DeEceMBER 31, 1896] 
NATURE 207 
have been discovered within the last two centuries, since the 
time of Ray. The earliest records are by Turner, 1538-1568, 
who seems to have known about 230 species; by Ray’s time 
this had been increased to 725; and he brought the number of 
British flowering plants up to 930. 
AN interesting fact in connection with the Schwendenerian 
theory that lichens are compound organisms consisting of an algal 
and a fungal constituent, which carry on a mutually symbiotic 
existence, is contributed to Ze Botanzste in a paper by M. P. A. 
Dangeard. He states that a common and destructive disease of 
‘the Lombardy poplar in Italy is caused bya species of Cadécéun 
which he finds on the living branches, and which he names C. 
populneum. The genus is usually placed among the lichens ; 
but this species is a pure fungus, destitute of any algal con- 
stituent, and carries on a parasitic life on the living tissues of 
the host. 
A very remarkable degradation of the ovule takes place in 
some genera of parasitic plants, and is especially described by 
M. P. van Tieghem in a paper in the Az//e/zx of the Botanical 
Society of France, in the case of some Balanophoracez and 
Loranthacez. In one section of the former order there is in each 
carpel a single hypodermal endosperm-mother-cell which be- 
comes the embryo-sac. A similar phenomenon occurs in A7cev- 
thobium among Loranthacee, where two’ endosperm-mother- 
cells are produced at opposite sides of the ovarian cavity, and 
where, therefore, there is a placenta, but no ovules. In Ba/ano- 
phora the reduction is carried still further; the monocarpellary 
ovary produces beneath the epiderm a single endosperm-mother- 
cell; there is, therefore, here neither ovule nor placenta. 
This reduction of the ovule is frequently accompanied, 
especially in certain genera of Loranthacez and Balanophoracee, 
by a peculiarity in the mode of impregnation, which van 
Tieghem terms (in'a paper in Morot’s Journal de Botanigue) 
bastgamous, in contrast to the usual acrogamous mode. The 
ordinary position of the ‘‘ egg-apparatus” or embryonic vesicles 
and of the antipodals is here reversed, the former being located 
at the lower, the latter at the upper end of the endosperm- 
mother-cell. This fact seems to confirm the theory that there is 
no physiological difference between embryonic vesicles and anti- 
podals, except that the former are usually active, the latter 
inactive. 
THE Austrian Meteorological Society has published an index 
‘to the first twenty volumes of its Zeztschrzft. The work has 
been prepared by Dr. S. Kostlivy in a very careful manner as a 
mixed author and subject catalogue, arranged alphabetically. It 
is well known that the Zez¢schrzft, which was edited by the late 
Dr. Jelinek and by Dr. J. Hann, is a complete repertorium of 
climatology and terrestrial magnetism for all parts of the globe. 
This handy index, referring to the years 1866-85, will therefore 
be a boon to scientific men who may wish to obtain the results 
of observations made in any particular locality, without the 
trouble of referring to, and reducing the original records. 
THE Meteorological Observatory of Upsala has published a 
series of concise tables for photogrammetric measurements of 
clouds. The usual calculations for determining the height of 
clouds are always tedious, especially when the photogrammetric 
method is employed, which, although it renders much greater 
precision possible than direct methods without photography, 
introduces fresh corrections and reductions. The tables in 
question, which have been calculated by Mr. J. Westman, will 
be found useful for the solution of the trigonometrical values of 
the cloud measurements which are now being specially made in 
various countries, in accordance with the wish expressed at the 
Meteorological Conference at Munich. 
NO. 1418, VOL, 55] 
Mr. W. F. Cray, of Edinburgh, has sent u a copy of a new 
and enlarged reference list (No. 80) of books and memoirs on 
chemistry and the physical sciences generally. Individuals or 
institutions desiring to add important works to their librarie 
should procure a.copy of Mr. Clay’s catalogue. 
THE following are the arrangements for lectures at the Royal 
Victoria Hall, Waterloo-road, S.E., during January, on Tues- 
day evenings, at 8.30 :—January 5, Prof. H. G. Seeley, F.R.S., 
on the heat of the earth ; January 12, Mr. A. Smith Woodward, 
on Syria and the Syrians; January 19, Mr. A. E. Tutton, on 
the glaciers and snowfields of the higher Alps. 
WE have received the Pagers and Proceedings of the Royal 
Society of Tasmania for 1894-95. The volume contains some 
interesting historical papers: one on the deportation of the 
Norfolk Islanders to the Derwent in 1808, by J. B. Walker ; 
another. on a MS. chart in the British Museum, showing Tas- 
man’s tracks in the voyage of 1642-44, by A. Mault; and a 
third, on early voyages to Papua in 1511 and 1545, by J. R. 
McClymont. A large number of field observations in botany, 
geology, zoology and ornithology are put on record, and Mr. 
H. C. Kingsmill gives an account of meridian observations with 
the Hobart transit instruments. The Society is largely interested 
in Antarctic exploration, and in the extension of the Australian 
meteorological service. 
AN important addition to the synthetical methods for the 
preparation of carboxylic acids has been made by Messrs. Bredt 
and Kallen, whose work is recorded in the last instalment of the 
Annalen. They have found that unsaturated acids which con- 
tain two negative radicles united with one of the unsaturated 
carbon atoms readily unite with the elements of hydrocyanic 
acid, when the corresponding ethereal salt is boiled with a solu- 
tion of potassium cyanide in dilute alcohol. Ethyl benzylidene- 
malonate, for example, which is formed by the condensation of 
benzaldehyde with malonic ether, is thus converted, with the loss 
of a carboxyl-group, into ethyl 8-phenyl-cyanopropionate, 
C,H,.CH(CN).CH,.COOC,H,, from which phenylsuccinic acid 
can easily be prepared. Certain unsaturated lactones, such as cou- 
marin, also readily.unite with hydrocyanic acid in this way, and 
there can be little doubt that the new reaction will prove of 
immense importance in the development of our knowledge of 
the carboxylic acids. 
OwI1NnG to the fact that lithium is the only substance with which 
nitrogen will directly combine at ordinary temperatures, consider- 
able interest attaches to the properties of the compound thus 
formed, lithium nitride. This compound, as M. Guntz showed 
some months since, is easily prepared by the combustion of lithium 
in nitrogen gas, and the specimen thus obtained was regarded as 
pure, since the nitrogen absorbed corresponded almost exactly 
with that required by the formula LizsN. But in spite of this 
coincidence M. Guntz now shows that the product is not pure, as 
at the moment of combination the lithium attacks the boat in 
which it is held, although it is difficult to say exactly in what 
form the metal goes into solution in the molten nitride. Thus 
working with iron boats, the nitride contained from 2 to § per 
cent. of iron, and nickel is even more strongly attacked. Silver, 
platinum, quartz, and graphitic carbon were all tried, and found 
to be even less suitable than iron. Measurements of the mole- 
cular heat of formation of the nitride gave a value of 49°5 
calories, or less than the value for the equivalent quantity of 
lithium hydride (65 calories). From this the conclusion was 
drawn that hydrogen ought to decompose the nitride of lithium 
with formation of the hydride, and this was found to be the case. 
The reaction, however, can be reversed, since at a high tempera- 
ture a stream of nitrogen converts the hydride into the nitride. 
