494 
NATORE 
.LMarcH 24, 1904 
being second best (8-73 pence per candle-power year). As 
the average of the six series of tests, however, this order 
is reversed, the arcs being cheapest (8-7 pence) and the 
incandescent gas second (9:85 pence). It is to be noted, 
however, that the cost of the arc lighting seems to vary 
considerably with the type of lamp and conditions of 
contract ; there are three different electricity supplies in the 
City of Westminster, and the cost of the arcs on these three 
supplies is respectively 11-5, 15-1 and 8-7 pence per candle- 
power year. The triple flat-flame burners in the Strand 
cost 47-5 pence, and, indeed, there is apparently no other 
form of lighting that can compete with the arcs or Sugg’s 
high pressure burners. 
THE report of the departmental committee on the use of 
electricity in mines which has recently been published is 
likely to be read with the greatest interest by all electrical 
and mining engineers. There can be little doubt that 
electrical machinery, which is already in considerable use 
in mining both here and abroad, is destined to play a still 
more important part in the future. The extreme flexibility 
of an installation of electric power is particularly advan- 
tageous in mining work, and numerous machines for per- 
forming the heavier mining operations have been con- 
structed. The objection on the score of danger, especially 
in mines liable to an explosive atmosphere, is not in reality 
a serious one, as proper design and supervision of the 
machinery are easily obtained. The proposed rules which 
have been drawn up at the end of the report referred to 
above, though at first reading they may seem too stringent, 
should have the effect of ensuring the safety of the miners 
and of begetting confidence in electrical working, so that 
one may hope that the report will stimulate the application 
of electricity to mining. 
Dr. C. Barus, of Brown University, Providence, R.1., 
has sent us several photomicrographs of fog particles con- 
densed on X-ray and other nuclei. Unfortunately the details 
of the photographs are too fine to be reproduced satis- 
factorily in these pages. The nuclei were produced by 
passing the X-rays for from one to ten minutes through 
saturated dust-free air in a large condensation chamber. 
The nearly cubical chamber was made of wood impregnated 
with resinous cement, lined with a double layer of wet 
cotton cloth, and provided with faces of plate glass. The 
particles were caught on a plate of microscope glass 
covered with an oil film and exposed to the subsiding fog 
for thirty seconds. The plate was then adjusted for photo- 
graphy in the ensuing thirty seconds. In one photomicro- 
graph fog particles of all sizes from about 0-o005 cm. to 
0-0020 cm. are present, indicating a similar gradation of 
nuclei. Extremely fine fog particles (0.0003 cm. to 0 0009 cm. 
in diameter) appear on another picture corresponding to the 
large green-blue-purple corona, and are due to condensation 
oa phosphorus nuclei. Dr. Barus hopes to apply this photo- 
graphic method to the study of atmospheric nucleation, and 
thus to obtain those important but small qualitative differ- 
ences of nucleation which must vanish from the corona as 
a whole. 
REFERENCE is made in the Times of March 9 to a despatch 
which has been received by the India Office in which the 
Indian Government indicates the methods by which it 
hopes to effect an improvement in the quality of exported 
Indian cotton. The most difficult question, and one for 
which no remedy has been found, is how to prevent the 
admixture of inferior grades in the packing. The other 
problem which is engaging the attention of the Government 
is concerned with the improvement of the seed so that the 
NO. 1795, VOL. 69 | 
cotton obtained may be of better quality. The acclimatisa— 
tion of foreign species has not been attended with much 
success, but the Government now hopes to attain its object 
by the improvement of some of the indigenous species either 
by selection or by hydridisation. Experiments are in 
progress at Surat, and also in Behar, in the United 
Provinces, and in the Punjab. 
Ir has generally been assumed that in the wood of trees, 
especially the heart-wood, the cell-walls are entirely lignified, 
so that the paper contributed by Prof. M. C. Potter to the 
Annals of Botany, in which he gives proof of the cellulose- 
staining qualities of the walls of some cells, even in the- 
heart-wood of trees forty and sixty years old, will lead to a 
modification of present conceptions. Another fact empha- 
sised in the paper, but which has been known since Hartig 
treated the subject in 1878, is the digesting action of certaim 
fungi by which lignin is changed into cellulose compounds, 
and, as Prof. Potter shows, the same result is obtained by 
steaming wood, the explanation being that the water ex— 
tracts from the wood the substance which gives the 
characteristic lignin reaction. 
Tue vital importance to farmers of a thorough knowledge- 
of the habits of the insects which damage their crops and 
granaries is gradually being recognised by all civilised 
nations, and Italy is now taking up the matter in real 
earnest. From that country we have received Nos. 7 and 8- 
of the second series of the Bolletino of the Royal Higher 
School-of Agriculture in Portici, the former dealing with. 
insects injurious to stored grain, and the latter with the 
scale-insects of the genus Diaspis. Both are illustrated. 
From the U.S. Department of Agriculture we have re- 
ceived two Bulletins issued by the division of entomology. 
In the one Mr. F. M. Webster treats of insects attacking 
the stems of growing cereals and the best means of destroy~ 
ing them. It appears that in the States the injuries in- 
flicted on corn-stalks by no less than eight species of 
minute flies are all laid to the charge of the Hessian fly, 
and it is the object of the paper to point out how these 
different species and their modes of attack can be dis- 
tinguished from the latter. In most instances the ravages. 
of these insects can be prevented or mitigated by very 
simple measures. The second paper, by Mr. F. H. 
Chittenden, is devoted to the insect enemies of the sugar- 
beet. Although the beet-sugar industry is still in its infancy 
in the States, about 150 species of insects are known to prey 
on beet, and although comparatively few of these inflict 
there is little doubt that, as the cultivation 
of this crop increases, other kinds will use it as a food- 
supply, so that more extensive injuries may be looked for 
every successive season. 
serious losses, 
WHATEVER difference of opinion may exist as to the 
advisability of the restricted sense in which mammalian 
generic names are now employed by a number of zoologists, 
and likewise with regard to the revival of obscure and 
frequently ‘‘ barbarous ’’ names for such genera, absolute 
unanimity must prevail among all naturalists as to the value 
and importance of a thoroughly complete and trustworthy list 
of all the generic names for mammals which have ever been 
given. Such a list has been compiled, with immense labour, 
by Mr. T. S. Palmer, and forms No. 23 of the ‘*‘ North 
American Fauna,”’ in course of publication by the Biological’ 
Division of the U.S. Department of Agriculture. When it 
is stated that up to the end of 1900 more than 4000 generic 
names for mammals had been proposed, and that more tham 
100 new ones were added in 1901, some idea of the magni-— 
tude of Mr. Palmer’s task may be gleaned, although only 
