We had another day's delightful ramble over the hills and across the valleys of this lonely island; and except that Robinson Crusoe must have found it somewhat dull, being alone for so long before Friday came to him, Jerry and I agreed that he was in no way to be pitied, and that we should like nothing better than having to spend some time there.  We did not quite settle how long.  There are a number of caves high up in the sides of the mountain, overlooking Cumberland Bay harbour, as it is called; and those barbarous fellows, the Spaniards, compel the convicts, who labour at the stone quarries, to live in them.  The challenges of the sentinels, reaching all the way down to the harbour, broke the still silence of the night, as we lay at our anchors, ready to sail with the first dawn on the following morning.  A light wind wafted us away from that romantic spot, our visit to which is among the most pleasant recollections of our voyage.  We gazed astern as if we were looking our last on the land of our birth, and did not leave the deck till its faint blue mountains had sunk beneath the horizon.  In consequence of what we had heard from the governor, we got our guns and small arms in order, to be ready for the supposed pirates, should we fall in with them, while a sharp look-out was kept, that we might not be taken unawares.  Captain Frankland was too brave and experienced a man to be afraid of taking necessary precautions on all occasions.  It did not occur to the captain, till we had been some time at sea, to inquire of Manuel Silva whether he knew anything of the pirates.  Grave suspicions had begun to cross his mind that he was in some way connected with them.  Of course Silva denied all knowledge of them.  When pressed to give some account of himself, he replied, "I am grateful for all your kindness.  If I have an opportunity I will show it.  I do not wish to tell you falsehoods, therefore do not press me on that subject."  With a favourable breeze we steered a course for the coast of Peru.