GASEOUS SPECTRA IN VACUUM TUBES. 103 
made before by some one else, opens up now some most noteworthy views in 
the quasi-vital chronology of the stars of heaven itself. 
Thus our Sun has been roasting for long geological, as well as human- 
historic periods in a temperature still higher than ordinary electric sparks ; 
and what do we find there touching these two critical gases, Nitrogen and 
Hydrogen? That there is no Nitrogen, but overwhelming Hydrogen, in the 
Sun: or we might say, that its once supply of Nitrogen has been long since 
converted by continued supernal electric heating into Hydrogen. 
But in that case the beginning of the Sun’s luminous history was probably 
marked by Nitrogen preponderating over Hydrogen ; and what do we find on 
recurring to Dr Huaerns’ remarkable observation on those agglomerating 
materials for Suns about to be, viz., the nebulee ? 
The answer is, “one faint hydrogen, but a much stronger and double 
nitrogen, line.” 
On RECENT OBSERVATIONS IN BELGIUM. 
(Paragraph added during printing.) 
If the question be next put, ‘why only one line of each of those gases was seen, when their 
usually admitted spectra contain several, or many,”—the answer was not only given by Dr Hueains 
himself, to the effect that the visible line in the Nebula, was in each case the brightest of the several 
lines in the terrestrial spectrum of either gas ;—but special observations for the verification of, and with 
the effect most certainly of verifying, that great master-spectroscopist’s view, have lately been made at 
the newly re-organized Royal Observatory of Brussels. 
M. Fievez, the spectroscopic astronome-adjoint there, had already communicated several researches 
on allied points in spectroscopy to the Académie Royale de Belgique, when he took up this question, 
with results now published in the Academy’s Bulletins, 2™° serie, tom. Ixix. N° 2, 1880; and his 
apparatus was so vastly superior to mine, as to supply some much desired data for its possible future 
extension and improvement. Thus, while M. Finvez employed end-on tubes very like my own, he 
‘illuminated them, not by such wretched little sparks as I was confined to by private economy, viz. 
sparks generally under 1 inch, or even half an inch long,—but by sparks 20 inches long, procured from 
a very large induction coil, excited by a Bichromate battery of 8 couples (size not mentioned); and 
these sparks occasionally intensified by the use of a condenser of 6 square yards of surface, employed 
sometimes in tension and sometimes in quantity. 
Now as my condenser consisted only of one quart-sized bottle, and I was even afraid of using that 
much lest the glass tubes should crack,—I wrote to M. Firvez asking how he contrived to ensure the 
safety of his tubes, when tried in such almost fearful light and heat. 
He kindly replied “that he always began by very slowly immersing the zincs of the battery into 
the acid solution, producing only a feeble current.” Some instants afterwards he introduced the con- 
denser im tension into the circuit, and then immersed the zincs a little more. Lastly he disposed the 
condenser in quantity (as a single element); but he was careful to keep it acting in that manner only 
for a few minutes because the heating of the capillary if the so illuminated vacuum tube became too 
considerable. He further added, that a tube of Hydrogen-vacuum which had served for many experi- 
ments of that kind, presents now a deposit of metallic aluminium (derived from the electrode wires) at 
one of its extremities, 
Of course the brightness of the spectra presented by M. Frevsz’ tubes under 20 inch sparks or their 
condensed equivalents, was magnificent, delightful to the observer to behold, and greatly promotive of 
exactness in any mensurational applications. Of course also his Nitrogen tubes showed the sharp linear, 
not the faint band, spectrum of that gas; and equally of course the 4 classical, high-temperature lines of 
