experiments upon ‘The Thermo-Magnetism of Homogeneous Bodies’ he endeavoured to discover a definite law of action, and in his paper ‘On the Theory of Magnetic Electricity’ he attempted ‘to reduce the phenomena of magnetic electricity to a definite code of physical laws.’ But he moved very cautiously, being conscious, as he says, of the ‘long silent probation’ that is needed before broad statements ‘can be of any account beyond expanding the region of philosophical speculation.’
His practical inventions covered the whole field of electrical science. Jacobi of St. Petersburg claimed for Sturgeon, in conjunction with Oersted, the discovery of the electro-magnetic engine. No less firmly established, says Joule, is his priority in regard to the magneto-electrical machine. He was the first who devised and executed an apparatus for throwing the opposing currents into one direction, thus accomplishing for this machine exactly what James Watt accomplished for the steam engine. This contrivance, known as the commutator on the continent, and formerly unitress in America, is now universally employed in every magneto-electrical machine. Sturgeon was without doubt the constructor of the first rotary electro-magnetic engine. The (now universally adopted) amalgamation of zinc plates in the voltaic battery was originated by him, while his discoveries in the thermo-electricity and magnetism of homogeneous bodies have placed his name higher than that of any other man of science who, after Seebeck, has cultivated thermo-electricity. Sturgeon clearly perceived the possibilities of the electro-magnet as a motor. And this same invention of the soft-iron electro-magnet has long been the leading feature of the instrument working the Morse system of electricity, while it has also proved the parent of the dynamo machine, which has exerted enormous influence upon modern industrial life.
Sturgeon's inventive efforts were constantly directed towards the simplifying and cheapening of apparatus, and so rendering his discoveries more practically available in the development of the scientific industries. Thus, for example, a Grove's battery, costing at the time 7l., and a Daniel's 6l., were superseded by Sturgeon's batteries of equal power for 3l. 10s.
With the prevision of genius, Sturgeon foresaw that electricity would become the prevailing illuminant. Exhibiting the electric light actuated by a galvanic battery of one hundred jars at one of his lectures in 1849, he said that he ‘quite anticipated that the electric light would supersede gas for public, whatever it might do for private, purposes.’ He also showed the process of electro-gilding by a magnetic machine of his own construction, and translated from the German of Professor Jacobi ‘The Whole Galvanoplastik Art or Method of forming Electrotypes of Medallions, Coins, Statuary, Bronzes, Ornaments, &c.’ Several of these inventions were afterwards patented at Woolwich and Birmingham; but Sturgeon was not benefited, as his desire was to place ‘this apparatus in the hands of the public, and [to make it] alike available to all artisans wishing to employ it.’
Only a few weeks before his death Sturgeon completed, in one large and handsome volume, a reprint of his original contributions to science (scattered through numerous periodicals) under the title of ‘Scientific Researches.’ This volume was published by subscription (Manchester, 1850, 4to), and was illustrated by a number of finely engraved plates. Of the papers contained in this volume, the earlier ones had first seen the light in the ‘London Philosophical Magazine.’ To this periodical Sturgeon's chief contributions, all on electrical subjects, were as follows: September 1823 (a description of the revolving ‘Sturgeon's disk,’ a modification of the pendulum of Marsh and the star-wheel of Barlow); February, April, October 1824, May and June 1825, June 1826 (ignition of gunpowder by electrical discharge); January 1827, July, August 1831, March 1832 (on electro-magnets); April, May, July 1832, January, February, March, May, November 1833, November and December 1834 (kite experiments); April and November 1835, and August 1836. To the ‘Edinburgh Philosophical Journal’ (July 1825) Sturgeon contributed an investigation of the action of magnets upon non-ferruginous metals. His ‘Researches in Electrodynamics,’ a paper read before the Royal Society on 16 June 1836, was not printed in the ‘Philosophical Transactions,’ but it is given in full, with an explanation of a temporary friction between Sturgeon and Faraday, in the quarto ‘Researches’ (No. xii.). Sturgeon's ‘Address to the London Electrical Society on 7 Oct. 1837,’ and four papers read before the society, are printed in the ‘Electrical Society's Transactions,’ 1837 and 1838. From 1836 to 1843 Sturgeon's activity is best traced in the pages of his own periodical, the ‘Annals of Electricity.’ In October 1839 a paper which there appeared upon ‘Marine Lightning Conductors’ led to an animated controversy with Sir William Snow Harris [q. v.] Sturgeon
