uncertainties that must unavoidably attend the search for such metals as occur in mineral veins, particularly in a new country. These uncertainties arise chiefly from the difficulty of estimating before hand, with exactness, the quantity of the metal sought, that any area in the plane of the vein may produce. This results from three circumstances, the varying proportions in the thickness or form of the vein, the varying proportions of the pure ore in its distribution in this irregular form, and the varying proportions of the pure metal in the irregularly distributed ore. The form of the vein may be compared to that of a very extensive and profound rough-surfaced fissure, (without known limits either way,) the opposite sides of which having slipped on one another, do not fit, but touch in some parts, stand asunder in others, and approach and recede in endless fluctuations, while multitudes of fragments, cracked off and fallen from the walls, caught and suspended in the crevice, and often resting upon one another in a loose mass, block up various parts, leaving a general space, so irregular, as to defy all attempt to determine it with precision by any rule. The swelling and attenuating, knotted, perforated and ragged sheet which would fill this mould is the vein, and it is composed of a mechanical mixture of earthy and metallic minerals, as irregular in their proportional distribution as the sheet is in the measurements of its thickness. In some few spots it may be wholly pure ore; in many large and small areas, it may consist of the earthy minerals without any ore at all; and in the remainder, it may consist of any indefinite proportion of the two that lies between all and nothing. The pure ore or metallic minerals are definite chemical compounds, in which the metal is held in fixed proportions, according to the species of the minerals, as found described in mineralogical works; and the irregularities in regard to them arise from two or more species being frequently mechanically mingled together, in proportions as indefinite as those relating to the earthy and metallic minerals. It is evident from this, that the quantity of pure metal, in any given area in the plane of a mineral vein, can be only approximatively ascertained, by arbitrarily assuming as data for calculation the results of experiments on parts. The more numerous and extensive the parts selected the nearer will be the approximation to the truth; and those portions of a lode available for such a purpose, are the outcrop when uninjured by atmospheric influences,

horizontal galleries or levels, and vertical or inclined shafts. The edges of the concealed metalliferous sheet, as displayed in these natural and artificial exposures, may be assumed to represent the whole included within them to moderate distances, and by measuring and sampling them, data for practical purposes arrived at. Nine times out of ten, the results may bear out the calculations from such data; but it should be borne in mind, that any particular case may turn out to be the tenth one, and give results much beyond, or very much below the computation.

As affording the best criterion of the quality in the present instance, the ores and vein-stuff which had been brought to the surface from the various levels, shafts and excavations, were sampled as near to the Cornish mode as circumstances would permit. When copper ores are sampled for sale in Cornwall or at Swansea in Wales, the whole parcel having previously been broken up into pieces not exceeeing an inch or half an inch cube, is arranged into a square, even-surfaced pile, not exceeding two or two and a half feet in depth. Two trenches at right angles to one another are then cut from side to side opposite through the centre. The sides of these trenches are next scraped down into the bottom, and what is thus obtained is mixed together and bruised much finer than before, being passed through a seive to insure the fineness, and then made up into a small flat pile which is split as before. This operation is repeated three times, a smaller-holed seive being used at each, and a requisite degree of fineness and mixture thus obtained. If the resulting quantity is too large for a sample, it is made up into a small flat circular pile, marked into quadrants, and two opposite quadrants removed. The remainder is mixed up again and the operation repeated generally about five times, when the resulting quantity is about small enough to be sent to the assayer for his purposes. In the present instance it would have been too expensive and tedious a process to break up the ores to a uniform size. The piles were consequently split as they stood on the ground, but the resulting quantity was carried through all the other operations. The weights of the piles were roughly estimated by measurement. When there were no parcels of ore to experiment upon for produce, the lode having been previously measured for average width generally at every fathom was drilled across at an angle of about 45° at regular measured intervals, and the powder coming from

the bore-holes taken as samples; when, from great width in the vein, one hole would not reach from wall to wall, then two or more were drilled as the case might require. Two gangs of men of three each, with one to superintend and collect the borings, were employed at this work for upwards of a month. At first the distances were appointed at every two fathoms apart, subsequently at every three, and as my time drew to a close, they were extended to five fathoms; but even thus, the lodes were in some places so wide and the exposures so long, that it was found impossible to drill-sample the whole satisfactorily, particularly on the west side of the location.

The position of the location will be well indicated by stating that the 84th meridian of west longitude from Greenwich passes lengthways through the middle of it nearly. It is one of those which belong to the Montreal Mining Company, and in it are situated the Bruce Mines so well known throughout the Province. The size of the location, or sett as it would be termed in Cornwall, like that of most of the other locations is two miles in front by five in depth running exactly north. The surface is gently undulating, the ridges ranging from S. E. to N. W. The rocks which compose them are greenstone, syenitic conglomerate with its associate slate, and quartz-rock. The rear and nearly the whole of the front are occupied by greenstone spread out to some breadth; quartz-rock, syenitic conglomerate and slates, with bands of greenstone (probably dykes) are met with in the intermediate space. The limestone band which has been mentioned in the general description has not been observed on the location, but it approaches to within about half a mile of it on the Thessalon in the rear; and a similar rock occupies the water-line of the farthest off half-front of the next location westward, in the position already mentioned as three quarters of a mile above the French Islands. If continued southeastwardly in its strike until abreast of the south-easterly extremity of the second Island, the band would be about a mile and a half in a transverse direction from the Bruce Mines' wharf, apparently in about the same relation to the greenstone of the front, as the Thessalon rock is to the greenstone of the rear. There are copper lodes in both the ranges of greenstone, but only those in the front part of the location have been opened.

The front lodes are several in number, and occupy positions towards both sides of the location. There is a rude parallelism to

one another in some parts of the lodes and an apparent convergence in others, and the whole are attended with a great complication of branches, which probably run from one to another and connect the whole iuto one system, emanating from some one great disturbance, the results of which, will no doubt traverse all the western locations in succession which cross its direction, mineralising the country through which they pass, according to the quality of the rock encountered. At the Bruce Mines the surface rock these lodes and their branches intersect, is wholly greenstone, and the branches as well as the main veins, have copper present in them in various proportions. In the configuration of the coast, there is a conspicuous peninsula joined to the main land by a narrow marshy strip. about one third of the location's breadth from the western boundary. If a north-west line, or a line with a bearing approaching to N. 55 W., be carried through the neck of this peninsula, and another be drawn parallel to it across the location, at the distance of twenty-five to thirty chains farther in, they will probably include all the mineral ground related to the front lodes; and the belt thus formed, starting from the western boundary with its full breadth, will come obliquely upon the coast, its northeast side terminating on the lake, inside of a point which is about three quarters of a mile from the east boundary line of the location, and limits a deep bay occupying the distance. The length of the belt would thus be about one mile and a quarter, and it constitutes a low ridge rising to between sixty and seventy feet above the level of the lake.

From the immediate vicinity of the point just mentioned, one of the main veins runs nearly a straight course, N. 40 W., for rather over three hundred fathoms. The first one hundred and seventy-five of these fathoms not offering an encouraging quantity of ore, have had no work bestowed upon them; natural exposures of the lode occur at intervals only in three places, making up seventy fathoms, and the intermediate spaces are still covered with trees and vegetation. The average breadth of the lode in these exposures is six feet, but the traces of copper in them were so scarce that it appeared to me useless to sample them by drilling. In the succeeding thirty fathoms, there was but one exposure; it occupied the first eight fathoms and shewed a breadth of four to six feet. About four fathoms of it displayed a surface bunch of ore promis

ing about half a ton of 15.00 per cent ore per fathom. The Company, however, having set miners to stope, (or excavate) these four fathoms, the estimated quantity soon diminished to a little over half the amount; these four fathoms are marked on the Company's Map as Stope No. 24. A few drill-holes (from the position of the exposures at irregular intervals) were bored in the 205 fathoms. The sample resulting, gives a produce of only 0.61 per cent.; the chief part of the copper being probably from the last portion of the distance.

The succeeding eighty fathoms, reaching up to the east end of what is called the Trial Shaft, were drilled across at intervals of five fathoms along the outcrop, the borings from the drillholes of each twenty fathoms, being kept seperate for assay, and the average width of the lode in the same spaces determined. The results are as follows:

The remaining fifteen of the 300 fathoms, including that part of the lode occupied by the Trial Shaft, were not sampled, but they will probably not differ much either in produce or width from the last section of the eighty fathoms, in the whole of which the species of copper ore prevailing appears to be almost altogether the pyritous, neither the vitreous nor the variegated having been met with in any quantity. The second score in the above list includes four fathoms, situated near the powder magazine, and marked as Stope No. 1 in the Company's Map. Before my departure from the mines these four fathoms had been excavated to the depth of about six feet, and the ore presented on the bottom a much better appearance to the eye than it had done on the surface. The last six fathoms of the fourth score constitute Stope No. 2, and being situated next to the Trial Shaft, may probably without much error, be taken to represent what the produce of the shaft was at the top. If such be the case, the lode must have improved downwards in the shaft. About forty tons of vein-stuff, taken from the shaft, and lying on the surface, when the depth was between four