434 BORING 



of tin, opal; oxido of iron, bottle green and yellow; oxide of manganese, violet; 

 oxide of nickel, pale emerald green. The white oxides impart no colour to it by 

 themselves. In the fusion of metals, borax protects their surface from oxidisement, 

 and oven dissolves away any oxides formed upon them ; by which twofold agency it 

 becomes an excellent flux, invaluable to the goldsmith in soldering the precious 

 metals, and to the brazier in soldering copper and iron. 



Borax absorbs muriatic and sulphurous acid gases, but no others, whereby it be- 

 comes, in this respect, a useful moans of analysis. 



The strength or purity of borax may bo tested by the quantity of sulphuric acid 

 requisite to neutralise a given weight of it, as indicated by tincture of litmus. 



When mixed with shellac in the proportion of one part to five, borax renders that 

 resinous body soluble in water, and forms with it a species of varnish. 



The applications of borax in the manufacture of enamels, glazes, and of glass, will 

 bo noticed in the articles devoted to the consideration of those special industries. 



BORING. Whether for the purpose of searching for coal or other minerals, or 

 for obtaining water for the supply of towns or for land irrigation, the import- 

 ance of boring as a branch of mining science is so important as to command careful 

 consideration in a work of this description. 



Under the head of ARTESIAN WELLS, the various physical conditions under which 

 water may bo obtained by means of boreholes, have been described. It is now pro- 

 posed to give an account of the different modes of prosecuting boreholes, and to refer 

 to the purposes, other than the finding of water, for which the science of boring is 

 resorted to. 



It may be stated generally, that beyond the question of water supply, the boring of 

 holes is chiefly carried out with the object of proving the existence, or otherwise, of 

 rocks or minerals of more or less value. Whilst in putting down holes for the discovery 

 of water, a simple hole, in a firm and durable condition, is all that is required, in the 

 proving of minerals it is very important that the result of the borings should indicate 

 very accurately the character and section of the strata passed through. The extent 

 to which this end has been accomplished will be hereafter referred to. 



Boring for water appears to have been in use from the earliest periods, in Egypt 

 and in Asia. In many of the desert tracts there are remains of borings, which served, 

 evidently at one period, to supply the wants of extensive populations which once in- 

 habited those now deserted regions. In the ' Guide du Sondeur,' by M. J. De'gousse'e, 

 we find it stated, with reference to China : ' There exists in the canton of Ou-Tong- 

 Kiao many thousand wells in a space of ten leagues long by five broad. These 

 wells cost a thousand and some hundred tae'ls (the tae'l being of the value of 6s. 6d.), 

 and are from 1,500 to 1,800 feet deep, and about 6 inches in diameter. To boro 

 these wells, the Chinese commence by placing in the earth a wooden tube of 3 or 

 4 inches diameter, surmounted by a stone edge, pierced by an orifice of 5 or 6 inches ; 

 in the tube a trepan is allowed to play, weighing 300 or 400 Ibs. A man mounted 

 on a scaffold, swings a block, which raises the trepan 2 feet high, and lets it fall 

 by its own weight. The trepan is secured to the swing-lever by a cord made of reeds, 

 to which is attached a triangle of wood ; a man sits close to the cord, and at each 

 rise of the swing seizes the triangle and gives it a half turn, so that the trepan may 

 take in falling another direction. A change of workmen goes on day and night, and 

 with this continuous labour they are sometimes three years in boring wells to the re- 

 quisite depth.' 



Hand boring. The surface arrangements usually required for boring by hand, are 

 shown l>yfig. 175. In ordinary practice, a well is first sunk of such a depth that the 

 boring apparatus can be fixed in it ; and thus a stage, raised from the surface of the 

 ground, is dispensed with. A stout plank floor, well braced together by planks nailed 

 transversely, and resting on putlocks, forms the stage. In the centre of the floor is 

 a square hole, through which the boring rods pass. The plant required consists of a 

 spring pole A, to assist in giving the necessary motion to the rods when at work, the 

 three legs with pulley blocks, chain, and roller, or windlass for drawing and lowering 

 the rods, and the several lengths of rods required, with the various chisels, pumps, 

 &c. 



The borehole is usually commenced by digging a small pit about 6 feet deep, and 

 over this is set up the three legs, with pulley, &c. A few feet of iron tubing are also 

 sometimes inserted at the commencement, to protect the sides of the borehole. 



The boring rods are usually from 10 to 20 feet long. The chisel is first inserted, 

 then rods added as the work progresses. At the top of tho rods are attached two 

 handles about 4' 0" long, placed at right angles to each other. By means of these 

 the borers work the rods up and down, at the same time giving them a circular motion 

 in order to alter tho position of the chisel at each stroke. 



As the depth increases, the men at the handles or cross-bar are assisted by means 



