ABSTRACT
Anything written by Heinrich Hertz is of interest; and Miscellaneous papers are of interest, not only on this account, but also on account of their suggestiveness. It is always a question as to the desirability of republishing and translating papers published some years ago. Prof. Philipp Lenard has earned much gratitude for his Introduction. It gives a charming picture of Hertz, of his simplicity, his devotion to science, his loving regard for his parents. In considering the cracking of a material like glass, Hertz seems to think that its cracking will depend only on the tension; that it will crack where the tension exceeds a certain limit. In 1883 Hertz published a deduction from first principles of Maxwell’s equations for the electromagnetic field in the symmetrical form, afterwards used by himself in his investigations on oscillatory discharge waves. The concluding article, on his master Helmholtz’s seventieth birthday, is a noble and generous tribute to that great teacher’s abilities and character.
