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.

The system has a great advantage where water is scarce, as the capacity of machinery may be rated according to the amount of water for power. Mill-owners having their own ideas as to what machinery is best suited to their wants and circumstances, and as some may desire single portions which make up the process as a whole, to accommo

*This description is not sufficiently definite to permit a discussion. The theoretical explanations are partly unintelligible and partly untenable. The production of very fine bullion is not of itself a proof of thorough extraction, but rather an indication to the contrary, particularly in silver ores. I am inclined to ascribe any practical success which the process may have achieved, to the fine dry crushing, the use of chemicals, and the large quantity of mercury continually employed. But all millmen know that these methods have their drawbacks, in cost, inconvenience, and other respects. I have never seen a thorough discussion of the economical results of this process; and though I am prepared to believe that it may be advantageous, under certain circumstances, the claims in its behalf, that it involves some novel electrical action, and that it works equally well for all ores, no matter what base metals they contain, are undoubtedly without foundation.-R.” W. R.

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 chamber 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 car

bonized 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,

as can be seen, it will descend to the fire as it is needed. The cylinder is worked by friction gearing.*

Rock-drilling machines.-This class of inventions was introduced in California in 1870, and is now extensively used in this and adjoining States and Territories. The only machines of this description in use in California are the diamond drill (Leschot's patent, as improved by Severance & Holt) and the Blatchley drill, invented by Dr. Blatchley, of San Francisco, the Burleigh drill used in the eastern States and in Colorado never having been introduced here. To the successful operation of these drills we are in a great measure indebted for the recent investment of capital in and consequent development of our great mineral resources. By the use of these machines bed-rock tunnels can be run in from one-half to one-sixth of the time required by hand-drilling, so that one of the greatest objections to this kind of mining (the great length of time required to drive a long tunnel) is obviated. All over the Pacific coast are innumerable mines that will almost pay for working by the ordinary method, which, by the use of these drills, can be made to yield a large profit. A cheap, simple, durable, and efficient rock-drill, whereby the power of fifty or oue hundred men can be concentrated in driving one drift or tunnel, has long been a desideratum, and has long exercised the ingenuity of our mechanics and miners. The system of drilling by machinery used in the construction of large tunnels, such as the Hoosac and the Mount Cenis, was not adapted to our mining tunnels, which are rarely more than 6 by 4 feet in dimensions. The great difficulty was in the application of power. Steam was tried, but the pipes conveying steam to the drills at the face of the tunnel created an unbearable heat in the tunnels, and this plan was abandoned. Compressed air was next tried, with better results, but the construction of compressors involved a great additional expense, which neutralized the utility of drilling by power. We have reason to believe that all obstacles have now been overcome by the use of water under pressure as a motive power.

The diamond drill.-A. J. Severance, after two years of constant labor and experiments in building and running the diamond drill in tunnels and open-cut rock-work, has at last brought this drill to a high state of perfection. He has been engaged in running some of our hardest bedrock tunnels, and has proved by actual demonstration that he has run the same tunnel many hundred feet with one of his improved drills at a cost of $30 per foot, the same tunnel costing by hand-labor $46 per foot, besides running twice the number of feet per month as was run by hand. By recent improvements his drills can be placed at any angle and adjusted so as to be able to bore holes in any desired direction as easily as by hand-drilling; and during the last 400 feet run in a tunnel 62 by 91, not a hole was drilled by hand-labor. Heretofore these drills have been run by compressed air, or by steam power; but recent modifications have been made by him doing away with the great cost of an air-compressor or steam-power, and in its place the application of waterpower has superseded steam or air. This has been accomplished by attaching an ordinary hurdy-gurdy wheel or a small turbine upon the *There is no feature in this furnace which can fairly be called new, taken by itself. E is an ordinary gas-generator; the introduction of air to the carbonic oxide from the generator is necessarily involved in the use of the latter; and the use of the cylinder is equally familiar. Novelty may, however, be claimed for this combination of well-known contrivances. But it is open to another objection, which concerns me more than any question of novelty. It is an arrangement for procuring a blow-pipe heat when no such heat is required, indeed, for a process (namely, that of roasting) to which such a heat is fatal.--R. W. R.

back end of the car, upon the front end of which the drills are firmly secured. The drill-car is made to suit the same track as the rock-car, and when eight to twelve holes are bored the drill is disconnected by detaching the feed-hose, (rubber or canvas, three inches in diameter,) which simply connects the water-pipe to the nozzle, which plays upon the water-wheel, and is geared to the drills upon the front end of the car. The car is then run back to a chamber in the tunnel, the holes loaded and filled, or exploded with a battery simultaneously, thus util izing the whole force of the powder. As many as 663 cubic feet of loose rock have been obtained by a single shot of twelve holes in a tunnel 63 by 9 feet. This new method of using water-power in the tunnel has completely satisfied the miners that the year 1871 has been a year of progression in mining, and that the day is now close at hand when their tunnels can be run much cheaper and at a great saving of time, most of the mines having already hydraulic pressure by means of ditches, affording them plenty of water. The amount of water required depends upon the head obtained. For a two-drill machine, under 300 foot head, about ten to fifteen miners' inches is sufficient; but the more head the less water is required. The water may be taken from the ditch at any distance from the drill, and conveyed down to the mouth of and up the tunnel to the drill at the face of the tunnel, and it may be conducted through a 4 or 6-inch pipe, made of No. 10 to 24 iron, according to the amount of pressure at hand. Two machines just sold to the Union and American Companies in Nevada County are being run under 300-foot pressure. Where there is no natural head of water, one can easily be created by means of Knowles's patent steam-pump, which can be placed at the mouth of the tunnel and supplied with water by means of a small reservoir, thus pumping the water up the tunnel through a pipe against the wheel, the water thus running back into the reservoir, and being pumped over and over again without exhausting the supply. A trial was made recently at the Miners' Foundery in San Francisco for the benefit of mining and scientific men. The pump used was a small-sized Knowles pump, steam-cylinder 10 inches, water-cylinder 5 inches; pressure raised upon the pump 70 pounds-equal to about 150 feet of waterhead; and two drills were run at the same time through hard granite, boring a 1 inch hole at the rate of one inch per minute. Mr. Sutro, of the Sutro tunnel, with his engineer, witnessed the workings of the drill, and at once purchased one for his tunnel, which no doubt will save at least three-fourths of the time required over hand labor. This new application has overcome all doubts and difficulties in the way; tunnels are being run which for years have been abandoned, and new ones are started.

The Diamond drill is now in use in tunnel operations at Smartsville, Yuba County; the Union Gravel Company's ground, Nevada County; the American Company's ground, North San Juan; Nevada County, Oregon City, Butte County; the Taeff and Franklin ground, Dutch Flat, Placer County, and in many other localities in perpendicular boring for prospecting purposes, or in boring for water. Some details of its operations in running tunnels will be found in this report, where operations at Smartsville, Yuba County, are described.

During the publication of this report a novel and important application of the Diamond drill has been successfully made at Saint Clair, Pennsylvania, in the sinking of deep shafts. This will be fully described in my next report; in this place I can only say that the peculiarity of the method consists in boring a large number of holes from the surface to the full depth of the proposed shaft, unless this is too great. Three