32 NATURE 

furnish a trustworthy accelerated test for fatigue 
resistance. It is stated that “‘ this report contains 
the most valuable and complete information ever 
published on this subject.’’ We shall await its appear- 
ance with much interest. 
Owing to the very sudden increase in the destruc- 
tion of marine piling in San Francisco Bay resulting 
from the attack of marine borers, which amounted 
in value to about 15,000,000 dollars in the last year 
or two, a marine laboratory has been established 
in San Francisco Bay and the National Research 
Council has taken measures for undertaking co- 
ordinated investigations on the problem. The 
report states: “‘ This is one of the most important 
problems presented to the National Research 
Council since its organisation and one of the best 
illustrations of the important service which can be 
rendered by a national body of this sort. It is also 
an excellent illustration of the need for co-opera- 
[JANUARY 6, 1923 
tion between the scientific and engineering groups.” 
The committee on ceramic research has selected 
the following four subjects to receive early atten- 
tion: (1) A study of the elements which determine 
the plastic nature of clay ; (2) a critical examination 
of certain methods used in silicate analysis; (3) a 
study of American pot clays and their proper com- 
pounding for the production of refractories used in 
the glass industry; (4) a study of the relationship 
between crazing and the expansion coefficients of 
bodies and glazes. 
Enough has been indicated of the character of 
this sixth annual report of the National Research 
Council to convince, perhaps, even the warmest 
exponent of the theory of science for science’s sake 
and of the inalienable right of the scientific spirit to — 
go whither it will, that there is a vast field of 
scientific research meet for organised co-operation on 
national lines. J. W. W. 
International Contributions to Mendelism. 
"THE Dutch journal Genetica, under the editorship 
of Dr. Lotsy and Dr. Sirks, has published an 
excellent international number as a Mendel Memorial 
in connexion with the recent centenary celebrations 
in Briinn and Vienna. Ina long and carefully written 
article, Prof. V. Hacker (Halle) reviews the present 
state of knowledge of Mendelian inheritance, especially 
as regards cytological interpretation and other aspects 
of general interest. Such a cautious and well-informed 
statement is most valuable at the present time. Dr. 
E. Fischer (Ziirich) describes his large series of ex- 
periments in breeding the Silver-washed Fritillary 
(Argynnis paphia) and its dimorphic female, the well- 
known var. valesina. It used to be thought difficult 
to get such creatures to breed in confinement, but 
Dr. Fischer, following a technique which he describes, 
has raised several thousands as the result of various 
matings. Prof. R. Goldschmidt (Berlin) contributes 
an analysis, and suggests a factorial scheme which 
fits the numbers fairly well. There is a dominant 
valesina factor, V, which is not sex-linked, and the 
combinations VV, Vv, vv are possible both in males 
and females. Since, however, the males are all paphia 
alike, their genetic constitution can be decided only 
by experimental breeding. We are still as far as 
ever from understanding how it comes to pass that 
the males are thus uniform, though they may contain 
even two doses of the element which in a single dose 
suffices to give the dominant character to the female, 
a difficulty which has puzzled geneticists very long. 
There are many parallel examples in butterflies of 
di- and polymorphic females, though nothing analogous 
is ever seen in the males. The cytological scheme 
which so successfully represents the observed facts 
in colour-blindness- and similar examples here ap- 
parently fails, and the special interpretations offered 
by Goldschmidt, though suggestive, are scarcely more 
than a restatement of the difficulty. 
Prof. Ghigi (Bologna) discusses the origin of 
domesticated poultry, especially fowls and pigeons, 
in the light of his breeding experiments. He leans 
to the conclusion, which other evolutionists have also 
reached, that it is most difficult to suppose, as Darwin 
did, that the various breeds of fowls are derived 
simply from Gallus bankiva, or the pigeons collectively 
from the rock-dove. The plausible suggestion is here 
- made that the heavy breeds of fowls, which constitute 
the main problem, may have come from some partially 
flightless island form, taken bodily into domestica- 
tion, since nothing of the sort now survives in a wild 
state. Some of the pigeons, he thinks, may be 
derived from crosses with Columba leuconota, which 
when bred with tame pigeons gives, as he found, at 
least fertile males. The effect of all these appeals 
to|multiple origins, necessary as they now appear to 
be, is to weaken confidence in the classical deductions 
as to unlimited possibilities of variation under 
domestication apart from cross-breeding. 
Other interesting papers are those of Prof. J. L. 
Frateur (Louvain) on compound characters, M. A. 
Meunissier (Paris) on the 3-podded and other varieties 
of peas, and Dr. Winge (Copenhagen) on some curious 
and complex phenomena in Drosophila, which favour 
the hypothesis already entertained by several biologists 
that mutation may sometimes be the consequence of 
a rare cross-over. Dr. Sirks (Wageningen) recounts 
his experiments with a new subspecies of Linaria 
vulgaris, giving a mixed F, generation in crosses with 
the wild type, an unexpected result which may be 
variously interpreted. A remarkable experiment is 
also described by Prof. J. Schaxel (Jena), whp suc- 
ceeded in grafting together limb-buds of the coloured 
and the white forms of Axolotl, producing limbs 
compounded of both elements so intimately associated — 
that the name “‘ Chimera ’’ may be applied to them, 
on the analogy of Winkler’s famous graft-hybrids 
made between the tomato and Solanum nigrum. 
This collection of memoirs reaches an unusually 
high level. All contain material of permanent 
value. 

The Oldebroek Explosion of October 28, 1922. 
N Nature of November 4, p. 619, a preliminary 
note appeared on the great explosion at Olde- 
broek. It is now possible to discuss more fully the 
results obtained. 
About 140 reports were received from observers in 
the British Isles. Of these, nearly one-third stated 
that despite careful listening they heard no sound 
that appeared to be due to the explosion. 
NO. 2775, VOL. 111] 
When the distribution of the positive and negative 
reports is studied, the most notable feature is the 
entire absence of positive reports from the greater 
part of the Midlands of England. With regard to 
Europe generally, it appears that the sound was 
reported so far off as 850 km. to E.S.E., 600 km: to 
S. and 7oo km. to N.W. of Oldebroek, whereas no 
single trustworthy observation was reported in a zone 
