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MIXING METALS.--All the hard gray American charcoal iron, of which
car wheels and all such work are made, requires more heat and a longer
time to melt than soft iron, especially Scotch pig, which is the most
fluid and the easiest to melt of any iron. Consequently, unless the
melter exercises good judgment in charging, the Scotch pig will
melt and run off before the car-wheel iron is melted. If G. H. P.
be particular in the quality and strength of his iron, he will make
better results by using soft American charcoal pig, with old car-wheel
iron. It will make stronger castings, mix better, and melt more
uniformly; but he should always recollect in charging his furnace that
soft iron will melt before hard in the same position, in the cupola. I
also think he had better use a larger proportion of soft pig, as every
time cast iron is melted it becomes harder, so much so that iron which
can be filed and turned with ease, when re-cast will often be found
too hard to work.--J. T., of N. Y.

HARDENING TALLOW.--If E. H. H. will use one pound of alum for every
five pounds of tallow, his candles will be as hard and white as wax.
The alum must be dissolved in water, then put in the tallow, and
stirred until they are both melted together, and run in molds.--F. O.
H.

L. L., of N. Y.--According to Ure, strass is made as follows: 8 ounces
of pure rock crystal or flint, in powder, mixed with 4 ounces of
salt of tartar, are to be baked and left to cool. The mixture is then
poured into hot water, and treated with dilute nitric acid till it
ceases to effervesce, and the "frit" is then washed in water till the
water comes off tasteless. The frit is then dried, and mixed with 12
ounces of white lead, and this last mixture reduced to fine powde