( &9 ) 
ocher more fix’d Streams to which ic always kept icfelf 
parallel. 
1 am perfuaded that the Iare Appearance was of 
the lame Kind with this, which, i have now been de- 
lcribing. For let A B, reprefent the plane of the Ho- 
rizon, C the place of the Spectator, E F, a fund of 
Vapours or Exhalations at a coniiderable height above 
us, diffus’d every way into a large and fpacious Plane, 
parallel to the Horizon. This Fund of mixc matter 
by Fermentation will emit Streams from ic (elf, fuch 
as EG, F H, o c • which, if the Wind be perfidfly 
dill, will a(cend perpendicularly upwards ; if it be 
boifferous and irregular, they will be blended and 
confounded together; but if it be very gentle and u- 
niform, as it was at the time of our Appearance, they 
will be inclined towards the point of the Horizon, 
which is oppofite to chat from which the Wind blow's! 
Now if A D 13 reprefent the concave of the Heavens 
and a Line, C D, be drawn parallel to the Columns 
E G, F G, (z>c. cis certain by the Rules of Perfpedfive, 
that thefe Columns will appear upon that concave to 
converge all around towards the Point D : Thus the 
Column, E G, will feem to a rife from the Point e, to 
afeend up to g, and to take up the Space e g ;and- 
in like manner the Arch f h will be the Projedion 
of the Column F H. From hence it is evident that 
the reafon why the triangular Streams afcended at fird 
only from the Northern Parts of the Heavens was 
this : The Fund of Matter, E F, w>as not yet arriv’d 
by its motion to the Line C D. After ic had pafs’d 
that Line, it is plain they muft appear to afeend 
from all Quarters. ^ A great number of Columns be- 
ing therefore difposd to emit Light, at the (ame time, 
caus’d that perfett Canopy, which, I deferibed above. 
The realon why that Canopy defeended lower in the 
North, than in the South, was this.* The ftiining Co- 
lumns 
