Grégory Quenet
50
buried deep in the Earth’s crust.
45 Yet for all these differences, the
mechanism for propagating earth tremors remained the same, as the
“fluide électrique” was transmitted instantaneously through all conducting bodies, whether they be mountains, veins of sulphur, or other
substances. For Isnard, the electrical “principle” is the only one capable of explaining all the particular effects of earthquakes: electricity
penetrates objects without losing anything of its power, it strikes matter both externally and internally, it produces detonations and showers
of sparks, it passes through the hardest bodies as lightning does, and is
luminescent. The most compelling argument for contemporaries remained electricity’s ability to travel enormous distances in a trice just
as earth tremors did.
46 Isnard cites Louis-Guillaume Le Monnier who
in 1746 was the first to estimate the speed of electricity: detecting no
time delay between seeing lightning flash and feeling it strike, he deduced that the electrical charge travelled at thirty times the speed of
sound. Le Monnier also noted that an electrical current crossed an expanse of water, such as the pond in the Tuileries gardens, without losing any of its power. Even more spectacular experiments were carried
out in this vein by Jean Jallabert around Lake Geneva and by William
Watson and other members of the Royal Society in London in 1748
when they would send currents across rivers by means of two iron
bars plunged simultaneously into the water.
47
___________________________
45 “Les tremblemens de terre attribués à l’électricité”, Journal encyclopédique (1
er mai
1756), III, pp. 3-18; “Essai sur les tremblemens de terre”, Mercure de France, (mai
1756), pp. 93-113; “Réflexions sur les causes des tremblemens de terre”, Journal de
Trévoux, (décembre 1756), pp. 3012-16.
46 Isnard, Mémoires sur les tremblemens de terre, p. 27.
47 John Lewis Heilbron, Electricity in the 17th and 18th centuries: a study of early
modern physics (Berkeley; London: University of California Press, 1979), p. 320.
50
buried deep in the Earth’s crust.
45 Yet for all these differences, the
mechanism for propagating earth tremors remained the same, as the
“fluide électrique” was transmitted instantaneously through all conducting bodies, whether they be mountains, veins of sulphur, or other
substances. For Isnard, the electrical “principle” is the only one capable of explaining all the particular effects of earthquakes: electricity
penetrates objects without losing anything of its power, it strikes matter both externally and internally, it produces detonations and showers
of sparks, it passes through the hardest bodies as lightning does, and is
luminescent. The most compelling argument for contemporaries remained electricity’s ability to travel enormous distances in a trice just
as earth tremors did.
46 Isnard cites Louis-Guillaume Le Monnier who
in 1746 was the first to estimate the speed of electricity: detecting no
time delay between seeing lightning flash and feeling it strike, he deduced that the electrical charge travelled at thirty times the speed of
sound. Le Monnier also noted that an electrical current crossed an expanse of water, such as the pond in the Tuileries gardens, without losing any of its power. Even more spectacular experiments were carried
out in this vein by Jean Jallabert around Lake Geneva and by William
Watson and other members of the Royal Society in London in 1748
when they would send currents across rivers by means of two iron
bars plunged simultaneously into the water.
47
___________________________
45 “Les tremblemens de terre attribués à l’électricité”, Journal encyclopédique (1
er mai
1756), III, pp. 3-18; “Essai sur les tremblemens de terre”, Mercure de France, (mai
1756), pp. 93-113; “Réflexions sur les causes des tremblemens de terre”, Journal de
Trévoux, (décembre 1756), pp. 3012-16.
46 Isnard, Mémoires sur les tremblemens de terre, p. 27.
47 John Lewis Heilbron, Electricity in the 17th and 18th centuries: a study of early
modern physics (Berkeley; London: University of California Press, 1979), p. 320.