viii PREFACE 



the progress of modern science. Every intelligent 

 person, whatever his professional interests, has a nat- 

 ural curiosity to know something about the new things 

 in science, as well as in art, literature, drama, and world 

 events. But it is not so easy to keep in touch with the 

 advancement of science since comprehensible compen- 

 diums of recent researches are hard to find. At the end 

 of each chapter there has been appended a list of several 

 recent and reliable books and articles, both technical 

 and popular, for the convenience of readers who seek 

 further information. 



The reader will notice that in almost every chapter 

 there is given, besides an explanation of recent discov- 

 eries and applications, some account of the efforts that 

 have led to them and of the personalities concerned 

 in them. This unusual feature is due to a theory of 

 the editors of the volume that more attention should 

 be paid to scientific history and biography. They be- 

 lieve that one of the reasons why science is commonly 

 regarded by the public as dry is that it has been too 

 completely divested of its human interest. It is im- 

 portant for the public to understand that scientific 

 progress is not a mere series of the lucky accidents and 

 happy inspirations of a few favoured individuals, but 

 a long and toilsome process of investigation, hypothe- 

 cation, and verification on the part of many workers 

 who often follow fallacious theories and turn into blind 

 alleys from which they have to find their way back to 

 the highway leading toward truth. 



OTIS W. CALDWELL. 



