An invitation to the Swedish court was urged upon Descartes, and after much hesitation accepted; a vessel of the royal navy was ordered to wait upon him, and in September 1649 he left Egmond for the north.
Unlike the army, which is purely colonial, the navy in Netherlands India is partly colonial, partly belonging to the royal navy of the Netherlands, and its expenses are therefore borne partly by the mother country and partly by the colony.
About six ironclads and twenty smaller vessels of the royal navy are stationed in colonial waters; the vessels of the colonial marine number about twenty-four, and undertake police supervision, prevention of slave trading, &c.
The marine hydrometers, as supplied by the British government to the royal navy and the merchant marine, are glass instruments with slender stems, and generally serve to indicate specific gravities from 1.000 to 1.040.
The town was noted for the manufacture of ropes and cables as early as 1213, and an act of parliament (21 Henry VIII.) shows that the inhabitants had "from time out of mind" made the cables, ropes and hawsers for the royal navy and for most of the other ships.