350 
Criticisms of apparatus : (1) The chief disadvantage 
of a metal (iron) condenser is the discolouration oi the 
camphor by iron rust. If the condenser were entirely ot 
copper there would be little or no colouration. 
(2> Since practically all the camphor condenses m the 
condenser tubes and only the oil and water pass into the 
receiver, a tube condenser has the disadvantage that the 
tubes would soon get blocked. Apart from this the layer 
of camphor on the tube would form a nonconducting 
medium and lessen the effeciency of the condenser. 
(3) It is difficult to clean out a tube condenser, and 
easily remove the camphor, though this could easily be done 
by a special scraper fitting the condenser tubes. 
* (4) The chief disadvantage of the particular still 
described is the time wasted in discharging and recharging. 
The discharging could be hastened by having a lateral 
opening above the perforated plate, and made air tight by 
an asbestos sheet. * . , , j 
(5) In a large still the weight of the leaves, or wood, 
especially when wet, would tend to create pressure inside, 
by blocking the passage of steam. This could be remedied 
by using a series of perforated plates, a definite quantity 
of material (wood or leaves) resting on each. 
A better plan and one which would simplify discharg- 
ing and charging would perhaps be a metal cage which could 
be lifted bodily out of the still by means of a crane or other 
mechanical device and easily emptied by inversion and re- 
placed when discharged. This would also allow steam to 
enter the material from all sides. 
Yields. 
In the first experiment with this apparatus, a whole 
tree, including roots, was received from the Batu Tiga 
Experimental Plantations and consisted of 
Leaves weighing 12| lbs. = 7*5 per cent. 
Twigs less than \ inch diameter weighing 30 lbs. = 18*2 
per cent. 
Twigs and wood over | inch diameter 93 lbs. = 56*3 per 
cent. 
Roots 29*5 lbs. = 18*0. 
Separate distillations were made of the leaves, twigs 
under \ inch diameter, wood, and root with the following 
results. 
12} lbs. of leaves yielded 2 ozs. of camphor and oil 
= 1*0 per cent. 
W 
