Chemical Science

British Association, 1883. Opening Address by J. H. Gladstone, Ph.D., F. R. S., V.I'. C. S., President of the Section. A sectional address usually consists either of a review of the work done in the particular science during the past year, or of an exposition of some branch of that science to which the speaker has given more especial attention. I propose to follow the latter of these practices, and shall ask the indulgence of my -brother chemists while I endeavor to place before them some thoughts on the subject of Elements. Though theoretical and practical chemistry are now intertwined, with manifest advantage to each, they appear to have been far apart in their origin. Practical chemistry arose from the arts of life, the knowledge empirically and laboriously acquired by the miner and metallurgist, the potter and the glass-worker, the cook and the perfumer. Theoretical chemistry derived its origin from cosmogony. In the childhood of the human race the question was eagerly put, “ By what process were all things made?” and some of the answers given started the doctrine of elements. The earliest documentary evidence of the idea is probably contained in the Shoo King, the most esteemed of the Chinese classics for its antiquity. It is an historical work, and comprises a document of still more venerable age, called “ The Great Plan, with its Nine Divisions,” which purports to have been given by heaven to the Great Yu, to teach him his royal duty and “the proper virtues of the various relations. “ Of course there ate wide differences of opinion as to its date, but we can scarcely be wrong in considering it as older than Solomon's writings. The First Division of the Great Plan relates to the Five Elements. “ The first is named Water; the second, Fire; the third, Wood; the fourth, Metal; the fifth, Earth. The nature of water is to soak and descend; of fire to blaze and ascend; o f wood, to be crooked and to be straight; of metal, to obey and to change; while the virtue of the earth is seen in seed-sowing and ingathering. That which soaks and descends becomes salt; that which blazes and ascends becomes bitter; that which is crooked and straight becomes sour; that which obeys and changes becomes acrid; and from seed-sowing and ingathering comes sweetness. “ * A similar i dea of five elements was also common among the Indian races, and is stated by Professor Rodwell to have been m existence before the fifteenth century B.C., but, (hough the number is the same, the elements themselves are not identical w!th those of the ancient Chinese classic; thus, II the Institutes of Menu, the “ subtle ether “ is spoken of as being the first created, from which, by transmutation spring, air, whence by the operation of a change, rises light or fire; from this comes water, and from water is deposited earth, These five are curiously correlated with the five senses, and it is very evident that they are not looked upon as five independent material existences, but as derived from one another. This philosophy was accepted alike bv Hindoos and Buddhists. It was largely extended over Asia, and found its way into Europe. It is best known to us in the writings of the Greeks. Among these people, however, the elements were reduced to four—fire, air, earth, and water—though Aristotle endeavored to restore the “ blue ether “ to its position as the most subtle and divine of them all. It is true that tbe fifth element, or “qumta essentia,” was frequently spoken of by the early chemists, though the idea attaching to it was somewhat changed, and the four elements continued to retain their place in popular apprehension, and still retain it even among many of the scholars who take degrees at our universities. The claim of wood to be considered ati element seems never to have been recognized in the West, unless, indeed, we are to seek this origin for the choice of the word LA.” to signify that original chaotic material out of which, according to Plato and his school, all things were created^ The idea also of a primal element, from which the others, and everything else, were originated, was common 11 Greece, the difficulty being to decide which of the four had the greatest claim to this honor. Tliales, as is well known, 11 the sixth century B.C., affirmed that water was the first principle of' things; but Anaxamenes afterward looked upon air, Heraclytus upon fire, and Theracleides on earth, as the primal element. This notion of elements, however, was essentially distinct from our own. It was always associated with the idea of the genesis of matter rather than with its ultimate analysis, and the idea of simple as contrasted with compound bodies probably never entered into the thoughts of the contending philosophers. The modern idea appears to have had a totally different origin, and we must again travel back to China. There, also II the s!xth century B.C., the great philosopher Lao-tse was meditating on the m\ steries of the world and the soul, and his disciples founded the religion of Taou. They were materialists; nevertheless, they belie ved 11 a “ finer essence, “ or spirit, that rises from matter, and may become a star; thus they held that the souls of the five elements, water, metal, fire, wood, and earth, arose and became the five planets. These speculations naturally led to a search after the subli mated essences of things, and the means by which this immortality might be secured. It seems that at the time of Tsin-she-hwang, the builder of the Great Wall, about two centuries before Christ, many romantic stories were current of immortal men inhabiting islands in the Pacific Ocean. It was 8upposed. that in these magi cal islands was found the ''herb of immortality v growing, and that it gave them exemption from the lot of common mortals. The emperor determined to go 11 search of these islands, but some untoward event always prevented him. t * Quoted from the translation by the Rev. Dr. Legge. In that most obscure classic, the “ Yi-King,” fire and water, wind and thunder, the ocean and the mountains, appear to be recognized as the elements. t Students of the Apocrypha will remember the expression in the Book of Wisdom, xi. 17, “r, TCavvoSvvapoi 6ov xetp nai nri6a6a ror no6por ££ apopcpov vA.,!?'' ("Thy Almighty hand, that made the world of matter without form “ . The same book contains two allusions to the ordinary element. vii. 17, and xix 18 to 20. The word 6roixelor is UBed in the New Testament only in a general seilse <2 Pet. lii. 10), or in Us more popular meaning of the first steps in kIWw- Nearly all the statements relating to this Taonist alchemy are derived from the writings of the Hev. Joseph Edkins of Pekin, and the matter is treated in greater detail in an article on the “Birth of Alchemy,” in the “ Argonaut,” vol. iii.; p. 1. 1 Some two or three centuries after this a Taouist, named Weipahyang, wrote a remarkable book called ' ' The Uniting Bond.” It contains a great deal about the changes of the heavenly bodies, and the mutual relation of heaven and men; and then the author proceeds to explain some transformations of silver and water. About elixir he tells us, “What is white when first obtained becomes red after manipulation on being formed into the elixir' ' (” tan” meaning red or elixir). “ That substance, an inch in diameter, consists of the black and the white, that is, water and metal combined. It is older than heaven and earth. It is most honorable and excellent. Arouud it, like a wall, are the sides of the caldron. It is closed up and sealed on every side, and carefully watched. The thoughts must be undisturbed, and the temper calm, and the hour of its perfection anxiously waited for. The false chemist passes through various operations in vain. He who is enlightened expels his evil passions, is delighted morning and night, forgets fame and wealth, comprehends the true objects of life, and gains supernatural powers. He cannot then be scorched by fire, nor drowned in water, etc. The caldron is round like the full moon, and the stove beneath is shaped like the half moon. The lead ore is symbolized by the White Tiger; and it, like metal among !he elements, belongs to the West. Mercury resembles the sun, and forms itself into sparkling globes; it is symbolized by the Blue Dragon belonging to the East, and it is assigned to the element wood. Gold is imperishable. Fire does not injure its luster. Like the sun and moon it is unaffected by time. Therefore the elixir is called ' the Golden Elixir.' Life can be lengthened by eating the herb called Huma; how much more by taking the elixir, which is the essence of gold, the most imperishable of all things! The influence of the elixir, when partaken of, will extend to the four limbs; tpe countenance will become joyful; white hair will be turned black; new teeth will grow in the place of old ones, and age at once become youth. . . . Lead ore and mercury are the bases of the process by which the elixir is prepared; they are the hinge upon which the principles of light and darkness revolve." This description suggests the idea that the elixir of the Taouists was the red sulphide of mercury—vermilion—for the preparation of which the Chinese are still famous. That Weipahyang believed in his own philosophy is testified by a writer named Ko-hung, who, about a century afterward, wrote the lives of celebrated Taouists, He tells how the philosopher, after preparing the elixir, took it, with his disciples, into a wood, and gave it first to his clog, then took it himself, and was followed by one of his pupils. They all three died, but, it appears, rose to life again, and to immortality. This brilliant example did not remain without imitators; indeed, two emperors of the Tang family are said to have died from partaking of the elixir. This circumstance diminished its popularity, and alchemy ceased tobe practiced in the Oelestial Empire. At the beginning of the seventh century the doctrine of Lao-tse was in great favor at the Chinese court; learning was encouraged, and there was much enterprise. At the same time the disciples of Mohammed carried their arms and his doctrines over a large portion of Asia, and even to the Flowery Land. Throughout the eighth century there were frequent embassies between eastern and western Asia, wars with the caliphs, and even a matrimonial alliance, We need not wonder, therefore, that the teachings of theTaouist alchemists penetrated westward to the Arabian philosophers. L was at this period that Yeber-Abou-Moussah-Djaferal- Sofe, commonly called Geber, a Sabman of great knowledge, started what to the West was a. new philosophy about the transmutation of metals, the Philosopher's Stone, and the Elixir of Life; and this teaching was couched in highly poetic language, mixed with astrology, and accompanied by religious directions and rites. He held that all metals were composed of mercury, sulphur, and arsenic, in various proportions, and that the noblest metal could be procured only by a very lengthy purification. It was in the salts of gold and silver that he looked for the universal medicine. Geber himself was an experimental philosopher, and the belief in transmutation led to the acquirement of a considerable amount of chemical knowledge among the alchemists of Arabia and Europe. This gradually brought about a conviction that the three reputed elementary bodies, mercury, sulphur, and salt, or acid, were not really the orginators of all things. There was a transition period, during which the notion was itself suffering a transmutation. The idea became gradually clearer that all material bodies were made up of certain constituents, which could not be decomposed any further, and which, therefor!', should be considered as elementary. The introduction of quantitative methods compelled the overthrow of medimval chemistry, and led to the placing of the conception of simple and compound bodies upon the foundation of scientific fact. Lavoisier, perhaps, deserves the greatest credit in this matter, while the labors of the other great chemists of the eighteenth and the beginning of the nineteenth centuries were in a great measure directed to the analysis of every conceivable material, whether. solid, liquid, or gaseous. These have resulted in the table of so- called elements, now nearly seventy in number, to which fresh additions are constantly being made. Of this ever growing list of elements not one has been resolved into simpler bodies for three-quarters of a century; and we, who are removed by two or three generations from the great builders of our science, are tempted to look upon these bodies as though they were really simple forms of matter, not only unresolved, but unresolvable. The notation we employ favors this view and stumps it upon our minds. Is it, however, a fact that these reputed elements are really simple bodies? or, indeed, are they widely different in the nature of their constitution from those bodies which we know to be chemical compounds? Thus, to take a particular instance, are fluorine, chlorine, bromine, and iodine es- senti ally distinct in their nature from the compound halogens, cyanogen, snlphocyanogen, ferricyanogen, etc.? Are the metals lithium, sodium, and potassium essentially distinct from such alkaline bases as ammonium. ethylamine, diethylamine, etc.? No philosophical chemist would probably venture to answer this question categorically with either “ yes” or “ no.” Let us endeavor to approach it from three different. points of attack-(l) the evidence of the spectroscope, (2) certain peculiarities of the atomic weighis; and (3) specific refraction. 1 . T.he Spectroscope.—It was at first hoped tlia t the spectroscope might throw much light upon the nature of elements, and might reveal a common constituent in two or more of them; thus, for instance, it was conceivable tbat the spectrum line of the bromine or iodine vapor might consist of the rays given by chlorine plus some others. All expectations of t h'lS have hitherto b een disappoi nted ; yet, on the other hand. it must not be supposed that such a re-suit disproves the compound nature of elements, for as investigation proceeds it becomes more and more clear that the spectrum of a compound is not made up of the spectra of its component parts. Again, the multiplicity of rays given out by some elements, when heated, in a gaseous condition, such as iron, has been supposed to indicate more complex constitution than in the case of those metals, such as magnesium, which give a more simple spectrum. Yet it is perfectly conceivable that this may be due to a complexity of arrangement of atoms all of the same kind. Again, we have changes of a spectrum at different temperatures; new rays appeal', others disappear; or even there occurs the very remarkable change from a fluted spectrum to one of sharp lines at irregular intervals, or to certain recurring groups of lines This, in all probability, does arise from some redistribution, but it may be a redistribution in a molecular .grouping of atoms of the same kind. and not a dissociation or rearrangement of dissimilar atoms. A stronger argument has been derived from the revelations of the spectroscope in regard to the. luminous atmospheres of the sun. There we can. watch the effect of heat enormously transcending that of our hottest furnaces, and of movements compared with which our hurricanes and whirlwinds are the gentlest of zephyrs. Mr. Lockyer, in studying the prismatic spectra of the luminous prominences or spots of the sun, has frequently observed that on certain days certain lines, say of the iron spectrum, are non-existent, and on other days certain other lines disappear, and that in almost endless variety; and he has also remarked that occasionally certain lines of the iron spectrum will be crooked or displaced, thus showing the vapor to be in very rapid motion, while others are straight, and therefore comparatively at rest. Now, as a gas cannot be both at rest and in motion at the same time and the same place, it seems very clear tbat the two sets of lines must originate in two distinct layers of atmosphere, one above the other, and Mr. Lockver's conclusion is that the iron molecule was dissociated by heat. and that its different constituents, on account of their different volatility, or some other cause, bad floated away from oDe another. This seems to me the easiest explanation of the phenomenon; and, as dissociation by heat is a very common occurrence, there is no a priori improbability about it. But we are not shut up to it, for the different layers of atmosphere are certainly at different temperatures, and most probably of different composition. If they are of different temperatures, the variations of the spectrum may only be an extreme case of what must be acknowledged by every one more or less—that bodies emit or cease to emit. different rays as their temperature increases, and notably when they pass from the liquid to the gaseous condition. And again, if the composition of the two layers of atmosphere be different, we have lately learnt how profoundly the admixture of a foreign substance will sometimes modify a luminous spectrum. 2. Peculiarities of Atomic Weights.—At the meeting of this Association at Ipswich, in 1851. M. Dumas showed that in several cases analogous elements form groups of three, the middle one of which has an atomic weight intermediate between those of the first and third, and that many of its physical and chemical properties are intermediate also. During the discussion uoon his paper, and subsequently,* attention was drawn to the fact tbat this is not confined to groups of three, but that there exist many series of analogous elements having atomic weights which differ by certain increments, and that these increments are in most cases multiples of 8. Thus we have lithium, 7; sodium, 23, i. e., 7 + 16; potassium, 39, i. e., 7 + (16 X 2); and the more recently discovered rubidium, 85, i. e., 7 + (16 X 5) nearly; and cresium, 133, i. e., 7 + (16 X 8) nearly. This is closely analogous to what we find in organic chemistry, wbere there are series of analogous bodies playing tbe part of metals, such as hydrogen, methyl, ethyl, etc., differing by an increment which has the atomic weight 14, and which we know to be CH2. Again, there are elements with atomic weights nearly the same or nearly multiples of one another, instances of wbich are to be found in tbe great platinum group and the great cerium group. t This suggests the luinlinrvof isomeric and polymeric bodies. There is also this; circumstance: the various members of such a group as either of those just mentioned sire found together at certain spots on the surface of the globe, and scarcely anywhere else. The chemist may be reminded of how in the dry distillation of some organic body he has obtained a mixture of polymerized hydrocarbons, and may perhaps be excused if he speculates whether in the process of formation of the platinum or the cerium group, however and whenever it took place, the different elements had been made from one another and imperfectly polymerized. But this*is not the largest generalization in regard to the peculiarities of these atomic weights. Newlands showed that by arranging the numbers m their order the octaves presented remarkable similarities, and, on tbe same principle, Mendeleff constructed his well known table. I may remind you that in this table the atomic weights are arranged in horizontal and vertical series, those m the verti- tal series differing from one another, as a rule, by the before mentioned multiples of 8—namely, 16, 16, 24, 24, 24, 24, 32, 32—the elements being generally analogous in their atomicity and in other chemical characters. Attached to the elements are figures, representing various physical properties, and these in the horizontal series appear as periodic functions of the atomic weights. The table is incomplete, especially in the lower portions, but, with all its imperfections and irregularities, there can be no doubt that it expresses a great truth of nature. Now, if we were to interpolate the compound bodies which act like elements—methyl, 15; ammonium, 18; cyanogen, 26—into Mendeleff's table, they would be utterly out of place, ' and would upset the order both of chemical analogy and of the periodicity of the physical properties. 3. Specific Refraction.—The specific refraction has been determined for a large majority of the elements, and is a very fundamental property, which belongs to them apparently in all their combinations, so long at least as the atomicity:j: is unchanged. If the figures representing this property be inserted into Mendeleff's* table, we find that in the vertical columns the figures almost invariably decrease as the atomic weights increase. If, however, we look along the horizontal columns, or better still, if we plot the figures in the table by which Lothair Meyer has shown graphically that the molecular volume is a periodic function of the atomic weights, • Phil. Mag., 1853. t Another curious instance is the occurrence of nickel and cobalt in all meteoric irons, with occasionalJy chromium of manganese, the atomic weights and other properties of which are very similar. t This exception includes not merely such changes as that from a ferrous to a ferric salt, but the different ways in which the carbon is com- Uned in such bodies as ethene, benzene, and pyrene. we shall see that they arrange themselves in a series of curves similar to but not at all coincident with his. The observations are not so complete or accurate as those of the molecular volumes, but they seem sufficient to establish the fact, while tbe points of the curves wonld appear to be, not the alkaline metals, as in Meyer's diagram, but hydrogen, phosphorus and sulphur, titanium and vanadium, selenium, antimony. Now, if we were to insert the specific refractions of cyanogen, ammonium, and methyl into this table, we should again show that it was an intrusion of strangers not in harmony with the family of elements. But there is another argument. to be derived from the action of light. The refraction equivalentof a compound body is tbe sum of the refraction equivalents of its compounds; and if tbcre i.s anything known for certain in the whole -inject, it is that the refraction equivalent of an organic compound advances by the same quantity (7'6) for every increment of CH. If, tberefore, the increment between the different members of a group of analogous elements, such as the alkaline metals, be of the same character, we may expect to find that there is a regular increase of the refraction equivalent for each addition of 16. But this is utterly at variance with fact; thus, in the instance above quoted, tbe refraction equivalent of lithium being 3'8, that of sodium is 4'8, of potassium 8'1, of rubidium 14 0, and of cresium about 18'7. Neitber does the law obtain in those series in which the increment is not a multiple of 8, as in the case of the halogens, where the increment of atomic weight is 45, and the refraction equivalents are chlorine 9 9, bromine 15'3, and iodine 24'5. The refraction equivalents of isomeric bodies are generally identical, and tlie refraction equivalents of polymeric bodies are II proportion to their atomic weights. Among Lliv- groups of analogous elements of the same, or nearly the same, atomic weight we do find certain analogies. Thus, cobalt and nickel are respectively 10'8 and 10 4, while iron and manganese are respectively 12'0 and 12 2. But, as far as observation has gone at present, we have conclude that, if metals stand to one ano her II the ratio of 2:1 II atomic weight, their refraction equivalents are mucb nearer together than that; while on the other hand, the equivalent vf sulphur, instead of beIIg the double of that of oxygen, is at least five times as great. The general tendency of these arguments is evidently to show that the elementary radicals are essentially different from the compound radicals, though their chemical functions are si milar. There remains still 1he hypothesi s that there is a “primordial element.' from which tlie otbers are derived by transmutation. With.the sages of Asia it was the “ blue ether,” witb Thales water, with Dr. Prout hydrogen. The earlier views -have passed away, and the claims of hydrogen are. being fought out on tbe battle field of atomic weights and their rigorous determination. There does not appear to be any argument which is fatal to the idea tbat two or more of our supposed elements may differ from one another ratber II form than II substance, or even that the whole seventy are only modifications of a prime element; but chemical analogies seem wanting. The closest analogy would be if we could prepare two allotropic conditions of some body, such as phosphorus or cyanogen, which should cary their allotropism into all their respective compounds, no compound of the one form being capable of change into a compound of the other. Our present knowledge of allotropism, and of variations in atomicity, affords little if any promise of this. The remarkable relations between the atomic weights of the elements, and many peculiarities of their grouping, force upon us the conviction that they are not .separate bodies created without reference to one another, but that tbey have been fashioned or built up from one another, according to some general plan. This plan we may hope gradually to understand better, but if we are ever to transform one of these supposed elements into another, or to split up one of them into two or three dissimilar forms of matter, it will probably be by the application of some method of analysis hitherto unknown. Notbing can be of greater promise than tbe discovery of new methods of research; hence I need make no apology to others who have lately done excellent work in chemistry if I single out the Bakeriati Lecture of this year, by Mr. Crookes, on “Radiant Matter Spectroscopy.'* It relates to the prismatic analysis, not of the light transmitted or absorbed in the ordinary way by a solid or liquid, nor of that given out by incandescent gas, but the analysis of the fluorescence that manifests itself in certain bodies when they are exposed to an electric discharge in a high ly exhausted vacuum. He describes in an interesting and even amusin£, manner his three years' quest after the origin of a certain citron band, which he observed in the spectrum of the fluorescence of many substances, till he was led into that wonderlul labyrinth of uncertain elements which are found together in samarskite, and eventually lie proved tbe appearance to be due to yttri um. As the test is an extremely delicate one, he has obtained evidence of the very general dissemination of that element, in very minute quantities—and not always very minute—for the polypes that built up a certain pink coral were evidently able to separate from the sea water, as their calcareous secretion contained about ^ per cent. of yttrium. We have reason to hope that this is only the first installment of discoveries to be made by this new method of research. I cannot conclude without a reference to the brightening prospects of technical chemistry II this country. I do not allude to the progress of any particular industry, but to the increased facilities for the education of those engaged in the chemical manufactures. First as to the workpeople. Hitherto the young artisan has had little opportunity of learning at school what wouk! be of the greatest service to him in his after career. The traditions of the Middle Ages were all in favor of literary culture for the upper classes, and the education suited for these has been retained in our schools for the sons of the people. It is true that some knowledge of common tbings has been given in the best schools, and the Education Department has lately encouraged the teaching of certain sciences in the upper standards. In the Mun- della Code, however, which came into operation last year, “elementary science” may receive a grant in all the classes of a boys' or girls' school, and in the suggested scheme there is mentioned simple lessons on “ the chemical and physical principles involved in one of the chief industries of England, among which agriculture may be reckoned,” while “Chemistry' ' is inserted among “ the specific subjects of instruction “ that may be given to tbe older children. It is impossible, as yet, to form an estimate of the extent to which managers and teachers have availed themselves of this permission, for the examinations of Her Majesty's inspectors under the new code have only just commenced; but one of the best of the Board Schools in London has just passed satisfactorily in chemistry, both with boys and girls. I trust that in those parts of tbe country where chemical industries prevail, cbembtry may be largely taken up in our elementary schools. The great deficiency fii our present educational arrangements is tbe want of the means of teaching a lad who has just left the common school the principles of that industry by which he is to earn his livelihood. Tbe more purely scientific chemistry, however, may be learnt by him now in those evening classes which may be formed under tbe Education Department, as well as in those that have long been established under the Science and Art Department. The large amount of attention that is now being given to the subject of technical education is creating in our manufacturing centers many technical classes and colleges for students of older growtb. As to inventors and the owners of our chemical factories, in addition to the Chemical Society and the Cbemical Institute, there has recently been founded the Society of Chemical Industry. It came into existence with much promise of success; at the close of its second year it numbered 1400 members; it has now powerful sections in London, Manchester, Liverpool, Newcastle, and Birmingham; and it diffuses information on technical subjects in a well-conducted monthly journal. May the abstract science and its useful applications ever prove helpful to one another, and become more and more one Chemistry for the benefit of mankind!

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