292 REPOET 



coupling, and are entirely stiff tbroiighout. The brancli, li t, may also 

 be stiff', but in case tbe arms are rigid it will generally be preferable 

 that this main be flexible throughout, or at least in one of its junct- 

 ures, h. Any or all of the three tubes forming the fork may be made en- 

 tirely elastic by using hose-tubing with coiled or straight springs on 

 the outside or the inside of the same. A straight i)iece of spring metal 

 is generally preferable from being simpler and cheaper. In «ase any 

 peculiar curve or position is to be given to the hose-tubes it may simi- 

 larly be done by a rod having elastic or inelastic properties. To pre- 

 vent such a rod from sliding out of its proper position in the tube it 

 should be secured in at least one i)oint. In Plate XLIX Fig. 5 is a 

 sectional view of a fork showing how the rod may be inserted and fast- 

 ened ; t is the insertion of the main, and j represents the arms or their 

 coupling-pieces, while y is the angle coupling. The rods to extend into 

 the branches are indicated by s c. In this case they are shown with 

 the one end s free while the two cross in the angle, and each has its 

 other end riveted or soldered at c, in a hole drilled through the walls 

 of the passage. Where the central piece is a casting this method is 

 sometimes the best, but in Plate XXXIX, ¥i^. 4, a single rod, repre- 

 sented by the broken line s s, extends around through both arms acting 

 as a V-spring. Where the middle coupling is made by joining pieces of 

 pipe [Ib.^ Fig. 5.], a rod of such shape is easily inserted before the parts are 

 united. Other variations in the construction of these same devices can 

 be thought out by any practical mechanic, and hence such need not be 

 described here. When long sections of hose are used, where they tend 

 to sag, bend, or kink as along the more or less horizontal supporting 

 bar or frame, or in the nozzle-bearing arms, inside rods should be in- 

 serted as supports. They are also of value to hold hose sections at 

 any particular curve desired. The flexible sections or joint-sheaths, 

 e e, are easily made by any planter and require no special mechanical 

 skill. The hose segment should fit tight upon the metal one and be held 

 firmer by a single band or wire wrap, o, twisted or clinched tight around 

 it. The flexibility of hose-coupled joints allows no breakage of the 

 pipes, by permitting only tensile strain without lateral strain, rendering 

 repair seldom necessary, whereas with stiff' joints the segments are very 

 liable to bend or break, especially at their ends, where weakened by the 

 thread cut for insertion in the screw-couplings. Stifl* systems require 

 the pipe to be several times heavier to prevent bending and breakage. 

 Thus, aside from the economy in having much less weight, the lighter 

 tubing costs less ; and this reduction in weight and price allows the 

 use of brass tubes, which are much i)referable to heavy iron pipes that 

 rust and are otherwise objectionable. Also, on this plan, even light zinc, 

 tin, or other sheet-metal sections or angle-pieces which are not soldered 

 stiffly together, but are easily separated or joined by any planter, can 

 be emjfloyed. The lightest and cheapest apparatus can be made in 

 these ways, and with the least amount of labor and skill in construct- 



