745 
METALS. 
where it is allowed to settle for about an hour; the glass 
that settles in these tubs are sold by the name of farbe, or 
colour. The water is run off into other tubs, where it 
stands until quite clear ; the smalt collected in these is cal 
led eschel, or ashes. 
All of these sediments are washed over again, sorted into 
various qualities, and dried on slabs, either in a stove, or in 
sheds, with a free current of air. The cakes thus produced 
are crushed, either between cylinders, or by rakes, turned 
by water, or by ordinary mill stones ; or lastly, between 
two planks moved contrary ways. After which, they are 
sifted or bolted. 100 Cwt. of blue glass yield about 60 Cwt. 
of colour, or 70 Cwt. of ashes. 
The strewing smalt is used in painting, and the others in 
tinging linen and paper of a blueish colour. 
Speiss. 
Speiss is a secondary product obtained in making smalt, 
separating from the glass during its fusion, and settling at 
the bottom of the pots. 
It is a mixture of cobalt, nickel, iron, arsenic, bismuth, 
to which is sometimes added silver. 
When it is rich in cobalt, it is used over again in the 
making of zaffre; and when rich in bismuth, it is used to 
obtain that metal. 
Speiss is also the material from whence the experimental 
chemists generally obtain nickel. 
PLATINUM. 
This metal, which in the state it is usually obtained, 
alloyed with palladium and rhodium, joins the hardness of 
iron to the resistance of most chemical agents possessed by 
gold, is lately come into much use. 
It is obtained from the ore brought from Spanish Ame 
rica, by the name of platina, the diminutive of plata, silver 
and which is a kind of metallic sand. The platina is dis 
solved by the help of heat, in eight times its weight of 
a mixture of two parts of muriatic acid, at 22 deg. Baumé, 
and one of nitric acid, at 34 deg. Baumé. When the acid 
ceases to act, it is to be decanted, and fresh acid poured on 
the residuum, until all is taken up that the acid will dis 
solve, which generally requires four parcels of the acid. 
By this means, the iridium and osmium in platina is left in 
the residuum. 
The acid solution is then evaporated until it crystallizes