248 Description of a new Method of forming Crucibles. 
of soft pipe clay into the shape of the intended crucible, and laid 
it with its mouth downwards on a flat surface, and inclosed it 
with a eylinder of white-iron, distant about half an inch from the 
angular points of the crucible, and about an inch and a half 
higher than its bottom; then mixing the stucco with water, 
poured it into the eylinder. When the stucco was sufficiently set, 
I removed the white-iron, picked out the clay, and dried the 
mould ; I then squeezed soft clay into the mould, which on stand- 
ing a few minutes, easily came out again. It was inclosed in the 
cylinder, and stucco poured round it, which formed a second 
mould, continuing to do so until I had procured the number 
wanted. They were then all put into a stove, and eemagirtely 
- dried ready for use. 
In the preparation of the fire-clay for the cndlides I followed 
precisely the same process“ used at the potteries, by mixing it 
with a very large quantity of water, and putting the whole through 
a No. 9 silk searce. On allowing the whole to: stand. ‘a few hours, 
the clay subsided, and in pouring off the clear water, I procured 
the clay or slip of the consistence of thick cream. On weighing 
a gallon of it, I found the proportion of clay it contained, and 
added sand to the whole, in the proportion of seven of s: 
seventeen of clay; I then stirred and mixed the whole c 
‘when it was ready for use. I next took my moulds previously 
‘dried, and arranged them in parallel rows on a table, and suc- 
vessively filled them with the prepared slip. © By the ime I had 
- filled four or five dozen, I returned to the one first filled, and be- 
gan alternately to pour the slip out of them, leaving a small 
‘quantity unpoured out, which subsided, and gave the requisite 
‘thickness to the Barton In each of ie moulds so filled, a cru- 
‘eible is completely formed by the abstraction of the water of the 
‘slip, in contact with, and adjoining to, the porous substance of 
the stucco mould. The crucible will be either thicker or thinner 
in proportion to the time the slip has remained in it. Five or 
six dozen will not require more than fifteen minutes in being 
formed, The moulds with their contents are then removed toa 
stove, placed on their side and built one above the other. In 
a short time, from the contraction of the clay, the crucibles easily 
part from the moulds, and are removed by introducing the finger 
into them. The moulds are allowed to remain in their situation 
‘until the water they had absorbed is completely evaporated, when 
they are again ready for refilling, and will last for years. The 
crucibles remain in the stove until dry, after which they are 
‘burned in a kiln in the usual manner. 
The process is simple, and combines the Be, ntapes of form- 
ing them with great facility, and giving them the required shape, — 
which - 
