On reaching Gratiot's Grove, I handed letters of introduction to Mr. H. and B. Gratiot. These gentlemen appear to be extensively engaged in smelting. They conducted me to see the ore prepared for smelting in the log furnace; and also the preparation of such parts of it for the ash furnace as do not undergo complete fusion in the first process. The ash furnace is a very simple kind of air furnace, with a grate so arranged as to throw a reverberating flame upon the hearth where the prepared ore is laid. It is built against a declivity, and charged, by throwing the materials to be operated upon, down the flue. A silicious flux is used; and the scoria is tapped and suffered to flow out, from the side of the furnace, before drawing off the melted lead. The latter is received in an excavation made in the earth, from which it is ladled out into iron moulds. The whole process is conducted in the open air, with sometimes a slight shed. The lead ore is piled in cribs of logs, which are roofed. Hammers, ladles, a kind of tongs, and some other iron tools are required. The simplicity of the process, the absence of external show in buildings, and the direct and ready application of the means to the end, are remarkable, as pleasing characteristics about the smelting establishment.
The ore used is the common sulphuret, with a foliated, glittering and cubical fracture. It occurs with scarcely any adhering gangue. Cubical masses of it are found, at some of the diggings, which are studded over with minute crystals of calcareous spar. These crystals, when examined, have the form of the dog-tooth spar. This broad, square-shaped, and square-broken mineral, is taken from east and west leads, is most easy to smelt, and yields the greatest per centum of lead. It is estimated to produce fifty per cent. from the log furnace, and about sixteen more when treated with a flux in the ash furnace.
Miners classify their ore from its position in the mine. Ore from east and west leads, is raised from clay diggings, although these diggings may be pursued under the first stratum of rock. Ore from north and south leads, is termed "sheet minerals," and is usually taken from rock diggings. The vein or sheet stands perpendicularly in the fissure, and is usually struck in sinking from six to ten feet. The sheet varies in thickness from six or eight inches, in the broadest part, to not more than one. The great mass found at "Irish diggings" was of this kind.
I observed, among the piles of ore at Gratiot's, the combination of zinc with lead ore, which is denominated dry bone. It is cast by as unproductive. Mr. B. Gratiot also showed me pieces of the common ore which had undergone desulphuration in the log furnace. Its natural splendor is increased by this process, so as to have the appearance of highly burnished steel. He also presented me some uniform masses of lead, recrystallized from a metallic state, under the hearth of the ash furnace. The tendency to rectangular structure in these delicate and fragile masses is very remarkable. Crystallization appears to have taken place under circumstances which opposed the production of a complete and perfect cube or parallelogram, although there are innumerable rectangles of each geometric form.
In the drive from Gratiot's to Willow Springs, we saw a succession of the same objects that had formed the prominent features of the landscape from Galena. The platte mounds, which had appeared on our left all the morning, continued visible until we entered the grove that embraces the site of the springs. Little mounds of red earth frequently appeared above the grass, to testify to the labors of miners along this part of the route. In taking a hasty survey of some of the numerous excavations of Irish diggings, I observed among the rubbish small flat masses of a yellowish white amorphous mineral substance of great weight. I have not had time to submit it to any tests. It appears too heavy and compact for the earthy yellow oxide of lead. I should not be disappointed to find it an oxide of zinc. No rock stratum protrudes from the ground in this part of the country. The consolidated masses, thrown up from the diggings, appear to be silicated limestone, often friable, and not crystalline. Galena is found in open fissures in this rock.
We reached the springs in the dusk of the evening, and found good accommodations at Ray's. Distance from Galena thirty miles.
The rain fell copiously during the night, and on the morning (18th) gave no signs of a speedy cessation. Those who travel ought often, however, to call to mind the remark of Xenophon, that "pleasure is the result of toil," and not permit slight impediments to arrest them, particularly when they have definite points to make. We set forward in a moderate rain, but in less than an hour had the pleasure to perceive signs of its mitigating, and before nine o'clock it was quite clear. We stopped a short time at Bracken's furnace. Mr. Bracken gave me specimens of organic remains, in the condition of earthy calcareous carbonates, procured on a neighboring ridge. He described the locality as being plentiful in casts and impressions such as he exhibited, which appeared to have been removed from the surface of a shelly limestone. At Rock-Branch diggings, I found masses of calcareous spar thrown from the pits. The surface appears to have been much explored for lead in this vicinity. I stopped to examine Vanmater's lead. It had been a productive one, and affords a fair example of what are called east and west leads. I observed a compass standing on the line of the lead, and asked Mr. V. whether much reliance was to be placed upon the certainty of striking the lead by the aid of this instrument. He said that it was much relied on. That the course of the leads was definite. The present one varied from a due east and west line but nine minutes, and the lead had been followed without much difficulty. The position of the ore was about forty feet below the surface. Of this depth about thirty-six feet consisted of the surface rock and its earthy covering. A vein of marly clay, enveloping the ore, was then penetrated. A series of pits had been sunk on the course of it, and the earth and ore in the interstices removed, and drawn to the surface by a windlass and bucket. Besides the ore, masses of iron pyrites had been thrown out, connected with galena. In stooping to detach some pieces from one of these masses, I placed my feet on the verge of an abandoned pit, around which weeds and bushes had grown. My face was, however, averted from the danger; but, on beholding it, I was made sensible that the least deviation from a proper balance would have pitched me into it. It was forty feet deep. The danger I had just escaped fell to the lot of Mr. B.'s dog, who, probably deceived by the growth of bushes, fell in. Whether killed or not, it was impossible to tell, and we were obliged to leave the poor animal, under a promise of Mr. V., that he would cause a windlass to be removed to the pit, to ascertain his fate.
At eleven o'clock we reached Mineral Point, the seat of justice of Iowa county. I delivered an introductory letter to Mr. Ansley, who had made a discovery of copper ore in the vicinity, and through his politeness, visited the locality. The discovery was made in sinking pits in search of lead ore. Small pieces of green carbonate of copper were found on striking the rock, which is apparently silico-calcareous, and of a very friable structure. From one of the excavations, detached masses of the sulphuret, blue and green mingled, were raised. These masses are enveloped with ochery clay.
In riding out on horseback to see this locality, I passed over the ridge of land which first received the appellation of "Mineral Point." No digging was observed in process, but the heaps of red marly clay, the vigorous growth of shrubbery around them, and the number of open or partially filled pits, remain to attest the labor which was formerly devoted in the search for lead. And this search is said to have been amply rewarded. The track of discovery is conspicuously marked by these excavations, which often extend, in a direct line, on the cardinal points, as far as the eye can reach. Everywhere the marly clay formation appears to have been relied on for the ore, and much of it certainly appears to be in sitû in it. It bears no traces of attrition; and its occurrence in regular leads forbids the supposition of its being an oceanic arrangement of mineral detritus. At Vanmater's, the metalliferous clay marl is overlaid by a grayish sedimentary limestone. Different is the geological situation of what is denominated gravel ore, of which I noticed piles, on the route from Gratiot's. This bears evident marks of attrition, and appears to have been uniformly taken from diluvial earth.
On returning to the village from this excursion, I found Mr. B. ready to proceed, and we lost no time in making the next point in our proposed route. A drive of five miles brought us to the residence of Colonel Dodge, whose zeal and enterprise in opening this portion of our western country for settlement, give him claims to be looked up to as a public benefactor. I here met the superintendent of the mines (Captain Legate), and after spending some time in conversation on the resources and prospects of the country, and partaking of the hospitalities politely offered by Colonel D. and his intelligent family, we pursued our way. The village of Dodgeville lies at the distance of four miles. Soon after passing through it some part of our tackle gave way, in crossing a gully, and I improved the opportunity of the delay to visit the adjacent diggings, which are extensive. The ore is found as at other mines, in regular leads, and not scattered about promiscuously in the red marl. Masses of brown oxide of iron were more common here than I had noticed them elsewhere. Among the rubbish of the diggings, fragments of hornstone occur. They appear to be, most commonly, portions of nodules, which exhibit, on being fractured, various discolorings.