can be transported from a higher to a lower, or from a lower to a higher point. In the last case, power must be applied, which can be done directly from a stationary engine at one'end by means of the grip-pulley; in the first case, often no extra power will be needed, the gravity of the descending loads being sufficient to keep the rope in motion. Similar inventions have been made before, and the merit of this, therefore, depends on the peculiar construction and adaptation to the wants of the localities. One can readily see the great many advantages that this method possesses, from the fact that it requires neither road to be built nor expensive machinery; that it can be run at all seasons of the year, even when there are five or eight feet of snow on the ground; that it can be rapidly and cheaply constructed in the worst possible country; and that when there is sufficient grade, not only does it run itself by gravitation, but produces a motive power at both ends of the line. Running at four miles per hour, the boxes are carried down at one side of the posts and up the other, 400 to the mile, each delivering fifty. pounds of ore, or ten tons per hour, and they can be run twenty-four hours per day.*

Paul's process. The "electric dry amalgamating process," introduced by Mr. Almarin B. Paul, of San Francisco, has been tested in a number of localities within the past two years; and though the reports of its value vary, it is but fair to say that the inventor has received many sertificates of a very positive and favorable character.f

*This device is more fully described in a separate chapter of the present report, q. v. + The latest in date of these is given herewith:

DUN GLEN, NEVADA, March, 1872.

Mr. ALMARIN B. PAUL-SIR: Yours asking for statement of tests made at Sprague & Co.'s new mill at this place is received, and we here cheerfully comply as follows: We reduced 22 tons of ore from the Auburn mine, owned by Messrs. Wright & Wentworth, containing besides gold and silver, magnetic iron, carbonate oxide, and sulphuret of lead, and has always been considered of a very refractory nature. The 22 tons worked by your process paid $107 per ton. Eleven tons of same ore worked in pans paid $53 per ton. The bullion from your process runs as high as 989-1,000 fine.

We also worked the tailings of a lot of 20 tons of ore from the Monroe mine, which ore in the first instance was reduced by battery and pan process, at Essex Mill, and paid $8.14 per ton. The tailings from this lot yielded by your process $293.27. The bullion per battery and pan working was 584 fine; by your process, as per certificates of San Francisco Assaying and Refining Works, was 960 fine. The loss of mercury was less than half a pound per ton.

We also made a test on a small lot of iron sulphurets from Monroe mine, very closely concentrated, and which had been previously worked by battery and pan amalgamation, and which had been salted, oxidized, and worked several times previously--each time yielding some low-grade bullion. This lot was treated by your process, and to our astonishinent obtained more metal in value than we had gained by all the several previous working, though very carefully done. The bullion by last working, as per certificate of California Assay office, was 999-1,000 fine.

We have now commenced on the "Lang Syne" ore, from a mine belonging to the "Great Central Mining Company of San Francisco," the results of which speak more for your process, and the great revolution the system is likely to inaugurate, and of its inestimable value, than any tests we can give you. That you may fully understand this we must particularize.

In 1863-'4-'5, the Lang Syne mine was worked, and in 1864 a mill erected for reduction of its ores, and over $100,000 expended and lost. The ore could not be made to pay.

The operation was pronounced a failure, and the mill removed. Tests of ten and twenty tons were also worked at the Essex Mill, having all the then modern improvements, with like unsatisfactory results. The mill just erected for the working of your process is built upon the same spot where the old mill stood. We have now worked a number of tons of a class of ore of which there are hundreds of tons in sight, with the result of $30 per ton and bullion 966 fine, being more than double the result obtained in the other mills.

The same renewed life which this locality has received through the introduction of The process and machinery are described in Mr. Paul's circular as follows:

I start out with the idea, speaking only of mill ores, that the precious metals, in bulk of value, are in the most simple but delicate conditions, and require thoroughness in reduction, care, and chemical affinities, to unlock. That in their metallic state they are incased in their matrix in atoms so minute that the word "infinitesimal" hardly expresses the fineness. To meet these conditions it requires thorough pulverization, then delicacy in preparation, amalgamation, and precipitation. You will understand by this that as far as gold ores go-excepting the advantages of calcination-I regard desulphurization, with all its appliances, as an unprofitable expenditure of time and money, and often complicating nature's simplicity. I would further add that chlorination is only an expensive mode of getting a high percentage of gold, which can be obtained by the perfect working of this system; at less than half the expense.

In all ores are gaseous and refractory substances, atmospheric or other films, which coat the metal and create repulsion between it and the mercury. An increase of these repulsive elements takes place where the grinding of ore, iron, and mercury are carried on together. There is sufficient evidence to establish this point-every intelligent miner has experienced it. I must, however, for the less experienced, quote from one in high authority, (Overman, p. 280:) "All metals appear to have a tendency to float in water, when in fine particles, some more than others. This is caused by a particle of gas, either air or water gas, adhering to the particles of metals, which causes it to be light and float. Precious metals appear to possess more of this quality than others."

Again, the same author says: "Gold is by far heavier than silex, but we may observe, by means of a microscope, a multitude of fine particles of gold suspended in water, when we cannot detect the slightest particle of silicious matter." To sum up, as has been well expressed by another: "We have too long attempted to do by brute force what must be done with care and the gentle persuasion of affinities."

The practical working of the process is as follows: The ore is first heated, dried, then reduced dry by such machinery as best suits the views of parties and accomplishes the object of bringing the ore to the fineness of No. 14 wire cloth. The crushed ore is then conveyed to an iron pulverizing, preparing, and self-discharging barrel, where it is pulverized to flour in fineness and prepared for amalgamation, under heat. By heat, friction, and chemicals, it is put in what is termed an infinitesimal, electrical, live, and pure condition. Thus there is a combustion of all gases, destruction of rebellious films, and expulsion of atmospheric dampness, instead of which are created the greatest activity, attraction, and cohesion between the precious metals only and the mercury.

The ore thus prepared being so fine and light, and the metal to be operated upon infinitesimal, the question now comes how to produce effectual contact for amalgamation. To meet this point the ore is conveyed in its dry, heated, prepared, and electrical condition to an iron, wood, or earthen cylinder, to which is added from 20 to 25 per cent. in weight of mercury. The condition of the ore raises the temperature of the mercury, lessens its density, increases its volume, and the result is, the ore and mercury play together like water, and create the most thorough and complete intermingling. So perfect is the blending, that on examination with the naked eye hardly a particle of mercury is disclosed, notwithstanding the percentage to ore is so large. The mercury, in this finely-divided state, having been in continuous motion, rolling over and over on the surface and through the entire mass during the one hour given for amalgamation, it is reasonable to suppose has effectually done its work, and that the precious metals, no matter how fine, cannot escape a contact in this searching.

The harmony created between precious metals and mercury is finely illustrated by the fact that the baser metals are placed in antagonism, and consequently leave the mercury free from the fouling or sickening properties of the ore, no matter what it contains. It will be observed, too, that every infinitesimal particle has had its weight

your radically improved system, we are certain can be extended to others similarly situated by the introduction of your mills.

We will add that we have no difficulty in saving the mercury, and assert that the loss on all ores can be brought within that of pan amalgamation, and ordinarily very considerably less. Under all circumstances it is bright, active, and pure, and is used over and over again without any cleausing or retorting.

Your self-feeding and self-discharging pulverizing barrel is, without exception, one of the most complete reducers that we have ever seen. Its capacity is fully equal to your estimates of it, receiving ore from No. 14 wire cloth.

The pulverizing of ore by quartz, instead of iron, is not only cheaper but much better. If desirable, we will, at any time, give results of our working.

Yours,

SPRAGUE & CO. CHARLES D. SMYTH, Superintendent of Sprague & Co.'s Mill, also Great Central M. Co.'s Mincs.

increased by contact with mercury, besides being placed in a state to receive, more actively, the precipitating element.

The operation, it will be admitted, is so far perfectly done, and the next question is the separating of this mingled mass. To accomplish this, the ore from the amalgamating barrel is discharged into a large wooden settler, of especial construction, and where water for the first time is introduced. The greater portion of mercury, carrying the precious metals, is soon precipitated and collected for drawing off into a receiver. The lighter portions of mercury and metal, in due time are drawn off into an electric settler, where they are precipitated by electricity upon the principle of electro-plating, excepting there is no adherence of metal or mercury, both of which are drawn off together. The residue is then allowed to flow off as wastage, or, if desired, for concentration of base metals. A one-thousand-pound charge is worked every hour, and yet every one-thousand-pound charge has over four hours of varied treatment.

It will be observed that though considerable mercury is used, it does not involve having so large an amount on hand as at first thought would seem, in consequence of its being in continuous use.

There are other essential points of equally practical character, but which are only given to those who engage in working the process.*

COST, WEIGHT, AND EXPENSE OF WORKING.-By way of giving definite data as to expense of machinery, I will contract to furnish in San Francisco, until further notice, all material (outside of power and timber) requisite for working according, and up to my idea, which embraces crushers, pulverizing, preparing, and amalgamating barrels, electric settlers, concentrators, shafting, gearing, pulleys, belts, boxes, bolts, copper, zinc, conveyers, and bolters, as follows:

Royalty is included in the above figures. Or parties can have the machinery built on my order and after my plans, at such founderies as best suit their business and local relations, by allowing my charges for patents, which are set at low figures, as the above estimates show.

By way of further insight, I give the following as a close though approximate estimate of weight, power, cost per ton of working. Of course these figures vary according to locality, wood, and labor:

The putting up of machinery is not expensive, it being mainly framing timber. I offer no objections to stamp batteries; on the contrary, for larger mills the additional cost has an equivalent for work executed for pulverizers.

Stamping machinery of mills already erected can at a small expense be changed to answer my purpose as reducers.

The principal objection heretofore urged against dry working is dust. This I have overcome by using incased batteries or crushing-machines, then pulverizing ore in incased barrels, which are both self-feeding and self-discharging. From this barrel the ore is conveyed mechanically and deposited in another-the amalgamating barrelwhich is closed during the operation of amalgamating. From this it is delivered into a closed hopper, and from thence gradually into settlers, all being performed with an ease and cleanliness not found in any mode of working.

date these views, I will sell separately electric settlers singly or in pairs, (as they should properly go.) These settlers precipitate flour mercury and metal, by the agency of electricity, and at any time within ten minutes can be cleaned up quite thoroughly without stopping machinery. The action of electricity has a remarkable cleansing effect upon mercury. Their efficiency in this respect is such that where ores contain sickening properties, they will soon pay for themselves. They are also admirably adapted for working slums from mills; and for gathering the flour mercury therein they are superior to anything ever introduced.

The self-feeding and self-discharging pulverizing barrel is another desirable article. It is well understood by quartz miners, that down to a certain size, stamps or crushers are the most efficient reducers; but for reduction to a powder at a practical expense, great difficulty has been experienced, on account of slowness and large power required. In these barrels these defects are remedied in consequence of making it both selffeeding and self-discharging.

It takes but little power, comparatively, from the fact that but little ore is required at a time, it going in at the ratio at which it is discharged.

Again, on account of there being a less amount of ore at a time for reduction, a less amount of reducing iron is required. Again, more work is executed at less expense, from the fact that ore, as soon as reduced to its given fineness, is out of the way, leaving no idle work to be done. This barrel can be made of any size to work from one ton to twenty tons per day, and to reduce to any given fineness from No. 20 wire-cloth to 100. It is made for strength and work, and will reduce faster, cheaper, and with less expense for wear and tear, than any class of pulverizing-machinery. In fact I am convinced that where power is no expense, the cheapest way of reducing quartz below a given fineness is by attrition, and making quartz reduce quartz, in these self-feeding and self-discharging pulverizing barrels.

This system is secured by four letters-patent, issued June 29, 1869; October 19, 1869; April 5, 1870; May 10, 1870.

Ambler's blow-pipe furnace. This apparatus was patented during the year by Mr. Stephen S. Ambler, of Monitor, Alpine County, California. It has not yet been successfully put in practice, though several furnaces of the kind are reported as in course of construction in California and Nevada. The following description is taken substantially from the Scientific Press of San Francisco.

The main principle in this furnace, which differs from those of ordinary construction, is that a stream of heated air is passed into the ore without any loss of oxygen by combustion, and that the wood is converted into charcoal before it reaches the fires, to be used as fuel. These are two important points. Generally when air is introduced it passes through the fire, thereby losing a large proportion of its oxygen; by the use of this furnace all of it is utilized, from the fact that it is merely heated, not burned. This excess of oxygen prevents concentration or melting of the sulphurets in the cylinder, another point of great importance. When the ore contains a large proportion of sulphurets, the heated air may be passed over it by means of the blower and pipe and they may become more completely oxidized, whereas if only a small proportion of sulphurets are present, the air can, by means of the dampers, be turned under the grate into the fire. These draught can be regulated at will to throw either all or a certain portion of the air in the direction required, either into the fire or the revolving cylinder containing the ore, according to the class of ore under treatment. The hot-air ehamber is arranged so as to permit the introduction of a jet of steam, or of water which is instantly converted into steam, and aid in the decomposition of certain classes of ores.

In order to explain this more fully, reference is made to the accompanying cuts, of which Fig. 1 is a side elevation, and Fig. 2 a plan.

A, represents the furnace, constructed of brick in the usual manner which is provided with a grate over the lower door, and above which is the carbonizing chamber, E. This chamber is kept constantly filled with wood which is fed through the upper door, C. When the doors, C and D, are closed, the wood in the upper part will be carbonized or converted into charcoal, and, as the fire below burns out, the charred or carbonized wood will settle down and continually feed the fire. At the back of the chamber, E, is a hot-air chamber, F, into which the heat, gases, and flame from the chamber, E, and also steam,

when desirable, pass through the flue, g. A blast pipe, h, enters the chamber, F, at about an equal height with the flue, g, while a branchpipe, i, passes to the front and enters the chamber, E, so as to deliver its blast directly under the fire in the grate. The blasts from these pipes are regulated by dampers, j, j'. When the damper of the pipe, h, is closed, and the damper, j', opened, the blast will be delivered upon the grate, and a reducing flame produced which will pass through the flue, g, into the chamber, F, and when the damper, j, is opened, oxygen will be supplied to the revolving cylinder, K, which contains the ore, through the chamber, F, and an oxidizing heat produced. In communication with the chamber, F, opposite the blast-pipe, h, is the revolving cylinder, K, into which the ore is fed through the hopper, L, so that as the ore meets the blast and heat from the chamber, F, it will be carried into the revolving cylinder, and there subjected to heat and roasted while passing through. In connection with the furnace, A, and revolving cylinder, K, is the dust-chamber, B. The heavy ore passes from the cylinder, K, into this chamber, and is taken away from the doors below. The light dust is carried by the current of air against the revolving perforated disks in O, one-half of which are submerged in water. These disks permit the passage of air, but the wet surfaces catch the 'dust, which, by the revolution, is carried under the water and washed off into the vat below, where it can be taken out when required.

The process of feeding the wood into the closed chamber, where it may be subjected to heat without air, is an important improvement, and,