178 Mr. J. Brtce on the Recent Progress of the 



worked out theoretically, were a great step in this direction ; but many 

 more will be required, at vai'ious altitudes, and uuder different climates, 

 before a general law can be deduced, expressing the decrease of the quantity 

 of rain from the surface of the soil perpendicularly upwards. The views 

 which he has developed are well known to meteorologists, and have met 

 with general acceptance. An account of them will be found in the third, 

 fourth, and fifth Reports of the Bi-itish Association, also in Professor 

 Forbes's second Report to the British Association, 1840, where they 

 are spoken of with high approval. Thej' were not put forward as com- 

 plete, but merely as a partial solution of a most diiBcult problem, await- 

 ing further and extended observations for its complete solution. In this 

 state it still remains, receiving, however, occasional illustration from 

 registers kept in various places. 



(21.) While the quantity of rain is thus known to increase from 

 moderate altitudes downwards — most probably from the drop gather- 

 ing fresh vapom* upon its surface, in consequence of its having a lower 

 t-emperatui'e than the vapour through which it successively passes in 

 its descent, just as a decanter of cold water, brought into a warm room, 

 becomes covered with dew — it must be borne in mind that the absolute 

 quantity of rain which falls on high grounds is greater than that 

 received on low surfaces towards the sea level. Hills attract and cool 

 vapom-, and cause a deposition of moisture, which might otherwise be 

 borne away, or re-dissolved into steam on meeting with warmer currents. 

 Hills near the sea have a much greater quantity on their south-west than 

 on their north-east sides, and that in Asia as well as in Europe. The 

 case of Norway and Sweden has been mentioned afready. Towards the 

 mouth of the Frith of Clyde, as at Greenock and Dunoon, and among 

 the hills northward, as at Lochgoilhead and Arrochar, tlie rainfall is 

 from fifty to sixty inches ; at Glasgow and Paisley, no more than 35*27 

 inches. The lake mountains of Cumberland and Westmoreland, rising 

 abruptly from the Irish Sea, towards which three principal valleys 

 open out, have the greatest rainfall yet known in Great Britain, or 

 perhaps in Europe. The latest results of Mr. Miller's long continued 

 inquiries on this subject are given in the Philosophical Transactions for 

 1852, Part I. The wettest spot in the district is 100 yards south 

 of the top of Styehead Pass, elevated 948 feet above the sea, and 580 

 feet above Seathwaite. In 1850 the rainfall at this spot was 189 '5 

 inches. But 1848 was a wetter yeai' ; and if the ratio of increase in 

 that year was the same at this spot where a gauge had not then 

 been established as at the other stations, he reckons that the amount 

 would have been 21162 inches. At Seathwaite the amount varies 

 from 144 to 161 inches in the different years, or 50'62 inches less 



