January 25, 19 12] 



NATURE 



415 



GROWTH AND SHRINKAGE OF GLACIERS.'' 

 ^pHE volume referred to below deals with certain 

 J^ glaciers in Savoy ; four of them in the massif 

 of Mont Blanc, the same number in the Maurienne, 

 and one in the Tarentaise. It is well known that, 



Fig. I. — Glacier d\i Tour, October, 1891. 



luring the last few centuries, the Alpine glaciers have 

 3een increasing and decreasing in volume, though the 

 jxtent and duration of these oscillations have been 

 .ess certain, and observers in different parts of the 

 ;hain are now watching and recording the amount 

 3f changes. The glaciers near 

 Dhamonix are particularly well 

 idapted for study, because that place 

 las been frequented by travellers 

 'or a longer time than other Alpine 

 rentres. Hence more information 

 ;an be obtained, and this in some 

 ■ases is supplemented by drawings, 



Ivhich, however open to criticism as 

 vorks of art, are valuable records of 

 acts. 



These Savoy glaciers attained one 

 naximum, according to a curious 

 ontemporary record, in 1643 ; they 

 lad greatly dwindled in 1770, but 

 luring the next ten years they again 

 ncreased. Early in the next 

 entury came another advance, 

 /hich culminated in 1819, and was 

 ollowed by another retreat. They 

 ^ain advanced in 1826, and oscil- 

 ited considerably during the next 

 Un years. In tKe latter part of this 



I "entury the Chamonix glaciers 

 pparently did not diminish so much 

 s those in most other parts of the 

 Jps ; for fhey are said to have 

 eased shrinking in 1875, and to 

 i^ave reached another maximum 

 though smaller than on some previous occasions) in 

 I892. 

 I The French surveyors have worked on a definite 



,* " Ktudes GlacioloRiquM en Savoie." Tome ii. (Minislere de rAjfricul- 

 ire. Direction <Je I'Hydrauliqtie et des Ameliorations Agricoles. j.Service 

 » Grandes Forces hydrauliqties, Rdgion des Alpes.) Pp. vii + 140 + 19 

 -f-^. (191C.) 



and comprehensive plan, making maps, fixing points 

 for measurement and observation, and taking photo- 

 graphs, so that a precise register, from year to year, 

 can be kept of the changes in these ice-streams. Some 

 old illustrations have been reproduced, which, though 

 artists might justly criticise, give us 

 a good notion of the state of certain 

 glaciers about the maximum of 

 1832, and photographs show some of 

 the changes during the last twenty 

 years. Those, for instance, of the 

 Glacier du Tour in 189 1 and 

 1898 (Figs. I and 2) indicate 

 a considerable alteration in the 

 volume of the ice; for an ice 

 fall has shrunk enough to disclose 

 a large part of the cliff by which it 

 has been produced, while a third 

 view, taken in 1907, exhibits a still 

 larger amount of bare rock. It is 

 also worth observing, though we 

 must not enlarge upon so contro- 

 v-ersial a subject, that these illustra- 

 tions have a bearing on the question 

 of the erosive power of ice. They 

 indicate (and this is corroborated in 

 other parts of the Alps) that a 

 glacier in passing over a well- 

 marked step of rock often neither 

 smooths it away nor digs for itself 

 anything like a deep channel. 



The position of the glaciers 

 treated in this work has been, so 

 far as possible, ascertained and recorded, the method 

 of studying them being described and worked out in 

 a typical case, so that students of glaciology 

 receive a valuable addition to the facts at 

 their command, and their successors, in another 



NO. 2204, VOL. 88] 



Fici. J. — ijlacier du Tour, October, 1893. 



half-century, will be in a far better position to ascer- 

 tain the precise causes of these ebbs and flows in 

 the ice-streams of the Alps. A sentence on the title- 

 page of this book is significant, " Service des grandes 

 Forces hydrauliqucs," for it shows that the French 

 Government (the work is undertaken by the Minis- 

 terial Department of Agriculture) recognises the value 



