At opposite sides of the spout. L, and in a direct radial line with each other, are two sets of bottom less compartments, J1. 1C, divided by partitions from one another and froin the spout, L. The apportioning device, 1, comprises an annular trough, 0, divided preferably into eight hopper-like compartments terminating in outlets, P. directly over chutes, AL and being provided with adjustable sports, Q, which may be tented to discharge into the spouts, L, or paths of the chutes, A/ and X. 1i is a hopper into which the crushed ore is fed, and whence, by the action of the spiral blade, S, it is discharged in a uniform stream through the spoilt, '1, into the rotating trough, 0, so that one-eighth tort of the mass will pass out at each spout, Q. By a certain adjustment, of the spouts, Q. six-eighths of the entire mass down will fall into the annular spout, L. and be discharged at the inner spout of guide chutes, J. Gne-eighth portion of the mass passing, down through the spout, Q. which extends over the annultir path of the chute, iI. is distributed equally over the said path, one-eighth part of the said eight portions into each of the distributing chutes, ;If, and the remaining six-eighths thereof into the confluent chutes, IT, whence it passes with the first discarded six-eighths clown through 1-he spouts, L, to the chute. The mass is again divided by passing into the apportioning device, 0, and two approximately equal samples of the mass are obtained in the guide chutes, J. The machine is adjustable to give samples of different size. Its capacity is from 15 to 25 tons per hour, and it is claimed that it will sample satis factorily Material of any character; ore with over 10 per cent. moisture even offering no diffi culty. It takes feed directly from crusher or rolls, regularly or irregularly, and requires no attention except for cleaning out and removal of samples. Prior to the introduction of this machine at the Mile Island Copper Works, states Mr. Bridgeman, 54 car-load lots (of about 80,000 lbs, each) of copper matte had been treated, on which duplicate samples were made by hand. The average assay contents cf these 54 lots were : oz. gold, oz. silver. 55'24 per cent. copper. The average differences between the two samples of each lot were 0 43 oz. gold, 3'77 oz. silver, per cent. copper. Since the introduction of the machine, 23 lots of ore and 138 lots of matte have been run, the latter being, of the seine general char acter as the hand-sampled matte, except that it did not, as a rule, carry so much lies." 13y reason of these " metallics." much of this matte was very difficult to sample accu rately, as will be easily understood. The weights of these 100 lots varied from 65 His. to 42.000 lbs., averaging not less than 30,000 lbs. 'their average assay contents were 0-71 oz. gold. oz. silver, per cent. copper. The average differences between the two samples of each lot were 0'02 oz. gold, 1'19 oz. silver, per cent. copper. Reduced to percent ages for the sake of comparison. the average differences were as follows : 51 hand samples —gold, ; silver, 2-21 ; copper, 160 machine samples—gold, 2.82 ; silver, 106; copper, 0445.
Bridgeman'e Small _Machine (Fig. 6) is a modification of the large ma chine. Its particular field of usefulness is the quick and certain cutting down of the miscellaneous small samples (from 5 lbs. to 50) lbs. in weight) that are constantly being received by assay offices. It will handle anything from the finest assay pulp to
crushed material of -I in. or more in size. In operation, the ma terial is fed either by hand or (with large lots) from a suitably supported bucket into the funnel, F, the divider, 14 being first set in rotation by hand, clockwork, or any convenient power. The divider gives, as will be seen by inspection of the drawing, eight cuts to the revolution, four being delivered to the funnel, 1, and four to the. receptacle, 2; that is, with uniform flow and speed, cutting the material in half The divider may easily run 100 revo lutions per minute. giving in that time 800 cuts, a very much greater distribution and division than can be secured in any other way. The rejected sample posses down the outlet to 0 into any suitable vessel. T he retained portion, should it be too large, may be cut again and again, until of suitable size. The operation is very accurate and rapid ; about as fast as the material will flow through a 1-in. spout.
Bridgeman's Mixer and Divider (Fig. 7) for ore samples is an apparatus designed to obviate the tedious and frequently inaccurate methods—usually with oil-cloth and spatula—in general use, for mixing and dividing the ground samples of ore, matte, slag, and other similar material The operation is as follows : The ground material is introduced into the large covered funnel (mixer), the outlet being first closed by thumb or finger, as may be most convenient. Funnel and contents are then well shaken for a few minutes, and then, with opened out let, passed to and fro over the set of distributing funnels (divider) and bottles, as shown. With very finely ground, or very light ma terial, the flow may be assisted by a slight shaking or tapping with the hand. The little skill necessary is readily acquired. To test the efficiency of the mixer, Mr. II. L. Bridgeman took a mixture of 6 assay tons of litharg,e. 3 assay tons of soda, and assay ton of argols ; it was well shaken, divided by weight into three lots, of 31 assay tons each, and these charges fused separately in crucibles. The resulting lead buttons weighed gins., gins., and gins., respectively.
The 110nley Ore machine differs radically from others, as it combines the features of both the time-dividing, and the stream-dividing types of ore samplers ; and, again, as it furnishes two samples, each serving as a check on the accuracy of the other. The ore, previously crushed by rolls or crushers, or both, is fed through a revolving screen, or may be conveyed directly, to a large hopper, in which there is an oscillating wing, driven by an eccentric rod deriving its motion from a shaft, on which are centered other eccentrics per forming the same operation at a later stage of the sampling. This oscillating wing in its passage cuts the stream into two portions, one of which passes directly to the floor, and the other is cut in its descent by a second oscillating wing into two portions again, passing into separate compartments. This operation can be extended in a properly constructed machine until as small a sample as one-sixteenth of the original amount is arrived at, and this divided into two portions, which are crushed fine and again quartered in samples fit for the grind ing plate. Each is assayed separately, and they are said to agree within extremely close limits.