Book III. 



IMPROVING WOODY WASTES. 



675 



answers all the purposes of the firmest ramming or wadding. It has been used for 

 upwards of ten years at Lord Elgin's extensive mining operations at Charlestown in 

 Fifeshire, and also in removing immense bodies of rock from the Calton hill at Edinburgh, 

 by Stevenson, an eminent engineer, whose article on the subject of blasting, in The 

 Supplement to the Encyc. Brit., deserves the attention of such as use the process in work- 

 ing quarries or clearing rocky or stoney grounds. 



Sect. III. Of improving Woody JVastes or Wealds. 



4172. With surfaces partiall?/ covered with bushes and stumjys of trees, ferns, &c., the 

 obvious improvement is to grub them up, and apply the land to cultivation according 

 to its nature. 



4173. The growth of large trees is a sign that the soil is naturally fertile. It must also 

 have been enriched by the quantity of leaves which in the course of ages have fallen and 

 rotted upon the surface. Such are the beneficial effects of this process, that after the 

 trees have been cut down, the soil has often been kept under crops of grain for a number 

 of years without interruption, or any addition of manure. Land thus treated, however, 

 ultimately becomes so much reduced, by great exhaustion, that it will not bear a crop 

 worth the expense of seed and labor. (Communicatio7is tothe Board of Agriculture, vol. ii. 

 p. 257.) It is evident, however, that this deterioration entirely proceeds from the 

 improvident management previously adopted. In reclaiming such wastes, the branches 

 of trees that are felled are generally collected and burnt ; and the ashes are either in whole 

 or in part, spread on the ground, by which the fertility of the soil is excited. Indeed, 

 where there is no demand for timber on the spot, nor the means of conveyance to any 

 advantageous market, the whole wood is burnt, and the ashes applied as manure. 



41 74. Much coppice land has been grubbed up in various parts of England, and brought 

 into tillage. Sometimes woods are grubbed for pasture merely. In that case the ground 

 should be as little broken as possible, because the surface of the land, owing to the dead 

 wood and leaves rotting time out of mind upon it, is much better than the mould below. 

 It soon gets into good pasture as grass land, without sowing any seed. [Communications 

 to the Board of Agriculture, vol. iv. p. 42.) But by far the most eligible mode of con- 

 verting wood land into arable, is merely to cut down the trees, and to leave the land in a 

 state of grass until the roots have decayed, cutting down with the scythe from time to 

 time any young shoots that may arise. The roots in this way, instead of being a cause 

 of anxiety and expense, as they generally are, become a source of improvement ; and a 

 grassy surface is prepared for the operation of sod -burning. (Marshal's Yorkshire, vol. i. 

 p. 316.) 



4175. Natural woods and plantations have been successfully grubbed up in Scotland. 

 In the lower Torwood in Stirlingshire, many acres of natural coppice were cleared ; and 

 the land is now become as valuable as any in the neighborhood. (^Stirlingshire Report, 

 p. 213.) On the banks of the Clyde and the Avon, coppices have been cut down, and 

 after being drained, cultivated, and manured, the land has been converted into productive 

 orchards. In Perthshire.also, several thousand acres of plantations have been rooted out, 

 the soil subjected to the plough, converted into good arable land, and profitably employed 

 in tillage. (Perthshire Report, p. 329.) 



4176. For jmlling up or rending asunder the roots of large trees, various machines and 

 contrivances have been invented. Clearing away the earth and splitting with wedges is the 

 usual mode ; but blasting is also, as in the case of rocks and stones, occasionally resorted 

 to. For this purpose a new instrument, 

 called the blasting-screw (Jig- 541.) f 

 has been lately applied with consider- \ 

 able success to the rending or splitting 

 of large trees and logs of timber. It 

 consists of a screw (a), an auger (6, c) , 

 and charging-piece (rf). The screw 

 is wrought into an auger-hole, bored 

 in the centre of the timber ; here the 

 charge of pow^ler is inserted, and the 

 orifice of the hole in the log is then 

 shut up or closed with the screw, when 

 a match or piece of cord, prepared with 

 saltpetre, is introduced into a small 

 hole (a), left in the screw for this purpose, by which the i^ojvder is ignited. The appli- 

 cation of this screw to the purposes of blasting is not very obviously necessary, because, 

 from what we have seen (4171.) it would appear that the auger-hole being charged with 

 powder and sand, would answer every purpose. One great objection to the process of 

 blasting applied to the rending of timber is, the irregular and uncertain direction of the 

 fracture, by which great waste is sometimes occasioned. It may, however, be necessary 



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