[Illustration:  GIRAL’S AUTOMATIC SIPHON.]

The storing up of the water permits of irrigating a much greater area of land, and has the advantage of allowing the watering to be effected intermittingly, this being better than if it were done continuously.  But this mode of irrigating requires assiduous attention.  It is necessary, in fact, when the reservoir is full, to go and raise the plug, wait till the water has flowed out, and then put in the plug again as accurately as possible—­a thing that it is not always easy to do.  The work is a continuous piece of drudgery, and takes just as much the longer to do in proportion as the reservoir is more distant from one’s dwelling.  In order to do away with this inconvenience, Mr. Giral, of Langogne (Lozere), has invented a sort of movable siphon that primes itself automatically, however small be the spring that feeds the reservoir in which it is placed.  The apparatus (see figure) consists of an elbowed pipe, C A B D E, of galvanized iron, whose extremity, C, communicates with the outlet, R, where it is fixed by means of a piece of rubber of peculiar form that allows the other extremity, B D E, to revolve around the axis, K, while at the same time keeping the outlet pipe hermetically closed.  This rubber, whose lower extremity is bent back like the bell of a trumpet, forms a washer against which there is applied a galvanized iron ring that is fixed to the mouth of the outlet pipe by means of six small screws.  This ring is provided with two studs which engage with two flexible thimbles, K and L, that are affixed to the siphon by four rivets.  These studs and thimbles, as well as the screws, are likewise galvanized.  Between the branches, A B D E, of the pipe there is soldered a sheet of galvanized iron, which forms isolatedly a receptacle or air-chamber, F, that contains at its upper part a small aperture, b, that remains always open, and, at its lower part, a copper screw-plug, d, and a galvanized hook, H.

In the interior of this chamber there is arranged a small leaden siphon, a b c, whose longer leg, a, passes through the bottom, where it is soldered, and whose shorter one, c, ends in close proximity to the bottom.  Finally, a galvanized iron chain, G H, fixed at G to the bottom of the reservoir, and provided with a weight, P, of galvanized iron, is hooked at H to the siphon and allows it to rise more or less, according as it is given a greater or less length.

From what precedes, it will be seen that the outlet is entirely closed, so that, in order that the water may escape, it must pass into the pipe in the direction, E D B A C.