Fuly 30, 1885] 
NATURE 307 
~) 
Pararosaniline FERENCE. 7 Gere! 
H i Sear 
ydrochloride ( NH,C,H,/ 
Aniline blue NHPhC gH, / Cs>H,NPhHCl 
C | 
Triphenylpararos- 
aniline. | NHPRC,H,/ me 
N,SOz | Na 
NupPh j CHa \ Cos (Neh * 
Soluble blue de | 
NaSO, 
Napr | Coy / 
Methyl violet ) N(CHg),CoHg._//CyH,N(CH,),Cl 
Hexamethylpara- C_ | 
msailing al N(CH,).C,H,” 
Methyl green N(CH5)2CoHa / CaH4N(CHsy),Cl 
Heptamethyl- DE 
rosaniline } N(CH,),C,H, 
Cl 
Victoria, 
or Benzaldeyhde 
green. 
N(CHy),CsH,. /CsHsN(CH,).Cl 
*"Nc | 
Cpe 
\_/CHAN(CoH)2C1 
Cc l 
{ N(CoH)sCoH 
Gril eae 
The effect of replacing hydrogen by hydrocarbon radicals in 
rosaniline is seen to result in the shade of colour becoming blue 
for each hydrogen replaced—the effects of those of high molecular 
weight, such as phenyl, being to produce the bluest shades ; thus 
triphenylrosaniline is blue, whilst hexamethylrosaniline is blue- 
violet, notwithstanding it contains six hydrogens replaced. 
After all the replacements possible have been effected, as in 
hexamethylrosaniline, the result of the combination of the pro- 
ducts with halogen compounds of methyl is very interesting. 
The particular group to which this is attached becomes of the 
nature of an ammonium, and the colour changes to green—z.e., 
methyl green—and this, like other ammonium compounds, when 
heated, dissociates, with loss of the halogen compound of 
methyl, and then hexamethylrosaniline is reproduced. Again, 
ifthis ammonium group be replaced by phenyl, we also get a 
green—z.e., Victoria green. 
The structure of some of these bodies has been proved by 
another most beautiful synthetical process, which has lately come 
into use—a process which enables us now not only to say that 
we employ the volatile products of the distillation of coal, but 
also the coke itself; as carbonic oxide, in combination with 
chlorine, is one of the important agents—z.e., phosgene or car- 
bonoxychloride is used. This product was discovered in 1812 by 
J. Davey. 
In 1876 W. Micbler gave an account of his researches on the 
synthesis of aromatic ketones by means of phosgene (Ber. ix. 
716), in which he showed by the action of this substance on 
dimethylaniline that a tetramethylised diamidobenzophenone 
was contained. This substance has, therefore, the constitu- 
tion— 
Brilliant green 
N(CH,),C,H, - CO - C,H,(CH,).N. 
The formation of this product takes place in two phases, but I 
need not enter into that now. 
The first experiments to turn Michler’s synthetically prepared 
tetramethylated diamidobenzophene to practical account were 
made by Dr. A. Kern, in the works of Bindschedler, at Basle. 
Dr. Kern proved that an agent like phosgene might be produced 
on a larger scale, and he invented a process to convert Michler’s 
ketone base into methyl purple. This process was derived from 
the ketone synthesis of triphenylmethane from benzhydrol and 
benzene, and consisted in preparing the tetramethyldiamido- 
benzhydrol, and condensing the latter with dimethylaniline ; 
thus the leuco base of hexamethylrosaniline was obtained, and 
then oxidised with lead peroxide. This process, which was too 
costly for practical’ purposes, has been superseded by one dis- 
covered by Dr. Caro, who has found that this ketone base can 
be made to form condensation products with dimethylaniline and 
other products directly, by the use of phosphorus trichloride— 
this substance converting it first into a chloride, which then 
~ reacts on the dimethylaniline, thus— 
N(CH,),C,H,-CC€l, - C,H,(CH,),N + N(CH,),C,Hs= 
N(CH),CoHy_//CoH,(CH,)2N, Cl 
Cc 
: [> FHC! 
N(CH,).C,H,% — 
And this reaction takes place quantitatively, the body being so 
pure that it readily crystallises from water in prisms, like potas- 
sium permanganate, only with very much more brilliant lustre. 
These contain water of crystallisation. The condensation can 
also be effected with phosgene gas. The colouring matter ob- 
tained by this means is bluer than that obtained from dimethyl- 
aniline by oxidation, which consists chiefly of the pentamethyl 
compound,! 
Diethylene can also be made into a ketone with phosgene or 
carbon oxychloride, and this product condensed with diethyl- 
aniline yields hexaethylpararosaniline. 
Instead of dimethylaniline, dimethyl-a-naphthylamine can be 
used, and in this case a beautiful blue colouring matter is ob- 
tained, and if a-phenylnaphthylamine, the Victoria blue is pro- 
duced, and by varying the reaction in this kind of way a great 
variety of colouring matter can be synthetically prepared. 
With ammonias this ketone condenses to form the new yellow 
colouring matter, auramine, with aniline phenylauramine. With 
quinoline it produces a green very similar to Victoria or benz- 
aldehyde green. I must not, however, spend any more time over 
this interesting part of the subject, but may say here again we 
have pure scientific research, conducted for its own sake, bearing 
fruit. The discovery of W. Michler, which remained for seven 
years a matter of theoretical interest, now comes forward as a 
matter of practical value. 
(To be continued.) 
THE DEVONIAN SYSTEM OF RUSSIA 
M P. VENUKOFF has recently given a general sketch of 
* the Devonian rocks of Russia. As is well known, these 
rocks, so largely developed in Russia, contain such a peculiar 
fauna that geologists have been puzzled to establish a parallel 
between them and the different subdivisions of the Devonian 
system of Western Europe. Two great areas of Devonian 
strata are known in Russia: that of the north-west and that of 
the central basin. From Esthonia and Livonia the former ex- 
tends north-eastwards to Lake Onega and perhaps even to the 
White Sea, and southwards through Pskor and Vitebsk to 
Moghiber. In Smolensk only traces of Devonian rocks have 
been found ; but further south-east a great tract of these rocks 
runs through Tula, Orel, Voronesh, Ryazan, and Tamboff. 
Prof. Grewinck, in his ‘‘ Geologie von Livonia und Kurland”’ 
in 1861, and again in 1879, and Prof. Barbot de Marny, in the 
Russian AZning Fournal of 1878, attempted to classify the 
Russian Devonian deposits ; not to mention the earlier English 
work of Murchison, followed by those of Pander, Pacht, Hel- 
mersen, and Kutorga, and recently by those of MM. Stucken- 
berg, Inostrantseff, and Romanoysky. The mixed characters 
of the fauna have thus always presented great difficulties in the 
way of satisfactory correlation. 
The recent monograph by M. Tschernyskev (Mem. Geol. 
Committee, i., 3) shows how rich a field remains to be explored 
before our knowledge of the Devonian fauna of Russia in any 
measure approaches completion. 
M. Venukoff, in his 7é¢semé of the present condition of the 
problem, gives a brief account of all that is known as to the 
Russian Devonian system in each separate government, followed 
with an analysis of the work done by previous geologists. He 
then presents a detailed exposition of his own observations and 
conclusions in North-West and Central Russia; giving long 
lists of fossils which comprise the rich collections recently made 
by M. Antonowitsch. Inthe north-western basin three strati- 
graphical series have long been known: the lower sandstones, 
the middle limestones and dolomites, and the upper sandstones. 
The lower member contains only fishes and small Zzz2ule, 
though on the Oyat the ichthyolites are accompanied with 
Rhynchonella livonica, Streptorhynchus crenistria, Avicula ros- 
trata, [socardia, and numerous Alge. The fauna of the lime- 
stones is mostly that of deeper water, but even among these 
strata there occur occasionally—as at Lake Ilmen—beds of 
sandstone with shallow-water forms (the fishes Coccosteus, 
Asterolepis, Osteolepis, and the little Lingula bicarinata, Kut.). 
On the whole the middle limestones of Pskoy and Novgorod may 
be sub-divided into four stages or zones characterised, the first, 
by Rhynchonella Meyendorfii, Rh. livonica, Spirifera muralis, 
Atrypa reticularis, Orthis striatula, and Strophalosia product- 
1 See Patents, Caro, 4428, September, 1893; 4850, March 13, 18843 and 
5038, March 18, 1884. 
