On the Manuring of Grass Land. 227 



thrive well ; and yet 100 lbs. of it taken close to the turf, and 

 100 lbs. taken at a deptli wliich appeared natural soil, with a few 

 roots in it, differ by but one pound and a tenth of organic matter. 



The common consists of useful turnip soil upon the sandstone 

 of the coal-measures. 



That worms are the agents which produce this fine earth in 

 our grass-fields, is put beyond question by an instance in which 

 their operations are unusually evident. Some years ago a 

 gentleman near Thirsk, in Yorkshire, is said to have introduced 

 from the Continent a worm unknown in England, having a blue 

 head and far exceeding in size the largest dew-worms. At first 

 the worms were confined, to a small plot upon his own estate, 

 but now their operations may be traced in three different pro- 

 perties over more than 200 acres. One of the gentlemen, Mr. 

 Pecket, of Carlton Hasthwaite, who is troubled with them — for 

 they are regarded as a plague — informs me that it is no un- 

 frequent occurrence to sink up to the ankle in wormcasts in a 

 grass-field. He says that the casts are often four inches high, 

 and that they are quite as great a nuisance as moles. Indeed, 

 their labours are as evident upon the surface as those of that 

 animal. I have not yet had an opportunity to go and examine 

 the subject, but hope to do so and to publish the result. 



Meanwhile Mr. Pecket has obligingly sent me some sections 

 of turf and soil, and one of these strikingly corroborates Mr. 

 Darwin's account of what he saw in Staffordshire. The section 

 was taken from a field in which the worm labours have ceased, 

 and was labelled " no worm for many years." Just under the sod 

 and parallel with it was a layer of coal-ashes, as they are gene- 

 rally called, but, in reality, fine cinders. This layer was almost 

 continuous, and was probably the cause of the worms ultimately 

 forsaking the field, owing to the difficulty of ascending and de- 

 scending. I burnt a sample of this (after picking out all the 

 larger fragments), taken from the depth of an inch, and found it 

 to contain 148 per cent, of combustible matter, chiefly, of course, 

 fine cinders. A portion from the same section taken four inches 

 below the surface contained but 4'2 per cent. 



This dressing with fine cinders must certainly be condemned 

 on grass, for being almost indestructible they must impede the 

 action of the grass roots and the culture of the land by insects. 

 Soot may be objected to upon the same principle. Its large pro- 

 portion of carbon must remain for many ages a useless encum- 

 brance to the soil, and it therefore appears prudent to use it cau- 

 tiously, and with considerable intervals between the applications. 



In this instance the effects are noticed simply because the 

 larger size of the agents renders their labours more easily ob- 

 servable, but it is manifest that what takes place here may be 

 found everywhere else if properly sought, and that all the differ- 



