In the attempt to measure the duration of a flash of lightning, Mr. A. C. Raynard, in Knowledge, regards a recurrent flash as "a very complicated succession of discharges lasting for an appreciable part of a second. The giant discharges which take place during a storm, between irregularly shaped and badly conducting masses, differ materially in character from the flashes produced in a laboratory between good conductors. In the laboratory the whole flow takes place at once. In nature there seems to be a flow or rash succeeded by a dribble, which ceases or nearly ceases, and commences again and again, flow after flow rushing down the same path until the potential along the line of discharge is realized." The appearance of "ribbon-flashes" in some of the photographs is supposed to be due to unsteadiness or imperfections in the instruments. The present greater proportion than formerly existed of men who are active and vigorous after passing seventy years of age, and all the way even up to ninety, denotes one of the brighter phases of our civilization. The fact that such vigor is associated with different physical types, both suggests that there may be a general origin for it, and feeds the hope that it may partly depend on personal conduct. Dr. B. W. Richardson advises that the preparation to secure long life may begin with the training of children, by protecting them against mental disturbance as well as physical hardship; and may be carried out in more mature life by combining, with hygienic living, healthful activity of mind with lively interest in all things that make for good, while restraining or avoiding passion, undue excitements, and unlovely qualities.