Up to this point there is good reason to believe that the modern practice is similar to, if not identical with, that anciently used; but in the complete absence of evidence, documentary or otherwise, we cannot conjecture how the old well-sinkers proceeded in subsequent stages. We surmise, however, that, given sufficiency of time, they were possessed of the requisite patience and skill to overcome all ordinary obstacles—as has been the case for generations in China—and it is probable that the percentage of wells abandoned was not greater than it is at the present day in countries where well-boring has become an art, carried out by means of scientifically designed machinery. The second part of the modern operations is conducted with an ordinary percussion hand-boring outfit of European manufacture. As the method of boring with this type of rig is essentially the same all over the world, we only propose to describe it in brief. The proceedings commence with the erection of a timber framework, or derrick, immediately over the mouth of the pipe; at the summit of the derrick is a pulley, over which passes the rope or chain which connects on one side with the drum of the winch, and from the end of which, on the other side, are suspended the actual tools with which drilling is continued. The boring-rod is made up to the required length by screwing together a number of 10-foot sections, the terminal length being a shorter rod fitted with a chisel, auger, or sand-pump, according to the work in hand. The rate of progress depends to a great extent on the rapidity with which the blows of the chisel are delivered. This, of course, varies considerably, depending on the depth of the well and consequent weight of the rods in use. Where the weight is great and the formation sticky, the rods have to be lifted by means of the winch, and not more than two or three blows a minute can be struck. When the rods are light or working freely, as, for instance, when drilling in sandstones, the winch can be dispensed with, and the necessary motion conveyed by means of a lever actuated by a number of men. In this way progress can be very much accelerated, as many as twenty or twenty-five blows being delivered per minute. At the best, however, the method of drilling by percussion with a solid rod is necessarily slow, owing mainly to the fact that the terminal tool cannot be changed or withdrawn without the entire length of rod being taken to pieces. It is seldom, therefore, that a well of 120 to 150 metres is completed in less than five months, and the average time taken is more like nine months or a year.