Even a prejudiced observer will readily admit that the most valuable mineral on earth is mud. Diamonds and rubies are just nowhere by comparison. I don't mean weight for weight, of course--mud is 'cheap as dirt,' to buy in small quantities--but aggregate for aggregate. Quite literally, and without hocus-pocus of any sort, the money valuation of the mud in the world must outnumber many thousand times the money valuation of all the other minerals put together. Only we reckon it usually not by the ton, but by the acre, though the acre is worth most where the mud lies deepest. Nay, more, the world's wealth is wholly based on mud. Corn, not gold, is the true standard of value. Without mud there would be no human life, no productions of any kind: for food stuffs of every description are raised on mud; and where no mud exists, or can be made to exist, there, we say, there is desert or sand-waste. Land, without mud, has no economic value. To put it briefly, the only parts of the world that count much for human habitation are the mud deposits of the great rivers, and notably of the Nile, the Euphrates, the Ganges, the Indus, the Irrawaddy, the Hoang Ho, the Yang-tse-Kiang; of the Po, the Rhone, the Danube, the Rhine, the Volga, the Dnieper; of the St. Lawrence, the Mississippi, the Missouri, the Orinoco, the Amazons, the La Plata. A corn-field is just a big mass of mud; and the deeper and purer and freer from stones or other impurities it is the better. But England, you say, is not a great river-mud field; yet it supports the densest population in the world. True; but England is an exceptional product of modern civilization. She can't feed herself: she is fed from Odessa, Alexandria, Bombay, New York, Montreal, Buenos Ayres--in other words, from the mud fields of the Russian, the Egyptian, the Indian, the American, the Canadian, the Argentine rivers. Orontes, said Juvenal, has flowed into Tiber; Nile, we may say nowadays, with equal truth, has flowed into Thames.