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POPULAR SCIENCE REVIEW. 
15 of carbonate of soda, 10 of nitrate of potassa, and 5 parts of magnesia 
alba. The molten mass is poured into water, and afterwards mixed with 
6|- parts of powdered quartz, 3§ of oxide of tin, § of carbonate of soda, 
and f parts of magnesia alba, and the whole of the ingredients very finely 
ground along with water, so as to constitute an inpalpable powder. The 
metal to be enamelled is first cleaned with dilute sulphuric acid (1 part of 
strong acid to 24 of water), then rubbed with sharp sand, rinsed in hot 
water, and immediately afterwards dried ; the enamel masses are next burnt 
on. Well-made enamel exhibits the following characteristics: — A perfectly 
smooth and level surface, so that the surface nowhere feels uneven or rough 
to the touch ; a pure white colour j absence of small cracks. 
Copper and Manganese Alloys. — Mr. J. F. Allen, F.C.S., has made several 
interesting alloys of the above. These are, shortly, 1st, Manganese and 
copper in various proportions, from 35 per cent, to 5 per cent, of iron, as 
ingot, sheet, or wire ; 2nd, Copper, zinc, and manganese, also in different 
proportions, and in a variety of applications ; 3rd, Copper, zinc, man- 
ganese, and tin as ingots and as bearing ; 4th, Copper, manganese, and tin 
in several different proportions as bars ; 5tli, Copper, manganese, and 
lead. 
The Metals in the Sun. Reversal of Sodium Lines. — Mr. C. A. Young writes 
a letter to Professor IT. Morton (published in the u Chemical News,” Oct. 21) 
regarding some recent spectroscopic observations in the sun. The following 
is the letter : — “ Dartmouth College, Hanover, N. H. ; Sept. 26, 1870. — My 
dear sir, — I write to inform you that last Saturday, Sept. 22, about 11 A.ir. 
Hanover mean time, I was so fortunate as to see the sodium lines D, and D 2 
reversed in the spectrum of the umbra of a large spot near the eastern limb 
of the sun. At the same time C and F lines were also reversed, but w r ith 
the great dispersive power of my new spectroscope I see this so often in the 
solar spots that it has ceased to be remarkable. In the umbra of the spot 
the D 3 line was not visible, but in the penumbra was plainly seen, as a dark 
shade. I am not aware that this reversal of the sodium lines in a spot- 
spectrum has ever been observed before ; its reversal in the spectra of pro- 
minences is not very unusual. A small prominence on the western limb of 
the sun, which was visible the same forenoon, presented all the following 
bright lines, viz. C, Dj, D 2 , D 3 , 1474*, b v b 2J & 4 , 1989-5, 2001*5, 2031*, F, 
2581*5, 2796*, and h ; fifteen in all. In the spot-spectrum the magnesium 
lines b v b 2 , and b v were not reversed, but while the shade which accom- 
panies the lines was perceptibly widened, the central black line itself was 
thinned aud lightened.” 
What is Wocheinite?- — Dr. H. Schwarz (in u Dingler’s Journal”) gives 
an account of some experiments made with a hydrate of alumina found in 
the Wochein, and akin to the Bauxite. This wocheinite consists, in 100 
parts, of— alumina, 56-82; silica, 11*28; peroxide of iron, 1*60; water, 
24*20 ; traces of carbonate of lime and of manganese. The mineral is suit- 
able for being mixed with other fire-clays (it is not sufficiently plastic by 
itself, even when pulverised), and for the manufacture of aluminate of 
soda and other salts of alumina. 
Composition of Columbite , Ferro-ilmenite, and Samar shite. — In the 
“Journal fiir prakt. Chemie,” No. 13, Herr A. Hermann states the 
