222 TILLERS OF THE GROUND CHAP. 



learn also to take from the dreary deserts of Chile, 

 and from the desolate, uninhabited islands of the 

 Pacific, the substances which will bring fertility to 

 his exhausted lands. He is learning now to utilise 

 modern chemistry and modern electricity to make 

 nitrogenous manures from the air itself. 



In tracing in this way the development of the 

 gardener and farmer of to-day from the first tillers 

 of the ground, we have every now and then stopped 

 to mention certain great names, the names of the 

 men who have stood out from among their fellows, 

 who mark the great periods of change in thought 

 or in methods. But even the shortened story as 

 we have read it here shows us one fact, a fact 

 which would have been clearer if the story had 

 been told in full. This is that the great men are 

 after all only the milestones which mark the fact 

 that a certain point in the journey has been 

 reached. The great men make progress visible, 

 but this progress would not have been possible if 

 it had not been for the work of the unnoticed 

 toilers, who smoothed the path for the labour of 

 the others. 



This is one of the reasons why it is well for us 

 to know the story of the development not of one 

 form of knowledge only, but of many that we 

 may learn that progress in knowledge, like progress 

 in walking along a road, comes from a great 



