The specific gravity of blue ground from claim No. 132 at about 170 feet from the surface was 2.268, air being 60° Fahr., and barometric pressure 25.83 inches. A cubic foot of wet blue ground would therefore weigh 141.34 lbs. The density varies slightly in different parts of the same claim and in different localities of the same mine. The greatest depth to which the blue has been worked in the open is 420 feet, and underground by means of shafts and drives about 620 feet. The deepest trial shaft, as I have already stated, is 620 feet, and still no change is found in the character of the ground, except that it is a little denser and harder to work, and in most cases is also richer in diamonds. It is a curious fact that when a claim was first opened out and found to be rich in diamonds, it generally remained so right down, and in like manner poor claims remained poor. But bad or poor layers for a time changed this rule, so far as rich claims were concerned, for after some feet had been passed, say ten to thirty feet, a change for the better would invariably take place, so that in the long run a close estimate of what a claim would yield could be made. At the present time claims which were enormously rich at the surface, notably those now forming the Northeast company, were then and are now amongst the richest claims in the mine. I may also note that a belt existed around the mine adjoining the reef, from one-quarter to half a claim in width, which was invariably poor. Poor surface claims often became changed to rich ones owing to the vicinity of a wall of floating reef, and it was often found that after months, even years, had been spent in working down a claim unprofitably, it would suddenly alter to a payable or probably a rich one, for at a varying depth alongside the floating reef, or after the reef had been removed, I have many a time known a change for the better to take place, and the owner, who had been almost reduced to the verge of bankruptcy, to be soon set upon his legs again.