REPORT ON GILDING, ETC. 
65 
copper, bronze, brass, iron, and cast iron itself, by operating 
without heat, on all kinds of utensils. 
Cobalting, Nickeling, fyc. — M. Dumas exhibited to the 
Academy several pieces of metal covered with nickel or co- 
balt. Nickel is very readily applied to iron, which may 
become of great importance* 
Zincing. — Among the experiments tried by Mi De Ruolz 
those which refer to the zincing of metals, and of iron in 
particular, were very interesting to the committee. 
Zinc, when applied to iron, doubly preserves it; it pro- 
tects it like a varnish, and likewise by a galvanic action. 
This peculiarity accounts for the success which zinced iron 
has obtained in all the applications in which iron, or iron 
plate employed cold, did not require all their tenacity, and 
could support additional expense. 
The zincing of iron, made by steeping iron in a bath of 
melted zinc, has some inconveniences ; besides, the iron 
combining with the zinc, constitutes a very brittle super- 
ficial alloy; the iron loses its tenacity, a circumstance which 
is not perceived, however, except in trying to zinc fine iron 
wire or very thin plates. Besides, the surface, thus covered 
with a layer of a not very fusible metal, is always ill- 
formed. 
Thus, by this process fine iron wire cannot be zinced ; 
it would become fragile and deformed : bullets cannot be 
zinced, as they become misshapen and no longer of the 
same calibre. 
Manufacturers, and those concerned in military affairs 
and the fine arts, will learn with interest that the processes 
of M. De Ruolz enable us to zinc, in an economical manner, 
iron, steel, and cast iron, by means of the pile, with the so- 
lution of zinc ; by operating without heat, and consequently 
not interfering with the tenacity of the metal ; by applying 
it in thin layers, and by thus preserving the general forms of 
the pieces, and even the appearance of their minutest de- 
tails. 
6* 
