138 
Improved Kilns for hiriihuj Lime. 
A better form for this description of kiln is, in my opinion, 
one similar in section and size to the "Perpetual Kiln," making- 
use of a circular open grating-, cast in segments as a fire-grate, 
for one central furnace domed over to form the floor of the 
kiln, with brickwork 9 inches thick springing 15 inches above 
the fire-grate and rising 1 foot 9 inches. The furnace should be 
3 feet diameter at the top of the fire-grate ; and the dome or the 
floor should be pierced with radiating holes, 4^ inches by 3 inches, 
to allow the fire to pass through. 
Fig. 6. — Plan of Circular Intermittent Kiln ivitli central furnace. 
The bricks would be required to be made on purpose, and 
should all be laid heading. The kiln should be filled and packed 
in the same manner as that last mentioned, and covered over on 
the top with two courses of burnt bricks in a similar manner. 
I have never tried a kiln constructed in this manner ; but I 
feel sure that it would answer well, and I think it would save 
one-third of the fuel, as compared with the last mentioned kiln, 
besides burning the lime much more evenly. 
Both of the last described kilns may be roofed or domed over, 
but in both cases the expenditure would be very much greater, 
without, as far as I can see, any corresponding advantage ; and 
the labour of filling the kiln would be very much increased. 
If the kiln is built entirely into the side of a hill, it is 
necessar}' to construct a floor over the kiln pit to form an ap- 
proach to the hatchway ; and if this floor is roofed over it will 
form a dry and commodious lime store. 
Wood fuel may be used instead of coal in these kilns, and 
when used it is not necessary to have any fire-grate, as the wood 
fuel requires but very little draught. 
The advantages of this description of kiln may be stated 
to be : — 
