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necessitated, our colleague, P. Ferrouillat, then Professor of 

 Agricultural Engineering at the National School of Agri- 

 culture, Montpellier, expressed the following views in the 

 Progres Agricole of 1891 (see page 63). 



In 1888, -a special competitive show of capstans was held 

 at Narbonne. More than one hundred were then in use in 

 the South of France for the preparation of land for recon- 

 stitution purposes. In 1890 another competitive show was 

 held at Perpignan. The widespread use of these machines 

 in the South of France and Algeria dates from that time. 



HORSE-GINS. 



Horse-gins* consist essentially of a drum or cylinder, 

 A (Fig. 32), revolving round a vertical axle a. The horse 

 M is yoked at the end of a pole L, to which the bridle is 



Fig. 32. Diagram of a Horse-gin. 



also connected by a wooden rod b. When the pole is clamped 

 on the drum by means of cotters or pins the horse in his 

 movement revolves the drum which winds the cable C, at 

 the extremity of which the plough is fastened. The motor 

 M, exerts a mean effort F, a part of which /, only is utilized ; 

 the latter being the projection of the effort F on the perpen- 

 dicular to the radius passing by the yoking hook,t the other 

 component y v , simply increases the pressure of the drum 

 on its axle. It is, therefore, advisable to diminish f 

 (prejudicial force), and increase f (useful force), by giving 

 the greatest possible length to the pole. In practice it does 

 not exceed 16 \ feet. 



For heavy work, instead of using a single horse, two or 

 six may be yoked to corresponding poles fixed in the socket 



* In mechanics, in the study of simple machines a wheel revolving round 

 a vertical axle (as we are studying here) is called a capstan. We will, 

 however, use the word gin, which is now accepted in practice. [Trans.] 



f See Traite de mecauique experimentale, p. 112. 



