1515 
If from this the vapour pressure is calculated at 360°, we find 
440 mm., so far below the atmospheric pressure. 
Baker’s vapour density deterininations are carried out in boiling 
mercury (360°) both according to Victor Merrer’s method and accord- 
ing to Dumas. That the substance would have had such a small 
pressure in the first determinations is, indeed, little probable. Pro- 
fessor BAKER informed me that the Dumas-bulb entirely filled with 
water after the experiment; the absence of air proves that the vapour 
pressure was not smaller than one atmosphere. Accordingly I am 
of opinion that Baker's experiments cannot be explained by the 
current theoretical considerations either. 
So we have here two series of experiments, those of Jonson and 
those of Baker, which are both still unexplained. It is desirable in 
my opinion that the vapour tension determinations of dry ammonium 
chloride are carefully repeated. It can then appear at the same 
time whether the vapour tension lines of dry and humid NH,Cl 
coincide or intersect; the latter is in my opinion the more probable 
according to the theoretical views. 
Petrography. — “On the post-carboniferous age of granites of the 
highlands of Padang.” By Dr. H. A. Brouwer. (Commu- 
nicated by Prof. G. A. F. MOLENGRAAFF). 
(Communicated in the meeting of March 27, 1915). 
The occurrence of young granites in the East Indian Archipelago 
has first been stated by MOrENGRAAFF*) as a distinct contact-meta- 
morphism was observed by him at the contact of granites with rocks 
of the mesozoic, probably jurassic Danau formation. 
Of late, mesozoic granites have been stated by Wichmann’) to 
occur also in the Moluccas, (Taliabu, Sulg-isles). 
In Sumatra, till of late all the granites have been considered as 
precarbonie ones, but the researches of these later years by SCRIVENOR, 
Toster and Votz have proved or made probable the occurrence 
of mesozoic granites in Sumatra and in the neighbouring Malacca *). 
1) G. A. F. MonenGraarr. Geologische verkenningstochten in Centraal-Borneo 
p. 458. Leiden 1200. 
2) CG. E A. Wicuwany. On some rocks of the island of Taliabu (Sula Islands). 
Proceedings Royal Acad. of Sciences. Amsterdam. Vol. XVII (1914), p. 226. 
5) J. B. Serivexor. The Rocks of Pulau Ubin and Pulau Nanas (Singapore). 
Quart. Journ. Geolog. Soc. 66. 1900. p. 429. A. Toster. Voorloopige mededeeling 
over de Geologie van de Residentie Djambi. Jaarb. Mynw. Ned. Indié over 1910, 
18—19. W. Vorz. Oberer Jura in West-Sumatra. Centralbl, f. Min. 1913, 
op 
=~! 
or 
1 
