JANuaRY 28, 1904] 
NATURE 
of the unsoftened and softened waters are given which 
jpermit of a fair comparison being made as to the suitability 
of the various types for special purposes. Of the seventeen 
softeners, fourteen are fitted with filters, two of them having 
sand filters, and the others woodwool, or sponge filters. 
WE have received vol. ii. of the Transactions of the North 
Staffordshire Ceramic Society. The Society has a member- 
ship of thirty, and seven papers have been read before the 
members during the session. Of special interest is a paper 
by Messrs. Hopwood and Jackson on the nature and origin 
of the abnormal red, blue and black colorations of fire-clay 
ware. The red colorations are found to be due to the con- 
wersion of the iron in the clay substance into free ferric 
oxide, the black principally to free carbon, whilst the 
external vitreous blue films of blue-fired clay-wares are 
found to consist of a basic ferrous silicate. 
Tne much debated question regarding the dual nature 
of chromium solutions as manifested in the green and violet 
colour is again discussed by Messrs. Richards and Bonnet 
in a recent number of the Proceedings of the American 
Academy. The authors’ experiments and previous observ- 
ations seem to be most easily explainable on the assumption 
that the violet solutions of, say, chromium sulphate contain 
the salt in a state comparable to that of other normal salts, 
whilst the green solutions are due to hydrolysis resulting 
in the production of free acid and one or more complex 
basic salts. 
IN the quarterly statement of the Palestine Exploration 
Fund Mr. W. Ackroyd discusses the cause of the saltness 
of the Dead Sea. Facts are brought forward which seem 
to indicate that the saltness cannot be entirely due to 
accumulation of chlorides derived from the Palestine rocks 
‘by solvent denudation or the cutting off of an arm of the 
Red Sea by the rising of Palestine in past ages followed by 
evaporation of the solution. The author brings evidence 
forward in favour of a third cause, which is perhaps more 
important than either, viz. the atmospheric transportation 
of salt from the Mediterranean. 
A THIRD revised edition of part ii. of “‘ Machine Design,”’ 
by Prof. Forrest R. Jones, of Cornell University, has been 
published in this country by Messrs. Chapman and Hall. 
This part of the work deals with the form, strength, and 
proportions of parts, and the new issue has been increased 
by about eighty pages of new matter. 
THE additions to the Zoological Society’s Gardens during 
the past week include a Vervet Monkey (Cercopithecus 
Jalandii) from South Africa, presented by Mrs. Hughes; 
a White-collared Mangabey (Cercocebus collaris) from West 
Africa, presented by Mr. H. Ion; a Chacma Baboon (Papio 
porcarius) from South Africa, presented by Mr. James 
Adams; a Levaillant’s Cynictis (Cynictis pentcillata) from 
South Africa, presented by Lady Constance Ryder ; a Spotted 
Ichneumon (Herpestes nigropunctatus) from Nepal, pre- 
sented by Mr. S. D. Pritchard; two Herring Gulls (Larus 
argentatus), European, presented by Mr. F. H. Haines; 
a Barn Owl (Strix flammea), British, presented by Master 
C. Fox; a — Sheep (Ovis sp. inc) from Baluchistan, two 
Waxwings (Ampelis garrulus), European; a Grey Squirrel 
{Sciurus cinereus) from North America, a _ Brazilian 
Tortoise (Testudo tabulata) from South America, two 
Ceylonese Terrapins (Nicoria trijuga) from India, two 
Derbian Sternotheres (Sternothoerus derbianus) from West 
Africa, deposited; a Humboldt’s Lagothrix (Lagothrix 
humboldti), a Red-faced Ouakari (Ouacaria rubicunda) 
Trem the Upper Amazons, purchased. 
NO. 1787, VOL. 69 | 
OUR ASTRONOMICAL COLUMN. 
ASTRONOMICAL OCCURRENCES IN FEBRUARY :— 
Feb. 1. 12h. Saturn in conjunction with the sun. 
4. 8h. 41m. Minimum of Algol (8 Perse). 
7. 5h. 30m. ” ” ” 
8. 6h. 17m. Transit (ingress) of Jupiter’s Sat. IV. 
(Callisto). 
9. 15h. Ceres in conjunction with moon. Ceres 
o 8’ N. 
», 2th, Mercury at greatest elongation. 25° 52’ W. 
12. 16h. Venusin conjunction with moon. @ 4°8'S. 
14. Venus. Illuminated portion of disc =0°797. 
24. 5h. 57m. to 7h. 15m. Moon occults «@ Tauri 
(Aldebaran, Mag. 1'r1). 
25. 17h. Mercury in conjunction with Saturn. 
o 49'S. 
», 17h. Mars in conjunction with jupiter. 
N. 
27. 7h. 13m. Minimum of Algol (8 Persei). 
29. Sh. 53m. to gh. 46m. Moon occults o Leonis 
(mag. 3°8). 
VARIABILITY OF THE Minor PLanet Iris.—A telegram 
from Prof. Pickering, through the Kiel Centralstelle, 
announces that Prof. Wendell has discovered a_ periodic 
variability in the brightness of the minor planet (7) Iris. 
The period of the changes is six hours, and the range of 
variability about one-quarter of a magnitude. 
Harvarp MeripiaN PHOTOMETER OBSERVATIONS.—Part i. 
vol. xlvi. of the Harvard College Observatory Annals con- 
tains the tabulated results of the meridian photometer 
observations made by Prof. Solon. I. Bailey at Arequipa 
and Cambridge (Mass.) during the years 1899-1902. 
Chapter i. contains the reduced observations of some 4500 
stars situated south of —30° declination made at the 
southern station during 1899, the stars observed being 
generally selected from the Argentine General and Cordoba 
Zone Catalogues. 
One of the chapters contains the results of a series of 
observations made at Cambridge (1900-1902) in order to pro- 
duce a catalogue of standard stellar magnitudes for regions 
regularly distributed throughout the sky. To this end the 
sky was divided into 432 regions, each approximately 10° 
square, and one star of about the fifth magnitude was 
photometrically observed in each region, care being taken to 
select, wherever possible, a star having a first-type spectrum. 
All the stars were compared with A Ursa Minoris and other 
standard comparison stars, and on reducing the observations 
it Was soon apparent that the results obtained from A were 
systematically different from those obtained from the other 
stars. This difference indicates an increase of two-tenths 
of a magnitude in the brightness of A Ursa Minoris, which 
may either be due to a personal equation depending on the 
colour or to a real variation in the star. 
Licut CilaNGES OF € AuRIG2.—In Nos. 3918, 3919 and 
3920 of the Astronomische Nachrichten Herr H. Ludendorff 
publishes the results of an exhaustive research as to the 
most probable data for the light variation of e Aurige. 
He first gives and discusses the observational results of 
Argelander, Heis, Schwab, Plassman, and thirteen other 
observers, and then, applying suitable weights to the various 
results, obtains a mean result by the method of least 
squares. The resulting elements obtained from _ this 
analysis are 
Mercury 
Mars 0° 30’ 
2415476 days=April 1, 1901, 
07d. tm =313d., 
415840=March 31, 1902, 
where I =the epoch at which the light commences to 
decrease from its normal magnitude, t=the time taken for 
the complete decrease to minimum or the corresponding 
increase to maximum, t,=the duration of the constant 
minimum, and T,=the epoch of the mean minimum. 
Summarising the results the author finds that the star 
has a normal magnitude of 3-35, decreases 0-73 mag. in 
207 days, remains at constant minimum for 313 days, and 
then returns to the normal magnitude again in 207 days. 
After these changes it remains constant for 25-13 years. 
Thus the complete period for this star becomes 27-12 years, 
or ggo05 days, of which only 1-99 years are occupied by the 
actual variation. 
