=Yard Closets.=--In many old houses the water-closet accommodations are placed in the yard. There are two forms of these yard closets commonly used--the school sink and the yard hopper. The _school sink_ is an iron trough from five to twelve or more feet long, and one to two feet wide and one foot deep, set in a trench several feet below the surface with an inclination toward the exit; on one end of the trough there is a socket fitted with a plug, and on the other a flushing apparatus consisting simply of a water service-pipe. Above the iron trough brick walls are built up, inclosing it; over it are placed wooden seats, and surrounding the whole is a wooden shed with compartments for every seat. The excreta are allowed to fall into the trough, which is partly filled with water, and once a day, or as often as the caretaker chooses, the plug is pulled up and the excreta allowed to flow into the sewer with which the school sink is connected. These school sinks are, as a rule, a nuisance, and are dangerous to health. The objections to them are the following: (1) The excreta lies exposed in the iron trough, and may decompose even in one day; and it is always offensive. (2) The iron trough is easily corroded. (3) The iron trough, being large, presents a large surface for adherence of excreta. (4) The brickwork above the trough is not flushed when the school sink is emptied, and excreta, which usually adheres to it, decomposes, creating offensive odors. (5) The junction of the iron trough with the brickwork, and the brickwork itself, is usually defective, or becomes defective, and allows foul water and sewage to pass into the yard, or into the wall adjacent to the school sink. By the Tenement House Law of New York, the use of school sinks is prohibited even in old buildings. [Illustration: FIG. 29. SCHOOL SINK AFTER SEVERAL MONTHS' USE. (J. SULLIVAN.)]