plough, but both thejshape 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 en- 

 gaged in the business, 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 ©f 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 moveable type, in its influence on the general condition of man- 

 kind. The impulse imparted to commerce by the introduction of the steam- 

 boat and the railroad is something marvellous. In 1770 the exports of Great 

 Britain amounted to $65,000,000; in 1870 to $1,220,000,000. The shipping 

 owned in England has increased from half a million, to seven million tons. The 

 amount insured — just think of this — the amount insured rose from $850,000,- 

 000 to six billions eight hundred millions. These figures are so vast that they 

 make but a slight impression upon the mind. The intellect is confused and be- 

 wildered, as when it seeks for the first time to grasp the duration of the geo- 

 logic periods, or the distance of the stars. With all this material development 

 there has been a corresponding intellectual development. "A large majority 

 of our most instructive books are the product of the last one hundred years. 

 Nearly all our prose romances, and most of our poetry, history and miscella- 

 neous literature belong to this same glorious epoch in origin and spirit. We 

 now write ten times as many books, and publish fifty times as many volumes 

 annually as they did in the last century. The United States turns out 2,000, 

 and Great Britain 4, 000 new books every year, and the other Aryan nations 

 probably bring the total figure up to 15,000, whereas before the middle of the 

 last century, the number was probably not more than 1500. Besides the 

 books, we have now 7,000 newspapers which are new, and in the aggregate 

 furnish as much material for reading, and contribute nearly as much to educa- 

 tion, as the books. But there is another point, interesting and of vital signifi- 

 cance to be noticed here. With this increase of material and intellectual 

 riches, there has been a corresponding increase in the numbers of this actived 

 energetic, and brilliant Aryan race. Within a hundred years it lias increase, 

 from 120 millions to 360 millions. This is something altogether remarkable. 

 Nothing of the kind has taken place before since the historical era began. Ttie 

 Roman empire had about 120 millions inhabitants, and the same territory after 

 the lapse of 18 hundred years had no more. Egypt 3,000 years ago, and Spain 

 and IV^iexico before the Spanish conquest, had more inhabitants than now. This 

 wonderful increase is due chiefly to the invention of steam. "Asa general 

 rule," says Hittell, "population has been nearly stationary; century after cen- 



