From Giambatista Beccaria
MS not found: reprinted and translated from Latin pamphlet: De
Electricitate Vindice Joannis Baptistae Beccariae ex Scholis
Piis Ad Beniaminum Franklinium Virum de Re Electrica, &
Meteorologica optime meritum. Epistola. Taurini, Typis
Joannis Baptistae Fontana Impressoris, & Bibliopolae in Palatio
Urbis. Facultate obtenta. [1767] (Yale University Library).
[20 Februarii 1767.]
De Electricitate Vindice Joannis Baptistae
Beccariae ex Scholis Piis Ad Beniaminum Franklinium Virum De Re
Electrica, et Meteorologica optime meritum Epistola
1. Quod die 11. Septembris 1766. scribebam
tibi, Franklini clarissime: Existimare me,
errare eos, qui putarent, Simmeriano experimento theoriam infirmari
tuam; experimenta ea omnia, queis ego, et Pekinensis, et Simmeriani
experimenti analysim eram prosequutus, et totam de electricitate
vitrorum historiam auxeram, novum dumtaxat principium postulare,
quod tuis adjungeretur, et cum iisdem apprime consentiret; id
fusius nunc tandem demonstrare constitui, quum primum per
valetudinem licet mihi.
2. Itaque addendum principium est hujusmodi:
Facies vitri post explosionem, dum denundatur,
electricitatem vindicat sibi, quam habuit ante
explosionem. Atque principium hoc est, cui nomen indere placet
mihi, rem proxime significans Vindicem Electricitatem.
3. De principii caussa, ipso constituto,
quaeremus. Interea nonne magnam Physicae accessionem ii facere sunt
censendi, qui experimenta numero longe plurima specia
distractissima inveniant, a quo uno principio pendeant omnia, et
mutua veluti cognatione colligari singula cum singulis demonstrent,
quae disjunctissima videbantur, et quasi pugnantia? Imo vero nonne
in omni demum caussarum vestigatione phaenomeno alicui est denique
acquiescendum, cujur ulteriorem caussam assequi non licet? Porro
principii hujus mei, quod Vindicem Electricitatem appello, caussam
proximan explorari posse confido; sed eo ignorato hanc ignorari
debere certum est.
4. Id itaque agam in singulari libello, ut
demonstrem: Experimenta omnia, quae protuli, Electricitatem
Vindicem postulare tamquam constans phaenomenum, ad quod
referantur. Hoc posito illa explicari omnia, et reliqua vere
divinari, quae, et qualia debeant existere pro infinita, quae
potest occurrere, adjunctorum varietate.
5. Sed tibi interea, Vir clarissime, si prima
innuam, et ea certe necessaria principii consectaria, faciam satis
abunde. Neque haec memorabo, quo doceam; sed quo facias Tu
solidiora, quae natura ipsa compellit nos fundamentis superstruere
a Te constitutis.
6. Itaque, si hoc ponatur: Faciem vitri, dum
denundatur post explosionem, vindicare sibi electricitatem,
quam habuit ante explosionem, consectarium primum est: Eam
Electricitatem praepollere debere in faciem adversam;
qua voce intelligere me vides, quod est consentaneum theoriae
tuae.
7. Ex Te enim ignis extraneus, qui init in unam
vitri faciem, dispellit tantumdem ignis proprii ex facie adversa;
similiterque ignis proprius, qui eliciatur ex una vitri facie,
tantumdem extranei facit, ut affluat in faciem adversam, cujus
proprius erat veluti fulcrum. Quamobrem, si facies vitri, quae ante
explosionem redundabat, dum post explosionem denudatur, vindicat
sibi excessum ignis, quem habebat ante explosionem, hic excessus
praepollebit in faciem adversam, quae per hypothesim ab explosione
omnem amisit electricitatem; nempe tantumdem ignis nitetur
dispellere ex facie adversa, adeoque excitabit in facie adversa
atmosphaeram redundantem; scilicet excessus in eam immissus dicetur
praepollere in faciem hanc, quatenus faciet, ut haec, quae
caeteroquin non haberet nisi ignem nativum proprium, ipsa etiam
redundare videatur ob partem ignis proprii, quae pellitur, et
explicatur.
8. Similiter, si facies vitri, quae ante
explosionem deficiebat, dum post explosionem denundatur, vindicat
sibi defectum, quem habebat ante explosionem, hic defectus
praepollebit in faciem adversam, quae item per hypothesim ab
explosione omnem amisit electricitatem; nempe tantumdem ignis
extranei alliciet in faciem adversam; adeoque excitabit in facie
adversa atmosphaeram deficientem; scilicet defectus in eam
denudatione inditus dicetur praepollere in faciem hanc, quatenus
faciet, ut haec, quae caetoroquin haberet ignem nativum suum, ipsa
etiam deficere videatur ob partem ignis extranei, quem jam plane
expostulat, atque allicit ad sese.
9 Itaque, quo multa paucis, eaque satis
perspicue omnia eloqui valeamus, nomina licebit condere aliqua,
quibus has, affinesque alias in vitris electricitatum habitudines
significemus: Et primo quidem summam ignis redundantis in facie
una, et deficientis in facie adversa, quae explosione nullescit
tota, et cui adeo proportione respondet explosionis magnitudo,
appellabiums nomine, uti puto, satis consentaneo Electricitatem
vitri absolutam, et veram; unde similiter totus excessus, aut
totus defectus in facie una vitri, dicetur absoluta, et vera
ejus faciei Electricitas.
10. Deinde ipsam, quae intercedat aliqua, inter
excessum faciei unius, et defectum alterius differentiam,
Electricitatem relativam sive apparentem dicemus;
quod ea sola appareat, et agat, quum vitrum aut indutum, aut exutum
exploratur, quin attrectetur facies utraque simul ad explosionem
ciendam.
11. Sed haec iterum apparens electricitas
distinguetur excessus adjuncto, si excessus faciei unius sit major
defectu adversae, vel contra, si defectus sit major excessu; Sic si
vitri facies A, excessum majorem habeat defectu adversae faciei B,
in vitro inerit Electricitas apparens excessus; sin
defectus faciei B sit major excessu faciei A, vitrum erit
electricum defectu apparente.
12. Atque ad singulas distinguendas in singulis
faciebus electricitates hujusmodi, faciem A in primo exemplo
electricam dicemus excessu determinante, et faciem B
excessu determinato electricam dicemus. Contra in exemplo
altero faciem B appellabimus electricam defectu
determinante, faciem A electricam defectu
determinato.
13. Unde etiam universe eae voces obvenient
familiares Electricitas, aut Facies determinans, et
Electricitas, aut Facies determinata.
14. Neque demum erit supervacaneum
electricitatem apparentem aliam dicere solitariam, aliam
conjugatam: Ceu cum facies una vitri excessum ignis habet
sine ullo respondente in facie adversa defectu, aut contra facies
una defectum habet sine ullo respondente in facie adversa excessu,
vitrum excessu, aut defectu solitario electricum
dicetur. Sin excessui majori aliquis jam respondeat in facie
adversa defectus, aut majori defectui excessus aliquis: vitrum
excessu, aut defectu apparente conjugato erit
electricum.
15. Quibus quidem in partitionibus non vereor,
ne videar Tibi ineptire, Franklini clarissime, ut poteqi videas,
eas vocum differentias expostulari a differentiis rerum, ceu
alterum demonstrat, quod ex constituta vindice electricitate
sequitur consectarium.
16. Scilicet: Apparens a denundatione
electricitas, si coetera constent eadem, maxima sit
oportet: Est enim electricitas solitaria excessus, aut
defectus, qui primo existit in facie una, dum facies adversa ab
explosione egnem nativum habet; prima autem, auqe init in faciem
vitri electricitas, maxima est, et maximam habet vim determinandae
contrariae in facie adversa electricitatis; sunt enim datae caussae
effectus initiales, qui sunt semper maximi. Itaque quemadmodum (ne
a re discedamus nostra) cum principio vitrum obijcimus catenae, ut
fiat electricum, prima, quae in contiguam vitri faciem init
scintilla, est maxima, et maxima est prima, quae a facie adversa
dispellitur in solum, et scintillae consequentes decrescunt usque,
et usque magis; ita prima, et solitaria, quae a denundatione vitri
emicat iterum post explosionem electricitas, maxima sit oportet, et
maxima vi contrariam determinet in facie adversa
electricitatem.
17. Atque hinc manifestum existit consectarium
tertium: Electricitates homologas a denundatione post
explosionem apparentes in utraque vitri facie vi maxima
tendere ad aequalitatem. Scilicet electricitas determinans vi
maxima tendit ad nihilum: intereaque facit, ut electricitas
apparens determinata vi maxima nitatur abire in absolutam ipsi sibi
contrariam, et aequalem. Quod abstractum consectarium singulari
exemplo est omnino perspicuum: Nam, si ponas, post explosionem
denundari faciem A, quae ante explosionem redundabat, ipsa
vindicabit sibi vi maxima pristinum excessum, qui vi maxima partem
ignis nativi pellet ex facie adversa (16); adeoque maxima erit
mutua, et contraria ejus excessus in ignem hunc nativum, et ignis
hujus nativi in eum excessum actio. Igitur ille excessus ab igne
hoc nativo vi maxima retropelletur, ut discedat, et abeat in
nihilum, atque interea ille excessus dispellet aequali vi ignem
nativum, ut discedat, et defectus ita existat excessui
aequalis.
18. Exempli contrarii eadem est ratio.
Phaenomena enim omnia illa tenenda docent principia tua. I. Ignem
in vitro librari utrinque cum igne nativo corporum extraneorum,
quotiescumque summa ignis in vitro sit utlibet aequalis summae
nativae. II. Ignem in vitro praepollere utrinque in ignem nativum
corporum extraneorum, quotiescumque summa ignis in vitro sit
utlibet major igne nativo. III. Ignem corporum extraneorum
praepollere utrinque in ignem vitri, quotiescumque ignis in vitro
sit utlibet minor igne nativo.
19. Quare, cum post explosionem denudatur facie
vitri B, quae ante explosionem igne deficiebat, ipsa a denundatione
sibi vindicat pristinum defectum, quin facie adversa, quae
disjuncta est a corporibus deferentibus, respondentem excessum
possit comparate sibi; summa ergo ignis nativi vitro contingentis
toto eo defectu erit minuta; igitur ignis extraneus praepollebit
undique, et nitetur se expandere in faciem deficientem, quo
defectum minuat, atque in adversam, quo excessum producat defectui
aequalem, itaque nativam ignis dosim restituat vitro. Quae omnia vi
contingent maxima ex allata caussa.
20. Reenimvera, quae post explosionem a
denudatione reviviscunt electricitates, signa electrica pro sua
magnitudine edunt maxima omnia, scintillas, motus, auram.
21. Quae ipsa res quartum ferme facit
Electricitatis Vindicis consectarium, nempe: Si facies post
explosionem denudata iterum induatur, et vitrum attrectetur,
aut amittit electricitatem vindicatam, si attrectetur in
facie determinante, quae suit denudata, aut absolutam acquirit, et
illi contrariam, et aequalem, si attractetur in facie
adversa; etenim attrectare, seu universe objicere corpus
deferens corpri, cujur electricitas vi maxima tendat in nihilum,
est quasi viam electricitati ipsi facere, qua evanescat; Itaque
quando ex proximo consectario electricitas determinans denudatione
excitata vi maxima tendit in nihilum, attrectatione facei ipsius
determinantis in nihilum abibit.
22. Similiter attrectare, seu corpus deferens
objicere corpori electricitatem appetenti est viam facere, qua
ipsam assequatur; sed ex proximo consectario facie vitri
determinata vi maxima appetit electricitatem absolutam contrariam,
et aequalem determinanti; igitur attrectatione hanc assequetur.
23. Neque vero in sola denudatione obtinet
electricitas vindex; sed adhuc magis universe decremento ipsi, quod
capit electricitas dati corporis, cohibentis, dum admovetur ad
datam a dato corpore distantiam, electricitas respondet, quae ipsi
a vi vindice restituitur, cum iterum removetur.
24. Atque ex his paucis, quae ab uno fluunt
omnia principio, quasi necessariis consectariis reliqua jam fluunt
omnia, quae scribebam in specimine altero. Quemadmodum enim,
denudata una facie, invalescit utrinque in vitro ejus faciei
electricitas, quae obtinebat ante denudationem; Ita liquet,
denudata altera, invalescere debere utrinqué alterius
electricitatem; Unde intelligitur, quemadmodum a denudatione
facierum vitri, aut vitorum plurium, quae ante et post explosionem
fiat ordine eodem, electricitates ante et post explosionem
appareant contrariae; quam rem primam appellabam ex explosione
electritatum oscillationem; quae tamen appariturae sin eaedem, si
facies vitri, aut vitrorum ante et post explosionem denudentur
ordine contrario.
25. Atque huic rei si addas Vis Vindicis
constantiam, qualem experientia demonstrat, ut nempe duret dum
vitra ad horas integras denundantur, et iterum induuntur; perspicua
est ratio electricitatis in vitro, vel in vitris admirabiliter
horas integras oscillantis ex indusii a vitro, aut vitri a vitro
disjunctione, et conjunctione.
26. Evanescit similiter omnis earum
oscillationum admirabilitas, quas inveni contingere ex inversione
vitri tenuioris. Quam tamen ad rem hoc facit experimentum.
27. Duas laminas vitreas tenuem aliam, aliam
crassiorem, caetera aequales singulis catenae ramis objicio
singulas, ut eodem tempore vi eadem electricaefiant; Tum praehensas
angulis subtraho ambas laeva unam, dextera aliam. Socius adest, qui
bacillis cerae signatoriae separatos singulis singulos duos habet
in promptu arcus ex metallicis virgis sinuatos in formam literae S.
Continuo uno eorum arcuum, communicationem insert inter facie duas
unam redundantem in vitro uno, aliam in alio deficientem; Similiter
alio eorum arcuum facit, ut communicent reliquae duorum vitrorum
facies duae: Singulis singulorum arcuum ad vitrorum facies
appulsibus scintillulae existunt, quas theoria tua postulat, atque
appulsu ultimo, quo communicatio absolvitur, explosio existit. Sed
tum, si digitis attrecto utrinque vitrum crassius, ipsum quidem jam
nullatenus explodit; si tenujus, explosionem experior ab ipso
reliquam crassitiei vitri alterius proportionalem:
28. Quamobrem pro majore vitri crassitie major
necessaria est ad inferenda electricitates contrarias in oppositas
ejus facies. Quidni igitur quod tenuius est vitrum majore vi
pristinam sibi a mutua, quae fiat post explosionem, interiorum
facierum per disjunctionem denudatione, vindicet electricitatem?
Atqui dum vitrum tenuius invertitur, interior quae fit ab
inversione facie, ante explosionem electricitatem habebat illi
contrariam, quae faciei contingebat antea interiori.
29. Adde demum ultimum, quod est plane
necessarium, Vis Vindicis consectarium: Electricitati primo
immissae ipsam magnitudine respondere; et jam liquet,
quamobrem in experimento Pekinensi longe omnium pulcherrimo, utpote
primo in eo genere, abeant in contrarias electricitates inversione
vitri, quod unum principio electricum factum est, non item
inversione alterius, quod electricitatem accepit illius
communicatione.
30. Atque ex his, ut inquiebam, non experimenta
ipsa solum, sed et experimentorum limites, atque varietates omnes
facile intelliguntur. Non vereor vero ego, ne obscurior videar
Tibi, dum studui esse brevior, qui paucis assueveris docere longe
plurima. Vale.
Augustae Taurinorum die 20. Februarii 1767.
31. P. S. Quae de vitro dixi, eadem constituenda de corporibus
cohibentibus omnibus, quae non transmeat electricus ignis, et
analoga de aliis cohibentibus, quae transmeat, ceu sunt tibialia
Simmerii, ad quae omnia latissime pertinet Electricitas Vindex, ceu
necessaria vis cohibentis affectio pro ipsius vis modo, et
magnitudine. 32. Fit inde, ut etiam ante explosionem vitra, ubi jam
semel sunt denudata, Vim Vindicem habeant aliquam. 33. Ad modum
vero quod attinet ejus Vis Vindicis, cum nitor ego electricum
facere vitrum, vel vitra, quae calent admodum, scintillae utrinque
existunt perpetuae. Ignis ergo electricus tum vel permeat, vel
circuit. Experimentum habeo, quo rem plane definiam. Interea id
videre videor: Electricitates in vitro, vel in vitris hujusmodi,
quae admodum caleant, per explosionem neutiquam abire in
contrarias, neque per inversionem. 34. Episcopus Mutinensis vir
doctissimus aeque, et spectatissimus, et Pater Troilius e Societate
Jesu nuper scripserunt de lapide, qui superiore aestate observatus
est Alboreti dilabi e caelo. Perspecta observationum historia,
opinatus sum: Lapidem hunc a fulmine in aerem disjectum, similiter
ac electric scintilla aquae guttulam disjiciente explodere ego
soleo ligneum globulum ad hexapedas duas, aut etiam quatuor.
Reenimvera eo tempore fulminabat, tonabat, tonitru exauditum,
observata fulguratio socia fulminis phaenomena, perspectae
scintillae in facie proximi rivi. Similia fulminantis caeli
adjuncta consectabantur similes lapidum lapsus, quorum historiam
apte refert Troilius. Placuit opinio mea, et visa scientiam facere
portenti naturae, quod summan omni aevo habuit adjunctam
admirabilitatem aeque, ac vanam superstitionem. Atque, uti addit
doctissimus Episcopus, id etiam perbelle congruit, solum Mutinense
scatere undique proxima aqua. Quare fulmen per lapidem, qui erat
metallicus, effundens se in subiectam aquam debuit disjicere hanc,
efferre illum in sublime obvolutum luce sua, ne cerneretur, nisi
postmodum cum relaberetur.
[Translation:] On Vindicating Electricity Of
Giambatista Beccaria of the Sacred Schools A Letter to Benjamin
Franklin A Man of Great Merit in Electrical and Meteorological
Matters
Turin, February 20, 1767.
1. I wrote to you, my distinguished Franklin,
on September 11, 1766, that I thought they are wrong, who think
your theory is invalidated by Simmer’s experiment; that all those
experiments (in which I followed up the analysis of the Pekin and
Simmer’s experiment, and furthered the whole investigation of the
electricity of glasses) demand a new principle, which may be joined
with yours, and which especially agrees with yours. This I have now
at last decided to demonstrate more fully, when my health first
allows me.
2. Thus the principle to be added is as
follows: A surface of glass after an explosion, while it
is discharged, frees [vindicat] for itself the electricity
which it had before the explosion. And this is the principle to
which I am pleased to give the name, closely expressing the effect:
Vindicating Electricity.
3. Now that the principle has been set up, we
shall seek to learn its cause. Are not they to be regarded as
having made a great advance in Physics, who devise experiments, the
greatest in number and most diverse in appearance, and show from
what one principle all of them depend, and that separate phenomena
are bound with each other as if by a mutual
relationship—[phenomena] which before appeared most independent and
almost contrary? Indeed, in every investigation of causes, must one
not be finally content with any phenomenon, the more remote cause
of which one cannot pursue? Hence I trust that I am able to explore
the immediate cause of my principle, which I call Vindicating
Electricity; but while the principle itself remains unknown, it is
certain that the cause must remain unknown.
4. Therefore I shall do that in a special book,
to demonstrate: That all the experiments that I have devised demand
that we postulate Vindicating Electricity as a constant
phenomenon to which the experiments may be referred; once this is
posited, all those things are explained, and others truly deduced,
what and of what sort ought to exist in relation to the infinite
variety of adjuncts that can occur.
5. But if in the meantime, illustrious Sir, I
sketch for you my basic propositions and the really important
inferences, I shall certainly have done enough.
6. Thus, if this is posited: that a surface
of glass, after an explosion, frees [vindicare] for itself
the electricity it had before the explosion, the first
inference is: that electricity ought to charge [praepollere]
into the opposite surface—by which word you see that I
understand what agrees with your theory.
7. For, according to you, the excess fire,
which enters one surface of a glass, drives out from the opposite
surface the same amount of fire; and likewise its own fire which is
drawn out of one surface of a glass makes the same amount of excess
fire flow into the opposite surface, of which its own [fire] was
like a fulcrum. Wherefore, if the surface of a glass, which had an
excess before the explosion, frees for itself the excess fire it
had before the explosion, the excess charges into the opposite
surface, which according to the hypothesis set free all its
electricity with the explosion; for, of course, it will try to
drive out the same amount of fire from the opposite surface, and so
will produce in the opposite surface an excess atmosphere;
obviously the excess sent into it will be said to charge into that
surface, with the result that what would otherwise have only its
own natural fire seems itself to have an excess on account of its
own fire that is driven out and set free.
8. Similarly, if the surface of a glass that
was deficient before the explosion is discharged after the
explosion, it frees for itself the deficiency it had before the
explosion, this deficiency will charge into the opposite surface,
which, likewise according to the hypothesis, has set free all its
electricity with the explosion; for, of course, it will attract the
same amount of fire into the opposite surface; and so will produce
in the opposite surface a deficient atmosphere; of course, the
deficiency imposed on it by the discharging will be said to charge
into that surface, with the result that that which otherwise would
have its own natural fire, seems itself even to be deficient
because of the part of the excess fire it now clearly demands and
attracts to itself.
9. Therefore, to speak briefly but clearly, it
will be desirable to invent some terminology by which we may
signify these and other related conditions of electricity in
glasses: First, even the total sum of excess fire in one surface
and of deficient fire in the opposite surface, all of which is
nullified by the explosion and to which the magnitude of the
explosion corresponds proportionately, we shall call by a name
appropriate enough, I think: the absolute and true
electricity of glass; whence similarly the total excess or
total deficiency in one surface of a glass will be called: the
absolute and true electricity of that surface.
10. Then the Difference itself, which somehow
occurs between the excess of one surface and the deficiency of the
other, we shall call relative or apparent
electricity, because that only appears and acts when a glass
charged by excess or deficiency is tested, unless both surfaces are
touched simultaneously to produce an explosion.
11. But again this apparent electricity will be
distinguished by the characteristic of excess if the excess of one
surface is greater than the deficiency of the opposite one, or on
the contrary, if the deficiency is greater than the excess; thus,
if the surface A of the glass has a greater excess than the
deficiency of the opposite surface B, there will be in the glass
apparent excess electricity; but if the deficiency of
surface B is greater than the excess of surface A, the glass will
be electric by apparent deficiency.
12. In order to distinguish the different
electricities of this sort in each of the surfaces, we shall call
surface A in the first example electric by the determining
[determinante] excess, and surface B electric by the
determined [determinato] excess. On the other hand, in the
other example we shall call surface B electric by the
determining [determinante] deficiency, and surface A
electric by the determined [determinato]
deficiency.
13. Whence will come the universally familiar
terms: determining Electricity or the determining
surface, and determined Electricity or the
determined surface.
14. Nor finally will it be superfluous to call
one apparent electricity simple [solitariam], the other
conjugate [conjugatam]: just as when one surface of a glass
has an excess of fire with no corresponding deficiency in the
opposite surface, or on the other hand one surface has a deficiency
with no corresponding excess in the opposite surface, the glass
will be called electric by simple excess or
deficiency. But if to a greater excess some deficiency
responds on the opposite side, or to a greater deficiency some
excess, then the glass will be electric by apparent conjugate
excess or deficiency.
15. In these definitions I have no fear that I
might seem silly to you, illustrious Franklin, since you will see
that these distinctions in terminology are demanded by real
distinctions, as the other inference shows, which follow from the
posited principle of vindicating electricity.
16. Obviously, electricity arising from
discharge, if other things are constant, must be the
greatest; for there is simple electricity by excess or by
deficiency, which exists in one surface while the opposite surface
has natural fire from the explosion; the first electricity,
however, which enters the surface of the glass is the greatest and
has the greatest power of determining contrary electricity in the
opposite surface; the initial results of a given cause are always
the greatest. Thus, according to our principle (lest we depart from
our present subject) in whatever way we touch the glass to the
chain to make it electric, the first spark to enter the contiguous
surface of the glass is the greatest, and the first to be driven
out from the opposite surface into the ground is the greatest, and
subsequent sparks decrease more and more; thus the first, simple
electricity which flashes forth from the discharge of the glass
again after the explosion must be the greatest and must determine
with the greatest force the contrary electricity in the opposite
surface.
17. And from this there exists a third
inference: homologous electricities arising from the
discharge after an explosion tend toward equality in each
surface of the glass with the greatest force. For of course
determining electricity tends with the greatest force to nothing;
and meanwhile it causes apparent determined electricity with the
greatest force to try to pass into absolute [electricity] equal and
opposite to itself. Which abstract inference is altogether clear
from a single example: for, if you assume that surface A is
discharged after the explosion and that before the explosion it had
an excess, then it frees for itself with the greatest force its
original excess, which drives with the greatest force part of the
natural fire from the opposite surface (16); and thus the mutual
action of its excess upon its natural fire, and of its natural fire
upon its excess, will be contrary and maximum. Therefore that
excess will be repelled with the greatest force by the natural
fire, so that it vanishes and passes into nothing, and meanwhile
that excess drives out the natural fire with an equal force, so
that it vanishes, and thus a deficiency exists equal to the
excess.
18. The reason for the opposite example is the
same. All these phenomena show that your principles must be
maintained. I. The fire in a glass is held in balance on both sides
with the natural fire of external bodies, whenever the total of the
fire in the glass is equal to the natural quantity. II. The fire in
glass charges from both sides into the natural fire of external
bodies, whenever the total of the fire in the glass is greater than
the natural fire. III. The fire of the external bodies charges from
both sides into the fire of the glass, whenever the fire in the
glass is less than the natural fire.
19. Therefore, when after the explosion the
surface B of the glass is discharged, which before the explosion
had a deficiency of fire, it frees for itself by the discharge the
original deficiency without the opposite surface, which has been
separated from conducting [deferentibus] bodies, being able
to obtain for itself a corresponding excess; therefore, the
quantity of natural fire touching the glass will be decreased by
that total deficiency; and therefore, the excess fire will
discharge everywhere and will try to expand itself into the
deficient opposite surface, by which it lessens the deficiency and
produces an excess equal to the deficiency, and thus restores to
the glass its natural quantity of fire. All which things happen
with the greatest force from the assumed cause.
20. For indeed, the electricities which are
recovered from the discharge after an explosion give all the
greatest signs in proportion to their magnitude, sparks, movements,
wind.
21. Which thing itself makes the fourth
inference of Vindicating Electricity, that is: If a surface
discharged after an explosion is again charged by excess,
and the glass is touched, either it loses the vindicating
electricity, if it is touched in the determining surface that
was discharged, or it acquires absolute electricity contrary
to that and equal, if it is touched on the opposite
surface; for to touch, or generally to present a deferent body
to a body whose electricity tends with the greatest force into
nothing is as it were to make a path for the electricity itself
through which it vanishes; and thus since from the previous
inference determining electricity excited by discharge tends with
the greatest force into nothing, by the touching of the determining
face itself it will pass into nothing.
22. Likewise to touch, or to present a deferent
body to a body seeking electricity, is to make a path by which it
may obtain [electricity]; but from the previous inference the
determined surface of the glass seeks with the greatest force
absolute electricity contrary and equal to the determining
electricity; therefore it follows this by the touching.
23. Nor indeed does vindicating electricity
hold in discharge, but still more generally the electricity
corresponds to the decreasing of itself, which the electricity held
by a given body within itself experiences, while it is moved to a
given distance from a given body; and this electricity is restored
to it by the vindicating force when it is again removed.
24. And now from these few, if necessary,
inferences, all of which follow from one principle, all the
remaining inferences follow, which I wrote about in another
publication. For just as, once one surface is discharged, the
electricity of that surface, which was acquired before the
discharge, grows stronger on each side of the glass, so it will
follow that when the other surface is discharged the electricity of
the other on each side ought to grow stronger; whence it is
understood how, from the discharge of a glass, or of several
glasses, which discharge came about before and after the explosion
in that same order, opposite electricities appear before and after
the explosion, which phenomenon I first called from the explosion
oscillation of electricities; which nevertheless would appear the
same, if the surface of a glass, or glasses, are denuded before and
after the explosion in the opposite order.
25. And if you add to this phenomenon the
constancy of the Vindicating Force, which constancy, experiment
shows, lasts for whole hours while the glasses are discharged and
charged again, the reason is clear for the oscillation of the
electricity in glass (it lasting surprisingly for whole hours in
glasses) whether by the separation of cloth from glass or of glass
from glass, or their conjunction.
26. Likewise all the wonder of their
oscillations disappears, which [oscillations] I found to happen
from the inversion of a thinner glass. This is shown by this
experiment:
27. I connect two glass plates, one thinner,
the other thicker, but equal in other respects, individually to
separate branches of a chain, so that they become electric at the
same time and with the same force. Then I remove both of them,
taking them by the corners, one on the left, the other on the
right. An assistant is present, who has ready two separate curved
metal rods, each with a handle of sealing wax, bent into the shape
of the letter S. With one of these rods he promptly establishes
communication between two surfaces, one charged to excess in one
glass, the other charged by deficiency in the other glass.
Likewise, with the other of these rods he connects the remaining
two surfaces of the glasses. From each contact of each of the
curved rods sparks arise to the surfaces of the glasses, which your
theory demands, and at the final contact, by which the
communication is ended, an explosion takes place. But then, if I
touch with my finger the thicker glass on each side, it now does
not explode at all; but if I touch the thinner, I experience a
subsequent explosion proportional to the thickness of the other
glass.
28. Wherefore, in proportion to the greater
thickness of the glass a greater force is necessary to bring
contrary electricity into its opposite surfaces. Is it not,
therefore, because a thinner glass frees for itself with greater
force the original electricity from the mutual discharge that
occurred after the explosion of the interior surfaces through
separation? Then, while a thinner glass is inserted, the surface,
which becomes the inner from the inversion, had, prior to the
explosion, electricity contrary to that which was previously on the
inner surface.
29. Add a final inference of Vindicating Force
that is clearly necessary: The Force corresponds in magnitude to
the electricity first admitted. And now one can see why in the
Pekin experiment (that most splendid of all, as well as the first
of its kind) electricities change into the contrary by the
inversion of the glass that alone was made electric in the
beginning, not similarly by the inversion of the other that
receives electricity by the communication with it.
30. And from these things, as I was saying, not
only are the experiments themselves easily understood, but the
boundaries of the experiments and all their variety. In truth, I do
not fear that, while I am eager to be concise, I will seem to you
rather obscure, you who are accustomed to teach many things in a
few words. Farewell.
31. p.s. What I have said about glass must
also be established for all insulating [cohibendibus] bodies
through which electric fire does not pass, and is analogous to
other insulating bodies through which electric fire does not pass,
just as Symmer’s stockings, to all which things Vindicating
Electricity most broadly pertains, as a necessary aspect of
restraining force in relation to the manner and magnitude of the
force itself. 32. It happens then that once glasses are discharged
they have some Vindicating Force even before an explosion. 33. In
connection with the manner of this Vindicating Force, when I try to
make a very warm glass or glasses electric, continual sparks arise
on both sides. Therefore the electric fire either goes through or
around. I have an experiment by which I clearly define the
phenomenon. Meanwhile, I seem to see this: electricities in glass
or glasses of this sort, which are very warm never change into
contrary electricities by an explosion or by inversion. 34. The
Bishop of Modena, a man equally learned and revered, and the Jesuit
Father Troilius recently wrote about a stone which was observed
last summer to fall from heaven at Alboretium. When the history of
these observations is reviewed I believe that the stone was cast
into the air by a thunderbolt, just as I am accustomed to explode
an iron ball a distance of two or even four rods by an electric
spark dispersing a drop of water. For indeed at that time it was
thundering and lightning, thunder was heard, lightning (the allied
phenomenon of the bolt) was observed, sparks were seen on the
surface of a nearby stream. Similar effects of lightning in the sky
accompanied similar falling stones, of which Troilius gives a good
account. My judgment is that these sights explain the portent of
nature, which in every age has excited the greatest wonder as well
as vain superstition. And, as the learned bishop adds, this
confirms remarkably that the soil at Modena is everywhere full of
the nearby water. Wherefore the bolt, driving through the stone,
which is metallic, into the water beneath should scatter the water
and hurl the stone into the air while covered in its own flash, so
that it be not seen until afterwards, when it falls back down.
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