12 



inquiry by Professor Prestwich in an interesting memoir 

 published this year. 



The power of Chalk as an absorbent and retentive agent is 

 probably the cause of the beautiful verdure of our downs in 

 spite of their exposed position and altitude. 



The Challenger expedition, which returned to England last 

 Thursday, after an absence of 3 years, under the command of 

 Captain Thomson, who succeeded Captain Nares on his appoint- 

 ment to the command of the Arctic expedition, has added to the in- 

 formation of oceanic currents, and shown thattheseabottom consists 

 of organisms whose remains have passed through more than one 

 stage. In its southern cruise no less than four distinct kinds of 

 sea-bottom were found, all apparently of purely organic matter, and 

 chiefly resembling our Lower and Upper Chalk and Upper Green- 

 Band formations. The most interesting of these is that of red- 

 clay, which, in Mr. Wyville Thompson's opinion, consists of the 

 insoluble portions of Forameniferse (Globigerina especially}, the 

 soluble portions, amounting to 98 per cent., having been removed. 

 This insoluble argillaceous matter must either have been a 

 constituent part of the shell, or deposited in its chambers after 

 death ; in the former case it is possible the carbonate of 

 lime which composed the shells might not have been entirely 

 free from iron, silica and alumina. At all events it is clear 

 depositions are now in progress very far from land, due neither 

 to denudation nor terrestrial debris. Some remarkable sound- 

 ings were taken off the north-east of New Guinea, at depths of 

 4,475 and 4,579 fathoms; the only one of the four thermometers 

 which withstood the pressure of nearly six tons on the square 

 inch recorded a bottom temperature of 34.5. A similar temper- 

 ature was found at a depth of 1,500 fathoms, it is therefore 

 clear a stratum of 3,000 fathoms in thickness occurs in these 

 seas, which has a uniform temperature of 34.5. The Expedi- 

 tion under the guidance of Mr. Mosely and other naturalists in 

 the Challenger has very recently collected and forwarded to Kew 

 seventy-nine species of ferns from Polynesia, of which eleven 

 are new. The Admiralty, Aru, and Little Kei Islands offer an 

 entirely new and untrodden ground for the study of Pteridology. 

 The total distance run by the Challenger since 2 1st December, 1872, 

 has been 68,184 miles, nearly 400 deep soundings were taken, of 

 which two were over 4,000 fathoms, nine between 3,000 and 4,000 

 fathoms, and serial temperatures were obtained at 250 stations. 



Since we last met, the Arctic Expedition has left our shores. 

 Far away now, in a region of ice and snow, our brave fellow- 

 countrymen are toiling in the vicinity of the Pole and pushing 

 forward towards the goal, which, if attained, will crown them 

 with honour and glory. The undertaking is one of deep interest 

 to the student of the natural sciences. In these unknown regions 



