The records of the rain-fall of the State differ greatly in various localities, depending on the topography of the country. In San Francisco and in the coast counties it appears to be about twenty per cent. more than in the great valleys of the Sacramento and San Joaquin. In Nevada City, at an elevation of about 2,500 feet above sea-level, the fall of rain has been more than double that of the valleys. Higher up in the Sierras deep snows fall, which do not melt until late in the summer, when they furnish in a wet year the supplies of water necessary to hydraulic operations and quartz mining.

It will be observed that during the past three years (1868, '69, '70,) the aggregate rain-fall has been only 38.68 inches, which is but little more than that of many single years, and much less than fell in any other three consecutive years since the settlement of California by the Americans. The consequence has been a material diminution of the gold product in the face of a greater amount of development and exploration. Hydraulic operations have been almost suspended, and even the quartz-mills have been obliged to shut down or run at half their capacity for want of water.

The present season, however, has opened auspiciously, and promises to equal our best years in the supply of water. The rain-fall for the first three months of the season, up to end of December, has reached 12.02 inches at Sacramento. It is now believed the fall for the season, October, 1871, to May, 1872, will reach thirty-six inches.

The following table prepared by Mr. F. B. Pilling, of the United States Signal Service Corps of San Francisco, will show the distribution of the rain-fall for December, 1871. It will be observed by comparison with Dr. Logan's table, that rain-fall at San Francisco was 3.77 inches in excess of that of Sacramento for same period.

Table showing daily and monthly mean of barometer and thermometer, and amount of rain-fall for the month of December, 1871.

Mining inventions and improvements.-The past year has not been noted for the introduction of many new or important appliances useful to the mining industry, but several inventions have been brought to a greater degree of perfection, and are now coming into more general use, with the most favorable results to economy in mining.

Hydraulic machinery.-In the gravel and hydraulic mining regions of the State, the improved pipes and nozzles for projecting a large quantity of water under great head or pressure against the gravel banks, have been thoroughly tested and found to be valuable accessories in the extensive and economical working of our auriferous deposits, and may be said to have revolutionized this branch of mining. The pipes in general use are those of Messrs. Craig and Fisher, of Nevada City, and Mr. R. Hoskins, of Dutch Flat, which are described in the report for 1871, pages 63 to 65. I doubted last year whether 1,000 inches of water could be successfully thrown through one nozzle in hydraulic mining. That doubt can no longer be entertained. The Dutch Flat Blue Gravel Company (on the Taeff ground-see my last report, p. 84) have been throwing 1,200 inches through a Hoskins pipe, with 432 feet head, and are now constructing a pipe to throw 2,000 inches. In fact, hydraulic mining is assuming proportions heretofore scarcely dreamed of.

Quartz-crushing machinery.-In quartz-mills there has been one invention which possesses the merit of novelty in the application of crushing power. This is a trip-hammer quartz-crusher, invented by Mr. J. D. Crocker, of Virginia City, Nevada, and lately introduced in California. A small five-stamp crusher was exhibited at the mechanics' fair of San Francisco in September of this year, and attracted much attention and favorable comment from persons interested in mining.

The chief improvement in this invention consists in operating light stamps on the principle of the tilt or trip-hammer, whereby quick, sharp

blows are made, with very light stamps, and with less proportionate power, according to weight of stamp and frequency of blows, than is required in operating heavy stamps with a direct lifting action. The advantage of sharp, quick blows with a light stamp, must be obvious to

every one who has employed alternately a small light hammer, and a heavy one for breaking quartz before a battery. The inventor claims a decided advantage in his 400 light blows per minute over the 50 to 60 blows per minute delivered by the usual 600-pound stamp. A 5-stamp battery of this construction strikes 2,000 blows per minute; and while the first cost is greatly reduced in attaining the same crushing capacity, the power required to run it is also much reduced. The difference in freight to many places would also be very great. The machine is made of different sizes, and calculated to crush from 7 to 35 tons per twentyfour hours, according to size.

Whatever may be the results of its practical working on a large scale, there can be no doubt that it will prove an invaluable invention on account of its lightness, portability, and low price, to those who are engaged in the experimental development of quartz claims in localities where custom mills do not exist.

The capacity of the most powerful mills in California for crushing quartz is from ore to one and three-quarter tons per day (24 hours) to each stamp-the usual weight of stamp being from 600 to 700 pounds, and the drops 60 to 90 per minute. While this method is acknowl edged to be slow, it is not probable that it will be superseded for many years, if at all; but in the mean time attention is being attracted to all inventions which claim to work greater amounts of quartz in a given time and at less expense for cost of machinery. Of this character is an invention of Mr. T. R. Wilson, known as "Wilson's Steam Stamp." The principle on which this mill operates is that of the direct application of steam to the stamp, the stem acting as a piston. The best results have been obtained with 70 pounds of steam and 206 drops per minute for each stamp. The average amount of ore which it is claimed can be crushed in a day (of 24 hours) is 23 tons with a No. 6 slot screen, and the average consumption of fuel is about one cord of wood to 10 tons of ore. As instances of its capacity we are informed that some time since 10 tons and 800 pounds of rock were crushed in eight hours and forty-five minutes, using only one cord of oak wood. Again, in one run 51 tons were crushed in forty-seven hours, and 10,800 pounds in four hours fifty minutes with 68 pounds of steam. Several of Mr. Wilson's batteries are now in operation in San Diego County where they seem to meet with favor. A detailed description of this invention was given in the Mining Commissioner's Report for 1870, page 668, and it is briefly referred to here as one of the improvements apparently coming into more general use.

Not a year passes without the invention and introduction of numerous devices for the saving of fine gold and quicksilver in the tailings of our quartz-mills. These rarely achieve any reputation outside of the district in which they are invented, and many, after months of experiment and trial, are rejected as useless. One of these undercurrent sluices, invented by Mr. Evans, and lately improved by Dr. Frey of Sacramento, is made of cast iron, with transverse corrugations on the bottom, semicircular in shape, and three inches deep. At the bottom of each alternate corrugation is a narrow slit through which the heavier material falls down into another riffle below with larger corrugations. Both riffles are set on the same grade, which should be about one foot in twelve. The lower box is charged with quicksilver. These sluices do not cake, nor do they require any attention beyond cleaning up once a week. They have stood the test of use in quartz-mills below all the contrivances for saving gold, and have made large returns of gold, H. Ex. 211- -3

silver, concentrated sulphurets, and quicksilver, that would otherwise have been lost.

The following is an assay of tailings saved at the Rhode Island Mills, Nevada, by these sluices during a run of one week:

Gold, $75.24; silver, $76.96; quicksilver, 250 pounds to the ton. One of the most important appliances in the economical running of quartz-mills is Stanford's Self-Feeding Apparatus, which is rapidly gaining favor with miners and millmen. This consists of a hoppershaped box placed above and in front of each battery. The feed-shovel åt the bottom of the box is connected with a lever and a rod, and is shaken at each blow of the middle stamp of the battery by means of au upper tappet which strikes upon one arm of the lever. By this means motion is communicated to the forward end of the feed-box. One man can attend to twenty stamps, and the feeding is more regular than by hand, and materially increases the crushing capacity of the mill.*

Cement and gravel mining by machinery.-The process of treating hard cement and gravel by grinding and friction, instead of crushing under stamps, was introduced several years since by Captain J. B. Cox, who invented for this purpose the machine known as the "Cox Pan." This invention was intended to supersede the use of stamp-mills, by which method the bowlders, rarely containing gold, were necessarily crushed under the stamps at a great waste of time and power. This invention was not for a time received with favor, and in some cases was rejected after trial; but recent practical workings with the machine, since some improvements have been made, and after some changes in the manner of feeding, have demonstrated its utility and economy in the working of hard-cemented gravel. This pan is about five feet in diameter and two feet in height, and is intended to hold a charge of half a ton, or from 1,000 to 1,200 pounds. The rim of the pan is made of boiler-iron, and it has a perforated cast-iron bottom, through which the finer saud and auriferous material fall into the sluice-boxes or other gold saving appliances. The bowlders and large pebbles, which constitute so large a pro

*On the other hand, some of the most experienced millmen in California prefer feeding the batteries by hand to any form of automatic apparatus. The self-feeders, they say, may be superior to careless or unfaithful workmen; but a skillful feeder can, if he chooses, by giving to each stamp at exactly the right instant exactly the amount of rock it requires, increase the capacity of the battery to an extent which more than compensates for the extra outlay in wages.-R. W. R.

portion of the cemented gravel, are discharged at intervals through a section of the bottom of the pan, which is opened like a trap-door, by means of a lever, when they have accumulated to such an extent as to retard the grinding and pulverizing of the cement in the pan. Four revolvingarms are attached to a shaft which passes perpendicularly through the center of the pan. On these arms are fastened the steel teeth (in appearance like plowshares) which, in the rapid revolution of the arms, break up the cemented gravel. An abundant supply of water is dis tributed while the pan is in motion, and materially aids in the disintegration of the gravel. Better results are claimed when the pan is fed continuously instead of by charges, which was the practice on its introduction. Details of the workings of this process will be found in the present report, in the matter descriptive of gravel operations near Jamestown, Tuolumne County, and at Dutch Flat, Placer County.

Device for transportation of ore in mountainous regions.-Mineral countries are nearly always mountainous, and the transportation of ores from the mine to au available mill-site or location for a furnace frequently requires a large outlay of money in the construction of a wagon-road or tramway, and a consequent expense in the hauling and transportation of ores, which prevent the profitable working of mines so situated. In order to obviate this difficulty, Mr. A. S. Hallidie, of San Francisco, has perfected an invention which he terms an "Endless Wire-Rope Way," a model of which, on a practical working scale, was exhibited in the fair of the Mechanics' Institute in San Francisco, in September, 1871.

This invention is one which promises to materially facilitate the working of quartz and other lodes located at inaccessible points, or where it is difficult to transport the ores from the ledge to the mill. It can be used at such locations for the delivery of material or ores in mountainous places or deep gorges; from the shore to vessels in the offing; for working up hill and down, and, where there is much descent, for economizing the power thus obtained by gravitation for any desired purpose. The invention consists in the use of endless iron or steel wire ropes, supported on peculiar sheaves, placed on posts, actuated by the gravity of the descending loads, or by an engine attached to a grippulley. The function of the grip-pulleys is to hold the rope so as to prevent its slipping in the groove. In general, the difference in altitude between the mill and the mine is sufficient to obtain by gravitation quite an amount of power, which is transmitted by the grip pulleys for whatever purpose it is required, (and where there is no power obtained in this manner, it is given by a steam-engine.) The receptacles are small, self-dumping boxes which contain from 50 to 150 pounds of ore or other material. The rope travels two hundred feet per minute; the posts with the bearing pulleys on are usually two hundred feet apart, the hooks holding the ore-sacks being placed about fifty feet apart, and holding one hundred and fifty pounds of ore each. The rope is actuated by steam or water power whenever there is not sufficient descent to run it by the gravitation of the descending loaded carriers. In any event it is better to connect with the motive-power by gear, so as to secure uniformity of speed. The amount of ore delivered being four sacks of one hundred and fifty pounds, making six hundred pounds per minute, or 36,000 pounds per hour, or one hundred and eighty tons per day of ten hours. This can be increased or diminished at will. The cost of delivering the ore, including wear and tear of machinery, interest on outlay, and running expense, is about twenty-five cents per ton per mile. The cost of constructing such a line is from $4,500 to $7,000 per mile, according to the topography of the country. By its use material