48 
SCIENCE. 
THE “ D-LINES ” SPECTRA.— ARE THEY DUE 
TO WATER? 
By Lieut-Colonel W. A. Ross, late R. A. 
In the year 1834, Mr. Fox Talbot, F. R. S., attributed the 
all but omnipresent rays affording the above-named spectra 
to water, on account of its universality ; but the celebrated 
experiment of Kirchoff has, since then, reversed that opin- 
ion, and bestowed the power of emitting orange rays upon 
sodium alone. 
Is it not more reasonable, however, to suppose that sod- 
ium has more attraction for water than any other substance, 
than to imagine sodium contained in every possible sub 
stance, from the eternally-burning Sun himself, down to 
every particle of our atmosphere? 
A man need not be a chemist, or pyrologist, to observe 
that, if he holds in platinum tongs a fragment of marble, 
or artificial carbonate of lime, or magnesia, before the blow- 
pipe, a strong orange flame affording “ D-lines” spectra is 
emitted by the fragment, only so long as it is imperfectly cal- 
cined , or, in other words, has lost its carbonic acid gas. 
When calcination is complete, it begins to glow brightly, 
and emits no colored “ flame ” at all. Let us call this orange 
flame (a) in this case. According to modern chemical theo- 
ries {a) can only be one of two things ; carbonic acid gas or 
sodium. It cannot be carbonic acid, which so far from being 
combustible, is used to “ put out” flame. It can be proved 
not to be sodium by making it impinge upon a bead of pure 
transparent boric acid, in which it causes, after a time, 
opalescence. This opalescence is removed by the similar im- 
pingement upon the bead of an indubitable sodium orange 
flame. Reasonable chemists, therefore, will not be inclined 
to contradict Euclid that the same cause producing precisely 
opposite effects is a reductio ad absurdum. Moreover, for 
the supposed sodium to have been with the marble, and not 
with the marble after calcination — “ hie et ubique like the 
ghost of Hamlet’s papa — is another absurdity, which no 
modern chemist would require us to believe, although some 
are very exacting if not always exact. May I hope that 
most chemists will be now inclined to admit, first, that ( a ) 
can be due neither to sodium nor to carbonic acid ; and 
sacondly, that it must, therefore, be due to something else : 
and this is the very impression that occurred to me after 
thinking profoundly over the matter for several years. 
Indeed, I suggested to Mr. Hennessy, who was engaged 
in making atmospheric observations at Mussooree, in 
India, with a spectroscope belonging to the Royal Society — 
and who was elected an F.R.S. for his pains — that the 
“ D-lines ” were due to water, not sodium, so long ago as 
1871, and he was very much struck by the suggestion. 
The methods I adopted to prove the truth (or improb- 
ability) of the suspicion which thus arose in my mind were 
as follows : 
1. — The whole of (a) in a weighed fragment of pure 
marble was obtained by fusing it carefully before the blow- 
pipe in a transparent bead of boric acid, when the carbonic 
acid gas, which we may call ( b ), escaped in bubbles with 
great effervescence, (a) remaining behind as opalescence, 
and the lime (c) combining with a portion of the boric acid 
to form a ball contained in the bead— let us call the bead 
( d ). I found the weight of the lime borate ball (r a) bore 
the same relative proportion to that of the marble (a b c) 
whether the latter had been previously calcined or not, so 
that the opalescence in (d) could not possibly have been 
part of ( c ) while (b) escaped in bubbles ; therefore the 
opalescence must have been due to (a) or — 
i (ball) ) 
{a be) + 2 (d)-{b) = | M 1 
( (hydrated boric acid) ) 
i {ad) S 
I could not isolate (a) any further than this, because (a d) 
or what I believed to be hydrated boric acid is, naturally, as 
soluble in water as ordinary boric acid, so I tried — 
2. — Observing that platinum in considerable bulk also 
produces (a) in a ratio increasing with the decrease of 
temperature down to a dull red heat, I fused an ounce oi 
crystallised boric acid in an open platinum dish at red 
heat, and obtained a new kind of boric acid, which turns 
brown with a strong resinous smell , on being ignited, like 
that of burning sealing-wax, affords a slightly-oranged 
“ flame ” — for the green pyrochrome of the boric acid over- 
powers that of (a). — and forms an opalescent bead, which 
reacts, as I believe, with much greater acidity before the 
blowpipe than ordinary boric acid does. 
This I call platinised or hydrated boric acid , and shall be 
happy to show it to any chemist who may consider the 
matter to be sufficiently interesting. — English Mechanic. 
AN IMPORTANT DISCOVERY. 
A discovery in chemistry has just been published, which 
bids fair to influence agriculture in a manner that may be 
well described as revolutionary. It must soon compel the 
attention of farmers and manufacturers of artificial manures 
everywhere. The essential part which ammonia plays in 
vegetation need not here be dweit upon, and no one will 
question the desirability of securing it cheaply and in quan- 
tity. The importance of the recent feat of Messrs. Rick- 
man & Thompson, of England, disclosing a plan by which 
ammonium sulphate can be made and sold with profit at 
two cents a pound, will not, therefore, be liable to be over- 
estimated. The following account of the process is taken 
from the Chemical Neivs : 
Within the last twenty years the manufacture of ammonia 
synthetically has been several times attempted, and though 
in every attempt it is probable that ammonia has been made, 
it has never been produced on a commercial scale. In all 
these attempts ihe process has been to combine the nitrogen 
and hydrogen directly at a low temperature, and receive the 
ammonia in solution in water, or by substitution, first form- 
ing a cyanide at a higher heat, and then indirectly produc- 
ing ammonia by the decomposition of the cyanide, the result 
in both cases being ammonia in solution with water. Rick- 
man & Thompson’s procedure is altogether different, they 
produce ammonium chloride direct, either in dry powder or 
in solution, and this by the simplest and most inexpensive 
means. Instead of employing retorts, as in all other places, 
they merely use a closed brick furnace, the ash-pan of which 
regulates the supply of air, and they cause the vapor of 
water to be produced by the waste heat of the furnace itself. 
With the exception of about a bushel of coke for starting 
the furnace, the deoxidizing material and only fuel used is 
coal-dust. The great difficulty in making ammonia from the 
nascent hydrogen of water and the nitrogen of the air is the 
restricted limits of temperature between generation and 
decomposition, it being necessary that carbon, however used, 
should be at a full red heat to decompose the vapor of water, 
and at a bright-red heat to decompose ammonia. Now, 
ammonium chit ride under the same conditions is simply 
volatilized and not decomposed. As chloride of sodium or 
of calcium is decomp sed at a full red heat in presence of 
nascent ammonia, therefore one of these chlorides is mixed 
with the eoal that ammonium chloride may be formed ; so 
that if by chance the heat should be raised to a bright red, 
no loss will be sustained— the ammonium chloride is simply 
volatilized. By these means a greater range of working 
temperature is obtained. At the present time, with the 
consumption of from 20 to 28 lbs. of coal-dust and salt 
mixed, from two or three lbs. of ammonium chloride is 
formed. 
A New Audiphone. — Further experiments on the tim- 
bre of musical instruments as rendered by the audiphone 
have led me to the selection of the following as a distinct 
improvement on the birchwood veneer, both for musical 
purposes and also for ordinary conversation. It has the 
same advantage as my previous form in not requiring to 
be held by the hand, it costs nothing, and requires no 
making. Take a sheet of stiff brown paper about 11 x 15 
inches, the paper being such as is ordinarily used for mak- 
ing up heavy parcels. Put the ends together, the middle 
forming a loop, and hold the ends between the teeth. The 
paper must be pretty stiff, as the loop must stand out 
round and full, and of course the paper must be without 
folds or creases. Thomas Fletcher. 
