[ 3^9 1 



with great expence and inconvenience, as the whole 

 manufacture mud have been interrupted for fome 

 time, and part of the mill-houfe mud have been 

 taken down. Being apprized of this intention, I 

 advifed the method here recommended. Accord- 

 ingly two flat bars were procured from a fcrap 

 forge, of zi inches by full 3-8ths of an inch, and 

 their ends furnifhed wirh icrew-pins of I' inch, 

 with fquare threads: the bars were then hollowed 

 on the under fide with a large fwage, in order to 

 make the edges lie clofe to the (haft. This done, 

 they were annealed and put to a large vice, and 

 twitted with a hand-hook, iuch as the anvil-fmiths 

 ufe; fo that one end had made a little more than a 

 revolution, after which a few blows of the hammer 

 (and which requires not fo much (kill as may be 

 imagined) formed them into a fpiral, fitted to a 

 cylinder of 12 inches diameter. They were then 

 carried to the mill at the diftance of five mibs, 

 and after the blocks were fitted to receive their 

 ends, were put on with the greateft facility. 



It may be neccflary to obferve, that the diflant 

 gearing of the mill was trigged, while the water- 

 wheel was turned back in order to twift the (haft 

 the reverfe way of its going; by which means the 

 fpir.ils bound clofer than could poflibly be by fcrew- 

 ing only, I (hould add, alfo, that fome blows of a 

 X 2 hammer, 



