EPISODE:
EARLY IDEAS IN NW EUROPE, 1790s, early 1800s
“We have here . . . many different hypotheses which may be produced by a single object” (de Luc, 1810, p.57)
Pierre Martel (1706-1767), a Swiss engineer, provided one of the earliest accounts of glaciers in the Alps, in the Chamonix area of the Arve valley. He noted the presence of "great Stones, which have been carried quite into the Valley of Chamouny" by the greater extension of the high glaciers in the past: "The Glacieres in the Ice Valley are not always in the same State, they sometimes augment, and sometimes diminish ; it is probable they have been more abundant ; by the marks which remain they, must have been, 80 feet higher [thicker] than they are now."
"The course of the l'Arve containing a map of the glaciers of Chamouny and the
highest mountains" (Martel, 1744)
View of looking south over the Arve River valley
In
1787, Bernhard Friedrich Kuhn (1725-1783) published a startlingly
"modern" account of glacial dynamics, foreshadowing work by Ignaz Venetz and
others by 30-40 years. He did not address the question of erratics and, in fact,
stated that "The fate of the regions surrounding the glaciers and the
alterations of their ice-masses during ancient times is entirely unknown to us"
possibly because "later revolutions in the earth's history would have completely
eradicated all signs of them everywhere" -- but he did document "deep grooves
which have been gouged out by the repeated friction of ice-masses as they push
past" and massive rocks that had been "broken up in to small pieces," however
unlikely one might think it possible that ice could do this. Kuhn also found
"unmistakable signs" of the expansion of glaciers in the Little Ice Age when "it
seemed as if Nature was stepping out of its normal course, and the glaciers
expanded rapidly," reaching their maximum size in 1600 AD. These "signs" were in
the form of "the moraines (Gandecken) or sand-walls of this period . . . which
indicate the expanse of the glaciers at that period." Kuhn also gave an account
of the manner in which glaciers move and of the snow and ice balance that
controls their fluctuations. He also provided an accurate account of the origin
of ice-bergs which hitherto had been thought to be sea-ice (and not glacier-ice
that had calved): "might not nature, after having formed ice on dry land, carry
it out to sea by processes, and under principles similar to those by which she
makes the glaciers of Switzerland move down the long valleys to the foot of the
Alps?"
Lower Grindelwald glacier in the early Nineteenth Century: one of the glaciers
Kuhn studied.
It is much retreated now. (http://users.unimi.it/glaciol/glaciologia/ghicon.html)
Horace-Benedict
de Saussure (1740-1799) among others, including Deodat de Dolomieu, Carl von
Linné (Linnaeus), and Peter Simon Pallas, addressed the puzzle of erratics. Some
erratics, such as the Pierre-a-Bot (Pierre Crapaud) near Neuchatel in the Alps,
were famous for their enormous size. The Pierre-a-Bot had apparently, somehow,
come down the Rhone Valley from a source in the Mont Blanc Massif to lie up on
the south-facing slope of the Jura Mountains near Neuchatel.
Saussure thought that water had transported the erratics. In a research "Agenda" (1796) Saussure addressed the issues of erratics and the sands and gravels that were widespread in Alpine valleys. Further work on their locations "may provide clues of direction, volume & strength of currents produced by the great revolutions of the Earth," and the "state of these rocks, [can give] an indication of the time elapsed since their arrival. " He wondered if they could "be viewed as a general phenomenon or whether it is a particular phenomenon, due to some local cause," and he speculated that "these blocks which occupy sites high on the mountains, were transported there by waves" and was it possibly a "huge tidal wave of possibly 800 toises [4,800 ft] in height for example, which would have transported these blocks on top of these mountains?" Saussure's figure of "800 toises" was apparently borrowed from Deodat de Dolomieu (1750-1801) who, in 1791-92, incorporated the idea that Earth had been the scene of several transient catastrophes into a general theory of the Earth.
Pierre-a-Bot (Pierre Crapaud –Toad Rock), outside Neuchatel, Switzerland
(for scale, note the bench seat)
(http://www.balades-en-famille.ch/show_pictures.php?photo=1110)
John
Playfair (1748–1819), in his "Illustrations of the Huttonian theory of the
Earth" (1802), argued in favor of the views of his late friend, the
philosopher-geologist James Hutton. Playfair was severely critical of theories
that invoked deluges for the transportation of drift and erratics in the Alps,
as well as for the formation of valleys and other landforms attributed to
deluges (p.377- 395; 395-406): he attributed erratics scrupulously to present
causes -- to a combination of more extensive glacial erosion and movement than
today (in the past when the Alps were higher), flash floods, and mass wasting –
all on a land surface that was more uniform and that was later eroded to its
present form. He
questioned the power of a flood to move these stones and wrote: “If the surface
is not supposed to have had a certain degree of uniformity in past times, a
debacle is insufficient for the transportation of stones: If it is supposed to
have had that uniformity, a debacle is unnecessary” (p.402).
Jean-Andre
de Luc (1727-1817) believed that the great boulders commonly found across
the North European Plain were local rocks from Earth's interior that had
been “thrown out by explosions of the interior expansible fluids” and scattered
them around (de Luc 1810, p.65, 181):
“The gravels and blocks of stone found scattered in such large quantities on the surface of our continents, nay, even those observed in the beds of rivers flowing in plains, were not deposited there by the operations of running waters . . . The gravels formed by the attrition of fragments of the strata, as well as the blocks of the same stones, were projected from the interior of the globe by the expansible fluids . . . and disseminated over the bottom of the sea by the agitation of the water” (de Luc 1809, p.345).
"Erratic" in Winterswijk, Netherlands
(http://www.panoramio.com/photo/9243770)
QUESTIONS:
FURTHER READING
De Luc, J.A. (trans. H. de la Fite) 1809 An elementary treatise on geology: determining fundamental points in that science, and containing an examination of some modern geological systems, and particularly the Huttonian theory of the earth. London, F.C.&J. Rivington http://books.google.com/books?id=Cw4AAAAAQAAJ&pg=PR1
De Luc, J.A. 1810 Geological travels London, F.C.&J. Rivington http://www.google.com/books?id=se44AAAAMAAJ&pg=PP7
Kuhn, B.F. 1787 Versuch fiber den Mechanismus der Gletscher (Investigation into the mechanism of glaciers). p.325-336 in G.R. de Beer (trans.) 1953 Bernhard Friedrich Kuhn's investigations on glaciers. Annals of Science, v.9 (4 - December) p.323-341 ORIGINAL 1787 publication: http://books.google.com/books?id=lZc5AAAAcAAJ&pg=PA119#v
Martel, P. 1744 An account of the glacieres or ice alps in Savoy, in two letters, one from an English gentleman to his friend at Geneva ; the other from Pierre Martel, engineer, to the said English gentleman (London, Peter (Pierre) Martel). Appendix in C.E. Mathews 1898 The annals of Mont Blanc (London, T. Fisher Unwin) http://books.google.com/books?id=oestAAAAYAAJ&pg=PA327#v
Playfair, J. 1802 Illustrations of the Huttonian Theory of the Earth in, The Works of John Playfair, 1822 Edinburgh Archibald Constable & Co. http://books.google.com/books?id=MMkEAAAAYAAJ&pg=PP11
Saussure de, H.-B. 1796 Agenda, ou tableau generale dès
observations & des secherches dont les résultats doivent servir de base à la
théorie de là terre, Chapter VIII, Observations à faire sur les cailloux roulés
p.483-484 in Voyages dans les Alpes précédés d'un essai sur l'histoire
naturelle des environs de Geneve, Volume IV (Louis Fauche-Borel, Neuchatel)
http://books.google.com/books?id=RJcaAAAAYAAJ&pg=PA483#v
Van Veen, F.R. 2008 Early ideas about erratic boulders and glacial phenomena in The Netherlands in R.H. Grapes, D. Oldroyd, and A. Grigels (eds) History of geomorphology and Quaternary geology Geological Society of London, Special Publications 301, p.159-169 http://www.google.com/books?id=-iiobjsaPnQC&lpg=PA159