On Draining. 



515 



many of our towns ; and in point of first cost I am persuaded that, 

 where practicable at all, the plan indicated may be applied at one 

 quarter the sum expended upon many existing works. 



Let me now direct your attention to some of those meteorolo- 

 gical effects which, without pretending to any very intimate know- 

 ledge of that interesting science, I nevertheless believe exercise 

 an important influence in promoting the efficiency of drainage, as 

 well as that completeness in that operation will in its turn have 

 an equally observable effect over meteorological causes them- 

 selves. It is very common to speak of und rained land as being 

 cold, and a more significant designation could hardly be given, 

 for it is literally so, and that at a time when, for the purposes of 

 vegetation, it ought to be the warmest. The following observa- 

 tions on evaporation and filtration (for which w T e are indebted to 

 the patient and carefully conducted experiments of my relation, 

 Mr. Charles Charnock, of Holmfield House, near Ferrybridge) 

 present some curious facts for consideration, demonstrating the 

 cause of, and suggesting the remedy for, this baneful coldness. 

 (See Table in next page.) 



In the first place, it is observable how much greater is the 

 amount of evaporation from water than from land, and how near, 

 as shown by columns 2 and 5, the evaporation from wet land is to 

 that from water itself — hence the w r etter the land the greater the 

 evaporation, and, as the w T ell-known consequence, the greater its 

 excess of coldness. We have a familiar illustration of Nature's 

 process in this particular, in the method often adopted to cool 

 our wine on a hot summer's day, by wrapping a w r et napkin round 

 the bottle and exposing it to the full sun : as the moisture from 

 the napkin is evaporated, the temperature of the wine declines to 

 almost freezing-point. The school-boy's experiment of producing 

 ice before a fire, by incasing the vessel in wet flannel and adding 

 a portion of salt to the water, is a similar example, with this addi- 

 tional lesson to the farmer — that to apply certain limes to wet 

 land is only increasing the evil. 



You will then, in the second place, notice how much less the 

 evaporation is in the shade than in the sun, and consequently that 

 wet land must be the w r armest w T hen there is the least sun. From 

 which cause no doubt arises that too vigorous growth of young 

 wheat, so often observable on such land in the winter and spring 

 months, which never fails to produce serious injury to the crop in 

 all its subsequent stages. And, thirdly, you will remark how com- 

 paratively small a proportion of the rain which falls is sho vn to 

 be carried off by filtration. Taking the average of the five years' 

 experiments, it will be seen that only 4"82 inches, out of 24*60 

 inches of rain, passed through the land to the depth of three feet. 

 We might, therefore, be led at the first glance to infer that land 

 in general stands less in need of drainage, or may be drained by 



