Volume 39 (1879) (446 pages)

i: 5, eacnted hy the double lines, i, i, (Fig. 1), aad th: INY, 1898. An Illustrated Journal of Mining, Popular Science and Gen eral News. BY DEWEY & OCO., PubuUshera, VOLUME AXXIX Wumber 1, Earthquakes.—No. 2. Ths most conspicuous oxample of a vorticose earthquake, in which the ground is twisted and whirled around and back, occurred in the great Calabrian earthquake of 1783. Blocks of stons forming obelisks wers twistcd ons on another ; ths earth was broken and twisted, so that straight rows of tress wers left in intsrruptsd zigzags. Similar phenomena were observed in the Cslifornia earthquake of 1868. Chimneytops were separated at their junction with the roof, and tivisted around without overthrow ; wardrobes and burcaus wsre turned about at right angles to the wall,or even with thsir faces to tho wall. Thess phenomena may hs explained by the backward and forward motion common to all earthquakes—ths sudden liftiug np of ons end by a forward motion, would swing around by the sudden backward motion. Ths concurrence and interforencs of earth-waves would produce the rsal vorticose motion. [If two systems of waves of any kind meet each vther, thers will hs points of concurrence whsrs t»ey re-enfores each othsr, and points of intsrf enco whers they destroy cach other. Sup1 3, for example, a system of water waves, sauniagin the direction A, }, strike against a wai, w, w; ths waves would be reflected in ths direeton c, c, and are rspresented by the single Ines ,7. Then, if the lines represent crests, *“ ervening spacs the troughs, at the slsce, ‘ced with crosses and dots there would «con urcence, and, thsrefore, highsr crests and seper sroughs, while at ths points indicated by «43h tuere would be interference and mutual inn, and, therefors, smooth water. wo systems of earth-waves meet and other, we must havs points of con. nd interference in close proximity. ecuud, thersfore, will be thrown into vioigus ,.tation—points in close proximity moving in o* osite directions (twisting). If the motic: o sufficient to rupturs the carth, restoranot mads hy counter-twisting, and ths” b. is Isft in a displaced condita i. The cause of this interferencs lies in the different velocity of wavee—as has been explained, an inequality in the medium. It is a noticeahle fact that the most violent earthquakes, especially twisting of . decreasing heyond SAN FRANCISCO, SATURDAY, JULY 5, 1879. It has been observed that in a csrtain zons, a considcrable distancs from the epicsntrum, the destruction by ovarthrow is very great, and bsyond it the effects specdily diminish. This zons has been called the circls of principal destructiou or overflow. This depsnds not so much on the amount of oscillation as upon ths horizontal nature of ths oscillation. The oscillation or vibration is of course greatest at ths point of first emergencs, ths pricen aD, and decreases outward, The oscillation increasing at the epicentrum and that. Under the influence of these two contrary elements, there must exist a point‘or circle on every side of the cpicentrum when the horizontal element will bs amaximum. This is shown in Fig. 3, iu which a a, 6b, ce ¢, stc., are the decreasing oscillation, and 4 6”, cc”, are ths horizontal elemsnt. This reaches a maximum ate It has been found by mathematical calculation, based upon the supposition that ths whole oscillation varies inversely as ths. squars of ths distance from X, that ths horizontal elemsnt will be a maximum when the angls of emergence is 54°, 44. By determining hy ohservation the circle of principal disturbances, it is easy to calculate the depth, a, X, of ths forces, for it will be the apex of a. cone whose base is that circle and whose apical angle is 70° 32’. It has been uoticed that shocks are sometimes FIG. 2. the ground, occur near the junction of the softer strata of the plains with the harder and more elastic strata of the monntains, as will appear from Fig. 2. From the point of the shock, X, suppose earth-waves to emerge at a, and run as a surfacewave toward the mountain, m. The waves, striking the bard, elastic mi ierial, m, would be partly transmitted and partly reflected. The reflected waves, running in the direction of the arrow, 7, would meet the advancing incident waves moving in the direction of the arrow, i, and concurrence and interference would be inevitable. The hollow mumbling, rolling or grinding preceding and accompanying an earthquake are produced by the rupture ofthe earth at the origin, and by the passage of the wave through the variahle elastic medium, being the eound produced by the breaking of the medium and the grinding of the broken parts together. Waves of every variety of size are transmitted, the preat waves being sensible as shocks, jars or tremors, while the small waves which do not produce tremore are heard as sounds, The smaller waves running faster than the large ones, are heard first, and thus precede the shock. Whether the direction of the earthquake be up and down, back and forth, or oblique, the observed motion is due to the position of the observer, At the outcrop the motion would be np and down, becoming ohlique the further the observer recedes from the epicentrum, until ata hreat distance the motion is usually horizontal. The rocking motion is due to 2 series of waves which pass beneath the observer, waves similar in form to water waves, FIG. 1. CONCURRENCE AND INTERFERENCE. waves, and producing graat commotion in these strata. Now, if the inelastic strata §, S, be located at ths bottom of a mine, the sams effect would be apparent, viz., ths undulations would be retlected at the bottom of the strata, to reappear at the surface of the ground abovs the strata, In the earthquake regions of South America there are csrtain favored spots, often of small extent, which are partially exempt from ths shocks which in-. fest the surrounding country. The wave seems to pass under them as under a bridgs to reappear again on ths other side, An inspection of Fig. 5 will explain the cause to bs reflection from an under surface of inelastic strata, According to Mallet, the geological structure of the earth, the formations at ths surface and below the surface, have nearly everything to do with the violence of the earthquake, Two cities may be near together, yet one would be totally destroyed by the shock, and the other entirely escape, or different houscs may sscaps or suffer according to the strata upon which they rest. Immunity from earthquakes may be had, few, if any, human lives need ever be lost. by earthquakes even in volcanic countries. There, earthquakes recur in thsir ‘‘times and seasons,” and to be dealt with, like all human difficulties, they must be understood. The informed faculties and energies of FIG, 3. ‘Mechanical Interests_of the Coast. There is no industry so intimately connscted with mines and mining than the mechanical necessities of this coast. Ths immense deposits of precious metals continually being dsveloped and discoversd require the aid of perfectly working mschinery such as can be properly furnished by our own manufactories. Recent statistics declars that ths annual demand of the world for ths precious metals now falls short by $160,000,000, Ths decrease of 20% in our own productions is felt not only here but in the East, and in seeking for ths cause a cure has been proposed by Eastern machinery huilders. It is a truth which evsry business man now knows, that Chicago and St. Louis are not only making strenuous efforts to compets with San Francisco, but notably in Arizona and Colorado have actually forestalled our markets, The facilities for manufacturing ought not to be greaterin the East than here, besides our mining characteristics have developed a scientific knowledge of the needs of mincral regions, such as the Eastsrn maunfacturer cannot possibly have except in theory. It certainly cannot bs said that the intelligence or business policy of onr coast is less than that of the East, yet with the enormous quantity of rich mineral within our reach and waiting for us to work it into bullion, the East steps in and proposes to monopolize a business which should hs kept hers at home. If the movement should be successful and trade in machinery bs diverted from San Francisco, that interest hero will languish and become subsidiary to the monopolizing tendsncy of Eastern manufacturers. Already Philadelphia sends her machinery to all quartsrs of ths globe, taking advantage of our weakness for big trees and monstrosities in fruits and vegetables to undermine an industry which if not the only element of what is to glorify our future, is at 1east the main element. Floundering in the mud of stock gambling, ths very foundation of our future prosperity is quietly slipping from under us, not without our knowledgs, but without our interference. It is perfently legitimate for us to fear whatever will tend to injurs our present and future, andfwhen we say FIG. 5. that Eastern efforts are succeeding, we would inculcate the idea that unless we awake from our sloth and put forth such efforts as San Francisco alone knows how to pnt forth when aroused to the necessity of action, our slumher will be eternal in the direction of our mechanioal interests, The old pan and rocker idea of gathering the precioue metals has passed into oblivion, yet it would seem as if the bullion product of our mines was believed to originate in the old-fashioned easy way. Expensive and perfect machinery is now required, and the whole world sees it, and seizes the advantage offered by a non-competing locality to our detriment. It may DIAGRAM ILLUSTRATING REFLECTION OF EARTHQUAEE WAVES. distinctly felt in mines which are insensihle at the surface, and again are felt at the surface and not felt inthe mine. This latter has lately happened in our own mines, and may he explained in both casee by the elasticity of the strata, the depth of the impulses or ohstacles that may have changed the course of the terrestrial undulatione. In Fig. 4, S, §, represents the surface of the ground; a, 0, hard, elastic strata, covered with Joose, inelasticmatertals; c, c, earth, gravel, etc, Now, if a seriee of waves come in the direction of the arrowe, d, d, and, passing through a, 6, on their way to the surface, etrike upon the lower surface of ¢, ¢, a portion would reach the eurface hy refraction, but a greater portion would be reflected and retur#into a, 2, concurring and interfering with the advancing a man may avert the evils of the earthquake, in like manner as all others incident to his estate, hy his application of forethought, and knowledge to subjugate by skill, labor aud ohservation. PrerroLEuM,—Crude petroleum went down to 63} cents a barrel, Saturday last, the lowest point ever reached at New York, and refined oil is worth only 7} cents a gallon. The average price of the crude product last year was $1.37 a barrel; the highest price ever paid was $20 a harrel, in 1860. The cause of the present depression is the enormous average yield of 54,000 barrels a day, against 50,000 in April, 48,000 in March, and 40,000 a year ago. . be useless to talk ahout this matter, for “no man is a prophet in his own country.” The facts remain nevertheless that other manufacturers are gradually establishing a market which will draw to the Hast other industries, and deprive us of opportunities that are now within our reach and retention. It is not jealousy that induces us to point to the facts, but a laudable desire for local interests, which all men feel. It is well to he cosmopolitan in talk, hut then ideas do not build up trade and commerce. Sun-Treasurer SHERMAN has shipped $17,000,000 in gold coin to the East as third-class mail matter during the past eight months. Lately the shipments have heen made under a government frank, and without cost. Apvrces from Guaymas indicate that the early building of a railroad from that point to El Paso or elsewhere is unlikely, the Mexican government preferring fighting to improving.

i: 5, eacnted hy the double lines, i, i, (Fig. 1), aad th: INY, 1898. An Illustrated Journal of Mining, Popular Science and Gen eral News. BY DEWEY & OCO., PubuUshera, VOLUME AXXIX Wumber 1, Earthquakes.—No. 2. Ths most conspicuous oxample of a vorticose earthquake, in which the ground is twisted and whirled around and back, occurred in the great Calabrian earthquake of 1783. Blocks of stons forming obelisks wers twistcd ons on another ; ths earth was broken and twisted, so that straight rows of tress wers left in intsrruptsd zigzags. Similar phenomena were observed in the Cslifornia earthquake of 1868. Chimneytops were separated at their junction with the roof, and tivisted around without overthrow ; wardrobes and burcaus wsre turned about at right angles to the wall,or even with thsir faces to tho wall. Thess phenomena may hs explained by the backward and forward motion common to all earthquakes—ths sudden liftiug np of ons end by a forward motion, would swing around by the sudden backward motion. Ths concurrence and interforencs of earth-waves would produce the rsal vorticose motion. [If two systems of waves of any kind meet each vther, thers will hs points of concurrence whsrs t»ey re-enfores each othsr, and points of intsrf enco whers they destroy cach other. Sup1 3, for example, a system of water waves, sauniagin the direction A, }, strike against a wai, w, w; ths waves would be reflected in ths direeton c, c, and are rspresented by the single Ines ,7. Then, if the lines represent crests, *“ ervening spacs the troughs, at the slsce, ‘ced with crosses and dots there would «con urcence, and, thsrefore, highsr crests and seper sroughs, while at ths points indicated by «43h tuere would be interference and mutual inn, and, therefors, smooth water. wo systems of earth-waves meet and other, we must havs points of con. nd interference in close proximity. ecuud, thersfore, will be thrown into vioigus ,.tation—points in close proximity moving in o* osite directions (twisting). If the motic: o sufficient to rupturs the carth, restoranot mads hy counter-twisting, and ths” b. is Isft in a displaced condita i. The cause of this interferencs lies in the different velocity of wavee—as has been explained, an inequality in the medium. It is a noticeahle fact that the most violent earthquakes, especially twisting of . decreasing heyond SAN FRANCISCO, SATURDAY, JULY 5, 1879. It has been observed that in a csrtain zons, a considcrable distancs from the epicsntrum, the destruction by ovarthrow is very great, and bsyond it the effects specdily diminish. This zons has been called the circls of principal destructiou or overflow. This depsnds not so much on the amount of oscillation as upon ths horizontal nature of ths oscillation. The oscillation or vibration is of course greatest at ths point of first emergencs, ths pricen aD, and decreases outward, The oscillation increasing at the epicentrum and that. Under the influence of these two contrary elements, there must exist a point‘or circle on every side of the cpicentrum when the horizontal element will bs amaximum. This is shown in Fig. 3, iu which a a, 6b, ce ¢, stc., are the decreasing oscillation, and 4 6”, cc”, are ths horizontal elemsnt. This reaches a maximum ate It has been found by mathematical calculation, based upon the supposition that ths whole oscillation varies inversely as ths. squars of ths distance from X, that ths horizontal elemsnt will be a maximum when the angls of emergence is 54°, 44. By determining hy ohservation the circle of principal disturbances, it is easy to calculate the depth, a, X, of ths forces, for it will be the apex of a. cone whose base is that circle and whose apical angle is 70° 32’. It has been uoticed that shocks are sometimes FIG. 2. the ground, occur near the junction of the softer strata of the plains with the harder and more elastic strata of the monntains, as will appear from Fig. 2. From the point of the shock, X, suppose earth-waves to emerge at a, and run as a surfacewave toward the mountain, m. The waves, striking the bard, elastic mi ierial, m, would be partly transmitted and partly reflected. The reflected waves, running in the direction of the arrow, 7, would meet the advancing incident waves moving in the direction of the arrow, i, and concurrence and interference would be inevitable. The hollow mumbling, rolling or grinding preceding and accompanying an earthquake are produced by the rupture ofthe earth at the origin, and by the passage of the wave through the variahle elastic medium, being the eound produced by the breaking of the medium and the grinding of the broken parts together. Waves of every variety of size are transmitted, the preat waves being sensible as shocks, jars or tremors, while the small waves which do not produce tremore are heard as sounds, The smaller waves running faster than the large ones, are heard first, and thus precede the shock. Whether the direction of the earthquake be up and down, back and forth, or oblique, the observed motion is due to the position of the observer, At the outcrop the motion would be np and down, becoming ohlique the further the observer recedes from the epicentrum, until ata hreat distance the motion is usually horizontal. The rocking motion is due to 2 series of waves which pass beneath the observer, waves similar in form to water waves, FIG. 1. CONCURRENCE AND INTERFERENCE. waves, and producing graat commotion in these strata. Now, if the inelastic strata §, S, be located at ths bottom of a mine, the sams effect would be apparent, viz., ths undulations would be retlected at the bottom of the strata, to reappear at the surface of the ground abovs the strata, In the earthquake regions of South America there are csrtain favored spots, often of small

extent, which are partially exempt from ths shocks which in-. fest the surrounding country. The wave seems to pass under them as under a bridgs to reappear again on ths other side, An inspection of Fig. 5 will explain the cause to bs reflection from an under surface of inelastic strata, According to Mallet, the geological structure of the earth, the formations at ths surface and below the surface, have nearly everything to do with the violence of the earthquake, Two cities may be near together, yet one would be totally destroyed by the shock, and the other entirely escape, or different houscs may sscaps or suffer according to the strata upon which they rest. Immunity from earthquakes may be had, few, if any, human lives need ever be lost. by earthquakes even in volcanic countries. There, earthquakes recur in thsir ‘‘times and seasons,” and to be dealt with, like all human difficulties, they must be understood. The informed faculties and energies of FIG, 3. ‘Mechanical Interests_of the Coast. There is no industry so intimately connscted with mines and mining than the mechanical necessities of this coast. Ths immense deposits of precious metals continually being dsveloped and discoversd require the aid of perfectly working mschinery such as can be properly furnished by our own manufactories. Recent statistics declars that ths annual demand of the world for ths precious metals now falls short by $160,000,000, Ths decrease of 20% in our own productions is felt not only here but in the East, and in seeking for ths cause a cure has been proposed by Eastern machinery huilders. It is a truth which evsry business man now knows, that Chicago and St. Louis are not only making strenuous efforts to compets with San Francisco, but notably in Arizona and Colorado have actually forestalled our markets, The facilities for manufacturing ought not to be greaterin the East than here, besides our mining characteristics have developed a scientific knowledge of the needs of mincral regions, such as the Eastsrn maunfacturer cannot possibly have except in theory. It certainly cannot bs said that the intelligence or business policy of onr coast is less than that of the East, yet with the enormous quantity of rich mineral within our reach and waiting for us to work it into bullion, the East steps in and proposes to monopolize a business which should hs kept hers at home. If the movement should be successful and trade in machinery bs diverted from San Francisco, that interest hero will languish and become subsidiary to the monopolizing tendsncy of Eastern manufacturers. Already Philadelphia sends her machinery to all quartsrs of ths globe, taking advantage of our weakness for big trees and monstrosities in fruits and vegetables to undermine an industry which if not the only element of what is to glorify our future, is at 1east the main element. Floundering in the mud of stock gambling, ths very foundation of our future prosperity is quietly slipping from under us, not without our knowledgs, but without our interference. It is perfently legitimate for us to fear whatever will tend to injurs our present and future, andfwhen we say FIG. 5. that Eastern efforts are succeeding, we would inculcate the idea that unless we awake from our sloth and put forth such efforts as San Francisco alone knows how to pnt forth when aroused to the necessity of action, our slumher will be eternal in the direction of our mechanioal interests, The old pan and rocker idea of gathering the precioue metals has passed into oblivion, yet it would seem as if the bullion product of our mines was believed to originate in the old-fashioned easy way. Expensive and perfect machinery is now required, and the whole world sees it, and seizes the advantage offered by a non-competing locality to our detriment. It may DIAGRAM ILLUSTRATING REFLECTION OF EARTHQUAEE WAVES. distinctly felt in mines which are insensihle at the surface, and again are felt at the surface and not felt inthe mine. This latter has lately happened in our own mines, and may he explained in both casee by the elasticity of the strata, the depth of the impulses or ohstacles that may have changed the course of the terrestrial undulatione. In Fig. 4, S, §, represents the surface of the ground; a, 0, hard, elastic strata, covered with Joose, inelasticmatertals; c, c, earth, gravel, etc, Now, if a seriee of waves come in the direction of the arrowe, d, d, and, passing through a, 6, on their way to the surface, etrike upon the lower surface of ¢, ¢, a portion would reach the eurface hy refraction, but a greater portion would be reflected and retur#into a, 2, concurring and interfering with the advancing a man may avert the evils of the earthquake, in like manner as all others incident to his estate, hy his application of forethought, and knowledge to subjugate by skill, labor aud ohservation. PrerroLEuM,—Crude petroleum went down to 63} cents a barrel, Saturday last, the lowest point ever reached at New York, and refined oil is worth only 7} cents a gallon. The average price of the crude product last year was $1.37 a barrel; the highest price ever paid was $20 a harrel, in 1860. The cause of the present depression is the enormous average yield of 54,000 barrels a day, against 50,000 in April, 48,000 in March, and 40,000 a year ago. . be useless to talk ahout this matter, for “no man is a prophet in his own country.” The facts remain nevertheless that other manufacturers are gradually establishing a market which will draw to the Hast other industries, and deprive us of opportunities that are now within our reach and retention. It is not jealousy that induces us to point to the facts, but a laudable desire for local interests, which all men feel. It is well to he cosmopolitan in talk, hut then ideas do not build up trade and commerce. Sun-Treasurer SHERMAN has shipped $17,000,000 in gold coin to the East as third-class mail matter during the past eight months. Lately the shipments have heen made under a government frank, and without cost. Apvrces from Guaymas indicate that the early building of a railroad from that point to El Paso or elsewhere is unlikely, the Mexican government preferring fighting to improving.