338. 
logues of this hydro-carbon, and gave, even with toluol, 
but small quantities of the alcohol. 
Herr Beilstein, however, took up the matter at the 
point where others had abandoned it. He showed that 
when chlorine is made to act upon heated aromatic hydro- 
carbons, there is obtained a chloro-derivative, easily acted 
upon by acetate of silver or of potassium, and consequently 
admirably fitted to furnish the corresponding alcohol ; 
whilst on the other hand when used cold, a very stable 
chloro-substitution compound is formed of the same com- 
position, but furnishing no alcohol. 
From this moment no difficulty remained in complet- 
ing the series of the aromatic monatomic alcohols ; but 
up to this time no diatomic alcohol, or aromatic glycol 
was known. It was, however, evident that the prepara- 
tion of such compounds was possible, inasmuch as the 
knowledge already existed of such acids as formobenzoilic 
acid, and terephtalic acid, which bore the same relation 
to these unknown bodies as glycolic and oxalic acids to 
ordinary glycol. 
M. Edouard Grimaux, after much long and careful in- 
vestigation, has at length filled up the blank by the dis- 
covery of tolylenic or xylenic glycol, that is to say a 
glycol which presents in its composition xylol to which 
two atoms of oxygen are added without substitution. 
To obtain tolyl-glycol M. Grimaux takes the xylol of 
commerce which he raises to the boiling point in a retort, 
surmounted by an inverted refrigerator, from which the 
condensed vapours flow back into the retort, the tubulure 
of which is closed by a cork, into which a funnel with 
a tap isinserted. He then introduces drop by drop into 
the boiling hydro-carbon half its weight of bromine. The 
bromine is at once absorbed with the production of hydro- 
bromic acid, and on cooling a black crystalline mass is 
obtained which is first washed with ether, and its purifica- 
tion completed by crystallisation from chloroform. This 
substance is a bibromo-xylol easily acted on by re-agents. 
Treated at a temperature of 150°, or ina closed vessel 
with an alcoholic solution of acetate of sodium, the bromo- 
product gives rise by double decomposition to bromide of 
sodium and to diacetate of tolylene, which takes the form 
of beautiful colourless crystals. 
Subjected in its turn to the action of thirty times its 
weight of water at a temperature of 170° or 180° in a closed 
vessel, this acetate of tolylene is separated into acetic 
acid and tolylenic glycol, which, on the opening of the 
tube and by the evaporation of the liquid, is deposited 
in needle-shaped crystals. 
The formation of tolyl-glycol may be represented by the 
following equations :— 
. CH; (Pr ey 3: he aes CH.DBr 
»  Gst< GH? + Ag B= o(H\) + catty< ier 
Xylol. Tromine. Ilydrobromic Bromine of 
acid. tolylene. 
2, CoHy <i Br 4 oC, Hy Oz Na)= 2 Na Br + CoH, < SE Hes 
LPromine of Acetate of Bromide of Acetate of 
tolylene. sodium. sodium, tolylene. 
z GH. GCH.Q.. . «iH OR ics a CH, OH 
a Cas Gile GipG2 + 2 (i) O) = 2(CHs0.H) + Coi< Cy? OH 
Acetate of Water. Acetic acid. Tolyl glycol. 
toluol, 
The path is now open, and nothing will be easier than, 
by following the method proposed by M. Grimaux, to pre- 
pare all the aromatic glycols, of which the hydrocarburets 
ure already known to us. ALFRED NAQUET 
SPECTRUM OF A SOLAR SPOT, APRIL 9, 1870, P.M. 
Pe XAMINED the spectrum of a large group of spots 
a little north and east of the sun’s centre, 
The nucleus of the most southerly member of the group 
* Communicated by the Author. 
NATURE 
[ Aug. 25, 1870 
reversed the C line finely, turning it into a conspicuous 
bright line for about 20” of its length, without any dis- 
tortion, however, such as is common upon this (dark) 
line in the neighbourhood of spots. 
F was also reversed, but rather faintly. 
D, could not be made out at all in the nucleus spectrum ; 
neither were 2796 (the numbers refer to Kirchhofi’s map) 
nor / reversed, I thought, however, that they were 
somewhat ¢hizned. 
The reversal of C and F continued through the whole 
afternoon. 
On the other hand, many of the dark lines were 
widened and deepened in this nucleus spectrum in the 
manner which the description and figures of Mr. Lockyer 
have made familiar. Many also were unaffected. Ae 
these were notably @, B, E, 1474, the four lines of 4 ian 
and G, er, 
The two sodium lines D, and D., and 8; 5 
distinctly, but not greatly, widened. » and 830 (Fe) wore 
The effect was most marked upon the following : 
(Ca), 877 (Fe?), 885 (Ca), 895 (Ca and Li), rae fon 
1599 (Ti), 1627 (Ca), and 1629 (Ti). Ihave marked 877 
doubtful, because there lies very near it a line whose 
origin is unknown, and I am not sure to which of the two 
the thickening was due. The Titanium lines are identi- 
fied as such by reference to Angstrém’s Atlas, I was 
greatly surprised at the prominence they assume in the 
spot-spectrum, as they are inconspicuous in the normal 
5 dai anda similar remark applies to the calcium 
ines. 
ido not intend to convey the idea that the lines 
mentioned were the only ones that were much deep- 
ened ; there were many others, mostly faint, affected to 
nay the same degree, but I had not time to identify 
them. 
There was at the same time an exceedingly brilliant 
protuberance on the south-west limb of the sun (position 
angle 230°), near but not over, a large spot which was 
just passing off. At the base of this prominence, which 
was shaped like a double ostrich plume, the € line was 
intensely brilliant, so that the slit could ‘be opened to its 
whole width in studying the form above described, but it 
was not, so far as I could see, in the least distorted. On 
the other hand, the I line, also very brilliant, was shattered 
all to pieces, so that at its base it was three or four times 
as wide as ordinary, and several portions of it were en- 
tirely detached from the rest. The figure, without pretend- 
ing to exact accuracy, and for the sake of distinctness a 
little exaggerated, gives a fair idea of the nature and 
extent of the “ shattering” alluded to. 
Since the C line was not similarly affected it is hardl 
possible to attribute this breaking up of F to cyclone 
motions in the gas from which the light emanates, and it 
becomes very difficult to imagine a cause that can thus 
disturb a single line of the spectrum by itself. Possibly 
this appearance may be the result of local absorptions 
acting upon a line greatly widened by increase of pressure 
or temperature. 
It continued unchanged for more than half an hour, 
and until the sun passed out of sight behind a building. 
The observations were made with the 5 prism spectro- 
scope. { C. A. Youne. 
Hanover, New Hampshire, May 20 aj 
