724 
On Thunderbolts. 
[December, 
existence in their language of a word corresponding to 
la foudre in the French tongue. To show again that the 
term thunderbolt is not a diCtionary-maker’s refinement for 
the translation of la foudre, I beg to call attention to the 
English version of Arago’s “ Meteorological Essays,” com- 
piled by the late Sir Edward Sabine, President of the Royal 
Society (London, 1855.) In this translation “ la foudre ” 
is repeatedly rendered by the word “ thunderbolt.” For 
instance, “ Seneca defined thunderbolts as lightnings that 
reach the ground ” [p. 24 abridged] . “ Maffei, Chappe, and 
others, deem that ” . . . “ thunderbolts are almost always 
elaborated on the ground.” [p. 101.] “ Thunderbolts develope 
by their action, in the places where the explosion takes 
place, often smoke, and almost always a strong odour.” 
[p. 62] “ I admit, without reservation, the existence of 
ascending thunderbolts .” [p. 176] . And, lest it should be 
conceived that the term la foudre was used by the French 
for thunderstones as well as for thunderbolts, I may here 
mention that their expression for thunderstone is meteor olithe, 
a word which seems to give the so-called thunderstone what 
is probably its true scientific status, viz., that of a meteorite 
or aerolite. 
It may now, however, reasonably be asked whether, 
supposing the word “thunderbolt” to be the proper English 
term for a lightning stroke, it is even then an expedient one 
to restore to general use. In reply, I should be inclined to 
give my opinion in the negative. An erroneous meaning 
having once been attached to it by scientific authorities, 
there would probably be some difficulty in rehabilitating it 
with its correct signification, and I think that the expression 
lightning stroke would, for the present, and until our know- 
ledge of terrestrial dynamics becomes enlarged, be more 
fitting for general adoption. But I would submit that no 
objection should ever be urged to the employment by 
educated men of the legitimate, old-fashioned term thunder- 
bolt, should they desire to use it. And I would urge this 
the more particularly inasmuch as I think that the word 
represents with scientific accuracy the principal character- 
istics of all lightning strokes. These appear to me, so far 
as my researches have extended, to be first a clap of thunder 
of exceeding loudness, and secondly a figurative bolt or 
arrow of irresistible force piercing or rending the materials 
with which it comes in contact. There are on record several 
undeniable lightning strokes or thunderbolts in which no 
lightning has been seen ; but I doubt if any strokes can be 
found in which no thunderclap was heard. And as regards 
