USA > Maine > York County > Parsonsfield > A history of the first century of the town of Parsonsfield, Maine > Part 11
Note: The text from this book was generated using artificial intelligence so there may be some errors. The full pages can be found on Archive.org (link on the Part 1 page).
Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7 | Part 8 | Part 9 | Part 10 | Part 11 | Part 12 | Part 13 | Part 14 | Part 15 | Part 16 | Part 17 | Part 18 | Part 19 | Part 20 | Part 21 | Part 22 | Part 23 | Part 24 | Part 25 | Part 26 | Part 27 | Part 28 | Part 29 | Part 30 | Part 31 | Part 32 | Part 33 | Part 34 | Part 35 | Part 36 | Part 37 | Part 38 | Part 39 | Part 40 | Part 41 | Part 42 | Part 43 | Part 44 | Part 45 | Part 46 | Part 47 | Part 48 | Part 49 | Part 50
86
HISTORY OF PARSONSFIELD.
supposed, however, that this is the velocity of electricity under all conditions.
Such an extraordinary speed, it was early seen fits this agent for the rapid transmission of signals over long distances. The first proposal of this kind was by a writer now known only by his initials, C. M. His plan is to have as many wires as there are letters, so arranged at the sending station, that the extrem- ities of the wires can be brought, each at pleasure, in contact with a charged body, say the prime conductor of an electrical machine. At the receiving station each wire terminates in a small ball placed just above a light movable letter, corresponding with one at the sending station. When a message is to be sent and received, it is only necessary for the sender to bring the wires, bear- ing the proper letters to spell his message, in contact with the charged con- ductor, while the receiver has simply to note what letters are attracted to the balls and the order of succession. An apparatus on this plan but employing small pith balls whose repulsion should indicate the letters intended, was constructed in 1774, by Lesage. The next step was to reduce the number of wires to a single one and employ the different degrees of divergence which might be produced by properly regulated amounts of charge admitted to the wire, to indicate the different letters intended. This was proposed in 1787, by Lomond, but of course it was not satisfactory. In 1798, the king of Spain had in opera- tion a fairly successful telegraph, and various endeavors were made by different persons elsewhere to solve the problem of electrical transmission of intelligence before the use of electro-magnetism for that purpose.
It should be borne in mind that the science of chemistry, as we know it, had almost no existence in the time of these early electrical experiments, and it there- fore happened that little note was made of the chemical changes which often attended them. The peculiar odor which attends the action of the electrical machine, and which we now know is due to the formation of ozone, was of course noticed but was not ascribed to its true cause. Priestly attributed some of the discolorations of metals under the action of the spark, to the action of "phlo- giston." This, translated into the language of modern chemistry, would be equiv- alent to oxidation. Cavendish, in 1781, explained the diminution which a given amount of air experiences, under the continued discharge of powerful sparks, to the formation of nitric acid. In 1789, water was decomposed, and its constituent gases were again combined to reform water. This experiment was decisive of the old contest concerning the phlogiston theory, which long held its place in chemistry.
The year 1789 was one of the most memorable in the history of physical science. It was then that the attention of Galvani was attracted by the convul- sions excited in the legs of a prepared frog lying near an electrical machine in operation. He at once commenced a careful study of the conditions under which the convulsions took place, and was led to inquire if they could be produced by atmospheric electricity. He was watching to see if any effect was produced while some frog preparations were hanging by iron hooks attached to an iron
87
HISTORY OF PARSONSFIELD.
railing and he noticed that when a metallic connection was made between the crural nerve and the muscles of the leg, the convulsions occurred, and he finally concluded that he had found a new source of electricity,-the so-called " animal electricity." The greatest interest was aroused and Volta, with untiring zeal entered on the work of investigation. At first, he was inclined to the view of Galvani, but he was soon led to believe that the electrical disturbance noticed had its origin in the contact of the metals employed,-or more generally, in the contact of heterogeneous substances. The peculiar taste which is excited, when two different metals are placed in contact with the tongue and with each other, was known to Volta; and he employed this as a means of classifying the metals, or arranging them in a series according to their relative power of producing elec- tricity by contact. Afterwards he employed the condenser electroscope and established the series more accurately, which is now known as " Volta's series." He also showed that no closed circuit composed of metals only can, on the whole, cause an electric disturbance, but that it is necessary that there should be at least one moist conductor, or a conductor of the " second class " included in the series. Robison, in 1792, endeavored to exaggerate the effect of a single pair of metals by piling up several pieces of silver and zinc in alternate order, and as it would seem with some success. But it was Volta who at the close of the year 1799, made the first effective arrangement. This he described in a letter to Sir Joseph Banks, then President of the Royal Society in London, in 1800. The letter con- tained a description of the now well known "voltaic pile " and of the " crown of cups." The latter we now know as the voltaic battery.
A bitter controversy arose between the partisans of Galvani and those of Volta. Even the great Humboldt took the side of Galvani and advocated in written works, the view which Galvani proposed. It is clear, however, that this view had to be abandoned after the invention of the voltaic battery. Volta, in 1801, communicated his views and showed his experiments to the National In- stitute of France; and a commission was appointed to report on them. Sir Humphrey Davy showed that a current of electricity can be produced by the ac- tion of two liquids and one metal. Nobili did the same thing for three liquids without the use of any metal. Combinations of two metals and two liquids soon followed, which finally resulted in the so-called constant batteries of Daniell, Grove and others.
The phenomena presented by a single voltaic element or cell are by no means striking to the superficial observer. Simple and inexpensive as this apparatus is, however, it has proved by far a more important invention than any which had preceded it. We will, therefore, notice a few of the important results which im- mediately followed after it became known. A few facts had been noticed, before the invention of Volta, which could only be referred to chemical action. Thus, Fabbroni observed that tin and mercury when in contact with other metals be- come rapidly oxidized which otherwise is not the case. Humboldt noted, in
88
HISTORY OF PARSONSFIELD.
1795, the appearance of bubbles of hydrogen on a silver plate which formed one of the metals of a combination used to excite electricity, and he ascribed this to the decomposition of water, though this was with him a mere hypothesis. Car- lisle and Nicholson, immediately on the arrival of Volta's letter in London, effected the decomposition of water in a way which left no doubt concerning it; and Robertson proposed to employ the gases liberated as a measure of the cur- rent. Cruikshank extended this study to solutions of the metallic salts and thus laid the foundation of the galvanoplastic method of covering conducting bodies with metals, as in gold and silver plating. These researches were taken up by Sir Humphrey Davy, and by the use of powerful batteries, they resulted in the de- composition of the alkalies and the alkaline earths. In 1852, Bunsen produced aluminium, the metallic basis of common clay.
Not only were these triumphs achieved in chemistry, by the use of the battery, but the more obvious laws as respects the behavior of the electric current were deduced, and thus was laid the foundations of the electro-chemical theory of chemical combinations which was elaborated by Berzelius. Not to dwell on the details of this now supplanted theory, it may be remarked that it served a very useful purpose in chemistry in bringing facts into order and in stimulating re- rearch.
In 1834, Faraday established an exact nomenclature by means of which he could clearly describe whatever results research might enable him to reach, and then there followed a long series of beautiful discoveries in the course of which Faraday may almost be said to have created the modern science of electricity. He showed that the absolute amount of an elementary substance set free from its combination depends only on the amount of electricity which passes through the electrolytic compound. He also showed that the amounts of the different chemi- cal elements which can be set free from their combinations by the same amount of electricity are always in the proportions of their combining weights, respect- ively. This being so, it was easy to employ some of the metallic solutions as means of measuring the strength of the electrical current. It is only necessary to pass the current through a metallic solution, for a given time, and to ascertain by weighing, the gain in weight of the negative electrode (the metal by which the current leaves the solution). Knowing the chemical equivalent of the metal thus deposited, in a unit of time, in any given case, the strength of the current is known in terms of some definite quantity of the same metal assumed as a standard. The standard quantity may be arbitrary or, better, it may be related to some other easily observed phenomena, such as the heat evolved, or the deflec- tion of a magnetic needle.
Our space will not permit even the mention of the labors of others with respect to this important matter, and it must be left with the remark that the researches of Faraday must be looked upon as marking an epoch in the history of electrical science, equally important for theory and for the practical results which have
89
HISTORY OF PARSONSFIELD.
followed. An observation of Schoenbein, in 1840, must here be mentioned. The peculiar odor which is perceived in the neighborhood of a stroke of lightning had early been noticed in the vicinity of an electrical machine in good operation. Schoenbein discovered the same thing in connection with the galvanic battery and careful inquiry resulted in referring it to the formation of a peculiar combi- nation of oxygen with itself so that a molecule consists of three atoms instead of two as is ordinarily the case.
In 1802, Gautherot observed that two plates of the same metal, for example platinum or gold, which have formed part of a voltaic circuit by dipping in acidulated water, give rise, when placed on the tongue, to the peculiar taste which is perceived when two dissimilar metals are so placed. Ritter put together a num- ber of such plates, with moistened conducting materials between them, after the fashion of Volta's pile. When the extreme plates were connected with the con- ducting wires of an active voltaic battery, for some minutes, and then the wires were disjoined from the battery, it was found that the pile so treated could be used as a battery. Ritter regarded this arrangement as analogous with a con- denser. Volta, on the other hand, referred the effects produced to chemical changes which had been effected by the battery current. Marianini, in 1815, reinvestigated the matter and found that the pile was active even after replacing the moist conductors with others, and after drying the plates. He referred the results to the altered electrical properties of the metals. Subsequently, Grove, using two strips of platinum, one of which was surrounded by hydrogen gas and the other by oxygen made his well-known gas battery. The action, in general, to which these results are due, is called polarization and is at the basis of all the modern so-called secondary, or storage, batteries. The whole matter has been most carefully investigated by Plante, and has been utilized by him and by others in the construction of batteries for the so-called storing of electricity for com- mercial purposes. It will be seen, however, that what is really done is to effect certain chemical changes in the secondary battery whereby products are set free which can subsequently reunite and so produce an amount of current represent- ing the original current which set them free.
The various forms of batteries, both primary and secondary, which have from time to time appeared must be passed over without special mention, since in many of them there is nothing which marks progress. It will be important, how- ever, to remark that the polarization just spoken of, and which takes place to some extent in all simple primary batteries is injurious in character, in that it sets up a counter electromotive force which diminishes the current which other- wise would be produced, thereby rendering the batteries inconstant in their action. This difficulty has been obviated in various ways, notably by Daniell, Grove and Bunsen. The plan by which they all accomplish this object is to employ two liquids and two metals in the construction of the battery. The two liquids are not allowed to freely mingle, but are separated by a membrane or a porous porce-
90
HISTORY OF PARSONSFIELD.
lain cell. The liquids are of such character that they do not permit any chemical product to be formed which can set up the counter electromotive force above spoken of. Daniell employed solutions of sulphate of copper and sulphate of zinc, and the metals copper and zinc. The battery thus formed is remarkably constant and long continued in its action.
The long and bitter contests which have been carried on concerning the source of the electromotive force of the galvanic cell, must be passed over with the sim- ple remark that, now since the establishment of the principle of the " conserva- tion of energy," it must be agreed by all parties that the current is maintained by the chemical actions which go on in the battery, whatever part the contacts of the different elements entering into the composition of the battery may play.
We now come to a most interesting epoch, namely, that in which the relations between electricity and magnetism were discovered. The principal discovery was made in 1820, by Oersted, in Copenhagen. Oersted found that when a wire joining the poles of an active galvanic battery is brought into the neighborhood of freely suspended magnet and parallel with it, the magnet is deflected so as to point transversely to the wire. If the magnet be placed above the wire in which a current is flowing towards the north the north end of the magnet is turned towards the east, if it be placed below the wire the north end turns towards the west. Thus the current and the magnetic field which always accompanies it are definitely related. From this it follows that the magnet may be employed to de- termine the presence of a current flowing in any conductor and the direction may be at the same time determined. Moreover the amount of the deflection, other things being equal, depends on the strength of the current. This fact is the basis of several forms of galvanoscopes and galvanometers to be spoken of later. This discovery of Oersted at once attracted great attention, and many investigators un- dertook systematic researches with respect to it. Seebeck regarded the current as in itself a magnet, but Ampere, with much greater skill, commenced a series of investigations which were crowned with brilliant success. Seebeck noticed that a small floating magnet is attracted by the presence of an active conductor, and Arago found that iron filings will adhere to such a conductor, and that a sewing needle is not only attracted by the conductor but becomes permanently magnetic. In order to increase this effect he placed the needle in a small glass tube around which he wound the conducting wire in a spiral. It became magnetic as he had anticipated, and he showed that the direction of its polarity depends on the direc- tion of the current in the spiral. This was the foundation of the electromagnet. The. electromagnet in the form of a horse shoe was first made in 1825 by Stur- geon, an English electrician. It consisted of a bent iron core which was cov- ered with an insulating coating of varnish, upon which was wound spirally several turns of copper wire, the separate turns of the spiral being carefully sep- arated from one another. This magnet could lift a weight of nine pounds, a most marvelous result at that time.
1
91
HISTORY OF PARSONSFIELD.
Between the years 1828 and 1831 Professor Henry made many important inves- tigations, and reached results which were greatly in advance of any which had hitherto been obtained. He wound the horse-shoe shaped iron core with many turns of insulated wire and found, as he had expected, that the magnet's power was greatly enhanced. This was Henry's first important discovery. He said of it,-" When this conception came into my brain, I was so pleased with it that I could not help rising to my feet and giving it my hearty approbation." He con- structed many different electromagnets, some of which were wound with long, thin, insulated wires, continuously applied, while some were wound with several shorter wires which were parallel with each other and all united at their several ends so that the current could traverse them side by side and thus diminish the resistance which they offered to its passage. This latter arrangement he found specially adapted to be used with a battery consisting of few plates of large size, while the former could be used advantageously with a battery of many plates joined in series. A battery thus joined can overcome the resistance offered by a long wire such as must be employed in any system of telegraphy; and Henry at once perceived that by the use of his magnet wound with many turns of wire continuously applied, it would be possible to produce signals at any required distance. He also showed that this magnet thus acting at a distance might be made to close the circuit in which was placed one of his magnets adapted to act with a battery of few plates of large size, and thus to produce mechanical effects at any remote place. This is the method which was adopted by Morse in the practical telegraph system which is known by his name. One of the larger magnets constructed by Professor Henry, and now in the collection at Princeton College is capable of supporting 3500 pounds. Much larger and more powerful ones have since been constructed and employed in various researches and for practical purposes. The more exact statements of the relations which exist be- tween the strength of the current, the number of turns of wire and the amount of iron, etc., and the strength of the magnet, were made by Lenz and Jacobi, in 1839. So far as relates to the electromotive force of the battery, the resistance of the circuit and the strength of the resulting current, G. S. Ohm, in 1827, had reached conclusions by mathematical discussion which were identical with those which Henry had found by experiment.
Here must be mentioned another most important discovery which Ampere made in the latter part of the year 1820. He was led, by the similarity of the action of a wire conveying a current to a magnet, to try the effect of one wire upon another.when both are active as conductors. He sent currents through two neighboring wires, of which one was free to move, and found that when the currents move in the same direction the two wires attract one another, but when they move in opposite directions they repel one another. He devised various forms of apparatus by means of which he could examine the effects of currents on one another mutually at whatever angles he might choose.
e
92
HISTORY OF PARSONSFIELD.
He was led to a theory of magnetism which regards the molecules of a magnet as having minute currents of electricity circulating around them; but which regards these currents as circulating in all possible directions in the unmagnetized state. The act of magnetization would then consist in bringing more or less of these cur- rents into positions parallel with each other. The magnet will be saturated when all the currents are parallel. It is, then, easy to see why one magnet, when used to magnetize another loses none of its magnetism. Rotations of magnets around conductors of electricity, and of right conductors around magnets were foreseen as consequences of Ampere's theory and experiment fully justified these deductions. In the hands of Davy, Faraday and others these experiments have led to a very extensive doctrine of electro-dynamics, the details of which must be omitted. The whole matter has been treated rigorously by the mathematicians, among whom may be mentioned Ampere, Grassmann, Neumann, Weber, Maxwell, Thomson and others.
Seebeck held a peculiar view of the electromagnetic phenomena of Ampere, and in order to test it he formed a circuit composed wholly of two different metals, which of course, must be joined at two points. On heating one of the junctions he found that a current was produced. The same result, with the cur- rent in the reverse sense, followed the cooling of the joint. Thus was laid the foundation of the thermo-pile, by means of which heat may be applied to main- tain a constant current of electricity. The new apparatus was investigated by Henkel, the Becquerels, Mathiessen, Faraday, Gore and others. In short, it was found that all the effects which can be produced by the voltaic battery, can be secured by the thermo-pile. In its improved form, it consists of many bars of dissimilar metals, say antimony and bismuth, with their ends joined alternately and laid parallel with each other. When delicately made, the apparatus sets up a current with the slightest difference of temperature between its two faces. Oersted first employed it in investigating the radient heat. In 1839, Nobili fur- ther improved the apparatus and made it of the greatest use in measuring degrees of heat incredibly small, making use in connection with it of a very delicate gal- vanoscope devised by Schweigger. Besides its use in the physical laboratory this apparatus in modified forms has constantly rendered important service in the arts, and in physiological inquiries. Seebeck observed that the indications of the ap- paratus are not constant and proportionate to the degrees of heat to which it may be subjected. That is, as the temperature of one face of the pile rises the deviation of the needle may become proportionately less and less till at last a point is reached at which the indications will be reversed. Thomson and Tait have carefully studied this aspect of the matter, and tolerably satisfactory results have been reached, but they are too complicated for presentation here. It was early observed that the conducting wire which joins the poles of a galvanic bat- tery becomes heated on the passage of the current. In 1802 Davy showed that the rise in the temperature of the wire kept pace with the increase of chemical
93
HISTORY OF PARSONSFIELD.
decomposition in an electrolytic cell, placed in the circuit. In 1817 Oersted showed that the rise in the temperature of the conductor is proportional to the resistance which it offers to the passage of the current, but Joule, in 1841, deter- mined exactly the laws connecting the heat with the current and with the con- ductor, viz: the heat produced is directly proportional to the resistance and to the square of the strength of the current. Thus it becomes possible to measure the current strength by measuring the resistence of the conductor and the heat developed in it. Or, conversely, we can determine the heat which will be produced if we know the current and the resistance. These relations have become of the first importance in the modern applications of electricity in electric lighting and in the electrical transfer of energy from one place to another by means of the dynamo-machine.
Peltier, in 1839, made a discovery which is the converse of that of Seebeck already described. If a current be sent through a circuit composed of dissimilar metals, the joint between them will be cooled if the current move in the one direction and heated if sent in the other direction. This result might have been anticipated when it is remembered that heating such a joint sets up a current.
When the conducting wires of a powerful battery are separated a spark appears. Curtet, in Brussels, was the first to employ a piece of charcoal as one of the ter- minals of the conducting wires. The result was the production of the brilliant electric light now so well known. In 1812, Davy produced this light on a most magnificent scale, by the use of the great battery at his disposal in the Royal Institution. He noted that the charcoal which formed the positive terminal was hollowed out like a crater while the other remained but little altered. He, there- fore, rightly concluded that the phenomena is not due to combustion properly so called. On presenting the pole of a magnet he found that the electric arc could be deflected by it, just as if it had been a movable wire. The electric light, how- ever, did not come into general use because there was not known any economical way of producing the necessary currents of electricity.
Need help finding more records? Try our genealogical records directory which has more than 1 million sources to help you more easily locate the available records.