On the Theory and Practice of Water -Meadows. 463 



seen a stream issuing near the top of a steep moor-side, down 

 which, in its descent, it draws a straight line of vivid verdure, visible 

 at a mile's distance against the black heath. Not but where a 

 deposit does take place, it is most beneficial. However dull the 

 stream when it enters, after trickling through the grass it issues 

 clear. So that, as I have heard, at Tempsford, a sluggish mill- 

 stream previously thick, allows you, after it has passed over the 

 meadows, to detect the pike basking six feet deep under its surface. 

 The matter thus left behind is proved to be fertilizing by the 

 superior efficacy of the first floods ; but where are we to seek the 

 cause of the clear water's action ? An experienced maker of water- 

 meadows examining a spring, told me, after feeling the water by 

 holding some of it in the palm of his hand, that it must be good 

 for watering : all streams, it should be remembered, are not equally 

 good, some are even injurious. When asked the ground of his 

 opinion, he answered, that it felt warm and oily. To confine our- 

 selves for the present to the former quality warmth — -springs, issuing 

 as they do from different depths, and partaking therefore more or 

 less largely of the earth's central heat, vary much in their tem- 

 perature, though most of them, perhaps all, are warmer than the 

 earth's surface in winter. But the warmer the spring the better 

 it is considered for water-meadows in Devonshire, where springs 

 are much used for the purpose ; elsewhere it is chiefly small 

 rivers which are so employed. We must suppose, then, that the 

 water acts in irrigation partly by the warmth it communicates to 

 the soil. A curious proof of this view is afforded by the following 

 circumstance : — There is a stream in Devonshire which was use- 

 less in irrigation until it reached a station of the Atmospheric 

 Railway, where warm water escaping into it from the steam- 

 engine, rendered it at that point, for the first time, heneficial to 

 the land it passed over. In that county where the warmth of 

 springs is much studied on this very account, a wide difference of 

 temperature is found in springs issuing from the same hill-side. 

 Some springs freeze at once in a hard frost, a thick basin of ice 

 forming around the well-head. Another spring a few hundred 

 yards off may be seen on a frosty morning steaming like a caul- 

 dron. It not only does not freeze at the source, but its waters 

 will continue to pass in a fluid state over meadows during a frost. 

 The warm spring is selected for irrigation : the cold one is kept 

 aloof. It is also supposed that the south sides of hills yield warmer 

 streams than the north sides, and these southern streams are there- 

 fore preferred for meadows. We may safely conclude then, I think, 

 though I have never seen it so stated in any agricultural work,* 



* Since the above was written I find that, though recent agricultural works deny 

 the efficacy of warmth in irrigation, Sir H. Davy, himself a west-countryman, asserts 

 it in his Agricultural Chemistry. 



