I do not think Dr. Schlich can possibly ever have seen a 
tropical Hevea rubber plantation worked on any commercial 
scale. In 1903 I inspected and reported on one not yet fully 
mature, but the produce from which has been valued at 6/2^. per 
pound in London during this last month (February, 1906), and I 
can, therefore, perhaps claim to speak with somewhat more of 
personal knowledge than Dr. Schlich of the matter at issue. 
The yield per acre must, of course, depend on the climate, soil, 
number of trees per acre, and skilful care in cultivation, manage- 
ment, and tapping. Such plantations should only be formed on 
high class alluvial soil in any case, but the number of trees that 
may be most advantageous per acre may vary greatly in different 
localities. Assuming the trees to stand about 18 feet apart when 
in full bearing ( i.e. each tree having a growing space of 18 x 18 = 
324 square feet) there will be 135 trees per acre. Now, experi- 
ments in Ceylon and elsewhere have shown that mature trees can 
yield upwards of 51 lbs. of dry rubber per annum: and on a basis 
of 5 lbs. this would give 135 ><5 = 675 lbs., or 6 cwt., of marketable 
rubber per acre. Diminish this by one full third, to eliminate 
risk of over-estimating — 33 1-3 per cent, seems a very ample mar- 
gin — and the yield will still be 4 cwt. per acre, or twice as much 
as Dr. Schlich says can be produced, because 10 acres for 1 ton 
equals only 2 cwt. per acre. 
As this is a matter of great importance commercially I am quite 
willing to argue it out fully with Dr. Schlich— only I must first 
know if he has ever seen any large tropical plantation of Hevea 
Braziliensis , and, if so, where and when, because this knowledge 
will be necessary both to me and to the public in such a con- 
troversy. 
(Signed) J. NISBET, 
Formerly Conservator of Forests , 
Burma. 
NICE, March 14th , 1906. 
A WARNING TO PLANTERS. 
(Thefts of Rubber Seedlings.) 
Planters would do well at the present time to keep an eye on 
their rubber-nurseries. The demand for plants and seeds especially 
for Dutch territory is so large that it has become worth while for 
Malays to raid plantations by night and convey the plants to Singa- 
pore whence they are shipped to Dutch Borneo. Upwards of a 
thousand seedling were stolen from the nurseries at the Botanic 
Gardens one night, and a planter in Malacca lost ten thousand in 
three raids. Investigations in Singapore disclosed the fact that a very 
large export of seedlings has been going on from Singapore chiefly 
to Banjermassin, at the rate of from thirteen to thirty thousand a 
