Q /6V 

 T-S-7 



PREFACE. 



LEARNED mathematician of the seventeenth cen- 

 tury, Ozanam by name, a member of the Academy 

 of Sciences and author of several distinguished 

 works, did not think it derogatory to his dignity 

 to write, under the title of " Mathematical and 

 Physical Recreations," a book designed for the 

 amusement of youth, in which science lends itself 

 to every pastime, even jugglery and tricks of legerdemain. 



"Jeux d' esprit" says Ozanam, "are for all seasons and all 

 ages ; they instruct the young, they amuse the old, they are 

 welcomed by the rich, and are not above the reach of the poor." 



The object of the book now presented to the reader is also 

 to instruct while it amuses, but we have not thought proper to make 

 use, as Ozanam did, of any physical feats, so called amusing. Such 

 do not constitute experiments, and are but ingenious deceptions, 

 intended to disguise the true mode of operation, and we have not 

 desired to make use of or popularise such methods. We wish, on 

 the contrary, that every game we describe, every pastime or amuse- 

 ment of which we give the exposition, should be rigorously based on 

 the scientific method, and looked upon as a genuine exercise in 

 physics, chemistry, mechanics, or natural science. It does not 

 appear to us desirable to teach deception, even in play. 



Science in the open air, in the fields, in the sunshine, is our first 

 study ; we point out how, in the country, it is possible, pleasantly 

 and unceasingly, to occupy one's leisure in observing nature, in 

 capturing insects or aquatic animals, or in noting atmospheric 

 p^ nomena. 



We next teach a complete course of physics without any appa- 

 .tus, and point out the methods for studying the different phenomena 



280 



