Volume 39 (1879) (446 pages)

118 MINING AND SCIENTIFIC PRESS. [August 23, 1879, A Problem in Transmission of Power. [Abstract from a thesis by Cuarnes W. SLACK, Collere of Mechanics, University of Catifornia.] Wire rops transmission hecomes a valuahle msans of trausferring powsr to long distances whsn a weaker material will not answer; and ths lightnsss, durahility and cheapness of the rope are important factors for the mechanical engiueer to consider. For a country ike Calirornia, having ahundance of water power, and where it is often impossihle or inconvenient to utilize directly the power near the water, which in manufacturing, such a system of transmission is especially valuahle. The principle-on which it depends is either to use a large rope working at a low speed, or what is hetter, a small rope working at a great velocity. In order to illustrate telodynamic transmission, I will discuss an ideal case: Suppose it is desired to transmit 200-horse power from the vertical shaft of a turhine at A, 250 ft. to a bluff, C, 300 ft., and thence across a valley 1,000 feet, from D to some couvenient point, B, for a mill. Required: (1). The size of the rope necessary to convey the given power. (2), The diameter of the pulleys. (3). The length of rope. (4). The loss of power, (1). The Size of the Rope. Allow a velocity of 5,280 ft. per miu., or 88 ft. persec. The work performed is : Les Py=550x H P; From which the resistance, P=550 x 200+ S8— 1,250 tbs. The ratio of the tensions on the driving and driven portions of the rope due to the resistance to slipping is Po +P) —2; and since the driving force of the rope is the difference of tensions, P=P2 —Pi or Pj =P, and Pg =2P. Arope must he selected which is capable of sustaining the greatest tension, Pe =2P=2,500 Ibs. According to Mr. A, S. Hallidie, an irou wire rope of 24 in. in circumference, or a diameter of .716 in., is required for a working load of 2,500 Ibs, (2). The Diameter of the Pulleys. The ropeis suhjected to two different etraining actions. Besides the longitudinal tension due to the work transmitted and the weight of the rope, there are stresses due to the hending of the rope over the pulleys. Z=diameter of each wire composing the rope. pt = greatest workingstress due to the longitudinal tension of the rope. Re == corresponding strain due to bending.= total longitudinal tension of the rope. m =number of wires in the rope. For tho stretched wiree in passing over a pulloy, P=Pb + pt. The hending moment is given by the well known relation, . EW San: In which E-modulus of elasticity of the material bent, W=moment of inertia, and R=ra. dius of the pulley. The strain on the remotest fiher from the neutral axis of the wire due to bending is . 2W Substituting the abovo value of M, we have ZE poi The total longitudinal tension ie the tension on a unit area multiplied by the sectional area of the rope; or PiZm L=ptx f From which T pb =p> [eam 7 Substituting the values of pp and py just deduced in the equation p x pp +, pt, we have oS i ZE = Pi x TR 2m Hence Pi ZE D5 NO eae. To find a value of Z when T is a maximum, place the first differential coefficient of T with reference to Z equal to zero; or 2 2p a ==0; 4p Z2=Rx 3B or For wrought iron, p=24,000, and E=29, 000,000; hence _Rk 900 For a rope of .716 inches in diameter Z=: -0699 inches, very approximately. ‘Therefore, the radius of the soe is 5.24 feet for the minimum limit, To he on the safe side, in. crease R to 7 feet. (3). The Length of the Rope. The general equation of the catenary curves formed hy the rope ie @,8= 2 Y~zlee ee) in which y and x are the general co-ordinates e, the bass of the Napernian system. Developx x ing eg and e¢ intoa simple form, we have x x . ex 1 x eoTltatya (co +pa3 GP +ete. and x x onl “ee ak I, 2 -jes =)3 +ete. 12.3 () ( i] e x By ths substitution of these valves of ec aud ee . e g in the general equation, and rejecting all the higher powers of = which we may do without seusihle error provided = is a small fraction, x2 y=+9e we have Thus it is seen that the equation of the cate nary is approximately the equation of an in verted parahola referred along its axis to an origin at a distance, c, helow the vertex. Hence, the vertex is determined by the equation c 2 _* ht+e=» (.¢7 , 9 or approximately hy2e in which h is the distance of the vertex below the horizontal line connecting the poinss of suspension. The general equation for the deflection in terms of 1, tho length of the curve from one of the points of suspension to the vertex, and c is h+c=V/i2 +c? from which l=V/b? +2he If K =tension in a tangent at auy point of the curve, the equivalent tensione are a vertical tension, VY =q 1, and a horizontal tension, H= q ¢; q heing the weight per lineal foot of the rope. From the preceding, K=\/H?2 + V2 = a, at qve +1 =alh+e)=a(b +5 It is evident that the tension at D is greater) than the tension at A; and if the power was transmitted from A to D direct, the tension at D would he greater than the selected rope could stand with safety. In order to reduce the tension at D as much as possible under the circumstauces, place at C, to carry the driving and driven portions of the rope, two parallel guide pulleys, as close together as practicable, in such a manner that their lower rims shall he at the same hight as the horizontal pulley at A. Also place two parallel guide pulleys as near as _possible to A, so that the rope can lead fair on and from tho groove in the rim of the horizontal pulley, and two at D that the rope betwecn C and D may hang perfectly vertical. Since the tension on the driving and driven ropes changes when the system is in motion, it is evident that the catenary curves will change. We will now consider their positions when the ayatem is at rest and when in motion: Po =tension at A and C’ when at rest. Pi =tension on driven side. P2 =tension on driving side. ho hi and he =corresponding position of the vertex below the horizontal, Po = fait ; but Pi= na ; hence Po — #P2. Pe =2500 ibs; and q=.86 Ibs, From Po =q (ho + a) » ho =4,18 ft. The tension be. ho ing the same for the two catenaries between A and C, the vertices will be at the same distance from the horizontal. ‘When in motion the tension, P1, on the driven side, is 1,250 tbs., and hi =5.40 ft, ho = anual ; whence he =2,96 ft., for the vertex of the driving catenary, The length of one of the catenaries, from one of the points of euspension to the vertex, when the system is at rest, is l= \/h? + 2 Te, ¢= Pa 1,869.13 ft., and 1—125.1 ft. Hence the total length of rope required for the two catenaries is 41=500.4 ft. Again let T=tension at D and B when at rest, T=tension on driven side, T =tension on driving side, Mo, Mi and Ma =corresponding positions of the 300 ft. of rope between C and D of points of the curve, c, some constant, and consequently T2 2,758 hs,, DIAGRAM ILLUSTRATING TELODYNAMIC TRANSMISSION. 2,08.5 ths., and c=2,228.51 ft., which gives Mo =141.35 ft. When in motion, the tension on the driven sids is 1,508 Ibs., and M1 =179.6 ft. Me, the deflection due to T2 is 103.1 ft, 11 =812.39 ft., determined as hefore, and ths length for the live catenaries is 411 = 3,249.56 ft. The ropo may he considered, without sensihle error, 28 emhracing one-half ths cireumferencs of the pulley at A, and one-half at B; the remaining pulleys, heing simply guides, do not affect the length sensihly, ‘The total length of rope required ie therefore 3=2Pi R+500.4+ 600 + 3,249.56 —4, 393.94 ft. (4). The Loss of Power. Experience shows that only the friction of the shafts of the pulleys on the hearings diminishes the power in wire-rope transmission. Allowing a pressure of 4P on each shaft, and a coefficient of friction of.1, the loss of power amounts to 9 H. P.; the availahle power is therefore at least 95%. Wonders of Venus. Many who admire the heautiful star which now adorns the western sky until more than three hours after the commencement of twilight, may not he aware that its eplendor is derived from the sun; that in it, like on the earth, night curtains the landscape, morning dawns aud seasons in quick succession come and go. Lofty mozntains show that forces similar to those which upheaved the Alps and lifted the summits of the Andes ahove tbe regions of eternal snow, have ridged its surface and covered it with hills aud vales. Variahle spots prove that clouds float in its atmosphere, and gleams of light, which dart across its sky, afford evidence that in it lightning seams the sky and the thunder’s roll reverherates through the valleys. But 300 miles less iu diameter than the earth, and revolviug on its axis in nearly the same time, Venus makes thirteen revoluticns aronud the sun while the former makes eight, As the inclination of the planet to the plane of its orhit is at least 54°, its torrid zone is douhle that extent, or 108°, and its polar circles 54° from the poles. It therefore has two frigid and a torrid, but no temperate zone, Since the sun must arrive at the equator and depart from it to tho distance of 54° twice in each of its years, there must he two summers and two winters annually in the torrid zones and a winter and a summer in each of tho frigid. Venus becomes the morning star after its superior conjunction, when it appears, through the telescope, cres. cent-shaped lke the new moon. The orhits of this plauet and of Mercury are within the orhit of the earth, and consequently they are never seen in opposition to the sun, that is in the east when the sun is in the west, or in the west and the sun in the east. At its inferior conjunction, Venus is nearer to the earth than auy other planet except the moon, aud sometimes when approaching the greateet distance, when it seeins to recede from the sun, casts a shadow and ie visible in the full light of day. If at the period when it is nearest to the earth, the enlightened part were fully turned toward the latter, this planet would appear twenty times as hrilliant as it now does and almost vie with the moon in dissipating the darkness of night. Being situated at about one-third lese distance from the sun than the earth, Venus receives more light from that luminary than ie received by the former planet, and seems not to require the aid of the moon. Nevertheless, several astronomers have affirmed that they have noticed such a hody, and have even gone so far as to calculate the orbit of the supposed satellite, hut their observations have not heen veriled. The transits of Veuus, or its passage between the earth and the sun, when it appears asa round dark spot moving slowly across the solar diac, have been made to assist in determining the distance of the earth from the central luminary. The last traneit occurred in December, 1874, and the next will take place in December, 1882. As this can be viewed in the United States it will awaken a greater interest than the transit which Rittenhouse and othere observed more than a century apo. But four transits of Venus have been observed, and after . ® 1882, 1214 yeare will elapse hefore the alter. } nately morning and evening star will pnrsue its had not extended upwards and downwards more than two or three inches. room at Glasgow a tuhe about 30 feet long was fusion it has heen calculated that complete interfusion of the two liquids will occupy nearly various sizes, from that of a hickory nut toa peck measure, and, although most of them are emhedded in a tenacious clay or marl, at various distances from the surface, rarely exceeding ten feet, a considerahle quantity lies loosely ahove ground, and until their true nature was discovered, a dozen years ago, were regarded a3 a great disadvantage to the land by the owners. They were detested by the farmers, like our northern drift rocks, which interfere with easy cultivation. mense area—hundreds of thousands of acres— and practically the supply may he said to hs Australian Gold Fields, The last Australian mail brings news of a dis. covery iu one of ths several miues at Ballarat, which hids fair to he of ths greatest importance the most valuable alluvial gold field in the colony. The discovery was the finding of an ex. tensive quartz recf in the claim of the Baud and Alhion Consols Compauy. The mine owned hy that company has in the past yielded grand re. turns of gold from its alluvial washes, and ths new quartz reef was found ata time when it wag worked out, The first returns ohtained from were at the rate of 12 dwt. per ton, hut they speedily improved, until 350 ounces of gold were obtained from 250 tons of quartz. The follow: ing fortnight’s crushing of stone was still hetter, 464 ounces of gold being ohtained from 176 tona of etone, and the yield for the last fortnight was 396 ouncee 12 dwt. The good effect of the discovery on the spirits of miners and those who are interested in mining property has heen mag. ical, and all the unoecupied land under which the new reef is supposed to run has heen eagerly sought after for mining purposcs. It is hoped, indeed, that Ballarat may yet prove to he as rich in auriferous quartz as it has hitherto proved in gold-hearing alluviums. The value of the discovery, so far as the claim itself is con. cerned, may be understood when it is stated that the shares of the company are now sellin at five times the price they were disposed of only ahout six weeksago. The mine is situated in Ballarat West, hut the progress of quartz mining in Ballarat East is also very satisfactory. The Queen Company, a tribute from the Black while the Sulieman Pacha has also come across a promising run of stone at the 300 level, line of reefs, and near where the celehrated Welcome nugget was found, Other claims in ie neighhorhood are also stated to be doing well. of the claims recently etarted there, and itis now prohahle that thie long-neglected field will have a chance of being thoroughly developed hy the influx of outside capital. “An alluvial gold field was found ahout three weoks ago near Dunolly, which promises to he one of the best discoveries of the new ground that has heen an: nounced for a long time past. Nuggets of various sizes, from eleven ounces downwards, have been obtained is some of the élaims at a rush, and a large numher of minere have taken up ground wherever itis thought the gold will be found, At Stawell, one of our principal quartz: miniug districts, miuing is said to he improving from the dullness which has pervaded it for the past few months. Only last week a kiln of 1,111 tons from the Oriental mine there pro: duced the splendid yield of 3,480 ozs. 11 dwts., or an average of ahout 3 ozs. 3 dwts. per tou. The company had then 600 more tons of the same kind of stone ready towards another kiln, The miners of the Pleasant Cieek Cross Reef Company, whose claim has, so far, been one of the richest worked iu the colony, believe that the resf which gave the Oriental crushing just mentioned is close to their houndary, and if that be so, the mine is likely to be very rich indeed, there is nothing of special importance recorded in connection with the other gold fields of the colony, but work, however, is carried on steadily in all of them, and itis helieved the yields are keeping up to the average. Dirrusion or Liquips.—In tho course of a recent lecture at the Royal Institution, Sir W. Thomson made some experimente to show the extreme slowness of the diffusion of liquids, He exhihited tubes filled nine days proviously, which in the upper part contained one fluid, and in the lower another, such asa eolution of sulphate of copper, a solution of common salt, colored alcohol, etc. A mark where the two fluids met was registered at the time the tuhes were filled, and in the nine days the diffusion In a lecture. filled some years ago, and from the rate of dif1,000 years. CuaRLeston PuospHates,—The rocke are of These rocks extend over an imnexhaustihle. Frencu Casie.—The cable steamer Faraday, to the future prespects of the district, hitherto thought the rich alluvial grouud was almost. the reef, which was stated to he 20 feet thick, Hill Company has struck a good hody of stone, on what is known as the Old Prince of Wales _ At Beaufort, work is proceeding on many seeming pathway acroas the surface of the great orh of day.— Albany Journal. ProspHoRESCENCE.—MM. Bancel and Husson have communicated to the Academy of Sciences observations on the phosphorescence of the flesh of the lobster. to a fermentation in which carho and phosphothe vertex helow the horizontal. The weight of . hydrogens are liberated, and which is destroyed ie 258 tbs.;. by putrefaction, just as the hacteria of carbunTo =iT2 = cleare destroyed by the vihriones of putrefaotion, They consider it due having laid the shore-end of the new French Atlantic cahle from the coast of France, has returned to England to take on board the shore: end of the cable to he laid on this side, which she will at once proceed to lay down.: ‘The telegraphic journals express considerable douhta of the financial success of this undertaking, conteuding generally that thero are already more transatlantic cables in operation than are — required for the needs of business, = ae

118 MINING AND SCIENTIFIC PRESS. [August 23, 1879, A Problem in Transmission of Power. [Abstract from a thesis by Cuarnes W. SLACK, Collere of Mechanics, University of Catifornia.] Wire rops transmission hecomes a valuahle msans of trausferring powsr to long distances whsn a weaker material will not answer; and ths lightnsss, durahility and cheapness of the rope are important factors for the mechanical engiueer to consider. For a country ike Calirornia, having ahundance of water power, and where it is often impossihle or inconvenient to utilize directly the power near the water, which in manufacturing, such a system of transmission is especially valuahle. The principle-on which it depends is either to use a large rope working at a low speed, or what is hetter, a small rope working at a great velocity. In order to illustrate telodynamic transmission, I will discuss an ideal case: Suppose it is desired to transmit 200-horse power from the vertical shaft of a turhine at A, 250 ft. to a bluff, C, 300 ft., and thence across a valley 1,000 feet, from D to some couvenient point, B, for a mill. Required: (1). The size of the rope necessary to convey the given power. (2), The diameter of the pulleys. (3). The length of rope. (4). The loss of power, (1). The Size of the Rope. Allow a velocity of 5,280 ft. per miu., or 88 ft. persec. The work performed is : Les Py=550x H P; From which the resistance, P=550 x 200+ S8— 1,250 tbs. The ratio of the tensions on the driving and driven portions of the rope due to the resistance to slipping is Po +P) —2; and since the driving force of the rope is the difference of tensions, P=P2 —Pi or Pj =P, and Pg =2P. Arope must he selected which is capable of sustaining the greatest tension, Pe =2P=2,500 Ibs. According to Mr. A, S. Hallidie, an irou wire rope of 24 in. in circumference, or a diameter of .716 in., is required for a working load of 2,500 Ibs, (2). The Diameter of the Pulleys. The ropeis suhjected to two different etraining actions. Besides the longitudinal tension due to the work transmitted and the weight of the rope, there are stresses due to the hending of the rope over the pulleys. Z=diameter of each wire composing the rope. pt = greatest workingstress due to the longitudinal tension of the rope. Re == corresponding strain due to bending.= total longitudinal tension of the rope. m =number of wires in the rope. For tho stretched wiree in passing over a pulloy, P=Pb + pt. The hending moment is given by the well known relation, . EW San: In which E-modulus of elasticity of the material bent, W=moment of inertia, and R=ra. dius of the pulley. The strain on the remotest fiher from the neutral axis of the wire due to bending is . 2W Substituting the abovo value of M, we have ZE poi The total longitudinal tension ie the tension on a unit area multiplied by the sectional area of the rope; or PiZm L=ptx f From which T pb =p> [eam 7 Substituting the values of pp and py just deduced in the equation p x pp +, pt, we have oS i ZE = Pi x TR 2m Hence Pi ZE D5 NO eae. To find a value of Z when T is a maximum, place the first differential coefficient of T with reference to Z equal to zero; or 2 2p a ==0; 4p Z2=Rx 3B or For wrought iron, p=24,000, and E=29, 000,000; hence _Rk 900 For a rope of .716 inches in diameter Z=: -0699 inches, very approximately. ‘Therefore, the radius of the soe is 5.24 feet for the minimum limit, To he on the safe side, in. crease R to 7 feet. (3). The Length of the Rope. The general equation of the catenary curves formed hy the rope ie @,8= 2 Y~zlee ee) in which y and x are the general co-ordinates e, the bass of the Napernian system. Developx x ing eg and e¢ intoa simple form, we have x x . ex 1 x eoTltatya (co +pa3 GP +ete. and x x onl “ee ak I, 2 -jes =)3 +ete. 12.3 () ( i] e x By ths substitution of these valves of ec aud ee . e g in the general equation, and rejecting all the higher powers of = which we may do without seusihle error provided = is a small fraction, x2 y=+9e we have Thus it is seen that the equation of the cate nary is approximately the equation of an in verted parahola referred along its axis to an origin at a distance, c, helow the vertex. Hence, the vertex is determined by the equation c 2 _* ht+e=» (.¢7 , 9 or approximately hy2e in which h is the distance of the vertex below the horizontal line connecting the poinss of suspension. The general equation for the deflection in terms of 1, tho length of the curve from one of the points of suspension to the vertex, and c is h+c=V/i2 +c? from which l=V/b? +2he If K =tension in a tangent at auy point of the curve, the equivalent tensione are a vertical tension, VY =q 1, and a horizontal tension, H= q ¢; q heing the weight per lineal foot of the rope. From the preceding, K=\/H?2 + V2 = a, at qve +1 =alh+e)=a(b +5 It is evident that the tension at D is greater) than the tension at A; and if the power was transmitted from A to D direct, the tension at D would he greater than the selected rope could stand with safety. In order to reduce the tension at D as much as possible under the circumstauces, place at C, to carry the driving and driven portions of the rope, two parallel guide pulleys, as close together as practicable, in such a manner that their lower rims shall he at the same hight as the horizontal pulley at A. Also place two parallel guide pulleys as near as _possible to A, so that the rope can lead fair on and from tho groove in the rim of the horizontal pulley, and two at D that the rope betwecn C and D may hang perfectly vertical. Since the tension on the driving and driven ropes changes when the system is in motion, it is evident that the catenary curves will change. We will now consider their positions when the ayatem is at rest and when in motion: Po =tension at A and C’ when at rest. Pi =tension on driven side. P2 =tension on driving side. ho hi and he =corresponding position of the vertex below the horizontal, Po = fait ; but Pi= na ; hence Po — #P2. Pe =2500 ibs; and q=.86 Ibs, From Po =q (ho + a) » ho =4,18 ft. The tension be. ho ing the same for the two catenaries between A and C, the vertices will be at the same distance from the horizontal. ‘When in motion the tension, P1, on the driven side, is 1,250 tbs., and hi =5.40 ft, ho = anual ; whence he =2,96 ft., for the vertex of the driving catenary, The length of one of the catenaries, from one of the points of euspension to the vertex, when the system is at rest, is l= \/h? + 2 Te, ¢= Pa 1,869.13 ft., and 1—125.1 ft. Hence the total length of rope required for the two catenaries is 41=500.4 ft. Again let T=tension at D and B when at rest, T=tension on driven side, T =tension on driving side, Mo, Mi and Ma =corresponding positions of the 300 ft. of rope between C and D of points of the curve, c, some constant, and consequently T2 2,758 hs,, DIAGRAM ILLUSTRATING TELODYNAMIC TRANSMISSION. 2,08.5 ths., and c=2,228.51 ft., which gives Mo =141.35 ft. When in motion, the tension on the driven sids is 1,508 Ibs., and M1 =179.6 ft. Me, the deflection due to T2 is 103.1 ft, 11 =812.39 ft., determined as hefore, and ths length for the live catenaries is 411 = 3,249.56 ft. The ropo may he considered, without sensihle error, 28 emhracing one-half ths cireumferencs of the pulley at A, and one-half at B; the remaining pulleys, heing simply guides, do not

affect the length sensihly, ‘The total length of rope required ie therefore 3=2Pi R+500.4+ 600 + 3,249.56 —4, 393.94 ft. (4). The Loss of Power. Experience shows that only the friction of the shafts of the pulleys on the hearings diminishes the power in wire-rope transmission. Allowing a pressure of 4P on each shaft, and a coefficient of friction of.1, the loss of power amounts to 9 H. P.; the availahle power is therefore at least 95%. Wonders of Venus. Many who admire the heautiful star which now adorns the western sky until more than three hours after the commencement of twilight, may not he aware that its eplendor is derived from the sun; that in it, like on the earth, night curtains the landscape, morning dawns aud seasons in quick succession come and go. Lofty mozntains show that forces similar to those which upheaved the Alps and lifted the summits of the Andes ahove tbe regions of eternal snow, have ridged its surface and covered it with hills aud vales. Variahle spots prove that clouds float in its atmosphere, and gleams of light, which dart across its sky, afford evidence that in it lightning seams the sky and the thunder’s roll reverherates through the valleys. But 300 miles less iu diameter than the earth, and revolviug on its axis in nearly the same time, Venus makes thirteen revoluticns aronud the sun while the former makes eight, As the inclination of the planet to the plane of its orhit is at least 54°, its torrid zone is douhle that extent, or 108°, and its polar circles 54° from the poles. It therefore has two frigid and a torrid, but no temperate zone, Since the sun must arrive at the equator and depart from it to tho distance of 54° twice in each of its years, there must he two summers and two winters annually in the torrid zones and a winter and a summer in each of tho frigid. Venus becomes the morning star after its superior conjunction, when it appears, through the telescope, cres. cent-shaped lke the new moon. The orhits of this plauet and of Mercury are within the orhit of the earth, and consequently they are never seen in opposition to the sun, that is in the east when the sun is in the west, or in the west and the sun in the east. At its inferior conjunction, Venus is nearer to the earth than auy other planet except the moon, aud sometimes when approaching the greateet distance, when it seeins to recede from the sun, casts a shadow and ie visible in the full light of day. If at the period when it is nearest to the earth, the enlightened part were fully turned toward the latter, this planet would appear twenty times as hrilliant as it now does and almost vie with the moon in dissipating the darkness of night. Being situated at about one-third lese distance from the sun than the earth, Venus receives more light from that luminary than ie received by the former planet, and seems not to require the aid of the moon. Nevertheless, several astronomers have affirmed that they have noticed such a hody, and have even gone so far as to calculate the orbit of the supposed satellite, hut their observations have not heen veriled. The transits of Veuus, or its passage between the earth and the sun, when it appears asa round dark spot moving slowly across the solar diac, have been made to assist in determining the distance of the earth from the central luminary. The last traneit occurred in December, 1874, and the next will take place in December, 1882. As this can be viewed in the United States it will awaken a greater interest than the transit which Rittenhouse and othere observed more than a century apo. But four transits of Venus have been observed, and after . ® 1882, 1214 yeare will elapse hefore the alter. } nately morning and evening star will pnrsue its had not extended upwards and downwards more than two or three inches. room at Glasgow a tuhe about 30 feet long was fusion it has heen calculated that complete interfusion of the two liquids will occupy nearly various sizes, from that of a hickory nut toa peck measure, and, although most of them are emhedded in a tenacious clay or marl, at various distances from the surface, rarely exceeding ten feet, a considerahle quantity lies loosely ahove ground, and until their true nature was discovered, a dozen years ago, were regarded a3 a great disadvantage to the land by the owners. They were detested by the farmers, like our northern drift rocks, which interfere with easy cultivation. mense area—hundreds of thousands of acres— and practically the supply may he said to hs Australian Gold Fields, The last Australian mail brings news of a dis. covery iu one of ths several miues at Ballarat, which hids fair to he of ths greatest importance the most valuable alluvial gold field in the colony. The discovery was the finding of an ex. tensive quartz recf in the claim of the Baud and Alhion Consols Compauy. The mine owned hy that company has in the past yielded grand re. turns of gold from its alluvial washes, and ths new quartz reef was found ata time when it wag worked out, The first returns ohtained from were at the rate of 12 dwt. per ton, hut they speedily improved, until 350 ounces of gold were obtained from 250 tons of quartz. The follow: ing fortnight’s crushing of stone was still hetter, 464 ounces of gold being ohtained from 176 tona of etone, and the yield for the last fortnight was 396 ouncee 12 dwt. The good effect of the discovery on the spirits of miners and those who are interested in mining property has heen mag. ical, and all the unoecupied land under which the new reef is supposed to run has heen eagerly sought after for mining purposcs. It is hoped, indeed, that Ballarat may yet prove to he as rich in auriferous quartz as it has hitherto proved in gold-hearing alluviums. The value of the discovery, so far as the claim itself is con. cerned, may be understood when it is stated that the shares of the company are now sellin at five times the price they were disposed of only ahout six weeksago. The mine is situated in Ballarat West, hut the progress of quartz mining in Ballarat East is also very satisfactory. The Queen Company, a tribute from the Black while the Sulieman Pacha has also come across a promising run of stone at the 300 level, line of reefs, and near where the celehrated Welcome nugget was found, Other claims in ie neighhorhood are also stated to be doing well. of the claims recently etarted there, and itis now prohahle that thie long-neglected field will have a chance of being thoroughly developed hy the influx of outside capital. “An alluvial gold field was found ahout three weoks ago near Dunolly, which promises to he one of the best discoveries of the new ground that has heen an: nounced for a long time past. Nuggets of various sizes, from eleven ounces downwards, have been obtained is some of the élaims at a rush, and a large numher of minere have taken up ground wherever itis thought the gold will be found, At Stawell, one of our principal quartz: miniug districts, miuing is said to he improving from the dullness which has pervaded it for the past few months. Only last week a kiln of 1,111 tons from the Oriental mine there pro: duced the splendid yield of 3,480 ozs. 11 dwts., or an average of ahout 3 ozs. 3 dwts. per tou. The company had then 600 more tons of the same kind of stone ready towards another kiln, The miners of the Pleasant Cieek Cross Reef Company, whose claim has, so far, been one of the richest worked iu the colony, believe that the resf which gave the Oriental crushing just mentioned is close to their houndary, and if that be so, the mine is likely to be very rich indeed, there is nothing of special importance recorded in connection with the other gold fields of the colony, but work, however, is carried on steadily in all of them, and itis helieved the yields are keeping up to the average. Dirrusion or Liquips.—In tho course of a recent lecture at the Royal Institution, Sir W. Thomson made some experimente to show the extreme slowness of the diffusion of liquids, He exhihited tubes filled nine days proviously, which in the upper part contained one fluid, and in the lower another, such asa eolution of sulphate of copper, a solution of common salt, colored alcohol, etc. A mark where the two fluids met was registered at the time the tuhes were filled, and in the nine days the diffusion In a lecture. filled some years ago, and from the rate of dif1,000 years. CuaRLeston PuospHates,—The rocke are of These rocks extend over an imnexhaustihle. Frencu Casie.—The cable steamer Faraday, to the future prespects of the district, hitherto thought the rich alluvial grouud was almost. the reef, which was stated to he 20 feet thick, Hill Company has struck a good hody of stone, on what is known as the Old Prince of Wales _ At Beaufort, work is proceeding on many seeming pathway acroas the surface of the great orh of day.— Albany Journal. ProspHoRESCENCE.—MM. Bancel and Husson have communicated to the Academy of Sciences observations on the phosphorescence of the flesh of the lobster. to a fermentation in which carho and phosphothe vertex helow the horizontal. The weight of . hydrogens are liberated, and which is destroyed ie 258 tbs.;. by putrefaction, just as the hacteria of carbunTo =iT2 = cleare destroyed by the vihriones of putrefaotion, They consider it due having laid the shore-end of the new French Atlantic cahle from the coast of France, has returned to England to take on board the shore: end of the cable to he laid on this side, which she will at once proceed to lay down.: ‘The telegraphic journals express considerable douhta of the financial success of this undertaking, conteuding generally that thero are already more transatlantic cables in operation than are — required for the needs of business, = ae