C 342 ] 
of the Chimney, which made an obtufe Angle with 
the other 5 fo that they feemed to move up hiii, and 
againft their Weight. 
Surprifed at this, I thought the Cafe deferved a 
little farther Examination and propofed placing two 
Tubes horizontally, parallel to each other, and at 
right Angles to the Face of the Fire, to be Supporters 
to a third, which was to be placed upon them paral- 
lel to the Fire. We did fo, and with Pleafure ob- 
ferved the fupported Tube turn about its Axis> and 
move on towards the Fire in fucli a manner, as made 
me hill lefs inclined to think either cf the Motions 
owing to the Draught of the Fire, and certainly not 
to the whole Weight of the moving Tube; a fine 
Spirit-Level informing us, that the fupporting Tubes 
lean’d from the Fire 5 fo that the Motion was a lit- 
tle up-hill. 
This Succefs determined me, with Mr. Orme s 
Leave, to go on farther 3 and, furnifhing myfelf, from 
him, with Tubes of feveral Lengths and Thickneffes, 
I made feveral Trials 5 and found, that with a mo- 
derate Fire the Experiment fucceeded bed, when the 
fupported Tube was about twenty or two-and-twenty 
Inches long, the Diameter about one Tenth of an 
Inch, and had in each End a pretty ftrong Pin, fixed 
in Cork, for an Axe to roll with upon the fupport- 
ing Tubes ; which, to leffen the Contad, had nearly 
the fame Diameter with the moving one. Under 
thefe Circumftarices the Tube would begin to move 
at eighteen Inches Diftance from the Fire ; and con- 
tinue to do fo, with little Intervals, till it touched 
the Bars; and moved much in the fame manner, 
when a little Ball of Cork, an Inch or more in Dia- 
meter, 
