Digging the sewerage of Paris was no small task. The last ten centuries have toiled at it without being able to finish, any more than they could finish Paris. The sewer, in fact, receives all the counterstrokes of the growth of Paris. It is in the ground a species of dark polypus with a thousand antennæ, which grows below, equally with the city above. Each time that the city forms a street, the sewer stretches out an arm. The old monarchy only constructed twenty-three thousand three hundred metres of sewers, and Paris had reached that point on Jan. 1, 1806. From this period, to which we shall presently revert, the work has been usefully and energetically taken up and continued. Napoleon built--and the figures are curious--four thousand eight hundred and four metres; Charles X., ten thousand eight hundred and thirty-six; Louis Philippe, eighty-nine thousand and twenty; the Republic of 1848, twenty-three thousand three hundred and eighty-one; the present government, seventy thousand five hundred: all together two hundred and twenty-six thousand six hundred metres, or sixty leagues, of sewer,--the enormous entrails of Paris,--an obscure ramification constantly at work, an unknown and immense construction. As we see, the subterranean labyrinth of Paris is, at the present day, more than tenfold what it was at the beginning of the century. It would be difficult to imagine all the perseverance and efforts required to raise this cloaca to the point of relative perfection at which it now is. It was with great trouble that the old monarchical Provostry, and in the last ten years of the eighteenth century the revolutionary Mayoralty, succeeded in boring the five leagues of sewers which existed prior to 1806. All sorts of obstacles impeded this operation; some peculiar to the nature of the soil, others inherent in the prejudices of the working population of Paris. Paris is built on a stratum strangely rebellious to the pick, the spade, the borer, and human manipulation. Nothing is more difficult to pierce and penetrate than this geological formation on which the marvellous historical formation called Paris is superposed. So soon as labor in any shape ventures into this layer of alluvium, subterranean resistances abound. They are liquid clay, running springs, hard rocks, and that soft and deep mud which the special science calls "mustard." The pick advances laboriously in the calcareous layers alternating with very thin veins of clay and schistose strata incrusted with oyster-shells, which are contemporaries of the Pre-Adamite oceans. At times a stream suddenly bursts into a tunnel just commenced, and inundates the workmen, or a slip of chalk takes place and rushes forward with the fury of a cataract, breaking like glass the largest supporting shores. Very recently at La Villette, when it was found necessary to carry the collecting sewer under the St. Martin canal without stopping the navigation or letting off the