Mr Cadell on the Manufacture of Mosaic at Rome. 349 
for these details we must refer to the work itself, confining our- 
selves to the extracts which explain the Manufactory of Mosaic. 
The manufactory of Mosaic pictures belonging to the Pope 
is in a large building to the south of St Peter’s. 
Enamels. — The building in which the establishment is si- 
tuated is large, and contains a collection of enamels drawn into 
the form of sticks. These are arranged, according to their co- 
lours, in an extensive suite of rooms. The number of shades of 
colour is 17,000. 
The enamel, consisting of glass mixed with metallic colour- 
ing matter, is heated for eight days in a glass-house, each colour 
in a separate pot. The melted enamel is taken out with an 
iron spoon, and poured on a polished marble placed horizontal- 
ly ; and another flat marble slab is laid upon the surface of the 
melted enamel, so that the enamel cools into the form of a round 
cake, of the thickness of /^ths of an English inch. 
In order to divide the cake into ^mailer pieces, the cake is 
placed on a sharp steel anvil, called Tagliulo, which has the edge 
uppermost, and a stroke of an edged hammer is given on the 
upper surface of the cake ; the cake is thus divided into long pa- 
rallelopipeds, or prisms, whose base is /^ths of an inch square; 
and these parallelepipeds are again divided across their length 
by the tagliulo and hammer into pieces of the length of /oths 
of an inch, to be used in the mosaic pictures. Sometimes the 
cakes are made thicker, and the pieces larger. 
For smaller pictures, the enamel, whilst fused, is drawn into 
long parallelopipeds, or quadrangular sticks ; and these are di- 
vided across by the tagliulo and hammer, or by a file ; some- 
times also these pieces are divided by a saw without teeth, con- 
sisting of a copper blade and emery ; and the pieces are some- 
times polished on a horizontal wheel of lead with emery. 
Gilded mosaic informed by applying the gold leaf on the hot 
surface of a brown enamel, immediately after the enamel is taken 
from the furnace ; the whole is put into the furnace again for a 
short time, and when it is taken out the gold is firmly fixed on 
the surface. In the gilded enamel used in mosaic at Rome, 
there is a thin coat of transparent glass over the gold. 
Ancient Enamel. — The ancient Romans, besides the enamel 
for mosaic, made other works in enamel. Winklemann men- 
