GROWTH OF AGRICULTURAL SOCIETIES. 21 



coach line, which had lately been started and was ruining 

 their business. In 1760, England began building canals, and 

 now six thousand miles have been constructed by the AryaDS, 

 at a cost of $500,000,000. The shipping of Christendom 

 has risen from fifteen hundred thousand to fifteen millions of 

 tons. Railroads, one hundred and forty thousand miles in 

 length, have been constructed at a cost of $2,000,000,000. 

 So also the gain in the materials for commerce has been 

 immense. Steam-engines furnish a power estimated to be 

 equal to that of three hundred million workingmen, and the 

 saving of labor by other machines is probably almost as 

 much. The annual consumption of iron has increased from 

 two hundred thousand to twelve million tons. Our houses, 

 our tools, our clothing, our food, our trades, and our pro- 

 fessions, are different in many important points. Farmers 

 have thrown aside the wooden plough within a hundred years. 

 The wooden mould-board was excellent as compared with the 

 barbaric plough which had no mould-board, and did not throw 

 a furrow to one side, but merely scratched the ground, mak- 

 ing a ridge on each side of the plough-point. While oak was 

 the material, the farmer usually hewed or chopped out his 

 own board, aud fastened it on his plough ; but both the shape 

 and the adjustment were bad, and the surface, from the nature 

 of the material, would never "scour" well in the moist earth. 

 The iron mould-board was first appreciated and perfected, if 

 it was not invented, in the United States. The superiority 

 of the iron plough made a vast saving in friction ; the furrow 

 was turned over more regularly ; the weeds were killed more 

 thoroughly ; the pulverization was better ; and the working 

 capacity of the ploughman, and the productive capacity of 

 the soil, were each nearly, if not quite, doubled ; so that now 

 France, with a smaller number of men engaged [ n the busi- 

 ness, yields three times as much wheat at an average harvest 

 as it did about 1770. 



Now, since the farmers are the largest class of producers, 

 and the basis of national prosperity, and since ploughing is 

 the most important part of their labor, the invention of the 

 iron mould-board deserves to be considered one of the 

 greatest contributions to modern civilization, ranking next to 

 the steam-engine and to movable type, in its influence on the 



