CHEMICAL AND PHYSICAL NOTES. 93 
turn will produce a first generation of heat; this will produce a 
further yielding, and in due course a further generation of heat, and 
the effect of this initial agency, when combined with the powerful 
effect of fusion and regelation under conditions of very slight varia- 
tion of pressure, is the extraordinary rate of motion observed in 
the glaciers of Greenland. 
It has been pointed out that the whiteness of the surface of a 
glacier is due to what may correctly be termed sun burning or sun 
weathering. The icebergs which are met with at sea have an equally 
white surface ; but where the interior is exposed, either in crevasses or 
in caves melted out by the waves, the deep blue colour of the fresh 
ice is visible. It is obvious that the whole of the surface of the 
glacier which is immersed in water at greater depth than that to 
which the sun’s rays can penetrate must have the same blue colour, 
and it is equally obvious that when an iceberg turns completely over, 
it must stand out as an intensely deep blue mountain of ice among the 
multitude of sunburnt white ones. On one of the fine days during 
the sojourn of the Challenger in Antarctic waters, a striking and mag- 
nificent example of this was observed, but the cause of the blueness 
of the strange berg was quite unsuspected. If ice were collected by 
bombardment or otherwise, from such a berg, the grain would be 
large and well developed, and the ice would be quite compact and 
free from vesicles. In the region visited by Dr. Argtowski, the 
glaciers and the icebergs were comparatively small and of an Arctic 
character. The distribution of snow, névé, and ice he describes as 
being similar to that in the Alps at a height of 3000 to 4000 metres. 
There appeared to be very little melting, yet the glaciers advanced 
steadily towards the sea. In the Challenger the writer observed at 
least one large tabular berg, which was melting freely on the top, 
and streams were cascading down the sides. In Spitzbergen the 
glacier streams often take large proportions ; it will be interesting 
to know if in equally high Southern latitudes there is similar melting 
under the influence of the long polar day. 
THE DETERMINATION OF THE TEMPERATURE OF SATURATED STEAM, 
AND THE PRODUCTION OF HIGHER FIXED TEMPERATURES BY 
THE CONDENSATION OF STEAM ON SALTS AND IN SALINE | 
SoLuTIons. * 
The method of determining the pressure of the atmosphere by 
the temperature of saturated steam has for some time ceased to be 
* Chiefly a reprint of an article with the above title in the Scottish Meteorological 
Journal. 
