The Amazon valley began to send coagulated gum abroad: before this occurred, objects, chiefly high boots, were sent all the way to Pará to be water-proofed with a series of layers of the fresh latex. The industry was still in existence in the 1850’s, but died a natural death when rubber manufacturing got into its stride. It did not make this movement until large quantities of crude rubber began to reach world markets, and such amounts were not shipped until the Amazon received a great addition to its labour supplies. In 1877–79 one of the terrible droughts that scourge the State of Ceará drove the populace out of the foodless region; hardy, daring, the Cearenses swarmed up the Amazon, into the reaches of the upper tributaries, into the Acre, searched the forests for _seringueiras_, and gathered a great harvest of latex. A little later the bicycle was invented and popularized, rubber tyres were called for in addition to the established demand from the boot and shoe trade, and rubber export became one of the big businesses of the industrial world. The Amazon had shipped 31 tons in 1827; 156 tons in 1830; 388 tons in 1840. In another ten years she was shipping 1,467 tons; in 1860, 2,673 tons; 1870, 6,591 tons; 1880, 8,680 tons. Three years later she was sending over 11,000 tons, year by year adding about 1,000 tons until by 1890 the supply and demand came to 19,000 tons. It may be said here that up to the present demand has invariably taken the year’s supply; with great volumes coming from the Eastern plantations a surplus may occur, but with the present greatly stimulated demand such a condition is not yet in sight. Steady rises in Amazonian production went on at the end of the century, and 1903 registered the receipt of over thirty thousand tons; when in 1906–07 the crop attained thirty-eight thousand tons output it had about reached its maximum with the quantity of labour available upon the Amazon. Production has fluctuated about this figure for the last ten years. It could be increased, if the estimate of 300,000,000 untapped trees in the deep interior forests is anywhere near the mark, to almost any amount; but the present production is the work of some one hundred and twenty thousand _seringueiros_, chiefly Brazilians, with some Bolivians and Peruvians, and there is no immediate prospect of labour supplies being largely augmented.