THE PLAIN 'ENGLISH' OF IT. 191 



nearly as possible inverted in its bed and I do not 

 think they will be long in setting the steam-engine 

 about its proper task, in the proper way. But their 

 attention is distracted, at present, from the end to 

 the means. They are taught to think that the plough 

 is a sine qua non that steam cultivation of necessity 

 implies steam-ploughing, and they are led to give up 

 the task in despair, because they are at fault upon 

 a false scent. 



' We have many rolling implements employed in 

 the field, but we have only one instance of a revolv- 

 ing implement. The clod-crusher and the Norwegian- 

 harrow roll ; the hay-tedding machine (one of the 

 best instruments ever invented) revolves. I use the 

 words somewhat arbitrarily, but the difference I 

 allude to is very important. The first are liable to 

 the evil of " clogging ; " because they derive their 

 axis-motion from the soil as they pass over and press 

 upon it. This action must not be confounded with 

 that of a machine which has its cause of revolution 

 within itself, independent, and acting upon the soil 

 as a circular saw acts upon a board, or the paddle- 

 wheel of a steamer upon the water. The teeth of a 

 saw clear themselves, by the centrifugal motion they 

 communicate to the particles they have detached from 



