Ch. III.] DOUBLE ROLLERS. 35 



weights to their axis. The expense of tliese instruments, though now less, 

 in consequence of tlie fall in the price of iron, than it was some years ago, 

 is, however, so very considerable, that one of them is mentioned, in the Nor- 

 folk Report, as being in use in ihe park at Holkhain, wliich cost 60Z. ; it 

 was cast at the Carron foundry, is five feet six inches in diameter, as well as 

 length, and is drawn by four horses. 



HoUolo wooden rollers can, however, be constructed with much less cost, by 

 simply getting three broad wheels of the proposed diameter, ])laced one in the 

 centre and the other tuo at each end, and through the naves of which an 

 iron axle is to be fixed, which runs the whole of the intended length and 

 fastens them together. Upon these, strong planks, cut very narrow, and 

 bevelled at the edges, are to be firmly nailed lengthwise until the roller is 

 completely covered ; it may then be mounted in the usual manner, and the 

 weights may be hung in the same way as in the iron roller. We have 

 lately seen one of these, made by a farmer and one of his men out of the 

 wheels, stripped of their tire, and shafts of a worn-out three-wheeled tumbril, 

 which perfectly answers the intended purpose; and the whole cost of which, 

 for smith's work and jjlank, exclusive of the old materials, did not amount 

 to much more than twenty shillings. 



These liollow rollers are also sometimes made of an octagon shape, which 

 do heavy work better than those which are round, because each turn brings 

 the flat surface with more force to the ground ; but they require greater 

 strength to draw them. Mr. Malcolm mentions having seen one of them 

 at work which weighed about a ton and a quarter, and executed the opera- 

 tion so well, that it was constantly borrowed by the neighbouring farmers: 

 it was five feet in diameter, cut into as many sides as there were spokes in 

 tiie wheel, and the axletree was sixteen inches in diameter*. 



DOUBLE ROLLERS, 



in the form of the common cylinder, divided into two pieces, dis- 

 tant about an inch from eacli other, and moving each on its own axis, 

 are sometimes used, both for the convenience which they afford in 

 turning, and for laying a more equal pressure upon ridgy land, and in these 

 respects are certainly to be recommended. Long rollers, wlien turned short 

 at the extremity of a field, having only the same direction at one end, neces- 

 sarily twist whatever is under the centre ; for the motion round the axis is 

 nearly lost, and, by that means, the implement, instead of rolling round in 

 the manner it does when drawn straight forward, comes round in the 

 same v.'ay as if it had no axis ; thus frequently tearing iip young grass 

 and displacing seeds in a manner that is not only always unsiglitly, but 

 often prejudicial ; whereas, by being shortened by their division, they re- 

 volve in different directions, and that inconvenience is avoided. In rolling- 

 land which has been ploughed into ridges, it is also evident that, when the 

 operation is performed lengthwise, the longer the roller is, the more unequal 

 will be its pressure upon the crown, or ujjon the sides of the ridge. It is 

 true that land should, in most cases, be ploughed across the I'idges ; but in 

 water meadows, which are sometimes slightly raised in the centre of the 

 panes, and in arable land that is intersected by very deep farrows, that can- 

 not be done. 



CONVEX ROLLERS 



are therefore occasionally employed to meet the latter difficulty, by rolling, 

 without crossing, the furrows of arable land. The centre part, or belly, 



* Survey of Surrey and the Neighbouring Counties, vol. i, p. 217. 



D 2 



