Juty 3, 1902] 
Talbot and J. W. Brown, and forms part of vol. xli. of Smith- 
sonian Miscellaneous Collections. The same volume contains a 
compilation of the statistics of the chemical societies of the 
world for the year 1900, by Dr. H. C. Bolton. 
ACCORDING to a new patent of the Chemische Fabrik 
Griesheim-Elektron, lead dioxide is now produced electro- 
lytically from a solution of an alkali chloride in which litharge 
is suspended. The dioxide is formed at the anode by the action 
of nascent chlorine and sodium hypochlorite on the sodium 
plumbite produced from the litharge and the sodium hydroxide 
set free at the kathode. No loss of chlorine takes place at the 
anode during this electrolytic process. 
VOL. xxxvii. of the Proceedings of the American Academy 
of Arts and Sciences contains the results of an investigation of 
the decomposition of mercurous chloride by dissolved chlorides, 
by Messrs. T. W. Richards and E. H. Archibald. It is shown 
that this decomposition is quite considerable if the chloride 
solutions are fairly concentrated, a point of considerable import- 
ance in the analytical determination of mercury as mercurous 
chloride’ The action is not of a catalytic nature, but a definite 
condition of equilibrium is set up, the dissolved mercury 
existing probably in the form of a complex ion represented by 
the formula HgCl”, in the solution. 
WHILE admitting that the evidences of embryology, vestigial 
traces, and geographical distribution have rendered it indisputable 
that species have arisen in our world, not through creation in 
each fresh case, but through descent from other kindred species 
with variation, Mr. James B. Johnston maintains, in an article 
“* What About Natural Selection ?” in the Contemporary Review 
for July, that the proved influence of natural selection is being 
written down as less and less every day. The article is 
concerned only with the evidence of palzeontology. 
THE additions to the Zoological Society’s Gardens during the 
past week include a Vervet Monkey (Cercopithecus /alandit) 
from South Africa, presented by Mr. J. M. Hemingway ; an 
African Tantalus (Pseaudotantalus ibis) from West Africa, 
presented by Mr. C. T. Reaney; two Black Salamanders 
(Salamandra atra), an Alpine Newt (A/olge alpestris) from the 
Alps, presented by the Rev. J. W. Horsley ; a Common Viper 
(Vipera berus) British, presented by Mr. E. Ball ;a Chacma 
Baboon (Cynocephalus porcarius), a Natal Sternothere 
(Sternothoerus stnuatus), from South Africa, a Ludio Monkey 
(Cercopithecus Iudio) from West Africa, two Grey Lemurs 
(Hapalemur griseus) from Madagascar, two Azara’s Opossums 
(Didelphys azarae) from La Plata, a Botta’s Snake (Uharina 
bottae) from North America, deposited. 
OUR ASTRONOMICAL COLUMN: 
CHANGES ON THE Moon.—The June number of the Cenéury 
Magazine contains a popular account of the observations of the 
moon made by Prof. W. H. Pickering at Flagstaff, Arizona, and | 
Jamaica, illustrated with pictures from drawings and photographs. 
Previous workers have already shown that some markings on the 
lunar surface were in all probability of a variable nature, but the 
new observations demonstrate beyond doubt that the surface of 
the moon is subject to distinct changes, and Prof Pickering gives 
some very decisive instances where radical alterations have 
actually been observed. Attention also is drawn to the existence 
of seas, canals and lakes on our satellite’s surface, terms which 
have very generally been adopted with reference to the planet 
Mars, but which are employed here with the full understanding 
that they do not imply in any way the existence of water in the 
liquid form. These canals are described as being smaller than 
those on Mars, but broader in proportion to their length ; in 
colour they are grey and yellowish-white. Many of the changes 
on the lunar surface are caused by the growth, as Prof. Pickering 
states, of the lunar vegetation itself, and hé quotes a particular 
NO. 1705, VOL. 66] 
NATURE 
23) 
region situated just to the right of the central peaks of Eratos- 
thenes where he observed the most marked change ; reference 
is further made in some detail to the changes observed in some of 
the canals and lakes. The importance of these observations to 
selenography and the great interest attaching to them should 
undoubtedly stir up a new desire in many workers to follow and 
continue these researches, which require no very great instru- 
mental equipment. 
REMARKABLE NAKED EYE NEBULOsITY.—Mr. W. H. 
Robinson, writing from the Radcliffe Observatory, Oxford, 
sends us a description of a curious object observed by him on 
May 28. Whilst observing with the Radcliffe transit circle at 
1th. 19m. G.M.T., his attention was directed to a nebulous 
object about eight degrees from the zenith. ‘* It was small, but 
bright and well defined, elliptic in form (major axis 2°, minor 
axis 1°°5), and situated about half-way between 7 Ursze Majoris 
and a Lyre, but a few degrees south. The object very much 
resembled the Praesepe when that cluster is visible in a some- 
what hazy sky, an atmospheric condition which prevailed at this 
time, At first I supposed the object to be acomet, but was 
soon disillusioned on this point, for in a few minutes its evan- 
escent character was revealed, and, gradually fading, by 11.30 
G.M.T. it had entirely disappeared.” 
The position of the nebulosity was found by means of a star 
atlas to be 
R.A. 16h. 15m. 
Decl. + 44°. 
The sky was watched until midnight for any return of the 
phenomenon, but nothing was seen except at about Ith. 42m., 
when a faint patch of light appeared for a few seconds only, 
about two degrees east ot the above position. The luminosity 
was apparently not of an auroral nature, and Mr. Robinson 
suggests that it may have been the trail of a meteor, several 
instances of meteor clouds of this character having been re- 
corded. 
Other observations of the object observed on May 28, if 
forthcoming, would probably enable a determination to be made 
of its distance and nature. 
A THEORY OF VOLCANOES.—In a forcible exposition of a 
theory which supposes high-tension terrestrial electricity to be 
the immediate cause of volcanic eruptions, M. A. Taquin, in 
the Revue Sctentifigue for June 14, brings together some re- 
markable observations of the connections between volcanic, 
solar, magnetic, and terrestrial electrical phenomena. The 
author provides for the disruptive forces and the heat which 
attend volcanic actions, by the discharge of this high-tension 
electricity, and then connects this electricity with the previously 
observed relations between solar, and terrestrial electrical and 
magnetic phenomena. 
M. Taquin accounts for the remarkably sudden deaths of the 
inhabitants of St. Pierre by supposing that they were electro- 
cuted, and proceeds to urge, in the following words, the estab- 
lishment of observatories in volcanic districts:—‘‘I am 
convinced that the study of the manifestations of terrestrial 
electricity in such districts will give us the means of foreseeing 
these volcanic eruptions.” 
THE FRENCH GEODETIC MISSION TO THE EQUATOR,— 
Commandant Bourgeois gives an interesting and detailed 
account of the first year’s work of the French geodetic expedi- 
‘tion in the Bulletin de la Société Astronomiqgue (June, 1902). 
M. Bourgeois first explains that the vazson d ére of the mission 
is ‘to determine certain elements by which to calculate the 
dimensions of the earth,” and he then proceeds to answer the 
following self-imposed questions :—(1) What are these elements ? 
(2) How are they to be determined? (3) Why is it necessary 
to make the observations in a place which is so distant and so 
difficult to reach? In answering these questions the author 
describes the inauguration, the organisation, and the journey of 
the mission to Riobamba, Ecuador, S.A., and also explains why 
Riobamba was fixed upon as the centre of operations. The 
whole report, which was communicated to the Société Astro- 
nomique, gives an instructive account of the work already 
achieved, and is illustrated by photographs which give the reader 
a clear idea of the methods pursued by the mission. 
OBSERVATIONS OF NOVA PERSEI.—In No. 3796 of the 
Astronomische Nachrichten, Prof. E. E. Barnard gives a brief 
résumé of the various observations of the Nova which were 
made at Lick subsequent to july, 1901, 
