A RAINY DAY. 207 



between the imbedded stones of the road, the water- 

 drops gradually collect to form rills. Note again, 

 how the little rills unite to make streams. See how 

 rill joins rill, until quite a respectable current, as to 

 size, runs into the channel of the overflowing gutter. 

 The gutter itself is made and formed by such rills. 

 The road is, indeed, the " catchment basin " of the 

 rivers, which its gutters represent. If you were to 

 draw a map of that road, its rills, rivulets, and gutters, 

 you would imitate clearly and closely the chart of 

 every big river you know. For, in truth, the biggest 

 river differs only in kind, and not in degree, from the 

 rill on the road. It is fed and nurtured by its streams, 

 exactly as that gutter is fed before your eyes to-day. 

 There is a whole lesson in physical geology spread out 

 before us this rainy day, in the shape of that soaking 

 roadway ; and from small things at home to great 

 things abroad, is but a step which the scientific use 

 of the imagination will bridge over easily enough. 



Look again at the rills in the road, and note the 

 work they are accomplishing in the small arena they 

 occupy. For see, how the road is washed bare by the 

 rain, its dust-particles having been swept away to the 

 gutters at the sides. This is the first work of the 

 rill and the river alike. Each cuts out a channel for 

 itself the river through the land, on a big scale ; the 

 rill between the stones, on a small one. Again, each 

 is a carrier and transporter of the debris which it de- 

 taches from the land. The sodden and dirty water of 

 the gutters is the result of the sweeping away of the 

 things of the earth by the rills. If you take up a 

 tumbler of that gutter-water, and allow its sediment 

 to settle, you will find it is one-half mud. Multiply 

 your one tumbler-full of such debris by the thousands 



