1854.] observed at Barjiling in the Himalayah Mountains. 55 



Phenomena of the Third Class. 



The 29th May, 1852, was a warm, dry summer day and had been 

 highly favourable to evaporation and, though invisible to the eye, the 

 air was charged with moisture which suddenly showed itself in an 

 extraordinary manner as a huge cumulus, fifteen miles in length 

 at an elevation of 11,000 feet, which was rapidly formed by conden- 

 sation of the invisible vapour caused by a chilled stream of air 

 descending from the snowy-range distant thirty-five miles ; the 

 effects of this cold blast was first shown in the formation of a cumu- 

 lus which rapidly formed, until as above described, it extended to 

 fifteen miles in length and about 5,000 feet in thickness. This fine 

 body of vapour was driven rapidly to the South, and as it approached 

 the mountain Tonglo which rises to 10,009 feet above the sea, the 

 lower portion of the cumulus, which had hitherto been stratus or 

 nearly horizontal, began throwing down about twenty water-spout- 

 like looking tails about one thousand feet in length each ; which 

 gyrated at a rapid pace increasing in length at the same time, until 

 the whole cloud burst into heavy rain. The distance of the Tonglo 

 mountain from the spot of observation was eleven and half miles, 

 therefore the gyration of the tails must have been very rapid to 

 have enabled me to see it with the naked eye. 



The attraction of this cloud by the mountain must be referred 

 either to electric causes which caused the cloud to condense into 

 moisture ; or else that the cloud had entered a cooler atmosphere 

 near the mountain than it had been travelling in before it reached 

 the;; mountain Tonglo. Snow lies in patches in May near Tonglo 

 (I have seen it in large patches on the 12th May) which of itself 

 is enough to condense any cumulus, heavily laden with moisture. 



That there was some attraction is beyond a doubt, as the tails one 

 mile North and South of the central mass of tails descended at an 

 angle of 45° with the horizon, and all seemed striving to reach the 

 very summit of the mountain, upon which they all burst upon con- 

 tact taking place. 



The following rapid and consecutive formation and dispersion of 

 clouds I have frequently observed during the summer months, when 

 the I sun, T ( pouring down its almost perpendicular rays — Darjiling 

 stands in North Latitude 27? — into the deep valleys, causes a rapid 



