408 
NATURE 
[ Sept. 15, 1870 
shown lie between mellitic and benzoic acid, and in which from 
1 to 6 atoms of hydrogen in benzol are respectively replaced by 
carboxyl. Nor is this all, for he has proved that, with two ex- 
ceptions, each of these six acids is capable of existing in three 
isomeric modifications, thus giving us an insight into the arrange- 
ment of the molecule of these aromatic compounds. — For the 
simplest mode of explaining these numerous isomers is that given 
by Baeyer in the different order in which the several atoms of 
hydrogen in the benzol molecule are replaced, _ Thus in the 
first or ortho series, the hydrogen atoms in benzol being num- | 
bered in regular succession, they are replaced in the same regular 
succession. In the second or meta series, the order is 1, 2, 3, 5, 
&c., whilst the third or para series take open order as I, 2, 4, 5. 
Thus we have :— 
Ortho Series. Para Series, Meta Series. 
«_{Mellitic or ce = 
C,, Hs O12 Hexeabasic) p enzolhexacarbonic. 
C,; H6 O;. Penta . 
C,, He Og Tetra. . 
J Unknown. _ - 
\Pyromelliticor | Isopyromellitic. Unknown. 
\ Benzoltetracarbonic. 
{Trimesinic, or 
CoH, O, Tri. . . \Benzolirieirbonic: Hemimellitic. Trimellitic. 
CgHeO4,Di .. . Helslicior ot # Isophtalic. Tetraphtalic. 
| Benzoic or _ = 
C7 Hs 0, Mono . « \Benzol Monocarbonic. 
Amongst the most interesting series of new organic bodies are 
those in which tetrad silicon partly replaces carbon. Our 
knowledge of these substances is gradually becoming more com- 
plete ; the last new member prepared by Friedel and Ladenburg 
is silico-propionic acid C, H, Si O, H, the first of a series of 
carbo-silicic acids containing the radical Si O, H. 
The interesting researches of Matthiessen and Wright on 
Morphine and Codeine have thrown a new light on the constitu- 
tion of these opium alkaloids. Treated with hydrochloric acid, 
morphine loses one molecule of water, and gives rise to a new 
base, called ap»morphine. Thus : 
Cy7 yy NO; = H, O + Ci; My, NO, 
Morphine. Apomorphine. 
which differs in a remarkable manner from morphine, both in its 
chemical and physiological actions, being soluble in alcohol, ether, 
and chloroform, whereas morphine is nearly insoluble, and act- 
ing as the most powerful emetic known, 75th of a grain producing 
vomiting in less than ten minutes. Codeine, which only differs 
from morphine by CHg, also yields apomorphine on treatment 
at a high temperature with hydrochloric acid, methylchloride 
being at the same time eliminated. 
An important application of the dehydrating and carbon con- 
densing power of zinc chloride, long known in its action on al- 
cohol to produce ether, has been made by Kekule in the redupli- 
cation of aldehyde to form croton-aldehyde with loss of water. 
2(C, H, 0) — Hy O= €, H, 0: 
This croton-aldehyde is also probably formed as an intermediate 
product in the manufacture of chloral from aldehyde, and gives 
rise to the formation of crotonchloral 
C; Hy ClO: 
The discovery of the sedative properties of chloral-hydrate 
by Liebreich marks an era in medical chemistry second 
only to the discovery of the anzsthetic properties of 
chloroform. Chloral not only combines with water to form a 
solid hydrate, but also forms solid alcoholates ; but the se bodies 
appear to possess quite different medicinal properties from the 
hydrate, and it is important that no alcoholate should be present 
in the officinal preparation. The chemistry of colouring matters 
has lately received an enormous impetus in the working of the 
brilliant discovery of the production of artificial alizarine, the 
colouring matter of madder, by Messrs. Graebe and Liebermann. 
This discovery, announced at our last meeting, is of the highest 
importance, whether we regard its scientific interest or its prac- 
tical and commercial value, and it differs from all the former 
results which have been brought about by the application of 
science to the production of colouring matters, inasmuch as this 
has reference tu the artificial production of a natural vegetable 
colouring substance which has been used as a dye from time 
immemorial, and which is still employed in enormous quantities 
for the production of the pink, purple, and black colours 
which are seen everywhere on printed calicoes, During the 
past year much progress has been made in the practical 
working of the processes by which this colouring matter is 
obtained from the hydrocarbon anthracene contained in coal tar, 
and new and more economical plans for effecting the transfor- 
mation have been independently proposed by Perkin and Caro, 
and Schorlemmer and Dale. The theoretical investigation of 
the reaction, and especially of the nature of some other peculiar 
products formed in addition to alizarine, which render the arti- 
ficial colouring matter different from natural alizarine, has been 
carried out by Mr. Perkin, and especially by Dr. Schunck. As 
we are promised papers on this subject from both these gentle- 
men, I need not now enter further into these interesting questions, 
The surest proof of perfection in a manufacture is the degree 
in which the waste products are utilised, and in which the pro- 
cesses are made continuous. One by one the imperfections of 
the original discovery are made to disappear, and the products 
which were wasted become sources of profit, whilst in many 
cases their utilisation alone renders possible the continuance of 
the manufacture in the midst of a rapidly increasing district. 
The Section will have the opportunity of inspecting the practical 
working of at least two of the most valuable of these new 
processes which have lately been introduced into our most 
important chemical manufacture, that of alkali. The first of 
these has been at work for some time ; it is that of the recovery. 
of sulphur from the vat waste, that dé/e notre of the alkali 
makers and of their neighbours. Dr. Mond has now, I be- 
lieve, satisfactorily solved the difficult problem of economically 
regaining the sulphur by oxidising the insoluble monosulphide 
of calcium in the lixiviating vat itself to the soluble hyposulphite, 
and decomposing this by hydrochloric acid, when all the sulphur 
is deposited as a white powder. 
The second of these discoveries relates to the recovery or 
regeneration of the black oxide of manganese, used for the evo- 
lution of chlorine in the manufacture of bleaching powder. This 
subject has long attracted the attention of chemists, and a 
feasible though somewat costly process, that of Dunlop, has been 
at work for some time at Messrs. Tennant’s works at St. Rollox. 
During the last year a very beautifully simple and economical 
process, proposed by Mr. Weldon, and first successfully carried 
out on a practical scale in Messrs. Gamble’s works at St. 
Helen’s, has quickly obtained recognition, and is now worked 
by more than thirty-seven firms throughout the kingdom. The 
principle upon which this process depends was explained by Mr. 
Weldon at the Exeter meeting. It depends on the fact that 
although when alone the lower oxides of manganese cannot be 
oxidised by air and steam under the ordinary pressure to the state 
of dioxide, yet that this is possible when one molecule of lime 
is present to each molecule of oxide of manganese. The man- 
ganous oxide is precipitated from the still liquors with the above 
excess of lime, and by the action of steam and air on this a 
black powder consisting of a compound of manganese, dioxide and 
lime, Mn O, C, O, or calcium manganite, is formed. This, 
of course, is capable of again generating chlorine, on ad- 
dition of hydrochloric acid, and thus the chlorine pro- 
cess is made continuous with a working loss of only 2% per 
cent. of manganese. The Section will have the advantage of seeing 
Mond’s process at work at Messrs. Hutchinson and Weldon’s 
process, at Messrs. Gaskell, Deacon, and Co.’s, at Widnes. 
A third process, which may possibly still further revolutionise 
the manufacture of bleaching powder, is the direct production of 
chlorine from hydrochloric acid without the use of manganese 
at all. In presence of oxygen and of certain metallic oxides, 
such as oxide of copper, hydrochloric acid gas parts at a red 
heat with all its hydrogen, water and chlorine being formed. 
This interesting reaction is employed by Mr. Deacon for the 
direct manufacture of bleaching powder from the gases issuing 
directly from the salt-cake furnace. Air is admitted together 
with hydrochloric acid gas, and the mixture is passed over red- 
hot bricks impregnated with copper salt. The oxide of copper 
acts as by contact and remains unaltered, whilst the chlorine, 
watery vapour, and excess of air pass at once into the lime- 
chamber. The difficulty in this process-is the large volume 
of diluting nitrogen which accompanies the chlorine, but I 
believe we shall hear from Mr. Deacon that, notwithstanding this 
drawback, he has accomplished his end of making good bleach- 
ing powder by this process. 
CONTENTS Pace 
Tue MusevuMS AND SCIENTIFIC INSTITUTIONS OF LIVERPOOL . . . 389 
Norrs oN THE GEOLOGY OF THE COUNTRY AROUND LivERPOOL. By 
GDP IDE TRANCE: pi car ie: sD pan apie 0 to! aise a a 
Tue Seconp ProvinciAL MEETING OF THE IRON AND STEEL InsTI- 
TUDE. JBy JOHN -MAVER <.¢-) - Unytiey c) ted cow (oe) a ie 
LETTERS TO THE Epiror . FF i cir MT ee Tele OWI 9 ii Piney 390 
GrotocicaL Discovery In LiveRPooL. By J, P. EARWAKER . . + 397 
NOTES Lis fj sot -s) , aiagge> dee an Lb eB ee Dante wees ate ae nee 
Tue Britisu AssociaTION.—LIvERPOOL MEETING, 1870. . - » » 399 
Address of Thomas Henry Huxley, LL.D., F.R.S., President. . 400 
Professor H. E, Roscoe’s Opening Address to Section B. . . 2 408 
