But even of this device they soon grew weary; from being irregular, the supplies of provisions from some quarters ceased altogether, and the possibilities of famine began to stare the unhappy castaways in the face. It must be remembered that they were in a very weak physical condition, and that among the so-called loyal remnant there were very few who were not invalids; and they were unable to get out into the island and forage for themselves. If the able-bodied handful were to sally forth in search of provisions, the hulks would be left defenceless and at the mercy of the natives, of whose growing hostility the Admiral had by this time discovered abundant evidence. Thus little by little the food supply diminished until there was practically nothing left, and the miserable company of invalids were confronted with the alternative of either dying of starvation or desperately attempting a canoe voyage. It was from this critical situation that the spirit and resource of Columbus once more furnished a way of escape, and in these circumstances that he invented and worked a device that has since become famous--the great Eclipse Trick. Among his small library in the cabin of the ship was the book containing the astronomical tables of Regiomontanus; and from his study of this work he was aware that an eclipse of the moon was due on a certain date near at hand. He sent his Indian interpreter to visit the neighbouring caciques, summoning them to a great conference to be held on the evening of the eclipse, as the Admiral had matters of great importance to reveal to them. They duly arrived on the evening appointed; not the caciques alone, but large numbers of the native population, well prepared for whatever might take place. Columbus then addressed them through his interpreter, informing him that he was under the protection of a God who dwelt in the skies and who rewarded all who assisted him and punished all his enemies. He made an effective use of the adventures of Mendez and Porras, pointing out that Mendez, who took his voyage by the Admiral's orders, had got away in safety, but that Porras and his followers, who had departed in disobedience and mutiny, had been prevented by the heavenly power from achieving their object. He told them that his God was angry with them for their hostility and for their neglect to supply him with provisions; and that in token of his anger he was going to send them a dreadful punishment, as a sign of which they would presently see the moon change colour and lose its light, and the earth become dark.