In a work which has more than one author, it is right to distinguish as far as possible what has been contributed by each.

The first part of this book, then, has been mainly composed by the present writer (who has acted as editor), and the second by Mr. Garnett; but it is due to Mr. Garnett to add that, while he had the chief share of the labour of collecting materials for the whole biography, and the entire burden of the account here given of Maxwell's contributions to science, the substance of Chapters XI. XII. XIII. is also largely drawn from information obtained through him. The matter of whole pages remains almost in his very words, although for the sake of uniformity and simplicity the first person has still been used in speaking of my own reminiscences.

The narrative of Maxwell's early life has been facilitated—(1) by a diary kept by Maxwell's father from 1841 to 1847, and often referred to in these pages as “the Diary;” (2) by two albums containing a series of water-colour drawings by Maxwell's first cousin, Mrs. Hugh Blackburn (née Isabella Wedderburn), the value of which may be inferred from the outlined reproductions of a few of them prepared by Mrs. Blackburn herself as illustrations for this book. They are literally bits out of the past, each containing an exact representation, by a most accurate observer and clever draughtswoman, of some incident which had just happened when the sketch was made.

At the close of the memoir published in the Proceedings of the Royal Society, Mr. W. D. Niven, referring to Maxwell's scientific work, says:—

It will probably be many years before an approximate estimate can be formed of the value of Maxwell's work. In the following pages no attempt has been made to give more than a brief account of a few of his principal contributions to science. The chief subjects referred to have, for convenience, been arranged in the following order:—

1. Experiments on Colour Vision and other contributions to Optics.

2. Investigations respecting Elastic Solids.

3. Pure Geometry.

4. Mechanics.

5. Saturn's Rings.

6. Faraday's Lines of Force, and Maxwell's Theory of the Electro-magnetic Field, including the Electro-magnetic Theory of Light and other investigations in Electricity.

7. Molecular Physics.

The Chair of Experimental Physics in the University of Cambridge was founded by a Grace of the Senate on the 9th of February 1871.

In October 1870 the Duke of Devonshire, who was Chancellor of the University, had signified his desire to build and furnish a Physical Laboratory for Cambridge. In acting as a member of the Royal Commission on Scientific Education, he had perceived how useful such an institution might be made. It was in connection with the acceptance of this munificent offer that the new professorship was established by the Senate.

The question, who should be the first professor? was for some time attended with anxiety. It was understood that Sir William Thomson had declined to stand, and it was thought uncertain whether Clerk Maxwell could be persuaded to leave the retirement of his country-seat. After some hesitation, arising chiefly from genuine diffidence, he was induced to become a candidate, on the understanding that he might retire at the end of a year, if he wished to do so. His candidature was announced on the 24th of February. There was no opposition, and he was appointed on the 8th of March.

The first school-days are not always a time of progress. For one whose home life has been surrounded with an atmosphere of genial ideas and liberal pursuits, to be thrown, in the intervals of “gerund grinding,” amongst a throng of boys of average intelligence and more than average boisterousness, is not directly improving at the outset. Not that Maxwell ever retrograded—for his spirit was inherently active; but where the outward environment was such as awakened no response in him, he was like an engine whose wheels do not bite—working incessantly, but not advancing much. If the Scottish day-school system had not still been dominated by a tyrannous economy, and by that spirit of laisser faire which in education is apt to result in the prevalence of the worst, much that was in Maxwell would earlier have found natural vent and growth. As it was, he was of course storing up impressions, as under any circumstances he would have been; but his activities were apt for the time to take odd shapes, as in a healthy plant under a sneaping wind. Or, to employ another metaphor, the light in him was still aglow, but in passing through an alien medium its rays were often refracted and disintegrated. The crowd of “aimless fancies,” whose influence upon his life he so touchingly deprecated at a later time, were now most importunate; and, bright and full of innocence as they were, they produced an effect of eccentricity on superficial observers which he afterwards felt to have been a hindrance to himself.