INTRODUCTION. 5 



minutes and sixteen seconds, laterally in front of the 

 camera, decided the argument for once and for all 

 time in favor of those disputants who held the opinion 

 that a horse while trotting was for a portion of his 

 stride entirely free from contact with the ground. 

 With a knowledge of the fact that some horses while 

 trotting will make a stride of twenty feet or more in 

 length, it is difficult to understand why there should 

 ever have been any difference of opinion on the subject. 



These first experiments of Zoopraxography were 

 made at Sacramento, California, in May, 1872. A 

 few impressions were printed from the selected nega- 

 tive for private distribution, and were commented upon 

 by the "Alta California," a newspaper published in 

 San Francisco. 



Thus far the photographs had been made with a 

 single camera, requiring a separate trotting for each 

 exposure. The horse being of a dark color and the 

 background white, the pictures were little better than 

 silhouettes, and it was difficult to distinguish, except 

 by inference, the right feet from the left. 



Several phases of as many different movements had 

 been photographed, which the Author endeavored 

 with little success to arrange in consecutive order for 

 the construction of a complete stride. 



It then occurred to him that if a number of cameras 

 were placed in a line, and exposures effected succes- 

 sively in each, with regulated intervals of time or of 

 distance, an analysis of one single step or stride could 

 be obtained which would be of value both to the 

 Scientist and the Artist. 



The practical application of this system of photo- 



