and coarse sand, varying according to circumstances, but espe cially to the abundance of water and the rapid movement of the stamps. The workman from time to time gathers it with a shovel and throws it into the bed. So far as relates to the water which flows off charged with sand and slimy ore, this goes to the basins of classification. 2. Basins and Recesses--Classification of pulverized ore.—The basins of classification and the deposit of pulverized ore which escape comprise : 1st. Four wooden boxes of 1m. 90 in length, 0m. 70 in breadth, 0m. 50 depth, along which two channels run to a square section of 17 to 18 centimetres on the side-one a for pulverized ore, and the other b leading to the recesses; these channels have little gates or outlets to establish an easy communication. 2d. A recess (labyrinth) consisting of twelve or fifteen basins in masonry 1 metre in length, except the first, of which the section is a little larger. They are placed side by side, and over the whole length run little covered channels furnished with gates or outlets, in order to pass at the proper time the water from one basin to the other. These channels end in grand reservoirs, still larger, whence the water passes to the river. By means of the outlets in the channel a we cause the slimy water to flow into those of the four boxes, which are empty or still free; whilst one is cleared they open the gates or outlet of another, and thus avoid any suspension of labor. Whatever may be that of these boxes which are filled, the water after having deposited the sand escapes in the conduit b and pass to the basin of the recess of which they regulate the fulness by means of the outlets. According to the nature of the deposit at the point of washing, we discriminate only five numbers of slimy ore in the basins of the recess, -as the transverse dimensions of these basins differ but little, there is beside but little difference in the richness and fineness of these five numbers. Each stamp-mill is served by 2 workmen, laboring each 12 hours per day of 24 hours. When the stoppages are not considerable, we can count an average of 10 to 12 tons of stuff passed in 24 hours by a stamp machine of 15 or 16 stamps. During certain months of the year, when water is abundant and other circumstances favorable to steady work, 13 to 14 tons are passed in a day. 3. Washing of Sand and Slimy Ore.-To each of these two classes of products the work and apparatus correspond. The three shops or sheds of shaking tables contain one for sand and two for slimy ore of the corresponding stamp-mill. 3. Working of the Sand B-The shaking tables consist of a plank strengthened by cross pieces 4 metres long to 1m. 40 wide. At the head of the table is a small inclined plane, furnished with This prism-shaped brackets to divide the slime for washing. apparatus is sustained as usual by four iron chains, of which two are fixed behind, and the two others can be lengthened or shortened by a windlass placed in front. The shaking movement is communicated to the head by a system of bent levers, moved itself by a shaft, and cams common to the three tables in the same shop. Behind and above the head of the table is a circular hopper, where the sand is stopped with the water for washing. This distributing apparatus, like certain revolving tubs used on the borders of the Rhine, is composed of a wooden hopper, in pieces, having the large base 090 in diameter, the small one 0m. 10 to 0. 135. It is sustained by an iron axis, and terminates towards the bottom in a toothed circle, a communicating mechanism is geared with the teeth of this circle, which makes it turn, and with it the hopper, by jerks, around the iron axle. In this movement, the sands carried by the water fall to the distributor in a small channel placed below, and which opens on the inclined plane at the head of the table. In short, at the foot of the table are channels or trenches by which the water passing from the works goes to the river or to special basins. Working the sand B is done in a very rapid manner on these tables; they reach the inclined plane at the head of the tables, and are there divided into little threads which occupy the whole breadth of the table. With a wooden scooper, the workman from time to time removes the stuff from the foot to the head. So far as relates to the essential details of the work, that is to say, the quantity of water used, the continuation and extent of the shake, the inclination of the tables, we have not been able to procure precise and uniform particulars. We refer that subject to the skill and tact of the washing master. The washing of the sand is done with two trials, and the following are the products yielded : First Trial. of the length down from the head goes to the second trial. of the tail is regarded as first stuff of the first trial. Slimy water goes to the river. Second Trial. of the length from the head, is fine ore for the foundry. Slimy water goes to the river after passing into special basins, where they deposit very pyritous sand, which is washed in the same manner for fine pyritous ore delivered to the foundries. The basins of pyrites are usually four in number, 2 metres to 2m. 20 in length, 0m. 60 in breadth, 0m, 40 to 0m. 45 in depth. Working the Fine Ground Ore B B B of Various Numbers. The tables for fine ground ore (schlamms) differ but little from that for sand; they are constructed in the same manner, and with the same dimensions as the first,-the little falls which present their floor make the only peculiarity. The distributing apparatus on the contrary differs very much. The jerks imparted to the hopper of sand do not answer for delaying the ore, which is very slimy, as it comes from the recess. There is a nacelle adapted to the alternate and continued movement, in which comes a constant little stream of water. This nacelle is moved in a wooden box, of a pyramidal truncated form and square base; the bottom of this box slightly inclines toward the conduit which connects it with the table, leaving between itself and the external wall of the nacelle a space of some centimetres. It is by this space that the matters delayed in the water of the nacelle escape by its oscillatory motion, and gain the conduit which leads to the table. Apart from this arrangement for delaying and bringing the slime ore on the tables, we have nothing new to state respecting the working of the slimy ore of various numbers and of various products; two trials are made, yielding each time products analogous to those of the sand. We do not mention the quantity of water, the continuity and fulness of the shake, &c., which are details varying with the number of the slime to be worked; these variations in general are very small. Each shop of three shaking tables is attended by 7 workmen 12 hours. I master washer; 3 servants, one for each table; 1 child having charge of the flow of slime and sand on the table and of the clearings; 2 laborers for emptying the basins and transports. Without comprehending the fine pyritous ore, the average product of a table of fine ore sands is 200 to 250 kilogrammes for 12 hours, but this figure is below what can be obtained by constant labor; the product of a table of sand may be 500 to 600 kilogrammes per 12 hours. Besides the slimy ores, every shop of three tables produces in addition an average of 50 to 60 kilogrammes of fine pyritous ore, whether sand or slime. The products sent to the foundry shops for washing with shaking tables belong to three classes, sand, fine ground ore, pyrites. The force required for a crible shop, the wet stamp-mills, and the shaking tables required, is presented in the following tables, with the price of a day's work of the different classes of laborers, and the time of work-a day being 12 hours. A Crible Shop Working 6 or 7 Full Months. 1 breaker or picker....1f. 50 2 stampers...... 1 washer.. 1 sifter.... .....If. 50 each I refiner at the German Three Stamp-mills working 8 or 9 months. .1f. 50 .1f. 50 Three Washing Shops for Same Time. 3 master washers... 9 servants.... 3 children. 6 laborers. 2 fr. each. .1 fr. 10 to 1 f. 50 each. Let us now examine in a general manner the products of the mechanical preparation, the entire treatment adopted at Vialas, its advantages and disadvantages. The numerous stoppages and intermissions of work at most of the apparatus, render impossible a reunion of all the corresponding products of different operations with certainty of a common origin. Unfortunately no assay either of raw materials or products is made at Vialas. We do not refer now to a great number of assays made on various products which do not always correspond; but among our results are some that allow us to appreciate the principal circumstances of the mechanical preparation;-these only we shall notice. The excellence of the mechanical preparation depends on a large number of details, among which we shall notice only the nature of the ore, the expense of labor, but especially the loss in metallic matter, the importance of which often more than overbalances the economy in other respects from a more rapid operation. How often has the attempt been made in various districts of metallic mines to diminish the loss of useful substances; especially has the effort been made to diminish the slimy ore by more careful sortings; the loss of silver and lead increases elsewhere, and the first often more than the second, with the degree of the richness of the fine ground ore (schlich), and the washing of slimy matters has been pushed less far. Now, all these precautions will be so much more necessary at Vialas, as the ore is very rich in silver, and also in consequence of the circumstances of the metallurgical treatment; the loss at the foundry and at the roasting tends to increase with the richness of the schlich. Under all these considerations, it will be good to profit by the experience of others, and modify a little the mode of preparation, and even some of the apparatus. In sorting, only two distinct classes are made, riddling and stamping sorts. The galena is very often disseminated in the ore, but in some veins more particularly than in others; certain ores have more quartz or barytes, others more slate. Whatever may be their nature, the ores are nevertheless mixed. The breaking which precedes the sorting is not pushed far enough. It results from this that the class called stamp contains often samples which a better sorting would give to the crible; for the latter, a more careful breaking and sorting would give more massif, especially if, aside from the general principles above mentioned, a lower standard was sought in the products sent to the foundry. The following average assays better determine our appreciation: The ore of the crible bas yielded 30 to 60 per cent, of pig lead; we speak of the coarse ore. The crible sand No. 2 and 3 have yielded by dry assay 0.50 per cent. of lead, and g 37.50 per cent.,-on average 04 to 45 per cent. in pig lead of ore of the crible. On the other side, 100 of the ore sent to the crible yielded25 fin sec., sifting No. 2 and No. 3 washed. 25 mud slime. The remainder stuff to the stamps, pyrites, &c. The fin sec. yields by dry assay 70.50 per cent. pig lead. The muddy ore (bourbes) 25 to 30 per cent. Stamp stuff 15 to 20 per cent. These results lead to the belief that the loss in metallic matter is very considerable in the treatment of ore as rich as that in the criblery. It is unquestionable that we gain very much by pursuing the breaking and sorting of the ore even of the cribles. Of the stamp ore, some samples have yielded us in the dry way 25 to 30 per cent. of pig lead; in admitting a more feeble standard, we think one can draw from the ore a higher proportion of crible stuff. Even here the amount has been only 3-100ths of the whole weight of the ores treated. (To be Continued.) ART. II. THE IRON MANUFACTURE OF GREAT BRITAIN- (Continued from page 140, Vol. 7.) By Wм. SECTION IX-THE QUALITY AND FUSIBILITY OF THE CRUDE IRON DEPENDENT ON THE STRUCTURE OF THE ORE.. THE very different action of the various ores of iron in the same furnace, under similar conditions of fuel and flux, as shown by their less or greater fusibility, and the degree of carbonization of the resulting metal, is a subject of paramount importance to the iron smelter. Having witnessed the reduction of large quantities of ores of nearly every description, and noted the peculiarities bearing on the fusibility of the ore, and quality and fusibility of the resulting crude iron, presented by each in the blast furnace, we have concluded that the quality, measured by the quantity of carbon in combination, is directly dependent on the structural arrangement of the ore; and that the fusibility is dependent on similar causes, being greater or less according to the percentage of carbon combined. It is known to intelligent smelters that in its descent in the blast furnace, the ore is deoxidated-the oxygen of the oxide of iron combining with gaseous carbon forming carbonic acid. In its further descent, the deoxidized metal combines with a greater |