APPARATUS FOR BREAKING UP LOGS OF WOOD. 3$ 



Contrivance many years ago, when a relation of his ufed to 

 & ! mufe him (elf with fplitting the roots of trees, &c. in the com* 

 mon way. I have ufed the blafting-fcrew, for fo I ihall call it, 

 all the laft and preceding winter, with the greateir. fuccefs> 

 and have gained many loads of fuel, which otherwife would 

 have been fufFered to rot, as the expehfe and labour in clearing 

 the roots in the ordinary Way renders the fuel fo procured too 

 expensive ; and fince I have had the fcrew, I have obferved 

 fome hundreds of roots in a rotting ftate in other places, from 

 the want of knowing that there was fuch a contrivance as the 

 fcrew. I think you would ferve the public in no fmall degree, 

 by divifing fome method of making its ufe known to the workL 



When I was at Overton, fome pieces of very tough, knotty, 

 clofe-grained oak were picked from the timber-heap, for the 

 ufe of the Gregory lead-mine, by Sir Jofeph Banks's direction, 

 and the fcrew fevered fome pieees four or five feet in length, 

 and nine or ten in diameter, throwing Ihem fome feet afunder, 

 to the furprife of the miners, who were affembled on the mine* 

 bank. Sir Jofeph took the fcrew with him to Revefby-Abbey, 

 in Lincolnshire, where, I underftand, he had fome large roots, 

 that had lain by many years as ufelefs ; and I dare fay he wilt , 



give you a good account, and bear tefiimony to the utility of the 

 invention. We have ufed it without a tingle accident ; but my 

 neighbour, Lord Kirkwall, having procured one to be made 

 by that which I had from you, one or his fervants, in his Lord* 

 (hip's abfence, I prefume, put too much powder into the hole, 

 and the fcrew was blown as high as a one- pair pf-ftairs window, 

 and patfed through it into an apartment where a perfon then 

 happened to be, but without any farther mifchief than the lots 

 of a pane of glafs. Any one who ufes the inftrument will foon 

 Jearn what depth of fcrew will be fufficient to fplit any root in, 

 proportion to its ftrength, taking care that the fcrew has fuf- 

 ficient hold to refill: the force of the gunpowder, before the root 

 is cleft. I think much powder may be laved by ufing a cotton 

 match, impregnated by a folution of faltpetre, or any of the 

 combuftible matters generally made ufe of in fire-w r orks ; and 

 by the ufe of the cotton the hole through the fcrew may be 

 leflened, which will add to the action of the confined powder, 

 though a ftraw filled with powder, in the manner in which the 

 miners ufe it, anfwers very well. Should any one be timid in 

 ufing the fcrew, a chain or rope may eafily be attached to the 

 fcrew, and that fixed to any log, or fattened to a fiake driven 



Vol, V.— May. D into 





