Page:Physical Geography of the Sea and its Meteorology.djvu/431

 that they have no influence on the ship, but they certainly beat very hard against the ship's sides, and jarred her all over. They are felt even when below, and will wake one out of sleep."

755. Mock vigias.—Captain Wakeman, of the "Adelaide," in January, 1856, lat. 11° 21′ N., long. 33° 33’ W., encountered "tide-rips " which broke and foamed with such violence that he took them for breakers or a shoal. They sometimes are most alarming. Approaching through the stillness of the night with a roaring noise, and in the shape of tremendous rollers combing and foaming, they seem to threaten to overwhelm vessel and crew; but, breaking over the deck, they pass by, and in a few moments the sea is as smooth and as unruffled as before. Many of the "vigias" which disfigure our charts have no other foundation than the foam of a tide-rip. Captain Arquit's log of the "Comet" gives an account of many tide-rips which he encountered also in the north-east trade-wind region of the Atlantic. Thus, November 15, 1855, lat. 7° 34’ N., long. 40° 30’ W.: "Many tide-rips, which we had a good opportunity of observing when becalmed. They came up in ridges as long as the eye could reach, from all parts of the compass, but mostly from the E. I examined the ridges very closely, but could not see any fine drift-matter of any kind, as you can on the ridges of currents in many parts of the ocean. We have had no currents unless they have been from different directions, and one counteracting the other. November 16th, lat. 6° 07' N.: Light winds and pleasant. There has been no time since noon to midnight but there have been tide-rips either in sight or hearing, mostly tending N.E. and S.W. in long narrow ridges. From 8 p.m. to 9 p.m. the ocean appeared like a boiling caldron, which we sailed through for three miles. The bubbling made a loud noise, which we heard for a long time after we had sailed through it. The ship had a very singular motion, like striking her keel on a soft muddy bottom in a short rough sea-way— the same as I have felt in the harbour of Montevideo. The motion was noticed by all on board. We have had a current of fifteen miles going west. I have often noticed tide-rips in this part of the ocean before, particularly when bound home (for I have never been where I am now, bound out, before), and have mentioned them in my abstract log, but they were different from what we had last night. The ship would come to and fall off three points without any regard to the rudder."