Volume 35 (1877) (426 pages)

October 20, 1877.] MINING AND SCIENTIFIC PRESS 249 HYDRAULIC MINING IN CALIFORNIA.* No. [By Avo. J. Bowie, Jr, A. B., Mining Engineer. ] Investigation of the Comparative Values of the Ditferent Gravel Strata at North Bloomfield. With their experience of the past and considering the contingencies of proposed explora. tions, and the attcndaut costs of au enterprise which had for its ultimate aim the workiug of the entire auriferons deposit, after mature deliheratien it was (a3 a preliminary step) deemed of paramount necessity to ascertain, as far as practicable, the relative values of the ditlerent strata of the gold-bearing alluvia, so that they might judge to what extent tho prospects would justify their expenditures. <A serics of explorations were subscquently carried out under the immediate supervision of their able cnginccr, Mr. Hamilton Smith, Jr., and the result of his investigation is best given in his own words: “To test the comparativo valucs of ground . developed hy the shaft workings and top gravel, 240 samples, weighing in all two and one-half tons, were taken at even distances from the sides of the drifts, and the same quantity sampled from different layers of the upper hank. These samples were carcfully panned ont, and yielded, the blue $1.10 per ton, the white a largo number of colors, but an inconsiderable weight of gold. Tho gold from the blue dirt was from 50 to 100 times heavier than that from the white gravel.”"+ Although the gross yield from this sampling of the npper gravel was slight, it is anoteworthy fact thatin each of the 240 pans one or more colors of gold were found. Comparative Value of Gravel Strata In Stanislane County. At the Light elaim, Patricksville, a comparative test of top and bottom gravel was made. 58,340 cubic yards top gravely yielded two cents per cuhic yard. The hottom gravel§ (four feet deep) was then washed up, when it was discovered that this ground had been extensively drifted; but notwithstanding this fact, 4,966 euhie yards yielded 55 eents per cubic yard. A trial of top dirt was also made at the Light elaim, La Grange; 41,038 cubic yards top dirti yielded three cents per cubic yard, aud 7,242 eubic yards of bottom dirt** yielded 94 ceuts per eubie yard. Sand Strata. In the gold-bearing drift of the Sicrra Nevada, layers consisting exclusively of wash sand are generally found to contain very little if any of the precious metal{t. In guich miuing it sometimes happens that from the positiou of the bedrock the detrital accunmlations assume the form of reclining cones, the apex repesing pon the top of tho hill, Where such is the ease, the bulk of the gold is concentrated in the lower end of the deposit. These gulches are frequently found to be exceedingly rich. : It is not within the scope of this paper to discuss the origin of auriferous detritus, or in any way to account for the mode of occurrence of gold, but these general facts are merely cited as an explanatory outline of the subject, and to show the reason why a system of sluicing is adopted which bottoms the entire deposit. The Records of Gold Washing. The early record of gold washing extends to the days of the Greeks and Romans. History has famiharized ns with the wonders of the Pactolus and Tagus, and it is a fact§§ that the diggings north of Aquitania produced in two months such a large amount of gold that its price fell 33% throughout the whole of Italy. Gradually, one after the other, the well-known deposits of the Old World have heen exhausted. The alluvia in Siheria, however, kept alive the interest in gold washing, and the subsequent discoveries in California and Australia infused a new life into this kind of mining. Since that time gold washing has been carried ou in different parts of the world on a most extensive scale, hut the application of water under great pressure to ‘‘gold placer mining” is au outgrowth of the present century. lis use is chiefly confiued to the Pacific coast, and consequontly the contributions to miuing literature relative to its application have not been numerous, Hydraulic Mining. It was left to the untiring iugeunity of the Califoruia miner in his battles for fortnne to devise the economical methods of hydraulic Mining, by which mountains of auriferous gravel are removed through the agency of a continuous stream of water, extracting the recious metals stored away by nature, and adfine millions of hidden wealth to the treasures of the world. Independeut of the financial importance of this most modern method of mining, its effects, from the gigantie scale with which itis now carried on, upon the system of drainage of the *A paper read before the American Institute of Mining Engineers of the Wilkes-Barre meeting, May, 1877. tfhe North Bloomsield Gravel Mining Co. Report by H. Smith, Jr., pp. 17-18. $$1,200. 482,775.07, ground two-thirds drifted out. $1,500. 984,709.72. _—" }tFrom Whisky Run te Coquille river, Oregon, the beach sands, formerly very rich, have becn extensively worked for tbree or four miles along the sea-coast. The produetive stratum wasa layer of black sand, onc to twe feet thick, buried from two to five feet below lighter sands. The gold eecurs in minute particles, This sand likewise contained tome platinum and iridosmine.—Zzt. Trans. Cal. Acad. Sciences, W. A. Goodyear, of the State Geo. Survey. §§Strabo, book iv., chap. vi., sec. 12. Foot-note Siuria, p. 4d, couutry as wellas the navigation of rivers, will, sooner or later, bring it iu direct conflict with agricultural and vomniercial iuterests. Apart from the constructiou of ditches and tunnels necessary for the hydraulie washing of the gold-bearing drift, cugmeers, as a rule, have had but little to do with tho suhscquent working of this class of mines. The primitive placer mining of 1853 to 1865 has passed into history. Forty-inch wrought-iron pipes have heen substituted for canvas hose aud stoye-pipes, and with the replacing of ene-inch streams by uineinch diameter nozzles, discharging under 400 feet pressure, the last remuant of the Argonauts * method disappeare 1, and hydraulic mining, With ono gigantic stride, has become an op. eration of sueh inagnitude as to require the aid of science, The Definition of Hydraulic Mining. Hydraulic mining may he detined as the art of extracting gold fromm gold-hearing detritus, i. ¢., surface deposits, placers or washings, by means of water under great pressure discharged through pipes against the aurifcrous imaterial. In working these golt deposits by this method, it is essential to success that there shonld be: first, economical msnagemeut; secoud, ample facilities for grade and dump; third, asuflicient head and an abundant supply of cheap water, As regards the ‘‘economical mnanagement,” the same can be considered a sine qua non for suecess in all enterprises, but it is especially requisite here. as the value of this kiud of miniug is based on the great facility with The Worcester Self-Feeding Drill. which profitahle results can be readily obtained, at trifling cost from washiug vast areas of ground which contain relatively, per cubic yard, insignificant amounts of precious metal, but in the aggregate, when expeditionsly and skillfully worked, give large remunerative returns, The Dump. Without the dump, hydraulic mining is an impossibility. Ou this point too much stress cannot be placed. Where thousands of cubic yards of alluvious are being daily washed from their original positions into cauyons, valleys, streams, or rivers, it is not the accumulations of a few mouths which must be considered, but places must he provided at lower elevations, where the immense hills of gravel, when “‘hydraulicked, + can be re-deposited; aud in general a very much larger superficial area for this is requisite than was originally occupied by the matorial removed, It sometimes happens in claims uear or adjoining one another, working with the sane dump and on a light grade, that tho bedrock in one is lower than that of the other. Where this occurs the claim with the highest bedrock should be the last run off, so as not to interfere with the dump of the lower claim. An illustration of this condition of affairs is afforded by the Patricksville hydrauliclelaims, in Stanislaus eounty, where three claims, one tailing over the other, are annually worked. During the last two years the lowest claim, called the Chesnau, has heen closed in the fall, its dump giviug out, whilst the upper ones continued work. With the return of spriug freshets, the canyon has been cleared of the debris, and washing has been regularly resumed in the Chesuau, continuing as loug as the dump lasted. The upper claim is closed whilst the Chesnau ‘a working, tcf:void the too rapid filling up of the creek. If the two higher claims were worked at the same time, the Chesnau would soon be closed for an indefinite period. *The name is generally applied te those pioneers whe arrived here in 1949-50. -—_ + Tho words “hydraulicked” and ‘‘hydraulicking" are the colnage of the California placer miner, and custom has here sanctioned their use, Tailing into Streams. _ It is supposed hy many that the want of dump is remedied hy discharging into a current or motutaiu rapid. This eudeubtedly would be so, were the gold placers to border on large, rapid, aud well confined streams; hutin the mountains where tho gold-bearing deposits are found, the rivers are narrow and shallow, only running water in quantity during the winter and carly spring. Seie of the annoyances and difficulties arising froin tailing into a stream can he seen on the Tuolumne river below La Grange, Tho river for 17 miles above the town has a fall approximating 1S fect to the mile. It is a large mountain stream (fed hy the snows and rains of the Sierra Nevada), well confined by ahrupt hanks. * At La Granget its width is 525 fect. Three hundred yards helow the town, opposite the Light claim, it widens te 750 feet. Bown the stream from this point the hills for the succecding three or four iniles recede, but suhsequently form prominent banks of the river. her! high water in the winter, opposite the Light claim at its greatest width, its average depth was ten fect,§ the center of the channel being 14 feet deep. When the La Grange hydraulic mining company commonced work, in 1872, the bottom of the channel was a few feet deeper. The Light claim was worked iu 1873, and hy June 23d, 1874, 720,086 cubie yards of gravel had been discharged into the stream near the claiin, and during the same period 975,064 cubic yards were dumped into the river from the Kelly and Vrench hill properties. ‘The results at the expiration of 21_ months were that the channel opposite the Light claim was filled up, the sluices were run out of grade, the river bed was shoaled on all sides, the water of a former rapid stream straggled over the accumulated debris with a hardly perceptible motion, and it is hardly necessary to add that the claim was closed. The spring freshets of 1875-76 were unusually severe, elearing the river at the claim for its entire width, and leaving a dump of over 1] feet along its west bank. ‘This spriugll (1876) work was resumed, and since then 48,280 cubic yards have been moved in the Light, aud Green’s Improved Harrow. 212,346 enbie yards from French hill, which is a quarter of a mile up stream. At present** the river is filled up nearly its eutire width to the hight of the sluices, aud the water is confined toastrip 30 feet wide discharging one foot deep over a bar. Where a small amount of tailiugs is discharged into narrow and steep canyons, winter rains and spring freshets suffice to clean them out, but where the quantity is large, in spite of the water the ravines gradually fill up, and hydraulie mining in those localities ultimately ceases. It occasionally happens that the want of dump room is obyiated hy a tunnel, and by means of it the tailings are eonveyed into large and precipitous ravines, eonsigning them to the aetion of time and water for their further remoyal, — “3 Errata.—Last issue, page 233, first column, second paragraph, fourth line, for ‘‘ western houndary” read eastern boundary, also same page, fourth column, fourth paragraph, secoud live for ‘‘ Mandango,” read Mandanga. * The river opposite the old French Hill dump is 500 feet wide. + At the ferry. The grade of the river from hore to its mouth is only a few feet to the mile. {Extreme width during high water. Width at lower sluice 700 fect. § Deeper in narrow places. . April 10th work was resumed on top dirt, ** Dry season--nionths uf August, September'and October. Evoaryptus Firz-Proor,—At the last mecting of the Academy of Scieuces Dr. Baer invited the attentiou of the Academy to a eucalyptus tree stauding in the grounds of the old German hospital, on Brannan street. The tree had passed through the fire of Augnst, 1876, and exhibited the peculiarity of resisting the action of fire—a property well nnderstood in Australia. Dr. Kellogg stated that eucalyptus shingles were in common nse in Australia, on account of their heing fire-proof. It was impossible to fire a roof made of this material. ‘There were some 132 species of eucalypti, hut all seemed te possess this nou-combustible property to some extent. Dr. Gibhon said that the planting of trees in the public strcets would he an important means of checkiug a conflagration, and as the eucalyptus seemed to be peculiarly valuahle for that purpose, and for building, the attention of the public should be called to it. Tue Continental Ore and Transportation Company have established depots at Ogden and other points of the Union Pacific and Central Pacifie railroads, and they have selected Reno as the point of supply of Nevada with coal and turpentine. An Improved Harrow. James B. Greene, of Elliott, San Joaquin county, has patented, through the Mixrxe anp Scientiric Press Patent Agency, an improved harrow, au engraving of which is shewn on thia page. The improvement consists in so eonstructing an A-shaped harrow that the bars or timhers to which the teeth are secured are hinged to a supplemental frame, and by means of connecting reds and levers, any one or more of these sets of teeth may he turncd alternately so as to relievo themselves of the rubhish which may accumulate before them aud thoreughly clean themselves. ‘The uuinber of sets of teeth may be multiplied or iucreased at will, and two er moro sets inay be united and operated by the same lever. When working ordinarily the levers will be retained by a central uctch in a curved rack, hnt wheu the harrow becomes clogged the lever controlling the frout pair of harrows is released aud turned to one side. The movemeut causes the hinged timber upon tho side to turn, so that tho teeth point hack. ward and this allows them to be wiped clean of the rubbish. Meantime, the movement of the lever around its fuleram will point the opposite set of teeth a little forward, aud they will coutiune to work until the lever is turned to the opposite side, when the relative positions of these two scts of teeth will be reversed and the opposite set will be cleaued. While this is being done the rear pair of harrows are still at work, so that there will be no portion of the ground not harrowed, and they will also serve to keep the harrow level and prevent it from pitching forward with the timbers upou the ground. After the front sect are eleaued, the lever is sct straight and the rear lever is operated so that the rear pair of harrows will undergo the same operation and become cleaned. A pair of wheels may be attached to the rear of the harrow and support a seat. The Mines and the Sutro Tunnel. A meeting of the superintendents of the Comstock miues was held in Virginia City on Tuesday. There were present: E, A. Schultz of the Bullion, Excheqner aud Justice; Judge Strother, of the Baltimore and American Flat; Chas. Foreman, of the Overman and Caledonia; N. C, Hall, of the Silver Hill; Mr. Perkins, of the Dayton; Hank Smith of the Belcher; Capt. Taylor, of the Yellow Jacket; Lon. Hamilton, of the Imperial and Alpha; Cal. Derby, of the Alta; J. L. Reqna, of the Chollar; P. Deidesheimer, of the Hale & Norcross; Cal. Gillette, of the Savage; Col. Osbiston, of the Gould & Curry aud Best & Belcher; W. H. Patten, of the Con. Virginia and California; Capt. Hardy, of the Ophir, Mexican and Union Consolidated; Chas. Bonnemont, of the Sierra Nevada; Jno. W. Mackay and Frank Thayer, of the Julia. The meeting was called to order by Mr. Requa, at half-past two. The necessity of action of some sort, with regard to the Sutro tunnel, was admitted by all, and a committee was appointed to examine iuto the question in its various bearings, inclnding the cost of the tunnel, the benefit it is likely to be to the mines, the cost of pumping water to the surface from the tunnel level, etc. The Committee is to report as soon as possible. The Committee is composed of Messrs. Schultz, Requa, Foreman, Patten and Taylor. John Mackay was called upon by the Associated Press reporter after the meeting. He said the Committee would lahor both in Virginia and iu San Francisco, and thought they would make their report in two or threo weeks. Mr. Sutro says his tunnel will havo cost $5,000,000 hy the time it shall have reached the Comstock, and he wants the mining companies to pay him interest npon that amount. The opposite party, however, claim that the eost was not over $2,000,000, aud do not favor Sutro’s proposition. This Committee is to ascertain the exact cost of pumping or draiuiug the water from the various mines of the Comstock from the level of the Sutro tunnel to the surlace, a distance of 1,650 feet, or thereabouts, also the cost of pumping up the level of the tuunel, and, in short, ascertain just what the companies can afford to pay for the privilege of allowing the water to How out threngh thetunel. The Worcester Drill. We give herewith an engraving of the Worcester upright self-feediug drill, of which several styles are kept in stock hy Dunham, Carrigan & Co., of this city. The No. 3 upright drill shown is arranged with slip gear, by whieh a quick or slow motion may he given the drill, for light or heavy work, In the late patterns of this size on the same shaft as the crank are light and loose pulleys, so that the drill is availahle for either steam or hand power. The handle may be removed hy releasing a setscrew. The drill is arranged so that Morse’s twist drills may be used without having to huy a chuck for them, as ail sizes of these drills are made to fit. A drill of this size, in this city, has been made to drill even as large as inch and a half holes, hut they are intended for smaller work.

October 20, 1877.] MINING AND SCIENTIFIC PRESS 249 HYDRAULIC MINING IN CALIFORNIA.* No. [By Avo. J. Bowie, Jr, A. B., Mining Engineer. ] Investigation of the Comparative Values of the Ditferent Gravel Strata at North Bloomfield. With their experience of the past and considering the contingencies of proposed explora. tions, and the attcndaut costs of au enterprise which had for its ultimate aim the workiug of the entire auriferons deposit, after mature deliheratien it was (a3 a preliminary step) deemed of paramount necessity to ascertain, as far as practicable, the relative values of the ditlerent strata of the gold-bearing alluvia, so that they might judge to what extent tho prospects would justify their expenditures. <A serics of explorations were subscquently carried out under the immediate supervision of their able cnginccr, Mr. Hamilton Smith, Jr., and the result of his investigation is best given in his own words: “To test the comparativo valucs of ground . developed hy the shaft workings and top gravel, 240 samples, weighing in all two and one-half tons, were taken at even distances from the sides of the drifts, and the same quantity sampled from different layers of the upper hank. These samples were carcfully panned ont, and yielded, the blue $1.10 per ton, the white a largo number of colors, but an inconsiderable weight of gold. Tho gold from the blue dirt was from 50 to 100 times heavier than that from the white gravel.”"+ Although the gross yield from this sampling of the npper gravel was slight, it is anoteworthy fact thatin each of the 240 pans one or more colors of gold were found. Comparative Value of Gravel Strata In Stanislane County. At the Light elaim, Patricksville, a comparative test of top and bottom gravel was made. 58,340 cubic yards top gravely yielded two cents per cuhic yard. The hottom gravel§ (four feet deep) was then washed up, when it was discovered that this ground had been extensively drifted; but notwithstanding this fact, 4,966 euhie yards yielded 55 eents per cubic yard. A trial of top dirt was also made at the Light elaim, La Grange; 41,038 cubic yards top dirti yielded three cents per cubic yard, aud 7,242 eubic yards of bottom dirt** yielded 94 ceuts per eubie yard. Sand Strata. In the gold-bearing drift of the Sicrra Nevada, layers consisting exclusively of wash sand are generally found to contain very little if any of the precious metal{t. In guich miuing it sometimes happens that from the positiou of the bedrock the detrital accunmlations assume the form of reclining cones, the apex repesing pon the top of tho hill, Where such is the ease, the bulk of the gold is concentrated in the lower end of the deposit. These gulches are frequently found to be exceedingly rich. : It is not within the scope of this paper to discuss the origin of auriferous detritus, or in any way to account for the mode of occurrence of gold, but these general facts are merely cited as an explanatory outline of the subject, and to show the reason why a system of sluicing is adopted which bottoms the entire deposit. The Records of Gold Washing. The early record of gold washing extends to the days of the Greeks and Romans. History has famiharized ns with the wonders of the Pactolus and Tagus, and it is a fact§§ that the diggings north of Aquitania produced in two months such a large amount of gold that its price fell 33% throughout the whole of Italy. Gradually, one after the other, the well-known deposits of the Old World have heen exhausted. The alluvia in Siheria, however, kept alive the interest in gold washing, and the subsequent discoveries in California and Australia infused a new life into this kind of mining. Since that time gold washing has been carried ou in different parts of the world on a most extensive scale, hut the application of water under great pressure to ‘‘gold placer mining” is au outgrowth of the present century. lis use is chiefly confiued to the Pacific coast, and consequontly the contributions to miuing literature relative to its application have not been numerous, Hydraulic Mining. It was left to the untiring iugeunity of the Califoruia miner in his battles for fortnne to devise the economical methods of hydraulic Mining, by which mountains of auriferous gravel are removed through the agency of a continuous stream of water, extracting the recious metals stored away by nature, and adfine millions of hidden wealth to the treasures of the world. Independeut of the financial importance of this most modern method of mining, its effects, from the gigantie scale with which itis now carried on, upon the system of drainage of the *A paper read before the American Institute of Mining Engineers of the Wilkes-Barre meeting, May, 1877. tfhe North Bloomsield Gravel Mining Co. Report by H. Smith, Jr., pp. 17-18. $$1,200. 482,775.07, ground two-thirds drifted out. $1,500. 984,709.72. _—" }tFrom Whisky Run te Coquille river, Oregon, the beach sands, formerly very rich, have becn extensively worked for tbree or four miles along the sea-coast. The produetive stratum wasa layer of black sand, onc to twe feet thick, buried from two to five feet below lighter sands. The gold eecurs in minute particles, This sand likewise contained tome platinum and iridosmine.—Zzt. Trans. Cal. Acad. Sciences, W. A. Goodyear, of the State Geo. Survey. §§Strabo, book iv., chap. vi., sec. 12. Foot-note Siuria, p. 4d, couutry as wellas the navigation of rivers, will, sooner or later, bring it iu direct conflict with agricultural and vomniercial iuterests. Apart from the constructiou of ditches and tunnels necessary for the hydraulie washing of the gold-bearing drift, cugmeers, as a rule, have had but little to do with tho suhscquent working of this class of mines. The primitive placer mining of 1853 to 1865 has passed into history. Forty-inch wrought-iron pipes have heen substituted for canvas hose aud stoye-pipes, and with the replacing of ene-inch streams by uineinch diameter nozzles, discharging under 400 feet pressure, the last remuant of the Argonauts * method disappeare 1, and hydraulic mining, With ono gigantic stride, has become an op. eration of sueh inagnitude as to require the aid of science, The Definition of Hydraulic Mining. Hydraulic mining may he detined as the art of extracting gold fromm gold-hearing detritus, i. ¢., surface deposits, placers or washings, by means of water under great pressure discharged through pipes against the aurifcrous imaterial. In working these golt deposits by this method, it is essential to success that there shonld be: first, economical msnagemeut; secoud, ample facilities for grade and dump; third, asuflicient head and an abundant supply of cheap water, As regards the ‘‘economical mnanagement,” the same can be considered a sine qua non for suecess in all enterprises, but it is especially requisite here. as the value of this kiud of miniug is based on the great facility with The Worcester Self-Feeding Drill. which profitahle results can be readily obtained, at trifling cost from washiug vast areas of ground which contain relatively, per cubic yard, insignificant amounts of precious metal, but in the aggregate, when expeditionsly and skillfully worked, give large remunerative returns, The Dump. Without the dump, hydraulic mining is an impossibility. Ou this point too much stress cannot be placed. Where thousands of cubic yards of alluvious are being daily washed from their original positions into cauyons, valleys, streams, or rivers, it is not the accumulations of a few mouths which must be considered, but places must he provided at lower elevations, where the immense hills of gravel, when “‘hydraulicked, + can be re-deposited; aud in general a very much larger superficial area for this is requisite than was originally occupied by the matorial removed, It sometimes happens in claims uear or adjoining one another, working with the sane dump and on a light grade, that tho bedrock in one is lower than that of the other. Where this occurs the claim with the highest bedrock should be the last run off, so as not to interfere with the dump of the lower claim. An illustration of this condition of affairs is afforded by the Patricksville hydrauliclelaims, in Stanislaus eounty, where three claims, one tailing over the other, are annually worked. During the last two years the lowest claim, called the Chesnau, has heen closed in the fall, its dump giviug out, whilst the upper ones continued work. With the return of spriug freshets, the canyon has been cleared of the debris, and washing has been regularly resumed in the Chesuau, continuing as loug as the dump lasted. The upper claim is closed whilst the Chesnau ‘a working, tcf:void the too rapid filling up of the creek. If the two higher claims were worked at the same time, the Chesnau would soon be closed for an indefinite period. *The name is generally applied te those pioneers whe arrived here in 1949-50. -—_ + Tho words “hydraulicked” and ‘‘hydraulicking" are the colnage of the California placer miner, and custom has here sanctioned their use, Tailing into Streams. _ It is supposed hy many that the want of dump is remedied hy discharging into a current or motutaiu rapid. This eudeubtedly would be so, were the gold placers to border on large, rapid, aud well confined streams; hutin the mountains

where tho gold-bearing deposits are found, the rivers are narrow and shallow, only running water in quantity during the winter and carly spring. Seie of the annoyances and difficulties arising froin tailing into a stream can he seen on the Tuolumne river below La Grange, Tho river for 17 miles above the town has a fall approximating 1S fect to the mile. It is a large mountain stream (fed hy the snows and rains of the Sierra Nevada), well confined by ahrupt hanks. * At La Granget its width is 525 fect. Three hundred yards helow the town, opposite the Light claim, it widens te 750 feet. Bown the stream from this point the hills for the succecding three or four iniles recede, but suhsequently form prominent banks of the river. her! high water in the winter, opposite the Light claim at its greatest width, its average depth was ten fect,§ the center of the channel being 14 feet deep. When the La Grange hydraulic mining company commonced work, in 1872, the bottom of the channel was a few feet deeper. The Light claim was worked iu 1873, and hy June 23d, 1874, 720,086 cubie yards of gravel had been discharged into the stream near the claiin, and during the same period 975,064 cubic yards were dumped into the river from the Kelly and Vrench hill properties. ‘The results at the expiration of 21_ months were that the channel opposite the Light claim was filled up, the sluices were run out of grade, the river bed was shoaled on all sides, the water of a former rapid stream straggled over the accumulated debris with a hardly perceptible motion, and it is hardly necessary to add that the claim was closed. The spring freshets of 1875-76 were unusually severe, elearing the river at the claim for its entire width, and leaving a dump of over 1] feet along its west bank. ‘This spriugll (1876) work was resumed, and since then 48,280 cubic yards have been moved in the Light, aud Green’s Improved Harrow. 212,346 enbie yards from French hill, which is a quarter of a mile up stream. At present** the river is filled up nearly its eutire width to the hight of the sluices, aud the water is confined toastrip 30 feet wide discharging one foot deep over a bar. Where a small amount of tailiugs is discharged into narrow and steep canyons, winter rains and spring freshets suffice to clean them out, but where the quantity is large, in spite of the water the ravines gradually fill up, and hydraulie mining in those localities ultimately ceases. It occasionally happens that the want of dump room is obyiated hy a tunnel, and by means of it the tailings are eonveyed into large and precipitous ravines, eonsigning them to the aetion of time and water for their further remoyal, — “3 Errata.—Last issue, page 233, first column, second paragraph, fourth line, for ‘‘ western houndary” read eastern boundary, also same page, fourth column, fourth paragraph, secoud live for ‘‘ Mandango,” read Mandanga. * The river opposite the old French Hill dump is 500 feet wide. + At the ferry. The grade of the river from hore to its mouth is only a few feet to the mile. {Extreme width during high water. Width at lower sluice 700 fect. § Deeper in narrow places. . April 10th work was resumed on top dirt, ** Dry season--nionths uf August, September'and October. Evoaryptus Firz-Proor,—At the last mecting of the Academy of Scieuces Dr. Baer invited the attentiou of the Academy to a eucalyptus tree stauding in the grounds of the old German hospital, on Brannan street. The tree had passed through the fire of Augnst, 1876, and exhibited the peculiarity of resisting the action of fire—a property well nnderstood in Australia. Dr. Kellogg stated that eucalyptus shingles were in common nse in Australia, on account of their heing fire-proof. It was impossible to fire a roof made of this material. ‘There were some 132 species of eucalypti, hut all seemed te possess this nou-combustible property to some extent. Dr. Gibhon said that the planting of trees in the public strcets would he an important means of checkiug a conflagration, and as the eucalyptus seemed to be peculiarly valuahle for that purpose, and for building, the attention of the public should be called to it. Tue Continental Ore and Transportation Company have established depots at Ogden and other points of the Union Pacific and Central Pacifie railroads, and they have selected Reno as the point of supply of Nevada with coal and turpentine. An Improved Harrow. James B. Greene, of Elliott, San Joaquin county, has patented, through the Mixrxe anp Scientiric Press Patent Agency, an improved harrow, au engraving of which is shewn on thia page. The improvement consists in so eonstructing an A-shaped harrow that the bars or timhers to which the teeth are secured are hinged to a supplemental frame, and by means of connecting reds and levers, any one or more of these sets of teeth may he turncd alternately so as to relievo themselves of the rubhish which may accumulate before them aud thoreughly clean themselves. ‘The uuinber of sets of teeth may be multiplied or iucreased at will, and two er moro sets inay be united and operated by the same lever. When working ordinarily the levers will be retained by a central uctch in a curved rack, hnt wheu the harrow becomes clogged the lever controlling the frout pair of harrows is released aud turned to one side. The movemeut causes the hinged timber upon tho side to turn, so that tho teeth point hack. ward and this allows them to be wiped clean of the rubbish. Meantime, the movement of the lever around its fuleram will point the opposite set of teeth a little forward, aud they will coutiune to work until the lever is turned to the opposite side, when the relative positions of these two scts of teeth will be reversed and the opposite set will be cleaued. While this is being done the rear pair of harrows are still at work, so that there will be no portion of the ground not harrowed, and they will also serve to keep the harrow level and prevent it from pitching forward with the timbers upou the ground. After the front sect are eleaued, the lever is sct straight and the rear lever is operated so that the rear pair of harrows will undergo the same operation and become cleaned. A pair of wheels may be attached to the rear of the harrow and support a seat. The Mines and the Sutro Tunnel. A meeting of the superintendents of the Comstock miues was held in Virginia City on Tuesday. There were present: E, A. Schultz of the Bullion, Excheqner aud Justice; Judge Strother, of the Baltimore and American Flat; Chas. Foreman, of the Overman and Caledonia; N. C, Hall, of the Silver Hill; Mr. Perkins, of the Dayton; Hank Smith of the Belcher; Capt. Taylor, of the Yellow Jacket; Lon. Hamilton, of the Imperial and Alpha; Cal. Derby, of the Alta; J. L. Reqna, of the Chollar; P. Deidesheimer, of the Hale & Norcross; Cal. Gillette, of the Savage; Col. Osbiston, of the Gould & Curry aud Best & Belcher; W. H. Patten, of the Con. Virginia and California; Capt. Hardy, of the Ophir, Mexican and Union Consolidated; Chas. Bonnemont, of the Sierra Nevada; Jno. W. Mackay and Frank Thayer, of the Julia. The meeting was called to order by Mr. Requa, at half-past two. The necessity of action of some sort, with regard to the Sutro tunnel, was admitted by all, and a committee was appointed to examine iuto the question in its various bearings, inclnding the cost of the tunnel, the benefit it is likely to be to the mines, the cost of pumping water to the surface from the tunnel level, etc. The Committee is to report as soon as possible. The Committee is composed of Messrs. Schultz, Requa, Foreman, Patten and Taylor. John Mackay was called upon by the Associated Press reporter after the meeting. He said the Committee would lahor both in Virginia and iu San Francisco, and thought they would make their report in two or threo weeks. Mr. Sutro says his tunnel will havo cost $5,000,000 hy the time it shall have reached the Comstock, and he wants the mining companies to pay him interest npon that amount. The opposite party, however, claim that the eost was not over $2,000,000, aud do not favor Sutro’s proposition. This Committee is to ascertain the exact cost of pumping or draiuiug the water from the various mines of the Comstock from the level of the Sutro tunnel to the surlace, a distance of 1,650 feet, or thereabouts, also the cost of pumping up the level of the tuunel, and, in short, ascertain just what the companies can afford to pay for the privilege of allowing the water to How out threngh thetunel. The Worcester Drill. We give herewith an engraving of the Worcester upright self-feediug drill, of which several styles are kept in stock hy Dunham, Carrigan & Co., of this city. The No. 3 upright drill shown is arranged with slip gear, by whieh a quick or slow motion may he given the drill, for light or heavy work, In the late patterns of this size on the same shaft as the crank are light and loose pulleys, so that the drill is availahle for either steam or hand power. The handle may be removed hy releasing a setscrew. The drill is arranged so that Morse’s twist drills may be used without having to huy a chuck for them, as ail sizes of these drills are made to fit. A drill of this size, in this city, has been made to drill even as large as inch and a half holes, hut they are intended for smaller work.