188 1] 
Dec. 22, 
NATURE 
185 
study of what is going on now in Arctic countries, this relation 
has been rather neglected. In a second paper, which has just 
appeared in the November number of the Archives, M. Forel 
discusses the influence of ablation on the thickness of a glacier, 
the ablation, together with the amount of snow fallen on the 
surface of the zevé, being the two chief causes of changes in 
thickness, Our knowledge of the influence of ablation is almost 
nothing ; but the influence due to an increase, or decrease, of 
the feeding of a glacier being felt, and exaggerated, throughout 
the whole length of a glacier, while the ablation has aa impor- 
tance only in its lower parts, M. Forel concludes that this second 
cause never would have the importance of the first. In any 
case both causes never can be simultaneous, the zevé taking fifty 
or a hundred years to reach the low end of the glacier; thus the 
thickness of a glacier at this end depends upon the quantity of 
snow fallen on the zevé some fifty or a hundred years ago, and 
on the ablation during a few recent years, which causes may be 
either concurrent, or opposing, in increasing or decreasing the 
thickness. He remarks also that altozether it seems that the 
retreat of glaciers, which reached its maximum about the year 
1875, was not a local phenomenon, but was simultaneously ob- 
served in the Austrian Alps, in the Pyrenees, in the Caucasus, 
in Scandinavia, and in Greenland, M. Forel concludes by ask- 
ing the naturalists of all countries to indicate the advance and 
retreat of glaciers as much as possible in figures, and to measure 
the thickness of glaciers at several well-determined parts. 
WE fear all hope must be given up as to the safety of Mr. 
Powell in the Sa/adin balloon. A balloon was seen on the night 
of the 16th, going by Santander and Bilbao towards the sea, but 
nothing more has been heard of it. It may have been the Sa/a- 
din, but if so, and Mr, Powell had been in it and conscious, he 
would certainly have made some sign. Mr. Powell was an ardent 
and intelligent aéronaut, and his death, which we fear is only too 
certain, must be regarded as a loss to science in the pursuit of 
scientific knowledge. 
THE Royal Italian Scientific Institution at Venice offers a 
number of prizes for various memoirs. Among them we note 
the following two as of more general interest :—(1) ‘‘ A State- 
ment of the Hypotheses recently advanced by Physicists on the 
Causes of the Phenomena of Light, Heat, Electricity, and 
Magnetism” (prize 3000 lire (about 110/.), term March 31, 
1883). (2) ‘‘A Systematical and Critical Enumeration of the 
Cryptogamic Plants hitherto observed in the Venetian Pro- 
vinces ” (prize and term for this treatise are not yet fixed). 
THE death is announced, on November 29 last, of Dr. Wil- 
helm Weith, Professor of Chemistry at Ziirich University. He 
died in the Island of Corsica,:; where he was staying on a visit, 
at the early age of thirty-seven years. 
In the night of November 19-20 the tunnel through the Col 
di Tenda, on the frontier between France and Piemont, was 
broken through. Cuneo is the nearest place on the Italian side 
of the mountain, where the Italian railways will join the new 
French branch extending through the tunnel. 
WE have on our table the following books :—Cultivation of 
Liberian Coffee, by H. A. A. Nicholls (Silver and Co.); 
Keport of the Scientific Results of H.M.S. Challenger, 1873-76, 
Vol. iii. Zoology; Koumiss, by G. L. Carrick (Blackwood) ; 
Every-day Life in Our Public Schools, edited by C. E. Pascoe 
(Griffith and Farran) ; Statistical Atlas, Parts x. and xi., by C. P. 
Bevan (W. and: A, K, Johnston) ; Perfect Way in Diet, by Anna 
Kingford (Kegan Paul) ; Educational Theories, by Oscar Brown- 
ing (Kegan Paul) ; The Bedfordian System of Astronomy, by J, 
Bedford (H. Vickers) ; Description of the Chemical Laboratory 
at the Owens College, Manchester, by Prof. H. E. Roscoe, 
F.R.S. (Cornish) ; Ideality in the Physical Sciences, by B. 
Peirce (Little, Brown and Co.); European Ferns, by James 
Britten (Cassell, Petter, and Galpin); The Encyclopzedic Dic. 
tionary, by Robert Hunter (Cassell, Petter and Galpin); John 
Amos Comenius, by S. S. Laurie (Kegan Paul); Elementary 
Treatise on Electricity, by Prof. Clerk M axwell (Clarendon 
Press) ; Astral Origin of the Emblems and Hebrew Alphabet, 
Rey. J. H. Broome (Stanford) ; Encyclopedia Brittannica, vol. 
xiii. (A. and C. Black) ; Old Greek Education, by J. P. Mahaffy 
(Kegan Paul); Practical Chemistry, by Howard (William Col- 
lins) ; British Almanack and Companion (Stationers Company). 
Tue following recently-published Norwegian and Danish 
pooks may interest some of our readers:—‘‘ A Geological De- 
scription of the Lofoten and Vesteraalen Districts of Norway,” 
by K, Pettersen, with maps, and with interesting remarks on 
the coal-bearing Jura formation of those provinces; ‘* A Flora 
of Iceland,” by M. Chr. Gronlund, being the results of his visits 
to Iceland during the years 1868 and 1876, from which he has 
brought back very rich collections of plants; the flora of Ice- 
land includes, according to M. Grénlund, 870 species, of which 
332 are Phanerogams, the total number having to be increased 
by many Alge; ‘From Fields and Forests: Pictures of the 
Life of Insects,” in two volumes, by M. v. Bergsoe; and a 
pamphlet, by M. R. Lehmann, on the former coast-lines in 
Norway. 
S. A. Lex, who steadily pursues his studies on the recent 
geology of Norway, contributes to the last number of the Nor- 
wegian Archiv for mathematics and natural science, a paper on 
the upheaval of Norway, and its coast-lines and terraces. 
ADVICES received at Plymouth give some particulars of a 
destructive typhoon which visited Haiphong and Tallee on 
October 8, causing great destruction and loss of life. The wind 
blew with tremendous violence, and the heavy sea flooded the 
whole of the surrounding country. In Tallee there were six feet 
of water in the houses three and four miles distant from the sea- 
shore. ‘The current was so strong that it swept away the entire 
town, the number of persons drowned being estimated at over 
3000. 
In the December number of the serial 4uf der Hohe, Prof. 
Palmieri, the Director of the Observatory on Mount Vesuvius, 
communicates a discovery with regard to volcanoes. Ina series 
of spectro-analytical examinations of the lava Prof. Palmieri 
has, it is stated, just discovered a new line which corresponds 
exactly with that of helium, the famous element hitherto seen 
in the solar spectrum only, 
THE displacement of zso¢ierms (or lines drawn through places 
having an equal mean temperature), with the season, has some 
interesting practical bearings. Several years’ recent (so-called) 
phenological observation in Sweden proves that in general each 
phenomenon of plant-life occurs only at a certain temperature. 
A similar rule applies to the arrival of many birds of passage. 
Comparing the times such phenomena take to advance one 
degree of latitude, it is found on the Baltic coast that their 
greatest velocity is in midsummer. The numbers of days for an 
advance of one degree are in sundry cases as follows :—Freeing 
of lakes from ice 6°0, flowering of April plants in Southern 
Sweden 4°3, of May plants 2°3, of June plants 1°5, of July 
plants 0°5, appearance of leaves (general average) 2°3, ripening 
of fruit 1°5, fall of leaves 2°3, freezing of lakes 5*1. A recent 
study by Herr Hildebrand (of Upsala) of the movement of 
isotherms in the north of Europe throws light on these facts, 
showing (among other things) that while in Sweden the rate of 
the movement increases with the temperature, in Russia it 
remains nearly constant. The author gives a number of maps 
for various temperatures. Taking o° it is found that the iso- 
therms running nearly north and south moye eastwards, but in 
