« PředchozíPokračovat »
ELECTRICITY DIRECT FROM COAL.
MOST interesting article on the "Direct Production of Electricity from Coal," from the able pen of Mr. G. H. Stockbridge, appeared in a recent number of the Engineering Magazine. This writer informs us that Dr. W. W. Jacques of Boston has succeeded, after several years devoted to painstaking experiments, in producing a current of electricity directly from the decomposition of carbon. Dr. Jacques is quoted, on page 661, as explaining his discovin these words :-"If oxygen, ery whether pure or diluted as in air, be caused to combine with carbon or carbonaceous materials, not directly as in the case of combustion, but through an intervening electrolyte, the potentia! energy of carbon may be converted directly into electrical energy, instead of into heat."
The common form of combination of oxygen with carbon, known to everyone, is that seen in the burning of coal or wood, and the light and heat given off during this process of burning is the sensible manifestation of the energy which resided in the unburnt fuel. This energy is simply power to do work, and work has been defined as pressure acting through space, or as pressure acting over a given distance, as when a pound weight is raised a foot high. The fuel possessed this energy before it was burned, but it existed in what is known as the potential form.
An idea of what is meant by this expression, "potential energy," may be had by examining one or two examples. The hammer of a pile-driver when lying inert upon the head of a pile has no energy, either active or potential, as far as the pile is concerned. It is true that the hammer presses upon the head of the pile by virtue of its weight, but the pile resists this pressure with equal force, and no motion of either pile or hammer takes place. The hammer is unable to do any work on the pile, because its pressure or weight is not com
petent to move it through any space, and it therefore lacks energy, in this position, with reference to the pile. Let the hammer now be drawn up to the top of the frame. It will hang there as inert as when it rested upon the supporting pile, and again, as far as the pile is concerned, without doing any work. The hammer, however, was raised against the attraction of gravity, which pulls upon it, like a stretched elastic band, seeking to bring it quickly and forcibly down to its former position. The hammer now posesses what, for want of a better term, may be called the potential energy of position with reference to the upright log below it. It is now able to do work, as is instantly seen when the detent is released. The falling hammer shoots down the slippery guides at an ever-increasing velocity, and striking the pile drives it down a foot or so. As the pile goes down under the blow, the whole of the now active or kinetic energy of the hammer is given up to the stick of timber, which in turn acts upon the earth in which it is imbedded, pushing some of it out on all sides from below the point, and overcoming the friction upon its cylindrical surface. The earth about it is moved into new positions, and this movement and friction develop heat in pile and earth which radiates off and is lost to our senses, though never destroyed.
Another form of potential energy is exhibited in an ordinary clock. It is wound up by someone who is conscious of exerting a certain amount of force in order to turn the key. After the winding is completed, the clock is expected to have stored up in it enough power to keep the hands moving over the dial, hour after hour, for a week or more. The wound-up mainspring of the clock therefore possesses potential energy. It may be called the potential energy of molecular disturbance. As the key was turned round and round in
the process of winding, each small particle, or molecule, of the steel was forced slightly out of its normal position; each either compressed or subjected to tension, but all slightly distorted or disturbed. The spring, in righting itself or getting back to its normal unwound state, will give up, with slight frictional loss, all the power which the hand of the winder had put into it. The pendulum sets free a small portion of this energy at every swing, and instead of letting the wheels spin round and the hands fly over the face for a brief interval, ticks out each minute by itself, and spreads the work of unwinding over a long series of a long series of hours.
But to return to the consideration of the carbon in its state previous to being consumed. It possesses the potential energy of chemical separation. That is to say, it is able to combine, chemically, with oxygen, and when so combining, or burning, to produce those forms of active energy which we call light and heat.
When speaking of the theory of combustion Tyndall* describes an experiment performed at one of his lectures on heat. It was the burning of a small diamond in a jar of oxygen.
The diamond, as is well known, is composed entirely of pure carbon. He heated the gem to redness, and plunged it into an atmosphere of oxygen. He says: "You are to figure the atoms of oxygen showering against this diamond on all sides. They are urged toward it by what is called chemical affinity; but this force, made clear, presents itself to the mind as pure attraction, of the same mechanical quality, if I may use the term, as gravity. Every oxygen atom, as it strikes the surface, and has its motion of translationt destroyed by its collision with the carbon, assumes the motion we call heat; and this heat is so intense, the attractions exerted at these molecular distances are so mighty,
*Heat as a Mode of Motion, by John Tyndall, LL.D., F.R.S., etc.-New York: D. Appleton and Co'y, 1880. Section 48, page 43.
+Motion of translation. (Mech.) Motion in which all the parts follow the same direction; motion without rotation. Standard Dictionary, page 1918.
that the crystal is kept white hot, and the compound, formed by the union of its atoms with those of the oxygen, flies away as carbonic-acid gas.
Chemical affinity, we are justified in saying upon the authority of the late Prof. Tyndall, is of the same mechanical quality as the attraction of gravity, which gave to the hammer of the piledriver the energy which we have just been contemplating.
An electric current is a form of energy, just as light and heat are. It may, like them, be produced by the consumption of fuel. In the Jacques' apparatus this combination of carbon and oxygen is not accompanied with smoke and flame, but it is nevertheless as truly a chemical union of these elements as that observed in the rotting of timber, or in the burning of coal. In the production of electricity directly from carbon, the potential energy residing in the carbon is made active. Up to the moment of combination with oxygen the atoms of carbon are held together as an isolated mass, and it is the rushing together of these separated elements of carbon and oxygen which develops that form of energy now so familiar to us. In this appliance, under suitable conditions of heat and position, the atoms of oxygen, obeying the laws of that almost incredibly powerful attraction called chemical affinity, moving suddenly through such infinitesimal distances, as they do, yet beat upon the mass of carbon so fiercely that we stand amazed at the enormous aggregate result. One might almost say that the destructive blows dealt by these myriad liliputian hammers break up the solid structure of the carbon and pour upon the conductors the energy of giant strokes.
As in the case of pile-driver and clock-spring, heat and motion were both produced by the transformance of potential into active energy, so in this electrical machine the production of heat is seen together with peculiar and powerful molecular movement along the wires, which is known to us as an electric current.
The consumption of carbon to pro
duce electricity is attended by phenomena similar to those observed in the more familiar examples of burning and volting. There is the production of a residuum like the ash left after fire, together with the disengagement of a certain amount of gas and heat.
The production of electricity is here effected by inserting a prism of carbon into a melted mass of caustic soda (sodium hydrate), the whole contained in an iron pot. One wire is given off from the pot and the other from the carbon prism, and on this circuit electric lamps may be placed. The iron pot is heated to a temperature of between 400 or 500 centigrade, by means of a fire of coals placed immediately below it. The caustic soda is impregnated with ordinary atmospheric air by means of an air-pump, which forces it into the molten mass through a "rose" placed beneath the carbon rod. The oxygen in the caustic soda begins combining with the carbon, and this chemical combining is rendered continuous by the presence of the air constantly pumped into it. A residuum formed in this process is carbonate of soda which, as Mr. Stockbridge tells us, "results from the union of some of the caustic soda with the carbonic-acid developed in the generating process or coming from the injected air." The ash from the consumed carbon which forms in the melted sodium hydrate increases as the operation continues, and tends to lessen the effective action of the caustic soda. Dr. Jacques has found that the addition of a small per
centage of the oxide of magnesium renders the caustic soda effective for a longer time. The reason for this is explained in the article referred to.
Putting the description of the action of the Jacques' furnace in the language of electricians, we are told :-" Briefly the process employed by Jacques consists in chemically combining oxygen with carbon by impregnating a molten basic electrolyte, which is in contact with the carbon, with oxygen or air, and collecting the electricity thereby developed by means of an electrode not acted on by the impregnated electrolyte when the circuit is completed." The molten basic electrolyte is the caustic soda. The word electrolyte means a chemical compound which can be decomposed by an electric current. The electrode is here the iron pot, which is not acted on by the melted caustic soda.
The discovery of Dr. Jacques is certainly a notable step forward in the solution of the great problem of cheapening the production of electricity. Whether or not it can be considered as introducing a probable rival of the steam-engine is still an unsettled question. At present the production of a temperature of about 450° C., or 842° F., means the burning of fuel, and the cost of operating an air-pump is also a factor in the problem. The value of the carbon, the caustic soda, and the oxide of magnesium all go to make up what is called the cost of operation of the whole apparatus, and upon that aspect of the question no reliable data has yet appeared.
Geo. S. Hodgins.
LIFE is a battle of hard facts against
theory. The battlefield of experimental democracy is strewn with disappointed hopes, aspirations cut short, and castles in the air cruelly destroyed. What hopes we in Ontario built upon the benign and beneficent influences of free education! Brought to the door of the humblest cottage, it would enter in and make the lives of the people happier and more true. Labour would become more efficient and more dignified, and before the bright light of knowledge the hideous phantoms of vice and crime would fly away. With what care have we studied the systems of other countries, and, step by step, built up and perfected a system of our own, leading by natural grades from the public school and kindergarten at the cottage door to the University of Toronto! With what pride, and natural pride, we look at the crowning point of our system, which commands the respect and admiration of the whole American Continent! And we receive with complacent satisfaction the congratulations of our visitors who attend the great educational conventions which from time to time are held in our midst.
twenty years, as was lately pointed out by Mr. Galt in The Week, the expenditure upon these two departments has been seventy-nine million dollars. The sum is enormous. The taxpayer does not grudge the money, but, in a quiet way, he has shown a certain feeling of diffidence in the wisdom of the authorities. In the year 1891 the Provincial Government passed an Act providing that County Councils may require a portion of the liability of the County to be paid by the County pupils in fees, but such fees must not exceed one dollar per month. The popularity of this concession was shown by the fact that within one year from the passing of the Act there were seventy-seven High Schools in which fees were exacted.
Why, we naturally ask, have educationists been allowed, without criticism or comment, to force upon the people a system of higher education which, it would seem, they grudgingly pay for? Why am I forced, whether I wish it or not, to be my brother's teacher? primary duty of a government is, surely, to govern. We understand that the functions of a government are extended to education because it is for the public good: 1. that no man should be brought up without an education, and so become a possible burden or menace to the State; 2. that no able man should be lost to the State from the inability of his parents to pay for his education; 3. that every man should be able to make an intelligent use of his rights of suffrage. How does the Ontario Educational System serve the public good? Experience does not seem to show that education such as we have makes people more moral. In the year 1869 the total number of commitments in the Province for various offences was 5,655; in 1889, 12,531; an increase of 6,876, as against an estimated increase in population of 611,600. Juvenile crime has increased to an alarming
It is, indeed, hard to have to admit that the Educational System, of which we hoped so much, must be ranked among the disappointments of life; that it has not decreased crime and that, instead of an angel of light, it has proved an octopus with an angel's face, reaching out its tentacles into the houses and pockets of the people, degrading our professions and depopulating the country. The language is strong; but so are the facts.
There are twelve departments in our system, and two of these alone, the Public Schools and High Schools, according to the last report of the Minister of Education in the year 1894-'95, cost the Province over fourand-a-half million dollars. In the last
extent; but we complacently, in the face of statistics which prove to the contrary, attribute this phenomenon to the importation of pauper children from Europe. At the Spring Assizes held in Hamilton this year, when the Grand Jury, in their presentment, referred to the number of serious crimes committed by youths which had come before them, and placed the blame, as usual, upon the children imported from English cities, Mr. Justice Street, the presiding judge, in his reply, pointed out that the young men convicted were all brought up, with one exception, in the Public Schools of that city, where, he said, "they were simply taught reading, writing, arithmetic and a smattering of other things, but they were not taught the difference between right and wrong."
One of the most fruitful sources of crime, as was pointed out by Mr. Rutherford Hayes, ex-President of the United States, at Cincinnati, in 1890, is "the inordinate eagerness to acquire wealth and to get money sufficient to satisfy the desires of the extravagant or the profligate, which is so prevalent in these days," and this desire is undoubtedly fostered by the spread of free education. Which, we may ask, is the greater menace to the State, the educated man or the ignoramus out of work? Surely the man most capable of mischief. Yet we in Ontario burden ourselves with a heavy tax to turn out every year a crop of men for whom there is no legitimate occupation for which they are adapted. In the city of Toronto it is estimated that there are 200 lawyers unable to pay their office rent! Indeed, in every town in Ontario there are, at least, onethird too many lawyers, and these men are not only a loss to the State of so many taken from the ranks of the producers, but they constitute a distinct menace to the community. Nine men out of ten, when pushed to the wall, will depart from the lines of strict propriety and honour; and to the overcrowding of the legal profession in Ontario must be attributed the degradation of that calling from a profession to
the level of a trade. Men are driven by the increasing competition and the difficulty of obtaining a livelihood to have recourse to methods of making money, which, fifteen years ago, would not have been tolerated: taxing for work, "working" the churches, blackmail and the manufacture of litigation; a fact which no one familiar with the practical working of the law, who keeps his eye on the current law reports, can fail to recognize. And so it goes on all down the line. The surplus doctors are just as numerous as the surplus lawyers. And if you advertise for a public school teacher at the lowest possible living wage, you will have a hundred and fifty "qualified" applicants.
In twenty years we have educated millions of pupils, and we can not point to one man, who could not have paid for his own education, whose place could not be filled at once by a hundred ; not one man, to whose education we feel glad that we have subscribed. While in the general condition of the people we see no great improvement to console us for the money we have spent.
Perhaps this may be due to the fact that our present system more than anything else tends to drive our best men from the country. The difficulties of the educated man only begin when his education is completed. Where the field is as overcrowded as it is in Ontario, there must inevitably be a period of unremunerative waiting. If a man cannot afford to pay for his education, he cannot afford to support himself during this time.
He finds that in the larger centres of the United States the prizes and opportunities are more attractive and the cost of waiting is no greater; and to-day it is the cities of the United States that are reaping the benefit of millions spent by the Ontario taxpayer in higher education.
This statement is borne out by statistics. Taking the years from 1889 to 1894, inclusive, it is estimated that in the former year there were 2,300 doctors and about 1,400 lawyers prac