SE 
SEP. 
== 
TRANSACTIONS OF THE SECTIONS. 25 
have been much greater; but as it is, it is sufficiently remarkable*. Above 100 inches 
of the rain which fell at Uttree Mullay occurred in the months when the $.W. mon- 
soon is considered to have ceased on the western or Malabar coast, and may there- 
fore be said to belong to the N.E. monsoon of the Coromandel coast, There appear 
to have been two occasions when the fall of rain was remarkable in twenty-four 
hours. On the 10th of October there fell 9 inches, and on the 26th of November 
there fell 7°35 inches; but there also fell from the 6th to the 10th of October inclu- 
sive, 29°4 inches, averaging nearly 6 inches daily, or more than falls in most of the 
counties in England in a twelvemonth. Iam glad to communicate the assurance of 
General Cullen, that not only will he continue these interesting observations throughout 
the year, but that he has also established two pluviometers in the central table land of 
Travancore, which is about thirty miles across to the Coromandel side; one at Perre- 
gaar at 2300 feet, and another on the eastern or Coromandel edge at an elevation of 
3600 feet. General Cullen considers the area of this table land to be about 2000 
square miles, much of it at an elevation of 4000 feet. He states that it is lost to 
civilization, from the Travancore government drawing only cardamoms from it, and 
rigorously prohibiting culture to protect their cardamom monopoly. ‘The main fea- 
tures of these observations correspond with those of Mahabuleshwur and Merkara, and 
testify to one of those benevolent provisions of nature which the inquirer always 
meets with, of the continuous impingement of aqueous vapour upon mountain masses, 
occasioning very great condensation, and furnishing the perennial sources of springs and 
rivers. The apparent discrepancy of the comparatively small fall of rain at Chittoor, 
situated in the midst of the great gap of Palghat, confirms this view ; for though the va- 
pour is constantly driving through the gap, it does not meet with any impediment to 
force it up into a much lower temperature than its own, and it is therefore only partially 
condensed. The paucity of rain however at Cape Comorin and Vaurioor, both open 
more or less to both monsoons, does not admit of a ready solution. If,as General Cullen 
asserts, the S.W. moonsoon beats rather from the N.W. and westerly points than from 
the 5.W., it eannot be said that Ceylon intercepts the vapour from Cape Comorin; 
and then, why is there a fall of 131 inches and 124 inches respectively at Allepy and 
Cochin on the open coast, and only 19 inches at Cape Comorin? With respect to the 
N.E. monsoon, some of its vapour may be cut off from Cape Comorin by shoulders 
or peaks from the table land of Travancore, and yet the whole mass of the table land 
does not prevent Trevandrum and Quilon from receiving a portion of the N.E. mon- 
soon, as is shown in the preceding table. A closer attention to local physical circum- 
stances is evidently necessary before a rational account can be given of these discre- 
ancies ; but General Cullen is too zealous an observer not to work out the question ; 
and I look to being enabled, at a future meeting of the Association, of laying before 
this Section a continuation of General Cullen’s observations and a satisfactory solu- 
tion of the existing difficulties. 
On a New Portable Azimuth Compass. By E. J. Dent, F.R.A.S. 
Mr. Dent exhibited this instrument. The magnetic needle was suspended in an 
inner case, and that again fitted in an outer case in such a manner as to admit of 
having either its ends reversed so as to eliminate errors of centring ; or its faces re- 
versed so as to eliminate the error of collimation. 
On the Relations of ihe Semi-Diurnal Movements of the Barometer to Land 
and Sea-Breezes. By Tuomas Horxins. 
Mr. Hopkins exhibited diagrams, drawn up from Col. Sabine’s paper ‘ On the Me- 
Pa teorology of Bombay,’ of the diurnal temperature curve, total pressure curve, and ga~ 
‘seous pressure curve; with a diagram representing the, swelling and sinking of the 
land and sea-breezes ; and endeavoured to show that these were inconsistent with the 
_ explanation given by Col. Sabine, but harmonized with alternations of pressure caused 
_ by the alternate extrication of heat and absorption of it during the alternate evapora- 
_ tions and depositions of water, in the state of clouds and dew. 
_ * Since this paper was read it has been ascertained that the fall of rain for the whole year 
was 290 inches, 
