94 
Records of the Goulogicul Surrey of India. 
[vou X„ 
breadth as the cutting 1 edge. By adopting this plan of shaping, instead of allowing the 
smith to diminish the width of the tool throughout the length indicated, a smooth hole can 
he made at the same time that the chisel is advancing. For boring through stiff clays, an S 
chisel is a convenient form, as it penetrates less, if the drop be carelessly increased, than does 
the straight hit, and consequently is not so likely to stick. The auger is preferred by some. 
Respecting the question, which is the most efficient pattern of tool for a given kind of 
work, I have remarked that a good deal depends upon the predilection of the workmen, and 
that the best results are attained by adhering to the form of chisel they have been first 
accustomed to handle. For general usefulness, however, there is little doubt that the 
straight hit claims pre-eminence. For stiff clays, I would recommend the Schisel, and for 
soft clays the auger. In moderately free sandstones and shales, the S chisel will do excellent 
work, and it may he used as a substitute for the straight hit. In the ordinary grits of the 
coal-measures it fails to make the same amount of way. 
To clean the hole, a pump or sludger provided with an ordinary flap-valve, or else a 
ball-valve, was employed. It possesses an advantage over the 
Cleaning tools. wimble and other revolving tools used for clearing, iu that it may 
be lowered and raised by means of a rope, and the time occupied in connecting and discon¬ 
necting the rods is saved. The ball-valve is a very simple and convenient form of valve to 
adopt, as it does not get out of order, hut the balance of general opiuion is, I believe, in 
favor of the ordinary flap-valve. 
For most of the bore holes, only a few lengths of piping besides the guide tube were 
required. When the fear of any clay swelling arose, it was found 
Pipmg ' well to push operations on without cessation, and to work night, as 
well as day, shifts. This usually obviated the necessity for lining. The most intractable 
rock was running sandstone, and experience proved that when the difficulty of keeping a 
hole was due to this cause, it was an economy of time and labor to shift to a fresh position if 
piping were not available. 
The rate of progress varied according to the rocks to be bored through, trap being the 
most refractory and ordinary felspathic silicious sandstone the most 
easy to deal with. In a scale of tractability they stand in the 
following order—a wide difference of degree separating trap and ironstone from the rest:— 
Eate of progress. 
1. Trap. 4. Clay. 
2. Ironstone. 5. Coal. 
3. Vitreous quartzose sandstone. 6. Shale. 
7. Ordinary sandstones. 
Below will be found in tabular form the speed at which some of the holes in the Wardha 
Valley were put down, and the cost of cooly-labor divided over each foot or yard. There 
were usually three shifts of workmen in the 24 hours when the holes were being continuously 
pushed forward. Each shift consisted of twelve coolies and two mates or brace-head men as 
a rule, hut sometimes an additional couple were put on, if the hole was a troublesome one, 
making sixteen men in all. The pay of the coolies was 4 annas a day, the pay of the mates 5 
annas. An overseer on Bs. 25 to 35 a mouth looked after one and sometimes two bore holes. 
The returns that 1 quote are those furnished to me by Mr. Ness and by Mr. Smyth. 
Each has adopted a form which I publish as received. 
