INTRODUCTION 
Area . — The Malay Peninsula as understood in this work com¬ 
prises the whole area of mainland south of Lat, 7 0 N. to the island of 
Singapore, and the small islands within twelve miles of it in Lat. i° 
N. Included in it are also the islands of Penang, Lankawi, 
Terutau and the Pulau Adang group on the west coast and the 
numerous small islands adjacent to the coasts both east and west. 
The whole area is approximately 52,820 square miles. 
Climate . — Lying so near the equator, the climate is hot and very 
wet. The average maximum temperature throughout the penin¬ 
sula is 90° Fahr., the average minimum (just before sunrise) is 
70° Fahr. The variation in temperature in Singapore is between 
minimum 71 0 and maximum 87°. At each rise of 1000 feet elevation 
there is roughly a decrease of 3 0 , and at 7000 feet the maximum is 
about 70°, the minimum 50°. However, as much as 93 0 has been 
recorded at a height of 6335 feet. 
Rainfall .— Taking the rainfall for nine years, the highest average 
at Thaiping was 163-53 inches per annum, the lowest average 70-22. 
In Singapore the rainfall varies from 82 inches to 123 inches in the 
year, and in the low country in the Federated Malay Straits it is 
about 90 inches. The North-East Monsoon commences about 
November, the South-East in the end of April or May. Rain falls 
on most days of the year, and in the south of the Malay Peninsula 
south of 6° N. there is no dry season, the only variation being that 
the heaviest rainfalls take place in December to the first fortnight 
of February, and in May there is often a short dry spell. 
The air in the very dense and lofty forests which cover the centre 
of the Malay Peninsula is very humid at all times, the sun hardly 
penetrating the thick foliage. 
North of Lat. 6° there is a considerable change of climate and a 
marked dry period occurs. I have seen the herbaceous plants in 
the rice-fields of Alor Sta quite dried up in February, but at present 
there have been no records kept of temperature or rainfall in this 
part of the peninsula. 
Geology . — The Geology of the Malay Peninsula is as yet very 
incompletely known, but some valuable papers on it have been 
IX 
