Page:Popular Science Monthly Volume 26.djvu/876

856 the great river, of which the inhabitants of the adjacent country stand in extreme terror. It was not his privilege to witness an exhibition of the phenomenon, although he much wished to do so, while the people with whom he was staying desired that he or any one else should not, but he observed some of its effects and had the scene described to him. The most impressive manifestations of the force of the wave are near the mouth of the Araguary River. An eye-witness of one of the appearances of the pororóca, at that place, one of a party of soldiers, related that "shortly after the tide had stopped running out they saw something coming toward them from the ocean in a long white line, which grew bigger and whiter as it approached. Then there was a sound like the rumbling of distant thunder, which grew louder and louder as the white line came nearer, until it seemed as if the whole ocean had risen up, and was coming charging and thundering down on them, boiling over the edge of this pile of water like an endless cataract, from four to seven metres high, that spread across the whole eastern horizon. This was the pororóca! When they saw it coming, the crew became utterly demoralized, and fell to crying and praying in the bottom of the boat, expecting that it would certainly be dashed to pieces, and they themselves be drowned. The pilot, however, had the presence of mind to heave anchor before the wall of waters struck them; and, when it did strike, they were first pitched violently forward, and then lifted, and left rolling and tossing like a cork on the foaming sea it left behind, the boat nearly filled with water. But their trouble was not yet ended; for, before they had emptied the boat, two other such seas came down on them at short intervals, tossing them in the same manner, and finally leaving them within a stone's-throw of the river-bank, when another such wave would have dashed them on the shore. They had been anchored near the middle of the stream before the waves struck them, and the stream at this place is several miles wide." The signs of the devastation wrought upon the land by this gigantic wave are very impressive. Great trees, dense tropical forests, "uprooted, torn, and swept away like chaff"—for the most powerful roots of the largest trees can not withstand its rush; the destruction of the banks for some distance inland; and the formation of new land in places, are among the signs of its ravages. The pororóca is an accompaniment of the spring tides, and is due to the resistance offered to the tidal waves by the sand-bars and narrow channels which they have to meet. Its effects are most marked in the northern channels of the mouth of the Amazon, while little is known of it in the southern channels.

Drift-Copper in Iowa.—Mr. A. R. Fulton, president, read a paper, before a recent meeting of the Des Moines Academy of Science, on the pieces of native copper that occasionally occur in the drift of Iowa. lie named several specimens that had been found in different parts of the State, varying from ten ounces to thirty pounds in weight, all identical in appearance with the native copper of the Lake Superior district. They had doubtless been brought down from there by glacial action, and this made it probable that the glacial current had some time during the Ice age flowed in a southwest direction. So, pieces of lead-ore have been found in parts of the State southwest of the lead-region around Dubuque, pointing to the same supposition.

Sowing Fertilizers.—Professor Storer, of the Bussey Institution, has made some experiments to determine the quantity of given fertilizers which a man would naturally throw from his hand in sowing an acre field. Having measured off a half-acre, he employed a careful laborer, accustomed to such work, to scatter the fertilizers over the soil, directing him to sow them as if he were sowing grain thickly. Doubling the amount actually sowed on the half-acre to adapt the proportion to the standard of a whole acre, the quantities sown were, to the acre: of nitrate of soda, 214 pounds; of muriate of potash, 173 pounds; of superphosphate of lime, 173 pounds; of blood, bone, and meat-dust fertilizer, 124 pounds. All of the substances were quite finely powdered up, except the nitrate of soda. The blood, bone, and meat-dust fertilizer weighed 60 pounds to the bushel; the superphosphate of soda, 68 pounds; the muriate of soda, 69 pounds; and the nitrate of soda, 88 pounds. The experiment was repeated with