10G SKETCH OF THE PHYSICAL GEOGRAPHY' 
of layers of sandstone and quartz in which iron ore also appears. 
In the more purely granitic mountains it seems to have been observ¬ 
ed in quarts at the junction of the granite with the iron veined sand¬ 
stone strata. In the Isthmus of Kxk it has also been found at the 
junction of sandstone and granite. In Cornwall it appears to be 
dependent on granite.f 
The finest ore of Banka yields as much as 80 per cent of metal, 
the common sorts from 40 to 60. The quality of the Peninsular 
ores has not been ascertained so carefully. We are not aware that 
more than 70 per cent has ever been obtained. 
Gold Is found in the Peninsula, but, whether from inferiority of 
enterprize or natural deficiency, not in such abundance as in those 
parts of the adjacent countries of Sumatra and Borneo where it is 
systematically dug for. The present annual produce is probably a- 
bout 20,000 ounces. In all the larger specimens which we possess 
or have seen it is disseminated in small particles, and streaks in 
quartz. Like the tin ore it has not been seen in the undisintegrated 
rock. 
Copper, silver and arsenic have been detected in Banka, but ap¬ 
parently in small quantities. 
Climate .—Before inspecting the shores of the Peninsula more 
closely, it is necessary to advert to the peculiarities in climate which 
affeet the watery agencies to which they are subject, and all the ob¬ 
servations that appear necessary on the climate may be here intro¬ 
duced together. 
The mean temperature of the Peninsula is probably about 80° at 
the level of the sea. In its general humidity it also approaches to 
uniformity, but dry and rainy weather are more distinctly separated in 
the northern countries than in the southern. The latter are not sub¬ 
ject to the occasional violent rains and prolonged droughts which vi¬ 
sit the former, and the former are not exposed to the frequent tracts 
of damp, foggy 7 , rainy weather which are experienced in the latter. 
During the N. E. monsoon, which ordinarily blows from Novem- 
-f “Granite or its modification, elvan, occurs near, or at, ah the locali¬ 
ties where tin and copper ores so abound as to be worked and produce good 
mines.” De la Beetle, 
