592 
represent the outcrop of strata is distinctly suggestive. 
A student of geology should know much more about 
the foundations of mineralogy than is here given; 
but these pages were originally drawn up as a supple- 
ment to the author’s physiographic work on ‘Earth 
Features and their Meaning.” 
Mr. H. Dewey’s well-illustrated account of the 
geology of Nortn Cornwall, in the Proceedings of the 
Geologists’ Association, vol. xxv. (1914), part iii., will 
aid many visitors to the county. The conspicuous 
plain that cuts across the structure of the country 
at 300 to 400 ft. above the sea is regarded as due to 
marine denudation occurring in Pliocene times. A 
steep bluff represents the coast-line limiting this plain. 
Mr. T. C. F. Hall adds a petrological study of the 
St. Austell granite, in which the important problem 
of kaolinisation is discussed. 
GEOLOGISTS may note in Fortschritte der Miner- 
alogie, for 1914, an elaborate review, by M. Stark, 
with a bibliography of 534 entries, on the question 
of petrographic provinces. From the work of Judd 
in 1876, who is quoted in the bibliography as ‘‘W. 
Iudd,’’? we are brought through a large number of 
regions where relationships have been claimed for ig- 
neous rocks of diverse characters. As a result of this 
survey, two main groups, already unfortunately named 
by Becke Atlantic and Pacific, are held to be well 
established, and we are led to understand that an 
original magma combining these materials no longer 
exists as an important feature of the crust. The 
author concludes that the Pacific type dominated in 
early geological ages, while the Atlantic type has been 
brought almost to an equality with the Pacific since 
Eocene times, and will ultimately prevail completely 
over it. 
Tue Geological Survey of New Jersey, under the 
care of Dr. H. B. Kiimmel, has issued a ‘‘ Geologic 
Map” of the State on the scale of 1: 250,000. The 
general strike of the beds, whether Palzozoic or 
Mesozoic, is north-east and south-west, and influences 
one great feature of the country, the course of the 
Delaware River, which forms the frontier for fifty 
miles along the foot of Cretaceous escarpments. The 
Hudson on the east similarly works down along the 
strike under the famous Triassic dolerite ‘‘ palisades.”’ 
The choice of colours gives a highly artistic character 
to the map. 
Ir is frequently observed that in certain conditions 
of the atmosphere unusual visibility of distant objects 
exists. In Symons’s Meteorological Magazine for 
December last, Mr. S. Miller referred to the pheno- 
menon and asked what are the physical conditions 
that produce it, and whether it is admitted to be a 
prognostic of rain. An interesting discussion followed, 
in which several well-known men of science have 
taken part. Opinions as to the prognostic are about 
equally divided. Mr. W. H. Dines (Mag. for June) 
thinks visibility is more prevalent in rainy weather, 
but after, just as much as before, rain. Also, that 
haziness is dependent on the character of the district 
from which the air comes; smoke from the London 
NO. 2336; VOUsg:y 
NATURE 
| established in Nyanza Province. 
[AuGcuST 6, 1914 
or Clyde districts can be traced for a hundred miles. 
Dr. John Aitken (Mag. for July) concludes, from a 
large number of observations at Falkirk (Stirling), 
that transparency is adversely affected (1) by humidity, 
and (2) by the density of the population in the direction 
from which the wind blows. There is, however, no 
doubt as to the general popularity of the rain prog- 
nostic; a former careful observer (Rev. G. T. Ryves), 
referring to the well-known rhymes sometimes ascribed 
to Dr. Jenner, and including the line: ‘‘The distant 
hills are looking nigh,’’ remarks that visibility is 
“one of the most generally accepted signs of rain.’’ 
StncE their systematic classification by Luke 
Howard in 1803 and the modifications introduced by 
international agreement in recent years, the observa- 
tion of the forms and motions of clouds has become 
one of the most important aids to successful weather 
study, and Prof. W. Davis remarks in his excellent 
‘‘Elementary Meteorology”? that ‘‘if the observer 
wishes to learn something of atmospheric processes 
tor himself, he should give at least as much time 
to cloud observations as to all other records put to- 
gether.”. We therefore welcome an_ interesting 
address to the Occidental College on the clouds of 
California by Dr, F. A. Carpenter, local forecaster of © 
the U.S. Weather Bureau. Although occupying only 
eighteen pages it contains much useful information 
on the composition and formation of clouds. To the 
usual nomenclature he adds a local form: el velo, 
sometimes known as ‘‘high fog,’? which occurs 
morning and evening between May and September 
along a large part of the coast. Storm clouds: are 
most frequent over the northern portion of the State, 
where cloudless days average less than 100 in a year; 
in the southern part, e.g., at San Diego, there are 
nearly 300 cloudless days. Notwithstanding the pro- 
verbial sunny skies of California, the author states 
that most of the known varieties of cioud can be 
observed there. 
THE current Bulletin of the Imperial Institute 
(vol. xii., No. 2) contains among the reports of recent 
investigations by the scientific and technical staff the 
results of the examination of soils from Nyasaland, of 
penguin guano from the Falkland Isles, and of flax 
from the East Africa Protectorate, where there is 
every prospect of the cultivation of this fibre becoming 
Other reports relate 
to cocoa from Nigeria, copals from British West 
Africa, and cohune nuts from’ British Honduras. 
Coffee cultivation in Uganda is dealt with by Mr. W. 
Small, botanist of the Department of Agriculture in 
this colony. Coffee is now the staple crop of European 
planters in Uganda. The area is being extended, and 
large increases in the exports of coffee may be shortly 
looked for. An article on the utilisation of fish and 
marine animals as sources of oil and manure discusses 
the composition and uses of fish oils, their sources and 
preparation, and describes the present position of the 
whaling industry. Fur farming in Canada and the 
tin resources of Malaya and India are dealt with in 
separate articles. Considerably more than half of the 
world’s supply of tin is now produced within the British 
