THAT FAMOUS SCENE AT RIO, WHEN THE DETROIT THREATENED TO SINK TWO OF GAMA’s SHIPS. Rio de Janeiro, Feb. 8, 1894.--The first gun fired with warlike intent by an American war ship at another ship within thirty years was fired from the Detroit early on the morning of January 29 at the insurgent Brazilian ship Trajano in this harbor. A second shot was fired a few minutes later at the Guanabara, another insurgent Brazilian lying not far from the one first assaulted. Some of the facts of this incident were told in _The Sun_ on the next day after they occurred, but the whole story will be found of interest even at the date when this can be published after transmission to New York by mail. The trouble which made the firing necessary arose unexpectedly early in the last week of January. For some time before that date Admiral Gama, the insurgent leader, had been in communication with Admiral Benham with a view of enlisting the services of the American Admiral as a mediator in compromising the fight that had been wasting the substance of the nation for more than four months. So far as any one could see, Gama was sincere in saying that he desired peace and would make all honorable concessions to obtain it. Peixoto’s Government was notified of these negotiations, and in answer a promise to submit propositions for peace was obtained. But before the Government had had sufficient time for deliberation in the matter several Captains of American merchant vessels made application to Admiral Benham for protection from the fire of the insurgents while en route to the piers to discharge cargoes. The insurgents had notified the merchantmen that if they attempted to go to the piers to discharge cargo they would be fired upon. This matter was brought to the attention of Gama when, as a private citizen, he called on Benham to talk over the propositions for compromise. Gama explained his position at length. He did not wish, he said, to prevent the American ships from discharging their cargoes; he wanted only that they discharge into lighters while moored in the bay in order that he might inspect their cargoes and search for munitions of war destined for the Government. He added that this right had been conceded to him by all the foreign naval commanders theretofore--Captain Lang, the British senior officer, Captain Picking, the American senior officer before Benham’s arrival, and others, had united in prohibiting the landing of even a search-light intended for Government use, and the machine had in consequence been sent around to Santos and landed. Gama, in short, claimed the right to blockade the port of Rio on the ground that he was the Brazilian master afloat--that the Government could not function to any extent whatever on the waters of the bay.