=Sill Cocks.=--As a means of attaching garden hose or lawn sprinklers, sill cocks are placed on the side of the building at any place convenient for their use. Fig. 75 illustrates the method of attaching the cock to the water supply. Fig. 76 shows in cross-section its mechanical arrangement. The part _A_ is screwed into the water supply, and _B_ furnishes the hose attachment. The valve is operated the same as any other compression valve. In Fig. 75 the cock is shown at _A_ with a garden hose attached. The pipe to which _A_ is attached passes into the basement and connects to the water supply. The stop-cock _B_ is used to shut off the water. When the stop-cock _B_ is closed, _A_ should be opened, so that the pipe will drain. If this is neglected during freezing weather, the pipe is apt to freeze and burst. =Valves.=--The distinction between a cock and a valve is not at all definite. Custom has determined that in certain places a cock shall stop the flow of a liquid but in another place, perhaps of a similar nature, a valve shall accomplish the same purpose. The chief distinction between a cock and a valve is that of its external form. In Figs. 77, 78 and 79 are three examples of valves that are very generally used on pipes carrying any kind of fluid. The valves are shown in cross-section to display the arrangement of the mechanism. [Illustration: FIG. 77.--Cross-section of globe valve with detachable valve disc.] [Illustration: FIG. 78.--Cross-section of angle globe valve.] [Illustration: FIG. 79.--Cross-section of gate valve.] Fig. 77 is an example of the common _globe-valve_. The name was originally intended to define a valve the body of which was in the form of a globe. The hand-wheel _H_, attached to the screw-stem _S_, raises the valve _A_ when desired. The valve makes close contact with the seat _C_, by means of a composition rubber disc _B_. The disc _B_ may be renewed when worn out as in the case of the radiator valve already described. Fig. 78 represents an _angle globe-valve_. In general construction it is quite similar to Figs. 14 and 15, but the valve _V_ in this case is a cone-shaped piece of brass, which makes a seat in a depression provided for it. The valve _V_ and the seat are formed as desired and then ground into contact with emery dust or other abrasive material, to assure a perfectly tight joint. When this valve becomes worn and begins to leak, it may be repaired by regrinding, but such work requires the services of a pipe-fitter. The tendency of modern practice is to use valves with the detachable discs, such as that of Fig. 77, because they are easily repaired.