De Re Metallica Part 27

" 4th = 2 "

" 5th = 1 " = 24 units of 4 _siliquae_ each.

" 6th = 12 units of 4 _siliquae_ each.

" 7th = 6 " "

" 8th = 3 " "

" 9th = 2 " "

" 10th = 1 " "

And so with them, just as with our own people, the _mark_ is divided into two hundred and eighty-eight _grenlins_, and by the people of Nuremberg it is divided into two hundred and fifty-six _pfennige_.

Lastly, the Venetians divide the _bes_ into eight _unciae_. The _uncia_ into four _sicilici_, the _sicilicus_ into thirty-six _siliquae_. They make twelve weights, which they use whenever they wish to a.s.say alloys of silver and copper. Of these

the 1st = 8 _unciae_ = 1 _bes_.

" 2nd = 4 "

" 3rd = 2 "

" 4th = 1 " or 4 _sicilici_.

" 5th = 2 _sicilici_.

" 6th = 1 _sicilicus_.

" 7th = 18 _siliquae_.

" 8th = 9 "

" 9th = 6 "

" 10th = 3 "

" 11th = 2 "

" 12th = 1 "

Since the Venetians divide the _bes_ into eleven hundred and fifty-two _siliquae_, or two hundred and eighty-eight units of 4 _siliquae_ each, into which number our people also divide the _bes_, they thus make the same number of _siliquae_, and both agree, even though the Venetians divide the _bes_ into smaller divisions.

This, then, is the system of weights, both of the greater and the lesser kinds, which metallurgists employ, and likewise the system of the lesser weights which coiners and merchants employ, when they are a.s.saying metals and coined money. The _bes_ of the larger weight with which they provide themselves when they weigh large ma.s.ses of these things, I have explained in my work _De Mensuris et Ponderibus_, and in another book, _De Precio Metallorum et Monetis_.

[Ill.u.s.tration 265 (Balances): A--First small balance. B--Second.

C--Third, placed in a case.]

There are three small balances by which we weigh ore, metals, and fluxes. The first, by which we weigh lead and fluxes, is the largest among these smaller balances, and when eight _unciae_ (of the greater weights) are placed in one of its pans, and the same number in the other, it sustains no damage. The second is more delicate, and by this we weigh the ore or the metal, which is to be a.s.sayed; this is well able to carry one _centumpondium_ of the lesser weights in one pan, and in the other, ore or metal as heavy as that weight. The third is the most delicate, and by this we weigh the beads of gold or silver, which, when the a.s.say is completed, settle in the bottom of the cupel. But if anyone weighs lead in the second balance, or an ore in the third, he will do them much injury.

Whatsoever small amount of metal is obtained from a _centumpondium_ of the lesser weights of ore or metal alloy, the same greater weight of metal is smelted from a _centumpondium_ of the greater weight of ore or metal alloy.

END OF BOOK VII.

FOOTNOTES:

[1] We have but little record of anything which could be called "a.s.saying" among the Greeks and Romans. The fact, however, that they made constant use of the touchstone (see note 37, p. 252) is sufficient proof that they were able to test the purity of gold and silver. The description of the touchstone by Theophrastus contains several references to "trial" by fire (see note 37, p. 252). They were adepts at metal working, and were therefore familiar with melting metals on a small scale, with the smelting of silver, lead, copper, and tin ores (see note 1, p. 353) and with the parting of silver and lead by cupellation. Consequently, it would not require much of an imaginative flight to conclude that there existed some system of tests of ore and metal values by fire. Apart from the statement of Theophrastus referred to, the first references made to anything which might fill the _role_ of a.s.saying are from the Alchemists, particularly Geber (prior to 1300), for they describe methods of solution, precipitation, distillation, fusing in crucibles, cupellation, and of the parting of gold and silver by acid and by sulphur, antimony, or cementation. However, they were not bent on determining quant.i.tative values, which is the fundamental object of the a.s.sayer's art, and all their discussion is shrouded in an obscure cloak of gibberish and attempted mysticism. Nevertheless, therein lies the foundation of many cardinal a.s.say methods, and even of chemistry itself.

The first explicit records of a.s.saying are the anonymous booklets published in German early in the 16th Century under the t.i.tle _Probierbuchlein_. Therein the art is disclosed well advanced toward maturity, so far as concerns gold and silver, with some notes on lead and copper. We refer the reader to Appendix B for fuller discussion of these books, but we may repeat here that they are a collection of disconnected recipes lacking in arrangement, the items often repeated, and all apparently the inheritance of wisdom pa.s.sed from father to son over many generations. It is obviously intended as a sort of reminder to those already skilled in the art, and would be hopeless to a novice.

Apart from some notes in Biringuccio (Book III, Chaps. 1 and 2) on a.s.saying gold and silver, there is nothing else prior to _De Re Metallica_. Agricola was familiar with these works and includes their material in this chapter. The very great advance which his account represents can only be appreciated by comparison, but the exhaustive publication of other works is foreign to the purpose of these notes.

Agricola introduces system into the arrangement of his materials, describes implements, and gives a hundred details which are wholly omitted from the previous works, all in a manner which would enable a beginner to learn the art. Furthermore, the a.s.saying of lead, copper, tin, quicksilver, iron, and bis.m.u.th, is almost wholly new, together with the whole of the argument and explanations. We would call the attention of students of the history of chemistry to the general oversight of these early 16th Century attempts at a.n.a.lytical chemistry, for in them lie the foundations of that science. The statement sometimes made that Agricola was the first a.s.sayer, is false if for no other reason than that science does not develop with such strides at any one human hand.

He can, however, fairly be accounted as the author of the first proper text-book upon a.s.saying. Those familiar with the art will be astonished at the small progress made since his time, for in his pages appear most of the reagents and most of the critical operations in the dry a.n.a.lyses of gold, silver, lead, copper, tin, bis.m.u.th, quicksilver, and iron of to-day. Further, there will be recognised many of the "kinks" of the art used even yet, such as the method of granulation, duplicate a.s.says, the "a.s.say ton" method of weights, the use of test lead, the introduction of charges in leaf lead, and even the use of beer instead of water to damp bone-ash.

The following table is given of the substances mentioned requiring some comment, and the terms adopted in this book, with notes for convenience in reference. The German terms are either from Agricola's Glossary of _De Re Metallica_, his _Interpretatio_, or the German Translation. We have retained the original German spelling. The fifth column refers to the page where more ample notes are given:--

Terms Latin. German. Remarks. Further adopted. Notes.

Alum _Alumen_ _Alaun_ Either pota.s.sium p. 564 or ammonia alum

Ampulla _Ampulla_ _Kolb_ A distillation jar

Antimony _Stibium_ _Spiesglas_ Practically always p. 428 antimony sulphide

_Aqua valens_ _Aqua valens_ _Scheidewa.s.ser_ Mostly nitric acid p. 439 or _aqua_

Argol _Feces vini _Die Crude tartar p. 234 siccae_ weinheffen_

Ash of lead _Nigrum Artificial lead p. 237 plumb.u.m sulphide cinereum_

Ash of musk ivy _Sal ex _Salalkali_ Mostly potash p. 560 (Salt made anthyllidis from) cinere factus_

Ashes which _Cineres quo Mostly potash p. 559 wool-dyers use infectores lanarum utuntur_

a.s.say _Venas experiri_ _Probiren_

a.s.say furnace _Fornacula_ _Probir ofen_ "Little" furnace

Azure _Caeruleum_ _Lasur_ Partly copper p. 110 carbonate (azurite) partly silicate

Bis.m.u.th _Plumb.u.m _Wis.m.u.t_ _Bis.m.u.th_ p. 433 Cinereum_

Bitumen _Bitumen_ _Bergwachs_ p. 581

Blast furnace _Prima fornax_ _Schmeltzofen_

Borax _Chrysocolla ex _Borras; Tincar_ p. 560 nitro confecta; chrysocolla quam boracem nominant_

Burned alum _Alumen coctum_ _Gesottener Probably p. 565 alaun_ dehydrated alum

_Cadmia_ (1) Furnace p. 112 (see note accretions (2) 8, p. 112) Calamine (3) Zinc blende (4) Cobalt a.r.s.enical sulphides

Camphor _Camphora_ _Campffer_ p. 238

Chrysocolla called borax (see borax)

Chrysocolla _Chrysocolla_ _Berggrun und Partly p. 110 (copper Schifergrun_ chrysocolla, mineral) partly malachite

Copper filings _Aeris scobs _Kupferfeilich_ Apparently finely p. 233 elimata_ divided copper metal

Copper flowers _Aeris flos_ _Kupferbraun_ Cupric oxide p. 538

Copper scales _Aeris squamae_ _Kupfer Probably cupric hammerschlag oxide oder kessel braun_

Copper minerals (see note 8, p. 109)

Crucible _Catillus _Dreieckicht- See ill.u.s.tration p. 229 (triangular) triangularis_ schirbe_