,,the ,,industrial ,,readers ,book ,,ii ,,diggers ,,in ,,the ,,earth ,,by ,,eva ,,march ,,tappan1 ,ph4,d4 ,author of ,england's ,story1 ,american ,hero ,stories1 ,old ,world ,hero ,stories1 ,story of the ,greek ,people1 ,story of the ,roman ,people1 etc4 ,editor of ,the ,children's ,hour4 ,illustration ,,houghton ,,mifflin ,,company ,,boston ,,new ,,york ,,chicago ,,the ,,industrial ,,readers ,by ,eva ,march ,tappan ,i4 ,,the ,,farmer ,,and ,,his ,,friends4 #ej cents4 ,,ii4 ,,diggers ,,in ,,the ,,earth4 #ej cents4 ,,iii4 ,,makers ,,of ,,many ,,things4 #ej cents4 ,,iv4 ,,travelers ,,and ,,traveling4 #ej cents4 ,the foregoing are list prices1 postpaid ,,copyright1 #aiaf1 ,,by ,,eva ,,march ,,tappan ,,all ,,rights ,,reserved ,first printing ,april #aiaf2 ,reprinted ,december #aiaf ,the ,riverside ,press ,,cambridge1 ,,massachusetts ,u4 ,s4 ,a4 ,,preface ,the four books of this series have been written not merely to provide agreeable reading matter for children1 but to give them information4 ,when a child can look at a steel pen not simply as an article furnished by the city for his use1 but rather as the result of many interesting processes1 he has made a distinct growth in intelligence4 ,when he has begun to apprehend the fruitfulness of the earth1 both above ground and below1 and the best way in which its products may be utilized and carried to the places where they are needed1 he has not only acquired a knowledge of many kinds of industrial life which may help him to choose his life-work wisely from among them2 but he has learned the dependence of one person upon other persons1 of one part of the world upon other parts1 and the necessity of peaceful intercourse4 ,best of all1 he has learned to see4 ,wordsworth's familiar lines say of a man whose eyes had not been opened1-- ,a primrose by a river's brim ,a yellow primrose was to him1 ,and it was nothing more4 ,these books are planned to show the children that there is something more2 to broaden their horizon2 to reveal to them what invention has accomplished and what wide room for invention still remains2 to teach them that reward comes to the man who improves his output beyond the task of the moment2 and that success is waiting not for him who works because he must1 but him who works because he may4 ,acknowledgment is due to the ,lehigh ,valley ,railroad1 ,jones ,brothers ,company1 ,alpha ,portland ,cement ,company1 ,dwight ,w4 ,woodbridge1 the ,utah ,copper ,company1 the ,aluminum ,company of ,america1 the ,diamond ,crystal ,salt ,company1 ,t4 ,w4 ,rickard1 and others1 whose advice and criticism have been of most valuable aid in the preparation of this volume4 ,,eva ,,march ,,tappan4 ,,contents ,i4 ,,in ,a ,,coal ,,mine #a ,,ii4 ,,down ,,in ,,the ,,quarries #aa ,,iii4 ,,houses ,,of ,,sand #ba ,,iv4 ,,bricks1 ,,their ,,faults ,,and ,,their ,,virtues #ca ,v4 ,,at ,,the ,,gold ,,diggings #ci ,,vi4 ,,the ,,story ,,of ,a ,,silver ,,mine #dh ,,vii4 ,,iron1 ,,the ,,everyday ,,metal #eg ,,viii4 ,,our ,,good ,,friend ,,copper #fe ,,ix4 ,,the ,,new ,,metal1 ,,aluminum #gf ,x4 ,,the ,,oil ,,in ,,our ,,lamps #hd ,,xi4 ,,little ,,grains ,,of ,,salt #ie ,,list ,,of ,,illustrations ,a ,,structural ,,steel ,,apartment ,,building vi ,,how ,a ,,coal ,,mine ,,looks ,,aboveground #e ,,miners ,,and ,,their ,,mine #aj ,,opening ,a ,,granite ,,quarry #ac ,,building ,a ,,concrete ,,road #bg ,,in ,a ,,new ,,jersey ,,brick ,,mill #cc ,,hydraulic ,,gold ,,mining #da ,,the ,,story ,,of ,a ,,spoon #ea ,,in ,,the ,,steel ,,foundry #fa ,,in ,a ,,copper ,,smelter #fg ,a ,,movie ,,of ,,an ,,aluminum ,,funnel #gi ,a ,,california ,,oil ,,field #hg ,illustration3 ,a ,,structural ,,steel ,,apartment ,,building ,courtesy ,american ,bridge ,co4 ,first the steel frame1 then the floors1 then the stone or brick shell1 then the interior finishing--this is how the building is made4 ,,the ,,industrial ,,readers ,,book ,,ii ,,diggers ,,in ,,the ,,earth ,i ,,in ,a ,,coal ,,mine ,did you ever wonder how beds of coal happened to be in the earth8 ,this is their story4 ,centuries ago1 so many thousand centuries that even the most learned men can only guess at their number1 strange things were coming to pass4 ,the air was so moist and cloudy that the sun's rays had hard work to get through4 ,it was warm1 nevertheless1 for the crust of the earth was not nearly so thick as it is now1 and much heat came from the earth itself4 ,many plants and trees grow best in warm1 moist air2 and such plants flourished in those days4 ,some of their descendants are living now1 but they are dwarfs1 while their ancestors were giants4 ,there is a little horse-tail growing in our meadows1 and there are ferns and club mosses almost everywhere4 ,these are some of the descendants2 but many of their ancestors were forty or fifty feet high4 ,they grew very fast1 especially in swamps2 and when they died1 there was no lack of others to take their places4 ,dead leaves fell and heaped up around them4 ,stumps stood and decayed1 just as they do in our forests to-day4 ,every year the soft1 black1 decaying mass grew deeper4 ,as the crust of the earth was so thin1 it bent and wrinkled easily4 ,it often sank in one place and rose in another4 ,when these low1 swampy places sank1 water rushed over them1 pressing down upon them with a great weight and sweeping in sand and clay4 ,now1 if you burn a heap of wood in the open air1 the carbon in the wood burns and only a pile of ashes remains4 ,burning means that the carbon in the wood unites with the oxygen gas in the air4 ,if you cover the wood before you light it1 so that only a little oxygen reaches it1 much of the carbon is left1 in the form of charcoal4 ,when wood decays1 its carbon unites with the oxygen of the air2 and so decay is really a sort of burning4 ,in the forests of to-day the leaves1 and at length the trees themselves1 fall and decay in the open air2 but at the time when our coal was forming1 the water kept the air away1 and much carbon was left4 ,this is the way coal was made4 ,some of the layers1 or strata1 are fifty or sixty feet thick1 and some are hardly thicker than paper4 ,on top of each one is a stratum of sandstone or dark-gray shale4 ,this was made by the sand and mud which were brought in by the water4 ,these shaly rocks split easily into sheets and show beautiful fossil impressions of ferns4 ,there are also impressions of the bark and fruit of trees1 together with shells1 crinoids1 corals1 remains of fishes and flying lizards1 and some few trilobites1--crablike animals with a shell somewhat like the back of a lobster1 but marked into three divisions or lobes1 from which its name comes4 ,since the crust of the earth was so thin and yielding1 it wrinkled up as the earth cooled1 much as the skin of an apple wrinkles when the apple dries4 ,this brought some of the strata of coal to the surface1 and after a while people discovered that it would burn4 ,if a vein of coal cropped out on a man's farm1 he broke some of it up with his pickaxe1 shoveled it into his wheelbarrow1 and wheeled it home4 ,after a while hundreds of thousands of people wanted coal2 and now it had to be mined4 ,in some places the coal stratum was horizontal and cropped out on the side of a hill1 so that a level road could be dug straight into it4 ,in other places the coal was so near the surface that it could be quarried under the open sky1 just as granite is quarried4 ,generally1 however1 if you wish to visit a coal mine1 you go to a shaft1 a square1 black well sometimes deeper than the height of three or four ordinary church steeples4 ,you get into the cage1 a great steel box1 and are lowered down1 down1 down4 ,at last the cage stops and you are at the bottom of the mine4 ,the miners' faces1 hands1 overalls1 are all black with coal dust4 ,they wear tiny lamps on their caps1 and as they come near the walls of coal1 it sparkles as it catches the light4 ,here and there hangs an electric lamp4 ,it is doing its best to give out light1 but its glass is thick with coal dust4 ,the low roof is held up by stout wooden timbers and pillars of coal4 ,a long passageway stretches off into a blacker darkness than you ever dreamed of4 ,suddenly there is a blaze of red light far down the passage1 a roar1 a medley of all sorts of noises1--the rattling of chains1 the clattering of couplings1 the shouts of men1 the crash of coal falling into the bins4 ,it is a locomotive dragging its line of cars loaded with coal4 ,in a few minutes it rushes back with empty cars to have them refilled4 ,all along this passageway are rooms1 that is1 chambers which have been made by digging out the coal4 ,above them is a vast amount of earth and rock1 sometimes hundreds of feet in thickness4 ,there is always danger that the roof will cave in1 and so the rooms are not made large1 and great pillars of coal are left to hold up the roof4 ,not many years ago the miner used to do all the work with his muscles2 now machines do most of it4 ,the miner then had to lie down on his side near the wall of coal in his room and cut into it1 close to the floor1 as far as his pickaxe would reach4 ,then he bored a hole into the top of the coal1 pushed in a cartridge1 thrust in a slender squib1 lighted it1 and ran for his life4 ,the cartridge exploded1 and perhaps a ton or two of coal fell4 ,the miner's helper shoveled this into a car and pushed it out of the room to join the long string of cars4 ,illustration3 ,,how ,a ,,coal ,,mine ,,looks ,,aboveground ,all that shows on the surface is the machinery shed where the various engines work to keep the air fresh1 and bring up the miners and the coal4 ,that is the way mining used to be done4 ,in these days a man with a small machine for cutting coal comes first4 ,he puts his cutter on the floor against the wall of coal and turns on the electricity4 ,chip1 chip1 grinds the machine1 eating its way swiftly into the coal1 and soon there is a deep cut all along the side of the room4 ,the man and his machine go elsewhere1 and the first room is left for its next visitors4 ,they come in the evening and bore holes for the blasting4 ,once these holes were bored by hand1 but now they are made with powerful drills that work by compressed air4 ,a little later other men come and set off cartridges4 ,in the morning when the dust has settled and the smoke has blown away1 the loaders appear with their shovels and load the coal into the cars4 ,then it is raised to the surface and made ready for market4 ,did you ever notice that some pieces of coal are dull and smutty1 while others are hard and bright8 ,the dull coal is called bituminous1 because it contains more bitumen or mineral pitch4 ,this is often sold as run-of-mine coal1--that is1 just as it comes from the mine1 whether in big pieces or in little ones2 but sometimes it is passed over screens1 and in this process the dust and smaller bits drop out4 ,the second kind of coal1 the sort that is hard and bright1 is anthracite4 ,its name is connected with a ,greek word meaning ruby4 ,it burns with a glow1 but does not blaze4 ,most of the anthracite coal is used in houses1 and householders will not buy it unless the pieces are of nearly the same size and free from dirt1 coal dust1 and slate4 ,the work of preparation is done in odd-shaped buildings called breakers4 ,one part of a breaker is often a hundred or a hundred and fifty feet in height4 ,the coal is carried to the top of the breaker4 ,from there it makes a journey to the ground1 but something happens to it every little way4 ,it goes between rollers1 which crush it2 then over screens1 through which the smaller pieces fall4 ,sometimes the screens are so made that the coal will pass over them1 while the thin1 flat pieces of slate will fall through4 ,in spite of all this1 bits of coal mixed with slate sometimes slide down with the coal1 and these are picked out by boys4 ,a better way of getting rid of them is now coming into use4 ,this is to put the coal and slate into moving water4 ,the slate is heavier than the coal1 and sinks2 and so the coal can easily be separated from it4 ,dealers have names for the various sizes of coal4 ,egg must be between two and two and five eighths inches in diameter2 nut between three fourths and one and one eighth inches2 pea between one half and three fourths of an inch4 ,mining coal is dangerous work4 ,any blow of the pickaxe may break into a vein of water which will burst out and flood the mine4 ,the wooden props which support the roof may break1 or the pillars of coal may not be large enough2 and the roof may fall in and crush the workers4 ,there are always poisonous gases4 ,the coal1 as has been said before1 was made under water1 and therefore the gas which was formed in the decaying leaves and wood could not escape4 ,it is always bubbling out from the coal1 and at any moment a pickaxe may break into a hole that is full of it4 ,one kind of gas is called choke-damp1 because it chokes or suffocates any one who breathes it4 ,there is also white-damp1 the gas which you see burning with a pretty blue flame over a hot coal fire4 ,worst of all is the fire-damp4 ,if you stir up the water in a marsh1 you will see bubbles of it rise to the surface4 ,it is harmless in a marsh1 but quite the opposite in a mine4 ,when it unites with a certain amount of air1 it becomes explosive1 and the least bit of flame will cause a terrible explosion4 ,even coal dust may explode if the air is full of it1 and it is suddenly set in motion by too heavy a blast of powder4 ,miners used to work by candlelight4 ,every one knew how dangerous this was2 but no one found any better way until1 about a hundred years ago1 ,sir ,humphry ,davy noticed something which other people had not observed4 ,he discovered that flame would not pass through fine wire gauze1 and he made a safety lamp in which a little oil lamp was placed in a round funnel of wire gauze4 ,the light1 but not the flame1 would pass through it2 and all safety lamps that burn oil have been made on this principle4 ,the electric lamp1 however1 is now in general use4 ,the miner wears it on his cap1 and between his shoulders he carries a small1 light storage battery4 ,even with safety lamps1 however1 there are sometimes explosions4 ,the only way to make a mine at all safe from dangerous gases is to keep it full of fresh1 pure air4 ,there is no wind to blow through the chambers and passages1 and therefore air has to be forced in4 ,one way is to keep a large fire at the bottom of the air shaft4 ,if you stand on a stepladder1 you will feel that the top of the room is much warmer than the floor4 ,this is because hot air rises2 and in a mine1 the hot air over the fire rises and sucks the foul air and gas out of the mine1 and fresh air rushes in to take its place4 ,another way is by a fan1 a machine that forces fresh air into the mine4 ,illustration3 ,,miners ,,and ,,their ,,mine ,notice the safety lamps in the men's caps1 and the little railroad on which the cars of coal and ore travel1 hauled by the useful mule4 ,so it is that by hard work and much danger we get coal for burning4 ,now1 coal is dirty and heavy4 ,a coal fire is hard to kindle and hard to put out1 and the ashes are decidedly disagreeable to handle4 ,and after all1 we do not really burn the coal itself1 but only the gas from it which results from the union of carbon and oxygen4 ,in some places natural gas1 as it is called1 which comes directly from some storehouse in the ground1 is used in stoves and furnaces and fireplaces for both heating and cooking2 and perhaps before long gas will be manufactured so cheaply and can be used so safely and comfortably that we shall not have to burn coal at all1 but can use gas for all purposes--unless electricity should take its place4 ,,ii ,,down ,,in ,,the ,,quarries ,when walking in the country one day ,i came to a beautiful pond by the side of the road4 ,the water was almost as clear as air1 and as ,i looked down into it1 ,i could see that the bottom was made of granite4 ,the farther shores were cliffs of clean granite thirty or forty feet high and coming down to the water's edge4 ,the marks of tools could be seen on them1 showing where blocks of stone had evidently been split off4 ,i picked up a piece of the rock and examined it closely4 ,it proved to be made up of three kinds of material4 ,first1 there were tiny sparkling bits of mica4 ,in some places there are mica mines yielding big sheets of this curious mineral which is used in the doors of stoves and the little windows of automobile curtains4 ,with the point of a knife the bits in my piece of granite could be split into tiny sheets as thin as paper4 ,the second material was quartz4 ,this was grayish-white and looked somewhat like glass4 ,the third material was feldspar4 ,this1 too1 was whitish1 but one or two sides of each bit were flat1 as if they had not been broken1 but split4 ,this is the most common kind of granite4 ,there are many varieties4 ,some of them are almost white1 some dark gray1 others pale pink1 and yet others deep red4 ,it is found in more than half the ,states of the ,union4 ,this quarry had been given up and allowed to fill with water2 but it was a granite country1 and farther down the road there was another1 where scores of men were hard at work4 ,this second quarry was part-way up a hill2 or rather1 it was a hill of granite which men were digging out and carrying away4 ,when they began to open the quarry1 much of the rock was covered with dirt and loose stones1 and even the granite that showed aboveground was worn and broken and stained4 ,this is called trap rock4 ,the easiest way to get rid of it is to blast with dynamite and then carry away the dirt and fragments4 ,next comes the getting out of great masses of rock to use1 some of them perhaps long enough to make the pillars of a large building4 ,illustration3 ,,opening ,a ,,granite ,,quarry ,courtesy ,jones ,brothers ,company4 ,the first thing to do is to strip off the soil from the stone4 ,then1 as the blocks are cut out1 the big derrick lifts and loads them on waiting cars4 ,now1 granite is a hard stone1 but there is no special difficulty in cutting it if you know how4 ,in the old days1 when people wished to split a big boulder1 they sometimes built a fire beside it1 and when it was well heated1 they dropped a heavy iron ball upon it4 ,king's ,chapel in ,boston was built of stone broken in this way4 ,to break from a cliff1 however1 a block of granite big enough to make a long pillar is a different matter1 and this is what the men were doing4 ,first of all1 the foreman had examined the quarry till he had found a stratum of the right thickness4 ,he had marked where the ends were to come1 and the men had drilled holes down to the bottom of the stratum4 ,then he had drawn a line at the back along where he wished the split to be1 and the men had drilled on this line also a row of holes4 ,next came the blasting4 ,if one very heavy charge had been exploded1 it would probably have shattered the whole mass1 or at any rate have injured it badly4 ,instead of this1 they put into each hole a light charge of coarse powder and covered it with sand4 ,these were all fired at the same instant1 and thus the great block was loosened from the wall4 ,sometimes there seems to be no sign of strata1 and then a line of horizontal holes must be drilled where the bottom of the block is to be4 ,after this comes what is called the plug-and-feather process4 ,into each hole are placed two pieces of iron1 shaped like a pencil split down the middle4 ,these are the feathers4 ,the plug is a small steel wedge that is put between the iron pieces4 ,then two men with hammers go down the line and strike each wedge almost as gently as if it was a nut whose kernel they were afraid of crushing4 ,they go down the line again1 striking as softly as before4 ,then1 if you look closely1 you can see a tiny crack between the holes4 ,there is more hammering1 the crack stretches farther1 a few of the wedges are driven deeper and the others drop out4 ,the block splits off4 ,a mighty chain is then wound about it1 the steam derrick lifts it1 lays it gently upon a car1 and it is carried to the shed to be cut into shape1 smoothed1 and perhaps polished4 ,in almost every kind of work new methods are invented after a while4 ,in quarrying1 however1 the same old methods are in use4 ,the only difference is that1 instead of the work being done by muscle1 it is done by compressed air or steam or electricity4 ,compressed air or steam works the drill and the sledgehammer4 ,the drill is held by an arm1 but the arm is a long steel rod which is only guided by the workman4 ,not the horse-sweep of old times1 but the steam derrick and the electric hoist lift the heavy blocks from the quarry4 ,polishing used to be a very slow1 expensive operation1 because it was all done by the strength of some one's right arm1 but now1 although it takes as much work as ever1 this work is done by machinery4 ,to point a piece of stone1 or give it a somewhat smooth surface1 is done now with tools worked by compressed air4 ,after this1 the stone is rubbed--by machinery1 of course--with water and emery1 then by wet felt covered with pumice or polishing putty4 ,a few years ago two young ,vermonters invented a machine that would saw granite4 ,this saw has no teeth1 but only blades of iron4 ,between these blades and the piece of granite1 however1 shot of chilled steel are poured2 and they do the real cutting4 ,granite has long been used in building wherever a strong1 solid material was needed2 but until the sand blast was tried1 people thought it impossible to do fine work in this stone4 ,there was a firm in ,vermont1 however1 who believed in the sand blast4 ,they had a contract with the ,government to furnish several thousand headstones for national cemeteries4 ,cutting the names would be slow and costly2 so they made letters and figures of iron1 stuck them to the stones1 and turned on the blast4 ,if a sand blast is only fast enough1 it will cut stone harder than itself4 ,the blast was turned upon a stone for five minutes4 ,then the iron letters were removed4 ,there stood in raised letters the name1 company1 regiment1 and rank of the soldier1 while a quarter of an inch of the rest of the stone1 which the iron letters had not protected1 had been cut away4 ,by means of the sand blast it has become possible to do beautiful carving even in material as hard as granite4 ,granite looks so solid that people used to think it was fireproof2 but it is really poor material in a great fire4 ,most substances expand when they are heated2 but the three substances of which granite is made do not expand alike1 and so they tend to break apart and the granite crumbles4 ,a marble quarry is even more interesting than a granite quarry4 ,if you stand on a hill in a part of the country where marble is worked1 you will see white ledges cropping out here and there4 ,the little villages are white because many of the houses are built of marble4 ,then1 too1 there are great marble quarries flashing in the sunshine4 ,sometimes a marble quarry is chiefly on the surface4 ,sometimes the marble stretches into the earth1 and the cutting follows it until a great cavern is made1 perhaps two or three hundred feet deep4 ,a roof is often built to keep out the rain and snow4 ,it keeps out the light1 too1 and on rainy days the roof1 together with the smoke and steam of the engines1 makes the bottom of the quarry a gloomy place4 ,everywhere there are slender ladders with men running up and down them4 ,there are shouts of the men1 clanking of chains1 and puffing of locomotives4 ,marble is cut out in somewhat the same way as granite1 but a valuable machine called a channeler is much used4 ,this machine runs back and forth1 cutting a channel two inches wide along the ends and back and sometimes the bottom of the block to be taken out4 ,marble is so much softer than granite that it is far more easy to work4 ,cutting it is a simple matter4 ,the saw1 which is a smooth flat blade of iron1 swings back and forth1 while between it and the marble sand and water are fed4 ,it does not exactly cut1 but rubs1 its way through4 ,the round holes in the tops of washstands are cut by saws like this1 only bent in the form of a cylinder and turned round and round1 going in a little deeper at each revolution4 ,a queer sort of saw is coming into use4 ,it is a cord made of three steel wires twisted loosely together4 ,this cord is stretched tightly over pulleys and moves very rapidly4 ,every little ridge of the cord strikes the stone and cuts a little of it away4 ,there are varieties of marble without end4 ,the purest and daintiest is the white of which statues are carved2 but there are black1 red1 yellow1 gray1 blue1 green1 pink1 and orange in all shades4 ,many are beautifully marked4 ,the inner walls of buildings are sometimes covered with thin slabs of marble4 ,these are often carefully split1 and the two pieces put up side by side1 so that the pattern on one is reversed on the other4 ,certain kinds of marble contain fossils or remains of coral and other animals that lived hundreds of thousands of years ago4 ,in some marbles there are so many that the stone seems to be almost made of them4 ,when a slab is cut and polished1 the fossils are of course cut into2 but even then we can sometimes see their shape4 ,one of the most common is the crinoid4 ,this was really an animal1 but it looked somewhat like a closed pond lily with a long stem1 and people used to call it the stone lily4 ,this stem is made up of little flat rings looking like bits of a pipestem4 ,the stems are often broken up and these bits are scattered through the marble4 ,the animals whose shells help to make marble lived in the ocean1 and when they died sank to the bottom4 ,many of the shells were broken by the beating of the waves1 but both broken shells and whole ones became united and hardened into limestone1 one kind of which we call marble4 ,common chalk is another kind4 ,blackboard crayons are made of this3 so are whitewash and whiting for cleaning silver and making putty4 ,another stone that builders would be sorry to do without is slate4 ,this1 too1 was formed at the bottom of the sea4 ,rivers brought down fine particles of clay1 which settled1 were covered by other matter1 and finally became stone4 ,it was formed in layers1 of course1 but1 queerly enough1 it splits at right angles to its bottom line4 ,just why it does this is not quite certain1 but the action is thought to be due to heat and long1 slow pressure1 which will do wonderful things1 as in the case of coal4 ,this splitting is a great convenience for the people who want to use it for roofing and for blackboards4 ,blocks of slate are loosened by blasting1 and are taken to the splitting-shed4 ,splitting slate needs care1 and a man who is not careful should never try to work in a slate quarry4 ,the splitting begins by one man's dividing the block into pieces about two inches thick and somewhat larger than the slates are to be when finished4 ,the way he does this is to cut a little notch in one end of the block with his sculpin chisel and make a groove from this across the block4 ,he must then set his chisel into the groove1 strike it with a mallet1 and split the slate to the bottom4 ,this sounds easy1 but it needs skill4 ,slate has sometimes its own notions of behavior1 and it does not always care to split in a straight line exactly perpendicular to the bottom of the stratum4 ,the man keeps it wet so that he can see the crack more plainly1 and if that crack turns back a little to the right1 he must turn it to the left by striking the sculpin toward the left1 or perhaps by striking a rather heavy blow on the left of the stone itself4 ,now the chief splitter takes it1 and with a broad thin chisel he splits it into plates becoming thinner at each split4 ,the second assistant trims these into the proper shape and size with either a heavy knife or a machine4 ,slate can be sawed and planed2 but whatever is done to it should be done when it first comes from the quarry1 for then it is not so likely to break4 ,it would be very much cheaper if so much was not broken and wasted at the quarries and in the splitting4 ,it is said that in ,wales sometimes one hundred tons of stone are broken up to get between three and four tons of good slate4 ,within the last few years the quarrymen have been using channeling machines and getting out the slate in great masses instead of small blocks4 ,this is not so wasteful by any means2 but even now there is room for new and helpful inventions4 ,,iii ,,houses ,,of ,,sand ,if you wanted to build a house1 of what should you build it8 ,in a new country1 people generally use wood2 but after a time wood grows expensive4 ,moreover1 wood catches fire easily2 therefore1 as a country becomes more thickly settled and people live close together in cities1 stone and brick are used4 ,large cities do not allow the building of wooden houses within a certain distance from the center1 and sometimes even the use of wooden shingles is forbidden4 ,of late years large numbers of concrete or cement houses have been built4 ,our grandfathers would have opened their eyes wide at the suggestion of a house built of sand1 and would have felt anxious at every rainfall lest their homes should suddenly melt away4 ,even after thousands of concrete buildings were in use1 many people still feared that they would not stand the cold winters and hot summers of the ,united ,states2 but it has been proved that concrete is a success provided it is properly made4 ,no one can succeed in any work unless he understands how it should be done4 ,concrete is made of ,portland cement1 mixed with sand and water and either broken stone1 gravel1 cinders1 or slag2 but if any one thinks that he can mix these together without knowing how and produce good concrete1 he will make a bad mistake rather than a good building material4 ,first1 he must buy ,portland cement of the best quality4 ,this cement is made of limestone and clay1 or marl1 chalk1 and slag4 ,these are crushed and ground and put into a kiln which is heated up to #bejj deg4 or #cjjj deg4,f42 that is1 from twelve to fourteen times as hot as boiling water4 ,the stone fuses sufficiently to form a sort of clinker4 ,after this has cooled1 it is ground so fine that the greater part of it will pass through a sieve having #dj1jjj meshes to the square inch4 ,to every hundred pounds of this powder1 about three pounds of gypsum is added4 ,the mixture is then put into the bags in which we see it for sale in the stores4 ,this powder is so greedy for water that it will absorb the moisture from the air around it4 ,even in the bags1 it begins to harden as soon as it gets some moisture2 and as soon as it hardens1 it is of no use4 ,the moral of that is to keep your cement in a dry place4 ,the second substance needed in concrete is broken stone or gravel4 ,of course a hard rock must be selected1 such as granite or trap rock4 ,limestone calcines in a heat exceeding #ajjj deg4 ,f41 and therefore it cannot be used in fireproof construction4 ,soft rock1 like slate or shale or soft sandstone1 will not answer because it is not strong enough4 ,gravel is always hard4 ,if you look at a cut in a gravel bank1 you will usually see strata of sand and then strata of rounded pebbles of different sizes4 ,the sand was once an ancient sea beach2 the pebbles were dashed up on it by waves or storms or some change of currents4 ,they were at first only broken bits of rock1 but after being rolled about for a few thousand years in the ocean and on the shore1 the corners were all rounded4 ,soft rock would have been ground to powder by such treatment4 ,sometimes1 if there is to be no great strain on the concrete1 cinders or pieces of brick may be used instead of stone2 and for some purposes they answer very well4 ,the third substance used in concrete is sand2 but it must be the right kind of sand1 having both fine and coarse grains4 ,these grains need to be sharp1 or the cement will not stick to them well4 ,they must also be clean1 that is1 free from dirt4 ,if you rub sand between your hands1 and it soils them1 then there is clay or loam with it1 and it must not be used in making concrete unless it is thoroughly washed4 ,another way of testing it is to put it into a glass jar partly full of water and shake it4 ,then let it settle4 ,if there is soil in the sand1 it will appear as a stratum of mud on top of the sand4 ,the water with which these three substances are to be mixed must be clean and must contain no acid and no strong alkali4 ,as a general rule1 there must be twice as much broken stone as sand4 ,when people first make concrete1 they often expect too much of their materials4 ,a good rule for the strongest sort of cement1 strong enough for floors on which heavy machines are to stand1 is one fourth of a barrel of cement1 half a barrel of sand1 and one barrel of gravel or broken stone4 ,apparently this would make one and three fourths barrels2 but in reality it makes only about one barrel1 because the sand fills in the spaces between the gravel1 and the cement fills in the spaces between the grains of sand4 ,there are many sorts of machines on the market for mixing the materials2 but small quantities can just as well be mixed by hand4 ,the mixing-bowl is a platform1 and on this the sand is laid4 ,then comes the cement2 and these two must be shoveled together several times4 ,while this is being done1 the broken stone or gravel must be wet1 and now it is put on top of the sand and cement and well shoveled together1 with just enough water added so that the mass will almost bear the weight of a man4 ,concrete is impatient to be hardening1 and if it is not put into the right place1 it will begin promptly to harden in the wrong place1 and nothing can be done with it afterwards4 ,if it is to be made in blocks1 the moulds must be ready and the concrete put into them at once and well tamped down4 ,for such uses as beams and the sides of tanks where great strength is needed1 the cement is often reinforced1 that is1 rods of iron or steel are embedded in it4 ,for floors1 a sheet of woven wire is often stretched out and embedded4 ,at first only solid blocks1 made to imitate rough stone1 were used for houses1 but the hollow block soon took their place4 ,this is cheaper2 houses built this way are warmer in winter and cooler in summer2 and it prevents moisture from working through the walls4 ,many cities have regulations about the use of hollow blocks1 all the more strict because concrete is comparatively new as a building material4 ,in ,philadelphia the blocks must be composed of at least one barrel of ,portland cement to five barrels of crushed rock or gravel4 ,they must be three weeks old or more before being used2 the lintels and sills of the doors must be reinforced2 and every block must be marked1 so that if the building should not prove to be of proper strength1 the maker may be known4 ,there would seem1 however1 to be little question of the quality of the blocks1 for samples must pass the tests of the ,bureau of ,building ,inspection4 ,even better than the hollow block is the method of making the four walls of a house at once by building double walls of boards and pouring in the concrete4 ,when this has hardened1 the boards are removed1 and whatever sort of finish the owner prefers is given to the walls4 ,they can be treated by spatter-work1 pebble dash1 or in other ways before the cement is fully set1 or by bush hammering and tool work after the cement has hardened4 ,coloring matter can be mixed with the cement in the first place2 and if the owner decides to change the color after the house is completed1 he can paint it with a thin cement of coloring matter mixed with plaster of ,paris4 ,a concrete house has several advantages4 ,in the first place1 it will not burn4 ,neither will granite1 but granite will fall to pieces in a hot fire4 ,granite is made of quartz1 mica1 and feldspar1 as has been said before4 ,these three do not expand alike in heat2 and therefore great flakes of the stone split off1 so that it really seems to melt away4 ,a well-made concrete is not affected by fire4 ,it will not burn1 and it will not carry heat to make other things burn4 ,for a concrete house no paint is needed and less fuel will be required to keep it warm4 ,if the floors are made with even a very little slant1 house-cleaning consists of removing the furniture and turning on the hose4 ,water-tank1 sink1 washtubs1 and bathtubs can be cast in concrete and given a smooth finish4 ,wooden floors can be laid over the concrete1 or a border of wood can be put around each room for tacking down carpets or rugs4 ,a concrete house may be as ornamental as the owner chooses1 for columns and cornices and mouldings can easily be made of concrete2 and if they are cast in sand1 as iron is1 they will have a finish like sandstone4 ,it is somewhat troublesome to lay concrete in very cold weather1 because of the danger of freezing and cracking4 ,sometimes the materials are heated1 and after the concrete is in place1 straw or sand or sawdust is spread over it4 ,these will keep it warm for several hours1 and so give the concrete a chance to set4 ,sometimes a canvas house is built over the work4 ,when a concrete dam was to be built in the ,province of ,quebec and the mercury was #bj deg4 below zero1 the contractors built a canvas house over one portion of the dam and set up iron stoves in it4 ,when this part was completed1 they took down the house and built it up again over another portion of the dam4 ,sometimes salt is used4 ,salt water is heavier than fresh water and will not freeze so easily4 ,therefore salt put into the water used in making the concrete will enable it to endure more cold without freezing2 but not more than one pound of salt to twelve gallons of water should be used4 ,illustration3 ,,building ,a ,,concrete ,,road ,courtesy ,alpha ,portland ,cement ,co4 ,the concrete mixer travels along the prepared roadbed1 and after it follow the workmen with levelers and stamps4 ,concrete objects to being frozen before it is set1 but it is exceedingly accommodating about working under water4 ,it must1 of course1 be carried in some way through the water to its proper place without being washed away1 but this is easily done4 ,sometimes it is let down in great buckets closed at the top1 but with a hinged bottom that will open when the bucket strikes the rock or soil where the material is to be left4 ,sometimes it is poured down through a tube4 ,sometimes it is dropped in sacks made of cloth4 ,this cloth must be coarse1 so that enough of the concrete will ooze through it to unite the bag and its contents with what is below it and make a solid mass4 ,sometimes even paper bags have been successfully used4 ,the concrete1 made rather dry1 is poured into the bags and they are slid down a chute4 ,the paper soon becomes soft and breaks1 and lets the concrete out4 ,sometimes concrete blocks are moulded on land and lowered by a derrick1 while a diver stands ready to see that they go into their proper places4 ,concrete is used for houses1 churches1 factories1 walls1 sidewalks1 steps1 foundations1 sewers1 chimneys1 piers1 cellar bottoms1 cisterns1 tunnels1 and even bridges4 ,in the country1 it is used for silos1 barn floors1 ice houses1 bins for vegetables1 box stalls for horses1 doghouses1 henhouses1 fence posts1 and drinking-troughs4 ,it is of very great value in filling cavities in decaying trees4 ,all the decayed wood must be cut out1 and some long nails driven from within the cavity part-way toward the outside1 so as to help hold the concrete4 ,then it is poured in and allowed to harden4 ,if the cavity is so large that there is danger of the trunk's breaking1 an iron pipe may be set in to strengthen it4 ,if this is encased in concrete1 it will not rust4 ,a horizontal limb with a large cavity may be strengthened by bending a piece of piping and running one part of it into the limb and the other into the trunk1 then filling the whole cavity with concrete4 ,if the bark is trimmed in such a way as to slant in toward the cavity1 it will sometimes grow entirely over it4 ,concrete is also used for stucco work1 that is1 for plastering the outside of buildings4 ,if the building to be stuccoed is of brick or stone1 the only preparation needed is to clean it and wet it2 then put on the plaster between one and two inches thick4 ,a wooden house must first be covered with two thicknesses of roofing-paper1 then by wire lathing4 ,the concrete will squeeze through the lathing and set4 ,stucco work is nothing new1 and if it is well done1 it is lasting4 ,concrete has been used for many purposes besides building1 and the number of purposes increases rapidly4 ,for blackboards1 refrigerator linings1 and railroad ties it has been found available1 and for poles or posts of all sizes it has already proved itself a success4 ,it has even been suggested as an excellent material for boats1 if reinforced2 and minute directions are given by one writer for making a concrete rowboat4 ,to do this1 the wooden boat to be copied is hung up just above the ground1 and clay built around it1 leaving a space between boat and clay as thick as the concrete boat is to be4 ,the wooden boat is covered with paper and greased1 then the concrete is poured into the space between the boat and the clay mould2 and when it hardens and the wooden boat is removed1 there is a boat of stone--or so the directions declare2 but ,i think most people would prefer one of wood4 ,however it may be with rowboats1 concrete is taking an important place in the construction of battleships1 a backing for armor being made of it instead of teakwood4 ,the ,arizona is built in this way4 ,concrete that is carelessly made is very poor stuff1 and dangerous to use1 for it is not at all reliable and may give out at any time2 but concrete that is made of the best materials and properly put together is an exceedingly valuable article4 ,,iv ,,bricks1 ,,their ,,faults ,,and ,,their ,,virtues ,the simplest way to make a brick is to fill a mould with soft clay1 then take it out and let it stiffen1 and then put it in the sun to dry4 ,this is the way in which the adobe bricks of ,central ,america are made4 ,they answer very well in countries where there is little rain2 but one or two heavy downpours would be likely to melt a house built of such material4 ,clay is a kind of earth containing mostly alumina and silica or sand1 that can be mixed with water1 moulded into any shape1 retain that shape after it is dry1 and become hard by being burned4 ,if you want to make a china cup1 you must have a fine sort of clay called kaolin1 which is pure white when it is fired and is not very common2 but if you want to make bricks1 it will not be at all difficult to find a suitable clay bank4 ,and yet the clay1 even for bricks1 must be of the right kind4 ,if it contains too much silica 7sand71 the brick will not mould well2 if too much alumina it will be weak2 if too much iron1 it will lose its shape in burning2 if too much lime1 it will be flesh-colored when it is burned4 ,if you want to find out whether a building-brick is of good quality1 there are some tests that a boy or girl can apply as well as any one4 ,first1 look the brick over and note whether it is straight and true1 and whether the edges and corners are sharp4 ,strike it1 and see whether it gives a clear1 ringing sound4 ,then weigh it and soak it in water for twenty-four hours4 ,weigh it again1 and if it is more than one fifth heavier than it was before soaking1 it is not of the first quality4 ,after the clay has been dug1 it must be tempered1 that is1 mixed with water and about one third or one fourth as much sand as clay1 and left overnight in a soak pit1 a square pit about five feet deep4 ,in the morning the workmen shovel the mass over and feed it into the machines for forming the bricks4 ,the mixing is better done1 however1 in a ring pit4 ,this is a circular pit twenty-five or thirty feet in diameter1 three feet deep1 and lined with boards or brick4 ,a big iron wheel works from the center to the edge and back again for several hours1 through and through the clay4 ,a method even better than this is to put the clay and sand and water into a great trough1 in which there is a long shaft bristling with knives4 ,the shaft revolves1 mixes the clay1 and pushes it along to the end of the trough4 ,this is called pugging1 and the whole thing--trough1 shaft1 and knives--is a pug mill4 ,in the old days bricks were always made by hand4 ,the moulder stood in front of a wet table whereon lay a heap of soft clay4 ,he either wet or sanded his mould to keep it from sticking4 ,meanwhile1 his assistant had cut a piece of clay and rolled it and patted it into the shape of the mould4 ,in making bricks1 there can be no patching2 the mould must be filled at one stroke1 or else there will be folds in the brick4 ,to make a good brick1 the moulder lifts the clay up above his head and throws it into the mould with all his force4 ,then he presses it into the corners with his thumbs1 scrapes off with a strip of wood any extra clay1 or cuts it off with a wire1 smooths the surface of the brick1 puts mould and brick upon a board1 jerks the mould up and proceeds to make another brick4 ,illustration3 ,,in ,a ,,new ,,jersey ,,brick ,,mill ,copyright by ,underwood and ,underwood4 ,this man is moulding a fire-brick to its final shape4 ,no matter how expert a moulder may be1 brick-making by hand is slow work1 and in most places machines are used4 ,in what is called the soft-mud process1 the clay is pushed on by the pug mill to the end of the trough4 ,there stands a mould for six bricks4 ,a plunger forces the clay into it1 the mould is emptied1 and in a single hour five thousand bricks can be made4 ,by what is called the stiff-mud process1 the stiff clay is put into a machine with an opening the size of the end or side of a brick4 ,the machine forces the clay through this opening1 cuts it off at the proper moment2 and so makes bricks by the thousand without either mould or moulder4 ,a third way of making brick is by what is called the dry process4 ,the clay is pulverized and filled into moulds the length and breadth of a brick1 but much deeper1 and with neither top nor bottom4 ,one plunger from above and another from below strike the clay in the mould with much force1 and make the fine1 smooth brick known as pressed brick4 ,all this is done by machinery1 and some machines make six bricks at a time4 ,these dry bricks are fragile before they are burned1 and must be handled with great care4 ,bricks cannot be put into the kiln while they are still wet1 for when a brick is drying1 it is a delicate article4 ,it objects to being too hot or too cold1 and it will not stand showers or drafts4 ,in some way about a pound of water must be dried out of each brick2 but if you try to hurry the drying1 the brick turns sulky1 refuses to have anything more to do with you1 and proceeds to crack4 ,to dry1 bricks are sometimes spread on floors2 or piled up in racks on short pieces of board called pallets2 and sometimes they are put upon little cars and run slowly through heated tunnels4 ,the last is the best way for people who are in a hurry1 for it takes only from twenty-four to thirty-six hours to make the bricks ready to go to the kiln to be burned4 ,in one sort of kiln1 the bricks themselves make the kiln4 ,they are piled up in arches1 but left a little way apart so the hot air can move freely among them4 ,the sides of the structure are covered with burnt brick and mud1 but the top is left open to allow the steam from the hot bricks to escape4 ,the fires are in flues that are left at the bottom4 ,they must burn slowly at first1 but after a while1 some forty to sixty hours1 the heat becomes intense4 ,thus far the bricks have been grayish or cream-colored1 but now1 if there is iron in them1 they turn red2 if there is lime1 they turn yellow2 if a large amount of lime1 they become flesh-colored4 ,besides this sort of kiln1 which is torn down when the bricks are sufficiently burned1 there is also the permanent kiln1 which has fixed side walls and either an open or closed top4 ,then1 too1 there is a continuous kiln4 ,this has a number of chambers1 and the heat from each one passes into the next2 so that bricks in one chamber may be just warming up while in another they are ready to be taken out4 ,when the bricks come out of the kiln1 some of them are good and some are not4 ,those that were on the outside are not burned enough2 those next it are not well baked1 but can be used for the middle of thick walls4 ,the next ones are of good quality2 but those directly over the fires are so hard and brittle that they are of little use except for pavements4 ,paving-bricks1 however1 are not to be despised4 ,they are not as smooth and well finished as pressed brick1 but they are exceedingly useful4 ,they need as much care in making as any others1 and they must be burned in a much hotter fire to make them dense and hard4 ,the tests for paving-bricks are quite different from those for ordinary building-brick4 ,if first-class paving-bricks weighing fifty pounds are soaked in water for twenty hours1 they take up so little water that they will not weigh more than fifty-one or fifty-one and a half pounds when taken out4 ,to find out how hard they are1 the bricks are weighed and shaken about with foundry shot for a number of hours4 ,then they are weighed again to see how much of their material has been rubbed off4 ,a third test is to put one brick on edge into a crushing machine to see how much pressure it will stand4 ,paving-brick is cheaper than granite blocks1 and if it has a good foundation of concrete covered with sand1 it will last about three fourths as long4 ,brick is less noisy than stone and is easier to clean4 ,not so very long ago1 when particularly handsome bricks were needed for the outside of walls and other places where they would be conspicuous1 they were re-pressed2 that is1 they were made by hand or in a soft-mud machine1 and then1 after drying for a while1 were put into a re-pressing machine to give them a smooth finish4 ,these machines are still used1 but they are hardly necessary1 for the dry-clay brick machine will turn out a smooth brick in one operation4 ,another substance which is made of almost the same materials as brick is terra cotta4 ,to make this1 fire brick1 bits of pottery1 partly burned clay1 and fine white sand are ground to a powder and mixed very thoroughly4 ,this mixture is moulded1 dried1 and burned4 ,until recently1 all terra cotta was of the color that is called by that name1 but now it is made in gray1 white1 and bronze as well4 ,bricks are laid in mortar1 and this makes a wall one solid mass and stronger than it could be without any cement4 ,but mortar does more than this4 ,it is more elastic than brick1 and therefore1 when a wall settles1 the mortar yields a little1 and this often prevents the bricks from cracking4 ,bricks are always thirsty1 and if one is laid in mortar1 it will suck the moisture out of it almost as a sponge will suck up water4 ,the mortar thus has no chance to set1 and so is not strong as it should be4 ,that is why the bricklayer wets his bricks1 especially in summer1 before he puts them in place4 ,lime or cement mortar will not set in freezing weather1 and a brick building put up in the winter is in danger of tumbling down when the warm days of spring arrive4 ,this thirstiness of bricks is their greatest fault4 ,three or four days of driving rain will sometimes wet through a brick wall two feet thick1 crumbling the plaster and spoiling the wallpaper4 ,that is why it is a poor plan to plaster directly on the brick wall of a house4 ,furring strips1 as they are called1 or narrow strips of wood1 should be fastened on first and the laths nailed to these1 or the wall can be painted or oiled on the outside4 ,the best way1 however1 though more expensive1 is to build the wall double4 ,then there is air between the two thicknesses of brick4 ,air is a poor conductor of heat2 so in summer it keeps the heat out1 and in winter it keeps it in4 ,but brick will suck up water from the ground as well as from a storm2 and therefore1 when a brick house is to be built in a wet place1 there ought to be a three-eighths-inch layer of something waterproof1 like asphalt and coal tar1 put on top of one of the layers of brickwork to prevent the moisture from creeping up4 ,bricks have their faults1 but they will not burn1 and when properly used1 they make a most comfortable and enduring house4 ,v ,,at ,,the ,,gold ,,diggings ,when gold was first discovered in ,california1 in #ahdh1 people from all over the world made a frantic rush to get there1 every one of them hoping that he would be lucky enough to make his fortune1 and fearing lest the precious metal should be gone before he could even begin to dig4 ,the gold that these men gathered came from what were called placers2 that is1 masses of gravel and sand along the beds of mountain streams4 ,each miner had a pan of tin or iron1 which he filled half-full of the gravel1 or pay dirt1 as the miners called it4 ,then1 holding it under water1 he shook off the stones and mud over the side of the pan1 leaving grains of gold mixed with black sand at the bottom4 ,this black sand was iron1 and after a while the miners removed it with a magnet1 dried what remained1 and blew away the dust1 leaving only the grains of gold4 ,another contrivance which soon came into use was the cradle4 ,this was a long box1 sometimes only a hollowed-out log4 ,at the top was a sieve which sifted out the stones4 ,nailed to the bottom of the cradle were small cleats of wood1 or riffles1 which kept the water from running so fast as to sweep the gold out of the cradle with it4 ,the cradle was placed on rockers and was also tilted slightly4 ,the miner shoveled the gravel into the top of the cradle and his partner rocked it4 ,the sieve kept back the stones1 the water broke up the lumps of earth and gravel and washed them down the cradle1 and the grains of gold were stopped by the riffles1 and sank to the bottom4 ,sometimes the pay dirt continued under a stream4 ,to get at it1 the miners often built a little canal and turned the water into a new channel2 then they could work on the former bed of the river4 ,before many years had passed1 the gold that was near the surface had been gathered4 ,the miners then followed the streams up into the mountains1 and found that much of the gold had come from beds where in ancient times rivers had flowed4 ,there was gold still remaining in these beds1 but it was poorly distributed1 the miners thought4 ,sometimes there would be quite an amount in one place1 and then the miner would dig for days without finding any more4 ,even worse than this was the fact that these gravel beds were not on the top of the ground1 but were covered up with soil and trees4 ,evidently the slow work with pans and cradles would not pay here2 but it occurred to some one that if a powerful stream of water could be directed against the great banks of earth1 as water is directed against a burning building1 they would crumble1 the dirt could be washed down sluices1 and the gold be saved4 ,this was done4 ,great reservoirs were built high up in the mountains1 and water was brought by means of ditches or pipes to a convenient place4 ,then it was allowed to rush furiously through a hose and nozzle1 and the great stream coming with tremendous force was played upon the banks of gravel4 ,the banks crumbled1 the gravel was washed into a string of sluices1 or long boxes with riffles to catch the gold4 ,soon the miners found that if quicksilver was put into these sluices1 it would unite with the gold and make a sort of paste called amalgam4 ,then if this amalgam was heated1 the quicksilver would be driven off in the form of gas1 and the gold would remain in a beautiful yellow mass4 ,illustration3 ,,hydraulic ,,gold ,,mining ,a placer mine at ,gold ,point1 ,california1 where tremendous streams of water under high pressure are busy washing away the side of a gold-bearing hill4 ,the ancient rivers had also carried gold to the valleys1 and to collect this a dredge1 which the miners called a gold ship1 came into use4 ,the ship part of this machine is an immense flat scow4 ,stretching out from one end is something which looks like a moving ladder4 ,this is the support of an endless chain of buckets1 each of which can bite into the gravel and take a mouthful of five or six hundred pounds4 ,they drop this gravel into a big drum which is continually revolving4 ,water flows through the drum1 and washes out the sand and bits of gold over large tables1 where by means of riffles and quicksilver the gold is captured4 ,this scow was usually on dry land at first2 but its digging soon made a lake1 and then it floated4 ,it must be more fascinating to hold a pan in your own hands and pick out little grains of gold or perhaps even a big piece of it with your own fingers1 but if the gravel is good the dredge makes more money4 ,in ,alaska the great difficulty in mining is that1 except at the surface1 the ground is frozen all the year round4 ,at first1 the miners used to thaw the place where they wished to dig by building wood fires2 but this was a slow method1 and now the thawing is done by steam4 ,they carry the steam in a pipe to the place where the digging is to be done1 and send it through a hose4 ,at the end of the hose is a pointed steel tube4 ,they hammer this tube into the ground and let some steam pass through the nozzle4 ,this softens the ground so that picks and shovels may be used4 ,there is generally cold enough in ,alaska1 but once at least the miners had to manufacture it4 ,the gold-bearing gravel was deep1 the ground was flat1 and it was often overflowed4 ,they set up a freezing plant1 and shut in their land with a bulkhead of ice several feet thick4 ,then they pumped out what water was already in and did their work with no more trouble4 ,when gold began to grow less in the ,california gravel1 the miners looked for it in the rocks on the mountain-side4 ,the placer miners laughed at them and called their shafts coyote holes2 but in time the placers failed1 while nearly all of our gold to-day comes from veins of white quartz in the rocks4 ,a vein of gold is the most capricious thing in the world4 ,it may be so tiny that it can hardly be seen1 then widen and grow rich in gold1 then suddenly come to an end4 ,this is why a new mine is so uncertain an enterprise4 ,the gold may hold out and bring fortunes to the investors1 or it may fail1 and then all they will have to show for their money is the memory that they put it into a hole in the ground4 ,the managers of a few of the well-established mines1 however1 have explored so far as to make sure that there is gold enough for many years of digging4 ,the mining engineer must be a very wide-awake man4 ,it is not enough for him simply to remember what was taught him in the schools of mining2 he must be bright enough to invent new ways of meeting difficulties4 ,no two mines are alike1 and he must be ready for all sorts of emergencies4 ,a gold mine now consists of a shaft or pit dug several hundred feet down into the rock1 with levels or galleries running off from it and with big openings like rooms made where the rock was dug out4 ,the roofs of the rooms are supported by great timbers4 ,to break away the rock1 the miner makes a hole with a rock drill worked by electricity or compressed air1 puts powder or dynamite into the hole and explodes it4 ,the broken rock is then raised to the surface and crushed in a stamping mill4 ,here the ore is fed into a great steel box called a mortar4 ,five immense hammers1 often weighing a thousand pounds apiece1 drop down upon the ore1 one after another1 until it is fine enough to go through a wire screen in the front of the box4 ,when two hundred or more of these hammers are pounding away with all their might1 a stamping mill is a pretty noisy place4 ,the ore1 crushed to a fine mud1 now runs over sloping tables covered with copper4 ,sticking to the top of the copper is a film of quicksilver4 ,this holds fast whatever gold there may be and makes an amalgam1 which is scraped off from time to time1 and the quicksilver is driven from the gold by heat4 ,gold that is not united with other metals is called free milling gold4 ,much of it1 however1 is found in combination with one metal or another1 and is known as rebellious or refractory gold4 ,such gold may sometimes be set free by heat1 and sometimes by chemicals4 ,one way is by the use of chlorine gas1 and the story of it sounds almost like ,the house that ,jack built4 ,it might run somewhat like this3 ,this is the salt that furnishes the chlorine4 ,this is the chlorine gas that unites with the gold4 ,this is the chloride that is formed when the chlorine gas unites with the gold4 ,this is the water that washes from the tank the chloride that is formed when the chlorine gas unites with the gold4 ,this is the sulphate of iron that unites with the chlorine gas of the chloride that the water washes from the tank that is formed when the chlorine gas unites with the gold--and leaves the gold free4 ,another method is by the use of cyanide4 ,more than a century ago a chemist discovered that if gold was put into water containing a little cyanide1 the gold would dissolve1 while quartz and any metals that might be united with the gold would settle in the tank4 ,the water in which the gold is dissolved is now run into boxes full of shavings of zinc and is precipitated upon them2 that is1 the tiny particles of gold in the water fall upon the zinc and cling to it4 ,zinc melts more easily than gold1 so if this gilded zinc is put into a furnace1 the zinc melts and the gold is set free4 ,very often gold is found combined with lead or copper4 ,it must then be melted or smelted in great furnaces4 ,the metal is heavier than the rock and settles to the bottom of the furnace4 ,it is then drawn off and the gold is separated from the other metals1 usually by electricity4 ,sometimes large pieces of gold called nuggets are found by miners4 ,the largest one known was found in ,australia4 ,it weighed #aij pounds and was worth #db1jjj4 ,sometimes spongy lumps of gold are found2 but as a general thing gold comes from the little specks scattered through veins in rock1 and much work has to be done before it can be made into coins or jewelry4 ,it is too soft for such uses unless some alloy1 usually copper or silver1 is mixed with it to make it harder4 ,sometimes it is desirable to know how much alloy has been added4 ,the jeweler then makes a line with the article on a peculiar kind of black stone called a touchstone1 and by the color of the golden mark he can tell fairly well how nearly pure the article is4 ,to be more accurate1 he pours nitric acid upon the mark4 ,this eats away the alloy and leaves only the gold4 ,gold is a wonderful metal4 ,it is of beautiful color2 it can be hammered so thin that the light will shine through it2 few acids affect it1 and the oxygen which eats away iron does not harm it4 ,pure gold is spoken of as being twenty-four carats fine1 from carat1 an old weight equal to one twenty-fourth of an ounce troy4 ,watchcases are from eight to eighteen carats fine2 chains are seldom more than fourteen2 and the gold coins of the ,united ,states are about eleven parts of gold and one of copper4 ,coins wear in passing from one person to another1 and that is why the edges are milled1 so that it may be more easily seen when they have become too light to be used as coins4 ,when such pieces come into the hands of the ,government1 they must be recoined4 ,,vi ,,the ,,story ,,of ,a ,,silver ,,mine ,a man who goes out in search of a mine is called a prospector4 ,the best prospector is a man who has learned to keep his eyes open and to recognize the signs of gold and silver and other metals4 ,a faithful friend goes with him1 a donkey or mule which carries his bacon and beans1 blankets1 saucepan1 and a few tools1 such as a pan1 pick1 shovel1 hammer1 and axe4 ,sometimes the prospector also takes with him a magnifying glass and a little acid to test specimens1 but usually he trusts to his eyes alone4 ,when these few things have been brought together1 the prospector and the donkey set out4 ,they wander over the hills and down into the canyons4 ,if a rock is stained red1 the prospector examines it to see whether it contains iron2 if it is green1 he looks for copper4 ,in the canyons and along the creeks he often tests the gravel for traces of some valuable metal4 ,if he finds any of these traces along the stream1 he follows them on the bank until they stop2 then he carefully examines the bank of the stream or the nearest hillside4 ,if he continues to find bits of metal1 they will lead him to a vein of ore1 from which they have been broken by the wind1 rain1 and frost4 ,generally a prospector is looking for some one special metal1 and in his search he often overlooks some other metal2 for instance1 thousands of the gold-seekers who rushed to ,california in #ahdi hurried through ,nevada on their way4 ,if they had only known what was under their feet1 they would have taken their picks and shovels and begun to dig1 instead of trying to get out of the region as soon as might be4 ,ten years later1 the ,california placers were becoming exhausted1 and miners began to go elsewhere in their search for gold4 ,among those who were working in what is now the ,state of ,nevada were two ,irishmen who had been unlucky in ,california and had fared no better in ,nevada4 ,they wanted to go somewhere else1 but they had not money enough for the journey2 so they kept on with their work at the foot of ,mount ,davidson1 washing the gravel and saving the little gold that they found4 ,they were annoyed by some heavy black stuff that united with the quicksilver in their cradles1 interfered with the saving of the gold1 and put them in a very bad temper4 ,at length a man named ,henry ,comstock came along1 who told them that this black stuff was silver ore4 ,they examined the mountain-side1 and discovered the outcrop or edge of a great vein containing gold and also silver4 ,it is no wonder that people rushed from the east and west to the wonderful new mines1 for it was plain that these new diggings were not mere placers1 but rich veins that many years of working might not exhaust4 ,every newcomer hoped to discover a vein2 and within a year or two the district around the ,comstock lode was full of deep shafts1 many of them abandoned and half-hidden by low brush1 but some of them yielding quantities of gold and silver4 ,before this1 there had been only about a thousand people in what is now ,nevada1 but in two years after the discovery of silver1 there were #af1jjj1 and a new ,territory was formed4 ,the miners knew how to get gold out of ore1 but silver was another matter1 and some of it was difficult to extract4 ,they had so much trouble that they were ready to believe in any treatment of the ore1 no matter how absurd1 that promised to help them out of their difficulties4 ,some of them were actually persuaded that the juice of the wild sagebrush would bring the silver out4 ,it is no wonder that they were troubled1 for in the ,comstock lode were not only gold and silver1 but ten or twelve other metals or combinations of silver with something else4 ,at length processes were invented for treating the different kinds of ore4 ,some kinds were crushed in a stamping mill1 then ground to a powder and mixed with quicksilver or mercury4 ,this mercury united with both the gold and the silver1 making an amalgam4 ,the amalgam1 together with the finely ground ore1 was put into a settler1 and here the heavy amalgam sank to the bottom and was then strained4 ,the extra mercury was collected1 and the amalgam was put into a retort or kettle and heated4 ,the mercury became a gas and was driven off from the gold and silver1 then caught in a vessel cool enough to condense it1 just as a cold plate held in steam will collect drops of water4 ,sometimes the ore was mixed with copper and lead4 ,in that case common salt and copper sulphate were used4 ,some ore had to be roasted in a furnace in order to drive off the sulphur4 ,illustration3 ,,the ,,story ,,of ,a ,,spoon ,courtesy ,the ,gorham ,co4 7#a7 ,silver strip blanked4 7#b7 ,pinched4 7#c7 ,graded4 7#d7 ,outlining of ,handle4 7#e7 ,stamped ,handle4 7#f7 ,spoon completely trimmed4 7#g1 #h7 ,finished spoons4 ,there were great and unusual dangers to be met in getting the ore4 ,the vein of quartz which bore it was fifty or sixty feet wide4 ,some was hard1 and some so soft and crumbling that pillars would not hold up the roof4 ,the passageways were then lined with heavy logs standing on either side1 other logs laid across their tops1 and all bolted firmly together4 ,nevertheless1 they twisted and fell1 and slowly but certainly the whole mass of earth and rock1 two hundred or more feet in thickness1 was coming down upon the heads of the miners4 ,the work on the ,comstock mines had come to an end unless a man could be found able to invent some system of support not laid down in the books4 ,the man was found4 ,he took short1 square timbers five or six feet long1 put them together as if they were the sides and ends of square boxes1 and piled them one above another1 making hollow pillars4 ,he fastened these firmly together and filled the space inside with waste rock1 thus making strong1 solid pillars that would support almost any weight that could be put upon them4 ,there were two other dangers1 water and heat4 ,the vein was porous and water was constantly trickling out of it4 ,then1 too1 there were water pockets1 or natural reservoirs in the rock1 and any moment the stroke of a pick might let out a torrent and force the miners to run for their lives4 ,sometimes minerals were dissolved in this water1 and the men with closed eyes and swollen faces had to be hurried to the surface for treatment4 ,powerful pumps had to be used and the water sent away through long lines of pipes4 ,this water was warm1 and in very deep workings in the ,comstock vein it was boiling hot4 ,even with quantities of ice sent down to cool them1 the men could work in some places only a short time4 ,in ,san ,francisco there was a mining engineer named ,adolph ,sutro who planned to remedy these troubles by driving a big four-mile tunnel through the heart of the mountain1 letting out the hot water and the foul air4 ,the owners of some of the mines joined him in raising the money1 and the tunnel was dug4 ,through this the water ran out4 ,the mines were freed of foul air and fresh air was driven in4 ,the ,comstock lode has given up an amazing amount of precious metal4 ,between #ahfj and #ahij it produced #cdj1jjj1jjj4 ,after #ahij1 however1 its product grew less4 ,the vein was not so rich1 the price of silver fell1 while the cost of mining it at great depths increased4 ,not nearly so much was mined1 and at length water rose in the mines up to the level of the ,sutro ,tunnel4 ,in #aijj new machinery was put in and new methods were adopted1 such as treating the tailings with cyanide and so saving much of the precious metal from them4 ,from the beginning the ,comstock mines have been so ready to follow improved methods that they have been called the mining school of the world4 ,great quantities of silver are used for making jewelry and for tableware4 ,the one objection to its use is that silver likes to unite with sulphur1 and thus the silver easily becomes black4 ,there is sulphur in the yolk of an egg and that is why the spoon with which it has been eaten turns black4 ,even if silverware is not used1 it tarnishes1 especially in towns1 because there is so much sulphureted hydrogen in the air4 ,in perfectly pure air1 it would not tarnish4 ,silver is harder than gold1 but not hard enough to be used without some alloy1 usually copper4 ,tableware is solid even if it contains alloy enough to stiffen it4 ,it is plated if it is made of some cheaper metal and covered with silver4 ,the old way of doing this was to fasten with bits of solder a thin sheet of silver to the cup or vase or whatever was in hand and heat it4 ,this did fairly well for large1 smooth articles2 but it was almost impossible to finish the edges of spoons so as not to show the two metals4 ,if you look at a plated spoon to-day1 however1 you will find that there is no break at the edge1 and so far as you can tell by the eye1 it is solid silver4 ,if you look on the back of the spoon1 you will perhaps see ,rogers ,bros4 #ahdf4 ,these men were the first silvermakers in this country to plate tableware by electricity4 ,to make a spoon1 they formed one out of iron or copper and made sure that it was perfectly clean4 ,then across a bath of silver cyanide1 potassium cyanide1 and water they laid two metal rods1 and from these they hung a spoon at one end and a plate of silver at the other4 ,these rods were connected with the two poles of a battery4 ,the electrical current passed through them1 released the silver from the silver cyanide1 and this was deposited upon the spoon4 ,the cyanide that had lost its silver took enough more from the silver plate to make up4 ,the amount of silver on the spoon depends upon the length of time it remains in the bath4 ,it is weighed before plating and again afterwards1 to make sure that the proper amount of silver has been deposited upon it4 ,on the back of many plated articles you will see the words ,triple plate or ,quadruple plate4 ,if the article has been made by a reliable firm1 this means that the triple plate it manufactures contains three times as much silver as single plate1 and that quadruple plate contains four times as much4 ,a piece of silver looks just as well if it has stayed in the bath only a few minutes1 but of course it has taken on so little silver that this will soon wear off and show the cheaper metal4 ,a large amount of silver is used for coins4 ,when the ,united ,states needs dollars1 half-dollars1 quarters1 and dimes1 notice is given and offers are called for1 stating the quantity for sale and its price4 ,when it is delivered1 it is first of all assayed2 that is1 tested to find out how nearly pure it is and how much it is worth4 ,next it is refined1 or purified from other metals1 mixed with a little copper to harden it1 then melted again and poured into moulds to make bars4 ,if dollars are to be made1 the bar is made thinner by passing it between heavy rollers1 and blanks for dollars are cut out with a die4 ,these blanks are weighed and every one that is too heavy or too light is put back to be melted over again4 ,thus far these dollars are only round1 smooth pieces of metal4 ,they must be milled to give them a rough edge1 and they must be stamped4 ,for stamping1 the piece of metal is placed between two dies1 one above and one below1 and these close upon it with a force of one hundred and fifty tons4 ,every part of the process of manufacturing money is carried on with the utmost care4 ,the places where coins are made are called mints4 ,the ,united ,states has four2 the oldest is in ,philadelphia1 and there are branch mints in ,san ,francisco1 ,new ,orleans1 and ,denver4 ,coins minted in ,philadelphia have no distinguishing mark2 but coins minted in ,san ,francisco are marked with a tiny ,s2 if minted in ,new ,orleans1 with an ,o2 and if in ,denver1 with a ,d4 ,,vii ,,iron1 ,,the ,,everyday ,,metal ,did you ever realize that your food and clothes1 your books1 and the house in which you live all depend upon iron8 ,vegetables1 grains1 and fruits are cultivated with iron tools2 fish are caught with iron hooks1 and many iron articles are used in the care and sale of meat4 ,clothes are woven on iron looms1 sewed with iron needles1 and fastened together with buttons containing iron4 ,books are printed and bound by iron machines1 and sometimes written with iron pens or on iron typewriters4 ,houses are put together with nails2 and indeed1 there is hardly an article in use that could be made as well or as easily if iron was not plenty4 ,if you were making a world and wanted to give the people the most useful metal possible1 the gift would have to be iron2 and the wisest thing you could do would be to put it everywhere1 but in such forms that the people would have to use their brains to make it of service4 ,this is just the way with the iron in our world4 ,wherever you see a bank of red sand or red clay or a little brook which leaves a red mark on the ground as it flows1 there is iron4 ,iron is in most soils1 in red bricks1 in garnets1 in ripening apples1 and even in your own blood4 ,it forms one twentieth part of the crust of the earth4 ,iron dissolves in water if you give it time enough4 ,if you leave a steel tool out of doors on a wet night1 it will rust2 that is1 some of the iron will unite with the oxygen of the water4 ,this is rather inconvenient1 and yet in another way this dissolving is a great benefit4 ,through the millions of years that are past1 the oxygen of the rain has dissolved the iron in the hills and has worked it down1 so that now it is in great beds of ore or in rich pockets that are often of generous size4 ,one of them1 which is now being mined in ,minnesota1 is more than two miles long1 half a mile wide1 and of great thickness4 ,the rains are still at work washing down iron from the hills4 ,they carry the tiny particles along as easily as possible until they come upon limestone4 ,then1 almost as if it was frightened1 the brook drops its iron and runs away as fast as it can4 ,sometimes it flows into a pond or bog in which are certain minute plants or animals that act as limestone does1 and the particles of iron fall to the bottom of the pond4 ,in colonial days much of the iron worked in ,america was taken from these deposits4 ,one kind of iron is of special interest because it comes directly from the sky1 and falls in the shape of stones called meteorites1 some of which weigh many tons4 ,in some of the old fables about wonderful heroes1 the stories sometimes declare that the swords with which they accomplished their deeds of prowess fell straight from the heavens1 which probably means that they were made of meteoric iron4 ,fortunately for the people and their homes1 meteorites are not common1 but every large museum has specimens of them4 ,it is not especially difficult to make iron if you have the ore1 a charcoal fire in a little oven of stones1 and a pair of bellows4 ,put on layers of charcoal alternating with layers of ore1 blow the bellows1 and by and by you will have a lump of iron4 ,it is not really melted1 but it can be pounded and worked4 ,this is called the ,catalan method1 because the people of ,catalonia in ,spain made iron in this way4 ,it is still used by the natives of the interior of ,africa4 ,but if all the iron was made by this method1 it would be far more costly than gold4 ,the man who makes iron in these days must have an immense blast furnace1 perhaps one hundred feet high1 a real pillar of fire4 ,into this furnace are dropped masses of ore1 and with it coke to make it hotter and limestone to carry off the silica slag1 or worthless part4 ,to increase the heat1 blasts of hot air are blown into the bottom of the furnace4 ,this air is heated by passing it through great steel cylinders as high as the furnace4 ,the fuel used is nothing more than the gases which come out at the top of the furnace4 ,the slag is so much lighter than iron that when the ore is melted the slag floats on top just as oil floats on water1 and can be drained out of the furnace through a higher opening than that through which the iron flows4 ,the slag tap is open most of the time1 but the iron tap is opened only once in about six hours4 ,it is a magnificent sight when a furnace is tapped and the stream of iron drawn off4 ,imagine a great shed1 dark and gloomy1 with many workmen hurrying about to make ready for what is to come4 ,the floor is of sand and slopes down from the furnace4 ,through the center of this floor runs a long ditch straight from the furnace to the end of the shed4 ,opening from it on both sides are many smaller ditches2 and connecting with these are little gravelike depressions two or three feet long and as close together as can be4 ,these are called pigs4 ,when the time has come1 the workmen gather about the furnace1 and with a long bar they drill into the hard-baked clay of the tapping hole4 ,suddenly it breaks1 and with a rush and a roar the crimson flood of molten iron gushes out4 ,it flows down the trench into the ditches1 then into the pigs1 till their whole pattern is marked out in glowing iron4 ,now the blast begins to drive great beautiful sparks through the tapping hole4 ,this means that the molten iron is exhausted4 ,the blast is turned off1 and the mud-gun is brought into position and shoots balls of clay into the tapping hole to close it for another melting1 or drive4 ,the crimson pigs become rose-red1 darken1 and turn gray4 ,the men play streams of water over them and the building is filled with vapor4 ,as soon as the pigs are cool enough1 they are carted away and piled up outside the building4 ,in some iron works moulds of pressed steel carried on an endless chain are used instead of sand floors4 ,the chain carries them past the mouth of a trough full of melted iron4 ,they are filled1 borne under water to be cooled1 and then dropped upon cars4 ,a first-class machine can make twenty pigs a minute4 ,illustration3 ,,in ,,the ,,steel ,,foundry ,it is a dangerous business to visit a steel mill4 ,tremendous kettles travel overhead on huge cranes1 hot metal flows from unexpected places1 and there is a constant glow and steam and roar everywhere to confuse the unwary4 ,most of the iron made in blast furnaces is turned into steel4 ,steel has been made for centuries1 but until a few years ago the process was slow and costly4 ,a workman's steel tools were treasures1 and a good jackknife was a valuable article4 ,railroads were using iron rails4 ,they soon wore out1 but at the suggestion to use steel1 the presidents of the roads would have exclaimed1 ,steel1 indeed6 ,we might as well use silver6 ,trains needed to be longer and heavier1 but iron rails and bridges could not stand the strain4 ,land in cities was becoming more valuable2 higher buildings were needed1 but stone was too expensive4 ,everywhere there was a call for a metal that should be strong and cheap4 ,iron was plentiful1 but steel was dear4 ,a cheaper method of making iron into steel was needed2 and whenever there is pressing need of an invention1 it is almost sure to come4 ,before long1 what is known as the ,bessemer process was invented4 ,one great difficulty in the manufacture of steel was to leave just the right amount of carbon in the iron4 ,bessemer simply took it all out1 and then put back exactly what was needed4 ,molten iron1 tons and tons of it1 is run into an immense pear-shaped vessel called a converter4 ,fierce blasts of air are forced in from below4 ,these unite with the carbon and destroy it4 ,there is a roar1 a clatter1 and a clang4 ,terrible flames of glowing red shoot up4 ,suddenly they change from red to yellow1 then to white2 and this is the signal that the carbon has been burned out4 ,the enormously heavy converter is so perfectly poised that a child can move it4 ,the workmen now tilt it and drop in whatever carbon is needed4 ,the molten steel is poured into square moulds1 forming masses called blooms1 and is carried away4 ,more iron is put into the converter1 and the work begins again4 ,the ,bessemer process makes enormous masses of steel and makes it very cheaply2 but it has one fault--it is too quick4 ,the converter roars away for a few minutes1 till the carbon and other impurities are burned out2 and the men have no control over the operation4 ,in what is called the open-hearth process1 pig iron1 scrap iron1 and ore are melted together with whatever other substances may be needed to make the particular kind of steel desired4 ,this process takes much longer than the ,bessemer1 but it can be controlled4 ,open-hearth steel is more homogeneous1--that is1 more nearly alike all the way through1--and is better for some purposes1 while for others the ,bessemer is preferred4 ,steel is hard and strong1 but it has two faults4 ,a steel bar will stand a very heavy blow and not break1 but if it is struck gently many thousand times1 it sometimes crystallizes and may snap4 ,a steel rail may carry a train for years and then may crystallize and break and cause a wreck4 ,inventors are at work discovering alloys to prevent this crystallization4 ,the second fault of steel is that it rusts and loses its strength4 ,that is why an iron bridge or fence must be kept painted to protect it from the moisture in the air4 ,if all the iron that is in use should suddenly disappear1 did you ever think what would happen8 ,houses1 churches1 skyscrapers1 and bridges would fall to the ground4 ,railroad trains1 automobiles1 and carriages would become heaps of rubbish4 ,ships would fall apart and become only scattered planks floating on the surface of the water4 ,clocks and watches would become empty cases4 ,there would be no machines for manufacturing or for agriculture1 not even a spade to dig a garden4 ,everybody would be out of work4 ,if you wish to see how it would seem1 try for an hour to use nothing that is of iron or has been made by using iron4 ,,viii ,,our ,,good ,,friend ,,copper ,where did rocks come from8 ,some were deposited in water1 like limestone and like the shale and sandstone that lie over the strata of coal4 ,others were made by fire1 and were thrown up in a melted state from the interior of the earth4 ,such rocks are the ,giant's ,causeway in ,ireland and the ,palisades of the ,hudson ,river4 ,they are called igneous rocks1 from the ,latin word ignis meaning fire4 ,when the igneous rocks were thrown up to the surface of the earth1 they brought various metals with them4 ,how the metals happened to be there ready to be brought up1 no one knows4 ,some people think they were dissolved in water and then deposited2 others think that electricity had something to do with their formation4 ,however that may be1 metals were brought up with the igneous rocks1 and one of these metals is copper4 ,now1 to one who did not know how to work iron1 copper was indeed a wonderful treasure1 for it made very good knives and spoons4 ,the people who lived in this country long before the ,indians came understood how to use it1 and after a while the ,indians themselves found out its value4 ,they did not trouble themselves to dig for it2 they simply picked it up from the ground1 good pure metal in lumps2 and with stones for hammers they beat it into knives4 ,there was only one place in what is now the ,united ,states where they could do this1 and that was in northern ,michigan4 ,a long point of land stretches out into ,lake ,superior as if it was trying to see what could be found there4 ,just beyond its reach is ,isle ,royal2 and in these two places there was plenty of copper1 enough for the ,indians1 enough for the people who have come after them1 and enough for a great many more4 ,one piece of copper which the ,indians did not pick up1 and the ,united ,states ,government did1 is the famous ,ontonagon ,boulder1 so called because it was found near the ,ontonagon ,river4 ,it weighs more than three tons4 ,the ,indians would have been glad to make use of it1 but it was too hard for their tools1 and so they are said to have worshiped it as a god4 ,it is now in the ,national ,museum in ,washington4 ,the lumps of copper1 such as those which delighted the hearts of the ,indians1 are known to-day as barrel copper1 because they are of a good size to be dropped into barrels and carried away for smelting4 ,the great boulders which the ,indians could not use are called mass copper4 ,sometimes they weigh as much as five hundred tons4 ,the copper in them is almost pure1 and a big boulder is worth perhaps #bjj1jjj4 ,nevertheless1 the mine-owners do not rejoice when they come upon such a mass in their digging1 for it cannot be either dug or blasted1 and has to be cut away with chisels of chilled steel4 ,now1 a mine may be wonderfully rich in metal1 but if working it costs too much1 then another mine with less metal but more easily worked will pay better4 ,so it is with these great masses of copper4 ,they are interesting to study and they look well in museums1 but they do not pay so well as the stamp copper which is found in humble little bits in the gangue1 or the rock of the vein1 and has to be pounded in a stamp mill4 ,this gangue is dug out and broken up as in mines of other metals4 ,the copper is much heavier than the rock1 so it is easy to get rid of the worthless gangue by means of a flow of water4 ,the gangue of the ,michigan mines is exceedingly hard1 but the stamps are so powerful that one can crush five hundred tons in less than twenty-four hours4 ,some copper can be taken out of the mortars at once1 but the rest of the broken gangue is fed to jigs1 or screens1 which are kept under jets of water4 ,the water is thrown up from below and the lighter rock is tossed away1 while the heavier copper falls through the tiny holes in the screens4 ,illustration3 ,,in ,a ,,copper ,,smelter ,the men are pouring hot copper into moulds for castings4 ,after the ore has been through all these experiences1 it comes out looking like dark-colored sand or coarse brown sugar4 ,it is not interesting1 and no one who saw it for the first time would ever fancy that it was going to turn into something beautiful4 ,it is dumped into freight cars and trundled off to the smelting furnaces4 ,but however uninteresting it looks1 it is well worth while to follow these cars to see what happens to it at the smelters4 ,first of all1 even before it goes into the smelting furnace1 it must be roasted4 ,there is usually sulphur combined with the copper1 and roasting will get rid of much of it4 ,in some places this is done by building up a great heap of ore with a little wood4 ,the wood is kindled1 and by the time it has burned out1 the sulphur in the ore has begun to burn1 and in a good-sized heap it will continue to burn for perhaps two months4 ,such a heap is a good thing to keep away from1 for the fumes of sulphur are very disagreeable4 ,indeed1 they will kill trees and other growing things wherever the wind may carry them1 even several miles away4 ,the managers of mines of copper as well as of gold and silver have learned to economize2 and it has been found that instead of letting these fumes go into the air1 they may be made to pass through acid chambers lined with zinc and full of water4 ,the water holds the fumes1 and can be used in making sulphuric acid4 ,after the ore has been roasted1 it is put into the furnace for smelting4 ,if you should make an oven and put into it a mixture of wood and roasted copper1 that would be a smelting furnace4 ,set the wood on fire1 pump in air to make the flame hot1 and if your furnace could be made hot enough1--that is1 #bcjj deg4 ,f41 or about eleven times as hot as boiling water1--you could smelt copper4 ,of course the furnace of a real smelting factory will hold tons and tons of copper ore and has all sorts of improvements1 but after all it is in principle only an oven with wood and ore and draft4 ,another sort of furnace1 which is better for some kinds of ore1 has a grate for the fire and a bed above it for the copper4 ,imagine an enormous furnace holding between two and three hundred tons of metal and burning with such a terrific heat that by contrast boiling water would seem cool and comfortable4 ,suddenly1 while you stand looking at it1 but a long way off1 a door flies open and the most beautiful cascade--only it is not a waterfall1 but a copper fall--pours out4 ,it looks like red1 red gold1 rich and wonderful1 with little flames of red and blue dancing over it4 ,it might almost be one of the fire-breathing dragons of the old story-books2 and if it should get loose1 it would devour whomever it touched far quicker than any dragon4 ,it hardly seems as if any one could manage such a monster2 but it looks easy1 after you have seen it done4 ,an enormous horizontal wheel revolves slowly4 ,on its edge are moulds shaped like bricks1 but much larger4 ,on the hub of the wheel a workman sits to direct the filling of these4 ,a set of them is filled1 and moves on1 and others take their place4 ,when they are partly cooled1 another workman1 at the farther side of the wheel1 pries them out of the mould and drops them into water4 ,then by the aid of the fingers of a machine and those of men1 they are loaded upon cars4 ,in copper there is often some gold and silver4 ,the precious metals do not make the copper any better1 and if they can be separated from it1 they are well worth the trouble4 ,this is done by electricity4 ,it is so successful that the metallurgists are hoping soon to take a long step ahead and by means of electricity to produce refined copper directly from the ore4 ,indeed1 this has been done already in the laboratories1 but before the managers of mines can employ the method1 a way of making it less expensive must be discovered4 ,no mine that wastes anything is as well managed as it might be2 and superintendents are constantly on the watch for cheaper methods and for ways to make the refuse matter of use4 ,even the scoria1 or slag from the furnaces1 has been found to be good for something1 and now it is made into a coarse sort of brick that for certain rough uses is of value4 ,by the way1 the shaft of a copper mine1 the ,red ,jacket1 has shown itself of use in a manner that no one expected1 namely1 it helps to prove that the earth turns around4 ,this shaft is the deepest mining shaft in the world1 and when you get into the cage1 you go down a full mile toward the center of the earth4 ,if you drop any article into the shaft1 it always strikes the east side before reaching the bottom4 ,the only way to explain this is that the earth turns toward the east4 ,copper mixed with zinc forms brass1 which is harder than copper alone4 ,it tarnishes1 though not so easily as copper2 but a coat of varnish will protect it till the varnish wears off4 ,a good way to find out the many uses of brass and to see how valuable they are is to go along the street and through a house and make a list4 ,on the street you will see signs1 harness buckles1 and buttons1 everywhere4 ,look on the automobiles and fire engines for a fine display of brass1 polished and shining4 ,in the house you will find brass bedsteads1 curtain rods1 faucets1 pipes1 drawerpulls1 candlesticks1 gas and electric fixtures1 lamps1 the works of clocks and watches1 and scores of other things4 ,you will not have any idea how many they are till you begin to count4 ,copper mixed with tin forms bronze4 ,go into a hardware store and look at the samples of bronze outside of each drawer1 and you will be surprised that there are so many4 ,bronze does not change even when in the open air for ages4 ,that is one reason why it has always been so much used for statues4 ,there are two strange facts about this mixture4 ,one is that bronze is harder than either copper or tin4 ,the other is that if you mix one pint of melted copper with one pint of tin1 the mixture will be less than a quart4 ,just why these things are so1 no one is quite certain4 ,mathematics declares that the whole is equal to the sum of its parts2 but in this one case the whole seems to be less than the sum of its parts4 ,another reason why bronze is so much used for statues is that the castings are smooth4 ,i once went to a foundry to have a brass ornament shaped somewhat like a cone made for a clock4 ,the foundryman formed a mould in clay and poured the melted brass into it4 ,when it had cooled1 the mould was broken off and the ornament taken out2 but it was of no use because it was so full of little hollows that it could not be made smooth without cutting away a great deal of it4 ,the man had to try three times before he succeeded in making one that could be polished4 ,if it had been made of bronze1 there would have been no trouble1 because bronze1 hard as it is after it cools1 flows when it is melted almost as easily as molasses and fills every little nook and corner of the mould4 ,a famous ,latin poet named ,horace1 who lived two thousand years ago1 wrote of his poems1 ,i have reared a monument more lasting than bronze2 and he was right1 for few statues have endured from his day to ours1 but his poems are still read and admired4 ,bells are made of bronze1 about three quarters copper and one quarter tin4 ,it is thought that much copper gives a deep1 full tone1 and that much tin with1 sometimes1 zinc makes the tone sharp4 ,the age of a bell has something to do with its sound being rich and mellow2 but the bellmaker has even more1 for he must understand not only how to cast it1 but also how to tune it4 ,if you tap a large bell1 it will1 if properly tuned1 sound a clear note4 ,tap it just on the curve of the top1 and it will give a note exactly one octave above the first4 ,if the note of the bell is too low1 it can be made higher by cutting away a little from the inner rim4 ,if it is too high1 it can be made lower by filing on the inside a little above the rim4 ,many of the old bells contain the gifts of silver and gold which were thrown in by people who watched their founding4 ,the most famous bell in the ,united ,states is the ,liberty ,bell of ,independence ,hall1 in ,philadelphia1 which rang when ,independence was adopted by ,congress4 ,this was founded in ,england long before the ,revolution and later was melted and founded again in the ,united ,states4 ,it would not be easy to get on without brass and bronze2 but even these alloys are not so necessary as copper by itself4 ,it is so strong that it is used in boiler tubes of locomotives1 as roofing for buildings and railroad coaches1 in the great pans and vats of the sugar factories and refineries4 ,a copper ore called malachite1 which shows many shades of green1 beautifully blended and mingled1 is used for the tops of tables4 ,wooden ships are often copper-bottomed2 that is1 sheets of copper are nailed to that part of the hull which is under water in order to prevent barnacles from making their homes on it1 and so lessening the speed of the vessel4 ,people often say that the latter half of the nineteenth century was the ,age of ,steel1 because so many new uses for steel were found at that time4 ,the twentieth century promises to be the ,age of ,electricity1 and electricity must have copper4 ,formerly iron was used for telegraph wires2 but it needs much more electricity to carry power or light or heat or a telegraphic message over an iron wire than one of copper4 ,moreover1 iron will rust and will not stretch in storms like copper1 and so needs renewing much oftener4 ,electric lighting and the telephone are everywhere1 even on the summits of mountains and in mines a mile below the earth's surface4 ,electric power1 if a waterfall furnishes the electricity1 is the cheapest power known4 ,the common blue vitriol is one form of copper1 and to this we owe many of our electric conveniences4 ,it is used in all wet batteries1 and so it rings our doorbells for us4 ,it also sprays our apple and peach trees1 and is a very valuable article4 ,indeed1 copper in all its forms1 pure and alloyed1 is one of our best and most helpful friends4 ,,ix ,,the ,,new ,,metal1 ,,aluminum ,not many years ago a college boy read about an interesting metal called aluminum4 ,it was as strong as iron1 but weighed only one third as much1 and moisture would not make it rust4 ,it was made of a substance called alumina1 and a ,french chemist had declared that the clay banks were full of it2 and yet it cost as much as silver4 ,it had been used in ,france for jewelry and knicknacks1 and a rattle of it had been presented to the baby son of the ,emperor of ,france as a great rarity4 ,the college boy thought by day and dreamed by night of the metal that was everywhere1 but that might as well be nowhere1 so far as getting at it was concerned4 ,at the age of twenty-one1 the young man graduated1 but even his new diploma could not keep his mind away from aluminum4 ,he borrowed the college laboratory and set to work4 ,for seven or eight months he tried mixing the metal with various substances to see if it would not dissolve4 ,at length he tried a stone from ,greenland called cryolite1 which had already been used for making a kind of porcelain4 ,the name of this stone comes from two ,greek words meaning ice stone1 and it is so called because it melts so easily4 ,the young student melted it and found that it would dissolve alumina4 ,then he ran an electric current through the melted mass1 and there was a deposit of aluminum4 ,this young man1 just out of college1 had discovered a process that resulted in reducing the cost of aluminum from twelve dollars a pound to eighteen cents4 ,meanwhile a ,frenchman of the same age had been working away by himself1 and made the same discovery only two months later4 ,aluminum is now made from a mineral called bauxite1 found chiefly in ,georgia1 ,alabama1 and ,arkansas4 ,mining it is much more agreeable than coal mining1 for the work is done aboveground4 ,the bauxite is in beds or strata which often cover the hills like a blanket4 ,first of all1 the mine is stripped1--that is1 the soil which covers the ore is removed1--and then the mining is done in great steps eight or ten feet high1 if a hill is to be worked4 ,there is some variety in mining bauxite1 for it occurs in three forms4 ,first1 it may be a rock1 which has to be blasted in order to loosen it4 ,second1 it may be in the form of gray or red clay4 ,third1 it occurs in round masses1 sometimes no larger than peas1 and sometimes an inch in diameter4 ,in this form it can easily be loosened with a pickaxe1 and shoveled into cars to be carried to the mill4 ,bauxite is a rather mischievous mineral and sometimes acts as if it delighted in playing tricks upon managers of mines4 ,the ore may not change in the least in its appearance1 and yet it may suddenly have become much richer or much poorer4 ,therefore the superintendent has to give his ore a chemical test every little while to make sure that all things are going on well4 ,this bauxite is purified1 and the result is a fine white powder1 which is pure alumina1 and consists of the metal aluminum and the gas oxygen4 ,cryolite is now melted by electricity4 ,the white powder is put into it1 and dissolves just as sugar dissolves in water4 ,the electricity keeps on working1 and now it separates the alumina into its two parts4 ,the aluminum is a little heavier than the melted cryolite1 and therefore it settles and may be drawn off at the bottom of the melting-pot4 ,there are a good many reasons why aluminum is useful4 ,as has been said it is strong and light and does not rust in moisture4 ,you can beat it into sheets as thin as gold leaf1 and you can draw it into the finest wire4 ,it is softer than silver1 and it can be punched into almost any form4 ,it is the most accommodating of metals4 ,you can hammer it in the cold until it becomes as hard as soft iron4 ,then1 if you need to have it soft again1 it will become so by melting4 ,it takes a fine polish and is not affected1 as silver is1 by the fumes which are thrown off by burning coal2 and so keeps its color when silver would turn black4 ,salt water does not hurt it in the least1 and few of the acids affect it4 ,another good quality is that it conducts electricity excellently4 ,it is true that copper will do the same work with a smaller wire2 but the aluminum is much lighter and so cheap that the larger wire of aluminum costs less than the smaller one of copper1 and its use for this purpose is on the increase4 ,it conducts heat as well as silver4 ,if you put one spoon of aluminum1 one of silver1 and one that is plated into a cup of hot water1 the handles of the first two will almost burn your fingers before the third is at all uncomfortable to touch4 ,illustration3 ,a ,,movie ,,of ,,an ,,aluminum ,,funnel ,courtesy ,the ,aluminum ,cooking ,utensil ,company4 ,seventeen other operations are necessary after the thirteenth stamping operation before the funnel is ready to be sold4 ,and after all this work1 we can buy it for #ce cents at any hardware store4 ,aluminum is found not only in clay and indeed in most rocks except sandstone and limestone1 but also in several of the precious stones1 in the yellow topaz1 the blue sapphire and lapis-lazuli1 and the red garnet and ruby4 ,it might look down upon some of its metallic relatives1 but it is friendly with them all1 and perfectly willing to form alloys with most of them4 ,a single ounce of it put into a ton of steel as the latter is being poured out will drive away the gases which often make little holes in castings4 ,mixed with copper it makes a beautiful bronze which has the yellow gleam of gold1 but is hard to work4 ,when a piece of jewelry looks like gold1 but is sold at too low a price to be real1 it may be aluminum bronze1 very pretty at first1 but before long its luster will vanish4 ,aluminum bronze is not good for jewelry1 but it is good for many uses1 especially for bearings in machinery4 ,aluminum mixed with even a very little silver has the color and brightness of silver4 ,the most common alloys with aluminum are zinc1 copper1 and manganese1 but in such small quantities that they do not change its appearance4 ,with so many good qualities and so few bad ones1 it is small wonder that aluminum is employed for more purposes than can be counted4 ,a very few years ago it was only an interesting curiosity1 but now it is one of the hardest-worked metals4 ,automobiles in particular owe a great deal to its help4 ,when they first began to be common1 in #aijd-je1 the engines were less powerful than they are now made1 and aluminum was largely employed in order to lessen the weight4 ,before long it was in use for carburetors1 bodies1 gear-boxes1 fenders1 hoods1 and many other parts of the machine4 ,makers of electric apparatus use aluminum instead of brass4 ,the frames of opera glasses and of cameras are made of it4 ,travelers and soldiers and campers1 people to whom every extra ounce of weight counts1 are glad enough to have dishes of aluminum4 ,the accommodating metal is even used for wallpaper1 and threads of it are combined with silk to give a specially brilliant effect on the stage4 ,it can be made into a paint which will protect iron from rust2 and will make woodwork partially fireproof4 ,aluminum has been gladly employed by the manufacturers of all sorts of articles1 but nowhere has its welcome been more cordial than in the kitchen4 ,any one who has ever lifted the heavy iron kettles which were in use not so very many years ago will realize what an improvement it is to have kettles made of aluminum4 ,but aluminum has other advantages besides its lightness4 ,if any food containing a weak acid1 like vinegar and water1 is put into a copper kettle1 some of the copper dissolves and goes into the food2 acid does not affect aluminum except to brighten it if it has been discolored by an alkali like soda4 ,tin dishes1 so called1 are only iron with a coating of tin4 ,the tin soon wears off1 and the iron rusts2 aluminum does not rust in moisture4 ,a strong alkali will destroy it1 but no alkali in common use in the kitchen is strong enough to do more harm than to change the color1 and a weak acid will restore that4 ,enameled ware1 especially if it is white1 looks dainty and attractive2 but the enamel is likely to chip off1 and1 too1 if the dish boils dry1 the food in it and the dish itself are spoiled4 ,aluminum never chips1 and it holds the heat in such a manner as to make all parts of the dish equally hot4 ,food1 then1 is not so likely to burn down1 but if it does1 only the part that sticks will taste scorched2 and no matter how many times a dish boils dry1 it will never break4 ,if you make a dent in it1 you can easily pound it back into shape again4 ,it is said that an aluminum teakettle one sixteenth of an inch in diameter can be bent almost double before it will break4 ,aluminum dishes are made in two ways4 ,sometimes they are cast1 and sometimes they are drawn on a machine4 ,if one is to be smaller at the top1 as in the case of a coffeepot1 it is drawn out into a cylinder1 then put on a revolving spindle4 ,as it whirls around1 a tool is held against it wherever it is to be made smaller1 and very soon the coffeepot is in shape4 ,the spout is soldered on1 but even the solder is made chiefly of aluminum4 ,aluminum dishes may become battered and bruised1 but they need never be thrown away4 ,there is an old story of some enchanted slippers which brought misfortune to whoever owned them4 ,the man who possessed them tried his best to get rid of the troublesome articles1 but they always returned4 ,so it is with an aluminum dish4 ,bend it1 burn it1 put acid into it1 do what you will to get rid of it1 but like the slippers it remains with you4 ,unlike them1 however1 it brings good fortune1 because it saves time and trouble and patience and money4 ,a few years ago the motive power for most manufactures was steam4 ,electricity is rapidly taking its place2 and if aluminum was good for nothing else save to act as a conductor of electricity in its various applications1 there would even then be a great future before it4 ,x ,,the ,,oil ,,in ,,our ,,lamps ,probably the first man who went to a spring for a drink and found oil floating on the water was decidedly annoyed4 ,he did not care in the least where the oil came from or what it was good for2 he was thirsty1 and it had spoiled his drink1 and that was enough for him4 ,we know now that oil comes chiefly from strata of coarse sandstone1 but we are not quite sure how it happened to be there4 ,the sand which formed these strata was deposited by water ages and ages ago--we are certain of that4 ,another thing that we are certain of is that where the strata lie flat1 there is no oil4 ,hot substances become smaller as they cool2 and as the earth grew cooler1 it became smaller4 ,the crust of the earth wrinkled as the skin of an apple does when it dries4 ,in the tops of these great sandstone wrinkles there is often gas2 and below the gas is the place where oil is found4 ,there is no use in looking for petroleum where the folds of the strata are very sharp1 because in that case the strata crack and let the oil flow away4 ,it is not in pools1 but the porous stone holds it just as a sponge holds water4 ,if you drop a little oil upon a stone even much less porous than sandstone1 it will not be easy to wipe it off1 because some of it will have sunk into the stone4 ,in many places the gas forces its way out1 and is piped to carry to houses for light and heat4 ,not far above ,niagara ,falls there was a spring of gas which flowed for years4 ,an iron pipe was put down1 and when the gas was lighted1 the flame shot up three or four feet4 ,the gas came with such force that a handkerchief put over the end of the pipe would not burn1 though the flame would blaze away above it4 ,in the country of the fire worshipers1 on the shores of the ,caspian ,sea1 fires of natural gas have been burning for ages1 kindled1 perhaps1 by lightning centuries ago4 ,there is a vast supply of oil in this place2 and indeed there is hardly a country that has not more or less of it4 ,in the ,united ,states the colonists soon learned that there was petroleum in what is now the ,state of ,new ,york2 but ,new ,york was a long way from the ,atlantic seaboard in those days1 and they went on contentedly burning candles or sperm whale oil1 or1 a little later1 a rather dangerous liquid which was known as fluid4 ,the ,indians believed that the oil which appeared in the springs was a good medicine4 ,they threw their blankets upon the water1 and when these had become saturated with the oil1 they wrung them out and sold the oil4 ,those were the times when if a medicine only tasted and smelled bad enough1 people never doubted that it would cure all their diseases1 and they gladly bought the oil of the ,indians4 ,when at last it became clear to the members of an enterprising company that oil for use in lamps could be made from petroleum1 they secured some land in ,pennsylvania that seemed promising and set to work to dig a well4 ,but the more they dug1 the more the loose dirt fell in upon them4 ,fortunately for the company1 the superintendent had brains1 and he thought out a way to get the better of the crumbling soil4 ,he simply drove down an iron pipe to the sandstone which contained the oil1 and set his borer at work within the pipe4 ,one morning he found that the oil had gushed in nearly to the top of the well4 ,he had struck oil4 ,this was about ten years after the rush to ,california for gold1 and now that this cheaper and quicker method of making a well had been invented1 there was almost as much of a rush to ,pennsylvania for oil4 ,with every penny that they could beg or borrow1 people from the ,east hurried to the westward to buy or lease a piece of land in the hope of making their fortunes4 ,a song of the day had for its refrain1-- ,stocks par1 stocks up1 ,then on the wane2 ,everybody's troubled with ,oil on the brain4 ,in the course of a year or two1 the first gusher was discovered4 ,the workmen had drilled down some four or five hundred feet and were working away peacefully1 when a furious stream of oil burst forth which hurled the tools high up into the air4 ,hundreds of barrels gushed out every day1 and soon other gushers were discovered4 ,the most famous one in the world is at ,lakeview1 ,california4 ,for months it produced fifty thousand barrels of oil a day1 and threw it up three hundred and fifty feet into the air in a black column1 spraying the country with oil for a mile around4 ,the oil flowed away in a river1 and for a time no one could plan any way to stop it or store it4 ,at last1 however1 a mammoth tank was built around the well and made firm with stones and bags of earth4 ,this was soon full of oil2 and with all this vast weight of oil pressing down upon it1 the stream could not rise more than a few feet above the surface4 ,just why oil should come out with such force1 the geologists are not quite certain2 but it is thought to result from a pressure of gas upon the sandstone containing it4 ,the flow almost always becomes less and less1 and after a time the most generous well has to be pumped4 ,illustration3 ,a ,,california ,,oil ,,field ,for scenery1 one should not go to an oil field4 ,looks1 smell1 and oil alike are unpleasant1 but every oil derrick covers a fortune and helps to make our machinery run smoothly4 ,an oil field may extend over thousands of square miles2 but within this field there are always pools2 that is1 certain smaller fields1 where oil is found4 ,when a man thinks there is oil in a certain spot1 sometimes he buys the land if he is able2 but oftener he gets permission of the owner to bore a well1 agreeing to pay him a royalty2 that is1 a certain percentage of all the oil that is produced4 ,when this has been arranged1 he builds his derrick4 ,this consists of four strong upright beams firmly held together by crossbeams4 ,it stands directly over the place where the well is to be dug4 ,it is from thirty to eighty feet in height1 according to the depth at which it is hoped to find oil4 ,there must also be an engine house to provide the power for drilling4 ,an iron pipe eight or ten inches in diameter is driven down through the soil until it comes to rock4 ,now the regular drilling begins4 ,at the top of the derrick is a pulley4 ,over the pulley passes a stout rope to which the heavy drilling tools--the string of tools1 as they are called--are fastened4 ,the drilling goes on day and night4 ,the drill makes the hole1 and the sand pump sucks out the water and loose bits of stone4 ,when the drill has gone to the bottom of the strata which carry water1 the sides of the bore are cased to keep the water out2 then the drilling continues1 but now the drill makes its way into the oil-bearing sandstone4 ,there is nothing certain about the search for oil4 ,in some places it is near the surface1 in others it is perhaps three or four thousand feet down4 ,the well may prove to be a gusher and pour out hundreds of thousands of gallons a day2 or the oil may refuse to rise to the surface and have to be pumped out even at the first4 ,naturally1 no one is prepared for a gusher1 and millions of gallons have often flowed away before any arrangements could be made for storing the oil4 ,sometimes a well that gives only a moderate flow can be made to yield generously by exploding a heavy charge of dynamite at the bottom1 to break up the rock and1 it is always hoped1 to open some new oil-holding crevice that the drill has not reached4 ,crude petroleum is a dark1 disagreeable1 bad-smelling liquid2 and before it can be of much use1 it must be refined4 ,for several years it was carried in barrels from the oil fields to ,pittsburgh by wagon and boat1 a slow1 expensive process1 and generally unsatisfactory to all but the teamsters4 ,then came the railroads4 ,they provided iron tanks in the shape of a cylinder fastened to freight cars1 much like those employed to-day4 ,there was only one difficulty about sending oil by rail1 and that was that it still had to be hauled by team to the railroad1 sometimes a number of miles4 ,at length1 some one said to himself1 ,why cannot we simply run a pipe directly from the well to the railroad8 ,this was done4 ,pumping engines were put in a few miles apart1 and the invention was a success in the eyes of all but the teamsters4 ,in spite of their opposition1 however1 pipe-lines increased4 ,before this it had been necessary to build the refineries as near the oil regions as possible in order to save the expense of carrying the oil2 but now they could be built wherever it was most convenient4 ,to-day oil can be brought at a small expense from west of the ,mississippi ,river to the ,atlantic seaboard1 refined1 and distributed throughout that part of the country1 or loaded into tankers1--that is1 steamships containing strong tanks of steel1--and so taken across the ocean4 ,the pipes are made of iron and are six or eight inches or more in diameter4 ,in using them one difficulty was found which has been overcome in an ingenious fashion4 ,sometimes they become choked by the impurities of the oil and the flow is lessened4 ,then a go-devil is put into them4 ,this is shaped like a cartridge1 is about three feet in length1 composed of springs and plates of iron and so flexible that it can turn around a corner4 ,it is so made that as it slips down the current of oil1 it whirls around and in so doing its nose of sharp blades scrapes the pipes clean4 ,the pipes go over hills and through swamps4 ,they cross rivers sometimes by means of bridges1 and sometimes they are anchored to the bed of the stream4 ,if they have to go through a salt marsh1 they are laid in concrete to preserve the iron4 ,if these lines were suddenly destroyed and oil had to be carried in the old way1 kerosene would become an expensive luxury4 ,getting the oil out of the ground and carried to the refineries is not all of the business by any means4 ,the early oils crusted on the lamp wicks1 their smell was unendurable1 and they were given to exploding4 ,evidently1 if oil was to be used for lighting1 it must be improved1 and the first step was to distil it4 ,to distil anything means to boil it and collect the vapor4 ,if you hold a piece of cold earthenware in the steam of a teakettle1 water will collect on it4 ,this is distilled water1 and is purer than that in the kettle4 ,petroleum was at first distilled in a rough way2 but now it is done with the utmost care and exactness4 ,the crude oil is pumped into boilers holding six hundred barrels or more4 ,the fires are started1 and the oil soon begins to turn into vapor4 ,this vapor passes through coils of pipe or long1 straight1 parallel pipes4 ,cold water is pumped over these pipes1 the vapor turns into a liquid again1 and we have kerosene oil4 ,this is the outline of the process1 but it is a small part of the actual work in all its details4 ,kerosene oil is only one of the many substances found in petroleum4 ,fortunately1 some of these substances are light1 like gasoline and benzine2 some1 like kerosene1 are heavier2 and paraffin and tar are heaviest of all4 ,there are also gases1 which pass off first and are saved to help keep the furnace going4 ,then come the others1 one by one1 according to their weight4 ,the stillman keeps close watch1 and when the color and appearance of the distillate changes1 he turns it off into another tank4 ,this process is called fractional distillation1 and the various products are called fractions4 ,no two kinds of petroleum and no two oil wells are just alike1 and it needs a skillful man to manage either4 ,even after all this distillation1 the kerosene still chars the wick somewhat--which prevents the wick from drawing up the oil properly--and it still has a disagreeable smell4 ,to fit it for burning in lamps1 it must be treated with sulphuric acid1 which carries away some of the impurities1 and then with caustic soda1 which carries away others4 ,before it can be put on the market1 it is examined to see whether it is of the proper color4 ,then come three important tests4 ,the first is to see that it is of the proper weight4 ,if it is too heavy1 it will not burn freely enough2 if it is too light1 then there is too much of the lighter oils in it for safety4 ,the second test is the flash test4 ,the object of this is to see how hot the oil must be before it gives off a vapor which will burn4 ,the third1 the burning test1 is to discover how hot the oil must be before it will take fire and burn on the surface4 ,most civilized countries make definite laws forbidding the sale of kerosene oil that is not up to a standard of safety4 ,oil for use in lamps should have an open flash test of at least #ajj deg4 ,f4 and a burning point of not less than #abe deg4 ,f4 ,we say that we burn oil in our lamps1 but what we really do is to heat the oil until it gives off gas1 and then we burn the gas4 ,to keep the flame regular and help on the burning1 we use a chimney on the lamp4 ,the hot air rises in the chimney and the cold air underneath rushes in to take its place and brings oxygen to the flame4 ,in a close1 stuffy room no lamp will give a good clear light1 because there is not oxygen enough for its flame4 ,let in fresh air1 and the light will be brighter4 ,if you hold a cold plate in the flame before the chimney is put on1 soot or carbon will be deposited4 ,a lamp gives light because these particles of carbon become so hot that they glow4 ,in lamps using a mantle1 there is the glow not only of these particles1 but also of the mantle4 ,in a wax candle1 we light the wick1 its heat melts the wax and carries it to the flame4 ,when the wax is made hot enough1 it becomes gas1 and we burn the gas1 not the wax4 ,wax alone will melt1 but not take fire even if a burning match is held to it4 ,the reason is that the match does not give heat enough to turn the wax into gas4 ,but put a bit of wax upon a bed of burning coals1 where there is a good supply of heat1 and it will turn into gas and burn4 ,the products made from petroleum are as different in their character and uses as paraffin and naphtha4 ,some of them are used for oiling machinery2 tar is used for dyes2 naphtha dissolves resin to use in varnish2 benzine is the great cleanser of clothes1 printers' types1 and almost everything else2 gasoline runs automobiles1 motors1 and many sorts of engines2 paraffin makes candles1 seals jelly glasses1 covers the heads of matches so that they are no longer spoiled by being wet1 and makes the ever-useful waxed paper2 printers' ink and waterproof roofing-paper both owe a debt to petroleum4 ,even in medicine1 though a little petroleum is no longer looked upon as a cure-all1 vaseline1 one of its products1 is of great value4 ,it can be mixed with drugs without changing their character1 and it does not become rancid4 ,for these reasons1 salves and other ointments can be mixed with it and preserved for years4 ,,xi ,,little ,,grains ,,of ,,salt ,the most interesting mine in the world is that of ,wieliczka in ,poland4 ,in it there are some thirty miles of streets and alleys2 there are churches with pillars1 shrines1 and statues2 there are stairs1 monuments1 and restaurants2 there is a ballroom three hundred feet long and one hundred and ninety feet high1 with beautiful chandeliers1 and in it is a carven throne whereon the ,emperor ,franz ,joseph sat when he visited the mine4 ,there are lakes crossed by ferryboats4 ,there is a railroad station for the mule trains which bear the precious mineral salt1 for this is a salt mine1 and shrines1 statues1 churches1 chandeliers--everything--are all cut out of salt4 ,this mine has been worked for at least eight hundred years and still has salt enough to supply all ,europe for ages4 ,the mass of salt is believed to be five hundred miles long1 fifty miles wide1 and nearly a quarter of a mile thick4 ,it is so pure that it is sold just as it comes from the mine1 either in blocks or finely ground4 ,this mine is a wonderful place to visit1 almost like an enchanted palace1 for as the torchlight strikes the crystals of salt1 they flash and sparkle as if the wall was covered with rubies and diamonds4 ,there is nothing like an enchanted palace in any salt mine of the ,united ,states1 no statues or chapels or chandeliers4 ,there is only a hole in the ground1 where mining is carried on in much the same manner as in other kinds of mines4 ,the shaft is sunk and lined with timbers to keep the dirt from falling in1 just as in other mines4 ,in working salt mines1 however1 water is almost as bad as earth1 and therefore a layer of clay is put between the timbers and the earth4 ,there are the usual galleries and pillars1 with roof and floor of salt4 ,the workmen try to get the salt out in lumps or blocks as far as possible1 and so they bore in drill holes and then blast with dynamite or powder4 ,the salt is loaded upon little cars1 running on tracks1 and is carried up the shaft and to the top of a breaker1 usually more than one hundred feet above the surface of the ground4 ,there it is dumped upon a screen of iron bars1 which lets the fine salt fall through4 ,the large lumps are sold without crushing or sifting1 and are used for cattle and sheep4 ,one of the great deposits of salt is in southeastern ,california4 ,it is thought that the ,gulf of ,california used to run much farther north than it now does1 and that the earth rose1 shutting away part of it from the ocean4 ,this imprisoned water was full of salt4 ,in time it dried1 and the sand blew over it till it was far underground4 ,a better way than digging was found to work it1 as will be seen later2 but while digging was going on1 the workmen built a cottage of blocks of salt1 clear and glassy4 ,the little rain that falls there melted the blocks only enough to unite them firmly together2 and there the house has stood for many years4 ,countries that have no deposits of rock salt can easily get plenty of salt from the water of the ocean if they only have a seacoast4 ,about one thirtieth of the ocean water is salt1 and if the water is evaporated1 the salt can be collected without difficulty4 ,france makes a great deal of salt in this way4 ,when a man goes into the manufacture1 or rather1 the collecting of salt1 he first of all buys or rents a piece of land1--perhaps several acres of it1--that lies just above high water1 and makes it as level as possible4 ,unless it is very firm land1 he covers it with clay1 so that the water will not soak through it4 ,then he divides it into large square basins1 making each a little lower than the one before it4 ,close beside the highest basin he makes a reservoir which at high tide receives water from the ocean4 ,this flows slowly from the reservoir through one basin after another1 becoming more and more salt as the water evaporates4 ,at length the water is gone1 and the salt remains4 ,the workmen take wooden scrapers and push the salt toward the walls of the basins and then shovel it up on the dikes and heap it into creamy cones that sparkle in the sunshine4 ,the dikes are narrow1 raised pathways beside the basins and between them4 ,as you walk along on top of them1 you can smell a faint violet perfume from the salt4 ,thatch is put over the cones to protect them from the rain1 and there they stand till some of the impurities drain away4 ,this salt is not perfectly white1 because the workmen cannot help scraping up a little of the gray or reddish clay with it4 ,most of it is sold as it is1 nevertheless1 for many people have an absurd notion that the darker it is the purer it is4 ,for those who wish to buy white salt it is sent to a refinery to be washed with pure water1 then boiled down and dried4 ,so it is that the sun helps to manufacture salt4 ,in some of the colder countries1 frost does the same work1 but in a very different manner4 ,when salt water freezes1 the water freezes1 but the salt does not1 and a piece of salt water ice is almost as pure as that made of fresh water4 ,of course1 after part of the water in a basin of salt water has been frozen out1 what is left is more salt than it was at first1 and after the freezing has been repeated several times1 only a little water remains1 and evaporation will soon carry this away1 leaving only salt in the basin1 waiting to be purified4 ,not very many years ago one of the encyclopaedias remarked that the deposits of salt in the ,united ,states are unimportant4 ,this was true as far as the working of them was concerned1 but in #aiac the ,united ,states produced more than #cd1jjj1jjj barrels4 ,part of this was made by evaporation of the waters of salt springs1 and a small share from ,great ,salt ,lake in ,utah4 ,the early settlers in ,utah used to gather salt from the shallow bays or lagoons where the water evaporated during the summer2 but now dams of earth hold back the water in a reservoir4 ,in the spring the pumps are put to work and the reservoir is soon filled with water4 ,this is left to stand and give the impurities a chance to settle to the bottom4 ,then it is allowed to flow into smaller basins1 while more water is pumped into the reservoir4 ,when autumn comes1 the crop of salt is ready to be harvested4 ,it is in the form of a crust three to six inches thick1 some of it in large crystals1 and some fine-grained4 ,this crust is broken by ploughs1 and the salt is heaped up into great cones and left for the rain to wash clean4 ,then it goes to the mill for purifying4 ,the water of ,great ,salt ,lake is much more salty than that of the ocean4 ,it preserves timber remarkably well1 and often salt from the lake is put around telephone poles1 seventy-five pounds being dropped into the hole for each one4 ,it has been suggested to soak timber in the ,lake1 and then paint it with creosote to keep the wet out and the salt in4 ,salt is also made from the waters of salt springs1 which the ,indians thought were the homes of evil spirits4 ,at ,salton1 in ,california1 an area of more than one thousand acres1 which lies two hundred and sixty-four feet below sea level1 is flooded with water from salt springs4 ,when this water has evaporated1 all these acres are covered with salt ten to twenty inches thick1 and as dazzlingly white as if it was snow4 ,this great field is ploughed up with a massive four-wheeled implement called a salt-plough4 ,it is run by steam and needs two men to manage it4 ,the heavy steel ploughshare breaks up the salt crust1 making broad1 shallow furrows and throwing the salt in ridges on both sides4 ,the plough has hardly moved on before the crust begins to form again4 ,this broken crust is worked in water by men with hoes in order to remove the bits of earth that stick to it1 then piled up into cones to drain1 loaded upon flat trucks1 and carried to the breaker4 ,the salt fields are wonderfully beautiful in the moonlight1 but not very agreeable to work in1 for the mercury often reaches #adj deg4 ,f41 and the air is so full of particles of salt that the workers feel an intense thirst1 which the warm1 brackish water does not satisfy4 ,the work is done by ,indians and ,japanese1 for white people cannot endure the heat4 ,a large portion of the salt used in the ,united ,states comes directly from rock salt strata1 hundreds of feet below the surface of the ground4 ,these were perhaps the bed of the ocean ages and ages ago4 ,there is a great extent of the beds in ,new ,york1 ,michigan1 ,ohio1 ,kansas1 and other ,states4 ,in ,michigan there is a stratum of rock salt thirty to two hundred and fifty feet thick and some fifteen hundred to two thousand feet below the surface4 ,to mine this would be a difficult and expensive undertaking1 and a far better way has been discovered4 ,first1 a pipe is forced down through the surface dirt1 the limestone1 and the shale to the salt stratum4 ,the drill works inside this pipe and bores a hole for a six-inch pipe directly into the salt4 ,a three-inch pipe is let down inside of the six-inch pipe1 and water is forced down through the smaller pipe4 ,it dissolves the salt1 becomes brine1 and rises through the space between the two pipes4 ,it is carried through troughs to some great tanks1 and from these it flows into grain-settlers1 then into the grainers proper1 where the grains of salt settle4 ,at the bottom of the grainers are steam pipes1 and these make the brine so hot that before long little crystals of salt are seen floating on the surface of the water4 ,crystals form much better if the water is perfectly smooth1 and to bring this about a very little oil is poured into the grainer4 ,it spreads over the surface in the thinnest film that can be imagined4 ,the water evaporates1 and the tiny crystals grow1 one joining to another as they do in rock candy4 ,when they become larger1 they drop to the bottom of the grainer4 ,they are now swept along in a trough to a pocket1 carried up by an endless chain of buckets1 and then wheeled away to the packinghouse4 ,the finest salt is made by using vacuum pans4 ,these are great cans out of which the air is pumped1 and into which the brine flows4 ,this brine1 heated by steam pipes1 begins to boil1 and as the steam from it rises1 it has to pass through a pipe at the top and is thus carried into a small tank into which cold water is flowing4 ,the cold makes the steam condense into water1 which runs off4 ,the condensed water occupies less space than the steam and so maintains the vacuum in the pan4 ,for a perfect vacuum the brine is boiled at less than #ajj deg4 ,f41 while in an open pan or grainer it requires #bbf deg4 to boil brine4 ,the brine is soon so rich in salt that tiny crystals begin to form4 ,these are taken out and dried4 ,if you look at some grains of table salt through a magnifying glass1 you can see that each grain is a tiny cubical crystal4 ,sometimes two or three are united1 and often the corners are rounded off and worn1 but they show plainly that they are little cubes4 ,most of the salt used on our tables is made by the vacuum process or by an improved method which produces tiny flakes of salt similar to snowflakes4 ,the salt brine is heated to a high temperature and filtered4 ,in the filters the impurities are taken out1 and this process gives us very pure salt4 ,the tiny flakes dissolve more easily than the cubes of salt1 and thus flavor food more readily4 ,with a few savage tribes salt is regarded as a great luxury1 but with most peoples it is looked upon as a necessity4 ,some of the early races thought a salt spring was a special gift of the gods1 and in their sacrifices they always used salt4 ,in later times to sit above the salt1 between the great ornamental salt cellar and the master of the house1 was a mark of honor4 ,less distinguished guests were seated below the salt4 ,to eat a man's salt and then be unfaithful to him has always been looked upon as a shameful act2 and with some of the savages1 so long as a stranger ate his salt1--that is1 was a guest in the house of any one of them1--he was safe4 ,to eat salt together is an expression of friendliness4 ,cakes of salt have been used as money in various parts of ,africa and ,asia4 ,attic salt means wit1 because the ,athenians1 who lived in ,attica1 were famous for their keen1 delicate wit4 ,to take a story or a statement with a grain of salt means not to accept it entirely1 but only to believe it partially4 ,when ,christ told his disciples that they were the salt of the earth1 he meant that their lives and teaching would influence others just as salt affects every article of food and changes its flavor4 ,our word salary comes from the ,latin word sal1 meaning salt2 and salarium1 or salt-money1 was money given for paying one's expenses on a journey4 ,living without salt would be a difficult matter4 ,cattle that have been shut away from it for a while are almost wild to get it4 ,farmers living among the mountains sometimes drive their cattle to a mountain pasture to remain there through the summer1 and every little while they go up to salt the animals4 ,the cattle know the call and know that it means salt2 and ,i have seen them come rushing down the mountain-side and through the woods1 over fallen trees1 through briers1 and down slippery rocks1 bellowing as they came1 and plunging head first in a wild frenzy to get to the pieces of rock salt that were waiting for them4 99 99 99 99 99 ,,first ,,year ,,in ,,number #ce cents net4 ,postpaid ,an ,introductory ,book to ,precede any ,series of ,arithmetics ,,by ,,franklin ,s4 ,,hoyt ,formerly ,assistant ,superintendent of ,schools1 ,indianapolis ,,and ,,harriet ,e4 ,,peet ,instructor in ,methods of ,teaching ,arithmetic1 ,state ,normal ,school1 ,salem1 ,massachusetts ,the work is based upon the familiar experiences and activities of children1 and follows as closely as possible the child's own method of acquiring new knowledge and skill4 ,thus we have lessons based on playing store1 making tickets1 mailing letters1 fishing1 etc4 ,every step is made interesting1 but no time is wasted in mere entertainment4 99 99 99 99 99 ,by the same authors ,,the ,,everyday ,,arithmetics ,,three-,,book ,,course ,book ,one1 grades ,,ii-,,iv 4#dj ,book ,two1 grades ,v-,,vi 4#dj ,book ,three1 grades ,,vii-,,viii 4#de ,,two-,,book ,,course ,book ,one1 grades ,,ii-,,iv4 4#dj ,book ,two1 grades ,v-,,viii4 4#gb ,course of ,study 7with answers7 4#be ,distinctive ,features #a4 ,their socialized point of view--all problems and topics taken from the everyday life of children1 home interests1 community interests1 common business and industries4 #b4 ,their attractiveness to children--spirited illustrations1 legible page1 interesting subject matter4 #c4 ,the omission of all antiquated topics and problems4 #d4 ,the grouping of problems about a given life situation4 #e4 ,the development of accuracy and skill in essential processes4 #f4 ,the vocational studies4 #g4 ,the careful attention to method4 #h4 ,the exact grading4 #i4 ,the systematic reviews4 #aj4 ,the adaptation to quick and to slow pupils4 99 99 99 99 99 ,,houghton ,,mifflin ,,company ,,boston ,,new ,,york ,,chicago #aija ,a ,,step ,,forward ,,in ,,reading ,,the ,,riverside ,,readers ,,edited ,,by ,,james ,h4 ,,van ,,sickle ,superintendent of ,schools1 ,springfield1 ,mass4 ,,and ,,wilhelmina ,,seegmiller ,late ,director of ,art1 ,indianapolis4 ,formerly ,principal of the ,wealthy ,avenue ,public ,school1 ,grand ,rapids1 ,mich4 ,,assisted ,,by ,,frances ,,jenkins ,instructor in ,elementary ,education1 ,college for ,teachers1 ,university of ,cincinnati1 ,formerly ,supervisor of ,elementary ,grades1 ,decatur1 ,ill4 ,,illustrated ,,by ,,ruth ,,mary ,,hallock ,,maginel ,,wright ,,enright ,,clara ,e4 ,,atwood ,e4 ,,boyd ,,smith ,,howard ,,pyle1 and other notable artists ,,fresh ,,material ,these ,readers contain an unusually large amount of fresh copyrighted material taken from the world's best literature for children4 ,,latest ,,teaching ,,methods ,they represent the latest developments in the methods of teaching reading1 the kind of teaching that will be found in the best schools of to-day4 ,,artistic ,,make-,,up ,artistically the books will set a new standard in text-book making4 ,the colored ,illustrations of the primary books are particularly attractive4 ,,mechanical ,,features ,the paper used in the books1 the type for each grade1 and the dimensions and arrangement of the type page were all determined by careful experimenting1 in order to safeguard the eyesight of children4 ,send for complete illustrated circular describing the unique plan of this series4 ,,prices ,primer #cj cents1 net4 ,first ,reader #ce cents1 net4 ,second ,reader #dj cents1 net4 ,third ,reader #ej cents1 net4 ,fourth ,reader #ee cents1 net4 ,fifth ,reader #ee cents1 net4 ,sixth ,reader #ee cents1 net4 ,seventh ,reader #ee cents1 net4 ,eighth ,reader1 #fj cents1 net4 99 99 99 99 99 ,,houghton ,,mifflin ,,company ,,boston ,,new ,,york ,,chicago #aija 99 99 99 99 99 ,transcriber's ,notes ,the ,list of ,illustrations was added1 and some of the illustrations have been moved from their original positions to avoid breaking up paragraphs of text4