76o THE POPULAR SCIENCE MONTHLY. 



formed by a hunting expedition to the next Sierra Nevada than by all 

 the homilies of Fray Gerundio. Like depraved humors, prurient pro- 

 pensities yield to active exercise more readily than to physic and 

 prayer. Hunting tribes are generally continent, stalwart, and comely ; 

 wood air is a cosmetic ; the finest types of the human form are not 

 found within the precincts of the Palais Royal, but in the Caucasus 

 and the Kentucky forest counties. 



Enjoyable winter excursions are a privilege of the rich ; still, a pair 

 of good skates make a convenient pond or a small river a great bless- 

 ing. From a sanitary point of view, the neighborhood of larger 

 streams is not so much of an advantage ; besides being the terror of 

 parents during the skating season, a big river is apt to render the con- 

 tiguous lowlands more or less malarious, especially after every inunda- 

 tion. In snow-bound villages children have to depend mainly on in- 

 door exercises ; cold air, however, is a powerful tonic, and a two hours' 

 snowball-fight will generally suffice to vitalize a juvenile constitution 

 for a couple of days. Mountain air, too, is a peptic stimulant, and 

 pedestrian excursions are doubly invigorating if they include a good 

 deal of up-hill work. 



For those who wish to select their dwelling-place with regard to 

 the hygienic interest of their children, the best location is, therefore, 

 on the whole, the bank of a small river in the neighborhood of a large 

 mountain-range. 



-- 



HISTORY OF CHRONOLOGY. 



By Professor E. S. BUKNS. 



CHRONOLOGY is the science of the measurement of time, of 

 ascertaining and fixing dates, which constitute the landmarks by 

 which the mind is guided in its backward course through the long 

 vista of years, and enabled to locate and fix the events of history, the 

 knowledge of which would otherwise be a confused and wellnigh 

 useless attainment. The advanced state of astronomical science and 

 the experience of those who have gone before us have enabled us to 

 reduce all that pertains to this subject to so complete a system that 

 we lose sight of its magnitude and importance ; we forget the slow 

 progress and toilsome research which the great minds of past centu- 

 ries had to undergo to reach the present state of correctness. To 

 appreciate even faintly this magnitude, we must transport ourselves 

 backward a few thousand years, and forget, if we can, the improve- 

 ments of modern astronomy, the developments of mathematics, and, 

 above all, the universality and ubiquity of modern almanacs. 



The first and most obvious division of time is the day the time 

 required for a revolution of the earth upon its axis which could not 



