PREFACE, 
HIS volume is made up of sketches 
reprinted from various periodicals, and 
coming under the general head of popular 
science. Most of these articles have been 
freely retouched since their original appear- 
ance. The volume corresponds in part to 
the first edition of “Science Sketches,” pub- 
lished in 1887. Eight of the articles are the 
same, being printed from the same plates, 
with a few verbal changes. For certain 
others of the first edition, — the accounts of 
“ Agassiz at Penikese,” “The Fate of Icio- 
dorum,” “The Story of a Strange Land,” 
and * How the Trout came to California,” — 
articles written since 1887 have been sub- 
stituted. The author wishes to express his 
especial obligations to Messrs. D. Appleton 
