104 HANDBOOK OF THE TURF. 



whole series of exposures was made in the time occupied by a 

 single complete stride of the horse. A difficulty was experi- 

 enced in setting the apparatus in motion at the exact time 

 required, and to regulate it to correspond to the speed of the 

 horse. Accordingly, in later experiments, the following method 

 was devised to better represent the gaits of the horse, because 

 operated by his own movement. On the side of the track 

 opposite the building where the cameras were placed, a wooden 

 frame was erected, about fifty feet long, and fifteen high, at a 

 suitable angle, and covered with white cotton sheeting divided 

 by vertical lines into spaces of twenty-one inches, each space 

 being consecutively numbered. Eighteen inches in front of this 

 background was placed a baseboard twelve inches high, and on 

 which were drawn longitudinal lines four inches apart. In front 

 of this baseboard a strip of wood was fastened to the ground upon 

 the top of which wires were secured at an elevation of about one 

 inch above the ground and extending across the track. The wire 

 was exposed in a groove to one only of the wheels of the sulky, 

 being protected from contact with the horse's feet and the other 

 •wheel. Each wire was held in proper tension by a spring on the 

 back of the baseboard, so arranged that when the wire crossing 

 the track was depressed by the wheel it should draw upon the 

 spring connected with it, and make contact with a metallic but- 

 ton and complete the electric current. These wires were placed 

 at distances from each other corresponding with the cameras on 

 the opposite side of the track, and with the spaces between the 

 lines drawn on the background. Thus it will be seen that 

 the depression of the first wire would complete the circuit and 

 cause the magnet connected with the corresponding camera to 

 move the latch and liberate the shutters, exposing the sensitive 

 plate for a space of time, calculated by ]\Ir. IMuybridge at not 

 more than the five-thousandth part of a second. In like man- 

 ner, as the wheel passed over the second wire, the shutters 

 would be liberated on the second camera, and so on until the 

 whole series was discharged. This method was used in all 

 experiments where horses were driven to sulkies ; but when the 

 wheels were not used this arrangement with wires under the 

 track was modified, and a thread was drawn across sufficiently 

 high to come in contact with the horse's breast, and strong 

 enough to cause the contact and establish the circuit as before. 

 The number of cameras was afterwards increased to twenty- 

 four and they were placed at intervals of twelve inches to still 

 closer analyze the movements of the horse. " These experi- 

 ments," say the authors of the Exterior of the Horse, Messrs. 

 Goubaux and Barrier, "effected a veritable revolution in the 



