Improvements upon Fire Grates, Stoves, &c. 267 
der anfwerable to the curvature of the fpace between the 
back of the chimney and the lining above-mentioned, made 
in oné or more pieces, and moving in a circular groove, 
644, in or upon the hearth, which ferves to condué it into 
its place behind the grate, when the fire-place is wifhed to 
be left open, as before mentioned. The top of the front of 
the opening of the chimney O, Fig. 4, projects in a cir- 
cular form, or is furnifhed with an added projeétion, made 
of metal, marble, or any other fit material 3, but in either 
cafe the projection is furnifhed with a circular groove on its 
under furface, of the fame radius with the one in, or planted 
on the hearth, for the purpofe of receiving the upper part 
of the frame-work of the fence or fafeguard, which frame- 
work may be filled up with glafs, either plain or bent, and 
either colourlefs or. coloured, or ftained or painted with 
figures or defigns of any kind. By this means complete 
fafety is obtamed again{ft any fuch accidents as have been 
alluded to, while at the fame time the comfort arifing from 
the view of a cheerful fire is not prevented by the interpofi- 
tion of any opake body ; but for nurferies or the like, where 
convenience and fafety is more the obje&t than elegance or 
Juxury, the frame-work may be filled up with wire-work. 
The fence may be feen in its place at P. . 
Where either the glafs or the wire-work fence, or both of 
them, are meant to be applied to fquare or retangular chim- 
neys, without the trouble of giving them the femi-cylindrical 
form, the lining to receive the fence or fences may be intro- 
duced at the fides or jambs of fuch chimneys ; or the fence 
may be made to rife by means of pulleys into the wall above 
the opening, or flide fideways into the walls at the fides of the 
opening. 
Thefe improvements may be introduced together or fingly, 
and may be applied to many of the grates now in common 
ufe. 
Befides the advantages already pointed out as conneted 
with them, they poffefs alfo the following.—Any room or 
apartment may be heated by their means with a much 
fmaller quantity of fuel than by any other method yet in 
ufe: at the fame time the advantage of feeing the fire is not 
Mm 2 loft, 
