498 



cyclone arrives in Europe from the coast of Ireland, along the Bay of 

 Biscay through Spain to the Mediterranean, there is a Fohn in the 

 Alps. If the equatorial storms attack the coast of Ireland, the Fohn 

 commences in West Switzerland with its usual accompaniments. M. 

 Wild finally concludes that the Fohn has no direct relation with the 

 Sahara, and that it arises from the ordinary moist equatorial currents of 

 air coming from the Atlantic. 



These results came under my notice for the first time in several 

 essays contained in the "Archives des Sciences Physiques et Naturelles," 

 of Geneva, for the past and present year, 1868 and 1869; and they 

 have induced me to refer to the conclusions to which I had been pre- 

 viously led from independent study of the phenomena. In 1864, when 

 listening to Sir Charles Lyell delivering his address to the British 

 Association at Bath, I was impressed with the belief that the distin- 

 guished geologist had entirely misinterpreted the phenomenon of the 

 Fohn with reference to the extension and diminution of glaciers, and 

 in a communication to the geological section I alluded to the subject. 



Subsequently, in 1867, I had an opportunity of witnessing one of 

 the less intense currents of air which the peasants of the Obeiiand and 

 Yalais call a Fohn, and which assisted in establishing in my mind the 

 true solution of the question. 



I spent the night of the 3rd of September, 1867, at Guttanen, in 

 the Hasli-thal, a place well known to be within the district where the 

 Fohn is frequent. The night was still and warm, while the sky was 

 nearly cloudless. On the morning of the 4th, while descending the 

 valley towards Im-Grund, the wind commenced blowing with consider- 

 able force from the south- south-west ; the sky was clear, and the warmth 

 of both sun and air so great, that I screened myself with a sunshade. 

 My guide cried out, "Das Fohn," and directed me to instantly fold up 

 the umbrella, and look to my steps so as to avoid the danger of being 

 blown from the narrow pathway. The few clouds scattered over the 

 sky were not at this time in rapid motion, and it seemed manifest that 

 the violence of the wind was in part due to the shape of the valley. 

 At first the wind was dry and very hot ; but the clouds continued to 

 gather rapidly, while the air grew appreciably more damp and warm. 

 In a short time the weather presented precisely the same appearances 

 as those with which we are familiar in Ireland w r hen the wind blows 

 strongly from the south-west. Towards evening, when I arrived at 

 Interlacken, the force of the wind had greatly lessened; but the sky was 

 completely covered with clouds, and rain fell abundantly during the 

 night. 



On the 5th, when passing over the Lake of Thun, I noticed that all 

 the hills and mountains were closely enveloped in mist and rain, in the 

 same manner as the hills of Cork and Kerry during southerly winds. 

 Except at its commencement, this specimen of the Fohn appeared to be 

 quite the reverse of a dry parching wind. 



In the records of meteorological observations, printed in the "Archives 

 des Sciences," I find noted under the 4th of September, at Geneva — dew 



