Chapter 8

The meaning of this geological distribution of the fuels is entirely fortuitous. Dr. M'Gee tells us that as their formation depended on local conditions (such as plant growth), and as we have no means of judging why such local conditions occurred within any given area, so must we regard the existence of fuel products in particular regions as beyond explanation. Of one point, however, we are well assured, namely that the volume of the fuels of the future is developed in an inverse proportion to their geological age. The proportionate volume, as it has been expressed, diminishes progressively as the geological scale is descended. Again, the weight of the fuels varies directly with their age; for it is in the older formation of any series that we come upon the oils and tars and asphaltum, while the marsh gas exists in later and more recently formed deposits. Further geological research shows us that the American gas fields exist each as an inverted trough or dome, a conformation due, of course, to the bending and twisting of the rocks by the great underground heat forces of the world. The porous part of the dome may be sandstone or limestone, and above this portion lie shales, which are the opposite of porous in texture. The dome, further, contains gas above, naphtha in the middle, and petroleum below, while last of all comes water, which is usually very salt. In the Indiana field, however, we are told that the oils lie near the springing or foundation of the arch of the dome, and at its crown gas exists, and overlies brine.

A very important inquiry, in relation to the statement that upon the products whose composition and history have just been described the fuel supply of the future will depend, consists in the question of the extent and duration of these natural gas and oil reservoirs. If we are beginning to look forward to a time when our coal supply will have been worked out, it behooves us to ask whether or not the supply of natural gas and oil is practically illimitable. The geologist will be able to give the coming man some degree of comfort on this point, by informing him that there seems to be no limit to the formation of the fuel of the future.

Natural gas is being manufactured to-day by nature on a big scale. Wherever plant material has been entombed in the rock formations, and wherever its decomposition proceeds, as proceed it must, there natural gas is being made. So that with the prospect of coal becoming as rare as the dodo itself, the world, we are told by scientists, may still regard with complacency the failure of our ordinary carbon supply. The natural gases and oils of the world will provide the human race with combustible material for untold ages--such at least is the opinion of those who are best informed on the subject. For one thing, we are reminded that gas is found to be the most convenient and most economical of fuels. Rock gas is being utilized abroad even now in manufacturing processes. Dr. M'Gee says that even if the natural supply of rock gas were exhausted to-morrow, manufacturers of glass, certain grades of iron, and other products would substitute an artificial gas for the natural product rather than return to coal. He adds that "enormous waste would thereby be prevented, the gas by which the air of whole counties in coke-burning regions is contaminated would be utilized, and the carbon of the dense smoke clouds by which manufacturing cities are overshadowed would be turned to good account." So that, as regards the latter point, even Mr. Ruskin with his horror of the black smoke of to-day and of the disfigurement of sky and air might become a warm ally of the fuel of the future. The chemist in his laudation of rock gas and allied products is only re-echoing, when all is said and done, the modern eulogy pronounced on ordinary coal gas as a cooking and heating medium.

We are within the mark when we say that the past five years alone have witnessed a wonderful extension in the use of gas in the kitchen and elsewhere. It would be singular, indeed, if we should happen to be already anticipating the fuel of the future by such a practice. Whether or not this is the case, it is at least satisfactory for mankind to know that the mother earth will not fail him when he comes to demand a substitute for coal. I may be too early even to think of the day of extinction; but we may regard that evil day with complacency in face of the stores of fuel husbanded for us within the rock foundations of our planet.--_Glasgow Herald._

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PORTABLE ELECTRIC LIGHT.

The famous house of MM. Sautter, Lemonnier & Co. takes a conspicuous part in the Paris exhibition, and from the wide range of its specialties exhibits largely in three important branches of industry: mechanics, electricity, and the optics of lighthouses and projectors. In these three branches MM. Sautter, Lemonnier & Co. occupy a leading position in all parts of the world.

The invention of the aplanetic projector, due to Col. Mangin, was a clever means of overcoming difficulties, practically insurmountable, that were inseparable from the construction of parabolic mirrors; this contributed chiefly to the success of MM. Sautter, Lemonnier & Co. in this direction. The firm has produced more than 1,500 of these apparatus, representing a value of nearly £500,000, for the French and other governments.

Besides the great projector, which forms the central and crowning object of the exhibit of MM. Sautter, Lemonnier & Co. in the machinery hall, the firm exhibits a projector 90 centimeters in diameter mounted on a crane traveling on wheels, in the pavilion of the War Department. The lamp used for this apparatus has a luminous value of 6,000 carcels, with a current of 100 amperes; the amplifying power of the mirror is 2,025, which gives an intensity of ten millions to twelve millions of carcels to the beam.

Projectors used for field work are mounted on a portable carriage, which also contains the electric generator and the motor driving it.

It consists of a tubular boiler (Dion, Bouton & Trepardoux system). This generator is easily taken to pieces, cleaned, and repaired, and steam can be raised to working pressure in 20 minutes. The mechanical and electrical part of the apparatus consists of a Parsons turbo-motor, of which MM. Sautter, Lemonnier & Co. possess the license in France for application to military and naval purposes. The speed of the motor is 9,000 revolutions per minute, and the dynamo is driven direct from it; at this speed it gives a current of 100 amperes with and from 55 to 70 volts; the intensity of the light is from 5,500 to 6,000 carcels. The carriage upon which the whole of this apparatus is mounted is carried on four wheels, made of wood with gun metal mountings. These are more easy to repair when in service than if they were wholly of iron. The weight of the carriage is three tons.--_Engineering._

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ELECTRIC MOTOR FOR ALTERNATING CURRENTS.

Prof. Galileo Ferraris, of Turin, who has carefully studied alternating currents and secondary transformers, has constructed a little motor based upon an entirely new principle, which is as follows: If we take two inductive fields developed by two bobbins, the axes of which cut each other at right angles, and a pole placed at the vertex of the angle, this pole will be subjected to the simultaneous action of the two bobbins, and the resultant of the magnetic actions will be represented in magnitude and direction by the diagonal of the parallelogram, two consecutive sides of which have for their length the intensity of the two fields, and for their direction the axes of the two bobbins.

If into each of these bobbins we send alternating currents having between one bobbin and the other a difference of phase of 90°, the extremity of the resultant will describe a circle having for its center the vertex of the right angle.

If, instead of a fixed pole, we use a metal cylinder movable on its axis, we shall obtain a continuous rotatory motion of this part, and the direction of the movement will change when we interchange the difference of phase in the exciting currents. This rotatory movement is not due to the Foucault currents, for the metal cylinder may consist of plates of iron insulated from each other.

In order to realize the production of these fields, several means can be employed: The current is sent from an alternating current machine into the primary circuit of a transformer and thence into one of the bobbins, the other being supplied by means of the secondary current of the transformer. A resistance introduced into the circuit will produce the required difference of phase, and the equality of the intensities of the fields will be obtained by multiplying the number of turns of the secondary wire on the bobbin. Moreover, the two bobbins may be supplied by the secondary current of a transformer by producing the difference of phase, as in the first case.

In the motor constructed by Prof. Ferraris the armature consisted of a copper cylinder measuring 7 centimeters in diameter and 15 centimeters in length, movable on its axis. The inductors were formed of two groups of two bobbins. The bobbins which branched off from the primary circuit of a Gaulard transformer, and were connected in series, comprised 196 spirals with a resistance of 13 ohms; the bobbins comprising the secondary circuit were coupled in parallel, and had 504 spirals with 3.43 ohms resistance. In order to produce the difference of phase, a resistance of 17 ohms was introduced into the second circuit, when the dynamo produced a current of 9 amperes with 80 inversions per second. Under these conditions the available work measured on the axis of the motor was found for different speeds: Revolutions per minute: 262--400--546--650--722--770. Watts measured at the brake: 1.32--2.12--2.55--2.77--2.55--2.40. The maximum rendering corresponds to a speed of rotation of 650 revolutions, and Prof. Ferraris attributes the loss of work for higher speeds to the vibrations to which the machine is exposed. At present the apparatus is but a laboratory one.--_Bulletin International de l'Electricite._

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THE ELECTRIC AGE.

By CHARLES CARLETON COFFIN.

The application of electricity for our convenience and comfort is one of the marvels of the age. Never in the history of the world has there been so rapid a development of an occult science. Prior to 1819 very little was known in regard to magnetism and electricity. During that year Oersted discovered that an electric current would deflect a magnetic needle, thus showing that there was some relationship between electric and magnetic force. A few months later, Arago and Sir Humphry Davy, independently of each other, discovered that by coiling a wire around a piece of iron, and passing an electric current through it, the iron would possess for the time being all the properties of a magnet. In 1825 William Sturgeon, of London, bent a piece of wire in the form of the letter U, wound a second wire around it, and, upon connecting it with a galvanic battery, discovered that the first wire became magnetic, but lost its magnetic property the moment the battery was disconnected. The idea of a telegraphic signal came to him, but the electric impulse, through his rude apparatus, faded out at a distance of fifty feet. In 1830 Prof. Joseph Henry, of this country, constructed a line of wire, one and a half miles in length, and sent a current of electricity through it, ringing a bell at the farther end. The following year Professor Faraday discovered magnetic induction. This, in brief, is the genesis of magnetic electricity, which is the basis of all that has been accomplished in electrical science.

The first advance after these discoveries was in the development of the electric telegraph--the discovery in 1837, by the philosopher Steinhill, that the earth could serve as a conductor, thus requiring but one wire in the employment of an electric current. Simultaneously came Morse's invention of the mechanism for the telegraph in 1844, foreshadowed by Henry in the ringing of bells, thus transmitting intelligence by sound. Four years later, in 1848, Prof. M. G. Farmer, still living in Eliot, Me., attached an electro-magnet to clockwork for the striking of bells to give an alarm of fire. The same idea came to William F. Channing. The mechanism, constructed simply to illustrate the idea by Professor Farmer, was placed upon the roof of the Court House in Boston, and connected with the telegraph wire leading to New York, and an alarm rung by the operator in that city. The application of electricity for giving definite information to firemen was first made in Boston, and it was my privilege to give the first alarm on the afternoon of April 12, 1852.

At the close of the last century, Benjamin Thompson, born in Woburn, Mass., known to the world as Count Rumford, was in the workshop of the military arsenal of the King of Bavaria in Munich, superintending the boring of a cannon. The machinery was worked by two horses. He was surprised at the amount of heat which was generated, for when he threw the borings into a tumbler filled with cold water, it was set to boiling, greatly to the astonishment of the workmen. Whence came the heat? What was heat? The old philosopher said that it was an element. By experiment he discovered that a horse working two hours and twenty minutes with the boring machinery would heat nineteen pounds of water to the boiling point. He traced the heat to the horse, but with all his acumen he did not go on with the induction to the hay and oats, to the earth, the sunshine and rain, and so get back to the sun. One hundred years ago there was no chemical science worthy of the name, no knowledge of the constitution of plants or the properties of light and heat. The old philosophers considered light and heat to be fluids, which passed out of substances when they were too full. Count Rumford showed that motion was convertible into heat, but did not trace the motion to its source, so far as we know, in the sun.

It is only forty-six years since Professor Joule first demonstrated the mutual relations of all the manifestations of nature's energy. Thirty-nine years only have passed since he announced the great law of the convertibility of force. He constructed a miniature churn which held one pound of water, and connected the revolving paddle of the churn with a wheel moved by a pound weight, wound up the weight, and set the paddle in motion. A thermometer detected the change of temperature and a graduated scale marked the distance traversed by the descending weight. Repeated experiments showed that a pound weight falling 772 feet would raise the temperature of water one degree, and that this was an unvarying law. This was transferring gravitation to heat, and the law held good when applied to electricity, magnetism, and chemical affinity, leading to the conclusion that they were severally manifestations of one universal power.--_Congregationalist._

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EARLY ELECTRIC LIGHTING.

The opening of the new station of the Electric Lighting Co., of Salem, Mass., was recently celebrated with appropriate festivities.

Among the letters of regret from those unable to attend the opening was the following from Prof. Moses G. Farmer:

"ELIOT, Me., Aug. 5, 1889.

"_To the Salem Electric Lighting Company, Charles H. Price, President_:

"GENTLEMEN: It would give me great pleasure to accept your kind invitation to be present at the opening of your new station in Salem on the 8th of this present August.

"It is now thirty years since the first dwelling house in Salem was lighted by electricity. That little obscure dwelling, 11 Pearl Street, formerly owned by 'Pa' Webb, had the honor to be illuminated by the effulgent electric beam during every evening of July, 1859, as some of your honored residents, perhaps, well remember. Mr. George D. Phippen can doubtless testify to one or more evenings; Mr. Wm. H. Mendell, of Boston, can also add his testimony; dozens of others could also do the same, had not some of them already passed to the 'great beyond,' among whom I well recollect the interest taken by the late and honored Henry L. Williams, Mr. J. G. Felt, and I do not know how many others. I well remember reading some of the very finest print standing with my back to the front wall and reading by the light of a 32 candle power lamp on the northernmost end of the mantel piece in the parlor; very possibly the hole in which the lamp was fastened remains to this day. In a little closet in the rear sleeping room was a switch which could be turned in one direction and give a beautiful glow light, while if turned in the other direction, it instantly gave as beautiful a dark. My then 12 year old daughter used to surprise and please her visitors by suddenly turning on and off the 'glim.' It is not well to despise the day of small things, for although the dynamo had not at that date put in an appearance, and though I used thirty-six Smee cells of six gallons capacity each, yet I demonstrated then and there that the incandescent electric light was a possibility, and although I innocently remarked to the late Samuel W. Bates, of Boston, who with his partner, Mr. Chauncey Smith, furnished so generously in the interest of science, not wholly without hope of return, the funds for the experiment, that it 'did not take much zinc,' and though Mr. Bates as naively replied, 'I notice that it takes some silver, though,' still it was then and there heralded as the coming grand illuminant for the dwelling. I am thankful to have lived to see my predictions partly fulfilled.

"During the early fifties I published a statement something like this: 'One pound of coal will furnish gas enough to maintain a candle light for fifteen hours. One pound of gas (the product of five pounds of coal) will, in a good fishtail gas burner, furnish one candle light for seventy-five hours. One pound of coal burned in a good furnace, under a good boiler, driving a good steam engine, turning a good magneto-electric machine, will give a candle light for one thousand hours. But if all the energy locked up in one pound of pure carbon could be wholly converted into light, it would maintain one candle light for more than one and a half years.'

"So, gentlemen, _nil desperandum_; there is still room for improvement. Let your motto be 'Excelsior.' Possibly you may have already extracted from one-fifteenth to one-twelfth of the energy stored in the pound of carbon, but hardly more. Go on, go on, and bring it so cheap as to reach the humblest dwelling when you shall celebrate the centennial of the opening of your new station.

"I do most sincerely regret that I cannot be with you in the flesh. I am, like Ixion of old, confined to a wheel (chair in my case), cannot walk, cannot even stand; hence, owing to the impairment of my understanding (???), I must wish you all the enjoyments of the evening, and gladly content myself that you have made so much possible.

"Very truly yours, MOSES G. FARMER."

* * * * *

THE MODERN THEORY OF LIGHT.[1]

[Footnote 1: Being the general substance of a lecture to the Ashmolean Society in the University of Oxford, on Monday, June 3, 1889. [Reprinted from the _Liverpool University College Magazine_.]]

By Prof. OLIVER LODGE.

To persons occupied in other branches of learning, and not directly engaged in the study of physical science, some rumor must probably have traveled of the stir and activity manifest at the present time among the votaries of that department of knowledge.

It may serve a useful purpose if I try and explain to outsiders what this stir is mainly about, and why it exists. There is a proximate and there is an ultimate cause. The proximate cause is certain experiments exhibiting in a marked and easily recognizable way the already theoretically predicted connection between electricity and light. The ultimate cause is that we begin to feel inklings and foretastes of theories, wider than that of gravitation, more fundamental than any theories which have yet been advanced; theories which if successfully worked out will carry the banner of physical science far into the dark continent of metaphysics, and will illuminate with a clear philosophy much that is at present only dimly guessed. More explicitly, we begin to perceive chinks of insight into the natures of electricity, of ether, of elasticity, and even of matter itself. We begin to have a kinetic theory of the physical universe.

We are living, not in a Newtonian, but at the beginning of a perhaps still greater Thomsonian era. Greater, not because any one man is probably greater than Newton,[2] but because of the stupendousness of the problems now waiting to be solved. There are a dozen men of great magnitude, either now living or but recently deceased, to whom what we now know toward these generalizations is in some measure due, and the epoch of complete development may hardly be seen by those now alive. It is proverbially rash to attempt prediction, but it seems to me that it may well take a period of fifty years for these great strides to be fully accomplished. If it does, and if progress goes on at anything like its present rate, the aspect of physical science bequeathed to the latter half of the twentieth century will indeed excite admiration, and when the populace are sufficiently educated to appreciate it, will form a worthy theme for poetry, for oratorios, and for great works of art.

[Footnote 2: Though, indeed, a century hence it may be premature to offer an opinion on such a point.]

To attempt to give any idea of the drift of progress in all the directions which I have hastily mentioned, to attempt to explain the beginnings of the theories of elasticity and of matter, would take too long, and might only result in confusion. I will limit myself chiefly to giving some notion of what we have gained in knowledge concerning electricity, ether, and light. Even that is far too much. I find I must confine myself principally to light, and only treat of the others as incidental to that.

For now well nigh a century we have had a wave theory of light; and a wave theory of light is quite certainly true. It is directly demonstrable that light consists of waves of some kind or other, and that these waves travel at a certain well-known velocity, seven times the circumference of the earth per second, taking eight minutes on the journey from the sun to the earth. This propagation in time of an undulatory disturbance necessarily involves a medium. If waves setting out from the sun exist in space eight minutes before striking our eyes, there must necessarily be in space some medium in which they exist and which conveys them. Waves we cannot have unless they be waves in something.

No ordinary medium is competent to transmit waves at anything like the speed of light; hence the luminiferous medium must be a special kind of substance, and it is called the ether. The _luminiferous_ ether it used to be called, because the conveyance of light was all it was then known to be capable of; but now that it is known to do a variety of other things also, the qualifying adjective may be dropped.

Wave motion in ether, light certainly is; but what does one mean by the term wave? The popular notion is, I suppose, of something heaving up and down, or, perhaps, of something breaking on the shore in which it is possible to bathe. But if you ask a mathematician what he means by a wave, he will probably reply that the simplest wave is

y = a sin (p t - n x),

and he might possibly refuse to give any other answer.