FEBRUARY 21, 1907] 
NATURE 
401 
growth ef a crested variety of bracken at Faygate, Sussex. 
Other papers in the same journal include an article on 
horticulture in relation to medicine, and notes on tufted 
pansies, hollies, and the ideal potato. In the first named 
Mr. E. M. Holmes furnishes a list of plants now culti- 
vated as herbs, among which one unexpectedly finds the 
nettle and mallow; an account of medicinal plants suit- 
able for cultivation in this country is also given. 
AccorpING to the report of the Department of Agri- 
culture in the Madras Presidency for 1905-6, a large ex- 
perimental area has been acquired at the village of Tali- 
peramba, in the Malabar district, for growing pepper 
vines with the object of studying their morphology, 
varieties, and other problems connected with their cultiva- 
tion. Under the control of Mr. C. A. Barber, the results 
are likely to add materially to our knowledge of this 
historically and economically interesting product, and will, 
it is hoped, resuscitate the industry in South India. Other 
important products receiving attention are sugar-canes, 
ground-nuts, cotton, and tobacco, but experiments are not | 
sufficiently advanced to furnish conclusions. The manu- 
facture of door-mats, napkins, and muslins from the fibre 
of Agave vivipara is an extension of the usual applications 
of this fibre. 
Tue Cycads are so few in number, and they occupy 
such an important position in plant taxonomy, that a 
paper embodying new researches ciinnot fail to be interest- 
ing. As the outcome of an expedition to Chavarillo, in 
the Mexican tropics, Prof. C. J. Chamberlain was able to 
secure material of the little-known ovule of the genus 
Dioon, and his tesults are published in the Botanical 
Gazette (November, 1906). The author obtained a series 
of stages from the appearance of the archegonium initial 
cell to the germination of the seed. The archegonia are 
formed in October to the number of four or five in each 
ovule; a neck cell is cut off, and subsequently a ventral 
canal nucleus separates mitotically from the egg nucleus. 
Haustoria are deyeloped in connection with the transference 
of nourishment to the egg cell. The nucleus of the ovum 
is the largest known in plants, and contains twelve chromo- 
somes. Incidentally, the author concurs with the opinion 
that plants of Dioon may continue to live for a thousand 
years. 
A NEW journal bearing the title Gazeto 
Internacia is to be published in Esperanto. It will con- 
tain original articles on theoretical and applied mathe- 
matics, mechanics and theoretical physics, reprints of 
articles published in other languages, reviews, corre- 
spondence biographies, and papers on the history and 
teaching of mathematics. It is not intended to compete 
with, but rather to supplement and strengthen, existing 
journals. The publisher is F. J. Mathenesserlaan 
290, Rotterdam. 
Vaes, 
Mr. B. M. Duccar details some experiments to ascertain 
the value of the osmotic pressures in the cells of certaim 
marine alga in a paper published as vol. xvi., No. 8, of 
the Transactions of the Academy of Sciences in St. Louis. 
Common salt, nitre, and sugar were used to make plasmo- 
lysing solutions, both in distilled and sea-water. It was 
found that the amount of nitre in sea-water required to 
plasmolyse together with the equivalent value of the salts 
in the sea-water was less than the amount in the fresh- 
water plasmolysing solution, while the reverse held good 
for sugar. 
adding to sea-water additional amounts of the different 
NO. 1947. VOL. 75 | 
| Dallmeyer, 
An attempt to examine the toxic effects of | 
constituent salts occurring in sea-water elicited the facts 
that salts, ordinarily to 
and fresh-water algze, were almost inert, and ammonium 
compounds were the most active. 
magnesium toxic phanerogams 
From Messrs. Burroughs, Wellcome and Co. we have 
received a copy of the 1907 edition of their ‘‘ Photographic 
Exposure Record,’’ which is familiar to most of our photo- 
graphic readers. It is bound in art-green canvas, and is 
issued at a shilling. This pocket-book has been 
brought well up to date, and, as we have pointed out on 
previous occasions, should be the vade mecum of every 
photographer. Even in this small compass a great amount 
of useful information is compressed, in spite of increased 
space being provided this year for the record of negative 
exposures, there being room now for 336 entries. Each 
card for hanging up, 
which gives useful information regarding the timing of 
neat 
copy is accompanied by a folding 
development by the factorial method for various degrees of 
contrast, and particulars of equivalent plate-speed numbers 
according to the different systems in use. 
series of examples illustrates the article on exposure. 
An entirely new 
Mr. Joun C. Packarp, of the High School, Brookline, 
Mass., sends us a description of an apparatus he has 
devised to determine the resultant of two motions at right 
angles to one another, one uniform, the other uniformly 
accelerated. A steel ball, 1 inch in diameter, is placed 
at the top of an inclined plane of plate glass, and is made 
to acquire a uniform motion in a horizontal direction by 
being rolled down an auxiliary incline behind a ledge; the 
ball is then allowed to roll down the glass plane. A 
tracing of the curve generated by the ball is secured by 
fixing a sheet of squared paper to the plane and a piece 
of soft carbon paper over it. The ball in rolling over the 
carbon paper leaves its. trace on the squared paper beneath. 
A study of the-curve thus generated enables the pupil to 
arrive at the laws of uniformly accelerated motion. 
A rourtTH edition of an ‘‘ Introduction to Physical 
Chemistry,’’ by Prof. James Walker, F.R.S., has been 
published by Messrs. Macmillan and Co., Ltd. The work 
has been enlarged by the inclusion of sections dealing with 
the behaviour of radio-active elements, atomic and mole- 
cular and and  salt-hydrolysis. 
dimensions, neutrality 
Mintoniankanl Newer data afforded by recent researches have been sub- 
stituted for the numerical values of previous editions. 
We regret that in a short notice of Prof. G. S. Boulger’s 
work on ‘ Familiar Trees,’? in Nature of January 31, 
the reviewer was under a misapprehension when he re- 
marked that certain trees had been omitted. The book 
reviewed is only the first volume of a new edition of 
Prof. Boulger’s work, which is still being issued in fort- 
nightly parts, and the missing species will be dealt with in 
another volume. The volume should, we consider, have 
been described as vol. i. on the title-page instead of using 
the words ‘‘ First Series.”’ 
Tue authorities of the British Museum (Natural History) 
have recently adapted the telephoto lens for securing 
accurate photographs of specimens. The installation con- 
sists of a 12X10 camera with an extension of 4 feet, 
fitted with an 18x16 rectilinear lens and telephoto attach- 
ment, the whole apparatus being made by Messrs. J. H. 
Ltd. It successful, the 
improvement in perspective and depth of definition in the 
photographs being very noticeable when compared with 
those taken on the same scale with an ordinary lens. 
has proved very 
