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Hippolyte Pixii, a French instrument maker, constructed the first direct current dynamo in 1832. This was the first practical mechanical generator of electrical current that used concepts demonstrated by Faraday. The machine contained a permanent magnet which was rotated by a hand crank. The spinning magnet was positioned so that its north and south poles passed by a piece of iron wrapped with wire. Pixii found that the spinning magnet produced a pulse of current in the wire each time a pole passed the coil. Furthermore, the north and south poles of the magnet induced currents in opposite directions.
William Sturgeon built an electric motor in 1832 and invented the commutator, an integral part of most modern electric motors. He also improved the voltaic battery and worked on the theory of thermoelectricity. From more than 500 kite observations he established that in serene weather the atmosphere is invariably charged positively with respect to the Earth, becoming more positive with increasing altitude.Sturgeon founded the journal "Annals of Electricity" in 1836 and edited it until it folded in 1843, 10 volumes after its start. His journal was the first of its type on electricity in England. Also in 1836, he invented the first suspended coil galvanometer, and thereafter several electromagnetic machines of various types.
John Daniell began experiments in 1835 in an attempt to improve the Voltaic battery with its problem of being unsteady and as a weak source of electrical current. His experiments soon led to remarkable results. In 1836, he invented a primary cell in which hydrogen was eliminated in the generation of the electricity. Daniell had solved the problem of polarization. In his laboratory he had learned to alloy the amalgamated zinc of Sturgeon with mercury. His version was the first of the two-fluid class battery and the first battery that produced a constant reliable source of electrical current over a long period of time. That is, the power remained constant with this type of battery upon repeated application without removing the metals which was a source of weakness in all single fluid batteries. Until now the current of other batteries declined rapidly. His placement of a barrier between the copper and zinc plates stopped the hydrogen from forming.
Nicholas Joseph Callan creates the first induction coil in 1836. He took a horseshoe shaped iron bar and wound it with thin insulated wire and then wound thick insulated wire over the windings of the thinner wire.
| He discovered that, when a current sent by battery through a "primary" coil (a small number of turns of thick copper wire around a soft-iron core) was interrupted, a high voltage current was produced in an unconnected "secondary" coil (a large number of turns of fine wire). Callanalso produced the first transformer by using wires of different sizes in the windings. The three secondary coils contain a total of 150,000 feet of fine iron wire. The primary coil is made of copper tape, wound around a core of iron wires. |
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William Grove produced the first fuel cell in 1839. He based his experiment on the fact that sending an electric current through water splits the water into its component parts of hydrogen and oxygen. So, Grove tried reversing the reaction - combining hydrogen and oxygen to produce electricity and water. This is the basis of a simple fuel cell. The term “fuel cell” was coined later in 1889 by Ludwig Mond and Charles Langer, who attempted to build the first practical device using air and industrial coal gas.
William Grove also introduced a powerful battery at the annual meeting of the British Association for the Advancement of Science in 1839. Grove's first cell consisted of zinc in dilute sulfuric acid and platinum in concentrated nitric acid, separated by a porous pot (Grove Battery). The cell was able to generate about 12 amps of current at about 1.8 volts. This cell had nearly double the voltage of the first Daniell cell. Grove's nitric acid cell was the favorite battery of the early American telegraph (1840-1860), because it offered strong current output.
As telegraph traffic increased, it was found that the Grove cell discharged poisonous nitric dioxide gas. Large telegraph offices were filled with gas from rows of hissing Grove batteries. As telegraphs became more complex, the need for constant voltage became critical and the Grove device was necessarily limited (as the cell discharged, nitric acid was depleted and voltage was reduced). By the time of the American Civil War, Grove's battery was replaced by the Daniell battery. In 1841 Bunsen replaced the expensive platinum electrode used in Grove's battery, with a carbon electrode. This led to large scale use of the "Bunsen battery" in the production of arc-light and in electroplating.
At that time, it was beliefed that organic and inorganic compounds are independent from each other, and that organic compounds could only be created by living organisms. Adolf Kolbe believed that organic compounds could be derived from inorganic ones, directly or indirectly, by substitution processes. He validated his theory by converting carbon disulfide (considered as an inorganic material), in several steps, to acetic acid (typical organic compound) (1843-45). Thus, he was the first to synthesize of an organic compound from inorganic maretial. Previously organic chemistry had been devoted to compounds that occur only in living organisms. Kolbe also synthesized salicylic acid and showed its value as a preservative. The process was named Kolbe synthesis (or Kolbe-Schmitt reaction), which works by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure (100 atm, 125°C), then treating it with sulfuric acid
Alexander Bain was able, in 1846, to electrochemically reproduce conventional graphic signs using paper soaked in potassium ferrocyanide. Bain's idea was taken up and even surpassed by Bakewell, who was able to send written script. Nonetheless both Bain and Bakewell's systems were unsuitable. His most important work was on the electrolysis of the fatty (alkanoic) acids. He was first to apply electrolysis to organic synthesis and showed that electrolysis of carboxylic acids effects decarboxylation; identified carbonyl as a functional group. During the reaction CO2 is cleaved off. The alkyl radicals dimerize to symmetric compounds
 | The reception obtained with Bakewell's method was poor, lacking synchronism between transmitter and receiver. Giovanni Caselli overtook both of them with his electrochemical pantelegraph or Universal Telegraph, but also included a "synchronizing apparatus" to help two machines work together. This unique machine was a precursor of commonly known since the 1980's fax machine. Once completed, the final device met with unequivocal enthusiasm from the Parisian scientific world and a Pantelegraph Society was created to prepare its exploitation. |
Made of cast iron and standing more than 2 m high, this primitive, but effective machine worked as follows. The sender wrote a message on a sheet of tin in non-conducting ink. The sheet was then fixed to a curved metal plate. The stylus of the transmitter scanning an original document by moving across its parallel lines (three lines per millimeter). The signals were carried by telegraph to the marked out the message in Prussian blue ink, the color produced by a chemical reaction, as the paper was soaked in potassium ferrocyanide. To ensure that both needles scanned at exactly the same rate, two extremely accurate clocks were used to trigger a pendulum which, in turn, was linked to gears and pulleys that controlled the needles.
Wilhelm Weber developed, in 1846, the electrodynamometer, in which a current causes a coil suspended within another coil to turn when a current is passed through both. In 1852, Weber defined the absolute unit of electrical resistance.
Johann Hittorf's early investigations were on the allotropes (different physical forms) of phosphorus and selenium. Between 1853 and 1859 his most important work was on ion movement caused by electric current. In 1853 Hittorf noticed that some ions traveled more rapidly than others. This observation led to the concept of transport number, the rate at which particular ions carried the electric current. Hittorf measured the changes in the concentration of electrolyzed solutions, computed from these the transport numbers (relative carrying capacities) of many ions, and, in 1869, published his laws governing the migration of ions.
Isaak Adams Jr. pioneered nickel electroplating while studying under Josiah Parsons Cooke at Harvard from 1858 to 1860. He was unable to repeat this feat in the winter 1865-66 while engaged in nickel plating over 100 gross of gas burner tips. Faced with this inconsistency in 1866, he investigated the effect of such impurities as zinc, arsenic, copper and iron on the electrodeposition of nickel. He found that nickel deposited best in neutral or slightly acid solutions, in the range between neutral litmus and Congo red paper. Adams also found that cast nickel anodes could be produced which dissolved satisfactorily to maintain the solutions during plating.
Primary cell batteries eventually lost all of their electricity when the chemical reactions were spent. In 1859 Gaston Planté immersed lead plates in diluted sulfuric acid and proved current repeatedly through them, therefore producing the first rechargeable battery, a system still widely used today! His cell used two thin lead plates separated by rubber sheets. He rolled the combination up and immersed it in a dilute sulfuric acid solution. Initial capacity was extremely limited since the positive plate had little active material available for reaction. Planté had positively charged one of his plates, making it lead oxide. The other was simply lead, which had a negative charge. His breakthrough was to create a flow of electrons from the negative plate, up out of the battery as electricity, then to feed the flow back into the battery, making the world's first rechargeable, or secondary, battery.
In 1866, Georges Leclanché patented a new system, which was immediately successful. Leclanche's original cell was assembled in a porous pot. The positive electrode consisted of crushed manganese dioxide with a little carbon mixed in. The negative pole was a zinc rod. The cathode was packed into the pot, and a carbon rod was inserted to act as a currency collector. The anode or zinc rod and the pot were then immersed in an ammonium chloride solution. The liquid acted as the electrolyte, readily seeping through the porous cup and making contact with the cathode material. Leclanché's "wet"cell (as it was popularly referred to) became the forerunner to the world's first widely used battery, the zinc carbon cell.
