auger nose, Fig. 51; in either case there is a clack or valve placed inside for the purpose of retaining borings of a soft nature or preventing them from being washed out in a wet 16 Figs. 57, 58, 59. hole. Fig. 59 shows a wad-hook The Crow's Foot, Fig. 55, is crow's foot screwed on in place of Fig. 60. the broken piece; when this is lowered down upon the broken rod, by careful twisting the toe is caused to grip the broken piece with sufficient force to allow the portion below the fracture to be drawn out of the bore-hole. A rough expedient is to fasten a metal ring to a rope and lower it over the broken rod, when the rod cants the ring, and thus gives it a considerable grip; this is often very successful. Fig. 57 is a worm used for the same purpose. A bell-box, Fig. 60, is frequently employed for drawing broken rods; it has two palls fixed at the top of the box, which rise and permit the end of the rod to pass when the box is lowered, but upon raising it the palls fall and grip the rod firmly. A spiral angular worm, similar to Fig. 57, is also applied for withdrawing tubes. Of these withdrawing tools the crow is the safest and best, as it may be used without that intelligent supervision and care absolutely necessary with the worms and wad-hooks, or the bell-box. The boring-rods, Figs. 61, 62, are in 3, 6, 10, 15, or 20 feet lengths, of wrought iron, preferably Swedish, and are made of different degrees of strength according to the depth of the hole Fig. 61. 10' : Fig. 62. for which they are required; they are generally 1 inch square in section at one end is a male and at the other end a female screw for the purpose of connecting them together. The screw should not have fewer than six threads. One of the sides of the female screw frequently splits and allows the male screw to be drawn out, thus leaving the rods in the hole. By constant wear, also, the screw may have its thread so worn as to become liable to slip. Common rods being most liable to accident should be carefully examined every time they are drawn out of the bore-hole, as an unobserved failure may occasion much inconvenience, and even the loss of the bore-hole. In addition to the ordinary rods there are short pieces, varying from 6 inches to 2 feet in length, which are fixed at the top, as required, for adjusting the rods at a convenient height. Fig. 63. Fig. 64. Fig. 65. Fig. 66. Fig. 63 is a hand-dog; Figs. 64 and 65, a lifting dog; Fig. 66, the tillers or handles by which the workmen impart a rotary F motion to the tools. The tillers are clamped to the topmost boring rod at a convenient height for working. Fig. 61, a Fig. 67. top rod with shackle. Fig. 67, a spring-hook. When in use this should be frequently examined and kept in repair. Lining tubes are employed to prevent the borehole falling in through the lateral swelling of clay strata, or when passing through running sand. The tubes are usually of iron, of good quality, soft, easily bent, and capable of sustaining an indent without fracture. Inferior tubes occasion grave and costly accidents which are frequently irreparable, as a single bad tube may endanger the success of an entire boring. Wrought-iron tubes with screwed flush joints, Fig. 68, are to be recommended, but they are supplied brased, Fig. 69, or riveted, Fig. 70, and can be fitted with steel driving collars and Fig. 68. Figs. 69 and 70. shoes. Cast-iron tubes are constantly applied; they should have turned ends with wrought-iron collars and countersunk screws. Fig. 71. Cold-drawn wrought-iron tubes have been used, and are very effective as well as easily applied, but their relatively high cost occasions their application to be limited. Fig. 71 shows a stud-block, which is used for suspending tubing either for putting it down or for drawing it up. It consists of a block made to fit inside the end of the tube, and attached to the rods in the usual way. In the side of the block is fixed an iron stud for slipping into a slot, similar to a bayonet joint, cut in the end of the tube, so that it may be thus suspended. Figs. 72 to 74 show various forms of spring-darts, and Fig. 75 a pipe-dog, for the same purpose. Sometimes a conical plug, with a screw cut around the outside for tightening itself in the upper end of the tube, is used for raising and lowering tubing. Figs. 76 and 77 are of tube clamps, and Fig. 78 tongs for screwing up the tubes. Fig. 79 is of an ordinary form of sinker's bucket. Fig. 80 is a pipe-dolly, used for driving the lining tubes; the figure shows it in position ready for driving. When a projection in the bore-hole obstructs the downward course of the lining tubes, the hole can be enlarged below the pipes by means of a rimer, Fig. 81. It consists of an iron shank, to which is bolted two thin strips, bowed out in to the form of a drawing pen. The rimer is screwed on to the boring rods, and forced down through the pipes; when below the last length of pipe the rimer expands, and can then be turned round, which has the effect of scraping the sides and enlarging that portion of the hole subject to its operation. Fig. 82 is of an improved form of rimer, termed a riming spring. It will be seen that this instrument is much stronger than the ordinary rimer, in consequence of the shank being extended through its entire length, thus rendering the scraping action of the bows very effective, whilst the slot at the foot of the bows permits of its introduction into, and withdrawal from, the tubing. Fig. 80. Fig. 81. Fig. 82. In England, for small works, the entire boring apparatus is frequently arranged as in Fig. 83, the tool being fixed at the end of the wrought-iron rods instead of at the end of a rope, as in the Chinese method. Referring to Fig. 83, A is the boring tool; B the rod to which the tool is attached; D D the levers by which the men E E give a circular or rotating motion to the tool; F, chain for attaching the boring apparatus to the pole G, which is fixed at H, and by its means the man at I transmits a vertical motion to the boring tool. The sheer-legs, made of sound Norway spars not less than 8 inches diameter at the bottom, are placed over the bore-hole for the purpose of supporting the tackle K K for drawing the rods |