In the Appendix (pp. 137-158) there will be found various particulars relating to both the Sullivan and the Bullock Diamond Drills, and the special Tools and Supplies required therewith, which will be found use ful by intending purchasers of such appliances. Acknowledgment is due, and is hereby tendered, to the firms who have so obligingly placed their catalogues, cuts, etc., at the Author's disposal. From the materials thus supplied, details of the different drills, as well as other data and information suitable for the work in hand, have been freely extracted. The Author has also to thank Mr. Bennett H. Brough for his courtesy in sanctioning the two full quotations from his Treatise on mine-surveying.