In 1853, Count Pourtalès, an officer of the United States Coast Survey, which has done so much for scientific hydrography, observed, that the mud forming the sea-bottom at depths of one hundred and fifty fathoms, in 31° 32' N., 79° 35' W., off the Coast of Florida, was "a mixture, in about equal proportions, of Globigerinoe and black sand, probably greensand, as it makes a green mark when crushed on paper."

Our ideas of the hydrography of this great basin have been revolutionized since Stanley, second only to Livingstone among the great African explorers, in 1877 revealed the course of the main river.

I took a very active part, and have a great deal of correspondence, on the nature of the intended examinations in Hydrography and Civil Engineering.

348. hydrography, hydrographer; Neptune, Poseidon, Thetis, Triton, Naiad, Nereid; sea nymph, Siren; trident, dolphin.

His proposition was based on giving a complete account of the animal and mineral constituents of the country, its hydrography and resources; the paper on the aboriginal tribes to be contributed by General Cass.

WITH AN APPENDIX, CONTAINING VARIOUS SUBJECTS RELATING TO HYDROGRAPHY AND NATURAL HISTORY.

Geography and hydrography obtained higher estimation, and harbour-engineering and ship-building were elevated into more important separate arts, chiefly from their applications to his use.

WITH AN APPENDIX, CONTAINING VARIOUS SUBJECTS RELATING TO HYDROGRAPHY AND NATURAL HISTORY.

Remarks upon some errors in the hydrography of the south coast of Van Diemen's Land.

Remarks upon some errors in the hydrography of the south coast of Van Diemen's Land.

From these chapters Captain Horsburgh has arranged, in his valuable work on the Hydrography etc. of the Indian Ocean, a set of sailing-directions and other nautical information** that will be found useful for the navigation of the southern and eastern coasts of this continent.

In April, 1863, he lost his companion, Thornton, sent back to Europe his brother Charles and Dr. Kirk, who were both exhausted by sickness, and November 10th, for the third time, he saw Nyassa, of which he completed the hydrography.

Not only is the world indebted to COLUMBUS for this great and brilliant discovery, but every subsequent improvement in navigation, geography and hydrography, is justly attributable to his illustrious example.

RENNELL, JAMES, geographer, born near Chudleigh, Devonshire; passed from the navy to the military service of the East India Company; became surveyor-general of Bengal; retired in 1782; author of many works on the topography of India, hydrography, &c.; the "Geographical System of Herodotus Examined and Explained" is his most noted work (1742-1830).

Of the many well-known passages between the innumerable islands of that great Archipelago, there is not one which has ever been charted with plausible accuracy; and it cannot be too strongly impressed on your mind that hydrography is better served by one accurate chart than by ten approximate sketches.