MACHINE FOR SWEEPING CHIMNIES. 249 



in the defign. It confifted of a congeries of bruihes, which in Bruihes. 

 preparation for a6tion were collapfed by their conftru6tion fo 

 as to admit of being thruft up the chimney with very little re- 

 fiftance, and when it had gained the top, on pulling a firing, 

 it expanded tothedimentions of the chimney, and brought the 

 foot down before it; but from want of a mechanical attention 

 to its conftru6lion, fome parts being too ftrong, and fome too 

 flight, it broke in the firft experiment. 



Another (very elegant inftrument) was prefented to the A finglebruft. 

 committee, confifting of a large brufli, fuch as I have feen in 

 fome churches to fweep down the cobwebs, with a feraper at- 

 tached to it; lengthened to the height of the chimney by a 

 feries of whalebone rods, whipped together as in the conftruc- 

 tion of waggoners* whips, very accurately jointed to each other. 

 Indeed this was eflential and common to them all, except one; 

 and that was a brufh, not to be fent up the chimney, but down 

 it, by getting on the top of the houfe, and putting it into the 

 chimney, and fo letting it fall to the bottom. However, it Notion that the 

 was faid, they would all do very well but mine, as a machine frf„°t'eronly to 

 like that was adopted to a redilinear flue only ; whereas theirs a ftralt flue, 

 had fo many joints and other properties to conform to a curva- 

 ture, that they would be fure to go through a crooked flue as j»mb iikai 

 well as a ftrait one. 



When the late Do6lor Johnfon had any thing advanced to The fame 

 him of the marvellous kind, his way of hefitation to admit it, °^"'^^* 

 was by faying " It may be very true, but it is impoflible." — 

 So I fay with refped to the difpofition of thefe rods, when (et 

 in competition with a volume of air going at the rate of fifty 

 feet in a fecond from the lower part of the chimney to the top. 

 What is there to flop it? What is there to pre vent its conform- 

 ity to the curvature or ano^/es, if you will? 



The manner in which thefe bruflies a6l, let their conftru6lion To hloto down 

 be what it may, is by ftriking off" the foot. What does a boy ^nzJZ^lsto 

 within the flue with the brufli in his hand? To be fure iweep- Jweep it down, 

 ing is the moft appropriate term for what he does; but then, 

 unlefs, we attend to the peculiarity of the adion, and confi- 

 der how far it is poflible to effe<5l that fweeping by another 

 mode of action, we fliall not get any further than the boy in 

 the flue. But is it not as eafy to conceive of a quantity of air 

 being put into aftion along a road or a ftreet, fo as to fweep 

 f way the dufl before it ? No; you will fay, it blows it along; 

 k but 



