1868. | Physics. 423 
After the charge of iron has been blown, it is run into the ladle, 
and a certain quantity of the highly carbonized spregelezsen is run 
into it. The effect of the addition of the spiegeleisen is the produc- 
tion of a flame which is larger and stronger when the blow has been 
carried rather far. This flame occasionally gives the same spectrum 
as the ordinary Bessemer-flame; but more commonly a quite dif- 
ferent spectrum is seen, which reminds one at first of the ordinary 
carbon-spectrum, but differs from it very remarkably. 
In the carbon-spectrum each group of lines has its strongest 
member on the left (¢.e. less refrangible), and fades gradually away 
towards the right hand: in the spectrum of the spiegel-flame the 
reverse is the case ; each group has its brightest line most refrangible, 
and fades away into darkness on the least refracted side. A compa- 
rison of the drawing of the spectrum of the spiegel-flame with that 
of the Bessemer-flame will show that they really contain the same 
lines; but the general appearance of the spectrum is completely 
changed by alteration of the relative brightness of the lines. This 
was shown by direct comparison of the actual spectra. 
Dr. Watts concludes his paper by saying:—There can be no 
- doubt that the principal lines of the Bessemer-spectrum are due to 
carbon in some form or other. My own belief is that they are due 
to incandescent carbon-vapour. The experiments in which I am at 
present engaged have already shown the existence of two totally dif- 
ferent spectra, each capable of considerable modification (consisting in 
the addition of new lines) corresponding to alterations in the tem- 
perature or mode of producing the spectrum, and each due to incan- 
descent carbon. It is possible that the Bessemer-spectrum may 
prove to be a third spectrum of carbon, produced under different 
circumstances from those under which the ordinary carbon-spectrum 
is obtained; and the intensity of the dark bands is more probably 
due to contrast with the extreme brilliancy of the bright lines, than 
to their actual formation by absorption. 
At one of the recent meetings of the Manchester Literary and 
Philosophical Society, Mr. Dancer made some remarks on crystals 
containing fluid. The author has examined a large number of 
crystals of various kinds, from the collections of friends; and has 
found fluid in quartz from South America, Norway, the Alps, 
Ireland, Snowdon, and the Isle of Man; and in fluor-spar from 
Derbyshire ; this latter specimen contained a considerable quantity 
of fluid, which burst the crystal at 180° F. He suggests the 
employment of the microscope as a valuable assistance in detect- 
ing spurious from real gems; very few of the latter are perfect, 
and the flaws and cavities are so distinct in character from those 
which are so abundant generally in artificial gems that very little 
experience is sufficient for the purpose. This mode of testing, of 
VOL. V. 2G 
