OcTOBER 23, 1yo2| 
NATURE 
637 
** Agricultural Statistics of India for the years 1896-97 to 1900- 
ot.” The numerical data have been compiled under the}super- 
vision of the Director-General of Statistics and are issued in two 
parts, the first dealing with British India and theJsecond with 
native States. The information is tabulated under fourteen 
headings, including, among others, tablesishowing the total area 
of districts ; the amount of cultivated and culturable land ; tthe 
gross cultivated area under each crop; agricultural stock ; the 
principal varieties of tenure held direct from the Government ; 
the progress made in the production of tea and of {coffee ;-tand 
the average yield per acre of the principal crops. The tables 
are accompanied by numerous short, explanatory (notes which 
are often of an interesting nature. The following statistics 
referring to the cultivation and production of indigo in British 
India during the past few years show that a remarkable decline 
has occurred, doubtless in consequence of the competition of the 
artificial product :— 
Year. Accents Bisa 
1897-1898 1,339,099 166,812 
1898-1899... -- 1,010) 305i tee .---139,320 
1899-1900 5 1,026,900 .... ... 111,890 
BOOO TOON creas ccsaseses <2 (OOO. 7 mere .148,029 
(000) > (0\0y ere 803,697 ..... -121,475 
AN important addition to the literature of the Myxomycetes 
will be found in the ‘‘ Monograph of the Acrasiez,’’ by Mr. 
E. W. Olive. The paper, which is publishedin the Proceedings 
of the Boston Society of Natural History, provides a critical 
summary of the data furnished by previous writers and the 
results of the author's investigations. .Mr. Olive follows Zopf 
in uniting the groups of the Labyrinthulee and Acrasiez under 
the title of the Suorophorez, which are related to, but more 
primitive than, the true Myxomycetes. 
A NEW edition of the first volume of Mr. William Scott 
Taggart’s ‘ Cotton Spinning” has been published by Messrs. 
Maemillan and Co., Ltd. The book deals with all processes in 
cotton spinning up to the end of carding. 
THE lecture arrangements at the London Institution, Fins- 
bury Circus, for the session 1902-3, have now been announced. 
The list includes lectures by Lord Avebury, on ‘‘ The Scenery of 
Iingland and the Causes to which it is Due”; by Sir Robert 
Ball, F.R.S., on ‘“‘The Earth’s Beginning” ; by Dr. A. Smith 
Woodward, F.R.S., on ‘‘ Some newly discovered’ Extinct 
Animals” ; by Prof. S. P. Thompson, F.R.S., on ‘* The Magic 
Mirror” ; by the Rev. W. H, Dallinger, F.R.S., on ‘‘ Recent 
Studies in the Lives of Spiders”; and by Dr. W. Hampson, 
on ‘‘ Liquid Air,” The lectures are held on Monday evenings 
at 5 o'clock and on Thursday evenings at 6 o'clock, 
MEssrs. MACMILLAN AND Co., LYD., have published a small 
collection of mathematical tables for ready reference compiled by 
Mr. Frank Castle and printed on stout paper. The booklet 
costs 2d., and contains useful numbers and formule, tables of 
logarithms and anti-logarithms, as in similar tables published by 
the Board of Education, together with tables of natural sines 
and tangents for every five minutes of arc. In view of the 
encouragement now being increasingly given to the use of 
logarithmic and trigonometric tables at an early stage of 
mathematical instruction in schools and colleges, the collection 
should prove of use to teachers and students alike. 
AN elaborate catalogue of balances and weights, containing 
more than one hundred pages’ and two hundred illustrations, 
has been published by Messrs. F. E. Becker and Co., of 
Hatton Wall, London, Balances and weights suitable for 
scientific work of every kind are described in the catalogue, and 
the prices at which they can be obtained are remarkably low in 
comparison with those of a few years ago. 
NO. 1721, VOL. 66] 
The quantitative 
work now carried on in the physical and chemical laboratories 
of schools has greatly increased the demand for students’ 
balances sensitive to a milligramme or two, no less than six 
thousand of such balances having been introduced lately into 
Irish elementary schools. It is impossible to over-estimate the 
educational value of practice in the use of accurate. balances, 
and by producing such instruments at reasonable prices firms 
like Messrs. Becker and Co. have done much to facilitate the 
introduction of such work into the school course. 
THE existence of a pentafluoride of iodine was indicated by 
Gore and by MaclIvor thirty years ago. On account of its bear- 
ing on the question of the valency of iodine, a further examin- 
ation of the behaviour of this fluoride seemed desirable, and in the 
current number of the Comptes rendus M. Henri Moissan gives 
an account of its preparation and properties. The compound is 
obtained without difficulty in a perfectly pure state by the action 
of fluorine upon solid iodine, and forms a colourless liquid, 
solidifying at 8° C. and boiling without change at 97° C. 
Analyses show that the fluoride has undoubtedly the composition 
IF;, and it is noteworthy that it can be distilled in a current of 
hydrogen without any reaction taking place. This fluoride 
possesses very great chemical activity ; most elementary bodies 
decompose it, and it produces with compound bodies a large 
number of double decompositions. Iodine pentafluoride is de- 
composed at about 509° C., iodine being formed, and possibly a 
new fluoride of iodine. 
IN the current number of the Zeztschrifl frir physikalische 
Chemie is an interesting paper by Mr. A. A. B'anchard on the 
decomposition of ammonium nitrite in aqueous solution by which - 
reaction nitrogen is liberated. It is found that this decom- 
position only takes place with sufficient rapidity to enable the 
velocity to be determined under the influence: of hydrogen ions 
or free nitrous acid. In these circumstances, the velocity 
with which nitrogen is evolved is proportional to the concen- 
tration of the ammonium ions and of the nitrite ions, being 
increased by the presence of other ammonium salts or nitrites, 
and the hydrogen ions have an accelerating effect on the 
reaction. 
Ir has been known for some time that the! compounds which 
the albuminoids form with acids and bases are of true salt-like 
character. The aqueous solutions of these compounds are 
conductors of electricity, and presumably, therefore, contain 
electrically charged ions. In the current number of the 
Zeitschrift fiir physikalische Chemie, Dr. 'Sackur gives an 
account of experiments which he has made on aqueous solutions 
of casein sodium. From the variation of the conductivity with 
the dilution, the author concludes that casein is a tetrabasic acid 
with a molecular weight equal to 4540. Experiments on the 
diffusibility of casein sodium indicate that, although an 
electrolyte, it is incapable of passing through parchment paper, 
and in this respect therefore behaves as a colloid. 
In the Journad of the Chemical Society, Messrs. Chapman and 
Lidbury give an account of some interesting experiments on the 
decomposition of water vapour by the electric spark. A series 
of electric sparks was allowed to pass between two platinum 
wires sealed into a glass tube through which a current of water 
vapour was drawn. The gases from the anode and kathode 
sections of the tube were collected separately. As a result of 
the examination of the gases thus collected, the authors conclude 
that the separation of the constituent elements of water from 
water vapour is not entirely due to a process of electrolysis. If 
it were, hydrogen should appear at one electrode and oxygen 
at the other, whereas hydrogen collects at both electrodes: The 
quantities of the separated gases should, moreover, not exceed 
those of the oxygen and hydrogen, which collect in a voltameter 
