Electricity and Magnetism Part 10

There are a number of these chambers, so that the operation in all of its phases is going on continuously. The room where the chlorine gas is formed is thoroughly ventilated, a precaution which is very necessary in case any one of the vats should spring a leak, as they sometimes do.

In each one of these vats where the electrolytic process is going on there are two products constantly pa.s.sing off; one, as before mentioned, is chlorine gas, and the other caustic soda in solution. The solution in the vat is constantly being renewed by the saturated solution of salt from the reservoir before mentioned. There is one stream continuously coming into the vat and two going out, caused by the decomposing power of the electric current. The solution of caustic soda is carried to large evaporating-pans, where the water is driven out of it, leaving the caustic soda in dry, white sticks of crystalline formation. In this process the electric current, which comes from the power-house with an energy of 2000 horse-power, has to be transformed twice; first, to bring it to the proper voltage for the work of decomposition, and, secondly, to change it from an alternating to a direct current, by which all electrolytic processes are carried on.

You will notice that the electrical energy expended in this establishment is double that used in the manufacture of carborundum.

The caustic soda, which is one of the products from the decomposition of salt, is taken to another establishment, where, by still another electrical process, metallic sodium is manufactured. The process here being a secret one, the writer did not have the privilege of examining the details.

CHAPTER XXVII

ELECTRICAL PRODUCTS--ALUMINUM.

Another comparatively new article of manufacture now produced in large quant.i.ties at Niagara Falls is aluminum. Until within the last few years this metal was not used to any extent by manufacturers, because of the great expense attending its production. Now, however, it is produced in such quant.i.ties as to make it about as cheap as bra.s.s, bulk for bulk.

Aluminum is a very light metal, with a color somewhat lighter than silver; its specific gravity being about one-third that of iron.

Aluminum is found in one of its compounds in great quant.i.ties in nature, especially in certain kinds of clay and in a state of silicate, as in feldspar and its a.s.sociated minerals. It is found in great quant.i.ties in southern Georgia, where it is mixed with the red oxide of iron that abounds in that region. Here, it exists as alumina, which is an oxide of aluminum. Before it is taken to the reduction-works the alumina is separated from all other substances. It is a white powder, tasteless, and not easily acted upon by acids.

Electricity is the chief agent in the production of metallic aluminum.

The reduction company buys this alumina, which has been separated from the clay or ores where it is mined. In a large room there are located a great number of iron vats or crucibles, lined with carbon, about two or two and one-half feet deep, five or six feet long and four feet wide.

Immediately over each vat is constructed a metal framework, through which are inserted a large number of carbon rods about eighteen or twenty inches long and from two to two and one-half inches in diameter.

This framework is electrically insulated from the iron crucibles. The framework and the carbons are connected with the positive conductor of the electric current, and the vat or crucible with the negative. These conductors are very large, something like a foot in width and an inch in thickness, and made of some good conductor of electricity. They have to be very large because they carry a current equal to 3050 horse-power.

The current is one of great volume, but very low voltage; the electromotive force at each vat or crucible being only about seven volts. As the process is electrolytic, and not simply a heating process, the direct current must be used, and therefore the current coming from the power-house must be transformed twice; first to bring it to a proper voltage and secondly to change it from an alternating to a direct current. These iron vats or crucibles are connected up in series, electrically, and then they are filled with the alumina and certain other materials, which act either as a flux or as a means of increasing the conductivity of the mixture; just what this substance is, is probably one of the secrets of the process. When all of the crucibles are filled with the mixture the current is turned on and is kept on continuously night and day seven days in the week. All of the material in the different crucibles is heated to redness, when the process of separation takes place. The oxygen of the alumina is thrown off as a gas, and other residuum floats to the top of the crucible and is skimmed off.

Metallic aluminum in a melted state sinks to the bottom of the crucible, where it is dipped out from time to time with large iron ladles and poured into sand and molded into blocks similar to that of pig iron.

From time to time, as the metal is dipped out, fresh alumina with the other substances are thrown in on top of the crucible, so that the process is continually going on, day and night, week in and week out.

The heat in the process of reducing alumina, as we have before seen, is not the chief factor; it simply serves to reduce the compound to a fluid state so that the electrolytic action can readily take place.

Therefore it is not necessary to be brought to a white heat, as it is in the case of the production of carborundum, described elsewhere.

It was extremely interesting to observe the wonderful magnetic effects that were produced in iron when brought into proximity with these enormous electrical conductors. The voltage was so low that one could handle them with impunity. The iron crucibles became so magnetic that a heavy bar of iron seven or eight feet long would cling to their sides, so that it would be held in an upright position. Bars of iron would cling to the conductor at any point along its length, and, although these conductors were carrying an energy of over 3000 horse-power, they produced no perceptible effect upon the human body. The reason for this lies in the fact, first, that the body is not made of magnetic material, and, secondly, the pressure is so low that the body--being a poor conductor--would not easily allow the low-pressure current to pa.s.s through it.

Aluminum is fast becoming an important article of commerce, and it is destined to become more and more so on account of its extreme lightness as compared to other metals.

It is found to be valuable also when used as an alloy with many of the other metals. One of the great drawbacks to its more extensive use lies in the fact that as yet no satisfactory method has been devised for soldering it. Undoubtedly in time this difficulty will be solved, when its use will be greatly increased. It is estimated that in its various compounds aluminum forms about one-twelfth of the crust of the earth.

CHAPTER XXVIII.

ELECTRICAL PRODUCTS--CALCIUM CARBIDE.

Another important use to which electricity is put at Niagara Falls is the manufacture of a new product, called calcium carbide. Like carborundum and aluminum, this product could not have been produced in commercial quant.i.ties in advance of a means for producing electricity in enormous volume.

Calcium carbide is a compound of calcium and carbon. Calcium is a white metal not found in the natural state, but exists chiefly as a carbonate of lime, which is ordinary limestone, including the various forms of marble. As a pure metal it is hard to obtain and very hard to maintain, as it readily oxidizes when in contact with the air. The symbol for calcium carbide is CaC_{2}, which means that a molecule of this carbide is compounded of one atom of calcium and two atoms of carbon. Ca stands for calcium and C for carbon. When the symbol has no figure following it, it means that one atom only enters into the compound; but if a figure follows, it means that as many atoms enter in as the figure represents.

The process of manufacturing calcium carbide is as follows: Ordinary lime before it is slacked is ground to a fine powder; then it is mixed with powdered c.o.ke or carbon in the proper quant.i.ties, so that when a chemical union takes place the proportion will be as before stated, one atom of calcium to two of carbon. As is well known, lime is procured by exposing ordinary limestone to a red heat for some hours together. The heat disengages the carbon dioxide, leaving only a combination of calcium and oxygen, which is common lime.

The mixture of ground lime and c.o.ke is put into a crucible that surrounds the arc of an electric light of enormous dimensions; the carbon conductors amounting to an area of one square foot or more. In order to cause the carbon to unite with the calcium a very intense heat is required, such a heat as can be obtained only in the arc of an electric light. When the enormous current is turned on (amounting to over 3000 horse-power) the mixture is melted, and after an exposure to this intense heat for a given length of time the oxygen of the unslacked lime is thrown off and the carbon unites with the calcium, which remains in the proportions of one atom of calcium to two of carbon, as before stated. This, it will be noted, is purely a heat process, and an intense one at that. No electrolytic action being required, the alternating current is used without transformation to the direct current, as is necessary in the manufacture of bleaching-powder and aluminum, both of which are electrolytic processes.

When the operation is completed the current is turned off and the compound allowed to cool. In cooling it a.s.sumes a slate color, which is slightly iridescent when exposed to light. It also crystallizes to a certain extent.

The value of this new product consists in its ability to evolve Acetylene gas in large quant.i.ties. A molecule of acetylene gas is composed of two atoms of carbon to two of hydrogen. To evolve the gas it is necessary only to pour water upon the calcium carbide, when a union takes place between the carbon of the carbide and the hydrogen of the water in the proportions above stated. If there is water enough the whole of the carbon will pa.s.s off with the gas, leaving a residuum of slacked lime.

The value of acetylene gas lies in its very intense illuminating power.

This is due to the fact that the gas is very rich in carbon as compared with other illuminating gases. It burns with a pure white light when properly mixed with air or oxygen, but if there is a lack of air it burns with a smoky flame. In this case the carbon is not all consumed and escapes into the air in the form of soot or smoke, but when burned with the proper mixture of oxygen or common air it becomes one of the most brilliant of illuminants. Acetylene, like most other gases, becomes explosive when mixed with air in certain proportions. Whether it is more dangerous to handle than ordinary illuminating gases the writer is not prepared to say, as he has not had the opportunity to make a thorough comparison between it and other gases from an experimental standpoint.

Experiment, after all, is the only sure road to absolute knowledge.

Theories are beautiful in books and lectures, but they often fail in the laboratory.

Acetylene is now being introduced as an illuminating gas for domestic and other purposes. Several methods of handling it have been proposed.

One is to condense it into strong metal cylinders and deliver it in that form; another is to erect generators at convenient places and generate the gas as it is used. A very ingenious contrivance has been invented for regulating the generation of the gas. A certain amount of the calcium carbide is placed in a gas-tight vessel containing water. As soon as the water comes in contact with the carbide the evolution of the gas begins. When the pressure on the inside of the vessel has reached a certain degree it is made, through mechanical contrivances, to lift the carbide out of the water and thus stop the evolution of the gas. When the pressure is relieved through the consumption of the gas at the burners it allows the carbide to drop into the water, when the evolution of the gas begins again.

Of course there is the same objection to this mode of lighting that attends all open burners; it is constantly discharging into the air the products of combustion, chiefly carbon dioxide, which is poisonous to animal life. As has been explained in some of the chapters on heat, in Volume II, the illuminating property of any gas is determined by the number of carbon particles that are contained in it, which become heated to incandescence as soon as they come in contact with the oxygen of the air, and remain so, for a brief period, during their pa.s.sage between the two extremes of the flame. While acetylene equals electricity in its illuminating properties, the latter still stands without a rival when considered from a sanitary standpoint, as the use of electricity does not in any degree vitiate the air in a room where it is used.

We have now given somewhat in detail the following processes that are carried on at Niagara Falls through the agency of electricity, viz.: The reduction of aluminum from its oxide alumina; the production of the new and useful compound called carborundum; the formation of calcium carbide used for the production of acetylene gas, and a large chemical works, where bleaching-powder is made. In addition to these works, there is an establishment for the production of sodium from caustic potash, which is one of the products arising from the decomposition of salt in the bleaching-powder works. There is also another establishment for the production of phosphorus made from the bones and sh.e.l.ls obtained from the phosphate beds that abound in some of the southern states, on the coast of the Atlantic Ocean. There is in process of construction a plant for the purpose of manufacturing chlorate of potash by an electrical process. In addition to these establishments mentioned, the electricity is furnished for power purposes to the Niagara Electric Light Company; to the electric railway between Niagara and Buffalo; to the Niagara Falls Railway, on the opposite side of the river; to the Niagara Power and Conduit Company of Buffalo, and the Niagara Development Company.

This is only a small beginning of the uses to which electricity will be put as an agent for the development of heat, light and power as well as for the production of all substances where electrolysis is the chief factor. Sixteen companies or more are now using electricity from the Niagara power-house,--the whole amounting to about 35,000 horse-power.

CHAPTER XXIX.

THE NEW ERA.

When we consider the number of new products for whose existence we are indebted to electricity, and the number of old products that have heretofore existed experimentally, in the laboratory of the chemist only, that have now been brought into play as useful agents in the various arts and industries, we begin to realize that this is truly an electrical age and the dawning of a new era. How many, many things there are, familiar to the children of to-day, that were not even imagined by the children of twenty-five to fifty years ago. Fifty years ago the only useful purpose to which electricity was put was that of transmitting news from city to city by the Morse telegraphic code. It will be fifty-seven years the first of April, 1901, since the first telegraph-line was thrown open to the public. Less than thirty years ago but little advance had been made in the use of electrical appliances beyond the perfection of certain private-line instruments, and a means for multiple transmission. About twenty years ago there were evidences of the beginning of a new era in electrical development. At no time in the history of the world has wonder succeeded wonder with such rapidity, producing such astounding results that have revolutionized all our modes of doing business and all of the operations of commercial and domestic life, as during the last two decades. We set our watches by time furnished by electricity from one central point of observation. We read the tape from hour to hour, upon which is recorded the commercial pulse of the world, as it throbs in the marts of trade, by means of this same speedy messenger. We enter a street-car that is lighted and heated, and at the same time propelled by the same wonderful agent. In our homes and on our streets night is turned into day by a light that outrivals all other illuminants.

When we wish to speak to a friend who may be a mile or a thousand miles away we step to the end of a wire that comes within the walls of our dwelling and we talk to him as though face to face, and means are at hand by which we may write a letter to that same friend and deliver it to him in our own handwriting and over our own signatures, so quickly that it will appear before him in full form and completeness as soon as the last period is made at the end of the last line.

One sees, and hears, and lives more in a single day in this age of electricity and steam than he did in twelve months sixty years ago. And yet there are those who cry out against modern inventions and modern civilization, and are constantly quoting the days of their grandfathers and great-grandfathers when "life was simple" and there was "time to rest." "Why are we tormented with this thought-stimulating age?" they say. "Why are our emotions called into action by modern music and modern art? Why are we called upon to help the downtrodden and oppressed, and to help to elevate mankind to a higher level? Why cannot we be left alone in peace and quiet, to live in the easiest way?"

If this be good philosophy, then the swine, if he were a reasoning being, ought to be ranked among the greatest of philosophers--when he seeks a wallow in the suns.h.i.+ne and sleeps away his useless existence. If he is useful it is because some other being of a higher order uses him to help along his own existence. The man in these days who does not "keep up with the procession" is soon trodden under foot and some other man uses him as a stepping-stone to elevate himself.

Yet this is a selfish motive, after all. The world is now rapidly advancing in light, in knowledge, in power to use the infinite gifts that the Creator has hidden in nature; but hidden only to stimulate and reward our seeking. Every man can help in this grand progress,--if not by research and positive thought-power, at least by grateful acceptance and realization of what is gained. _Look forward!_ As Emerson puts it: "To make habitually a new estimate--that is elevation."