Mr Rose on an improved Glaze for Porcelain. 127 
sides. The ends of the rope-ladder should be fastened into the 
pavement by means of iron-staples. 
6. Account of an improved Glaze for Porcelain. By Mr John 
Rose *. 
The common glaze for porcelain and the finer kinds of earth- 
en-ware, contains glass of lead, which is extremely liable to com- 
bine with and degrade the more delicate colours, especially 
those obtained from preparations of chrome and of gold. This 
is particularly the case with those elaborate products which re- 
quire to be repeatedly heated or fired. 
The chief ingredient of Mr Rose’s glaze is pale flesh-red 
coloured feldspar of a somewhat compact texture, which forms 
veins in a slaty rock near the Welsh Pool in Montgomeryshire. 
When freed from all adhering pieces of slate and quartz, the 
feldspar is ground to a fine powder, and 27 parts of it are 
mixed with 18 of borax, 4 of Lynn sand, 3 of nitre, 3 of soda, 
and 3 of Cornwall china-clay. This mixture is melted into a 
frit, and ground to a fine powder, 3 parts of calcined borax 
being added previously to the grinding. 
This new glaze has been examined by competent artists in 
London appointed by the Society, and highly approved of. 
They found that, from being softer than that used by the French 
manufacturers, it incorporates more completely with the colours, 
and renders them perfectly firm ; whereas every artist knows 
that colours laid on French porcelain are extremely apt to chip 
off, crackle, and flake, if it is necessary to make them pass the 
fire a second time. 
7. Chinese Method of malting Sheet-Lead , and its Application 
to the malting of Zinc-Plates for Galvanic Experiments. 
The method of making sheet-lead employed by the Chinese 
has not, so far as we know, been described in this country. The 
following notice of it we owe to our ingenious friend and cor- 
respondent Mr Waddell, who, during his residence in China, 
obtained much information respecting the arts of that singular 
country. The operation is carried on by two men. One is seated 
* Abridged from the Transactions of the Society of Arts, vol. xxxviii. 42. 
