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NATORE 
[APRIL 11, 1O"2 
account, and it is found, both from theory and from 
experiment, that in certain cases the deflection may be 
from three to five times as great as that given by the 
usual EI/p formula. 
In the case of sudden explosions or volcanic erup- 
tions anomalous sound phenomena frequently occur, 
the noise of the explosion being sometimes heard at 
abnormal distances, while it is inaudible at other 
places nearer the source. These phenomena were 
discussed in 1910 by Dr. G. v. d. Borne. In the 
Proceedings of the Tokyo Mathematico-Physical 
Society, vi., 9, Mr. S. Fujiwhara gives an analytical 
investigation based on a formula for the velocity 
potential subject to the assumptions that the atmo- 
spheric density follows the adiabatic law, and that 
the wind velocity varies very slowly with the height, 
the velocity of sound thus varying with the altitude. 
In Blatt 4, torr, of the Royal Observatory of Wil- 
helmshaven, in continuation of similar previous work, 
Prof. Bidlingmaier gives a graphical representation 
of the hourly magnetic character of the last half of 
Ig1rt, based on a scale ‘‘o,” “1, of disturbance. 
As an extension, he develops a scale of magnetic 
“‘activity,’’ ultimately dependent on the range of the 
magnetic elements in each hour. If this lies between 
50(n—1)y and sony, the measure of the activity is 
n°—(n—1)°. This idea is applied to the ten years 
1890 to 1899, and conclusions are drawn as to the 
activity of the earth’s horizontal magnetic field in the 
several years. 
In his Nobel lecture to the Academy of Sciences at 
Stockholm in December last, now issued by Messrs. 
Barth, Leipzig, Prof. W. Wien gave a valuable survey 
of the recent advances made by the theory of radiation 
and of the difficulties which still beset it. Lord Ray- 
. 
’ Baa 
leigh’s form of the law of radiation of a black body, | 
based on the equal distribution of the energy amongst 
the degrees of freedom of the vibrating system, agrees 
with observation over the longer wave-lengths only. 
Prof. Wien’s formula, based on his ‘‘law of displace- 
ment” or compression of radiation, agrees, on the 
other hand, with measurements over the shorter wave- 
lengths only. 
with observation over the whole of the range of 
wave-lengths at present available, but rests on the 
conception of energy as atomic in structure. The 
difficulties which such a conception raises are very 
grave, and Prof. Planck himself has substituted con- 
tinuous for discontinuous absorption of radiation (see 
these ‘‘Notes’”’ for March 16, p. 90, and June 15, 
p- 528, 1911), while Sir Joseph Larmor devoted his 
Bakerian lecture in 1909 to a possible alternative. Prof. 
Einstein’s attempt to bring Dulong and Petit’s law of 
atomic heats under Planck’s theory has met ‘with 
partial success only, and Prof. Wien thinks the pro- 
cesses going on in the atoms themselves must be 
taken into account before the theory of radiation can 
be placed on a satisfactory footing. 
has already been made by Prof. Sommerfeld, who 
gives the constant h of Planck’s theory an atomic 
significance. 
AN interesting series of papers on the chemical 
effects of light on organic compounds appears in the 
NO. 2215, VOL. 89] 
Prof. Planck’s form of the law agrees | 
A commencement | 
Gazzetta chimica Italiana (vol. xlii., p. 65 et seq.)- 
In the first paper, by Prof. Paterno and C. Maselli, 
the synthesis is described of a substance having alka- 
loidal properties, by exposing acetophenone dissolved 
in alcoholic ammonia to bright sunlight during several 
months. The alkaloid C,,H,,N. forms well-defined 
measurable crystals, and appears to owe its origin to 
a complex change in which two molecules of acetone, 
two of ammonia, and one of alcohol are involved. 
In the absence of light the alkaloid is not formed. 
In the later papers, by L. Mascarelli, a striking change 
brought about in aromatic aldehydes by traces of 
iodine under the influence of sunlight is dealt with. 
It has been known for some years that benzaldehyde 
polymerises to trimeric and tetrameric forms under 
the influence of the sun’s rays; it is now shown that 
in the presence of traces of iodine a dimeric form is 
produced which has the structure of benzyl benzoate. 
There has, in fact, been reduction of a portion of the 
benzaldehyde at the expense of the remainder, a result 
similar to that well known to be induced by the action 
of alkalies, such as potassium hydroxide. 
In the January number of the Bulletin de la Société 
@ Encouragement pour l’Industrie Nationale, M. H. 
Gault gives a summary of the additions which have 
been made during the last few years to our knowledge 
of natural perfumes and other essential oils. Among 
the principal oils dealt with are those of cloves, 
eucalyptus, fennel, juniper, geranium, jasmine, 
lavender, lemon grass, and peppermint. The article 
is a continuation of one on the same subject published 
in 1908. Various sources have been drawn upon for 
the information, Schimmel’s ‘bulletins’ figuring 
frequently in the references, which include also a fair 
number of English and American periodicals. A short 
account of the origin of each oil is given, with par- 
ticulars of its physical and chemical characters, in- 
cluding its density, boiling point, refractive index, 
rotatory power, saponification value, and so on; 
usually also the chief chemical components are indi- 
cated. Special points in the chemistry of individual 
oils are discussed incidentally, but the author reserves 
for a future article the more general consideration of 
the chemical constituents of essential oils, as well as 
a fuller discussion of certain researches. To those 
interested in the subject the contribution will be useful 
as a convenient résumé of investigations, the accounts. 
of which have been disseminated hitherto over a 
number of publications. 
Butietin No. 52 of the University of Illinois con- 
tains an account of investigations of the strength of 
rolled zinc carried out by Mr. Herbert F. Moore. 
From the results it appears that zinc, either rolled 
or cast, has no well-defined yield point, and its elastic 
limit is very low. Zinc possesses a relatively high 
degree of plasticity. The ultimate strength of thin 
rolled zinc plate (not more than o'05 inch thick) is 
about 24,000 Ib. per sq. in. The modulus of elasticity 
of zinc in tension is about 11,500,000 Ib. per sq. in. 
The stress per square inch of area sheared developed 
| in punching or shearing rolled zinc plates is about 
40 per cent. of the stress developed in punching or 
shearing mild steel plates; the ‘energy required in 
