#11 i\}t of |lain MtJ (JEIektion. 
By GEOEGE F. BUEDEE, M.D., F.M.S. 
I N reading a paper before this Society ten years ago, I 
attempted an explanation of an observed fact in meteorology 
which had then, and has since, given rise to much discussion and 
difference of opinion. I refer to the fact that the amount of 
rain collected in gauges varies inversely with the elevation of the 
gauge above the ground. Further reflection having led me to 
modify the views expressed in the paper referred to, I have 
thought the Society might be interested in examining the 
question as it now stands. 
But, first, it may be well to recall briefly the origin and 
history of the inquiry. 
It was as long ago as the year 1766, that Dr. Heberden, an 
eminent London physician, struck with the discrepancy between 
the indications of two rain-gauges placed in neighbouring locali- 
ties but at different heights, set up a third gauge on the roof of 
Westminster Abbey, and obtained the following results : — 
Inches of rain 
in a year. 
Eatio. 
“ Below the top of a house ” . 
S9-61 ... 
‘‘On the top of a house” ...., 
... 80 
“ On Westminster Abbey ”.... 
1210 ... 
... 541 
After this the matter seems to have attracted little notice 
for many years, but Heberden’s observations were not quite 
forgotten, and prior to the year 1819 they must have- bnen 
Phil. Trans., abridged, Vol. XII., p. 660. 
Q 
