318 Scientific Intelligence: 



ing majority in favor of points between S. and N.E. Since the 

 air temperature over the continent cannot, even in summer, much 

 exceed the freezing-point on account of the ice covering, it seems 

 not unreasonable to suppose as an alternative that pressure con- 

 tinues to increase with latitude after the 75th parallel, and that 

 the southerly and easterly winds are the overflowing currents 

 from a permanent polar anti-cyclone. It was to be expected d 

 priori that a theory founded on the assumption of a homogene- 

 ous land or sea surface would require modification in the circum- 

 stances, and the vertical height of the supposed anti-cyclone need 

 not be sufficient to interfere with upper currents ; it might in fact 

 rest as a cushion on the land surface almost independent of the 

 general circulation. 



Granting the existence of the polar anti-cyclone, it is not diffi- 

 cult to imagine that the moist warm air ascending from the low- 

 pressure zone moves southward and feeds the anti-cyclone, dis- 

 charging large quantities of moisture as snow and sleet, and also 

 in the form of crystals deposited from mist, as the temperature is 

 reduced by the ice sheet ; and since the supply of vapor is great- 

 est during the more open season in the low-pressure belt, it seems 

 likely that precipitation is greatest during summer. Such cli- 

 matic conditions are fully sufficient to account for the presence 

 of glacier ice in almost unlimited quantity, provided we assume 

 the existence of continental land, an assumption strongly sup- 

 ported by our knowledge of the Arctic regions, the negative 

 evidence of Grant's Land and the positive of Franz Joseph Land 

 being specially pertinent. 



Glaciers of the valley of Alpine type are found on the most 

 stupendous scale. Ross describes one on the east coast of Vic- 

 toria Land as filling a valley bordered by mountains 6000 to 

 10,000 feet in height, and sending a tongue far into the sea. But 

 the distinctive feature is the inland ice, known as yet only by 

 the insurmountable cliffs facing the sea. This barrier is remark- 

 able for the uniformity of height it retains for long distances. 

 From the volcanoes Erebus and Terror, Ross traced it eastward 

 for 250 miles, and gives the narrow limits of 150 to 200 feet, 

 Wilkes gives for other parts 150 feet, d'Urville 100 to 150 feet, 

 and Biscoe 100 to 120 feet; in Grahamsland, on the other hand, 

 only 12 to 14 feet is stated. Again, the barrier-ice is noted by 

 the absence of detritus, or moraine material of any kind. 



The stormy weather of the southern ocean, and the strength of 

 the tidal streams are in themselves a'lmost sufficient to prove that 

 the barrier-ice is not field-ice formed at sea, but essentially inland 

 ice, and of this further evidence may be derived from its struct- 

 ure. Wilkes, Webster, d'Urville, and in particular the Challenger 

 Expedition, give information derived from the examination of 

 icebergs, and agree in describing the ice as of a stratiform struct- 

 ure, their blue layers of hard ice alternating with thicker beds of 

 white soft ice enclosing air, the latter thicker and softer near the 

 top of the ice, and the former preponderating in the lower strata. 



