248 MACHINE rOR SWEEPING CHIMNIES. 



with as good effe6l as need be, barring the hazard of fettlng 

 fire to the foot; and indeed, when a chimney has accidentally 

 taken fire, it is the beft and moft expeditious mode of putting 

 it out, at leaft of bringing the foot into a fituation by which it 

 may be extinguithed. 

 Eftimate •£ the I have faid that the vefTel contains nearly three cylindrical 



velocity of the feet, and we cannot crowd three atmofpheres of air into it, in 

 extei\ded air, and , . r 



its ejffea in the which cafe there will be 42 lbs. per inch fquare at round nura- 

 chimneyj toge- bers, preffing againft the charge in the tube, or rather againll 



ther with that of , , , , , . r • , ,- . . 



the gravel. the valve, the tube being 2^ inch diameter, which amounts to 



168 lbs. for the whole area. This air will all be difcharged in 

 one fecond, the mean velocity of which may be fairly reckoned 

 at 60 feet, in that time having impetus in itfelf fufficient to carry 

 away any foot of confequence in a chimney of 100 feet high ; 

 but when we take into the account the charge of gravel, being 

 alternately incident and reflected on all fides of the chimney, 

 we need not fear to affirm that it is perfectly applicable to its 

 intention. 

 Additional tubes j^ render it as univerfal as poffible, there muft be another 

 chimiiies. tube, to be occafionally ufed, when the fide of the chimney 



near the fire place is gathered over in order to bring the throat 

 of the flue over the fire, as at Fig. II. from a to b, or it ftiould 

 be in feveral pieces, to conform to the height of this gathering, 

 and in this cafe the charge muft be at the upper fiflure at b, 

 and the pipe flayed as perpendicularly as can be conveniently 

 done; for which purpofe there is a piece made to fix on the 

 pipe, having two flems, as Fig. III. which if put in the bear- 

 ing fide of the pipe, will keep it upright and in the crater of 

 , , the flue. The machine thus conftru6ted is to be laid on a little 

 truck, and tranfported from houfe to houfe, with a gallon of 

 gravel to begin with; becaufe until it has obtained the good 

 opinion of the public, it would not be neceflfary to attempt 

 fuch regulations as would afterwards be deemed requifite to 

 facilitate the operation. 

 Trial at the This poor thing, brought forth under other difadvantages 



Sodet "If Arts befides its Angularity, was conduaed to the Adelphi, to un- 

 in the Adelphi. dergo an eventful trial, in competition with fome others, who 

 had no fuch fingularity to be imputed to them; they being all 

 defcendents of the flock of one family, the reraoteft relation 

 between each not being more diftant than coufin-german. — 

 Other machines Qne of them however poflefled great originality and ingenuity 

 alfj exhibited ' in 



Ifhcre. 



