JANUARY 7, 1904] 
NATURE 220 
The greatest difference between the value of M 
determined by observation on any one tube and the 
mean is 15-5 parts in one million, while the greatest 
change that has taken place in the value of any one 
of the manganin standards of the first division relative 
to the tubes is 45 parts in one million. 
Dr. Scheel has an interesting paper on the expansion 
of solids, describing a series of experiments using the 
Pulfrich form of the Fizeau dilatometer. The method 
leads to results of great accuracy for expansions at 
temperatures up to that of the boiling point of water; | 
abundant 
it is interesting to note that for Berlin porcelain, the 
expansion of which is of importance in connection with 
its use in the air thermometer, the author confirms the 
result of Chappuis and WHarker. Holborn and 
Gruneisen had found that at high temperatures, say 
600° C., the expansion is much less than would be 
inferred from a formula extending over a range from 
o° C. to roo? C. In this respect the porcelain re- 
sembles fused quartz. 
In another paper Lummer and Gehrcke discuss in 
a very complete manner the optical properties of dis- 
persion apparatus of high resolving power, while 
reference must be made to two papers, on the scattering 
of particles from heated metallic surfaces, especially 
those of the platinum group, and on the scattering of 
particles from kathode surfaces in a vacuum. 
It is clear from this brief notice that the range 
covered is a wide one, and that the Reichsanstalt is 
still continuing to advance our knowledge in a notable 
degree. 
RECENT GEOLOGICAL OBSERVATIONS IN 
CAPE COLONY. 
HEN Dr. Edward Brown, in 1669, carried the 
fame of the Royal Society across Europe, and 
quietly pursued his antiquarian inquiries, he remarked 
that there were ‘“‘ Wars at that time when I was in 
this Country, between the Elector Palatine and the 
Duke of Lorrain.” In a similar spirit, the geologists 
of the Cape Commission have continued their con- 
scientious work in a land divided and subdivided 
against itself, merely transferring their activity to the 
Transkeian Territories, when geological observation 
became incompatible ‘‘ with the necessities of Martial 
Law ” (igor report, p. 4). The course of a struggle 
which at one time threatened the Empire is referred 
to as *‘ the military problem ’’; the serene permanence 
of scientific work has seldom been more aptly illus- 
trated. : 
The region to which the assistant geologists were 
temporarily exiled lay on the south-east coast of Cape 
Colony, between the Great Kei River and the frontier 
of Natal, in native territories where military rule was 
not proclaimed. In the spring of 1901, however, 
observations had been rendered possible nearer head- 
quarters, in the divisions of Swellendam and Rivers- 
dale. These led to some corrections of the map issued 
in 1897. | Messrs. Rogers and Schwarz point out how 
the possibly Cretaceous Uitenhage series can often be 
distinguished from the overlying gravels only by the 
occurrence of fragments of a quartzite in the latter. 
This quartzite is a well marked rock that caps the 
Uitenhage series uncontformably. 
The same authors, who then formed the field-staff 
of the survey, describe the general features of the lands 
examined beyond the Skei. Unlike the western 
portion of the Colony, there are here no folded moun- 
1 Cape of Good Hope. Department of Agriculture. Annual Reports of 
the Geological Commission for 1 d E TH 
Liss gor and 1902. (Cape Town: Cafe Time. 
Ltd., Government Printers, 1902 and 1903 eae a ce 
NO. 1784, VOL. 69] 
tains near the coast, and the moisture-laden air from 
the sea penetrates in consequence far inland. The 
rivers come down from the Storm Bergen and 
Drakensberg ranges, and cut steep valleys through 
the vast steps formed by successively elevated ‘‘ coastal 
plains.’’ From the coast inwards, we may move 
along the edge of the same stratum, on the line of 
strike of a great synclinal. Starting from its axis, 
about the mouth of the Kei River, older and older 
beds are met with as we go north-east. In Kentani, 
the first division, the igneous intrusive masses are so 
as to obscure the stratified deposits of 
Karroo age, and seem (p. 31) to have eaten up the 
latter in making a place for themselves in the crust. 
The variations from dolerite to granite appear to have 
originated in a single magma. On nearing Pondo- 
land, the Dwyka Conglomerate, of Lower Karroo age, 
and always important as a lithological horizon, occurs 
with its characteristic glaciated boulders. The Table 
Mountain Sandstone of the Cape system comes out 
| uncrumpled from beneath it. 
The most interesting 
work done in Pondoland was the more detailed ex- 
| amination of the Cretaceous beds, already brought to 
notice by Baily and Garden in 1855, and by Griesbach 
in 1871. The lower layers contain rolled chelonian 
bones, and were deposited in shallow water. Among 
the ‘‘ superficial,’ or post-Cretaceous, beds of Kentani 
is (p. 66) a fossiliferous quartzite of fresh-water 
origin. 
The report for 1902 sees Mr. Rogers installed as 
acting or chief geologist in place of Dr. Corstorphine, 
who has been tempted northwards. Mr. A. L. du 
Toit, himself a colonial, as we are happy to observe, 
joins the staff as an assistant. The main work for 
tg02 lay in Matatiele, up against the Drakensberg 
Range, and still in native territories. The intimate 
connection of volcanic energy with the range is shown 
by the discovery of a chain of nineteen vents, in addi- 
tion to five recorded to the south-west by Mr. Dunn 
as far back as 1878. They are filled with dolerite or 
agglomerate, the latter consisting largely of blown-up 
sedimentary material. The lavas that flowed from 
them, in Jurassic times, over the upper beds of the 
Karroo system, have been weathered away on the 
south-east, but are preserved upon the north-west 
slope. Mr. Schwarz points out (report for 1902, pp. 51 
and 60) how the trend of the volcanic line is related to 
persistent north-east and south-west axes of folding, 
which have determined in the past the coast-line of 
this part of Africa. The old eastern continent had 
receded, by Jurassic times, as far as the line of volcanic 
vents; a later uplift must have been followed by sub- 
sidence, whereby the present Transkeian coast-line was 
determined. The edge of the Drakensberg plateau 
may thus be regarded as the crest of a uniclinal fold, 
the native territories lying on the lower limb. | 
The strata encountered range down from the “* Cave 
Sandstone,”? which may be partly of explosive origin, 
to permo-Carboniferous beds. All these are included 
in the convenient but too comprehensive Karroo 
system (p. 103), though the upper zones may be as 
modern as the Jurassic period. Indications of reptilian 
remains are already known (p. 32). The ‘‘ Molteno 
beds,’? more recent than the famous Theriodont 
horizons of the Karroo system, contain thin coals and 
oil shales. The natives at present use ox-droppings 
for fuel, and thus deprive the poor soil of a valuable 
fertilising agent. ie 
Work was also done in the typical Karroo district, 
south of the Nieuweveld escarpment, where new dis- 
coveries of Pareiasaurus have resulted. Considerable 
pains have been taken to place the collections of the 
Commission in the hands of specialists for determin- 
