97

“ Laboratory No. 318. This clay only required 14 per cent of water for
tempering, owing to the presence of a large percentage of rather fine-grained
quartz sand. The plasticity and working qualities were low for this reason.

“The drying shrinkage was only 3 per cent.

“ The following results were obtained on burning:

Cone Fire shrinkage Absorption Colour
To. as %

01:0: 0 8 salmon
06 0 8 buff
Osi 0 8 ‘$

5 0 ff #
14 begins to soften : grey
18 fused

“ As this clay is too sandy to use alone, a mixture was made by adding 50
per cent of a fat clay (315) from a nearby locality. This gave a body with proper-
ties intermediate between the two extremes of a highly plastic clay with large
shrinkage, and a lean clay with low shrinkage, so that the results obtained in
working and burning were good. The air shrinkage was about 5 per cent. A
steel-hard, practically non-absorbent body was produced at cone 1.

“This mixture would probably be suitable for sewer-pipe,. or electrical
conduits.

“ Laboratory No. 314. This is a soft, grey clay, with good plasticity and
working qualities. Wares moulded from it will stand fast drying without
checking.

“ The drying shrinkage is 6 per cent.

“The following data were obtained on burning:

Cone Fire shrinkage Absorption Colour
Jo Jo
010 ' Ot 12 salmon

06 1°0: 9 s

03 273: 6 §
1 3°4 1 buff
5 4°6 0: grey
9 intact

14 softens

“This is a good material, the shrinkages are low, and it gives no trouble
on burning. It would be useful for the manufacture of face brick, fire-proofing,
electrical conduits or sewer-pipe............

“ Laboratory No. 317. Light grey clay, with slightly reddish tinge, requiring
only 17 per cent of water for tempering. It is rather stiff in working when wet;
the plasticity is good, and the clay is very smooth. The drying qualities were
not tested, but they are probably good, owing to the small amount of water
required to bring it to a working condition.

“The drying shrinkage is 5 per cent, and the following results were obtained
on burning:

Cone Fire shrinkage Absorption Colour
Jo Jo
010 0 10 salmon

06 0 10 ce

03 1 dé buff
1 1 6 Ke
5 2 3 grey
9 4 vitrified se

16 fused.