I look up to the atmospheric vapours, and try to fathom their depths. The sky is calm and motionless. The clouds have reached the utmost limit of the lofty vault, and there lie still bathed in the bright glare of the electric light. It is not there that we must seek for the cause of this phenomenon. Then I examine the horizon, which is unbroken and clear of all mist. There is no change in its aspect. But if this noise arises from a fall, a cataract, if all this ocean flows away headlong into a lower basin yet, if that deafening roar is produced by a mass of falling water, the current must needs accelerate, and its increasing speed will give me the measure of the peril that threatens us. I consult the current: there is none. I throw an empty bottle into the sea: it lies still.