As the flotilla approached the entrance to the lake caution increased, for it was not known how strong Fort San Carlos might prove. This fort, perhaps the only one in the country strongly built, stood at once on the shore of the lake and bank of the stream. There was one chance in a thousand that the speedy retreat of the Nicaraguans had been merely a device to lure the British into the centre of the country, where the little expedition of two hundred sailors and marines might be annihilated. In these circumstances Colonel Poison thought it well, before coming in sight of the fort, to draw up his boats along the northern bank of the San Juan River, sending out scouts to bring in necessary information regarding the stronghold. The young naval officer all through his life was noted for his energetic and reckless courage, so it was not to be wondered at that the age of twenty-two found him impatient with the delay, loth to lie inactive in his boat until the scouts returned; so he resolved upon an action that would have justly brought a court-martial upon his head had a knowledge of it come to his superior officer. He plunged alone into the tropical thicket, armed only with two pistols and a cutlass, determined to force his way through the rank vegetation along the bank of the river, and reconnoitre Fort San Carlos for himself. If he had given any thought to the matter, which it is more than likely he did not, he must have known that he ran every risk of capture and death, for the native of South America, then as now, has rarely shown any hesitation about shooting prisoners of war. Our young friend, therefore, had slight chance for his life if cut off from his comrades, and, in the circumstances, even a civilised nation would have been perfectly within its right in executing him as a spy. After leaving the lake the river San Juan bends south, and then north again. The scouts had taken the direct route to the fort across the land, but the young officer’s theory was that, if the Nicaraguans meant to fight, they would place an ambush in the dense jungle along the river, and from this place of concealment harass the flotilla before it got within gunshot of the fort. This ambuscade could easily fall back upon the fort if directly attacked and defeated. This, the young man argued was what he himself would have done had he been in command of the Nicaraguan forces, so it naturally occurred to him to discover whether the same idea had suggested itself to the commandant at San Carlos.