136 
interrupts or reduces the strength of the heating current when 
the required temperature has been reached. It might be thought 
that this arrangement would give rise to considerable fluctuations 
of temperature with the making and breaking of the current, 
but it is found that the makes and breaks follow each other so 
rapidly, often two, three or even more times in a second, that 
the variations cannot be detected witha differential thermometer 
which ought to be sensitive to within a two-thousandth part of 
a degree. 
IN the Revue générale des Sciences of April 30, M. Nordmann 
proposes a theory of the propagation of electric force from the 
sun into space which is based on the assumption that Hertzian 
waves are emitted from the surface of our luminary, and that 
the emission of these electric waves must be particularly intense 
at epochs of maximum solar activity. M. Nordmann admits 
that hitherto attempts to discover Hertzian waves in the solar 
radiation have led to a negative result; but, in his opinion, 
this may be explained by the copious absorption of the electric 
undulations in the higher layers of our atmosphere. On this 
hypothetical basis the theory attempts an explanation of 
cometary phenomena, of terrestrial magnetism, and of the 
luminosity of matter in the nebulz and in the vicinity of tem- 
porary stars. M. Nordmann’s paper thus covers the same 
ground as the previous researches of Prof. Arrhenius. But the 
distinguished Swedish physicist advocates the theory of cor- 
puscular electric emission, and M. Nordmann endeavours to 
show that some grave objection. may be urged against -this 
point of view, and that, on the whole, the cosmical phenomena 
here considered are better explained by the undulatory electric 
theory of Maxwell and Hertz. 
Messrs. ROSENBERG AND Co. have submitted to us for 
examination a portable Rontgen ray outfit which they have 
produced. The outfit consists of a 10-inch spark coil of special 
construction with tube, holder, fluorescope and accessories, the 
whole fitted ina strong box measuring 2 feet 1 inch x 11 inches 
x 14 inches. The coil when tested with a 12-volt accumulator 
sparked well at 103 inches—the distance between the discharging 
pillars. The break has large platinum points, and the sparking 
can be regulated with great nicety. For those who prefer an 
electrolytic break there is a means of throwing out the con- 
denser, and other breaks can be used with little alteration. 
We should advise those who wish to use this apparatus con- 
‘nuously to have a separate tube-holder, as that supplied with the 
outfit is fixed to the box, and consequently would render the 
operator liable to ‘‘ X-ray dermatitis.” The screen is thickly 
and evenly coated, and measures 7 10 inches. One advan- 
tage of this outfit is that when the box is locked everything is 
safe, as all attachments are covered up and cannot possibly be 
damaged. There is ample room inside for plates, volt- and 
am-meters, and the box contains all that is required except the 
accumulator. As being trustworthy, cheap and handy, the 
outfit can be recommended for the purpose for which it is 
intended, and those who have not made a special study of 
X-ray work will find little difficulty in obtaining good results 
with it. 
A DISCUSSION of the rainfall of Saxony ard the Thuringian 
provinces, with coloured map, by Dr. G. Hellmann, has been 
published on the same plan as that adopted for several of the 
other German States which have preceded it. The work is 
based upon the results of ten years’ observations, and forms a 
valuable contribution to the rainfall statistics of that part of 
Europe. The mean annual rainfall for the whole area is rather 
more than 23 inches, but in the neighbourhood of the Hartz 
Mountains to the west and the Thuringian forests to the south, 
the annual fall exceeds double that amount; in the central 
NO. 1701, VOL. 66] 
NATURE 
[JUNE 5, 1902 
parts of the province of Saxony the rainfall does not exceed 20° 
inches. The discussion gives full details of the monthly values. 
and of the greatest fall in various short intervals of time. 
THE Royal Meteorological Society has published a fifth 
edition of ‘‘ Hints to Meteorological Observers,” by Mr. W. 
Marriott. This useful little work, consisting of only sixty pages, 
of which twenty pages are tables of reduction, contains all that 
is necessary for the purpose for which it is intended, and, what 
we think is of much importance, nothing that is not necessary. 
Among the chief additions to this new issue are instructions for 
the construction of thermometer screens for tropical countries, a 
description of Mr. Dines’s pressure tube anemometers, which are 
likely to come into more general use, and pictures to accompany 
the cloud nomenclature adopted by the International Meteoro- 
logical Committee. The Meteorological Congress held at Rome 
in 1879 expressed the opinion that an international dictionary of 
meteorology should be published, and as a first step towards the 
carrying out of this resolution a ‘‘ Glossary of Meteorological 
Terms” has been added, which will be of considerable assist- 
ance, especially to younger observers. 
THE annual report issued by Mr. J. B. Carruthers, Govern- 
ment mycologist at the Royal Botanic Gardens, Ceylon, records 
important work completed or in progress. Of fungal diseases, 
those which attack the tea plant naturally receive the most 
attention. The most important of the leaf diseases, known as 
grey blight and caused by Pestalozeia Guepinz, seems to be 
confined to the tea shrub, as it has not been found on the leaves 
of plants growing in the jungle or elsewhere in the vicinity of 
diseased tea plants. Experiments are being carried on to de- 
termine how far the disease may be carried by spores, and the 
liability of weak plants to succumb to the disease. The dis- 
covery of the ascus-bearing fruit on the stem reveals a method 
by which the fungus can perpetuate itself. Under ordinary 
circumstances it is confined to the leaf, but if it can attain a 
vigorous state of development it may grow down the leaf-stalk 
into the stem and there form its fruit. A destructive root disease 
is due to Rosellinta radictiferda, a fungus which can grow both 
as a saprophyte and asa parasite. It starts on dead timber, 
such as the root-tissues of a dead Symplocos, and when the soil 
is thoroughly wet it can travel and spread to the roots of living 
plants, notably the tea plant. An effectual remedy consists in 
cutting deep drains at least a foot broad. Other subjects in- 
vestigated were cacao canker, finger and toe disease, dry rot 
and pollination of cacao flowers. 
THE Journal of the Anthropological Institute is highly credit- 
able both to the Institute and to Britain ; it is, as a matter of fact, 
the best extant journal that deals with anthropology in a com- 
prehensive manner, and it is to be regretted that it does not meet 
with the circulation that is deserved by its interest and value. 
The range of the second part of vol. xxxi. extends from Wiltshire 
palzoliths and Irish copper celts to notes on Malay metal work 
and a classification of Sarawak swords; there are papers on 
African and Papuan craniology, trephining in Melanesia, colour 
vision of the natives of Upper Egypt, early Egyptian racial 
types, an ethnographical account of the natives of Manipur and 
of the Paraguayan Chaco, the animal cults of Sarawak, and a 
memorandum on the languages of the Philippines. Several of 
these articles are fully illustrated with most excellent plates, and 
it willfbe noticed that practically the whole range ofanthropology 
is covered by original articles in the current number of the 
Journal. 
Ir has long been suspected that certain prehistoric peoples 
trephined the skull of living persons for surgical reasons, and now 
we have a definite modern instance from Melanesia, The Rev. 
J. A. Crump, in his paper on “‘ Trephining in the South Seas” 
