18 TRENCHING AND SUBSOILING 



which the transmission pulley is fixed, connected by a belt 

 to a horse-gin or portable engine. If an effort P is applied 

 on the pulley p, the pinion r will revolve the wheel R, the 

 pinion r will revolve the wheel R' and the drum t, and if a 

 rope is coiled on the drum at the extremity of which is a 

 resistance Q, in the form of a load to be hauled, the load will 

 gradually move towards the machine. Disregarding fric- 

 tional losses and the rigidity of the rope, 



/, being the radius of the pulley ; 

 a, the radius of the drum ; 



R, R', r, r' 9 the radii of the toothed wheels, or the- 

 number of their teeth ; we have, theoretically 

 . P r r a p o r r a 



-Q RKTi' ( Q R~IT7 



As a r r are always very small compared to R R' and L. 

 P is very small compared to Q, we can, with the toothed 

 wheel gearing train, overcome considerable resistances, 

 which, with the simple capstan, would have been impossible. 

 But we must not forget that this gain in power, and conse- 

 quently diminution of velocity, corresponds to a loss of time 

 so much the greater as the gain in itself is higher. 



It is surprising to notice that the wheel-and-axle principle- 

 so extensively applied for a long time in other industries, and 

 constructed under so many different forms and dimensions, 

 has been so tardily applied for the draught of agricultural 

 implements. 



Deforges, constructing engineer, in an interesting report, 

 after a special competitive show of horse-gins and winding- 

 drums held at Narbonne in 1888, relates that before 

 1815 an old sailor in the Departement of the Pyrn6es 

 established a capstan at the end of a small field, by means 

 of which he hauled his plough, and consequently cultivated 

 his land. In the same report, Aubert, a land-owner, in the 

 Departement of Basses-Alpes, is also mentioned as having 

 used a capstan for hauling his ploughs in 1834. But these 

 isolated trials remained for very many years without 

 creating a movement in favour of these devices. 



Nothing less than the destruction of vines by phylloxera 

 and the general necessity of reconstituting the different 

 vineyards was necessary to compel attention to the merits of 

 these machines. 



