But it was not to gold alone that _Brazil_ was to owe the sudden increase of its prosperity which occurred during the early part of the eighteenth century. A rumour had long been current of the existence of diamonds; and one Bernardino da Fonseca Lobo had found specimens of these precious stones in the _Serro do Frio_, which he sent home to Portugal, and which procured him the title of _Capitam Mor of Villa do Principe_ for life. Diamonds were declared to be royalties, and subject to the same duties as gold. It was difficult, however, to collect these duties in the same manner; since neither by number, weight, nor measure could any equitable plan of taking the royal fifths be devised. A capitation tax upon the slaves employed was therefore decided upon. The diamonds were to be remitted, as was gold, only in the King’s ships, one per cent. on their value being charged for freight. The result of this last discovery of the produce of _Brazil_ was such that, in the course of two years, the price of diamonds in Europe went down seventy-five per cent. The property of individuals was so seriously threatened that it was found necessary, without delay, to take measures for limiting the number of diamonds extracted. In order to arrive at this end, by which the price of diamonds was to be kept up artificially, several measures were proposed, and were referred to commercial men for their opinion. The advice of Dr. Joam Mendes was to the effect that the diamond country should be reserved for the King’s use; that it should be placed under special laws; and that the diamonds should be extracted for the King’s account slowly. After due deliberation, the Court resolved to adopt the counsel thus given, in so far as to reserve the diamond country and to limit the extraction; but not to undertake it on its own account. An officer was therefore charged to mark out the limits of the forbidden district, and so heavy a capitation was imposed as to prevent all but a few persons from searching for the precious stones. It was thought that they could only be offered for sale at a heavy price.