where money must be made to go as far as possible this expedient is justifiable. We think, however, it cannot be questioned that heavy rolling with a moderate amount of binding, preferably screenings, gives a more durable and cleaner surface under heavy traffic. Thickness of Pavement. This is to be decided by a due consid- eration of all the circumstances in each particular case, and should be left to the judgment of the engineer. It is rarely the case that every part even of the same road needs the same treatment. Reten- tiveness of the soil, gradients, thoroughness of drainage possible, climate, character and extent of traffic, and amount of money avail- able, all have to be considered, and we deem it unwise to try to lay down hard-and-fast rules on this all-important matter. Asphaltic Pavements. The remarks of " Cesa " on asphalt pave- ments are unfortunate, as there is an entire lack of distinction between the various kinds of pavements going under this name, and ROAD CONSTRUCTION AND MAINTENANCE. 409 the essayist, by implication, condemns pavements that are satisfac- tory, on purely theoretical grounds. There is one direct error in statement, also, by this writer, that attention should be called to. He states that in England roads are under national supervision. The English highwavs are under supervision that varies in extent from the bounds of a single parish to that of a county, and while the great mass of American roads are bad enough, it is thought that no roads have been anywhere built that were better than those built by the New York Cen- tral Park Engineers in and about the Park, and we doubt if any European country can show better surfaced country roads than many in New Jersey, Massachusetts and Connecticut. Berms and Ditches. The arrangement of berms and ditches in the second prize essay is questionable, except on sandy soils. Foundation of Telford Roads. As there seems to be some dis- crepancy of statement in the several papers as to the foundation blocks in Telford pavement, we desire to state that in no case must such stone lie on the flat or broad side of the stone. The broadest edge should be down, the stone set lengthwise across the street, breaking joints in the several rows. The stones in any one row should be approximately of the same thickness. Very thick stones are bad for durability. Every needless refinement in road-making costs money, and while engineers should exact close attention to details upon which durability depends, it is not wise to expend the minute care upon them that might be bestowed upon a city street. Repairs. Where money is scarce, repairs may be made more cheaply and so as to answer a good purpose by the use of road metal, with enough clay or loam with it to make it compact quickly. One of the greatest enemies of Macadam roads is the wind, and to prevent the effects of winds the rolling and repairing of the surface as soon as is practicable in the spring, is one of the most effective means. Water, sand, clay, or loam should be promptly used if a road begins to break up in the spring winds. In making repairs, we doubt whether it is advisable (in the case of trap macadam at least) to break up the surface with spikes or with picks, where water for softening the road is available. The circumstances under which it is advisable to use material from ditches, a practice usually condemned, are not fully brought out. Washed coarse sand and gravel from side ditches may make a valuable addition to the road-bed, but the mud and fine sand washed from this will not add to the wear of the road-bed. Stone Breakers. Where suitable stone is available for road- making, a town owning a stone-breaker is more apt to have a suffi- 410 ROAD CONSTRUCTION AND MAINTENANCE. ciency of road metal than where a vote has to be passed for the expenditure of a definite sum of money at intermittent times ; but if the demagogue could be eliminated from the town meeting, it would sometimes be the case that the broken stone could be purchased more cheaply from a large establishment making the breaking of stone a business. County and Assistant Engineers. We consider the remarks on this subject in the second prize essay ill-advised. The question of time has less to do with the capabilities of a man for such work than natural ability and habits of reasoning observation. No engineer should be required to waste his employer's time by walking five miles. The better arrangement is to furnish at all times such horses and conveyance as may be required. F. COLLINGWOOD. EDWARD P. NORTH. JAMES OWEN. THE ENGINEERING & BUILDING RECORD, and THE SANITARY ENGINEER. (Established in 1877.) For the Engineer, Architect, Contractor, Mechanic and Municipal Officer. HENRY C. MEYER, EDITOR . XVIII. Plymouth, Mass. 1. XIX. Quincy, Mass. XX. Spencer, Mass. H. XXL Springfield, Mass. XXII. Taunton, Mass. nn. XXIII. Waterbury, Conn. XXIV. Wilmington, N. C. 5S. XXV. Woonsocket, R. I. XXVI. Worcester, Mass. Some Details of Water- Works Construction. By W. R. BILLINGS, Superintendent of Water-Works at Taunton, Mass. WITH ILLUSTRATIONS FROM SKETCHES BY THE AUTHOR. INTRODUCTORY NOTE. Some questions addressed to the Editor of The Engineering and Building Record and The Sanitary Engineer by persons in the employ of new water-works indicated that a short series of practical articles on the Details of Constructing a Water- Works Plant would be of value ; and, at the suggestion of the Editor, the preparation of these papers was undertaken for the columns of that journal. The task has been an easy and agreeable one, and now, in a more convenient form than is afforded by the columns of the paper, these notes of actual experience are offered to the water-works fraternity, with the belief that they may be of assistance to beginners and of some interest to all. TABLE OF CONTENTS. CHAPTER I. MAIN PIPES CHAPTER IV. PIPE-LAYING AND Materials Cast-iron Cement-Lined J OINT-M AKING- Wrought Iron - Salt-Glazed Clay Laying Cement-Lined Pipe " Mud " Thickness of Sheet Metal Methods of Bell and Spigot Yarn Lead Lining List of Tools Tool-Box Jointers Roll Calking Strength of Derrick Calking Tools Furnace Joints Quantity of Lead. Transportation Handling Pipe Cost of Carting Distributing Pipe. CHAPTER V. HYDRANTS, GATES, CHAPTER II. FIELD WORK AND SPECIALS- Engineering or None Pipe Plans Special Pipe Laying out a Line CHAPTER VI. SERVICE PIPES Width and Depth of Trench Time- Definition Materials Lead vs. Keeping Book Disposition of Dirt Wrought Iron Tapping Mains for Tunneling Sheet Piling. Services Different Joints- Compres- CHAPTER III. TRENCHING AND sion Union Cup. PIPE-LAYING- Caving - Tunneling - Bell-Holes - ^^M^ R V J C E ' P X P E S Stony Trenches Feathers and Wedges Blasting Rocks and Water Wiped Joints and Cup-Joints The Laying Cast-iron Pipe Derrick Gang Lawrence Air-Pump Wire-drawn Sol- Handling the Derrick Skids Ob- der Weight of Lead Service- Pipe structions Left in Pipes Laying Pipe Tapping Wrought-Iron Mains Ser- in Quicksand Cutting Pipe. vice-Boxes Meter?. HANDSOMELY BOUND IN CLOTH. Sent (post-paid) on receipt of $2.00. Address, BOOK DEPARTMENT, THE ENGINEERING AND BUILDING RECORD. THE HARRISBURG PATENT IMPROVED DOUBLE ENGINE STEEL STEAM ROAD ROLLER. Unequaled in Economy, Efficiency and Workmanship. MANUFACTURED BY FOUNDRY & MACHINE DEPARTMENT, HARRISBURG, PA. BUILDERS OF THE IDE AND IDEAL AUTOMATIC ENGINES, BOTH PLAIN AND COMPOUND. Also Boilers and Tank Work of all Descriptions. CIRCULARS ON APPLICATION. WATER-WASTE PREVENTION: Its Importance and the Evils Due to its Neglect. With an account of the Methods adopted in various Cities in Great Britain and the United States. JBy HENRY C. MEYER, Editor of THE ENGINEERING & BUILDING RECORD. With an Appendix. EXTRACT FROM PREFACE. During the summer of 1882 the Editor of THE SANITARY ENGINEER carefully investigated the methods employed in various cities in Great Britain for curtailing the waste of water without subjecting the respective communities to either inconvenience or a limited allowance. The results of this investiga- tion appeared in a series of articles entitled " New York's Water-Supply," the purpose being to present to the readers of THE SANITARY ENGINEER such facts as would stimulate public sentiment in support of the enforcement of measures tending to prevent the excessive waste of water so prevalent in American cities, and especially the city of New York, which was then suffering from a short supply Numerous requests for information, together with the recent popular agitation in connection with a proposition to increase the powers of the Water Department of New York City with a view to enabling it to restrict the waste of water, have suggested the desirability of reprinting these articles in a more convenient and accessible form, with data giving the results of efforts in this direction in American cities since the articles first appeared, so far as they have come to the author's notice TABLE OF CONTENTS : CHAPTER I. CONDITION OF NEW YORK'S WATER-SUPPLY. Mr. Thomas Hawksley on Advantages of Waste-Prevention ; Condition of Water-Supply in England Thirty Years Ago ; Means Adopted to Prevent Waste in Great Britain; Norwich the First City in Eng- land to Adopt Measures of Prevention ; Lon- don : the Practice There. CHAPTER II. GLASGOW. District Meters Tried as an Experiment -Results of Experi- ments ; Prevalence of Defective Fittings ; Testing and Stamping of Fittings ; Rules Governing Plumbers' Work. CHAPTER III. MANCHESTER. History of Waste-Prevention Measures; Methods of House-to-House Inspection ; Duties 'of In- spectors ; Methods of Testing and Stamping Fittings. CHAPTER IV. LIVERPOOL. Change from Intermittent to Constant Supply ; Method of Ascertaining Locality of Waste by Use of District Meters ; Method of House Inspec- tion ; Method of Testing Fittings. CHAPTER V. PROVIDENCE AND CINCINNATI. Review of Measures to Prevent Water- Waste in the United States prior to 1882 ; Providence, R. I.: Results following the Gen- eral Use of Meters ; Cincinnati: Methods of House Inspection with the Aid of the Water- phone ; Results Attained. CHAPTER VI. NEW YORK. Measures Adopt- ed by the Department of Public Works prior to 1882. CHAPTER VII. GENERAL CONCLUSIONS. Points to be considered in Adopting Measures for Large Cities. APPENDIX. POINTS SUGGESTED IN THE CON- SIDERATION OF VARIOUS METHODS. Water- Waste Prevention in Boston in 1883 and 1884 ; Results Attained ; Waste-Prevention m New York City; Liverpool Corporation Water- Works Regulations ; Glasgow Corporation Water- Works Regulations; Description of Standard Fittings; Penalties for Violations ; Cistern vs, Valve-Supply to Water-Closets in New York City; New York Board of Health Regulations concerning Water-Sup- ply to Water-Closets ; Letters from Water- Works Authorities sustaining the action of the New York Board of Health in Requiring Cistern-Supply to Water-Closets; Extracts from Report of Boston City Engineer on Wasteful Water-Closets; Proposed Water- Rates on Water-Closets in New York ; Reso- lutions of the New York Board of Health endorsing the proposed Water-Pates for Water-Closets; Excerpts from Articles ex- plaining Methods of Arranging Water-Supply to Water-Closets to secure the Minimum Water-Rate in New York (with illustrations). Large $>vo. Bound in Cloth, $1.00. %* Sent post paid on receipt of price. Address, BOOK DEPARTMENT, THE ENGINEERING AND BUILDING RECORD, No. 277 Pearl Street, New York. 0*1* 4.000.000. SQ.y 0s OR260 LINEAL MILES IN USC. The Barber Asphalt Paving Co. IS THE Oldest and Largest Paving Company in the UNITED STATES. It has, up to January i, 1890, laid Asphalt Pavements in Twenty- seven Cities of the United States, on 607 streets, of a length of 260 miles, covering an area of 3,916,574 square yards. No Asphalt Pavement laid by this company in the .United States has ever been replaced by another form of pavement. This company has taken up other pavements, and replaced them with Trinidad Asphalt Pavements to the following extent : WOOD, 459>033 sc l' > r