about four o'clock
And , late that afternoon , a change came -- a change of so welcome a character that I believe I may , without exaggeration , say it saved our lives . For , about noon , when I was aroused by the man on watch to get the meridian altitude of the sun for the determination of the latitude , I observed a bank of purple-grey clouds gathering in the south-western quarter , their rounded edges as sharply denned as though they had been cut out of paper . There was no mistaking their character ; they portended a thunderstorm . And a thunderstorm we had about four o'clock that afternoon , of truly tropical violence . There was not a breath of wind with it , but it brought us a perfect deluge of rain , -- thrice - welcome and blessed rain , -- pouring from the overcharged clouds in sheets of warm water , soft and sweet as nectar . We let not a drop escape us that it was possible to save ; we saw that it was coming , and prepared for it by spreading the sails across the boat , and caught the welcome stream in the depressions that we had arranged for its reception , drinking out of the hollowed canvas until we could drink no more . Then , as the rain still continued to fall , we did a desperate deed ; we threw away every drop of our drinking water , in the hope of being able to refill our breakers with the sweet , fresh rain-water .