The United States government must purchase it at once for the use of the nation.

Assuredly, the great European powers would stop at nothing to be beforehand with America, and gain possession of an engine so invaluable for military and naval use.

What incalculable advantages would it give to any nation, both on land and sea! Its destructive powers could not even be estimated, until its qualities and limitations were better known.

No amount of money would be too great to pay for the secret; America could not put her millions to better use.
But to buy the machine, it was necessary to find the inventor; and there seemed the chief difficulty.

In vain was Lake Kirdall searched from end to end.