In Peru even the arid deserts are the sources of enormous wealth; for while the desolate Chinchas pour millions into the treasury, the pampa of Tamarugal, in the Tarapaca province, contributes its nitrate of soda (_salitre_) and borate of lime to swell the riches of this favoured land. It is calculated that the nitrate of soda grounds in this district cover fifty square leagues, and, allowing one hundred pounds weight of nitrate for each square yard, this will give 63,000,000 tons, which, at the present rate of consumption, will last for 1393 years.[362] In 1860 the export of nitrate of soda from the port of Iquique amounted to 1,370,248 cwts., and a good deal of borax is also exported, though its shipment is prohibited by the Government. The extensive use of mineral substances, such as guano and nitrate of soda, as a top-dressing for corn-crops, is a discovery of modern times, and these manures were not generally appreciated in England until a period between 1824 and 1829. I believe that farmers consider guano and nitrate of soda to be about equally efficacious as a top-dressing for corn; and it is now a matter of pressing interest to the agricultural community in England to reduce their prices, which are as high as twelve and sixteen pounds a ton respectively. But, with this view, a careful search for deposits of guano in other parts of the world has only led to the discovery of those at Ichaboe, on the coast of Africa, in 1843, and of those on the Arabian Kooria Mooria islands more recently. The deposit at Ichaboe was all carried off by the end of 1845, while that on Jibleea, one of the Kooria Moorias, is still being worked; but it is very inferior to the guano of the Peruvian islands.[363] On the whole these attempts to find other deposits of guano, which would tend to bring down the price in England, have failed of success; and the Peruvians may consider themselves secure of their strange source of revenue for some twenty years to come. And a stranger means of defraying nearly the whole expenditure of the state was never before heard of. In 1859 the disbursements amounted to 20,387,756 dollars, of which sum three-fourths were raised by shovelling heaps of dirt off a desolate island on the coast!