ZOOPBAXOQBAPHY 



INTRODUCTION. 



In the year 1872, while the Author was engaged in his 

 official duties as Photographer of the United States 

 Government for the Pacific coast, there arose in the 

 city of San Francisco one of those controversies upon 

 Animal Locomotion, which has engaged the attention 

 of mankind from the dawn of symbolical design, to 

 the present era of reformation in the artistic expres- 

 sion of animal movements. 



The subject of this particular dispute was the possi- 

 bility of a horse having all of his feet free of contact 

 with the ground at the same instant, while trotting, even 

 at a high rate of speed, and the disputants were Mr. 

 Frederick MacCrellish and the Hon. Leland Stanford. 



The attention of the Author was directed to this 

 controversy and he immediately sought the means for 

 its settlement. 



At this time the rapid dry plate had not yet been 

 evolved from the laboratory of the chemist, and the 

 problem before him was to develop a sufficiently in- 

 tense and contrasted image upon a wet collodion plate, 

 after an exposure of so brief a duration that a horse's 

 foot moving with a velocity of more than a hundred 

 lineal feet in a second of time, should be photographed 

 practically ' ' sharp. ' ' 



A few days' experimenting and about a dozen neg- 

 atives, with a celebrated fast trotter — *' Occident" — 

 as a model, while trotting at the rate of a mile in two 



