APPENDIX B. 



173 



dinary " walking-beam " of wood, driven by an engine of small horse- 

 power. 



The beam rises and falls continually over the mouth of the well, 

 the chain which suspends the tool passing over the end of the beam, 

 being so arranged that it can be let out as the hole deepens, at the 

 same time lifting the tool or drill and allowing it to drop with 

 measured stroke on the rock, which is thus gradually drilled out. 

 A workman sits at the mouth of the well, having the pole grasped by 

 his hands, and after every stroke the poles are slightly turned so as 

 to turn the drill which is working on the bottom, thus keeping the 

 well true and circular in shape. 



While the well is in process of boring, the tools are frequently re- 

 moved and the sand pump introduced to remove the loose matter 

 from the bottom of the well, which is done by means of a suc- 

 tion valve. The sand pump removes all the ground rock sand, and 

 takes up at times stones an inch or more in size. In commencing 

 the well, a strong wooden box 8 inches square, made from 2-inch 

 plank, is driven down into the ground, say from 14 to 16 feet. 

 Inside of this, an 8-inch iron tube or casing is put down as fast 

 as the alluvial or drift material overlying the rock formation is bro- 

 ken up by the drill and taken out by the sand pump ; this continues 

 until the solid rock is reached. 



At this point, considerable care should be taken that the opening 

 into the rock is perfectly round and well finished by the drill ; for 

 the casing should beset so firmly in the rock-as to prevent any sand 

 or gravel from running in under the tube, and thus getting in on 

 top of the drill and endangering its becoming fastened in the well. 



The rock-drilling now commences and continues to the depth 

 to which it is proposed to sink the well. After the drilling is 

 done, the sides of the well are smoothed off with a tool called a 

 reamer. 



In most of the salt wells on the Saginaw River an offset is placed 

 in the well at a short distance above the lower sand rock. Below the 

 offset the size of the well is lessened half an inch in diameter. 



On this offset is made the so-called rock-packing, the hole being 

 drilled bevelling so as to receive a tightly-fitting iron collar or fun- 

 nel-shaped piece of metal. A tube corresponding to the size of the 

 upper part of the well is made to rest on this rock-packing as the 

 offset, and runs to the top of the well; in this way, all the weak 



