210 ZINC. 
drops or globules, into a quantity of charcoal placed at 
the bottom to receive it. These globules are afterwards 
again melted, to run the metal into a mass. 
When exposed to the air, the surface of zinc is soon 
tarnished, but it scarcely undergoes any other change. 
It has a certain degree of ductility. When heated a 
little above 21,8 of Fahrenheit, it is malleable ; and, 
when annealed, may be passed through rollers, and 
formed into thin sheets or leaves. Although, pre- 
viously to being thus heated, it is brittle ; on now 
cooling, it continues soft, flexible, and ductile. The 
inconvenience arising from the brittleness of the zinc 
being removed, this metal is applicable to many useful 
purposes. It may even be drawn into wire, but the 
tenacity of this is not great : a piece of zinc wire, one 
tenth of an inch in diameter, will sustain only a weight 
of twenty-six pounds without breaking. It has been 
proposed to substitute zinc in the place of tin for the 
lining of copper vessels ; but it has not hitherto been 
ascertained whether this can be done with effect, and 
without injury. Prizes have of late been offered, to a 
considerable extent, in France, for the ascertainment 
of this fact. In China, zinc is employed as a current 
coin of the country ; and for this purpose it is used in 
the utmost purity. The Chinese also, as well as the 
artists of our own country, employ it to a great extent 
in various alloys. It is used in the manufacture of 
brass, pinchbeck or prince's metal, and bronze, all of 
which consist of this metal in combination with different 
proportions of copper (230). Tutenag is a well known 
white metal, made principally of zinc, and used for 
forming candlesticks and other articles. When tutenag 
is well manufactured, it is of good colour, and not more 
disposed to tarnish than silver. Zinc is one of the me- 
tals employed to form the galvanic or voltaic appara- 
tus ; and its filings are mixed with gunpowder, to pro- 
duce those brilliant stars and spangles which are seen 
in the best kinds of artificial fire-works. Preparations 
of zinc are occasionally used in medicine. If a thin 
