"If we have," said I severely, "the mistake is yours Master Jack; for, as you are very well aware, I have been entrusting the navigation of this ship to you." Which, by the way, was only true in a certain sense; for while I had given the young man to understand that, for his own benefit and advantage, I intended to make him perform the duty of master, and hold him responsible for the navigation, I had taken care to maintain a strict check upon his calculations and assure myself that he was making no mistakes. Of which fact he was of course quite aware. Wherefore his reply to my retort was simply to change the subject with some celerity. "I say, old chap," he remarked, "you look awfully cool and comfy. Been under the head pump, as usual, I suppose. Upon my word, if it were not for the possibility--not to say the extreme probability--of being snapped up by a shark, I should like to go overboard in a bowline and be towed for half an hour. And--talking of sharks--have you noticed how often we have seen the beggars following us since we have been in this ship? I suppose her timbers have become saturated, as it were, with the odour of the slaves she has carried, and so--but, hillo! what has happened to the barometer?" I glanced at the instrument, which, together with a tell-tale compass, swung from the skylight transoms, and saw that the mercury had sunk in the tube to the extent of nearly an inch since the last setting of the vernier; and, as it was our custom in the Slave Squadron at that time to set the instrument at 8 o'clock a.m. and 8 o'clock p.m., it meant that the mercury had fallen to that extent during the night! What was about to happen? I had observed nothing portentous in the aspect of the weather, while on deck, unless, indeed, the softening away of the trade- wind and the hazy condition of the atmosphere might be regarded as portents. Yet that could hardly be, for I had observed the same phenomena before, yet nothing particular had come of it. I decided to have a talk with Tasker, the gunner's mate, and get his views on the matter; he was a man of very considerable experience, having been a sailor before I was born; I therefore at once entered my cabin, and proceeded to dress; after which I returned to the deck, where Tasker was officer of the watch. I found him sitting aft on the stern grating, replacing his socks and shoes, which he had removed from his feet at four bells in order to take a leading part in the matutinal ceremony of washing decks. I had already seen him a little earlier that morning, and exchanged greetings with him; I therefore at once, and without any circumlocution, plunged into the subject by asking: "What do you think of the look of the weather, Mr Tasker; is there anything unusual about it, in your opinion?" Tasker rose to his feet and cast a prolonged glance at the sky before replying. Then he said slowly: