Then there was a great question as to the effect which would be produced by the amount of explosive at his disposal, since terrible as might be the force of the stuff, unless it were scientifically placed and distributed it would assuredly fail to accomplish the desired end.
At last, after superhuman efforts, the mine was finished.

Our stock of concentrated explosive, about four full camel loads of it, was set in as many separate chambers, each of them just large enough to receive the charge, hollowed in the primaeval rock from which the idol had been hewn.
These chambers were about twenty feet from each other, although if there had been time to prolong the tunnel, the distance should have been at least forty in order to give the stuff a wider range of action.
According to Oliver's mathematical reckoning, they were cut in the exact centre of the base of the idol, and about thirty feet below the actual body of the crouching sphinx.

As a matter of fact this reckoning was wrong in several particulars, the charges having been set farther toward the east or head of the sphinx and higher up in the base than he supposed.

When it is remembered that he had found no opportunity of measuring the monument which practically we had only seen once from behind under conditions not favourable to accuracy in such respects, or of knowing its actual length and depth, these trifling errors were not remarkable.
What was remarkable is that his general plan of operations, founded upon a mere hypothetical estimate, should have proved as accurate as it did.
At length all was prepared, and the deadly cast-iron flasks had been packed in sand, together with dynamite cartridges, the necessary detonators, electric wires, and so forth, an anxious and indeed awful task executed entirely in that stifling atmosphere by the hands of Orme and Quick.

Then began another labour, that of the filling in of the tunnels.