Page:Dictionary of National Biography volume 37.djvu/135

121 take that step which the master himself in his ‘Electricity and Magnetism’ confessed himself unable to take, and to explain the mechanism at one time of light, electricity, and magnetism. The paper on the electro-magnetic field was in time expanded into the great ‘Treatise on Electricity and Magnetism,’ published in 1873, on the second edition of which Maxwell was at work at the time of his death.

But it is not only on the theoretical side of electricity that advance is due to Maxwell. He realised, like Lord Kelvin, that a carefully thought-out system of measurement was essential for its progress, and that accurate experiment was needed to form a foundation for his theory. Maxwell became a member of the newly formed electrical standards committee of the British Association in 1862, and was one of the sub-committee appointed to construct the standard of resistance. The necessary experiments were carried out in his own laboratory at King's College, and the results, which have been so fruitful to electrical science, are recorded in the ‘Reports’ of the committee for 1863 and 1864. The ‘Report’ for 1863 contains an appendix by Maxwell and Fleeming Jenkin ‘On the Elementary Relations between Electrical Measurements,’ in which the fundamental principles involved are stated with unrivalled accuracy and clearness.

Another important series of experiments, those on the velocity of propagation of electro-magnetic waves, is described in the paper ‘On a method of making a direct Comparison of Electrostatic with Electro-magnetic Force; with a Note on the Velocity of Light’ (Phil. Trans. vol. clviii). Maxwell's numbers showed that this velocity was nearly that of light; more recent work has proved that the two are, within the limits of error of very exact experiments, identical.

The theory Maxwell formulated is day by day gaining more and more acceptance; the foremost physicists throughout the world are engaged in working at it, and in developing ideas, the germs of which may nearly all be traced in the ‘Electricity and Magnetism’ or in the paper on the ‘Electro-magnetic Field.’

Besides the books already mentioned Maxwell published in 1879 the ‘Electrical Researches’ of Henry Cavendish, written between 1771 and 1781; edited from the original manuscripts in the possession of the Duke of Devonshire, K.G.; he also wrote a text-book of ‘Heat’ and a small treatise on dynamics called ‘Matter and Motion.’ After his death an elementary treatise on ‘Electricity,’ which was left unfinished, was completed and published by Professor Garnett. Among his other papers are some on ‘Geometrical Optics,’ which contain important results, and several published mostly in the ‘Transactions of the Royal Society of Edinburgh,’ ‘On Reciprocal Figures and Diagrams of Force.’ A memorial edition of his scientific papers, undertaken by a committee appointed soon after his death, was edited by Mr. W. D. Niven, and was issued from the Cambridge University Press in 1890, 4to.

As a man Maxwell was loved and honoured by all who knew him; to his pupils he was the kindest and most sympathetic of teachers, to his friends he was the most charming of companions; brimful of fun, the life and soul of a Red Lion dinner at the British Association meetings, yet in due season grave and thoughtful, with a keen interest in problems that lay outside the domain of his own work, and throughout his life a stern foe to all that was superficial or untrue. On religious questions his beliefs were strong and deeply rooted; the words which close his lecture on molecules, expressing his faith in ‘Him, who in the beginning created not only the heaven and the earth, but the material of which heaven and earth consist,’ have often been quoted.

There is a bust by Boehm in the Cavendish Laboratory, and also a portrait painted by his cousin, Miss Wedderburn. The bust was executed after his death from G. J. Stodart's engraving, which forms the frontispiece to his works; and a portrait by Mr. Lowes Dickenson, based on the same engraving, was presented to Trinity College by the subscribers to the memorial fund.

By his will he left funds to found a studentship in experimental physics open to members of the university of Cambridge. This was carried out in 1890, when, by the death of Mrs. Maxwell, the university came into possession of the property.

[Life by Professor Lewis Campbell of St. Andrews, and Professor Garnett, his Demonstrator at the Cavendish Laboratory, 1882.] 

MAXWELL, JOHN, of Terregles,, and afterwards fourth  (1512?–1583), partisan of Mary Queen of Scots, second son of Robert, fifth lord Maxwell [q. v.], by Janet Douglas, daughter of Sir William Douglas of Drumlanrig, Dumfriesshire, was born about 1512, and was educated at Sweetheart Abbey, Kirkcudbrightshire (document at Terregles, quoted in Book of Caerlaverock, i. 497). As tutor to his nephews, and presumptive heir to them and his brother, he was for some time known as