ace de l'Etoile
to join the collecteur d'Asnieres. A third collecteur, known as the
_departemental_, 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 general of the
left bank to the collecteur d'Asnieres. The sewage of the Iles
Saint-Louis and de la Cite 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 general de Clichy, was commenced
in 1896, to supplement those of Asnieres and Monceau, become
insufficient; this passes under the Avenue and the Rue de Clichy to
terminate at the Place de la Trinite. The prolongation of the line of
the Orleans 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 metre 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.

[Illustration: UNDERGROUND PARIS: LICENSED RAT-CATCHER IN A SEWER.

After a design by G. Amato.

Henri Dayre: Chasseur de rats de la Ville de Paris, fournisseur de
toutes les Societes de France et de l'Etranger.]

The diameter of the vault of the _egouts collecteurs_ varies between
four and six metres; that of the _egouts secondaires_ from two metres to
three metres, seventy centimetres; that of the _egouts ordinaires_,
including ten varieties, from one metre to one metre, seventy-five. The
size the most in use has a diameter of one metre, forty. The problem of
purifying and utilizing the contents of the sewers, which were
provisionally discharged into the Seine at Saint-Denis and at
Asnieres, 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