koninklijke akademie van wetenschappen 
TE AMSTERDAM. 
PROCEEDINGS OF the MEETINGS 
of Saturday January 29 and February 26, 1910. 
(Translated front: Versing ^ 
Afdeeling van Zaterdag 29 Januari en 26 Februar. 1910, Dl. XV1I11._ 
COiTTEirTS. 
a x, cm x'tp u melanocr'uic _ fovaitc"from Transvaal”. (Communicated by Prof. 
H. A. Brouwer: “Pienaarite, a melanociatic loyaue 
G. A. F. Molengraaff), p. 547. (With on:: plate;. . at the tonus and 
E. Rki 
igidity”. (Communicated by Prof. C. A- Pekelharing), p. 
forces in living wood”. (Communicated by Prof. J. W.Mo 
s to the knowledge of the movement of water in plants . 
: “The thermomagnetic properties i 
JHi; “Contribution! 
ideated by Prof. J. W- Moll), p. 574. 
sunspot-spectra”, p. 584. (With 3 
H. E. J. G. dh Bois and IvOtaro H 
F. M. Jaeger: “Studies on Tellnrii 
tellurium”. (Communicated by Prof. P. 
J. J. van Laar: “Some remarks on Pi 
H. A. b— >4 ^ , Ui0 „ of * 
e frequencies of the vibrations” (1st part). (Communicated by 
H. J. E. 
exists 
Korti 
M. W. Be 
>. (W 
*ith one piaiej. 
isaccharase, an ensyme which produ 
jicated by Prof. 
Veiss and H. Kamerlingh One 
es”, p. 649. (With 2 plates). 
Geology. — “Pienaarite, a melamcratic foyaite from Transvaal. 
By H. A. Broowkr. (Communicated by Frol- »• A - ■ 
Molengraaff.) 
(Communicated in the meeting of November 27, 1909). 
Among the nepheline syenites on and to the west of the farm 
Leeuwfontein to the north-east of Pretoria, which show a complete 
series of varieties in chemical and mineralogical composU.on, the 
“collection Molkngraaff” contains a variety very nc in , 
which occurs V. mile to the west of the Pienaarsnver near the 
boundary of the farm Zeekoegat. . , 
Maeroscopically the rock shows red felpars to 1cm. up in leng* 
which have a tabular development after (010), and smaller crystal 
of red nepheline, with which contrast numerous slender pnsms of 
aegirine and bright crystals of titanite, wh.ch make up over half 
of the rock. 
Proceedings Royal Acad. Amsterdam. Vol. XII. 
