On these properties of the rod, depends the practice of diftinguishing one Metal or fubject from another. There is, however, another way of diftinguishing, drawn from the fame principles, but much more certain and ready than the former; and that is by preparing rods, that will only operate on Gold and Copper, Iron, the white Metals, Coals, Bones, and Limestone. Thus, if a rod is wanted for diftinguishing Copper or Gold, procure filings of Iron, Lead, and Tin, fome leaf Silver, Chalk in powder, Coal in powder, and rafped bones: let a hole be bored with a fmall gimlet in the top of the rod; then mix the leaft imaginable quantity of the above ingredients, and put it in the gimlet hole with a peg of the fame wood with the rod, when it will only be attracted by what is left out, viz. Gold and Copper. In preparing a rod for diftinguishing the white Metals, leave out the Lead, Tin, and leaf Silver, and add Copper filings to the other ingredients; and fo of every fubject by which you would have the rod attracted, the refpective filings, or powder, must be left out of the mixture, which is to be put into the hole, at the top of the rod. As for Coal and Bones, they may be omitted in the distinguishing rods that are used in Cornwall, for obvious reafons: but it is neceffary to put in the Chalk or Lime; for though there is no Limestone in the Mining part of the county, yet there are abundance of ftrata that draw the rod as Limeftone; for the diftinction of a dead or a live courfe, holds as well in regard to Limestone, as to the Metals. This, however paradoxical it may appear, is a truth easily to be proved; and it is one axiom in the fcience of the rod, that it makes no diftinction between the living and dead parts of a course. Like the Lodeftone, it only fhews the course, leaving the fuccefs of the undertaking, to the fortune, skill, and management of the Miner; as the Lodeftone doth that of the voyage, to the fortune, ability, and prudence of the mariner and merchant. It is advisable for young beginners to make no experiments but about actual Lodes, where the backs of them are known by the Miners; or else nigh the fea, where a Lode being discovered, they may trace it to the cliffs, and will be fure to find it. The The rod being guarded against all fubjects except that which you want to difcover, as Tin and Copper for example; walk fteadily and flowly on with it; and a person that hath been accustomed to carry it, will meet with a fingle repulfion and attraction, every three, four, or five yards, which must not be heeded, it being only from the water that is between every bed of Killas, Grouan, or other ftrata. When the holder approaches a Lode so near as its femidiameter, the rod feels loose in the hands, and is very fenfibly repelled toward the face; if it is thrown back fo far as to touch the hat, it must be brought forward to its ufual elevation, when it will continue to be repelled till the foremost foot is over the edge of the Lode: when this is the cafe, if the rod is held well, there will first be a small repulfion towards the face; but this is momentary; and the rod will be immediately drawn irrefiftibly down, and will continue to be fo in the whole paffage over the Lode; but as foon as the foremost foot is beyond its limits, the attraction from the hindmoft foot, which is ftill on the Lode, or elfe the repulfion on the other fide, or both, throw the rod back toward the face. The diftance from the point where the attraction begun, and where it ended, is the breadth of the Lode; or rather, of a horizontal fection of the bryle or back just under the earth. We must then turn, and trace it on obliquely, or in the way of zig zag, as far as may be thought neceffary. In the course of this tracing a Lode, all the circumstances of it, fo far as they relate to its back, will be difcovered; as its breadth at different places, its being fqueezed together by hard ftrata, its being cut off and thrown afide from its regular courfe by a Cross-Goffan, &c. In order to determine this, it will be neceffary, that fome one present should either cut up a turf, or place a stone at the places where the rod began, and on the other fide where it ceased to be attracted. The draughts, in plate 2, of Veins parted and proved according to the above directions, may make this fufficiently clear. The dots represent the turf or stone; and the zig zag, the line in which the operator moves in pursuing the Vein. Fig. 5, is a Lode going on eaft and weft regularly, with the repulfion expreffed by the lines north and fouth on each fide. Fig. 6, is a Lode squeezed by a hard strata in some places almost to a string. Fig. 7, is a Lode cut off by a Cross-Goffan, wherein the method I i method for difcovering of the feparated part is obvious to any intelligent Miner, upon the fame line at grafs with the rod, as underground with the Pick and Gad. In tracing a Lode for a confiderable length, there is no neceffity for the zig zag traverfing, but it may be done according to the delineation fig. 8, wherein the operator endeavours to keep the middle of the Lode, and turns when the rod, by its repulfion, intimates that he is got beyond it. : If the rod is well held, its motion is furprisingly quick and lively nothing is neceffary, but to keep the mind indifferent, to grafp the rod pretty ftrongly, and fteadily; opening the hands, and raifing the rod with the middle fingers, every time it is drawn down. If the rod is raifed and replaced without opening the hands, it will not work. The discovery of the Metal a Lode is naturally difpofed to contain, is very eafy try it with a diftinguishing rod; if it attracts it, it contains the Metal that is left out of the mixture at the top of that rod; if it draws more than one rod, the Lode is compounded of those Metals. Copper Lodes generally draw the rod diftinguishing Iron, because of the ferruginous Goffan contained in them; but Tin Lodes frequently draw none but their proper rod, unless Gal, which is a kind of Iron Ore, is intermixed. It has been faid above, that the rod makes no diftinction between the living or dead parts of a Lode: though this is invariably true, yet this inftrument is of great use, as it helps us to trace any known Lode from the fpot where it is wrought, through other people's lands who might be willing to try it. If the Lode is alive to its top, or as it is ufually phrafed by the Tinners, To Grafs; more work may be done in the way of discovery with the rod in a quarter of an hour, than by the usual methods in months, as a perfon has nothing to do, but to open the Lode immediately at grafs, and discover its fize and underlie, which be done at a trifling expence. may The discovery of Crofs-Goffans by the rod, which may be usefully employed in Mining, is a property particularly in driving driving adits, as the driving an adit through a Cross-Goffan is much cafier than through the country. In feeking for water by the rod, no notice is to be taken of those single attractions of the rod which are occafioned by the commiffures or crevices (called Cafes of Water by the Tinners) between the courses or-diftinct runs of Killas; but a vein must be found, which anfwers to the rod as a Metal, and if this is funk unto a proper depth, a good quantity of water will be discovered. It may not be amifs to close this little effay on the Virgula Divinatoria, with fome few ftriking inftances of courses, that have been cut by means of it in Cornwall. A quantity of grain Tin having been found in the pond at Heligan, the feat of the reverend Mr. Henry Hawkins Tremayne; and it being a queftion, whether this Tin might not come from some neighbouring Lode, it was discovered by the rod and funk upon; but it proved a barren Vein for Metal in any quantity. A fhaft was funk at St. Germains, near the house of Francis Fox, to discover water; it drew the rod as Iron, and contained Mundick another fhaft was funk between Penzance and Newlyn, according to the direction of the rod; the fast lay deep beneath the furface, but a Lode containing much Mundick was discovered. In a clofe juft by St. Auftle, to fatisfy the curiofity of fome gentlemen, Mr. Cookworthy discovered by the rod the back of a Lode that had been wrought, but not turning to advantage the undertaking had been dropped, and the ground levelled. This Lode was traced juft as the Miners informed the gentlemen it ran; and the Lode appearing by the rod at a certain place to be fqueezed to nothing, the Miners declared this alfo to be true; for at this very fpot where the Lode was thus fqueezed, they loft it. Being required to discover a Lode that had been tried in the cliff under St. Auftle Down, he found it in the country by the rod, and traced it to the cliff. It was a large Goffan-Lode; and as the attraction was found to stop, and after paffing on a foot or two to begin again, he declared this was a cleft Lode, and had what the Miners call a Horse in it, which the Miners prefent who had wrought in it declared to be true. Hence it is very obvious, how useful the rod may be for discovery of Lodes, in the hands of an adept in that science; but but it is remarkable, that although it inclines to all Metals in the hands of unfkilful perfons, and to fome more quick and lively than to others, yet it has been found to dip equally to a poor Lode, and to a rich one. I know that a grain of Metal attracts the Virgula, as strongly as a pound; nor is this any difadvantage in its ufe in Mining; for if it difcovered only rich Mines, or the richer parts of a Mine, the great prizes in the Mining lottery would be foon drawn, and future adventurers would be difcouraged from trying their fortune. But, indeed, we are so plentifully ftored with Tin and Copper Lodes, that fome accident every week difcovers to us a fresh Vein; rich Mines having been feveral times difcovered by children playing, and digging pits in imitation of shafts, whereby profits have arifen to their parents and others; and these puerile discoveries have in fundry places borne the name of Huel-Boys to this day. Another way of difcovering Lodes is by finking little pits through the loofe ground, down to the faft or folid country, from fix to twelve feet deep, and driving from one to another across the direction of the Vein; fo that they must neceffarily meet with every Vein lying within the extent of these pits; for moft of them come up as high as the fuperficies of the firm rock, and fometimes a fmall matter above it. This way of feeking, the Tinners call Cofteening, from Cothas Stean; that is, fallen or dropt Tin. Another and very ancient method of difcovering Tin Lodes, is by what we call Shodeing; that is, tracing them home by loofe Stones, fragments, or Shodes (from the Teutonick Shutten to pour forth) which have been separated, and carried off, perhaps, to a confiderable distance from the Vein, and are found by chance in running waters, on the fuperficies of the ground, or a little under. When the Tinners meet with a loofe fingle ftone of Tin Ore, either in a valley, or in plowing, or hedging, though at a hundred fathoms diftance from the Vein it came from; thofe who are accustomed to this work, will not fail to find it out. They confider, that a metallick Stone muft originally have appertained to fome Vein, from which it was fevered and caft at a diftance by fome violent means. The deluge, they fuppofe, moved most of the loose earthy coat of the globe; and, in many places, washed it off from the upper, towards the lower grounds, with fuch a force, that most of the backs of Lodes or Veins which protruded |