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Miscellanies. 395 
article on cupellation, where the writer proposes to separate silver or 
gold from lead by oxidizing the alloy in the external flame of the blow- 
pipe on a slip of mica. This process is undoubtedly original with him, 
but a much better one has been practiced by me more than thirteen 
years, when | first learned it from Prof. H. Rose of Berlin. 
Take a few grains of bone ash, make it into a paste with a little 
saliva, spread it about one line thick on a piece of charcoal, and make 
a shallow impression in it, to receive the globule of metal. Expose it 
to the heat of the blowpipe, so as to burn it white and hard, and then 
melt the globule of the alloy on it, and keep it in a constant red heat, 
till the lead is all oxidized. 
The advantages of the bone ash over the mica are manifold. 1. It 
is easier to be obtained, and every where the operator can prepare a 
little if he should not be supplied with it. 2. The metal will remain 
in the concavity of the bone ash paste, and not be liable to run down 
and be lost, as on the mica. 3. It. is never necessary to change the 
material ; the bone ash absorbs the litharge*which collects on the mica, 
and impedes the process, so that the remaining metallic globule has to 
be transferred to a fresh slip of mica. 4. The color of the paste, after 
the operation is finished, gives an indication as to the nature of some 
impurities of the metal; lead alone makes it appear yellow; a small 
Proportion of copper changes this yellow color to greenish. Respect- 
fully, your obedient servant, Georce Encetmann, M. D. 
St. Louis, Jan. 22, 1842, : 
12. Suggested observations relating to the total solar eclipse of July, 
1842, visible in Eurape.—The sun is supposed to belong to the class of 
nebulous stars. The nebula that surrounds him is however, at ordinary 
times, very incompletely visible, being hidden by the effulgence which 
his reflected beams pour upon the eye from the atmosphere, and from 
the whole assemblage of terrestrial objects in the field of vision. It is 
only when this effulgence is withdrawn, and evening is far advanced, or 
the morning yet distant or scarcely beginning to glimmer, that this 
nebula may be observed in its remoter parts, lifting itself above the 
twilight, and forming the celestial phenomenon known commonly as 
the “ Zodiacal Light.” Atsuch times, however, the central body and 
the brighter regions of the nebula are concealed beneath the horizon. 
Our only opportunity, therefore, for a complete observation of the 
zodiacal light, in its brightness near the sun, in the gradations of bright- 
Ness as it recedes from that orb, and in the relative visual extensions 
estimated along the zodiac and across it, would seem to be on those rare 
Occasions when one may stand, during a total solar eclipse, quite within 
the path of total obscuration. I suppose, however, that no such occa- 
