496 
NATURE 
[Marcu 24, 1904 
WE have received a copy of the first issue—that for 1903 
—of Mimir, which is wholly concerned with Iceland and 
Icelandic institutions. Tne annual publication is intended 
to help Icelandic research, to keep the people of Iceland and 
the foreign student informed of the progress of this re- | 
search, and to promote the proper development of the island 
and its people. Among the interesting contents we notice 
the account of institutions in Iceland, the addresses of 
foreign students of Old-Northern letters, and numerous notes 
on Icelandic matters Mimir is 
printed in English, and is published by Martius Truelsen, 
of Copenhagen. 
of general interest. 
Tue tables relating to the output of coal and other 
minerals and the number of persons employed at mines 
worked under the Coal and Metalliferous Mines Regulation 
Acts during the year 1903 have now been printed. The 
tables have been prepared by direction of the Home Secretary 
from returns furnished by H.M. Inspectors of Mines; and 
they form part of the general report and statistics for 1903 
of mines and quarries. The output of coal from mines 
under the Coal Mines Regulation Act, which was 227,084,871 
tons in 1902, Was 230,323,391 
crease of 3,238,520 tons. 
in 1903, showing an in- 
The number of persons employed 
at these mines in 1903 was 842,066, an increase of 17,275. 
Two new general methods of preparing aldehydes are | 
given in the current number of the Comptes rendus. The 
first of these, by M. E. E. Blaise, consists in the conversion 
of the acid through its bromine derivative into the corre- 
sponding a-hydroxy-acid, which by the action of heat is first 
converted into a lactide, and this on distillation splits up 
into carbon monoxide and the aldehyde of the next lower 
acid. The yields are very good, from 50 to 60 per cent. 
of the acid employed, and from the results obtained would 
appear to be generally applicable to the higher fatty acids. 
The second method, published by M. F. Bodroux, is based 
upon the action of magnesium alkyl compounds in toluene 
solution upon ethyl orthoformate. Here again the reaction 
gives good yields—from 55 to 75 per cent. cf the theoretical 
—and the examples given by the author include members of 
both the fatty and aromatic series. 
Tne Geneva Archives des Sciences for January contain 
an important article on the theory of nickel steels, by M. 
Guillaume, of the des Poids et 
One of the most important properties of these 
alloys is their low coefficient of expansion, which becomes 
zero at about 36 per cent. of nickel. It is pointed out that 
the conversion, below 890° C., of the hard, non-magnetic 
y Variety of iron into soft, magnetic a iron is accompanied 
by an expansion of 3 mm. in a rod a metre long. The 
addition of nickel lowers the transition temperature until in 
Bureau international 
Mesures. 
presence of 20 per cent. of nickel magnetic properties only 
appear when the alloy has been cooled below 200°, whilst 
(owing to a kind of the magnetic 
properties do not disappear again until the alloy has been 
‘heated to 600° C. In the non-expansive alloys the transition 
temperature appears to have been brought down to atmo- 
spheric temperatures, the constancy of length is 
cattributed to the same change in structure as that which 
causes the abrupt expansion in pure iron when cooled below 
Sgo0°. A striking proof of the correctness of this view was 
obtained. by cooling a metre rod in liquid air, when it 
suffered a permanent expansion of 3-9 mm., and sub- 
sequently showed the high coefficient of expansion character- 
thermal hysteresis) 
and 
istic of @ iron in place of the lower coefficient characteristic 
pf y iron. 
NU. 1795, VOL. 69] 
Tue additions to the Zoological Society’s Gardens during 
the past week include a Green Monkey (Cercopithecus 
callitrichus) from West Africa, presented by Mrs. L. A. 
Moline; a Vervet Monkey (Cercopithecus lalandti) from 
South Africa, presented by Captain Campbell; two Eastern 
Sarus Cranes (Grus antigone) from Northern India, pre- 
sented by Lieut.-Colonel H. H. Smyth; a Greater Sulphur- 
crested Cockatoo (Cacatua galerita) from Australia, pre- 
sented by Mr. C. Hammett; a Hybrid Pheasant (between 
Phasianus reevesi and Euplocamus nycthemerus), presented 
by the Earl of Ducie; two Ring-tailed Lemurs (Lemur 
catta) from Madagascar, an Azara’s Opossum (Didelphys 
asaroe) from South a Blue-necked Cassowary 
(Casuarius intensus) from New Guinea, four Dusky 
Francolins (Pternistes infuscatus), two Jackson’s Francolins 
(Francolinus jacksoni), two Schueth’s Francolins (Franco- 
linus schuethi) from East Africa, two Hybrid Parrakeets 
(between Platycercus semitorquatus and P. barnardi) from 
Australia, deposited. In last 
(p 473), Snow Leopard presented by Major Cox should 
read Major Mackintosh. 
America, 
additions in week's issue 
OUR ASTRONOMICAL COLUMN. 
Variations OF THE Martian Canarts.—During the 
1903 opposition of Mars, Mr. Lowell observed changes in 
the canals which he believes were the results of artificial 
interference. Among the canals mapped by Schiaparelli in 
1877 were three, situated on the eastern edge of the Syrtis 
Major, which met at a common point, the Lacus Tritonis, 
and which he named Thoth, Triton and Nepenthes re- 
spectively. In 1882 and 1884 Thoth appeared double, but 
was undoubtedly seen, and in 1884 Nepenthes was also dis- 
tinctly double. 
At the commencement of Mr. Lowell’s observations in 
1894 he was surprised to find no trace of these three canals, 
or of the Lacus Moeris, a widening of Nepenthes, although 
other well known but smaller features were plainly visible. 
Instead of Thoth another canal, which he named Amenthes, 
appeared, running from Syrtis Minor to the Aqua Calidz, 
nearly parallel to the earlier recorded directions of Thoth 
and Triton. During the oppositions of 1896-7 and 1901 
this continued as an easily seen object, and Mr. Lowell 
concluded that it was really Thoth which had been wrongly 
placed on the earlier drawings. During February and 
March, 1903, Amenthes was still visible but less distinct, 
and on April 19 it was accompanied by Thoth in exactly the 
position shown on Schiaparelli’s earlier map; on April 20 
Thoth alone was visible. Suddenly, on May 29, the Lacus 
Moeris, which had long been given up, appeared and_ be- 
came a noticeable feature of that region of the planet’s 
surface. In July Amenthes reappeared alongside Thoth and 
Triton, and thus settled the question of the presence of two 
canals. 
These changes are entirely independent of the seasonal 
changes, and whilst the two ‘ visibility ’’ curves of Thoth 
and Amenthes vary inversely, the curve derived from the 
summation of them agrees very closely with that of a 
‘“ mean ”’ canal, for which only the seasonal changes have 
as yet been observed. 
From these phenomena Mr. Lowell reasons that owing 
to the small amount of water on Mars it becomes necessary 
to irrigate the surface in sections, and for this purpose the 
canals are artificially regulated, Thoth and Amenthes being 
allowed to fill up and irrigate the regions surrounding them 
alternately (Lowell Observatory Bulletin, No. 8). 
Pror. BurRNHAM’S MEAsuRES OF Dous_e StTars.—One of 
the Decennial Publications (vol. viii.) of the Chicago Uni- 
versity is devoted to a record of the measures of double 
stars made by Prof. S. W. Burnham with the Yerkes 
yo-inch refractor during 1900 and 1901. The systems 
which have been measured are those which have been long 
neglected and are little known, and those which, from the 
few early measures or the uncertainty of their results. could 
not be classified as to their motion or otherwise. Most of 
the pairs were selected from the Herschel and South cata- 
