JANUARY 22, 1414] 
as synthetic agents. One of the most interesting 
general articles is that contributed by Dr. E. Halford 
Ross on recent advances in our knowledge of syphilis, 
in which an account is given of the results obtained 
in the course of the McFadden researches at the 
Lister Institute; the complete cycle of development 
of the sexual and asexual elements of the Lympho- 
cytozoon pallidum, which is held to be responsible for 
the disease, is described and illustrated. One of the 
most important results established is the occurrence 
in nature of syphilis in the rabbit and other lower 
animals. 
For some years past the British Fire Prevention 
Committee has been directing attention to the question 
of the danger of celluloid, more particularly in con- 
nection with the kinematograph film trade. A special 
report, having the title, “Celluloid Dangers with 
Some Suggestions,” has been compiled on behalf of 
the committee, and was recently laid before the Cellu- 
loid Committee of the Home Office, which has 
adopted many of its suggestions. The report is, how- 
ever, largely intended for the guidance of local autho- 
rities, with the view of showing what appears to be 
technically possible, so that the authorities may be 
assisted in their administration and guided in intro- 
ducing bylaws to minimise the dangers. The report, 
which is illustrated and supplemented with tables, is 
divided into two parts; the first deals with the dangers 
of celluloid, including films, the various uses to which 
celluloid is put, and the large number of fires in which 
it has been a feature; the second part deals with the 
methods of extinguishing celluloid fires, and suggests 
possible safeguards. The report is obtainable from the 
committee’s offices, 8 Waterloo Place, Pall Mall, S.W. 
Own several previous occasions attention has been 
directed in these columns to the Bulletin of the Cal- 
cutta Mathematical Society, not so much on account 
of the original papers published in it as because it 
contains notes, reviews, and short notices of a mis- 
cellaneous and personal character attempting to 
chronicle the main events which are passing in the 
mathematical world. We have now received vol. i., 
No. 4, January, 1913 the date of receipt at the offices 
of Nature being November 8, 1913. It possesses all 
these excellent features in a similar degree to its pre- 
decessors, but it will be found that all the ‘‘ Notes and 
News” refer to the year 1909. Information of a 
somewhat similar kind is published regularly in the 
Bulletin of the American Mathematical Society, but 
here, however, the activity and energy of American 
and German mathematicians quite throws British in- 
terests into the shade. Neither the Proceedings of 
the London Mathematical Society nor the Mathe- 
matical Gazette attempts anything of this kind, both 
being published in the interests of writers rather than 
of readers. It is surely desirable that some further 
attempt should be made to keep both the mathe- 
maticians and the non-mathematicians of Greater 
Britain posted up in the events that are taking place 
in the mathematical world. 
We have received a copy of a paper on an electrical 
measuring machine read before the Institution of 
Mechanical Engineers in April last, by Dr. P. E. 
NO. 2308, VOL. 92] 
NATURE 
593 
Shaw. The machine is intended for the accurate 
measurement of length gauges with plane or spherical 
ends, and makes use of the principle of electrical 
touch, that is, contact with the end surfaces is deter- 
mined when a telephone circuit is completed thereby. 
End gauges may be compared with line standards, 
and comparative readings can be relied on to 1/10,000 
of a millimetre. With a measuring machine of this 
high order of accuracy it is possible to show that 
some of the end gauges at present in use in engineer- 
ing practice have errors amounting to 15/10,000 of a 
millimetre. It appears that the gauges turned out by 
Johansson, of Sweden, and by some of the American 
machinists are so accurate as to demand the best 
available measuring appliances to detect their errors. 
The machine has been installed at the National 
Physical Laboratory. 
Tue December issue of the Journal of the Franklin 
Institute contains, among other articles, a paper by 
Mr. F. W. Peek, jun., dealing with the “dielectric 
circuit’ from the view-point of high-voltage engineer- 
ing. Mr. Peek devotes most space to transmission 
lines, and points out that air is the principal insula- 
tion, the line insulation being used for mechanical 
support. The dielectric circuit was not until recently 
understood, but it is now known that breakdown of 
insulation occurs when this is too much stressed, i.e. 
when the dielectric flux is too dense. Gaseous and 
liquid insulators, broadly speaking, behave in the same 
manner. It has been observed that the surface flux 
density, or the gradient at which visual corona starts 
or breakdown occurs, is higher for small conductors 
than for large ones—that is, air round small con- 
ductors has an apparently greater strength than 
around large ones. Investigation, however, has 
shown that the following explanation is probably cor- 
rect. The strength of the air is constant, and is equal 
to 30 kilovolts per cm., but energy is necessary to 
start rupture. Therefore rupture cannot start at the 
surface, but only after the surface gradient has been 
increased sufficiently to store the rupturing energy 
between the conductor surface and a distance of 
0-301 Vroom. away in air, where r is the radius of the 
conductor. The author deals with the grading of 
cables, the methods of breakdown in solid insulators, 
&c., and shows how, by the production of water 
vapour, the needle gap method of measuring voltages 
may give readings anything up to jo per cent. too 
high when voltages are being measured. ‘The use of 
spheres is recommended. 
Tue Journal of the Royal Society of Arts for De- 
cember 5, 1913, contains a paper on perfumery, read 
before the society by Mr. J. C. Umney. The con- 
tribution consists largely of an account of the natural 
odoriferous oils and the various synthetic products 
used in perfumes. It is pointed out that whilst Rim- 
mel in 1860 classified the essential oils chiefly accord- 
ing to their source—animal, floral, herbal, and so on— 
a classification based upon the main chemical con- 
stituents of the oils could now be adopted. Thus the 
geranium oils, citronella oil, and otto of rose, all 
containing the alcohol geraniol, are distinguished as 
the geraniol group; the linalol group includes lavender, 
neroli, and bergamot oils; and the eugenol group con- 
