Contents xi 



PAGE 



Suggestion of the use of the Hypsometer at sea for detect- 

 ing changes of depth in the ocean . . . . . -115 



Advantages and disadvantages of the Aneroid barometer 



Examples of Rapid Variations of Atmospheric Tempera- 

 ture, especially during Fohn 116 



The curve of the temperature of the air drawn by a re- 

 cording thermometer is serrated during the day and smooth 

 during the night . . . . . . . . 117 



Characteristics of Fohn 118 



Fohn is independent of absolute height ; it depends on 

 difference of height 119 



Well-marked Fohn at sea-level in Scotland . . .120 



Effect of Fohn in Polar regions . . . . . .122 



Puffs of air of temperature higher than that of the human 

 body are characteristic of well-developed Fohn . . .123 



Necessity of acquaintance with the Term of Cooling of 

 the thermometer when used in determining the temperature 

 of the air during Fohn . . . . . . . .124 



Table XXII. Temperature observations at equal altitudes 

 over the Morteratsch Glacier and on the mountain west of it 125 



Remarkably high temperature of the air immediately con- 

 tiguous with the ice of the glacier during Fohn . . .126 



Observations of the temperature of the air when ascending 

 Piz Languard during Fohn 128 



Note. The F6hn described in the paper is fine-weather 

 Fohn, with cloudless sky and strong sun. The Fohn occur- 

 ring with overcast sky and rain is not treated. It is this 

 Fohn particularly that wastes glaciers. 



No. 3. ON ICE AND BRINES. (From the Proceedings of the Royal 



Society of Edinburgh, 1887, Vol. xiv, p. 129.) . . .13 



This investigation was undertaken in order to determine 

 experimentally whether the salt which occurs in the ice formed 

 by freezing sea-water and other saline solutions is a part of 

 the solid ice or belongs to the liquid brine which adheres to 

 the ice. The fundamental principle on which the experiments 

 were based is that, if a saline solution, such as sea-water, is 

 partially frozen and the temperature of the mixture is observed, 

 then, if the ice so formed is pure ice, it may be removed and 

 be replaced by pure ice of independent origin, such as snow, 

 having the same temperature, and if heat is then supplied, 

 the snow will melt in the solution at the same temperature as 

 that at which the ice which was produced in the solution was 

 found to melt. This was found to be the case. As a corollary, 



