vi PREFACE. 
& Company for permission to reprint the 
six articles which have appeared in the 
“Popular Science Monthly.” He is also 
indebted for similar permission to the pub- 
lishers of the “ American Naturalist,” “St. 
Nicholas,” “ Recreation,” and the “Riverside 
Natural History,” from each of which pub- 
lications one article has been taken. 
LELAND STANFORD JR. UNIVERSITY, 
PaLo ALTO, CaL., April 30, 1896. 
