This is a poem from a paper Historia Inventionis Phosphori by Leibniz, written in 1710, correcting the account of the discovery of phosphorus. Translating this paper has been a perennial project of mine, it's not long but I haven't quite had the skill to approach some sections. This poem is Leibniz writing about phosphorus and its discoverer. I'll post the poem, and my working translation (warts and all), which I'm looking for help with.
Here is the full poem which is typeset and corrected: Google Books Leibniz Gesammelte Werke lines 175-212. This version has several differences and clarifies some intended meanings.
First, about phosphorus: The phosphorus being discussed is a form of white phosphorus, which can glow brilliantly and will react by bursting into flames if it is not kept under water. You can see demonstrations of it in this video from Thoisoi2. Phosphorous was produced by boiling down urine, then letting it ferment for 3-4 months. Leibniz respected the original discoverer, Hennig Brandt.
Ille vagum poterat radio describere mundum,
Et signare vias pelagi [stellasque cadentes]
[Et rerum arcanas vires] sacrosque recessus,
Abdita quos natura sine contexit avaro:
Quaeque Prometheae furatrix virgula flammae
Attulit, & nostris patrat miracula furnis:
Omnia tentabat discendi nobilis ardor.
Vidimus haud unquam visum mortalibus ignem:
Frigidus hic mediis servari gaudet in undis,
Paulatim exhalans, patrios ne repetat orbes;
Fragmina perspicui simulare putes Electri.
Nam lapis est, lapidem placet appellare Pyropum,
Ignotum Natura tibi, ni doctior illum
Nuperus artifici coqueret Vulcanus in antro.
Et fors, ni tanti spectaclum Principis esse
Debuerat, veluti latuit, per secla lateret.
Hunc si Persa sacrum coluisses credulus ignem,
Non te pertusa lusisset Nilus in olla.
Noster inextinctis imitatur viribus astra,
Et quaesita Sophis, veterumque afficta sepulchris
Unus perpetuae nutrit vitalia flammae
Nec Vestalis eget. Jeremias conderet illo,
Quod sua posteritas patriis accenderet aris.
Ardentem in tenebris timeas tractare lapillum
Inscius: ille tamen nil tactu laedit, & ultro
Corpoream rebus lucem mirabile dictu
Affricat, & Mosis faciem mirantibus offert,
Parte vel a minima tingentibus omnia flammis.
Innocuus, ni fors hostili durius ausu
Tractetur, nimio motu tunc concipit iram
Horribili fremitu, verisque ardoribus urit [alt: veroque exaestuat igne],
Omnia corripiens, & longa incendia miscet.
Promptius Assyriam possis extinguere naphtham,
Phasidis aut pulsae tunicam, lethalia dona.
Cum tumulatus aquis nimio discedit ab aestu,
Dissimulat vires: tantum cum forte movebis,
Admotave manu facies sentire calorem,
Impiger emisso testatur fulgure vitam,
Immortale animae referens emblema beatae, &c.
Working English Translation.
He had been able to describe the uncertain world with a straight line,
And indicate the paths of the sea, and its sacred recesses,
Which hidden Nature covered under her covetous bosom,
And which Prometheus's thieving rod of flame
Had brought; and Brand performed the miracle with our furnaces,
His noble ardor for learning tried everything.
We saw a fire never before seen by mortals:
This one rejoices to be kept under cold water,
Gradually evaporating, that it may not return to its native world.
You may think the fragments are similar to transparent Amber,
As it is a stone, a stone you like to call Pyropum.
Unknown by Nature, but that our more learned modern
ulcan had prepared it in his artificial cave.
And perhaps, but that it was a spectacle deserving of a Prince,
it would have remained hidden, as it was, through the ages.
If you, credulous Persian, had tended this sacred fire,
The Nile would not have toyed with you in a perforated pot.
Our inextinguishable fire imitates the stars in its power;
And alone it nourishes the vitality of perpetual flame,
That sought by the Wise, and affixed to the sepulchres of the ancients;
And it wants not for a Vestal. Jeremiah would have hid it in that place,
Which his posterity might kindle by ancestral altars.
In darkness, you, ignorant, may fear to handle the burning stone,
Yet it wounds nothing by touch, and itself
Imparts to things a corporeal light (mirabile dictu!)
And offers the face of Moses to the wonderous,
With even the smallest piece tinging everything in flame.
Harmless, unless perhaps by a hostile attempt it is handled
More roughly, then by excessive motion it is stirred to fury,
With dreadful roaring and true ardor it burns,
Seizing everything, and spreading long lasting flames.
You would be sooner able to extinguish Assyrian naphtha,
Or the tunic of the spurned Colchian, her lethal gift.
When buried in water it withdraws from excessive glowing heat,
It conceals its power, yet when by chance you move it,
Or it should feel heat by your approaching hand,
It confidently attests its life by an emitted flash,
Recalling the undying emblem of the blessed soul, etc.
Gloss.
This poem excerpt is from Epicedium in Obitum Serenissimi Principis ac Domini Domini Johannis Friderici Brunsvicensium et Luneburgensium Ducis ad Reverendissimum ac Celsissimum Principem ac Dominum Dominum Ferdinandum Episcopum Paderbornensem et Monasteriensem &c. Hannover, 1680, lines 175-212. (Google Books link). Published in Leibnizens Gesammelte Werke, Bd. 4. (1847)
The lines "stellasque cadentes / Et rerum arcanas vires" appear in the original but not in this version.
The line "verisque ardoribus urit" was originally "veroque exaestuat igne."
The lines "Promptius Assyriam possis extinguere naphtham, / Phasidis aut pulsae tunicam, lethali dona." do not appear in the original poem linked above.
pelagus -i n (Greek) = mare (sea)
Pyropum = Another name for the substance now known as phosphorus
Persa = a Persian, referring to Zoroastrian fire worship
Jeremias -ae = Jeremiah, prophet of the Hebrew Bible who hid the sacred flame
Facies Mosis = the face of Moses, which glowed brilliantly when he descended Mt. Sinai after being in the presence of God
Assyria = Country of Asia, now Kurdistan. Assyrian naphtha is a highly flammable petroleum product, which was used for incendiary devices in the Roman era.
Phasis -idis = (here) Colchian; Phasidis tunicam refers to the Colchian tunic (or robe) of Medea, poisoned to burst into flames, used to kill Jason's wife Glauce; this was referenced earlier in the paper as "tunica Madeae".