3^9 
in contact with Chlorides— consequently fhey could not be mixed 
with sea-water, and their disinfecting power was impaired when used 
to disinfect urine, etc. A better type of coal-tar disinfectant was 
represented by Izal or by Sanitas-Okol both of which were already 
emulsified and their power was unimpaired by any admixture of 
water or liquids containing Chlorides. Sanitas-Okol, being of a 
stronger germicidal value than Izal, it could consequently be used in 
greater dilution and was therefore cheaper. (Straits Times , 19th 
August, 1910). 
INSTRUCTIONS TO MANAGERS 
AND ASSISTANTS ON RUBBER ESTATES. 
BY C. ALMA BAKER. 
A. The first, last, and only reason for Managers, Assistants, 
and coolies being employed on the Estate is the production of latex. 
The one aim and object of all the expenditure of money and labour 
is the production of the greatest quantity of rubber of the best kind 
at the lowest possible cost. 
CULTIVATION. 
B. Whatever kind of cultivation and tree sanitation is best for 
the locality, and tends to produce the best possible trees and late^, 
will be found the cheapest in the end— be it clean weeding, growing 
selected weeds, or growing everything to be turned in at certain fixed 
periods. 
The cultivation I am strongly in favour of is changkoling every- 
thing in once every three months from time of planting. This system 
has the following advantages 
1. It prevents all surface wash from the beginning. 
2. It enables the land to retain more moisture. 
3. The land does not only retain all the plant food it 
originally had, but has in addition the humus derived 
from the vegetable matter turned in four times a 
year. Also, the turning up of the under soil renders 
readily available, through exposure to the atmosphere, 
a portion of the otherwise unavailable salts. 
4. It forces the tree, by cutting the small surface laterals, 
to root firmer and lower, and to take its nourishment 
from cooler, damper, and richer soil. 
5. It greatly helps in the eradication of Formes and white 
ants, as it clears the land of all small pieces of timber, 
at the same time opening up the soil for the air and 
sunlight to penetrate. 
