Appendix-Street Pavements. sensitive nerves is a frequent result from the noise and vibration of stone-paved streets. Fonssagrives, Professor of Hygiene, at Montpelier, says: I cannot consider such perpetual vibration of the nerves as harmless, even for those who have been born and bred in the midst of noise. It is a very general cause of erethism, and to it must be ascribed the prevalence of nervous temperaments in large towns. With hysteria (from noise), at eight years of age, what shall be said of invalids? The noise of a stone pavement also means wear and expense. Over one hundred and eight thousand tons of granite pavement are ground into dust each year in the streets of London. Macadamized streets are less objectionable from noise, than where granite is used, but they are little else than dust-mills. No description is necessary of the misery of the dwellers along a macadamized street. Extremely filthy in wet weather, they are intolerable in dry weather. In all large cities of Europe, stone has been abandoned for paving, and smooth, quiet surface is being laid. ASPHALT. Asphalt is being extensively substituted for stone. It has been thoroughly tested, and, whether laid in blocks, or compressed, with satisfactory results. The most serious objection to it is its cost and smoothness, the latter confining its use to grades of one foot in fifty. It is impervious to water, easily cleaned and noiseless. It may be tunnelled for laying water or gas pipe, or removed and replaced without showing the cut. It is non-absorbant. Briefly stated, asphalt paving is composed of crushed limestone and Trinidad asphaltum, subjected to a pressure of three thousand pounds to the square inch, at a temperature of two hundred and fifty degrees Fahrenheit. It has been in use twelve years. In 1887, over one hundred and sixty-five lineal miles of it were laid in various cities of the United States. Appendix-Street Pavements. WOOD PAVEMENT. In the West, the expense of stone and asphalt has by necessity thrown the choice to other material. Wood pavement of several kinds has been thoroughly tested: First, the Nicholson, and other patented devices; next, the cedar block. The Nicholson, and similar patents have been entirely abandoned, for purely economic reasons. The cedar block has not proved so successful as expected. The sub-base of plank is laid when green, coated with tar; the blocks are laid also when green, with the transverse joints filled with gravel and tar; the upper face of the block faced with tar and sand. Frequently the placing of this paving, follows close upon the closure of gas, sewer, and water-main trenches, without settlement, causing subsequent depression and crevices in the pavement for the admission of water and filth. In this latitude, the upheaval by frost is considerable. In the Summer the blocks crack from sun-heat, thus admitting water to the wood cells and fibre, and hastening decay. When wet, the blocks are slippery, and on heavy grades give uncertain foothold to horses, thereby endangering life and limb. As cedar blocks are usually laid, they quickly become a mass of decaying vegetable matter. Absorption increases with disintegration, until they become also fully saturated with the filth of the street. Tarring of the green boards upon which they are placed, adds to the objection; it closes the cells, prevents the escape of moisture, hastens fermentation, and soon the wood becomes a mass of "dry-rot." A well known physician of Chicago, declares that "on a warm morning, after a shower, on streets paved with cedar blocks, the affluvia arising from the fermentation and decomposition of the blocks can be actually tasted, and be seen rising like a fog, and laden with disease germs, which in dry, hot weather are driven into dwelling houses, causing diphtheria and other diseases, to an alarming extent." To secure a more permanent and durable foundation for these blocks, cement is sometimes used instead of boards, which only increases the sanitary objections. The cement holds the accumulated filth and moisture beneath the blocks, thereby hastening and increasing fermentation and decay, and rendering more noxious the Appendix-Street Pavements. affluvia from the fermenting mass. Such a base for wood paving should never be permitted in any community having proper regard to sanitary conditions. In the city of Basle, wood paving was tried on one street and abandoned as unsatisfactory. Eighteen months ago, the roadway over the Goethe bridge in Hanover, Germany, was paved with a new material called India Rubber. Since then, an entire street has been paved with it in that city, and it is being laid in the streets of Berlin and Hamburg. It is reported to combine great elacticity with the hardness of stone, noiseless, more durable than asphalt, not slippery, and not affected by temperature. BRICK. Public attention is turning to brick. It is no innovation. In the Netherlands of Europe, highways have been paved with brick for more than half a century. In West Virginia it has been used for sixteen years, in the city of Charleston. In Bloomington, Illinois, it has been used fourteen years. Decatur, Illinois, has nearly all her streets paved with it. In Ohio it has been adopted in several cities, and its mileage is increasing every year. Dr. James E. Reeves, the eminent sanitarian, and late President of the American Public Health Association, and Secretary of the West Virginia State Board of Health, writes: “It affords me much pleasure to bear testimony to the superior quality of the street paving, which has been done in Wheeling with vitrified blocks, or artificial granite, as I am in the habit of calling the blocks. Chapline street -the busiest street in the city-was laid in the Fall of 1883, since which time every possible test has been made of the work. The line of the horse car track shows even to this date not the least wear or uneveness, a condition which proves the nature of such paving. It is not only durable, but smooth as the best of the sidewalks, cleanly, comparatively noiseless and easy to the feet of horses and protective of all wheeled carriages, In a sanitary point of view it is absolutely priceless. No other material in use for street paving can be compared with it for cleanliness, Beside it is the easiest to keep clean and in good repair." Clay is the ore of alluminum, and when properly mixed and vitrified, becomes an igneous rock, unaffected by heat, water or frost. Appendix-Street Pavements. It has a greater resisting power against shock than granite, is homogeneous, slightly elastic, has no grit which will bite steel or iron; will neither act upon, nor be acted upon by horses' shoes; has a more perfect bearing than stone; can be laid more compact; is noiseless, dustless, non-absorbent, and therefore healthful. The brick used are of various forms. In eastern cities they are of the common, oblong form. Later devices mould them with onethird the base one-quarter of an inch thicker than the upper twothirds, as shown in the diagram. A sub-base of properly rolled sand is laid on the roadbed, over which is laid vitrified tile blocks eight inches square, and two inches thick. Over the tile is thrown a thin stratum of fine, clean sand, upon which the brick are placed, with the base in con space of one-half inch to be filled with sand. tact, thus leaving a This furnishes a dur able, smooth pavement, yet with good foot hold for horses; easily cleaned; and nearly, if not quite impervious to water. For repairs, only so much area as actually required, need be removed. It is quickly replaced and ready for the trafic without delay. REQUISITES OF PAVEMENT. The requisites of pavement, and the material, are here given in the order of quality: The conclusions are based on the best and most extensive authorities published. 1. Economy.-The best is the cheapest. For cost; asphalt, granite, brick, cedar blocks. 2. Rapidity of Construction.-Asphalt, granite, cedar blocks, brick. 3. Facility for Removal and Replacemement.-Brick, asphalt, granite, cedar blocks. Appendix-Street Pavements. The 4. Durability.--Brick, granite, asphalt, cedar blocks, macadam. deterioration of cedar blocks, resulting from fermentive decay, is greater from the bottom upward, than from the wear of traffic. Blocks that had been laid three years, taken from a heavy grade on the streets of Des Moines, leading to the capitol, were saturated with sulphuretted hydrogen, and showed nearly entire destruction of the fibre from the bottom upward. When thoroughly dried, the blocks disintegrated. 5. Firmness for Foot-Hold. -- Brick, asphalt, granite, cedar blocks. Observations made in Paris, to discover the liability of horses to fall on pavements, extending over eighty-one thousand miles travelled, and eight hundred thousand horses, showed one fall to five hundred and eighty-three miles on asphalt, four hundred and thirteen miles on granite, and two hundred and seventy-three on wood. 6. Smoothness.-Asphalt, brick, cedar blocks, stone. The smoother a pavement, the easier kept clean; the less noise; the less wear of vehicles; the greater pleasure to the rider or driver; the greater comfort to the invalid; and the greater economy of horse power. The latter is an item of considerable importance. Rudolph Hering has demonstrated that if one horse can move a load on a level iron rail, it will require one and two third horses to move the same on asphalt, three and one third on best granite blocks, five on ordinary granite blocks, seven on good cobble-stone, thirteen on bad cobblestone, twenty on ordinary earth road, and forty on sand road. 7. Cleanliness.--Experience has shown that stone pavement cannot be kept clean; cedar blocks may be, on the surface. Asphalt may be kept perfectly clean. Brick afford little or no lodgement for filth. 8. Imperviousness.--From a sanitary stand-point, imperviousness to moisture is an all important requisite of street pavement. Every sanitarian is cognizant of the danger from soil contamination and pollution; that a filthsodden soil has a bad influence upon health by the effluvia emanating therefrom. The constituents of street filth are multifarious-excreta and urine of animals, garbage, kitchen water, house slops, solid and liquid human excreta. With a pervious pavement this foul mess is washed and soaked into the soil, exposing wells to pollution, and dwelling-houses to poison by “ground air.” The logical deduction is, that is the best pavement which is most impervious to moisture, from which water passes away the quickest with the least absorption or percolation, and which can be the most thoroughly and easily cleaned. A careful investigation of all the literature accessible (quite extensive), leads me to the firm conclusion that asphalt is the best, and brick the second best material for sanitary street paving. It is pertinent here to say that the sanitary and economical value of pavement consists in preserving it intact as first placed. Sewer |