viously worked in the employ of Bengo, the Edinburgh house painter, before they became fellow students. He then came to London, and commenced his profession as an artist. His pictures in the public exhibitions gained favourable notice. He became Wilkie's assistant, and during twenty years worked in his studio, mostly on the still-life details of Wilkie's pictures. During this period he was frequently able to exhibit original works of his own at the Royal Academy and British Institution, at which last exhibition he obtained the premium for the best picture of the year, with his "Naainan cured of the Leprosy." This success was followed by his being made Associate of the Royal Scottish Academy, of which he had been one of the founders, and by other honours tendered by his townsmen. Commissions from some of the best patrons of the day followed, and he soon occupied a distinguished position as a painter of genre subjects. His principal works were:- Robinson Crusoe explaining the Bible to Friday," painted in 1836: and the " Interior of a Highland Cottage," painted for Mr. Vernon, and now at South Kensington. The subjects he chose were chiefly Scottish. Publications Issued. EUGENE DELACROIX.-FAC-SIMILE DE DESSINS ET CROQUIS ORIGINAUX. Par Alfred Robaut. Printed at Douai. A remarkable work, both as regards subject matter and execution. M. Robaut has well rendered the sketches of Delacroix, and his lithographic copies are as near fac-similes as possible. Not only are the strokes and touches given precisely as in the original, with here and there the notes of the artist attached, but the various colours and tints of black, white, and red chalk, sepia, pen-and-ink, and pencil, are reproduced with strict fidelity. The work is also well printed. The sketches are on folio paper, and the two series which have appeared at present include more than fifty sketches, or rather sheets, for in some cases there are more than one sketch on a sheet. Each sheet may also be purchased separately, at from two to four francs. The genius of Delacroix is so remarkable in his original sketches that these hear a higher value in proportion to his finished works than is usually the case. His daring male figures frequently call to mind some of those of Michael Angelo. Moreover, many of the sketches are the originals of ceiling decorations, which cannot be photographed, and are, in fact, much superior, in a purely artistic view, than the finished works. Notes. It PORTUGUESE INTERNATIONAL EXHIBITION.-This Exhibition of Arts, Manufactures, and Agriculture, inaugnrated by the Oporto Crystal Palace Company, is under the patronage of his Majesty Don Luiz I. and the presidency of Don Fernando of Saxe Cobourg Gotha. opens on the 21st August, and is to close on the 30th December. From the 5th to the 15th there will also be, in connection with it, an Agricultural Show of Plants and Animals. Medals and certificates of merit are to be awarded. Mr. Alfredo Allen is the Secretary at Oporto, and Messrs. W. H. Ivens and Son, Colonial Agents, Crutched-Friars, are the agents for the Oporto Crystal Palace Company in London, and will take charge of and forward goods, and represent parties there. EXHIBITION AT NICE.-A universal exposition of Horticulture, Industrial Culture, Acclimatation, and Scientific Collections, is to be held at Nice, about the 1st of May. Artistic and industrial productions will also be received. Articles may be sold at the close of the Exhibition. The Emperor gives two medals of honour -one to the foreigner or Frenchman who' most con tributes to the splendour of the Exhibition, and another to the inhabitant of the department (Alpes Maritimes) who does the same. The Empress of the French, the ladies of Nice, the Grand Duchess Helen of Russia, the Prince of Morocco, and Prince Oscar of Sweden, also offer prizes. DOG SHOW IN PARIS.-A dog show is to be held in the avenue of the Cours la Reine, in the Champs Elysées, near the Palais de l'Industrie, from the 9th to the 14th of May next, under the direction of the Zoological Society. Persons wishing to send dogs are required to make known their intention by a post-paid letter to the Director of the Zoological Society in the Bois de Boulogne, previous to the 17th April. The letter is to contain the number, the breed, and the age of the animals proposed to be exhibited. COD FISHERIES.-From the official returns relative to the French ships engaged in the cod fishery in the North Sea during the year 1864, it appears that the number of cod fish taken in 1864 was less than that in 1863the weight in 1863 being 2,240,000 kilogrammes, and in 1864 only 2,048.000 kilogrammes. On the other hand, the take of flat fish was double in 1864 to that of 1863. There was likewise a very remarkable increase in the quantity of seal oil brought home. It amounted to only 16,000 kilogrammes in 1863, and increased to 112,000 in kilogrammes in 1864. has been fearful this season in the above-named country. LOCUSTS IN SENEGAL.-The plague of these creatures Their ravages have been terrible, trees being stripped of the whole of their leaves, and shrubs and small plants being utterly destroyed. The total loss in the case of the cotton plant, which has escaped lightly, is estimated at three-fifths of the crop. In the experimental nursery grounds of the Taouey the cotton plants have been completely destroyed; not a leaf is left. the countless numbers of these insects, it is said that To give some idea of on the 19th of November last the steam dispatch-boat Archimede was moored opposite the nursery ground above mentioned, with the Governor on board, when a most extraordinary spectacle presented itself. cloud of locusts, following the course of the left bank of the Senegal river from west and east, completely hid the land from view, like a thick curtain. The insects flew at the rate of about four miles an hour, and were passing from dawn till sunset, thus forming, as it were, a column from thirty to forty miles long; but, as at sunset the cloud towards the west was much more dense than at any other period, the inference was that what had gone by was merely the avant-garde. The unfortunate cultivators are in a state of despair, while the Moors, who do not trouble themselves with agriculture, console themselves by capturing immense quantities of the locusts, which they declare to be, if not the most agreeable, at any rate the most wholesome food that can possibly be imagined. It is the converse of the old proverb, "What is one man's meat is another man's poison," or, at any rate. destruction. The locusts eat up the poor farmer's crops, and the Moor eats up the locusts, or, at any rate, a few millions of them. SUPPLY OF WATER TO PARIS.-Few cities were worse supplied with water than Paris not many years since, and still the mode of supplying is primitive, dear, and inconvenient. There is no such thing in Paris, in the ordinary way, as a huge cistern or butt from which the pail may be replenished ab libitum. Great reforms are, however, being made in this matter; a water company is gradually carrying its pipes into private houses, and the common ewer is growing rapidly in size. The means taken for increasing the supply are grand, both in conception and extent; aqueducts, canals, and artesian wells are being excavated and constructed in all quarters of the outskirts. One reservoir at Menilmontant, which is rapidly ap proaching completion, has two stages, and is destined to contain 100,000 cubic mètres of water, at the height of 108 mètres above the level of the sea, and 35,000 cubic mètres in the other compartment at 100 mètres altitude. At Belleville is another reservoir, also half finished; this is also divided into two parts, one to hold 15,000 cubic mètres, at the height of more than 134 mètres, and the other 25.000 cubic mètres, at an altitude of 131 mètres. At present one of the upper compartments is filled with Seine water raised by machinery at Charonne. The aqueduct for bringing the waters of the Dhuis to Paris is being carried on with great vigour; in the year 1863 sixteen kilomètres of canal and syphons were executed; last year ninety-six kilomètres; and only sixteen or eighteen kilomètres more remain to be accomplished, which it is expected will be done by the month of May. No work of the kind was perhaps ever performed more rapidly. Immense works are going on at Saint Maur for supplying a portion of the reservoirs and the lakes of the Bois de Vincennes; the subterranean conduits are terminated, the foundations for the machinery laid, and the buildings in hand. The lakes are expected to be supplied by these means with water from the Marne in May, and the supply of Paris with the same a month or two later. Two new artesian wells are being sunk; one of these has unfortunately fallen on a stratum of fine sand fifty-six feet thick, which has created great additional trouble, while the other has met with no serious difficulties, and is already finished down to the chalk deposits. In connection with these important works it will be interesting to give the price at which filtered water is sold by the municipal authorities to the water carriers, or other people who choose to be their own aquarii. According to a decree of the Prefect of the Seine, the price is 10 centimes for a hectolitre and a half, rather less than a penny for upwards of thirty-three gallons, and for a pailful one centime, or the tenth part of a penny. This decree came in force on the first of February. Correspondence. CANTOR LECTURES.-WATER-SUPPLY FROM WELLS.SIR, I am much obliged to Mr. Homersham for his notes of the quantity of water supplied from wells in chalk and new red sandstones. Few engineers are better qualified to give such information. In my lecture, and in the abstract published in the Journal, I rather pointed out the quantity that might be anticipated from such rocks under ordinary conditions than the exceptionally large quanties yielded by particular wells. I believe I mentioned that such exceptions occurred. Allow me to take this opportunity of correcting an error in the abstract in the second paragraph of Lecture II., referring to the water-contents of sand. In the second column of page 218, line four, the word "ten" should have been one; and in line eight, for" ten," read seventeen.--I am, D. T. ANSTted. &c., Athenæum Club, March 6. VOLUNTEER FIRE BRIGADES.-SIR,-Mr. W. Roberts, in his letter which appeared in the Journal of the Society of Arts for the 3rd instant, regrets to see his friend Mr. Young" getting into the track of underrating "the services of the regular brigade." Now, I beg to assure Mr. Roberts that I am not doing anything of the kind; that I fully appreciate the services of the regulars, give them every commendation for their exertions, and every credit for all they do; but I still maintain that they are perfectly insufficient for the work which is now required; that we have no right to ask or expect them to do it; and that we are doing wrong to leave the work to be done by those who have no obligation to perform it. As to his remarks respecting trained men, Deal boatmen, soldiers, life boats, &c., there is no necessity for a reply to them, for we know what has been done by less likely volunteers than these; but I still say, and it is constantly proved by facts, that far greater results have been, are, and will be, achieved by volunteers than by any paid men whatever; and if he says paid services are best, surely he cannot feel that he is acting in accordance with his convictions by commending and encouraging the services of a volunteer and unpaid brigade. I am, &c., CHAS. F. T. YOUNG, C.E. 7, Duke-street, Adelphi, W.C., March 7th, 1856. TAKING FISH BY SUBMARINE ILLUMINATION.-SIB,On Wednesday, the 1st inst., I attended, by invitation, at the Society of Arts, to hear a paper on the above subject. The attendance was good, and the paper interesting. I was, however, much surprised at remarks that fell from the Chairman (Sir E. Belcher); and this feeling, I think, was general, from what I heard around me. The chairman opened his address by proclaiming the prejudices that he had against our fishermen making good seamen, from their liability to be sea sick, &c. He then proceeded to relate his own surprising success as a tisherman, but could not be prevailed upon to explain the secret of it. The admiral's ideas were evidently those of the old school. I must, however, demur to his law, when he remarked that Mr. Fanshawe's patent" was of no value, as three miles out at sea it could be used with impunity." As well might the admiral say the same of Trotman's anchors, or any other patented marine invention. Probably the admiral also forgot that, unlike his own long cruises, fishing-vessels must, of necessity, frequently return to port; and the owners of those using Mr. Fanshawe's invention without his license would probably find it expensive to rely on the admiral's law with regard to patent right.-I am, &c., J. C. STOVIN. Junior Carlton Club, March 7, 1865. MEETINGS FOR THE ENSUING WEEK. R. Geographical, 81. 1. Capt. F. Galton, F.R.S., "On TUES....Medical and Chirurgical, 81. Civil Engineers, 8. Mr. J. W. Bazalgette, "On the Metropolitan System of Drainage, and the Interception of the Sewage from the River Thames." Zoological, 84. Syro-Egyptian, 7. Mr. B. H. Cowper, "A Philological Examination of certain Names of Places in the Old Testament." SESSION 1864. 507 (A. VIII.) Poor Rates and Pauperism-Return (A). 524. Local Taxations Returns-Return. Delivered on 23rd February, 1865. 30. Bills-Capital Punishments within Gaols 34. 32. 36. Bankruptcy and Insolvency (Ireland) Act Amendment. Industrial Exhibitions. 3 (70) Railway and Canal, &c. Bills-Board of Trade Reports. 27. Navy (Flogging and Marking) Returns. 48. Queen Anne's Bounty-Account. 65. Committee of Selection-First Report. 28. Court of Bankruptcy-General Return. 33. Bills-Libel. 34. Delivered on 24th February, 1865. Church Rates Commutation. 3 (71 to 78). Railway and Canal, &c. Bills-Board of Trade Reports, Parts 71 to 78. 37. Mint-Account. 41. East India (Loan)-Return. 46. Augmentation of Benefices-Summary of Return. 49. Metropolitan Improvements-Statement. 50. Army Prize Money-Account. 52. Trade and Navigation-Accounts. 54. Supply-Account. 66. Railway and Canal Bills-First Report of General Committee. Delivered on 25th and 27th February, 1865. 37. Bills-Railway Construction Facilities Act (1864) Amendment. Common Law Courts (Fees). 39. 3 (79 to 120). Railway and Canal, &c. Bills-Board of Trade Reports, Parts 79 to 120. 6. Isle of Man Disafforestation-Report. 7. Stock Certificate to Bearer-Paper. 14. Tea, Coffee, &c.-Return. 30. Assaults (Metropolis)-Return. 44. West India Islands, &c. Relief-Account. 59. Malta Docks-Papers. 65 (1). Committee of Selection-Second Report. Magnesium, manufacture of-456-J. O. Christian, and J. and H. Ordnance, breech-loading-372-A. Krupp. Oralic acid-449-F. A. Laurent, J. Cathelaz, and N. Basset. Potash and soda, sulphates and carbonates of-460-C. F. Claus. Railway carriages, signalling by the passengers to the guard of-290 Railway passengers, &c., apparatus for the protection of-472—L. W. Railway passengers, securing the safety of-454-C. Defries. Railway signalling, electro-magnetic apparatus for-488-C. V. and Railway trains, communication between passengers and guards, by Railway trains in motion, shifting points on-474-G. H. H. Ware. Sash fasteners-482-W. Hitchin. Scarfs-491-I. Pariente. Sewage, treatment of -451-R. Smith. Solid substances, extracting liquid from-486-W. E. Newton. Valve, balanced slide-496-W. E. Newton. Vessels of war, armour plates for-455-J. Brown. Volatile liquids, apparatus for distilling-447-W. E. Newton. Working ships' pumps-303-M. Blank. INVENTIONS WITH COMPLETE SPECIFICATIONS FILED. Rifle, magazine repeating and breech-loading-540-E. H. Eldredge. 66 (1). Railway and Canal Bills-Second Report of General Com- Vehicle for teaching children to walk-537-J. Askew. GRANTS OF PROVISIONAL PROTECTION. Artificial stone, manufacture of-441-W. Kirrage. Boats, ships, &c., apparatus for propelling-365-M. Bier. Books, trimming the edges of-324-W. H. and F. C. W. Latham. Boots and shoes, manufacture of-442-R. A. Brooman. Bricks, clay for the manufacture of-452-R. Hill and R. Tushingham. China and earthenware, ornamenting-435-F. J. Emery. Cylinders, apparatus for lubricating-466-T. Ogden. Drinking cup, invalid or syphon-437-R. H. Emerson. Envelopes, apparatus for folding-479-J. D. Nichol. Envelopes, fastener for-495-H. P. Ribton. Fibrous materials, preparing-376-E. Lord. Fibrous materials, spinning and carding-90-R. Tempest. Fire-arms, breech-loading, cartridge boxes for-254-E. Blakeslee. Glass, ornamented articles of-497-T. G. Webb. Highways, &c., machine for clearing, sweeping, &c.-444-H.J.Picard. Iron, manufacture of-470-W. Robinson. Iron or steel chains, making the links of-422-G. Homfray. Leather, composition as a substitute for-465-C. Brakell, W. Hoehl, Leather, &c., machinery for sewing-484-C. Baulch. Fastener and Protector for the Pin of Brooches and other similar Lid or Cover of Box Irons-Feb. 22-4694-Enoch Siddaway, West Bottle Jack-Feb. 22-4695-Farrow and Jackson, 18, Great Tower- Gas Carbonising Apparatus-Feb. 24-4696-W. Oxley and Co., St. Gentleman's Turn-down Collar-Feb. 24-4697-R. Sinclair and Co., Improved Spur Stud Socket and Plug-March 1-4698-W. Evans, Antifriction Band for Boots and Shoes-March 4-4699-W. Hallam Safety Bar for Outside Doors-March 6-4700-Walter Sandell Mappin, Birmingham. Journal of the Society of Arts, The Third Course for the present Session will consist of six Lectures "On Some of the Most Important Chemical Discoveries made within the last Two Years," to be delivered by Dr. F. F. CRACE CALVERT, F.R.S, F.C.S. (Corresponding Member of the Royal Academy of Turin; of the Société Industrielle de Mulhouse; of the Société Imperiale de Pharmacie de Paris, &c.), on Tuesday evenings, at Eight o'clock, as follows: APRIL 4TH.-LECTURE 1.-On the discoveries in Chemistry applied to Arts and Manufactures. APRIL 18TH-Lecture 2.-On the Discoveries in Chemistry applied to Arts and Manufactures (continued). APRIL 25TH.-LECTURE 3.-On the Discoveries in Agricultural Chemistry. MAY 2ND.-LECTURE 4.-On the Discoveries in Physiological Chemistry. MAY 9TH.-LECTURE 5.-On the Discoveries in the Chemistry of Rocks and Minerals. MAY 16TH-LECTURE 6.-On the Discoveries in the Chemistry of Metals and Alloys. These Lectures are free to Members (without ticket), and every Member has the privilege of admitting ONE Friend to each Lecture. MUSICAL EDUCATION. The Committee appointed by the Council to inquire into the present state of Musical Educa 304 305 [No. 643. VOL. XIII. Works in New South Wales-Salmon and Trout in Tasmania... ... 305 ... 306 Publications Issued :-Le Monde de la Mer Le Ciel Les Plantes-Le Monde des Insectes Notes:-Southern Counties Association for the Encouragement of Agriculture, Arts, Science, Manufactures, and Commerce-Renewal of Old Fruit Trees— Brome-Climate of England-Education in Russia 307 Meetings for the Ensuing Week ... tion at home and abroad, consists of the follow ing gentlemen : Wm. Hawes, Esq., Chairman of Council. Lord Henry Gordon Lennox, M.P. Lord Gerald Fitzgerald. Sir John P. Boileau, Bart. Sir George Clerk, Bart. Edgar A. Bowring, Esq., C.B. Samuel Redgrave, Esq. His Royal Highness the Prince of Wales, President of the Society, has consented to honour the Committee by acting as its chairman. Proceedings of the Society. CANTOR LECTURES. SECOND COURSE.-SIXTH LECTURE.-MONDAY, MAR. 13. MINERAL VEINS, Ores, and MINING. Professor ANSTED commenced by stating that the last division of his subject included mineral veins, their contents, and the methods adopted to extract these contents. Metals are obtained either native or as crystalline minerals, called ores, from certain fissures and veins in altered rocks. The obtaining of ores from veins is m tal mining. All rocks now above the water have been raised to their present position by some powerful upheaving force. They must have been dried before being elevated, and this involves contraction. Contraction and elevation must have produced cracks and fractures, whose nature depends partly on the rock itself, and partly on the mode of action of the moving force. It is not possible to conceive upheavals without fissures; but they are of two kinds, as due to two causes. Those caused by contraction will be governed by chemical laws. Those caused by upheaval will be regulated by the amount of force exerted, the weight to be lifted, the direction of the upheaving force, and the mechanical condition of the rock at the time of up heaval. The first kind may have begun as soon as the on yielding, and these cracks will follow certain laws. rock existed. The second kind commenced with the first They must be parallel and at right angles to each other upheaval. They may be due to a multitude of move- and to the elevating force. One important conclusion ments going on for a long time. During long periods from this mode of considering mineral veins is, that in such fissures may have remained unaltered. From time to different countries the systems of veins must exhibit diftime they may have been interfered with by other fissures. ferent directions. Thus, while the ore-bearing veins in But cracks once formed, and then neglected, may have Cornwall are east and west, in other districts they may been filled up with fragments of the adjacent rock, or with be north and south. The direction of elevation must gocrystals that have grown in the cavity. A crack in a vern the formation of each system of veins. But if veins A are due to disturbances that have acted at intervals during mass of limestone may be occupied with cale spar. wide fissure in such rock may be filled with rolled blocks a long period of time, and not always in the same direcof limestone. An empty space may have become filled tion, the axis of disturbing forces may change, and there All rocks present phe- may be new systems of veins crossing older systems. Or with lumps of zinc or lead ore. nomena that have some resemblance to those of mineral successive elevations may produce complication in a difveins; the formation is an ordinary event in nature. ferent way, breaking up and heaving the mineral veins Crevices formed during the elaboration of a rock, are small, after they have been filled. Thus are produced faults and and filled up with crystalline material derived from the rock throws. In the determination of the law that governs itself. The rook is purged of foreign contents by aid of the distribution of lodes, we should know the direction of these cracks, and by the facilities they offer for throwing the axes of elevation that have effected them, and the off substances of which there is only a small proportion, order of the occurrence of the disturbance. The fissures But the filling up of crevices formed by contraction need formed in rocks, whether on solidifying or whilst elevanot differ from the filling of wider cracks. The crevice tion was going on, must approximate rather to a vertical must be formed before the filling up can begin, and thus than horizontal direction. Thus mineral veins are often every true crack must have defined walls. This distin- almost vertical, or if inclined they are so slightly and guishes true veins from differences of condition and of irregularly. But fissures in rocks are not lodes until they The filling up distinguishes the mineral mineral composition which belong to some process of se- have been filled with mineral matters. These are usually gregation. The successive veins in slates and granites, crystalline. elvans, bands in clays, and coloured lines and marks in vein from the open fault, or crevice, and the lode from sandstones, are of this nature. They are modifications of the mineral vein. There is no reason why a fissure open the rock, but not mineral veins. Of the two classes of at the top, or a crack formed during the construction of fissures those produced during the formation of the rock an ordinary fault, should not become filled with stones All fissures in from above or from the walls. Occasionally the vein conare the simpler and the most common. rocks, filled with crystalline minerals may be called tains substances washed in by water from a distance. But mineral veins, but only those which contain valuable ores when mineral veins are filled with spar the case is difIn this way some veins are lodes or metalliferous veins. The origin of the vein ferent. The material may have been carried in from is of small importance, but its history is interesting, and above and deposited from water. will guide the miner in following the traces of the vein iu limestone contained in a solid mass angular and rolled when it is lost sight of. Metalliferous veins in stratified lumps of limestone, galena, blende, calamine, and shells. So it is possible that crevices open below rocks are chiefly confined to accumulations of lead and The cementing medium is carbonate of lime, and the zine ore and carbonate of iron in natural open spaces or agent water. caverns in limestone. It is difficult to explain this, but have received minerals in the state of vapour. Of these In volcanic disit is a law of nature, at least with certain limitations. sulphur and arsenic are familiar examples. The former Thus deposits from Let us see what these veins are like, and what clue we is found lining the walls of cavities. Between and amongst tricts examples of this are common. can obtain to their history, limestones, where the bedding is regular, and cavities above, brought in with or without water, and deposits occur at the interval between two beds, there may be from below, with or without steam, are methods adopted These cavities com- by nature. But no one familiar with veins will suppose deposits of galena and calamine. municate with others by crevices across and between that all known cases can be thus explained. The vast the strata. How far the natural cracks may have beer majority of lodes are lined with crystalline minerals enlarged by subsequent upheaval, it is impossible which have commenced to form on each wall of the vein, to say, but the main deposits of ore often seem de- and not either at the top or lower part. When the dependent on the stratification. There is little guide to posit has begun, the crystals have accumulated symmetrithe discovery of veins of this kind when lost, beyond a cally. Assuming that crevices have become converted careful following of the clue afforded by a thread of ore. into veins by chemical action within the rock, this either Useful mineral veins are the result of disturbances that involves the conveyance of foreign material by water circuare systematic, and they often correspond with the struc- lating through the veins, or the passage of this foreign Thus, material through the mass of the rock itself. Both are ture of the part of the country where they occur. in Cornwall and Devon there is a chain of granite bosses possible. Water circulates through all free spaces in the ranging east and west, and a quantity of slates, schists, interior of the earth. It is often hot, and loaded with a &c., having a similar range. In the slates, schists, and variety of minerals. Hot water no doubt has been largely granite are numerous metalliferous veins. Of these some concerned in bringing various ores as well as earthy Such minerals into veins. The filling up of veins is a subject are more regular, and better defined than the rest. veins are called master lodes or champion lodes. They of the deepest interest to the miner. He would willingly are parallel to each other, and may be recognized as be discover a law by which he could convince himself of the longing to a system. These main lodes range in the existence of ore from the nature of the surrounding rocks, same direction as the axis of elevation of the district. or from the surface appearance of the lode, or from the The general range of the local geological axis of the intersections of lodes with each other, or with some parcountry being made out, then the direction of the main ticular kind of rock; or from the degree of inclination lodes are parallel to it, and the lodes of next importance of the lode. Such laws are not known, and it will be at right angles to it. And this law is an expression of long before observations on these conditions justify absothe fact that mineral veins are fissures in altered rocks, lute conclusions. But there is some relation between the produced systematically by mechanical force elevating the contents of a lode and the conditions under which it has whole district, and breaking up the rocks in a manner become filled. By observing facts, and studying their that may be estimated mathematically. If a rigid solid, mutual relations, miners have found that a gossan or iron The condition of the gossan is significant, tied down on all sides, be exposed to pressure from below, oxide at the top of a lode is an indication of a course sufficient to overcome the tension of its parts, it must crack of ore. |