418 
NATURE 
[Marcu 4, 1897 
material causes a dangerous evolution of acetylene, the Home 
Secretary has caused inquiries to be made into the subject, with 
the result that an Order in Council has been made, bringing car- 
bide of calcium within the operation of the Petroleum Act. 
Accordingly, from the date on which the Order comes into 
force—viz. April 1—only holders of a licence under the Petro- 
leum Act may lawfully keep carbide of calcium. 
WE learn from the Zavcet, that the German Commission for 
the study of the plague will leave Germany for India in a few 
days. The members are Prof. Koch, Prof. Pfeiffer (of the 
Institution for Infectious Diseases), Prof. Gaffky (of Giessen), 
Dr. Disuderic and Dr. Sticker (of the Imperial Health Office). 
Prof. Koch will travel direct to Bombay on the completion of 
his investigations in South Africa, and till his arrival the leader 
of the Commission will be Prof. Gaffky, who was with Prof. 
Koch in British India during the great cholera epidemic of 1884, 
and assisted him in the researches which finally led to the dis- 
covery of the comma bacillus. 
Mr. Poutetr WEATHERLEY, who has for some years been 
travelling in Central Africa, has recently explored Lake Bang- 
weolo. We learn from the Arztish Central Africa Gazette that 
Mr. Weatherley has completed the circumnavigation of the 
lake, and has taken a number of careful sextant observations. 
His opinion is that M. Giraud’s survey of the lake is a little 
faulty. Mr. Weatherley visited the tree under which Living- 
stone’s heart is buried at Old Chitambo. He remarks :—‘‘ It is 
a thousand pities that some attempt is not made by people at 
home, who are interested in Livingstone and his work in Africa, 
to prevent the exact spot where he died from being hopelessly 
lost sight of, as it will be in a very few years. When the poor 
old Mpundu tree falls through fire and decay—it is now fast 
becoming a mere shell—after having kept guard so faithfully all 
these years—a quarter of a century now—there is nothing to 
replace it. Nothing could possibly be more appropriate than 
the simple rugged tree standing over the spot ; no monument 
coulc be more inexpressibly solemn, but, unfortunately, it 
cannot last for ever. The Mpundu must go, and with it, unless 
prompt steps are taken, goes the knowledge of the site of 
Livingstone’s last halting-place.”” 
In a paper read before the Royal Botanic Society on Satur- 
day last, Mr. William Martindale, a member of the Council, 
advocated the establishment by the Society, in their gardens, 
of an institute for the teaching of botany, which, he suggested, 
should be similar to the institutes on the continent. He 
urged that the institute would be of vast importance to colonists 
and emigrants, who now went to Germany in considerable 
numbers for instruction. He also stated that the medical and 
pharmaceutical schools would doubtless supply the institute 
with many of its students. In the discussion which followed 
the reading of the paper, Dr. Scott said it was an extra- 
ordinary anomaly that not one institution which taught botany in 
London had a botanic garden. He expressed his entire sym- 
pathy with the proposal. Prof. Oliver also spoke in favour of 
the proposed institution, which, he said, would be welcomed 
by all the botanists in London. Several other botanists ex- 
pressed their appreciation of the scheme. 
AN interesting lecture was recently delivered before the Sheffield 
Society of Engineers and Metallurgists, by Mr. Thomas Andrews, 
F.R.S. For some time Mr. Andrews has studied the various 
aspects of the loss of strength in iron and steel by reason of use. 
He has made exhaustive microscopical chemical and physical ex- 
amination of rails of known age and condition of service on main 
lines of railway,and has thus obtained much valuable information 
on the subject. In the course of his remarks, Mr. Andrews 
showed the difference between the loss of strength from mechan- 
NO. 1427, VOL. 55] 
ical abrasion and the deterioration of the ultimate crystalline 
structure of the metal under the fatigue of stress consequent on 
the presence of internal micro-flaws. He also demonstrated the 
effect of low temperature in reducing the impact resistance of 
rails, the influences of corrosion, and the manner in which 
vibratory stress induced microscopic internal growing flaws in 
rails. Allusion was made to the influence of various kinds of 
ballast on the permanent way. The lecturer compared the 
structure of old rails of long service with that of modern ones, 
and pointed to the sources of weakness, at the same time indi- 
cating the structure best calculated to yield the most durable and 
safe results. Mr. Andrews expressed a hope that the labours of 
the Royal Commission on the loss of strength in steel rails 
would result in a general improvement in the quality and trust- 
worthiness of the metal. 
WE have several times called attention to Dr. G. Fol- 
gheraiter’s interesting observations on the magnetisation of 
Etruscan vases. Hitherto there has been a slight uncertainty as 
to whether the magnetisation may not have undergone some 
modification during the many centuries that have elapsed since 
these vases were baked. In his latest contribution to the dé¢z 
det Lincez, Dr. Folgheraiter dispels any doubts on the matter 
by his observations on some vases which were pieced together 
from scattered fragments, discovered in excavations at Arezzo- 
If the magnetisation of the ¢erra-cotta had in any way altered 
since they were broken, it is clear that the different portions 
would have been differently affected, and the mended vases would 
have shown somewhat irregular magnetisation. So far from 
this being the case, they were found to be as regularly mag- 
netised as those which had been excavated entire, the opposite 
poles at the mouth and base being exactly 180° apart. The only 
remaining element of uncertainty is what was the orientation of 
the vases in the kiln; and Dr. Folgheraiter hopes that further 
excayations may lead to the discovery of potteries of the Etruscan 
epoch containing vases z# s¢éz. Should he be successful, we 
may look forward to exact determinations of the magnetic 
elements, which will greatly add to our knowledge of terrestrial 
magnetism. 
Dr. JuLtus PRECHT, of Heidelberg, has just published an 
important thesis on the kathodic rays, Rontgen rays, and other 
radiations emanating from vacuum tubes; which confirms the 
view that these rays are of a highly complex nature. Besides 
the rays capable of being deflected by a magnet according to the 
law of Biot and Savart (which the author has verified by photo- 
graphy), Rontgen’s, Goldstein’s, and Lenard’s raysare shown to 
be distinguishable by their chemical and photographic effects. 
Dr. Precht considers that a portion of the radiation from a 
discharge tube is not a wave-motion, because the absorption of 
the rays in passing through paper varies with the time of dura- 
tion of the radiation: it is suggested that this portion may be 
electric in its nature. Interference phenomena were obtained 
with direct and reflected R6ntgen rays, and from these their wave- 
length was found to range from 370 x 107° to 830x 10-* mm. ; 
and observing that transverse light-waves of this length cannot 
pass through black paper, the author seems to incline to the 
theory of longitudinal waves. By such interference experiments, 
wave-lengths were obtained nearly twice and four times as great 
as those found by Voller in observing the diffraction produced 
through a slit. 
Wy is it that a dietary consisting entirely of cereals and 
preserved meat induces the symptoms of scurvy? Dr. A. E. 
Wright, professor of pathology in the Army Medical School, 
Netley, has lately discussed the facts bearing upon this 
question, and he concludes that scurvy is really a condi- 
tion of acid-intoxication. This theory seems to be sup- 
