IN the history of science, names such as those of Galileo, Newton, Faraday, Darwin, Helmholtz, and Kelvin stand out like the peaks of a great range of mountains amid the surrounding lesser heights. One such name is that of Maxwell, the centenary of whose birth falls on June 13, and to whose memory homage will be paid at Cambridge in October by Profs. Einstein, Planck, Langevin, and others. Maxwell's work belongs to the third quarter of the nineteenth century, and fifty-eight years have now passed since the appearance of his “Treatise on Electricity and Magnetism”, but the passing of time has shown much of his work to be of fundamental importance, and there is no investigator of physical subjects who does not owe something to him. He died at the age of forty-eight, when in the prime of life, a man loved and honoured by all who knew him, for the kindliness of his disposition and the charm of his character. Of his writings, it has been said that every one of them is stamped with the subtle and unmistakable impress of genius.