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British Association. The President's Address.

CHEMICAL NEWS,

Sept. 8, 1876. be regarded as in any way hostile to the literary studies, , of scientific teaching; and students attracted to them from and especially to the ancient classical studies, which have all countries became enthusiastically devoted to science, always been so carefully cherished at Oxford. If, indeed, while they learned its methods from example even more there were any such risk, few would hesitate to exclaim-than from precept. Will anyone have the courage to Let science shift elsewhere for herself, and let literature assert that organic chemistry, with its many applications and philosophy find shelter in Oxford ! But there is no to the uses of mankind, would have made in a few short ground for any such anxiety. Literature and science, years the marvellous strides it has done if Science, now philosophy and art, when properly cultivated, far from as in mediæval times, had pursued her work in stria opposing, will mutually aid one another. There will be seclusion,ample room for all, and, by judicious arrangements, all

Semota ab nostris rebus, seiunctaque longe, may receive the attention they deserve.

Ipsa suis pollens opibus, nil indiga nostri? A University, or Studium Generale, ought to embrace But while the Universities ought not to apply their rein its arrangements the whole circle of studies which in- sources in support of a measure which would render their volve the material interests of society, as well as those teaching ineffective, and would at the same time dry up which cultivate intelle&ual refinement. The industries of the springs of intellectual growth, they ought to admit the country should look to the Universities for the develop- freely to university positions men of high repute from other ment of the principles of applied as well as of abstract universities, and even without academic qualifications. science; and in this respect no institutions have ever had An honorary degree does not necessarily imply a univer. so grand a possession within easy reach as have the uni- sity education; but it if have any meaning at all, it implies versities of England at this conjuncture, if only they have that he who has obtained it is at least on a level with the the courage to seize it. With their historic reputation, ordinary graduate, and should be eligible to university their collegiate endowments, their commanding influence, positions of the highest trust. Oxford and Cambridge should continue to be all that they Not less important would it be for the encouragement now are; but they should, moreover, attract to their of learning throughout the country that the English Uniledure halls and working cabinets students in large num-versities, remembering that they were founded for the bers preparing for the higher industrial pursuits of the same objects, and derive their authority from a common country. The great physical laboratory in Cambridge, source, should be prepared to recognise the ancient Unifounded and equipped by the noble representative of the versities of Scotland as freely as they have always recogHouse of Cavendish, has in this respect a peculiar sig. nised the Elizabethan University of Dublin. Such a meanificance, and is an important step in the direction I have sure would invigorate the whole university system of the indicated. But a small number only of those for whom country more than any other I can think of. It would this temple of science is designed are now to be found in lead to the strengthening of the literary element in the Cambridge. It remains for the University to perform its northern, and of the practical element in the southern part, and to widen its portals so that the nation at large universities, and it would bring the highest teaching of the may reap the advantage of this well-timed foundation. country everywhere more fully into harmony with the re

If the Universities, in accordance with the spirit of their quirements of the times in which we live. As an indirect statutes, or at least of ancient usage, would demand from result, it could not fail to give a powerful impulse to the candidates for some of the higher degrees proof of literary pursuits as well as to scientific investigations. original powers of investigation, they would give an im- Professors would be promoted from smaller positions in portant stimulus to the cultivation of science. The ex- one university to higher positions in another, after they ample of many Continental Universities, and among had given proofs of industry and ability; and stagnation, others of the venerable University of Leyden, may here be hurtful alike to professorial and professional life, would be mentioned. Two proof essays recently written for the effe&tually prevented. If this union were established degree of Doctor of Science in Leyden, one by Van der among the old universities, and if at the same time a new Waals, the other by Lorenz, are works of unusual merit; university (as I myself ten years ago earnestly proposed) and another pupil of Professor Rijke is now engaged in were founded on sound principles amidst the great populaan elaborate experimental research as a qualification for tions of Lancashire and Yorkshire, the university system the same degree.

of the country would gradually receive a large and useful The endowment of a body of scientific men devoted ex-extension, and, without losing any of its present valuable clusively to original research, without the duty of teaching characteristics, would become more intimately related or other occupation, has of late been strongly advocated than hitherto with those great industries upon which in this country; and M. Fremy has given the weight of mainly depend the strength and wealth of the nation. his high authority to a somewhat similar proposal for It may perhaps appear to many a paradoxical assertion the encouragement of research in France.' I will not to maintain that the industries of the country should look attempt to discuss the subject as a national question, the to the calm and serene regions of Oxford and Cambridge more so as after having given the proposal the most care for help in the troublous times of which we have now a ful consideration in my power, and turned it round on sharp and severe note of warning. But I have not spoken every side, I have failed to discover how it could be worked on light grounds, nor without due consideration. If Great so as to secure the end in view.

Britain is to retain the commanding position she has so But whatever may be said in favour of the endowment long, occupied in skilled manufacture, the easy ways of pure research as a national question, the Universities which (owing partly to the high qualities of her people, ought surely never to be asked to give their aid to a measure partly to the advantages of her insular position and which would separate the higher intellects of the country mineral wealth) have sufficed for the past will not be found from the flower of its youth. It is only through the influe to suffice for the future. The highest training which can ence of original minds that any great or enduring im- be brought to bear on practical science will be imperatively pression can be produced on the hopeful student. With required; and it will be a fatal policy if that training is to out original power, and the habit of exercising it, you may be sought for in foreign lands because it cannot be obtained have an able instructor, but you cannot have a great at home. The country which depends unduly on the teacher. No man can be expected to train others in habits stranger for the education of its skilled men, or neglects of observation and thought he has never acquired himself. in its highest places this primary duty, may expect to find In every age of the world the great schools of learning the demand for such skill gradually to pass away, and have, as in Athens of old, gathered around great and along with it the industry for which it was wanted. I do original minds, and never more conspicuously than in the not claim for scientific education more than it will accom. modern schools of chemistry, which reflected the genius of plish, nor can it ever replace the after-training of the Liebig, Wöhler, Bunsen, and Hofmann. These schools workshop or factory. Rare and powerful minds have, it is have been nurseries of original research as well as models true, often been independent of it; but high education

, } British Association. The President's Address. Sept. 8, 1876.

103 always gives an enormous advantage to the country where been kept steadily in view by this Association, and the it prevails. Let no one suppose I am now referring to valuable Reports, which are a monument to the industry elementary instruction, and much less to the active work and zeal of its members, embrace every part of the dowhich is going on everywhere around us, in preparing for main of science. It is with the greater confidence, thereexaminations of all kinds. These things are all very use fore, that I have ventured to suggest from this Chair that ful in their way, but it is not by them alone that the practi- no partition-wall should anywhere be raised up between cal arts are to be sustained in the country. It is by pure and applied science. The same sentiment animates education in its highest sense, based on a broad scientific our vigorous ally, the French Association for the Advance. foundation, and leading to the application of science to ment of Science, which rivalling, as it already does, this practical purposes—in itself one of the noblest pursuits of Association in the high scientific character of its prothe human mind that this result is to be reached. That ceedings, bids fair in a few years to call forth the same education of this kind can be most effectively given in a interest in science and its results, throughout the great university, or in an institution like the Polytechnic School provincial towns of France, which the British Association of Zürich, which differs from the scientific side of a uni- may justly claim to have already effected in this country, versity only in name, and to a large extent supplements No better proof can be given of the wide base upon the teaching of an actual university, I am firmly convinced; which the French Association rests than the fact that it and for this reason, among others, I have always deemed was presided over last year by an able representative of the establishment in this country of Examining Boards commerce and industry, and this year by one who has with the power of granting degrees, but with none of the long held an exalted position in the world of science, and higher and more important functions of a university, to has now the rare distinction of representing in her historic have been a measure of questionable utility. It is to Academies the literature as well as the science of Oxford and Cambridge, widely extended as they can France. readily be, that the country should chiefly look for the Whatever be the result of our efforts to advance science development of practical science; they have abundant re- and industry, it requires no gift of prophecy to declare sources for the task, and if they wish to secure and that the boundless resources which the supreme Author strengthen their lofty position, they can do it in no way and Upholder of the Universe has provided for the use of so effectually as by showing that in a green old age they man will, as time rolls on, be more and more fully applied preserve the vigour and elasticity of youth.

to the improvement of the physical-and, through the If any are disposed to think that I have been carrying improvement of the physical, to the elevation af the this meeting into dream-land, let them pause and listen moral-condition of the human family. Unless, how. to the result of similar efforts to those I have been advo- ever, the history of the future of our race be wholly at cating, undertaken by a neighbouring country when on variance with the history of the past, the progress of the verge of ruin, and steadily pursued by the same mankind will be marked by alternate periods of activity country in the climax of its prosperity. “ The University and repose ; nor will it be the work of any one nation or of Berlin,” to use the words of Hofmann,“ like her sister of any one race. To the erection of the edifice of civilised of Bonn, is a creation of our century. It was founded in life, as it now exists, all the higher races of the world the year 1810, at a period when the pressure of foreign have contributed; and if the balance were accurately domination weighed almost insupportably on Prussia; struck, the claims of Asia for her portion of the work and it will ever remain significant of the direction of the would be immense, and those of Northern Africa not inGerman mind that the great men of that time should have significant. Steam-power has of late years produced hoped to develop, by high intellectual training, the forces greater changes than probably ever occurred before in so necessary for the regeneration of their country.” It is short a time. But the resources of Nature are not con. not for me, especially in this place, to dwell upon the fined to steam, nor to the combustion of coal. The steady great strides which Northern Germany has made of late water-wheel and the rapid turbine are more perfect mayears in some of the largest branches of industry, and chines than the stationary steam-engine; and glacier-fed particularly in those which give a free scope for the appli- rivers with natural reservoirs, if fully turned to account, cation of scientific skill. “Let us not suppose,” says would supply an unlimited and nearly constant source of M. Wurtz in his recent Report on the Artificial Dyes, power depending solely for its continuance upon solar " that the distance is so great between theory and its in- heat. But no immediate dislocation of industry is to be dustrial applications. This report would have been written feared, although the turbine is already at work on the in vain, if it had not brought clearly into view the im- Rhine and the Rhone. In the struggle to maintain their mense influence of pure science upon the progress of in- high position in science and its applications, the countrydustry. If unfortunately the sacred flame of science men of Newton and Watt will have no ground for alarm should burn dimly or be extinguished, the practical arts so long as they hold fast to their old traditions, and rewould soon fall into rapid decay. The outlay which is member that the greatest nations have fallen when they incurred by any country for the promotion of science and relaxed in those habits of intelligent and steady industry of high instruction will yield a certain return; and Ger- upon which all permanent success depends. many has not had long to wait for the ingathering of the fruits of her far-sighted policy. Thirty or forty years ago industry could scarcely be said to exist there; it is now At the conclusion of the Address the DUKE OF ARGYLL widely spread and successful.” As an illustration of the said I rise for the purpose of asking you to record a vote truth of these remarks I may refer to the newest of of earnest and hearty thanks to our distinguished President European industries, but one which in a short space of for the most able and instructive Address which he has time has obtained considerable magnitude. It appears just delivered. The President has modestly called a great (and I make the statement on the authority of M. Wurtz) | part of his Address a brief review of the recent triumphs that the artificial dyes produced last year in Germany of science. No one knows better than our distinguished exceeded in value those of all the rest of Europe, in- President the utter impossibility, within the short space cluding England and France. Yet Germany has no to which a presidential address is necessarily confined, of special advantage for this manufacture except the training giving an adequate idea of the immense activities of of her practical chemists. We are not, it is true, to at modern science. But those who look carefully over this tach undue importance to a single case ; but the rapid review, slight as the sketch may be held to be, will see growth of other and larger industries points in the same that it is a sketch drawn by a master hand. It gave us a direction, and will, I trust, secure some consideration for few points, but they are the salient points of recent discothe suggestions I have ventured to make.

very ; they were told in close connection with each other, The intimate relations which exist between abstract and above all they were told in that most valuable of all science and its applications to the uses of life have always conne&ions in relation to our duty as members of the

104 British Association.Mr. Perkin's Address. { I, ,

Sept. 8, 1876. British Association-in the connection between that which / educated mind. He knows as well as any man the has been already done and that which it still remains to things which private enterprise should be expected to do. There was one very remarkable passage of our undertake and what individual means cannot accomplish, President's Address—I do not know whether it has at- and therefore he at once assented to the sending out of tracted your attention as much as it attracted mine-in that great expedition, which, I believe, will be found to which he referred, lightly indeed, but significantly, to a have added immensely to our knowledge of the secrets of notion that there is at present a danger of decline in the nature. There is only one other observation in your scientific activities of England, and, he added, that the Address, Mr. President, to which I would direct the atperiods of great intellectual activity in the human mind tention of this meeting before I move the resolution of are almost always short. This may be true, and I am thanks, and it was that passage in which you spoke of inclined to think that if the remark is applied to literature there being no wall of partition between abstract and it is true, but my own impression is that as applied to applied sciences-do not let us ever quit hold of the science it is not true. We are at the present moment ground that the true spirit of science is to be found in the living in a golden age of scientific inquiry. As regards love of knowledge for its own sake. Applications are sure literature, it was only last week that I had the opportunity to follow applications infinitely greater in number and of conversing on the subject with a most distinguished amount than any human imagination could conceive man, who perhaps among many others was most able to beforehand; but we pursue science for its own sake, appreciate the matter of which he spoke, and he gave it thankful and grateful for the benefits to mankind which as his impression that as regards literature and philosophy it scatters around with so lavish a hand. And let me say, there was a marked decline in eminence and ability, and Mr. President, you might have added, let there be no certainly if we compare the state of literature now with wall of partition between science striály so-called and the burst of genius which illustrated the close of last speculative philosophy. I am sure you will be inclined century and the first twenty-five years of the present we to agree with me when I say that one of the dangers of may be inclined to come to that conclusion, for where is our modern science, arising from its very vitality and the galaxy that will compare with Burns, Scott, Words- spirit and energy and growth, is the tendency to let worth, Southey, and Campbell ? But when we come to speculation outrun knowledge. But the remedy for this science I rejoice to think that the contrast is remarkable is not to bar the way against abstract speculation of any indeed. Let me just remind this great assembly of the kind, not to forbid or ostracise it in our halls of science, names of the living, and the men who have lately left us. but rather to encourage it, and to remind scientific men, In geology we have names-the grave has only just closed to remind ourselves, and to remind the world that after over them- the names of Murchison and Sedgwick, of a all our discoveries how very little our knowledge is; and Lyell and Phillips; and I need hardly say that in those where science has discovered this she will recognise her we have a group of names in whose powerful hands a proper sphere, and philosophy will be chastened and subbranch of inquiry which but a few years ago was a ridicule dued. The noble Duke concluded by moving the thanks and a discredit has risen to be one of the most popular of the Association to their distinguished President for his and most certain sciences which illustrate the progress of admirable Address. the human mind. Then, again, physics. It is not very The motion was seconded by Sir WM. THOMSON, and long ago that we had Faraday, and I rejoice to say we was carried by acclamation. have still yourself, Mr. President. Again, in natural history we have Darwin and Walton, and even those who may not accept-and I am one of those who do not accept-the special theory of Mr. Darwin as a satisfactory

ADDRESS TO THE CHEMICAL SECTION explanation of the deepest mystery of nature,-namely, the history of creation. Even those who do not accept that theory must admit that Mr. Darwin stands A1

WILLIAM HENRY PERKIN, F.R.S., among the naturalists of the world. So, also, in com

President of the Section, parative anatomy. On this platform, in all these departments of science we have assembled to-night men whom I do not name because they are present, and because There can be no doubt that chemistry and the allied scithey are personal friends of many of us, but whose ences are now being recognised to a much greater extent names will be a household word in every home of science in this country than in former years; and not only so, the during generations which are yet unborn. Therefore, I workers at research, though still small in number, are repeat, we have no reason to fear any decline in intel. more numerous than they were. lectual activity so far as the discoveries and progress of In 1868 Dr. Frankland, in his Address to this Section at science are concerned ; and this brings me to another the Meeting at Norwich, commented upon the small observation of the President's, to which I confess I amount of original research then being carried on in the attach special value. I thank you for the wise and United Kingdom; but, judging from the statistics of the weighty words which you have spoken upon the vexed Chemical Society, this state of things became even worse, question of the endowment of research. ' I sometimes for in 1868 there were forty-eight papers read before the wonder if those who call for the endowment of research Society, but in 1872 only twenty-two. Since then, how. have ever thought what real scientific research is. You ever, there has been a considerable increase in the num. may pay and pension men for the mere collecting and as. ber; and at the Anniversary Meeting in March last it sorting of dry facts, but you cannot command by your was shown that the number of communications for the pensions or emoluments that fire of genius, that intuition Session had risen to sixty-six, or three times as many as of the mind, which is the secret of all true and real scien- in 1872. tific research. I should deeply deplore to see the day when or course these figures only refer to the Chemical scientific research was to depend for its appointments and Society, but I think they may be taken as a very safe crithe selection of its favourites upon any Minister or any terion of the improved state of things, though it would be Government. There is, indeed, another department of very gratifying to see much greater activity, the endowment of research in which I think it may take It is also very pleasing to find that the aids to and opa powerful and useful part, and I cannot illustrate that portunities for research are increasing, because it must be department better than by referring to the fitting out of remembered that, in a pecuniary sense, science is far from th" Challenger” Expedition. You all know that my hon. being its own rewarder at the time its truths are being fri:nd and former colleague, Mr. Robert Lowe, was con- studied, although the results very often become eventually sidered one of the hardest-fisted Chancellors of the of the greatest practical value; hence the wisdom of a Exchequer who ever filled the office, but he has a highly country encouraging scientific research.

BY

S,}

British Association.-Mr. Perkin's Address. Sept. 8, 1876.

105 But little, however, has been done in this direction in It was in 1825 that Faraday published, in the Philosopast years-the grants made for general science by this phical Transactions, his research on the oily products Association, and that of the Government of one thousand separated in compressing oil-gas, and described a subpounds annually to the Royal Society, being the most stance he obtained from it-a volatile colourless oil, which important.

he called Bicarburetted Hydrogen. Mitscherlich some The Chemical Society has also been in the habit of years afterwards obtained the same substance from bengiving small grants for the purpose of assisting those en- zoic acid, and gave it the name it bears. viz., “ Benzol.” gaged in chemical research. In the future, however, it This same chemist further obtained from benzol, nitrowill be able to do much more than hitherto. One of the benzol, by acting upon it with nitric acid. Zinin afteroriginal members of the Society, Dr. Longstaff, offered in wards studied the action of reducing agents upon nitrothe early part of the year to give one thousand pounds benzol, and obtained "aniline,” which he at that time provided a similar sum could be raised, the united amount called Benzidam. to be invested and the interest applied for the encourage- Again, Pelletier and Walter discovered the hydrocarbon ment of research. I am happy to say that rather more toluol in 1837. Deville produced its nitro.compound in than the required sum has been raised, and it is hoped 1841; and Hofmann and Muspratt obtained from this that it may be still further supplemented.

"toluidine," by the process used by Zinin to reduce nitroIn addition to the Royal Society grant, the Government benzol. have given this year a further annual sum of four thousand I might mention other names in connection with these pounds. Of course this is for science generally.

substances, such as Runge and Unverdorben ; but I would Mr. T. J. Phillips Jodrell has also placed at the disposal now ask, Did any of these chemists make these investiof the Royal Society the munificent sum of six thousand gations with the hope of gain ? was it not rather from the pounds, to be applied in any manner that they may con- love of research, and that alone ? and now these products, sider for the time being most conducive to the encourage which were then practically useless, are the basis of the ment of research in physical sciences.

aniline colours. But to go further : Doebereiner a long When we consider how much of our science is of a while ago obtained from alcohol a substance which he physical nature we must be grateful for this bequest; and called " light oxygen ether,” now known as aldehyd. it is to be hoped that these helps will more and more Gay-Lussac produced iodide of ethyl in 1815. Dumas stimulate research in the United Kingdom ; and if we and Peligot discovered the corresponding substance iodide have any hope of keeping pace with the large amount of of methyl in 1835 ; but, as in the cases I have previously work now being carried on in other countries, we must referred to, these bodies had no practical value, and were indeed be energetic.

never prepared but in the laboratory. Hofmann, in his The employment of well-trained chemists in chemical researches on the molecular constitution of the volatile works is now becoming much more general than hereto- organic bases, discovered in 1850 the replacement com. fore, especially on the Continent, where in some cases a pounds of aniline containing alcohol radicals. considerable staff is employed and provided with suitable All these compounds have now been manufactured on appliances, for the purpose not only of attending to and the large scale, and used in the futher development of the perfecting the ordinary operations which are in use, but industry of these artificial colouring-matters. to make investigations in relation to the class of manu. Other substances might be mentioned; but I think these fa&ure they are engaged in. A conviction of the necessity I are sufficient to show how the products of research which, of this is gaining strength in this country, though not so when first discovered and for a long period afterwards, quickly as might be desired; nevertheless these things were of only scientific interest, at last became of great are encouraging.

practical value; and it is evident that, had not the invesWith reference to the progress of chemistry and what tigations and discoveries I have referred to been made as have been the fruits of research of late years, it will be they were solely from a love of science, no aniline colours impossible for me to give even a general outline, the would now be known. a mount of work being so large; in fact, to recount the The colouring-matters I have hitherto spoken of are list of investigations made during the past year would nitrogenous, and derived from benzol and its homologues. take up most of the time at my disposal.

There are a few others, however, of the same origin Amongst the most interesting, perhaps, are those re- which contain no nitrogen; but they are of secondary lating to isomerism, especially in the aromatic series of importance. organic bodies; a:d it is probable that a more intimate I now pass on to another class of colouring-matter, knowledge of this subject will be found of really practical which is obtained from anthracen, a coal-tar product value.

differing from benzol and toluol in physical characters, As I am unable to give an account of the work done inasmuch as it is a magnificent crystalline solid. during the past year on account of its extent and diversity, The first colouring-matter derived from anthracen I propose to refer to some of the practical results which which I wish to draw your attention to, is alizarin, the have already accrued from Organic Chemistry, as a plea principal dyeing agent found in madder-root. This subfor the encouragement of research ; and those I intend to stance was for a long time supposed to be related to speak of are of special interest also on account of their close naphthalin, inasmuch as phthalic acid can be produced connection with the textile manufactures of Great Britain. from both of them; and many were the experiments made I need scarcely say I refer to the colouring-matters which by chemists in this direction; it was not, however, until have been obtained from the products found in tar. 1868 that this was proved to be a mistake, and its rela

It was in 1856, now twenty years since, that this in- tionship to anthracen was discovered by Graebe and dustry was commenced by the discovery of the "mauve Liebermann, who succeeded in preparing this coal-tar or "aniline purple ;” and it may be of interest to state product from the natural alizarin itself. that it was in Scotland, in the autumn of the same year, Having obtained this important result, they turned their that the first experiments upon the application of this attention further to the subject, hoping to find some prodye to the arts of dyeing and calico-printing were made, cess by which alizarin could be produced from anthraien; at Perth and Maryhill.

in this they were soon successful. I need scarcely remind you of the wonderful develop- The discovery of the artificial formation of alizarin was ment of this industry since then, seeing we now have of great interest, inasmuch as it was another of those from the same source colouring-matters capable of pro- instances which have of late years become so numerous, ducing not only all the colours of the rainbow, but their namely, the formation of a vegetable product artificially; combinations. I wish, however, to briefly refer to the but the process used by Graebe and Liebermann was of date and origin of the products which have served to build little practical value, because too expensive for pra&ical up this great industry.

purposes.

106 British Association --Mr. Perkin's Address. {CH WS,

Sept. 8, 1876. Having previously worked on anthracen derivatives, it If we want to introduce hydroxyl into a compound, occurred to me to make some experiments on this subject, there are several processes which can be used; but I will which resulted in the discovery of a process by which the only refer to those connected with the history of this colouring-matter could be economically produced on a colouring-matter. large scale. Messrs. Caro, Graebe, and Liebermann about The first process which I will refer to has been used by the same time obtained similar results in Germany; this chemists for a long period. It consists in first replacing was in 1869. Further investigation during that year the hydrogen by bromine, and then treating the resulting yielded me a new process, by which “ dichloranthracen body with potassic or other metallic hydrate ; and accordcould be used in place of the more costly product anthra- ing as one, two, or more atoms of hydrogen have been quinon, which was required by the original processes. I replaced by the bromine, so on its removal by the metal of mention this, as most of the artificial alizarin used in this the metallic hydrate, a compound containing a corres. country up to the end of 1873, and a good deal since, has ponding number of atoms of hydrogen replaced by been prepared by this new process.

hydroxyl is obtained. It was observed that when commercial artificial alizarin Graebe and Liebermann acted upon this principle in prepared from anthraquinon, but more especially from their experiments on the artificial formation of alizarin; dichloranthracen, was used for dyeing, the colours pro- and as it was necessary to replace two atoms of hydrogen duced differed from those dyed with madder or pure alizarin; in anthraquinon, they first of all prepared a dibrominated and many persons therefore concluded that the artificial derivative, called dibromanthraquinon, colouring-matter was not alizarin at all. This question,

C14H6Br202. however, was set at rest by separating out the pure artificial By decomposing this with potassic hydrate at a high alizarin from the commercial product and comparing it with temperature, they obtained a violet-coloured product, the natural alizarin, when it was found to produce exactly which, when acidified to remove the alkali, gave a yellow the same colours on mordanted fabrics, to have the same precipitate of alizarin, composition, to give the same reactions with reagents, and

C14H6(HO)202. to yield the same products on oxidation.

The second process I wish to speak of for the replaceBut whilst examining into this subject it was found that ment of hydrogen by hydroxyl in a compound is by cona second colouring-matter was present in the commercial verting it into a sulpho-acid (usually by means of sulphuric product, and in somewhat large quantities, especially acid) and subsequently decomposing this with potassic or when dichloranthracen had been employed in its prepara-other hydrate ; and, according as a mono- or disulphotion ; and to this was due the difference in shade of acid is employed, it yields on decomposition a compound colour referred to.

with one or two atoms of hydrogen replaced by hydroxyl. This substance, when investigated, was found to have The discovery of sulpho-acids of anthraquinon, and the same composition as “purpurin,” also a colouring- their use in place of the brominated derivative originally matter found in madder, but of very little value on account employed by Graebe and Liebermann, constituted the of the looseness and dulness of some of the colours it great improvement in the manufacture of alizarin already produces. This new substance, being derived from an- referred to. thracen, was named anthrapurpurin; unlike its isomer From what has just been stated, it was naturally suppurpurin, however, it is of great value as a colouring-posed that a disulpho-acid of anthraquinon would be rematter. I do not think I shall be going beyond the required to produce alizarin, and this was believed to be the sults of experience if I say it is of as great importance as case for some time; but further experiments have proved alizarin itself; with alumina mordants it produces reds of it to be a mistake, and shown that the mono-sulpho acid a more scarlet or fiery red than those from alizarin. In is required to produce alizarin, the disulpho-acid yielding fact, so fine are the colours produced that, with ordinary anthrapurpurin. alumina mordants on unoiled cotton, it gives results But how are we to explain this apparent anomaly ? It nearly equal in brilliancy to Turkey-red produced with would take up too much time to enter into a discussion madder or garancin; and I believe the rapid success of respecting the constitution of the sulpho-acids of anthra. artificial alizarin was greatly due to its presence. Most quinon in reference to the position of the HSO3 groups. of that consumed at first was for Turkey-red dyeing; and I will therefore confine my remarks to their decomposithe colours were so clear that it was mostly used in com- tion. bination with madder or garancin, to brighten up the Monosulphoanthraquinonic acid, colours produced by these natural products.

C14H (HSO3)O2, The purple colours anthrapurpurin produces with iron

when heated strongly with caustic alkali, as potassic or mordants are bluer in shade than those of alizarin, and the blacks are very intense. Its application is practically the

sodic hydrate, decomposes in the ordinary way, and we same as alizarin, so that they can be used in combina

get" monoxyanthraquinon,"tion.

C14H;(HO)O2, As already noticed, the commercial product called

which is a yellow body possessing no dyeing properties. “ artificial alizarin "first supplied to the consumer was

On further treating this, however, with caustic alkali it always a mixture of alizarin and anthrapurpurin ; and changes, being oxidised, and yields alizarin,various mixtures of these two colouring-matters are still

C14H6(HO)202 sent into the market; but, owing to the investigations that have been made and the study and attention that has

Disulphoanthraquinonic acid, been given to it by manufacturers, nearly pure alizarin

C14H6(HSO3)202, and anthrapurpurin are also sent into the market-the when subjected to the influence of caustic alkali, at first first being known as “blue-shade alizarin," and the changes into an intermediate acid, second as red or “ scarlet alizarin."

C14H6(HO)(HSO3)O2, The formation of anthrapurpurin in the manufacture of and then into a dioxyanthraquinon,alizarin may to some extent be said to have arisen from a want of knowledge of the true conditions required for the

C14H6(HO)202, production of the latter.

now known as “isoanthraflavic acid,”—a substance having It is now well known that alizarin is a dioxyanthra- | the same composition as alizarin, but being only an quinon, or, in other words, anthraquinon in which two | isomer of that body, and possessing no affinity for moratoms of hydrogen are repiaced by hydroxyl.

dants. Like monoxyanthraquinon, however, when further C14H802 C14H6(HO)202

heated with alkali it becomes oxidised, and yields a

colouring matter, which is “ anthrapurpurin," —
Anthraquinon.
Alizarin.

C14H5(HO)302.

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