At the same time that the depreciation of gold and silver under any general form becomes less probable, the increasing facility of communication, and the greater mutual dependence of nations in matters of credit, renders any great local difference in the value of money more improbable. Whenever the precious metals become in excess in one country, the surplus quickly reaches its neighbour. Let a sudden scarcity of food, or any other cause, create a drain of specie, the consequently increased value of money will soon draw back that which has been exported. The cost of transport, and the premium of insurance of gold, are the limits of the variations in the rates of exchange; and the charges are being diminished every day, thanks to railroads and steam communications. Before the wonderful progress in the development of industry from the commencement of the nineteenth century, we have seen the changes occurring at different periods, in the relative production of the precious metals, without any corresponding alteration in their relative values. At the close of the fifteenth century, it is true, that America, furnishing nothing but gold, and this metal having accumulated in Spain, Queen Isabella of Castile was forced to alter the relative standard of gold and silver. After the first half of the 16th century, the production of gold having ceased to preponderate, and silver being imported in great abundance, the value of the inferior metal underwent such a depreciation, that the governments of Europe, yielding to the force of circumstances, changed its relative legal value; but with these two exceptions in the monetary laws, one purely local, and the other European, we observe the production of each metal extend and diminish alternately, without any relative alteration in value of sufficient importance to attract public attention. “From the year 1645 to the commencement of the 18th century,” says M. Michel Chevalier, “silver took the lead in a most remarkable manner. Then occurred the bright days of the mines in Potosi, and the production of silver exceeded that of gold, weight for weight, in the proportion of 60 to 1; after that, and without any diminution in the produce of silver, came the glorious time for the Brazilian gold mines. Simultaneously appeared the auriferous regions of Chico, Antioguia, and Pepayou. The commercial world received from America 1 kilogramme [5]of gold for every 30 kilogrammes of silver. Thus passed the middle of the 17th century. Then the silver mines of Mexico put forth all their splendour, and the proportion increased to 40 to 1. The Brazilian mines began to diminish, whilst those of Mexico continued to increase in production; and, at the beginning of the next century, silver exceeded gold in the proportion of 57 to 1. In 1846 the production of silver still continued to predominate, and we are now at the proportion again of about 40 to 1.”