The proximity of land seemed often to be indicated by the odor with which the winds were laden, by the abundance of marine plants, and the presence of birds. Columbus would not alter his course, as he did not wish to abate the confidence of his men in his own belief that land was to be found by steering west. The floating vegetation now became so abundant that it retarded the passage of the vessels. The sailors became seriously alarmed. They thought themselves arrived at the limit of the world, where an element, too unstable to tread upon, too dense to sail through, admonished the rash stranger to take warning and return. They feared that the caravels would be involved beyond extrication, and that the monsters lying in wait beneath the floating herbage would make an easy meal of their defenceless crews. The trade-winds, then unknown, were another cause of anxiety; for, if they always blew to the westward, as they appeared to do, how could the ships ever return eastward to Europe? In the midst of the apprehensions excited by these causes, which nearly drove the terrified men to mutiny, a contrary wind sprang up, and the revolt was thus providentially quelled. Columbus wrote in his journal, "this opposing wind came very opportunely, for my crew was in great agitation, imagining that no wind ever blew in these regions by which they could return to Spain." But the terrors of the ignorant men soon broke out afresh. Seaweed and tropical marine plants reappeared in heavy masses, and seemed to shut in the ships among their stagnant growth. The breeze no longer formed billows upon the surface of the waters. The sailors declared that they were in those dismal quarters of the world where the winds lose their impulse and the waters their equilibrium, and that soon fierce aquatic monsters would seize hold of the keels of the ships and keep them prisoners amid the weeds. In the midst of the perplexities to which Columbus was thus exposed, the sea became suddenly agitated, though the wind did not increase. This revival of motion in the element they thought relapsed into sullen inactivity, again cheered the crew into a temporary tranquillity.[2] At sunset on the 25th, Alonzo Pinzon, rushing excitedly upon the quarterdeck of the Pinta, shouted, "Land! land! My lord, I was the first to see it!" The sailors of the Nina clambered joyfully into the tops, and Columbus fell upon his knees in thanksgiving. But the morn dissipated the illusion, and the ocean stretched forth its illimitable expanse as before. On the 1st of October, one of the lieutenants declared with anguish that they were seventeen hundred miles from the Canaries, intelligence which terribly alarmed the crew, though they had really made a much greater distance, being actually twenty-one hundred miles from Teneriffe, according to Columbus' private reckoning.