THE requisites for water-closets are: (1) simplicity ; (2) quickness and thoroughness of flushing; (3) freedom from all unscoured parts; (4) economy in construction and water consumption; (5) compactness and convenience of form; (6) amplitude of standing water in the bowl; (7) accessibility and visibility of all parts, including trap; (8) smoothness of material; (9) strength and durability of construction; (10) facility and reliability in jointing; (11) security against evaporation and siphonage; (12) ease and convenience of flushing; (13) noiselessness in operation; (14) neatness of appearance.

"The pan closet must be discarded, because it violates every one of the above requirements.

"The valve and plunger closets must be discarded, because they violate all but the sixth and twelfth requirements.

"The ordinary so-called long and short hoppers are to be rejected, because they violate the second, third, fourth, sixth, tenth, eleventh, twelfth and thirteenth requirements. There is no standing water in their bowls to receive and deodorize the soil, so that they are constantly fouled. A preliminary flush is sometimes arranged to partially obviate this trouble, but this contrivance is not to be relied upon. The method of connecting the common hopper with the soil-pipe is usually defective; the seal is too shallow to withstand even a slight evaporation and siphonage, and they are exceedingly noisy in operation.

"All closets which depend upon a double trap violate rules 1, 4, 7, 11 and 13.