Nevertheless, the sewerage system of Paris is conceived and carried out in its general plan with an appreciation of the requirements of modern sanitary science and an intelligent employment of the science of the engineer that are quite admirable. The methods of disposing of the city's refuse in use by many American municipalities, as those of New York and Chicago, are, by comparison, but dull and stupid perpetuation of antiquated traditions. The animated controversy over the great question of Tout à l'égout, "all refuse to the sewer," was not finally settled till 1894, and this method has as yet not been applied to all the quarters of the city, as stated above, but is being gradually extended, and nothing but time seems to be wanting to bring about in this capital a complete solution of one of the most difficult problems of material civilization. The object of the Parisian method is to avoid fouling the Seine in any way, and to utilize all the city's refuse, instead of throwing it away or allowing it to accumulate, a menace to health and a hideous nuisance. By an excellent system of underground conduits, well lighted and ventilated, the sewage and the rain-water are collected, carried by canals and pipes outside the city, and applied, after proper treatment, to the fertilization of certain arid tracts of land farther down the river. The principal agent in this "hygienic transformation of Paris" was the engineer Belgrand, who, at his death, in 1870, had increased the length of the municipal sewers from two hundred and twenty-eight kilomètres in 1860 to six hundred. It has now attained a total of fourteen hundred and twenty-one, representing a capital of a hundred and fifty millions of francs.
The first principle of Belgrand's system was to avoid any discharge from the sewers into the river during its course through Paris. The great main sewer, the collecteur général, of the right bank, called the collecteur d'Asnières, follows the quais from the basin of the Arsenal to the Place de la Concorde, then burrows under the heights of the Batignolles to reach Clichy; the collecteur général of the left bank, which includes the poor little Bièvre, traverses the bed of the Seine by means of a siphon at the Pont de l'Alma and is prolonged by the collecteur Monceau, which passes under the hill of the Place de l'Étoile to join the collecteur d'Asnières. A third collecteur, known as the départemental, or du Nord, at a higher level, receives the drainage of Belleville and Montmartre, and issues from the city by the Porte de La Chapelle to reach the Seine at Saint-Denis. A new siphon, constructed under the Seine in 1895 and 1896, unites the collecteur général of the left bank to the collecteur d'Asnières. The sewage of the Iles Saint-Louis and de la Cité is carried by two other siphons to the collecteurs of the quais of the right and left banks.
A new main sewer, called the collecteur général de Clichy, was commenced in 1896, to supplement those of Asnières and Monceau, become insufficient; this passes under the Avenue and the Rue de Clichy to terminate at the Place de la Trinité. The prolongation of the line of the Orléans railway to the Quai d'Orsay, by means of a tunnel, has necessitated a very important modification of the sewers of the left bank of the river, which has had much to do with the lengthening of the work of excavation which has so greatly annoyed the dwellers on this side of the river in 1898 and 1899. It was understood that this excavating was to be done entirely underground, whereas it has blockaded many of the narrower streets, and even when it tunnels it contrives to raise the street level about a mètre and substitute a wooden floor, as along the Quai Voltaire. It is stated that this work will cost the railway company not less than five million francs.
The diameter of the vault of the égouts collecteurs varies between four and six mètres; that of the égouts secondaires from two mètres to three mètres, seventy centimètres; that of the égouts ordinaires, including ten varieties, from one mètre to one mètre, seventy-five. The size the most in use has a diameter of one mètre, forty. The problem of purifying and utilizing the contents of the sewers, which were provisionally discharged into the Seine at Saint-Denis and at Asnières, occupied the attention of the municipality from the period of the establishing of the collecteurs, but the vigorous local opposition which was encountered greatly delayed the carrying out of these projects. Consequently, the purification of the river is not yet complete. On the sandy and arid plain of Genevilliers, situated in the first loop of the Seine, beyond Clichy, the experiment of fertilizing with this drainage was commenced in 1869. At present, the ground thus under cultivation includes some seven hundred and ninety-five hectares,—about two and a half acres each,—of which six belong to the city of Paris and constitute the model garden. The remainder is held by private individuals, who pay a rental of from four to six hundred francs the hectare. The distribution of the sewage is effected by agents of the administration in regular rotation, in three zones. In 1896, each hectare absorbed thirty-seven thousand and sixty-seven cubic mètres. All varieties of vegetables are grown, and this land, on which were raised formerly only meagre crops of rye and potatoes, is now a flourishing garden.
A second agricultural establishment at Achères, farther on, on both sides of the Seine, was inaugurated in 1895, the larger portion of which is held by individuals, but as each hectare of land can absorb not more than forty thousand cubic mètres annually, it has been found necessary to seek additional champs d'épuration. These have been secured by the municipality at Méry and les Gresillons and in their neighborhood, still farther westward, and the completion of these is promised for the summer of 1899. In the model garden of Asnières, all varieties of culture are practised, the sewage is carried in trenches into the cultivated land in such a manner as to bathe only the roots of the plants. The extremely winding course taken by the Seine west of Paris renders it necessary for the conduits conveying this drainage to cross the river three times before reaching Achères, as may be seen by reference to the map. From the usine elévatoire of Clichy it is carried under the Seine by a siphon, four hundred and sixty-three mètres in length; the aqueduct crosses the river again near the usine de Colombes, opposite Argenteuil, on a steel bridge, and again near Herblay, by another siphon. In 1897, on the total surface, a thousand hectares, under cultivation, there were spread seventy million cubic mètres of sewage.
After many and long debates, carried on both in the Conseil Municipal and the Chamber of Deputies, the much-discussed question of Tout à l'égout was disposed of by a law passed on the 10th of July, 1894, by which the proprietors of all houses situated in streets provided with a public sewer were required to make connections with this and drain into it all the refuse of their cabinets d'aisances. This connection was to be made within the space of three years, and a proportionate tax for this privilege was laid upon each dwelling. But the streets in which there are no public sewers,—including those private streets, impasses, and cités which the municipality considers as the property of individuals, and for which it provides neither policemen nor street-cleaners,—and those buildings in which this connection has not been made, still furnish occupation for those nocturnal vehicles the mere thought of which drives the careful citizen to close his windows. In the seventeenth century, this nocturnal agent was known as Maître fy-fy et des basses-œuvres, and he fulfilled his task by carting his material to one of the public dumping grounds and there discharging it. Many of the now picturesque sites of the city owe their characteristics to these eminences of refuse,—the Buttes of the Rues Meslay and Notre-Dame-de-Nazareth, Bonne-Nouvelle, des Moulins, the labyrinth of the Jardin des Plantes. "The voirie of Montfaucon," says M. Strauss, "with its infected basins, its pestilential reservoirs, its charnier and its gibbet, was a cause of shame and anxiety to several quarters of Paris; even after being transferred from the Faubourg Saint-Martin to the foot of the Buttes Chaumont, it was an object of horror and disgust. An army of rats garrisoned the charnier, whilst the basins overflowed with rottenness. This horrible establishment had its clientèle; in 1832, the Préfet de Police, M. Gisquet, found, according to the account of M. Mille, a hideous thing,—individuals who, in the midst of these lakes, fished up again the dead fish.
"In 1848, this notorious laystall was installed in the forest of Bondy, where it has undergone various transformations; for many years the basins were encumbered with a stock but very slightly appetizing; to reduce these mountains of refuse to industrial products was a very serious undertaking. After being, by slow desiccation by drying in the air and grinding, transformed into a fertilizer called poudrette, they are subjected to various chemical processes; there is extracted from them sulphate of ammonia, etc. The odors which are disengaged during these operations, while not injurious to the health of man, are not of those which leave public opinion indifferent; the girdle of insalubrious establishments which immediately surrounds Paris, individual dépotoirs, private voiries, manufactories of fertilizing materials, is no less menacing than disgraceful.
"A single establishment is an exception to this rule, it is the dépotoir of La Villette, in the neighborhood of the Marché aux bestiaux. It would never be thought, from its appearance, that it was the nightly rendezvous of the most infectious scavengers' carts that traverse Paris. A coquettish garden, of a surprising greenness, all flowery and perfumed, charms the eyes; the receiving cisterns conceal themselves under vaults that do not reveal their secret to the first comer. The basin of the water of the Ourcq has the most innocent air in the world, and the return-pumps reveal nothing.
"All night long, the dépotoir is visited by vehicles, two or three hundred in number, which arrive in single file, with a mysterious heaviness, to discharge themselves in the cisterns. What a discharge! a thousand to twelve hundred cubic mètres—of matter!