EXPEDITION OF THE CHALLENGER. 27 



In 1850 Captain Penny collected in Assistance Bay, in Kingston 

 Bay, and in Melville Bay, which lie between 73 45' and 74 40' north, 

 specimens of the residuum left by melted surface-ice, and of the sea- 

 bottom in these localities. Dr. Dickie, of Aberdeen, sent these ma- 

 terials to Ehrenberg, wlio made out ' tliat the residuum of the melted 

 ice consisted for the most part of the silicious cases of diatomaceous 

 plants, and of the silicious spicula of sponges; while, mixed with 

 these, were a certain nvimber of the equally silicious skeletons of those 

 low animal organisms, which were termed Polycistincce of Ehrenberg, 

 but are now known as Radiolaria. 



In 1856 a very remarkable addition to our knowledge of the nature 

 of the sea-bottom in high northern latitudes was made by Prof. Bailey 

 of West Point. Lieutenant Brooke, of the United States Navy, who 

 was employed in surveying the Sea of Kamtchatka, had succeeded in 

 obtaining specimens of the sea-bottom from greater depths than any 

 hitherto reached, namely, from 2,700 fathoms (16,200 feet) in 66 46' 

 north, and 168 18' east; and from 1,700 fathoms (10,200 feet) in 60 

 15' north, and 170 53' east. On examining these microscopically, 

 Prof. Bailey found, as Ehrenberg had done in the case of mud ob- 

 tained on the opposite side of the arctic region, that the fine mud 

 was made up of shells of Diatomacem, of spicula of sponges, and of 

 Itadiolaria^ with a small admixture of mineral matters, but without a 

 trace of any calcareous organisms. 



Still more complete information has been obtained concerning the 

 nature of the sea-bottom in the cold zone around the south pole. Be- 

 tween the years 1839 and 1843, Sir James Clark Ross executed his 

 famous antarctic expedition, in the course of which he penetrated, at 

 two widely-distant points of the antarctic zone, into the high lati- 

 tudes of the shores of Victoria Land and of Graham's Land, and 

 reached the parallel of 80 south. Sir James Eoss was himself a nat- 

 ui-alist of no mean acquirements, and Dr. Hooker, the present Presi- 

 dent of the Royal Society, accompanied him as naturalist to the ex- 

 pedition, so that the observations upon the fauna and flora of the 

 antarctic regions made during this cruise were sure to have a pecul- 

 iar value and importance, even had not the attention of the voyagers 

 been particularly directed to the importance of noting the occurrence 

 of the minutest forms of animal and vegetable life in the ocean. 



Among the scientific instructions for the voyage drawn up by a 

 committee of the Royal Society, however, there is a remarkable letter 

 from Von Humboldt to Lord Minto, then First Lord of the Admiralty, 

 in which, among other things, he dwells upon the significance of the 

 researches into the microscopic composition of rocks, and the discov- 

 ery of the great share which microscopic organisms take in the forma- 

 tion of the crust of the earth at the pj-esent day, made by Ehrenberg 



^ " Ueber reue Auschauunc;en des kleinsten nordlichen Polarlebens," Monatsberichte 

 der Koniglichen Akadcniie, Berlin, 1853. 



