There is also a facility in taking turns out of the hose, which no other but a swivel joint affords. By slackening a single turn any twist may be taken out, without undoing the joint or stopping the engine, while, from the number of turns required to close the joints, there is no chance of the screw being by any accident undone. In order to prevent the threads from being easily damaged, they should be of a pretty large size, not more than five or six to the inch. For the same reason also the thread should be a little rounded. As it sometimes happens that the screws are damaged by falling on the street, or by heavy bodies striking them, whenever the hose have been used the joints should be tried by a steel gauge-screw, to be kept for that purpose. This ought to be particularly attended to, as, on arriving at a fire, it is rather an awkward time to discover that a joint has been damaged, while the delay thus occasioned may be attended with very serious consequences. _Four Bundles of Sheepskin and Lay-cord._--These are simply four or five stripes of sheepskin, each about three or four inches broad. When a leak occurs in a length of hose which cannot be easily replaced at the time, one or more pieces of sheepskin are wrapt tightly over the leak and tied firmly with a piece of cord. This is but an indifferent method of mending, but I do not know of any other which can be so readily applied with the same effect. If another length of hose can be substituted for the leaky one it is better to do so; but that is not always at hand, nor does it always happen that time can be spared for the purpose. _Four Lengths of Suction-pipe._--These are generally made of leather, riveted tightly over a spiral worm of hoop-iron, about three-quarters of an inch broad, a piece of tarred canvas being placed between the worm and the leather. They are usually made from six to eight feet long, with a copper strainer screwed on the farther end, to prevent as much as possible any mud or dirt from getting into the engine with the water. It is of advantage to carry four lengths of suction-pipe, as they can be joined to reach the water; if one is damaged the others will still be serviceable. The suction-pipes are more troublesome to rivet than the common hose, and are done in the following manner:--After the joints are fixed on the spiral worm, and it is covered with the tarred canvas, an iron mandrel longer than the worm is put through it, the edge being rounded to the circle of the inside of the worm. The projecting ends of the mandrel are supported to allow the worm to lie quite clear. One end of the mandrel has a check, that the brass joint may not prevent the worm from lying flat on the mandrel. The leather is then put over the worm, and the rivets being put into one side, a small thin mandrel is laid over the canvas and the rivets struck down upon it. If the small mandrel be not used the heads of the rivets are apt to lie unequally on the worm.