
442 
girth. Epiphytes are exceedingly abundant, especially 
Bromeliads and Orchids, the former excelling in 
numerical strength, the latter in number of species 
and variety of form. 
There are many excellent collecting grounds in the 
neighbourhood of Cinchona, such as the valley of the 
Mabess River to the north, Sir John Peak (both above 
Newhaven Gap, and below that pass, along the 
Latimer River), and various localities near Catherine’s 
Peak, as well as the slopes of that mountain itself. 
The preceding remarks may have served to give 
some idea of the merits of Cinchona from a strictly 
botanical point of view. There are many other places 
in Jamaica, such as the John Crow Mountains, Holly 
Mount, Mount Diablo, and, above all, the almost un- 
explored ‘cock-pit country,” which are undoubtedly 
rich in botanical interest. 
It may be worth while to point out that in regard 
to such considerations as personal safety and comfort, 
cost of living, and facilities for transport, Jamaica 
generally, and Cinchona in particular, compare very 
favourably indeed with other botanical stations in the 
tropics. Even in Kingston, the refreshing sea and moun- 
tain breezes, and the cool nights, render the heat quite 
supportable in the height of summer. In fact, Jamaica 
must be considered distinctly healthy, the death-rate 
for the whole island having been only 22 per tooo in 
1g12. In the mountains there is no risk of contract- 
ing any tropical disease. Anywhere in hot countries 
the nature of the water supply is a matter requiring 
the most careful consideration. Cinchona is, how- 
ever, singularly fortunate in possessing a source of 
drinking water which is above suspicion. The island 
is quite free from large carnivora and venomous 
snakes; indeed, the only noxious animals of any 
importance, apart from mosquitoes, are scorpions; 
although ticks are, in some seasons and localities, a 
source of discomfort. 
The double journey, from England to Kingston and 
back, occupies from four to six weeks, and costs 
35!. to 551. according to the route selected. Any 
botanist who is prepared to set aside a summer vaca- 
tion for the purpose can enjoy from seven to nine 
weeks in this delightful island at a total cost of 
well under rool. The agreement recently signed for 
the annual tenancy of the Cinchona Bungalow be- 
tween the Jamaican Government and a committee of 
the British Association has had the effect of making 
the house available for botanists and others. Application 
for its use may be made (with suitable credentials) 
to the chairman of the committee (Prof. F. O. Bower, 
University, Glasgow). Unfortunately, the outbreak 
of war during the first year of the tenure may prevent 
the opportunity being used. But the object of this 
article is to make the fact more fully known, and to 
show that while the scientific attractions of Cinchona 
are great, the risks are negligible. Cinchona is prob- 
ably the safest, as it is also the nearest, point to 
Great Britain where a tropical flora can be studied in 
something approaching the virgin state; and a visit 
of quite useful length can easily be fitted into an 
ordinary summer vacation. M. D. 

THE AMERICAN PHILOSOPHICAL 
SOCIETY. 
HE annual general meeting of the American 
Philosophical Society was held in Philadelphia on 
April 22-24. The meeting was opened by President 
W. W. Keen, who, with Vice-Presidents A. A. Michel- 
son, W. B. Scott, and Prof. C. L. Doolittle, presided 
over the various sessions. , 
On the evening of April 23 a reception was held in 
the hall of the Historical Society of Philadelphia, at 
which Dr. W. M. Davis, emeritus professor of 
NO. 2381, VOL. 95] 
NATURE 



[JUNE 17, 1915 

geology, Harvard University, gave an illustrated lec- 
ture on new evidence for Darwin’s theory of coral 
reefs. The lecture described the chief results of a 
Shaler Memorial voyage across the Pacific in 1914, 
with studies of the Fiji group, New Caledonia, the 
Loyalty Islands, the New Hebrides, the Great Barrier 
Reef of Australia, and the Society Islands (see 
Nature, April 15, p. 189). , 
On the afternoon of April 24 a symposium was held 
on the figure, dimensions, and constitution of the 
interior of the earth. The subject was discussed from 
the astronomical point of view by Dr. Krank 
Schlesinger, dire:tor of Allegheny Observatory, Pitts- 
burgh; from the geological point of view by Dr. T. C. 
Chamberlin, head of department of geology, Univer- 
sity of Chicago; from the seismological point of view 
by Dr. H. F. Reid, professor of dynamical geology 
and geography, Johns Hopkins University, Balti- 
more; from the geophysical point of view by Mr. J. F. 
Hayford, director of the College of Engineering, 
North-western University, Evanstown, Ill. 
Abstracts of a number of the papers read during the 
meetings have reached us from Philadelphia, and the 
following brief résumé has been compiled from them. 
In the case of most of the papers, the titles alone 
were given in the report sent to us, but we have 
omitted these as not providing information of interest. 
Prof. E. P. Adams, Princeton University: ‘The 
Hall and Corbino Effects.” 
The Hall effect is the production of a transverse 
difference of potential in a conducting sheet when an 
electric current flows through it and it is placed in a 
magnetic field perpendicular to its plane. The Cor- 
bino effect is the production of a circular current in a 
conducting disc when a radial current flows through 
it and it is placed in a magnetic field perpendicular 
to its plane. Experiments made to study the latter 
effect and to show its essential relation to the Hall 
effect are described. The symmetry of the experi- 
mental arrangement for measuring the Corbino effect, 
as well as the fact that the measurement of the Hall 
effect requires very thin sheets, gives to the Corbino 
effect an important position among galvano-magnetic 
effects. 
Dr. C. F. Brush: ‘‘Spontaneous Generation of 
Heat in Recently Hardened Steel.” . 
The author shows that the specimens of carbon tool 
steel and tungsten ‘‘ high-speed’ steel examined spon- 
taneously generated a considerable amount of heat at 
the temperature of the room after being water- 
hardened at cherry-red or white heat. The develop- 
ment of heat at steadily diminishing rate was observ- 
able for more than a month, and was accompanied 
by a shrinkage in the volume of the steel. Progress 
of heat generation and of shrinking are shown in 
curves. But that shrinking is only incident to, and is 
not the prime cause of, the generation of heat, is 
evidenced by the fact that the internal worl represented 
by the heat generated is hundreds of times greater 
than necessary to produce the observed change in 
volume. In the process of hardening, the steels in- 
creased at least 5 per cent. in volume, as shown by 
specific gravity tests of 3-in. bars and linear measure- 
ments of long thin rods. When afterwards tempered 
to light-blue colour, much shrinkage took~ place at 
once, and another large shrinkage when annealed. 
The author regards the hardened steel as being in a 
condition of great molecular strain, somewhat unstable 
at first. Spontaneous relief of a small portion of the 
strain causes the generation of heat observed until 
stability at room temperature is reached. Any con- 
siderable rise of temperature, as in tempering, permits 
a further spontaneous relief of strain, or molecular 
rearrangement, doubtless accompanied by more gene- 
ration of heat, and so on until annealing temperature 
