226 ' On the Manuring of Grass Land. 



towns, in fields which did not appear to have been ploughed, he had often been 

 surprised by finding pieces of pottery and bones some inches below the turf. 

 On the mountains of Chile he had been perplexed by noticing elevated marine 

 shells covered by earth, in situations where rain could not have washed it on 

 them. 



" The explanation of these circumstances which occurred to Mr. Wedgwood, 

 although it may at first appear trivial, the author does not doubt is the correct 

 one, viz., that the whole is due to the digestive process by which the common 

 earthworm is -supported. On carefully examining between the blades of grass 

 in the fields above described, the author found that there was scarcely a space 

 of two inches square without a little heap of the cylindrical castings of worms. 

 It is well known that worms swallow earthy matter, and that, having separated 

 the serviceable portion, they eject at the mouth of their burrows the remainder 

 in little intestine-shaped heaps. The worm is unable to swallow coarse 

 particles ; and as it would naturally avoid pure lime, the fine earth lying 

 beneath either the cinders and burnt marl, or the powdered lime, would by a 

 slow process be removed and thrown up to the surface. This supposition is 

 not imaginary, for in the field in which the cinders had been spread out only 

 half a year before, Mr. Darwin actually saw the castings of the worms heaped 

 on the smaller fragments. Nor is the agency so trivial as it at first might be 

 thought, the great number of earthworms (as every one must be aware who 

 has ever dug in a grass field) making up for the insignificant quantity of work 

 which each performs,"* 



Johnston quotes from the Carlisle Journal an instance illustra- 

 tive of the quantity of worms in grass land. A bowling-green at 

 Penrith (45 yards by 32) was watered with a solution of corrosive 

 sublimate, after which eleven stones of worms were gathered, and 

 four years before twenty stones. Here is a cause adequate to the 

 effect produced. 



To determine how far decomposed grass really contributes to 

 the fine soil of pastures, I made the following experiment : — 



Two samples of soil were taken from Heath Common, opposite 

 Heath Hall, the residence of Colonel Smyth, M.P,, the one at 

 the depth of three-quarters of an inch, and the other at the depth 

 of three and a half inches. Both specimens contained a good 

 many roots of growing grass, but that taken nearest the turf 

 contained considerably more than the other. Both samples were 

 carefully dried for the same time at the same temperature, not 

 exceeding 200° Fahr, ; and after having the larger roots pic ked 

 out, both were burnt with the usual precautions and weighed. 

 The sample taken at three-quarters of an inch lost 10"6 per cent,, 

 vvliile the sample from a depth of three and a half inches lost but 

 9'5 per cent., showing I'l per cent, more organic matter in that 

 wliich was taken near the turf. It seemed unnecessary to make 

 another experiment to dispose of the notion of "vegetable soil" 

 beneath meadows and pastures. Here is a plot of land which 

 has probably never been wrought by man, but has laid in a state 

 of grass or other natural crop ever since the Deluge. It bears a 

 short, green, nutritious pasture upon which cattle are reported to 



* ' Penny Cyclopaedia,' art. " Lumbricus." 



