351 
each of a month’s duration were made, three determinations 
of the number of latex vessels and three of stem girth and bark 
thickness one meter above ground. _ The five tapping tests show 
an increase based on equal areas of 16-8 % over the old 
plantings. Based on calculations for individual trees those 
selected gave an increase of 75 %. The offspring show 
great variation in production. It seems desirable in selecting 
mother trees, that vegetative vigour should go hand in hand 
with high production. The results show that “thinning out 
trees based on the number of latex vessels does not yield satis- 
factory results ” and that a “‘ thinning out on the basis of tapping 
tests and production measurements is preferable.’ 
Experiments in tapping have already been urged as having 
an important bearing on the choice of trees to be used for selection 
(see Kew. Bull. 1920, p. 118), and the records made by Dr. De Jong 
(quoted in the “Trop. Agric.” from “ Arch. v. Rubbercultuur,”’ 
June 1921),though not advanced here as conclusive, are of interest 
as being based on the more up to date methods. Larlier phe 
of tapping (see Kew. Bull. 1898, p. 260: Add. Ses. vii., p. 
ix., p. 587), including the native Amazon method, spiral, fall 
herring- -bone &c. are becoming more or less obsolete. The 
experiments in question were carried on over a period of more 
than 7 years on the principle: of (1) “ One left cut at 1-10 metre 
high on a quarter of the circumference, tapped twice daily; 
(2) two left cuts 50 cm. apart on a quarter; two left cuts 50 cm. 
apart on a quarter; two left cuts 75 cm. apart on a third; an 
three left cuts 50 cm. apart, all tapped daily, gave almost the 
same yield. The yield figures for the first 2} years, both for 
the trees which remained healthy throughout the experiment 
and for those which later developed disease (* brown bast ’) 
show that there was no difference in the rubber producing 
ability,” and it is further stated that “these tapping systems 
which use the bark to a height of 1- 60 m. have lost fewer trees 
than the tapping Nh in which the highest cut was placed 
at only 1-10 metre 
The Journal of the Botanical Society of South Africa.—We have 
received Part vii. of the Journal It is largely concerned with 
the National Botanic Gardens at Kirstenbosch near Cape Town, 
probably the most important foundation for the advancement 
of botany established in recent times. The flora of South 
Africa is so beautiful and so distinct from any other, especially 
in regard to its bulbous plants, succulents, heaths, and pelargo- 
niums, that the progress of the new headquarters for its Beudy 
and elucidation will be watched with sympathetic interest 
the world over. 
To the Journal Mr. A. R. E. Walker, of the Geological 
Department of Cape Town University, contributes an article 
on the geology of Kirstenbosch, very interesting for the informa- 
