94 
NATURE 
[Marcu 26, 1914 
dependence of the temperature. The question as to , Enamel Industry and their Chemical Technology, Dr. 
whether canal-ray ions emit light in the charged or 
the uncharged condition is discussed in the sixth lec- 
ture. Barwald showed in 1911 that a magnetic field 
stops but a small. portion of the light emission, 
whereas most of the positive ions are deflected. This 
tells in favour of the view that the luminous bodies 
are uncharged. Even Reichenheim’s observation that 
the whole of the luminous emission from an alkaline- 
earth anode may be deflected does not invalidate this 
view, since in this case the mean free path was very 
small, and every atom was probably charged at least 
once in the course of its passage. 
THE increasing adaptation of enzymes to chemical. 
purposes is well illustrated by the utilisation of 
urease, by Dr. R. H. Aders Plimner and Miss R. F. 
Skelton (Biochemical Journal, vol. viii., p. 70), in the 
rapid estimation of urea in urine. The action of the 
urease of the soy bean has quite recently been shown 
to be entirely specific; in the communication cited 
details are given of a process by means of which a 
rapid and accurate method of estimation is afforded 
of a substance the analytical detesmination of which 
has always presented some difficulty and uncertainty. 
DurINnG the past few years several active principles 
have been isolated from ergot which account for most 
of its peculiar physiological properties; certain other 
effects have, however, been observed which have not 
been satisfactorily explained hitherto. In the current 
number of the Biochemical Journal (vol. viii., No. 1) 
Mr. Arthur J. Ewins describes the isolation from 
ergot of traces of acetylcholine, a base which pro- 
duces a peculiar inhibitor effect on the heart, suggest- 
ing that caused by muscarine, which had been fre- 
quently observed to characterise the use of ergot. 
That this base is responsible for the effect was shown 
not merely by its actual isolation from ergot, but by 
the fact that the synthetic base, prepared from choline, 
has an identical physiological action. 
Tue following books relating to science are 
announced by Gebrtider Borntraeger, of Berlin :— 
“Die wichtigsten Lagerstatten der ‘ Nicht-Erze,’”’ 
Prof. O. Stutzer, Teil. ii., Kohle, Allgemeine Kohlen- 
geologie, illustrated; ‘‘ Ueber die Bedingungen der 
Gebirgsbildung,”’ Dr. K. Andrée, _ illustrated; 
‘‘Beitrage zur chemischen Petrographie,” Prof. A. 
Osann, Dritter Teil; ‘‘Geologischer Fuhrer durch 
Nordwest-Sachsen,” Dr. E. Krenkel, illustrated; 
“Praktikum der chemischen, biologischen und _ bak- 
teriologischen Wasseruntersuchung,”’ Prof. O, Emmer- 
ling, illustrated; ‘‘Geologische Charakterbilder,” 
edited by Prof. H. Stille, illustrated, Heft 18, 19, 20. 
Tue following new books are announced by C. Griffin 
and Co., Ltd.—In Biology.—Practical Field Botany, 
A. R. Horwood, illustrated; in Chemistry—A Text- 
Book of Inorganic Chemistry, edited by Dr. J. Newton 
Friend, in nine volumes; Elementary Practical Chem- 
istry, for Medical and other Students, J. E. Myers 
and J. B. Firth; The Storage of Petroleum Spirit, 
Major A. Cooper-Key; The Petroleum Technologist’s 
Pocket Book, Sir Boverton Redwood and A. East- 
lake, illustrated; Oil Chemists’ Pocket-Book, Dr. H. 
Ingle and J. A. Sutcliffe; The Raw Materials of the 
NO 231 75 ny OL. ..03 | 
J. Griinwald, translated by Dr. H. H. Hodgson; in 
Engineering—An Introduction to Town Planning, J. 
Julian, illustrated; in Geology—A Text-Book of Geo- 
logy, Prof. J. Park; in Medical Science—A Practical 
Handbook of the Tropical Diseases of Asia and 
Africa, Dr. H. C. Lambart, illustrated; in Metallurgy 
| —The Metallurgy of the Non-Ferrous Metals, Prof. 
W. Gowland, illustrated; Practical Assaying, Prof. J. 
Park, illustrated; in Technology—Clay and Pottery 
' Industries, being vol. i. of the Collected Papers from 
the County Pottery Laboratory, Staffordshire, by 
several authors, edited by Dr. J. W. Mellor, illus- 
trated; in Miscellaneous—Roberts-Austen : Addresses 
and Scientific Papers, together with a Record of the 
Work of Sir William Chandler Roberts-Austen, 
K.C.B., F.R.S., compiled and edited by S. W. Smith, 
illustrated; Memorials of Henry Forbes Julian, com- 
piled and edited by his wife, Hester Julian, illus- 
trated. 
OUR ASTRONOMICAL COLUMN. 
THe ForrHcoMING TotaL SoLtar Ecviirse.—While 
the various official and private expeditions are making 
preparations for observing the total solar eclipse of 
August 21 next, steamship companies are offering 
enticing pleasure cruises which include a brief stay on 
the line of totality on the Norwegian coast. As the 
| last total solar eclipse visible in England took place 
so far back as the year 1724, and as 1927, the time 
for the next one, is as yet some time off, the oppor- 
tunity to view the eclipse of this year should not be 
lost. The Royal Mail Steam Packet Company’s ocean 
yachting steamer, Arcadian, twin screw, and 8939 
gross tonnage, is timed to leave Grimsby on August 
15 and Leith August 16, and will take up a position 
near Alsten, north cf Torghatten Island, well on the 
central line. The Norway Travel Bureau of the Great 
Northern Railway Company has also arranged a special 
cruise. Passengers leave Newcastle-on-Tyne by the ss. 
Venus on August 15, and join the special steamer Mira 
at Bergen on August 17, a position being taken up at 
Stokka on eclipse day. It is stated that if a party 
of seventy-five to eighty members of the Royal Astro- 
nomical Society and the British Astronomical Associa- 
tion would avail themselves of this facility no other 
passengers would be accepted, and the itinerary would 
be varied to meet the requirements of the party, and 
the stay at any place in the eclipse zone prolonged. 
A Monturiy Report oN Mars.—Prof. W. H. Picker- 
ing has commenced the publication of a series of 
monthly reports on the appearance of the planet Mars. 
The first of these was printed in the January number 
of Popular Astronomy (vol. xxii., No. 1, 1914). The 
observations described are made at the Jamaica Astro- 
nomical Station of Harvard College Observatory, 
situated near Mandeville, at an altitude of 2100 ft., 
The instrument employed is an 11-in. Clark refractor, 
and the magnification generally used 660. Prof. 
Pickering states that the changes on Mars cannot be 
described as conspicuous except when the planet is 
viewed under very exceptional conditions, but in their 
general character they may be detected by careful 
study, even by those who are not fortunate enough to 
reside in those portions of the world where the seeing 
is habitually good. It is in order to emphasise this 
constant change, unlike changes seen on Jupiter, but 
resembling more those which occur on our earth, that 
Prof. Pickering proposed the issue of this monthly 
