670 
NATURE 
[AuGUST 29, 1912 
In the meantime, Dr. Hertzsprung announced a 
variation of about 0°15 mag., determined from photo- 
graphs; so Mr. Stebbins again took up the observa- 
tion of Polaris, using 8 Ursz Minoris as the com- 
parison star. This is some 17° away, and, as the 
correction for differential absorption becomes too great 
if the altitudes are not nearly the same, the time of 
observation was unusually restricted. However, Mr. 
Stebbins secured measures on seventeen nights be- 
tween March 4, 1911, and April 8, 1912, and from 
these he finds a variation of o’078 mag., thus fully 
confirming Hertzsprung’s result, for the two light- 
curves are practically in the same phase. The differ- 
ence in amplitude is probably explained by the fact 
that Hertzsprung employed the actinic rays, whereas 
the selenium photometer utilises those on the red side 
of the visual region, and variables of this type 
(Cepheid) usually show greater variations photo- 
graphically than they do visually. 
A photographic comparison made at Harvard last 
year by Mr. King showed a variation of about 
oro mag. 
The comparison star, 8 Ursz Minoris, used by Mr. 
Stebbins, has been described as a variable, but the 
results give no indication of change while it was 
under observation during this research. 
Tue Sovar Eciipse oF ApriL 17.—Tlwo interesting 
papers dealing with the solar eclipse of April last are 
published as abstracts from the Astronomische 
Nachrichten by Prof. Schorr and Dr. Graff. 
In the former, Prof. Schorr describes the observa- 
tions made at the Hamburg Observatory, and repro- 
duces a number of the excellent photographs taken by 
the various instruments. In the latter, Dr. Graff 
describes in detail the profile of the moon’s limb at the 
time of mid-eclipse. He tabulates the elevations and 
depressions for every 2° of the limb, and then shows 
them, exaggerated ten times, on a drawing. They 
are also shown and named on a set of altitude curves 
covering the entire limb. The important part played 
by the lunar profile during this eclipse gives an added 
interest and importance to these deductions. 
y GEMINORUM A SPECTROSCOPIC Binary OF EXCEP- 
TIONALLY Lone PEeriop.—From observations made at 
the Ottawa Observatory, combined with earlier ob- 
servations made at other observatories, Mr. Harper 
has deduced elements for the orbit of the spectroscopic 
binary y Geminorum. The period comes out at about 
2175 days (nearly six years), so that the star is unique 
among binaries discovered spectroscopically in having 
so long a period. Betelgeuse, a star of a very much 
later type, possibly has a similar period, but defini- 
tive elements have not yet been derived for its orbit. 
The spectrum of y Geminorum is of the Sirian type, 
and the periods for other spectroscopic binaries of this 
type range from a fraction of a day up to too days, 
so that the star may be looked upon as bridging the 
gulf between the periods of the longest spectroscopic 
and the shortest visual binary. (The Journal of the 
R.A.S. Canada, vol. vi., No. 3.) 
Tue HampurGc OpseRvATORY.—With the reports for 
1gto0 and ig1t of the work done at the Hamburg 
Observatory, Prof. Schorr issues a most interesting 
brochure containing photographs of the new buildings 
and instruments at Bergedorf, where the work of the 
observatory is now carried on. Among the instru- 
ments now erected is a large refractor, a 73-in. 
meridian circle, and a reflector of 4o in. aperture 
and ro ft. focal length; but, according to the 1911 
report, the objective of the refractor is still un- 
mounted. The reports show that observations of 
comets and planets, the time-service for various ports, 
and a new reduction of the Hamburg star catalogue 
are occupying the attention of the staff. 
NO. 2235, VOL. 89| 
| published in rog11. 
REGIONAL GEOLOGY IN EUROPE. 
J. SEDERHOLM’S summary of the prequater- 
* nary rocks of Fennoscandia, with its admirable 
coloured geological map of Norway, Sweden, and 
Finland, is now issued in French as Bulletin 24 of the 
Commission géologique de Finlande. Under the 
director’s active guidance, six further bulletins were 
V. Tanner has drawn a number 
of interesting conclusions from his discovery of 
brachiopods, resembling Kutorgina or Acrotreta, in 
| dyke-like masses of sandstone filling cracks in granite 
in the Aland Islands, at the entry to the Gulf of 
Finland (Bull. 25, p. 10). These fossils are probably 
of Lower Cambrian age, and the cracks were opened, 
| perhaps through earthquake action, in a surface of 
pre-Cambrian rocks which had been already worn 
down to a peneplane. It is urged that the present 
Fennoscandian peneplane, which includes the surface 
of the islands, represents only a small further degra- 
dation of that which was formed towards the close of 
pre-Cambrian times. 
Bulletins 27 to 30 are extracted from the Atlas of 
Finland, published in 1910, and form an illustrated 
summary of the surface-forms and geology of the 
country, drawn up by the director. No. 27, ‘* Esquisse 
| hypsométrique de la Finlande,” includes a new con- 
' toured map in colours, which shows how large a 
part of the country lies below 300 metres. The con- 
tours, though the scale of the map is 1 : 2,000,000, 
even bring out some of the eskers, such as the fine 
ridge of Kangasala on the road from Tavastehus to 
Tammerfors. A geological map on the same scale 
accompanies No. 28, on ‘‘Les roches préquaternaires 
de la Finlande,” and the extent to which the country 
is covered by glacial deposits is shown by that in 
No. 29, on ‘‘Les dépéts quaternaires.’”’ Here the 
eskers, and the huge terminal moraines from Hangé 
to Joensuu, some 600 kilometres in length, stand out 
prominently in red, and show the form of the great 
ice-lobe and the course of its subglacial waters at the 
epoch when stagnation set in. In common with many 
Scandinavian geologists, Sederholm pictures the eskers 
, as formed in the late glacial sea as the ice shrank 
back, the south-eastern end of each being thus older 
than that towards the Gulf of Bothnia. The sandy 
marginal moraines, running across the course of the 
ice-movement, are described as ‘‘oses marginales.”’ 
The words ‘‘ose’’ and ‘‘oses”” have been adopted for 
the more difficult ds and asar in Fennoscandian litera- 
ture, whether written in French or English (p. 6). 
Bulletin 30 takes a still wider field, and deals with 
“La géologie quaternaire et la géomorphologie de la 
Fennoscandia.”” The coloured maps show the exten- 
sion of the Scandinavian ice-sheets, the isobases in- 
dicated by the present positions of raised beaches, 
and the lines of fracture traceable in the prequaternary 
relief. The block-structure of so much of the Fenno- 
scandian surface, and notably of the Finnish low- 
land, is referred to fracturing and faulting during 
the Alpine epoch of unrest. The scarps along the 
sides of fjords or rivers are held to be more often 
due to earth-movement than to ordinary erosion, 
though eroding agents have, of course, acted along 
the lines of weakness thus produced. As we write, 
we recall a granite cliff on the farm of Eskola by 
the Kyminjoki, and Wilhelm Ramsay’s exposition of 
it as we sat upon the grass above the river. The 
gift of these excellent summaries to geologists is a 
further reminder of the hospitality of Fennoscandian 
lands. 
Visitors to Norway will profit by the description of 
| the Bergen district by C. F. Kolderup and H. W. 
Monckton, written in connection with the excursion 
of the Geologists’ Association in 1911 (Proc. Geol. 
