object is not to explain phenomena by reducing them under laws, but to give rules for attaining certain ends. Hence all sound methodologists would term it a text-book, not of science, but of art.

attract to itself many who now hold aloof. But, for some reason, this course has not recommended itself to the senior Fellows, and at the last meeting, on the 18th inst., the President, speaking on their behalf, strongly advised that the practice should be discontinued.

Many of those who, like myself, heard that speech must have been deeply pained to hear from the President of the Chemical Society, and that President Prof. Abel, that a strictly chemical qualification" ought not to be required for its Fellowship.

The first chapter of the work gives a summary of acts of Parliament and other regulations affecting railways. Upon this follow in succession chapters on the permanent way, on points and crossings; on signals, on the block system, on stations, and on rolling-stock. The important" subject of signals, we may here remark, is receiving at present an increased amount of attention, in part probably owing to the lamentable Huntingdon collison. The fact that a sudden and violent snow-storm, which, after all, is a possible occurrence at any time during the five or six months of the year, may at any time cause the signal for "danger" or for "caution" to be interpreted as "safety" and allure a train to the destruction of its inmates. Nor is this all; red or green lights produced by the interposition of coloured glasses between a lamp and the eye of an observer are exceedingly reduced in their illuminating power. Hence the question arises whether colour should not be altogether discarded, and whether the number and the position of the lights exhibited might not be made available. Thus a single light might express safety, two in a perpendicular line denoting caution, and three standing for danger.

The author seems somewhat sore on the subject of danger on railways. He "regards as a popular error the supposition which is from time to time advanced that railway engineers and managers are, as a body, remiss in attention to the safety or convenience of the public. From personal experience he can vouch for the care, foresight, and anxiety which are bestowed on these subjects by those in charge of our railways." We are delighted to hear it, and hope that some day all this "care, foresight, and anxiety " will begin to bear a little fruit.

This work, to the best of our knowledge, takes up ground previously unoccupied, and we have no doubt that it will be found highly useful by such as are likely to be engaged in the construction or management of railways.

CORRESPONDENCE.

THE CHEMICAL SOCIETY.

To the Editor of the Chemical News. SIR,-One would properly expect, from its very name, that the Chemical Society was an association of chemists for the advancement of chemistry, and it would be natural to think that its Fellows were chemists.

Need I say, Sir, that such is not at present the case with the Chemical Society of London. By the indiscriminating admission in times past of all candidates, it has at last reduced itself to its present state-not a body of chemists, but a motley mixture of all kinds of dabblers in science, and often, alas! very often, not even that. It was only to be expected, and the present relations of the Society to the profession too plainly show it to have been so, that it would soon alienate from itself all real chemists, and cease to represent the chemistry of this country.

Recently awakened to the fact that their Society was in disgrace and was begun to be held in derision, and almost in contempt, even by themselves, a number of the Fellows have for some time past steadily refused to admit any but those who show unmistakable evidence of chemical attainments, and so at each successive meeting a larger and larger proportion have been blackballed, until, last meeting but one, two-thirds of the candidates were rejected.

It appeared as if, at last, there were some hope of the Chemical Society making its Fellowship worth the having -it appeared likely to regain its chemical prestige and

No doubt Prof. Abel, like ourselves, has the prosperity of the Chemical Society at heart, but while he seeks it in large numbers without much regard to quality, we see its best interest in a high standard of fellowship, by which the dignity of the Society may be so raised that many would be drawn into it who now hold back in disdain. Upon this point, whether the numbers of the Society will be lessened, the opposition turns, and as there does not appear any reason to fear falling off in this respect, it is to be hoped they will adopt the view that the attractiveness off the Society will increase with the standard of qualification required, and heartily join the movement.

It has been admitted by all, even by Prof. Abel and his colleagues, that something must be done to raise the chemical profession out of its present deplorable condition. It must be organised; either the Chemical Society must be made a society of chemists indeed, or some new body, representing the profession, must be founded, such as the "Institute of Professional Chemists" now under consideration. Then I, for one, will not care who is admitted to the Chemical Soeiety, but until then, and so long as the F.C.S. is considered to indicate chemical abilities, so long must the gates of the Chemical Society be closely guarded.

"Sculptor," "Artist," "Clerk in Holy Orders," "B.A.," "B.Sc."-vaguest of all-"Science Teacher;" these, forsooth, are the qualifications stated by candidates on their papers. What must they think of the Chemical Society! What must be their respect for it!

In conclusion, I sincerely hope that the Fellows will continue to exercise more and more care in electing candidates, and they may then hope to have a society commanding the respect of chemists.-I am, &c.,

NUNTIUS.

BLACKBALLING AT THE CHEMICAL SOCIETY.

To the Editor of the Chemical News. SIR,-On the 4th instant, six out of nine candidates for admission to the Chemical Society were rejected by its Fellows. On the 18th (the last meeting of the Society) the President condemned this act in language which, to say the least, was injudicious, and which most certainly would have been received in a different spirit had it not been for the great respect entertained for the speaker. In brief, it was intimated that the Fellows ought not to use their individual judgment, and that the blackballing was indiscriminate. If this latter be true, it is a grievous fault and calls for immediate rectification. I take it that the qualification required for the Fellowship of the Chemical Society is a chemical one, and a chemical one only. If candidates fail to state this briefly, clearly, and truthfully they, and they alone, are responsible for their non-election. A sculptor or artist may justly aspire to the membership of the Royal Academy; an M.D. to the membership of one or more of the Medical Societies; and a D.Sc. to the membership of a Society for the Propagation of General Knowledge. But as these are not chemical qualifications, the man who offers these and these alone insults the Chemical Society, and should, in consequence, be unanimously rejected. Had the President sought for the real cause of the independent action of which he complained, he would have found it in the profound distrust which the majority of the working Fellows of the Society have for those who should be their profes

. sional leaders, men who, with few exceptions, seldom attend their meetings, and yet, being leaders of their Society, systematically sacrifice the British chemist and British chemistry, simply to increase the number of Fellows, and thus give to the Society of which they are the nominal heads a fictitious importance.-I am, &c.,

NOTE.-All degrees of temperature are Centigrade, unless otherwise corresponding to the formula C6H7O7, or to one of its

Black Inks.-M. E. H. Viedt.-A very long memoir, giving a full account of the manufacture of black inks.

Manufacture of Extract of Indigo.-M. Max Roesler. -An interesting paper, too long for insertion? The author dissolves the indigo in a mixture of 9 parts fuming sulphuric acid to 2 of the common monohydrated acid. He takes 500 grms. of dry powdered indigo to 24 kilos. of mixed acid, and he adds the acid by two equal successive portions to the indigo.

History of the Manufacture of Turkey-Red.Theodore Chateau.-A continuation.

Report on the Process of Faure and Kessler for he Manufactute of Sulphuric Acid.-Already noticed.

The Loan Collection at South Kensington.-The conferences in connection with the Loan Collection of Scientific Apparatus at South Kensington have been highly successful. In an early number we shall give

The peculiarity of its properties seems due to a very small abstracts of the papers contributed to the Chemical quantity of benzino-sulphate of potassa.

Section, which was opened on Thursday, the 18th inst., by

an address from the President, Dr. Frankland, F.R.S.,
Dr. J. H. Gilbert delivered an address on "Some Points
Connected with Vegetation;" Mr. W. F. Donkin described
Sir Benjamin Brodie's ozone apparatus; and Prof.
Andrews gave an account of his investigations on the
physical constitution of gases.
The second and final
meeting of the Section was on Tuesday last, when Dr.
Frankland read an important communication from M.
Frémy on the Diminution of Scientific Research. Ad-
dresses were also delivered by Prof. Roscoe, "On
Vanadium and its Compounds;" by Prof. Guthrie," On
Cryohydrates and Water of Crystallisation;" by Prof.
Williamson, "On the Manufacture of Steel;" by Mr. W.
C. Roberts, " On the Apparatus used by the late Prof.
Graham in his Researches ;" by Mr. W. N. Hartley, "On
Liquid Carbonic Acid in the Cavities of Crystals;" and
by Prof. Gladstone, "On the Electrolysis of Organic
Compounds with the Copper-Zinc Couple."

PATENTS.

ABRIDGMENTS OF PROVISIONAL AND COMPLETE
SPECIFICATIONS.

possible, because the purer the anthracen the less sulphuric acid is required for its perfect solution. The quantity of sulphuric acid varies if the ordinary concentrated acid is used. from between 10 to 20 parts of the weight of anthracen used, if fuming acid be employed, from between 3 to 10 parts of the weight of anthracen. The resulting liquid has to be dissolved in about fifteen to twenty times of its volume of water and neutralised with caustic lime or carbonate of lime. After filtration, the liquid, which contains now the lime salts of what I call the sulpho-acids of anthracen. is precipitated with carbonate of soda. The soda salts of the above sulpho-acids received in this way are heated with two to three times their weight of caustic soda or potash, or a mixture of both, in a suitable vessel to a temperature from between 180° to 260° C. until, in dissolving a portion of the fused mass in boiling water, the colour ceases to become more intense. The fused mass is then dissolved in boiling water, and precipitated with hydrochloric, or sulphuric, or any other convenient acid. The precipitate is collected on a filter, washed with water, and is then suitable for use in dyeing and printing, in the same manner as preparations of madder. Improvements in filtering and purifying water. O. V. Morgan' Kensington, Middlesex, and G. R. Moelchaerek, Battersea, Surrey

February 20, 1875.-No. 625. This invention consists in the special use of calcium carbonate in addition to or in combination with other filtering media, either as forming part of the filter or in the form of cups or vessels to be used in conjunction with filters of any description, or by themselves, more particularly for the purpose of removing lead from its solution in water to be filtered.

MEETINGS FOR THE WEEK.

SATURDAY, 27th.-Physical, 3. "On Selective Absorption," by W.
Ackroyd. "On an Atmospheric Phenomenon in
Ceylon," by Rev. R. Abbay.
"The De-

Improvements in the production of ammonia. A. M. Clark, Chancery Lane, Middlesex. (A communication from F. Maxwell-Lyte. Paris.) February 16, 1875.-No. 563. The invention consists in the special reaction of nascent hydrogen produced in presence of a triad or pentad element and nitrogen for the production of ammonia by synthesis of TUESDAY,

its elements.

Improvements in filters and percolators. W. B. Gething, Fleet Street, London. February 16, 1875.-No. 566. I form the body of the filter or percolator in the form of an inverted cone, into the bottom of which I insert or place a piece of perforated metal or other material to act as a strainer to the said filter or percolator. I place a metal cover with screw-cap inserted, and at the bottom of the said filter I put a funnel, so that it can be put into a bottle or other narrow mouthed vessel. The said filter or percolator may be made of tinned iron or other metal, and japanned or otherwise ornamented to protect it from damage or corrosion. The advantages I claim are that it (the filter) will always keep the liquor free from dust or dirt or evaporation while in process of filtration.

Improvements in the method or means employed in treating and clarifying sewage or other impure waters. S. Hallsworth, Armley, and R. Bailes, Woodhouse Carr, both near Leeds, York. February 17, 1875.-No. 573. First mixture-Copperas, dry copperas, copperas bottoms, copperas sediment, the sediment that subsides from manufacture of nitrate of iron, the spent residue of iron pyrites, also spent pyrites. Second mixture-Spent residue of iron pyrites, iron ore or slag saturated with liquor from beds of iron pyrites at copperas works, or with diluted sulphuric, or muriatic, or diluted nitric acid. The sewage or other matter is run into tank, to which is added slacked lime or gas-lime, clarifying mixture No. 1, or mixture No. 2; the whole is agitated, allowed to settle, and the pure water run off.

An improved process and apparatus for treating vegetable substances for the extraction of fatty matter, and for the manufacture of spirits and fermented liquids. A. Manbré, Baker Street, Portman Square, Middlesex. February 17, 1875.-No. 579. My improved process is for extracting the fatty matter contained in fruits, cereals, seeds, nuts, roots, and other vegetable substances containing fatty, starchy, or saccharine matters, thereby freeing the starchy and saccharine matters from the fatty matter, and rendering them more suitable for the production of purer and better flavoured spirit and wine, beer, and other fermented beverages.

Improvements in the manufacture of steel. J. Noad, Richmond House, Plaistow, Essex. February 18, 1875.-No. 592. This Provisional Specification describes taking iron or steel obtained by a process of chemical deposition, and placing a small quantity of such iron or steel in a crucible, and pouring upon it cast-iron or other metal melted in a cupola furnace, so as to fill the crucible. The crucible is then closely covered, and the metal is maintained at a high temperature for some time, and then cast into ingots.

A new process for bronzing or giving a metallic appearance to textile fabrics. W. Thackrah, Dewsbury, York. February 19, 1875.No. 608. The novelty of the invention consists in producing upon piled fabrics, which have been previously dyed, a bronzed or metallic appearance by chemical agency, viz., subjecting such fabrics to various baths composed of tannic acid, picric acid, and then a solution of nitrate of tin and muriate of copper. Finally, the fabrics are boiled in a solution of aniline.

Improvements in the manufacture of colouring matter_suitable for dyeing and printing. A. Kottgen, Old Broad Street, London. (A communication from A. Gauhe, Barmen Eitorf, Rhenish Prussia.) February 20, 1875.-No. 619. The process consists in heating the substance known to chemists under the name of anthracen with concentrated or fuming sulphuric acid to a temperature from between 240° to 260° C. until, in diluting a small portion of it with water, no more precipitate is produced. The anthracen used should be as pure as

(African Section). velopment of Central Africa," by Edward Hutchinson.

30th.-Society of Arts, 8.

Royal Institution, 3. "Wheatstone's Discoveries," by Prof. W. G. Adams.

THURSDAY, June 1st.-Royal Institution, 3. "On Voltaic Electricity," by Prof. Tyndall, D.C.L., LL.D., F.R.S. Royal, 4. Election of Officers.

Royal, 8.30.

Royal Society Club, 6.30.

Chemical, 8. "On Hematine and Phosphorised
Compounds contained in Blood Corpuscles," by
Dr. Thudichum and Mr. Kingzett. "On the
Liquid Carbon Dioxide from Different Sources,"
by W. N. Hartley. "Note on the General Appli-
cability of Frankland and Armstrong's Combus-
tion Method to the Estimation of Carbon and
Nitrogen in Organic Compounds," by Dr. Thudi-
chum and Mr. Kingzett. "(I.) On Peroxides;
(II.) On the Estimation of Nitrogen; (III.) On
Chromic and Perchromic Acids," by Thomas
Fairley. "On Aluminium Nitride," by Prof.
Mallet. "Chemical Studies," by Prof. Dewar.
"On the Volumetric Estimation of Mercury," by
Prof. Tuson and Mr. Neison.

FRIDAY, 2nd.-Royal Institution, 9. "Recent Discoveries about
Vanadium," by Prof. Roscoe.
Geologist's Asociation, 8.

SATURDAY, 3rd.-Royal Institution, 3. "On King Arthur's Place in
English Literature," by Prof. Morley.

AI

New Edition, in small 8vo., with 66 Woodcuts, price 6s. IR AND ITS RELATIONS TO LIFE, the substance of a Course of Lectures delivered at the Royal Institution of Great Britain in 1874, with some Additions. By WALTER NOEL HARTLEY, F.C.S., Demonstrator of Chemistry at King's College, London. Second Edition, revised.

"Written in ordinary language, and in a very clear style, this book contains an account of all that has been done in the way of scientific research on the relation of air to life."-Nature.

"We recommend this volume to all who are desirous of being correctly informed on the chemical, and to some extent the physical, conditions of the atmosphere in which we live."-Athenæum.

London: LONGMANS and CO.

UNIVERSITY OF LONDON.

Notice is hereby given, that the next Half

Yearly Examination for MATRICULATION in this University will commence on MONDAY, the 26th of JUNE, 1876. In addition to the Metropolitan Examination, Provincial Examinations will be held at St. Cuthbert's College, Ushaw; Stonyhurst College; St. Stanislaus College, Tullamore; Owens College, Manchester; Queen's College, Liverpool; and Queen's College, Birmingham.

Every Candidate is required to transmit his Certificate of Age to the Registrar (University of London, Burlington Gardens, London, W.) at least fourteen days before the commencement of the Examination. WILLIAM B. CARPENTER, M.D., Registrar,

May 22nd, 1876.

THE CHEMICAL

VOL. XXXII. No. 862.

with the tetrad carbon. We thus see how in so many of

NEWS.ist compounds cyanogen acts as a monad exactly

ON THE CLASSIFICATION OF THE

CYANOGEN COMPOUNDS.

By SYDNEY LUPTON, M.A.

In a suggestive paper published in the CHEMICAL NEWS (vol. xxxiii., p. 141) Mr. Skey calls attention to the present state of our knowledge of the relationships of cyanogen, and draws the conclusion that it is far more nearly similar in its properties to oxygen than it is to chlorine. It may be of value to attempt to classify a few of the more important cyanides and then to examine the arguments brought forward by Mr. Skey.

From the intimate connection between the various members of the cyanogen group, they are, in general, considered together as a separate section of organic chemistry. In a general review of these bodies the first thing which strikes us is the large number of compounds in which CN plays the part of a simple monatomic element; the second is the numerous complicated compounds containing the group CN more than once. Considering, then, the cyanogen compounds as a group to themselves, it is evidently of advantage to use as our means of classification the groups CN, and not, as is usually the case, the various bodies with which it may happen to be combined; just as the paraffins, for example, are classified by the number of atoms of carbon which they contain. Our next step is to enquire into the constitution and combining powers of the group CN on which our classification is to be based.

Carbon is in almost all its compounds a tetrad, e.g., CH4, CCl4, &c.; it is, however, sometimes a dyad CO. Again, carbon may saturate some of its affinities by combining with itself C2H5C1,C2H4, &c.

Nitrogen in many of its combinations plays the part of a pentad NH4Cl, NH2(CH3) HBr, &c., in others it acts as a triad NH,N(CH3)3, &c.; in one of its combinations, NO, it is apparently a dyad, and in another, NOH, a monad. Like carbon it possesses considerable power of self-saturation. From the more general valencies of carbon and nitrogen we should expect cyanogen to be tetradic carbon combined with either pentadic or triadic nitrogen. There was considerable doubt as to which of these formulæ belonged to cyanogen until Dr. Hofmann's brilliant discovery of the iso-cyanides, bodies clearly belonging to the former class. They are formed by distilling a mixture of an alcoholic ammonia base and chloroform with alcoholic potash

C6H4N+CHCl3=3HC1+C6H5.N.C.

The iso-cyanides are scarcely acted on by alkalies, but break up under the action of acids into formic acid and an

alcoholic ammonia

C6H NC+2H2O=C6H5NH2+H2CO2.

analogous to chlorine.

But further, just as we find nitrogen combining with itself in the oxides of nitrogen and in the azo-phenyl compounds; and as we find carbon combining with itself to form the connecting link of an organic body, so we may consider that cyanogen combines with itself to give us the more complicated cyanides; and as the addition of each atom of carbon makes an addition of two to the saturation-power of a molecule, so the addition of each group CN causes the addition of one to the saturationpower of the molecule.

It is of course possible that the addition of the cyanogen groups takes place by the combination of the two selfsaturated atomicities of nitrogen, and this may account for certain instances of isomerism, e.g., paracyanogen ; but this point we have at present no means of deciding. strictly belonging to the cyanogen group, we may arrange Leaving out of consideration the iso cyanides as not the cyanogen compounds into different classes as they contain once, twice, three times, &c., the group CN'=Cy'; thus we have :

(Cy1)' (Cya)" (Cy3)'''(Cy4)'''', &c.

By this of course we entirely throw over the system of types, and classify by valencies which are in reality at the root of that system. What is the so-called water type but two monad groups each united to one dyad group, and so on for the other types? It must be admitted that in several cases this method of classification places divisions where perhaps there ought to be none, e.g., between and zinc cyanide; but I venture to hope that it is at least melamine and melam, and between potassium cyanide no worse in this respect than any other system of classification which has been proposed.

Many of the cyanogen compounds are so difficult to examine that the difficulty of the classification consists as yet in their true empirical formula, and this can only be overcome by a very extended series of accurate analyses, e.g., the nitroprussides. We know of cyanogen compounds which contain the group CN from 1 to 18 times, but many of the intermediate groups are still wanting.

It may be of interest to arrange the more important of the cyanides of organic bodies, as they are, in general, cyanides under their respective classes, putting in but few simple and would cause useless repetition. Monocyanides (Cy1)'. CyH, prusssic acid CyCH3, methyl cyanide CyAg, silver cyanide Cy K, potassium cyanide

CyNH4, ammonium cyanide
CyCy, cyanogen
CyCl, cyanogen chloride

CyBr, cyanogen bromide
CyI, cyanogen iodide

CyNH2, cyanamide
CyOH, cyanic acid
CyOK, potassium cyanate
CyONH4, ammonium cyan-

ate

CyOC2H5, ethyl cyanate
CySH, sulphocyanic acid
CySK, potassium sulpho-
cyanide

CySNH4, ammonium sul-
phocyanide

The three chief groups contained in this class are the cyanides of monatomic radicals, the cyanates, and the

Under similar conditions ordinary phenyl-cyanide breaks sulphocyanates. Cyanogen itself being the means of into prussic acid and phenyl-chloride

up

CNCsH5+HC1=CH,+CNH. Further confirmation of this view that cyanogen consists of tetradic carbon and triadic nitrogen is afforded by M. Gaultier's and Gal's discovery of the hydro-chlorates, hydro-bromates, and hydriodates of the cyanides and cyanates. In these bodies evidently the two atomicities of nitrogen previously saturated by one another are now saturated by hydrogen and chlorine, &c., just as we have ammonia and its congeners forming the ammonium salts. In the great majority of the cyanogen compounds we may leave out of consideration the fact that nitrogen is a pentad, and regard it simply as a triad in combination

classification ought possibly not to appear in this list, but it is put in for the sake of uniformity. The double cyanide and nitride of titanium presents many points of difficulty; it possibly belongs to this class, its formula being written Cy [Ti(TIN)3'], but further analyses are wanting to establish its formula conclusively.

Dicyanides (Cy2)".
Cy2Cl2(?),cyanogen chloride
Cy2KAg, silver and potas-
sium cyanide
Cy,Cu, cupric cyanide
Cy2Cu2, cuprous cyanide

Cy2(OH)2, dicyanic acid
Cy2Se, cyanogen selenide

Cy2S, cyanogen sulphide
Cy HSH, cyanogen sulphy.
drate

Cу12 Fe2H6, hydrogen ferricyanide
Cy12Fе2K6, potassium ferricyanide
Cy12 Fe2Ca3, calcium ferricyanide

Cy12 Fe2Ni(NH3ni)2, nickelic nickelammonium ferricyanide
Cy12Fe2K3Na3, potassium and sodium ferricyanide
Cy12Fe2Ag6.3NH3, ammonio-silver ferricyanide
Cy12Fez Fez, ferrous ferricyanide

Cy12Fe4, ferric ferricyanide (Prussian green)
Cy12C02K6, potassium cobalto-cyanide

Cy12Mn2K6, potassium manganic cyanide

Cy12Cr2K6, potassium chromicyanide