Chapter 8

This metal in color is white and next in luster to silver. It has never been found in a pure state, but is known to exist in combination with nearly two hundred different minerals. Corundum and pure emery are ores that are very rich in aluminum, containing about fifty-four per cent. The specific gravity is but two and one-half times that of water; it is lighter than glass or as light as chalk, being only one-third the weight of iron and one-fourth the weight of silver; it is as malleable as gold, tenacious as iron, and harder than steel, being next the diamond. Thus it is capable of the widest variety of uses, being soft when ductility, fibrous when tenacity, and crystalline when hardness is required. Its variety of transformations is something wonderful. Meeting iron, or even iron at its best in the form of steel, in the same field, it easily vanquishes it at every point. It melts at 1,300 degrees F., or at least 600 degrees below the melting point of iron, and it neither oxidizes in the atmosphere nor tarnishes in contact with gases. The enumeration of the properties of aluminum is as enchanting as the scenes of a fairy tale.

Before proceeding further with this new wonder of science, which is already knocking at our doors, a brief sketch of its birth and development may be fittingly introduced. The celebrated French chemist Lavoisier, a very magician in the science, groping in the dark of the last century, evolved the chemical theory of combustion--the existence of a "highly respirable gas," oxygen, and the presence of metallic bases in earths and alkalies. With the latter subject we have only to do at the present moment. The metallic base was predicted, yet not identified. The French Revolution swept this genius from the earth in 1794, and darkness closed in upon the scene, until the light of Sir Humphry Davy's lamp in the early years of the present century again struck upon the metallic base of certain earths, but the reflection was so feeble that the great secret was never revealed. Then a little later the Swedish Berzelius and the Danish Oersted, confident in the prediction of Lavoisier and of Davy, went in search of the mysterious stranger with the aggressive electric current, but as yet to no purpose. It was reserved to the distinguished German Wohler, in 1827, to complete the work of the past fifty years of struggle and finally produce the minute white globule of the pure metal from a mixture of the chloride of aluminum and sodium, and at last the secret is revealed--the first step was taken. It took twenty years of labor to revolve the mere discovery into the production of the aluminum bead in 1846, and yet with this first step, this new wonder remained a foetus undeveloped in the womb of the laboratory for years to come.

Returning again to France some time during the years between 1854 and 1858, and under the patronage of the Emperor Napoleon III., we behold Deville at last forcing Nature to yield and give up this precious quality as a manufactured product. Rose, of Berlin, and Gerhard, in England, pressing hard upon the heels of the Frenchman, make permanent the new product in the market at thirty-two dollars per pound. The despair of three-quarters of a century of toilsome pursuit has been broken, and the future of the metal has been established.

The art of obtaining the metal since the period under consideration has progressed steadily by one process after another, constantly increasing in powers of productivity and reducing the cost. These arts are intensely interesting to the student, but must be denied more than a reference at this time. The price of the metal may be said to have come within the reach of the manufacturing arts already.

A present glance at the uses and possibilities of this wonderful metal, its application and its varying quality, may not be out of place. Its alloys are very numerous and always satisfactory; with iron, producing a comparative rust proof; with copper, the beautiful golden bronze, and so on, embracing the entire list of articles of usefulness as well as works of art, jewelry, and scientific instruments.

Its capacity to resist oxidation or rust fits it most eminently for all household and cooking utensils, while its color transforms the dark visaged, disagreeable array of pots, pans, and kitchen implements into things of comparative beauty. As a metal it surpasses copper, brass, and tin in being tasteless and odorless, besides being stronger than either.

It has, as we have seen, bulk without weight, and consequently may be available in construction of furniture and house fittings, as well in the multitudinous requirements of architecture. The building art will experience a rapid and radical change when this material enters as a component material, for there will be possibilities such as are now undreamed of in the erection of homes, public buildings, memorial structures, etc. etc., for in this metal we have the strength, durability, and the color to give all the variety that genius may dictate.

And when we take a still further survey of the vast field that is opening before us, we find in the strength without size a most desirable assistant in all the avenues of locomotion. It is the ideal metal for railway traffic, for carriages and wagons. The steamships of the ocean of equal size will double their cargo and increase the speed of the present greyhounds of the sea, making six days from shore to shore seem indeed an old time calculation and accomplishment. A thinner as well as a lighter plate; a smaller as well as a stronger engine; a larger as well as a less hazardous propeller; and a natural condition of resistance to the action of the elements; will make travel by water a forcible rival to the speed attained upon land, and bring all the distant countries in contact with our civilization, to the profit of all. This metal is destined to annihilate space even beyond the dream of philosopher or poet.

The tensile strength of this material is something equally wonderful, when wire drawn reaches as high as 128,000 pounds, and under other conditions reaches nearly if not quite 100,000 pounds to the square inch. The requirements of the British and German governments in the best wrought steel guns reach only a standard of 70,000 pounds to the square inch. Bridges may be constructed that shall be lighter than wooden ones and of greater strength than wrought steel and entirely free from corrosion. The time is not distant when the modern wonder of the Brooklyn span will seem a toy.

It may also be noted that this metal affords wide development in plumbing material, in piping, and will render possible the almost indefinite extension of the coming feature of communication and exchange--the pneumatic tube.

The resistance to corrosion evidently fits this metal for railway sleepers to take the place of the decaying wooden ties. In this metal the sleeper may be made as soft and yielding as lead, while the rail may be harder and tougher than steel, thus at once forming the necessary cushion and the avoidance of jar and noise, at the same time contributing to additional security in virtue of a stronger rail.

In conductivity this metal is only exceeded by copper, having many times that of iron. Thus in telegraphy there are renewed prospects in the supplanting of the galvanized iron wire--lightness, strength, and durability. When applied to the generation of steam, this material will enable us to carry higher pressure at a reduced cost and increased safety, as this will be accomplished by the thinner plate, the greater conductivity of heat, and the better fiber.

It is said that some of its alloys are without a rival as an anti-friction metal, and having hardness and toughness, fits it remarkably for bearings and journals. Herein a vast possibility in the mechanic art lies dormant--the size of the machine may be reduced, the speed and the power increased, realizing the conception of two things better done than one before. It is one of man's creative acts.

From other of its alloys, knives, axes, swords, and all cutting implements may receive and hold an edge not surpassed by the best tempered steel. Hulot, director in the postage stamp department, Paris, asserts that 120,000 blows will exhaust the usefulness of the cushion of the stamp machine, and this number of blows is given in a day; and that when a cushion of aluminum bronze was substituted, it was unaffected after months of use.

If we have found a metal that possesses both tensile strength and resistance to compression; malleability and ductility--the quality of hardening, softening, and toughening by tempering; adaptability to casting, rolling, or forging; susceptibility to luster and finish; of complete homogeneous character and unusually resistant to destructive agents--mankind will certainly leave the present accomplishments as belonging to an effete past, and, as it were, start anew in a career of greater prospects.

This important material is to be found largely in nearly all the rocks, or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal." It is in every clay bank. It is particularly abundant in the coal measures and is incidental to the shales or slates and clays that underlie the coal. This under clay of the coal stratum was in all probability the soil out of which grew the vegetation of the coal deposits. It is a compound of aluminum and other matter, and, when mixed with carbon and transformed by the processes of geologic action, it becomes the shale rock which we know and which we discard as worthless slate. And it is barely possible that we have been and are still carting to the refuse pile an article more valuable than the so greatly lauded coal waste or the merchantable coal itself. We have seen that the best alumina ore contains only fifty-four per cent. of metal.

The following prepared table has been furnished by the courtesy and kindness of Mr. Alex. H. Sherred, of Scranton.

ALUMINA.

Blue-black shale, Pine Brook drift 27.36 Slate from Briggs' Shaft coal 15.93 Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 First cut on railroad, black clay above Rolling Mill 32.60 G vein black clay, Hyde Park mines 28.67

It will be seen that the black clay, shale, or slate, has a constituent of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the highest. Under every stratum of coal, and frequently mixed with it, are these under deposits that are rich in the metal. When exposed to the atmosphere, these shales yield a small deposit of alum. In the manufacture of alum near Glasgow the shale and slate clay from the old coal pits constitute the material used, and in France alum is manufactured directly from the clay.

Sufficient has been advanced to warrant the additional assertion that we are here everywhere surrounded by this incomparable mineral, that it is brought to the surface from its deposits deep in the earth by the natural process in mining, and is only exceeded in quantity by the coal itself. Taking a columnar section of our coal field, and computing the thickness of each shale stratum, we have from twenty-five to sixty feet in thickness of this metal-bearing substance, which averages over twenty-five per cent. of the whole in quantity in metal.

It is readily apparent that the only task now before us is the reduction of the ore and the extraction of the metal. Can this be done? We answer, it has been done. The egg has stood on end--the new world has been sighted. All that now remains is to repeat the operation and extend the process. Cheap aluminum will revolutionize industry, travel, comfort, and indulgence, transforming the present into an even greater civilization. Let us see.

We have seen the discovery of the mere chemical existence of the metal, we have stood by the birth of the first white globule or bead by Wohler, in 1846, and witnesssed its introduction as a manufactured product in 1855, since which time, by the alteration and cheapening of one process after another, it has fallen in price from thirty-two dollars per pound in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent labor at smelting have increased the quantity over a thousandfold and reduced the cost upward of fifty per cent.

All these processes involve the application of heat--a mere question of the appliances. The electric currents of Berzelius and Oersted, the crucible of Wohler, the closed furnaces and the hydrogen gas of the French manufacturers and the Bessemer converter apparatus of Thompson, all indicate one direction. This metal can be made to abandon its bed in the earth and the rock at the will of man. During the past year, the Messrs. Cowles, of Cleveland, by their electric smelting process, claim to have made it possible to reduce the price of the metal to below four dollars per pound; and there is now erecting at Lockport, New York, a plant involving one million of capital for the purpose.

Turning from the employment of the expensive reducing agents to the simple and sole application of heat, we are unwilling to believe that we do not here possess in eminence both the mineral and the medium of its reduction. Whether the electric or the reverberatory or the converter furnace system be employed, it is surely possible to produce the result.

To enter into consideration of the details of these constructions would involve more time than is permitted us on this occasion. They are very interesting. We come again naturally to the limitless consideration of powdered fuel, concerning which certain conclusions have been reached. In the dissociation of water into its hydrogen and oxygen, with the mingled carbon in a powdered state, we undoubtedly possess the elements of combustion that are unexcelled on earth, a heat-producing combination that in both activity and power leaves little to be desired this side of the production of the electric force and heat directly from the carbon without the intermediary of boilers, engines, dynamos, and furnaces.

In the hope of stimulating thought to this infinite question of proper fuel combustion, with its attendant possibilities for man's gratification and ambition, this advanced step is presented. The discussion of processes will require an amount of time which I hope this Board will not grudgingly devote to the subject, but which is impossible at present. Do not forget that there is no single spot on the face of the globe where nature has lavished more freely her choicest gifts. Let us be active in the pursuit of the treasure and grateful for the distinguished consideration.

* * * * *

THE ORIGIN OF METEORITES.

On January 9, Professor Dewar delivered the sixth and last of his series of lectures at the Royal Institution on "The Story of a Meteorite." [For the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that cosmic dust is found on Arctic snows and upon the bottom of the ocean; all over the world, in fact, at some time or other, there has been a large deposit of this meteoric dust, containing little round nodules found also in meteorites. In Greenland some time ago numbers of what were supposed to be meteoric stones were found; they contained iron, and this iron, on being analyzed at Copenhagen, was found to be rich in nickel. The Esquimaux once made knives from iron containing nickel; and as any such alloy they must have found and not manufactured, it was supposed to be of meteoric origin. Some young physicists visited the basaltic coast in Greenland from which some of the supposed meteoric stones had been brought, and in the middle of the rock large nodules were found composed of iron and nickel; it, therefore, became evident that the earth might produce masses not unlike such as come to us as meteorites. The lecturer here exhibited a section of the Greenland rock containing the iron, and nickel alloy, mixed with stony crystals, and its resemblance to a section of a meteorite was obvious. It was 2½ times denser than water, yet the whole earth is 5½ times denser than water, so that if we could go deep enough, it is not improbable that our own globe might be found to contain something like meteoric iron. He then called attention to the following tables:

_Elementary Substances found in Meteorites_.

Hydrogen. Chromium. Arsenic. Lithium. Manganese. Vanadium? Sodium. Iron. Phosphorus. Potassium. Nickel. Sulphur. Magnesium. Cobalt. Oxygen. Calcium. Copper. Silicon. Aluminum. Tin. Carbon. Titanium. Antimony. Chlorine.

_Density of Meteorites_.

Carbonaceous (Orgueil, etc.) 1.9 to 3 Aluminous (Java) 3.0 " 3.2 Peridotes (Chassigny, etc.) 3.5 " -- Ordinary type (Saint Mes) 3.1 " 3.8 Rich in iron (Sierra de Chuco) 6.5 " 7.0 Iron with stone (Krasnoyarsk) 7.1 " 7.8 True irons (Caille) 7.0 " 8.0

_Interior of the Earth_

Parts of the radius. Density. 0.0 11.0 0.1 10.3 0.2 9.6 0.3 8.9 0.4 8.3 0.5 7.8 0.6 7.4 0.7 7.1 0.8 6.2 0.9 5.0 1.0 2.6

Twice a year, said Professor Dewar, what are called "falling stars" maybe plentifully seen; the times of their appearance are in August and November. Although thousands upon thousands of such small meteors have passed through our atmosphere, there is no distinct record of one having ever fallen to the earth during these annual displays. One was said to have fallen recently at Naples, but on investigation it turned out to be a myth. These annual meteors in the upper air are supposed to be only small ones, and to be dissipated into dust and vapor at the time of their sudden heating; so numerous are they that 40,000 have been counted in one evening, and an exceptionally great display comes about once in 33¼ years. The inference from their periodicity is, that they are small bodies moving round the sun in orbits of their own, and that whenever the earth crosses their orbits, thereby getting into their path, a splendid display of meteors results. A second display, a year later, usually follows the exceptionally great display just mentioned, consequently the train of meteors is of great length. Some of these meteors just enter the atmosphere of the earth, then pass out again forever, with their direction of motion altered by the influence of the attraction of the earth. He here called attention to the accompanying diagram of the orbits of meteors.

The lecturer next invited attention to a hollow globe of linen or some light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and contained hidden within it the great electro-magnet, weighing 2 cwt., so often used by Faraday in his experiments. He also exhibited a ball made partly of thin iron; the globe represented the earth, for the purposes of the experiment, and the ball a meteorite of somewhat large relative size. The ball was then discharged at the globe from a little catapult; sometimes the globe attracted the ball to its surface, and held it there, sometimes it missed it, but altered its curve of motion through the air. So was it, said the lecturer, with meteorites when they neared the earth. Photographs from drawings, by Professor A. Herschel, of the paths of meteors as seen by night were projected on the screen; they all seemed to emanate from one radiant point, which, said the lecturer, is a proof that their motions are parallel to each other; the parallel lines seem to draw to a point at the greatest distance, for the same reason that the rails of a straight line of railway seem to come from a distant central point. The most interesting thing about the path of a company of meteors is, that a comet is known to move in the same orbit; the comet heads the procession, the meteors follow, and they are therefore, in all probability, parts of comets, although everything about these difficult matters cannot as yet be entirely explained; enough, however, is known to give foundation for the assumption that meteorites and comets are not very dissimilar.

The light of a meteorite is not seen until it enters the atmosphere of the earth, but falling meteorites can be vaporized by electricity, and the light emitted by their constituents be then examined with the spectroscope. The light of comets can be directly examined, and it reveals the presence in those bodies of sodium, carbon, and a few other well-known substances. He would put a piece of meteorite in the electric arc to see what light it would give; he had never tried the experiment before. The lights of the theater were then turned down, and the discourse was continued in darkness; among the most prominent lines visible in the spectrum of the meteorite, Professor Dewar specified magnesium, sodium, and lithium. "Where do meteorites come from?" said the lecturer. It might be, he continued, that they were portions of exploded planets, or had been ejected from planets. In this relation, he should like to explain the modern idea of the possible method of construction of our own earth. He then set forth the nebular hypothesis that at some long past time our sun and all his planets existed but as a volume of gas, which in contracting and cooling formed a hot volume of rotating liquid, and that as this further contracted and cooled, the planets, and moons, and planetary rings fell off from it and gradually solidified, the sun being left as the solitary comparatively uncooled portion of the original nebula. In partial illustration of this, he caused a little globe of oil, suspended in an aqueous liquid of nearly its own specific gravity, to rotate, and as it rotated it was seen, by means of its magnified image upon the screen, to throw off from its outer circumference rings and little globes.

* * * * *

CANDELABRA CACTUS AND CALIFORNIA WOODPECKER.

By C.F. HOLDER.

One of the most picturesque objects that meet the eye of the traveler over the great plains of the southern portion of California and New Mexico is the candelabra cactus. Systematically it belongs to the Cereus family, in which the notable Night-blooming Cereus also is naturally included. In tropical or semi-tropical countries these plants thrive, and grow to enormous size. For example, the Cereus that bears those great flowers, and blooms at night, exhaling powerful perfume, as we see them in hothouses in our cold climate, are even in the semi-tropical region of Key West, on the Florida Reef, seen to grow enormously in length.

We cultivated several species of the more interesting forms during a residence on the reef. Our brick house, two stories in height, was entirely covered on a broad gable end, the branches more than gaining the top. There is a regular monthly growth, and this is indicated by a joint between each two lengths. Should the stalk be allowed to grow without support, it will continue growing without division, and exhibit stalks five or six feet in length, when they droop, and fall upon the ground.