538 
NATURE 
[January 8, 1914 
fellow twin of which is a normal male. The true 
nature of the free-martin is revealed by its possessing’ 
the essential internal generative organs of the bull, 
although these are accompanied by the external 
accessory organs of a female, while a rudimentary 
vagina and uterus are also present. From the article 
on sheep we regret to learn that the number of head 
in Great Britain continues to show a serious decrease. 
THREE papers on osmotic pressures in plants, by 
Prof. H. H. Dixon and Mr. W. R. G. Atkins, have 
recently appeared in the Proceedings of the Royal 
Dublin Society, vol. xiii. (1913). The authors show 
that the sap pressed from living, untreated tissues 
does not give a true estimate of the concentration of 
that in the vacuoles of the cells before the application 
of pressure, that in order to extract the sap from the 
cells without altering the concentration it is necessary 
to render the protoplasmic membranes permeable, and 
that this can best be effected by the application of 
liquid air. This discovery makes it necessary to 
revise all freezing-point and electrical conductivity 
determinations where expressed sap has’ been em- 
ployed, and the authors find that their new measure- 
ments, making use of sap pressed immediately after 
thawing from tissues frozen solid in liquid air, give 
much higher osmotic pressures than had been obtained 
previously. An important point established is that 
the actual osmotic pressures in the cells are much 
greater than the requirements of the well-known 
cohesion theory of the ascent of sap in trees demand. 
THE potentialities of the British egg and poultry 
trade are indicated in an article, by Mr. Edward 
Brown, in the Journal of the Agricultural Organisa- 
tion Society, vol. vii., Nos. 3 and 4, 1913. Since the 
visit of the first egg and poultry demonstration train, 
three years ago, to three of the counties in South 
Wales the value of the local output has been increased, 
according to a conservative estimate, to the amount 
of 25,0001. to 30,0001. per annum. During April and 
May of last spring a similar train made a twelve days’ 
tour in six counties in North Wales, and was visited 
by more than 19,000 persons. This will suffice to 
indicate the great interest evinced by the general 
public in the question, and such work, educational in 
‘itself, followed by cooperation and organisation in the 
marketing of produce, cannot fail to be of great value. 
It is, however, highly desirable that the continuation 
of this work should be ensured, and that adequate 
official support should be given instead of its being 
dependent on private generosity. 
WE have received from the United States Geological 
Survey three bulletins, namely No. 522, ‘ Portland 
Cement Materials and Industry in the United States,” 
by Edwin C. Sekel; No. 527, ‘‘Ore Deposits of the 
Helena Mining Region, Montana,’”’ by Adolph Knapf; 
and No. 529, ““The Enrichment of Sulphide Ores,” 
by William Harvey Emmons. The first- and last- 
named of these are necessarily of more general in- 
terest than a-description of a specific district can be, 
and whilst the first will particularly interest cement 
makers and engineers in general, the latter appeals 
most strongly to the economic geologist, and student 
NO. 2306, VOL. 92] 
of ore deposition. Although the bulletin upon Port- 
land cement is intended primarily for Americans who 
are either ‘‘owners of lands on which marl, limestone, 
or clay deposits are found,” or ‘*cement manufac- 
turers or those who desire to become such,’’ the 
information conveyed will be found of great use to 
cement manufacturers and users all the world over, 
giving as it does an excellent sketch of the nature of 
cements and the principles of cement manufacture. 
As regards the bulletin by Mr. Emmons, it recapitu- 
lates in a very clear and readable form the present 
state of knowledge concerning the phenomena of 
secondary enrichment of ore deposits, paying par- 
ticular attention to the chemistry of the changes in- 
volved in this enrichment; it deserves the careful 
attention of all mining engineers who have to deal 
with ore deposits liable to be affected by the pheno-. 
mena here discussed. 2 
Mr. R. C. Mossman has contributed to Symons’s 
Meteorological Magazine for December the sixth of 
his interesting articles on southern hemisphere 
seasonal correlations. (1) Argentine Republic and 
Chile: The departure from the normal of the thirty- 
six years, 1876-1911, at certain stations show that 
the winter variations of temperature are generally in 
harmony with each other from May to August. A 
comparison of South American winter temperature 
variations with conditions in other regions yielded 
(with one exception) negative results. (2) Auckland, 
N.Z., and Alice Springs, Australia: On comparing 
the mean temperature at Auckland for the second 
quarter of the year with the values at Alice Springs 
for the last quarter, it was found that from 1892 to 
1906 the former was an index of the latter. (3) 
Sydney, N.S.W., and San Francisco: From 1864 to 
1889 a well-marked relation was apparent between 
the mean temperature at Sydney from May to August 
and the rainfall at San Francisco for October to 
April following. (4) South Orkneys and Kimberley : 
For the years 1903-11 the August and September 
temperature at the former has been a direct index of 
the temperature at the latter during the three months 
following. The temperature at the South Orkneys 
in August and September is largely dependent on the 
ice conditions of the surrounding ocean. The paper 
is accompanied with explanatory tables and diagrams. 
Mr. P. E. B. Jourparn’s “The Principle of Least 
Action” (Open Court Publishing Company, 1s. 6d.) 
is a reprint of three essays published in The Monist 
(1912-13). The first of these is mainly historical, and 
gives an abundance of quotations and references; the 
second deals with extensions of the theory, and alter- 
native ways of considering the problem—in particular 
an outline of O. Hélder’s important theory; the third 
paper is a critical summary. Altogether we have an 
interesting and impartial view of the subject, expressed 
in as simple a form as the nature of the topic seems 
to admit. 
In a pamphlet called ‘‘ Principles of a New Theory 
of the Series,” Mr. F. Tavani has given an interesting 
and apparently novel view of the subject. It has at 
any rate the advantage of making one comparatively 
simple test cover a large number of important cases. 
