Again, in the development of a mine after it is located and proved in part, there is more unavoidable economic waste. The rock is blank and silent. It can only be explored by means of expensive drifts and drillings. In one mine at Bisbee, Arizona, a shaft was sunk which had drifts at the 600-and 900-feet levels, all without result.
To these insinuations Barbicane returned no answer; perhaps he never heard of them, so absorbed was he in the calculations for his great enterprise. When his famous communication was made to the Gun Club, the captain's wrath passed all bounds; with his intense jealousy was mingled a feeling of absolute impotence. How was he to invent anything to beat this 900-feet Columbiad?