214 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



centre of the region at the north j)ole was by Parry, in lati- 

 tude 81 45', north of Spitzbergen, in July, 1827. 



The unexplored African area (which promises most inter- 

 esting results, from its variety of animal and vegetable life, 

 and its peculiarities in an ethnological point of view) reaches 

 on the west very closely to the coast, and it is only near the 

 equator that it has been driven inland, at the extremities of 

 Du Chaillu's journeys of 1865 and 1866, and by the high 

 point of the Ogowai River reached by Walker in the last- 

 mentioned year. The settled j^arts of the coast-land of Angola 

 give the boundary on the southwest. If the Livingstone 

 Congo expedition under Lieutenant Grandy be successful, it 

 will penetrate to the very heart of this unknown space; and 

 it is hoped that this, together with the German Congo expe- 

 dition, will secure important results. The preparations for 

 the latter are well advanced, and it is stated that Dr. Finsch, 

 the eminent ornithologist connected with the Bremen Mu- 

 seum, will accompany the party in the capacity of zoologist. 



Li Australia the great unknown desert region lies to the 

 west of the track explored from south to north by Stuart in 

 1861, and which now forms the line of telegraphic communi- 

 cation across that continent. The areas of these unknown 

 regions of the globe are estimated, approximately, at about 

 11,600,000 square miles. IZ A, February 15, 1873, 69. 



ENLARGEMENT OF COAST-LAND BY MARINE VEGETATION. 



The influence of gregarious marine plants in changing the 

 form and increasing the extent of coast, which is visible in 

 the islands of the Indian Ocean, is especially noticeable on 

 the east coast of Sumatra, on account of the adaptation of 

 the shore in its shape and nature to the propagation and 

 growth of Rhizophore{3e (the mangroves), as well as by reason 

 of the luxurious growth of vegetation in those regions. The 

 whole coast for miles into the interior presents an unbroken, 

 uninhabitable green flat, and the increase in depth of tlie 

 water is very gradual, as is usual on the coasts of Indian 

 islands but little above the sea-level. The gradual transition 

 from sea to land is very manifest. The earliest evidence of 

 land is the appearance, especially at high tide, of scattered 

 tips of the lower orders of marine plants, projecting above 

 the Avater like blades of grass in flooded meadow-land. These 



