-- + - =~ 
NoveMBER 8, 1905 | 
NATURE 39 
manurial experiments with cacao, now extending over four 
years, a most striking result is noted for the plot mulched 
with grass and leaves, from which the yield per tree is 
higher than from: the plot manured with phosphate, blood, 
and potash, and 77 per cent. higher than from the un- 
manured plot. 
A series of new African species of plants determined by 
various authorities appears as ‘‘ Diagnoses Africanz, 
XVIII.,” in No. 7 of the Kew Bulletin. A Cissus col- 
lected by Mr. Dawe in Uganda is morphologically interest- 
ing on account of its bearing so-called ‘* pearl-glands ”’ 
that are regarded as food-bodies for ants. Mr. G. Massee 
contributes descriptions of a few new fungal species from 
the Gold Coast and elsewhere, as well as an article on 
potato-leaf curl. This disease is perpetuated by mycelium 
in the tubers or by conidia in the soil; it is also noted 
that the same disease occurs on tomatoes. An article by 
Mr. W. J. Bean relative to a visit to famous Scottish 
gardens furnishes a good account of the trees, especially 
conifers, that have been successfully grown in_ this 
northern, but by no means rigorous, climate. 
We have received from the Biological Laboratories, 
Massachusetts Institute of Technology, ‘‘ A Statistical 
Study of Generic Characters of the Coccacee,’’ by C. E. A. 
Winslow and Anne F. Rogers. A number of characters, 
such as average dimensions, manner of grouping, staining 
reactions, vigour of surface growth, acid production in 
dextrose and lactose broth, formation of nitrites and 
ammonia in nitrate solution, and chromogenesis, were 
determined for 500 cultures from various habitats, and 
tables are given showing the frequency distributions for 
single characters and pairs of characters. These tables 
indicate with great clearness the extreme variability of the 
Coceacez, and the impossibility of laying down hard and 
fast boundaries for the classification of individuals. At 
the same time, the authors show that certain natural 
types are apparent when the characters of the aggregate, 
and not of the individual, are considered, e.g. the relative 
frequencies of different forms of grouping, the reaction to 
Gram stain, the yigour of growth, the rapidity of form- 
ation of nitrites or ammonia, and the most frequent colour 
of the pigment formed. On the whole, they find that the 
last-named character is of most importance, and most 
highly correlated with other characters. The work is an 
interesting application of statistical methods (of a very 
simple kind) to the difficult problem of the classification 
of the bacteria. 
Tue October number of The Central—the Central 
Technical College Old Students’ Assosociation magazine— 
includes an interesting illustrated article by Mr. Bernard 
Dunell on suction gas for marine propulsion. Mr. 
Dunell describes Messrs. Thornycroft and Co.’s efforts 
in the direction of a satisfactory gas-propelled barge, and 
also of a launch, and the results which have been obtained. 
The writer then goes on to describe some novelties in the 
construction of the engine frame and in the method of 
connecting the cylinder trunks to it, the object being to 
do away with heavy bolts, and also to make the operation 
of disconnecting the cylinder head as simple and as quick 
as possible. On the question of fuel, for engines up to 
250 horse-power anthracite or coke is used, the reason 
being that a cleaner gas is obtained more readily and with 
a simpler apparatus than is possible with bituminous coal. 
The writer states that Messrs. W. Beardmore and Co. are 
just completing two marine gas engines and producers of 
500 horse-power and 1000 horse-power respectively, and 
N@LO32,, VOL. 75 || 
in these cases ordinary bituminous coal will be used. The 
results on these large units will be awaited with interest 
both from the coal point of view and also from the 
“gas versus steam’? for marine work. Mr. E. Mann 
Langley’s contribution on electric train lighting deals with 
a subject of which in a general way very little is heard. 
Although the electric lighting of trains is now taken as 
a matter of course, so little that the 
author’s description of the present-day 
generation, 
apparatus between battery and dynamo is very welcome. 
is known about it 
methods of the 
regulation, and the switching in and out 
Other papers in the same issue, on the evolution of the 
incandescent electric lamp, by Mr. A. S. E. Akerman, 
and single-phase electric traction, by Mr. L. Calisch, are 
of interest, the former especially as giving a description 
of the ‘* Linolite ’’ lamp. 
We have received from Messrs. A. Guinness, Son and 
Co., Ltd., of Dublin, a copy of part il. of vol. i. of the 
Transactions of the Guinness Research Laboratory, printed 
for private use. The principal researches carried out at 
the laboratory, of which Dr. Horace T. Brown is director, 
and published in this part, are an exhaustive investi- 
gation of the nitrogenous constituents of malt which are 
soluble in water, and a study of the water-soluble poly- 
saccharides of malt. 
A REPRINT has been received of a lecture on “ The 
Early Use of Iron,’’ delivered by Mr. Bennett Brough 
before the Iron and Steel Institute at Glasgow in March, 
and published in No. 1 of the journal of the institute 
(pp. 233-253). The lecturer summarises recent investi- 
gations of the earliest records to be found of the use of 
the metal. An interesting account is given of the use of 
iron in ancient Egypt, Syria, India, and Europe, and of 
primitive methods of working iron which still survive in 
India and among the negro races of Africa. 
Tur Nobel lecture for 1906, delivered by Prof. Philipp 
Lenard on May 28 before the Royal Swedish Academy of 
Sciences, has been published under the title “‘ Ueber 
Kathodenstrahlen ’’ by the firm of J. A. Barth, of Leipzig 
(pp. 44, price 1.20 marks). It contains an admirable 
historical account of the development of our knowledge 
of kkathode rays and allied phenomena, from the time of the 
early experiments of Crookes in 1879 to the present day. 
The most important stages in the investigation of the rays 
are clearly defined, and the story of the growth of the 
modern electronic theory of matter is told in a manner at 
once comprehensive and free from technicalities. The 
account given by Lenard of the genesis of his own experi- 
ments in this field is of no little historical value. A useful 
chronological review of the literature, comprising in all 
fifty-five papers, published between 1860 and 1906, is 
appended. 
As investigation of the dimorphism of calcium and 
barium carbonates has recently been described by H. E. 
Boeke in the Zeitschrift fiir anorganische Chemie (vol. CR 
pp. 244-8, August 31). It is shown that barium carbonate 
when heated in an atmosphere of CO, exhibits a sudden 
arrest of temperature at 811°. This temperature, which 
varies only by a degree or two when the rate of heating 
is altered, represents a true inversion-point for the 
dimorphous carbonate. The reverse change takes place 
less readily, but is accompanied by a marked liberation 
of heat; when cooled rapidly the arrest-point was as low 
as 761°, but slower cooling showed an arrest at 795°, 
approximating towards the temperature of the sharply- 
defined arrest-point in the heating curve. In the case of 
