franklin furnace and franklin mining district and keating and franklinite and jeffersonite and vanuxem

So it was that Keating and Vanuxem went to the vicinity of the Franklin Iron Works in August 1821 and discovered a new mineral. The narrative of their story told by Keating, though spare, allows us a glimpse into the way that these early 19th century scholars talked about scientific discovery. While some human elements are present, we are already rapidly moving into a technical vocabulary that will soon make geology and mineralogy the preserve of the specialist alone.

Getting Bearings

Keating begins by mentioning that the Franklin Iron Works were seemingly perfectly situated for abundant and profitable production of iron ore. Nevertheless, the factory had been abandoned. The "one difficulty" that intervened for the owners "arose from ignorance as to the nature of the ore intended to be worked, and of the minerals which accompany it." The owners wanted to exercise a "common process," though the minerals in the ground "required a distinct mode of treatment." Very little science would have shown the way to profitable use, but the owners did not call upon this science. The ground around the abandoned Works now lay fallow, so to speak, for enterprising scientists.

Already in 1819 a certain "Dr. Bruce," to whom Keating gives homage, had investigated the remains of the Works and discoverd a kind of "red zinc ore" which had hitherto not been discovered. At first the ore was "considered as a common iron ore," but (now the late) Dr. Bruce made arrangements for it to be sent to Paris where its properties, a combination of oxides of iron, zinc and manganese, were published in the "Annales des Mines" in 1819. The new mineral was given the name of Franklinite. The OED defines "franklinite" as "a compound of oxides of iron, manganese, and zinc, found in brilliant black crystals." I don't know how to explain the discrepancy, if one really exists, between "red zinc" and "black crystals."

The Discovery and Description

Keating mentions that once his "attention was directed with peculiar pleasure" to a bed of ore, they discovered a "number of new and interesting varieties of minerals" which should make the Franklin Furnace (as it was also called) as celebrated in mineralogy as "Uto or Arendal." He did not want to mention all their discoveries; it was sufficient for him to describe the mineral that "fully confirmed" their hunch that a new mineral was before them.

Interesting to note in his description is a thirteen-step analytical process that led him to this conclusion. It shows both the developed nature of mineralogy at that time as well as the way in which basic comparisons were still being made. He noted the following, in the following order:

1. Where the mineral was found--in "lamellar masses, the largest of which does not exceed a pigeon's eye, imbedded in Franklinite and Garnet."

2. Cleavages of the mineral. Keating spends an entire page (of a ten page article) describing the "three distinct cleavages" which "lead us for (sic) a primitive form to a rhomboidal prism, with base slightly inclined."

3. Material Hardness. Though Moh had just developed his scale, Keating did not use a number to describe it. "The hardness of the material is intermediate between that of Fluor Spar and Apatite. It is very readily scratched by Pyroxene (Malacolite)."

4. Specific Gravity. SG was between 3.51 and 3.55. One sample appared to be as high as 3.64, but Keating suspected this material to have been mixed with the (higher SG) Franklinite.

5. Color. "Its colour is dark olive-green, passing into brown.

6. Light. "It is slightly translucent upon the edges."

7. Luster. Already some of the terminology of luster, proposed by Werner about 30 years previously, is evident. The luster is "slight, but semi-metallic upon the faces of cleavage; in the transverse fracture it is resinous."

8. Fracture. "The fracture is lamellar when in the direction of cleavage, otherwise it is uneven.

9. Streak. "When scratched with a knife, the streak is grayish."

10. Color of Powder. "Light-green."

11. Blowpipe. "Before the blowpipe it melts readily into a dark coloured globule." By the way, the blowpipe was an instrument by which a current of air or gas is driven through the flame of a lamp or candle and upon a substance, in order to fuse it--an intense heat being created by the rapid supply of oxygen and the concentration of the flame upon a small area.

12. Electric and magnetic signs. It is neither electric nor magnetic, even "by the ingenious method of double magnetism which we owe to Abbe Hauy."

13. Chemical composition. The explanation of chemical structure goes on for nearly four pages, with the conclusion that "According to Professor Mohs' new and elegant mode of classifying and describing minerals, this would "form a new species, in his genus Augite Spar, and come immediately after the Pyramido-prismatic Augite Spar (Pyroxene, Hauy)." Then, Keating suggests a name for it. "On account of its many cleavages I would propose to give it as a psecific name, the epithet of polystone." But he doens't stop there. "But until Mr. Mohs' system be more generally known and approved of, it may be proper to give this mineral a name unconnected with his arragement." Mr. Vanuxem, now a resident of a state just south of the Old Dominion, "has proposed to dedicate this mineral to Mr. Jefferson; I have readily asssented to this proposal, and we now offer this mineral to the public under the name of Jeffersonite." Though the quantity is now in short supply, if it were to become abundant, it would "become valuable as a flux for the iron-works."

Conclusion

Keating concludes by summing up some points of resemblance with and difference from Hauy's Pyroxene. Comparison of cleavage, hardness and chemical analysis leads to the conclusion that "there can be no doubt as to the necessity of considering this mineral as a distinct species." Now, emboldened with his discovery, he suggests, that a "closer study of the Diopside and Fassaite, and of the Pyroxene analogique, might lead to their separation from the Pyroxene and union with the Jeffersonite." Thus, we get a small window into the nature of human life, the vagaries of time and destruction, and the progress of science.