It was not as dark under the waves as might have been expected. The light of the sun penetrates, ordinarily, to a depth of not far from forty feet, and the moon's rays on this night were very strong. It was not light enough for the boys to see objects around them, but there was a soft illumination above their heads not dissimilar to the faint haze of light which lies over a country landscape situated at no great distance from a city bright with electricity.