acid. As yet this body has not been obtained in sufficient quantity and sufficiently pure for analysis; the fact that concentrated warm sulphuric acid does not char it, but only dissolves it, suggests some constitutional similarity to indigo. Tribrom-hydrocotarnine hydrobromide breaks up, on heating to 180-200°, in accordance with the reaction,

C12 H12 Br3 NO3, HBr=CH, Br+HBr+C1, H, Br NO,, HBr,

8

methyl bromide and hydrobromic acid being evolved and the hydrobromide of a new base being left. After due purification the free base is obtained from 80 per cent. alcohol in bright orange crystals containing C, H. Br NO„, 2H2O, the water of crystallization being lost at 100° and a brilliant crimson anhydrous base being left. This crimson mass is a delicate test for the presence of moisture in nearly absolute alcohol; when crystallized from such containing only a minute trace of moisture, orange hydrated crystals are thrown down on cooling, whilst crimson anhydrous crystals are formed when very carefully dehydrated alcohol is employed: it may be noted that long standing over and distillation from a large bulk of quicklime does not sufficiently dehydrate ordinary 90 per cent. spirit to give crimson crystals by this test.

The salts of this base readily crystallize; the hydrochloride and hydrobromide are of a straw-yellow colour and sparingly soluble in cold water; on adding sodium carbonate to the warm only slightly yellow aqueous solution, bright orange crystals of the free base separate rapidly on stirring.

The bromine in this base is apparently incapable of elimination by nascent hydrogen; it is proposed to designate it bromotarconine, "tarconine" (anagram of narcotine and of cotarnine) being the (as yet hypothetical) non-brominated base C1, H, NO,, differing from cotarnine (C12 H13 NO3) by the elements of marsh-gas.

12

On the Alkaloids of the Aconites. By C. R. ALDER WRIGHT, D.Sc. The results communicated to the Association last year, together with those obtained by Duquesnel, seem to point to the inference that when a mineral acid is used to acidify the alcohol used in the extraction of alkaloids from aconite roots, alteration of the base or bases originally present takes place to a greater or less extent, owing to the influence of the heat employed to evaporate the alcoholic extract; whereas if tartaric acid be used, and the extract be evaporated at as low a temperature as possible, as in the experiments of Duquesnel, much less alteration takes place and a considerable amount of a base crystallizable from ether is obtained. Two cwt. of Aconitum napellus were worked up by this latter process for the purpose of examining more closely the character of the crystals thus obtained; the extract, evaporated gently to a small bulk, was treated with water and filtered from precipitated resin; the aqueous filtrate then yielded a semicrystalline precipitate when treated with potassium carbonate in slight excess. This precipitate was fractionally crystallized from ether and other solvents, and finally split up into a large number of fractions; no evidence, however, could be obtained of the presence of more than one crystalline base; all the fractions, when sufficiently purified from a small quantity of an obstinately adherent non-crystalline base of lower molecular weight, gave identical numbers agreeing with the formula C3, H, NO12, the gold salt being indicated by C, H, NO12 HCI, AuCl ̧.

40

33 43

This crystallized base, to which it is proposed in future to restrict the term aconitine, is eminently active physiologically, and agrees closely in all its properties with the "crystallized aconitine" of Duquesnel obtained by the same process, the different formula arrived at by Duquesnel (viz. C, H, NO,,) being apparently due either to impurity in the substance examined or to analytical imperfections. The base, crystallizable from ether, obtained in small quantities from A. napellus by extraction with alcoholic hydrochloric acid, as described in the Brit. Assoc. Rep. 1875, p. 38, gave last year numbers from which the C3 H45 NO, or one closely similar, was deduced; after further purification, however, this substance was found to be perfectly identical with the aconitine above described, giving numbers represented by C, H, NO 12

33

33

In order to purify aconitine completely from another base which does not crystallize from ether, but which obstinately adheres to aconitine when crystallized from that and other menstrua, it is sufficient to dissolve the approximately pure snowwhite crystals already crystallized several times from ether in warm dilute hydrobromic acid; on cooling and standing, well-defined crystals of the hydrobromide of aconitine separate, the other base being completely retained in the mother liquors; the drained and washed crystals yield perfectly pure aconitine on dissolving in water, precipitating by sodium carbonate, and crystallizing the precipitate from ether. This non-crystalline base does not appear to form crystallizable salts; it has a considerably lower molecular weight than aconitine. Whether it is originally present in the roots, or is formed by alteration of the crystallizable aconitine during the extraction process, is not yet made out.

These results, and those obtained last year, clearly point to the desirability of substituting for medicinal purposes the uniform homogeneous crystallized base (or a salt thereof) for the more or less amorphous mixtures of aconitine and other substances and alteration products usually found in pharmacy, inasmuch as some at least of these admixtures are considerably less physiologically potent than aconitine, CH.NO.

Further experiments on the constitution of aconitine and the amorphous base or bases are in progress.

GEOLOGY.

Address by Professor J. YOUNG, M.D., F.G.S., President of the Section.

WHEN the British Association met in Glasgow twenty-one years ago, Sir Roderick Murchison presided over Section C, and was surrounded by a brilliant company, whose names, now historical, were even then familiar for their accuracy of observation, for philosophic generalization, and for the eloquence with which their science was clothed in words that charmed while they instructed-Lyell, Hugh Miller, Sedgwick, Jukes, Smith of Jordan Hill, Thomas Graham, Agassiz, Salter, Leonard Horner, John Phillips, Robert Chambers, H. D. Rogers, Charles Maclaren, Sir W. Logan the list is a heavy one even for twenty-one years; and the changed circumstances will be fully realized by Nicol, Harkness, Egerton, Darwin, Ramsay, and others when they find Murchison's place occupied by one who holds it rather by the courtesy of the Council to the Institution in which we are assembled than by any claim he has to the honour.

It would be out of place for me to do more than refer to the Geological advantages which have given to Glasgow its commercial greatness. In the Handbook prepared at the instance of the Local Committee will be found gathered together all the positive knowledge we possess regarding the mineralogy, stratigraphy, and palæontology of the west of Scotland. The specimens themselves are exhibited in the Hunterian Museum and in the Corporation Galleries; and I take it upon me to say the Glasgow geologists are as ready as ever to assist the investigations of students in special departments with all the material which richly fossiliferous strata yield and the careful skill of assiduous collectors can secure.

Thus relieved from entering into local details, I would ask your attention for a short while to some of the difficulties which a teacher experiences in summarizing the principles of Geology for his students.

I may be pardoned for reminding you that as yet there are in Scotland only two specially endowed teachers of Geology. In the Universities, that science for which Scotsmen had done so much received only the odd hours spared from Zoology. In 1867 the two courses were separated in Glasgow; in 1870 Sir R. I. Murchison founded the Chair of Geology in Edinburgh; in 1876 Mr. Honyman Gillespie endowed a Lectureship on Geology in Glasgow, not separating it from Zoology, but rather desiring the two to remain associated, while means were provided for tutorial instruction in the elementary work of the class. When next the Association meets

in Glasgow, I hope that the services which science has rendered to mining and metallurgy may have been recognized by those who have reaped the benefit. During the efforts of years to obtain provision for systematic teaching in Mining and Metallurgy, practical and scientific have always been set in opposition by those whom I addressed. In another twenty years it may have become apparent that it is possible for a man to be both practical and scientific, and that the combination is most conducive to economy.

Geology occupies the anomalous position of being a science without a special terminology, a position largely the result of its history, but to some extent inherent in its subject-matter. Treated of by Hutton and Playfair and their opponents in the ordinary language of conversation, current phrases were adopted into science, not so much acquiring special meanings as adding new ambiguities to those already existing. Every one seemed to understand them at once; and thus, as no one was obliged to attach very precise meanings to them, the instruments of research became its impediments, and the phrases in common use at the beginning of the century have transmitted to the present day the erroneous ideas of those by whom they were first employed. When Lyell, in 1832, methodized the knowledge accumulated prior to that date, he had, in organizing the science, to choose between inventing an appropriate terminology and adopting that in common use. By doing the latter he promoted the popularity of the science, though at the cost of some subsequent confusion; by attempting the former he would have set in arms against him those who would, according to the pedantry of the time, have denounced his neologisms and found in them a decorous veil for the objections which they entertained on other grounds to his views. Lyell was not the man to face the latter difficulty; nor can it be charged against him that he was wittingly neglectful of the interests of science. But to the use of conversational language are traceable certain assumptions to which I desire to draw your attention. In venturing criticism of this kind I am not unmindful of the Nemesis which has overtaken my colleague, Sir W. Thomson for his comments on Lyell's language. Thomson took exception to language which implied a kind of perpetual motion, a circulation of energy at variance with the teaching of physics; and, behold, two or three years after, Lockyer has published, as a physical astronomer, and Prestwich has approved, as a geologist, the opinion that the temperature of the sun may have fluctuated, that, in fact, changes of chemical combination may from time to time have refreshed the heat of the planet, whose uniform rate of cooling Sir William had assumed.

When stratigraphical geology first received due attention, the notion was prevalent that each formation terminated suddenly by cataclysm; it was therefore natural that the British succession, the earliest to be tabulated in detail, should be taken as a standard for other countries, and that the enumeration of the series should be a generalized section in which were incorporated those strata not present in Britain. The "intercalation" of beds thus practised to make an "incomplete" series "complete," still survives, as do the terms, though the notions which underlie them are formally denied by those who use them. A patriotic fellowcountryman once surprised us by his vehement denunciation of a treacherous Scot who called the Lanarkshire Limestones meagre and incomplete as compared with the English. With knowledge he might have made his criticism useful; as it was, he only gave a fresh example of the national peculiarity which, if it cannot prove Scotland to be better off than its neighbours, is content if it can make it out to be no worse. The abundant fossils of the Mesozoic strata of England and France rendered comparison easy, and created the impression that conchology was the ABC of geology, physical being subordinated to palaeontological evidence. The balance has been somewhat restored by the Geological Survey, the precision of whose physical observations enables them to guide the paleontologist as often as they have to be guided by him. But one legacy from our predecessors we have not got rid of; nor, indeed, has its value been much called in question.

The process of intercalation had at first to do only with observed gaps, into which obvious equivalents could be received. But as the needs of speculative Biology rapidly increased, in the same ratio did belief in the imperfection of the geological record increase, till now we have that record described as a most fragmentary volume, nay, as the remains of the last volume, whose predecessors are lost to us. 1876.

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Sir W. Thomson did good service by calling in question, on physical grounds, the indefinite extension backwards of geological time. The firstfruits of his crusade were the definitions of Uniformitarianism and Evolution which Prof. Huxley gave. Henceforth no one will maintain the onesided notions regarding these two opposing views of the earth's history which were adopted in ignorant misconception or dictated by conceit and bigotry. But the service done was even greater; for while it became clear that a knowledge of physics was indispensable to him who would promulgate sound notions, it was further apparent that both biological and geological evolution had a limit in time, that in fact, on the assumption of the primitive incandescence of our globe, the date might be at least approximately fixed when the mechanical processes now at work commenced and when the surface of the earth became habitable. Nothing more has yet been done than to point out the way; for, though Prof. Guthrie Tait indicates a limit of from 15 to 10 millions of years, that statement can only be regarded as in effect, though not perhaps in intention, a protest against the liberality and vagueness of Sir W. Thomson's allowance, which gave geologists a range of from one to two hundred millions of

years.

The reconciliation of physicists and geologists is not likely to come through Mr. Lockyer's researches, even if the earth's history be shown to have been identical, unless the renewal of the earth's heat be shown to be compatible with continued life on the surface. If the reconciliation is looked for through the prolonged duration of the sun's life, that being the gauge of the earth's duration, the expectation is still based on the supposed need of very great time for geological processes, or rather on the supposed need of very great time for biological evolution, to which geological evolution has been squared. There is another direction in which these results may help us to meet the limitation assigned by the physicists: the intervals of variation of temperature may be shorter than those which separate the maxima of eccentricity of the earth's orbit; and thus the repeated cold periods of which we have suggestions in the stratified rocks, may have recurred within a shorter total period than is at present claimed.

It is scarcely within the compass of this address to enter into the questions involved; but it is permissible to indicate the reason for delaying meanwhile acceptance of any precise limit of time. There is as yet too much diversity of opinion as to the elements of the problem. Physicists are by no means at one as to the conditions which permit or prohibit shifting of the earth's axis. Calculations are based on the assumption of the regularity of the earth's form, under a certain constant relation of the masses, albeit of diverse specific gravity, which compose it. It is moreover assumed that the ratio of land and water have been uniform, though the formation of the grand features of the land by contraction of the cooling mass has not yet been considered as affecting this assumption by altering the disposition of the water. On the one hand it has been shown that the existence of uniform temperatures over the earth's surface is a gratuitous hypothesis; on the other hand it is clear that the existing distribution of light and heat is incompatible with the flourishing of an abundant Carboniferous and Miocene flora within a short distance of the north pole. One expects that astronomers will look to the shifting of the axis of rotation as the possible explanation of the difficulty, taking into account likewise the shifting of the centre of gravity necessarily following those displacements of matter which, on the contraction theory, have determined the positions of the main continents and oceans.

Mr. Evans, in his address to the Geological Society, referred to the deviation of the magnetic axis as perhaps due to such shifting of the materials composing the inner mass of our globe. May not the conjectures of M. Elie de Beaumont be after all in the right direction? May not the change of trend which led him to classify the mountain-chains by reference to the age at which they had been elevated, be associated with movements which did not in all cases result in shiftings of the earth's axis so pronounced as those which permitted the Carboniferous and Miocene floras to invade successfully the arctic regions, or the phenomena of the glacial epoch, or epochs, to manifest themselves in the low latitudes where their traces have been recognized?

Waiving, for the present, inquiry into the influence which the admission of a

possible shifting of the earth's axis might have on our estimate of geological time, I shall return to the phraseology whose amendment seems advisable.

The confusion which exists is well illustrated in a remark by an eminent writer to the effect that the progress of geological research tends to prove the "continuity of geological time." The phrase in itself involves an absurdity; but what is meant is, that the successive so-called formations pass into each other by imperceptible gradation, and that, as time goes on, we shall be more and more able to intercalate strata so as to present a continuous scale of animal and vegetable forms. This is one out of many samples of the extreme length to which the thirst for strict correlation may go. We find in Murchison's writings and elsewhere pointed protests against the succession of strata in one district being held to rule that in other districts; but these are rather concessions wrung from their author by the pressure of particular instances than acknowledgments of a rule applicable to contiguous and to distinct localities alike. I could not perhaps take a better example than the strata which contain the remains of the fossil Equide. If we arrange the fossils in any series representing the modification of particular structures, or averaging the modifications of all the structures, we shall find that the terms of the series are met with, now in Europe, now in America; yet no one would venture to intercalate the European in the American Tertiary series so as to square the geological record with an assumed zoological standard. The notion of gradations, the extreme view of correlations, has led to results which are, to put it mildly, of doubtful value. Yet it was a natural result of the work of Cuvier and other paleontologists among the Mesozoic and Eocene fossiliferous deposits. The statistical method invented by Lyell is simply a mode of gradations. Intercalation of strata is therefore a survival from an earlier stage of the science, and carries with it a distinct echo of the catastrophic notion that strata were formed simultaneously and generally over the earth's surface, if not universally.

The geological record has been compared to a volume of which pages have here and there disappeared; and the incompleteness of the record has been inferred from the frequency of pronounced gaps in the succession of strata. Of these gaps, these unconformities, Prof. Ramsay has shown the importance by demonstrating that they represent the lapse of unknown, but varying, and in all cases considerable periods of time. The intercalation of strata, assumed to fill up the gap, and hereby to give symmetry to systematic classifications, can only be done by an appeal to the statistical method, a fauna containing forms characteristic of higher and lower beds being assumed to represent an intermediate point in time, whereas it might be equally well claimed as representing an intermediate area in space, and as being possibly representative of the whole gap and of some of the strata above and below it.

The definition of a formation as representing a certain period of time, still repeated with various modifications, is to blame for this and several other curiosities, of procedure. But the climax of symmetrical adjustments is reached when we find "natural groups" established-when, in other words, an attempt is made to show a regular periodicity of phenomena in Geology. Dawson proposed a quaternary, Hull a ternary classification-to neither of which should I now refer, but that the deserved estimation of these writers is apt to perpetuate what seems to be an unsafe view of geological succession.

Hull's arrangement has the merit, by force of its simplicity, of bringing the vainness of the attempt into prominence. Dawson has complicated his classification so as to render it impracticable. A natural group of strata, one in which elevation, deep depression, elevation, record themselves in rocks so as to establish geological cycles, implies several things for which we have no evidence. Most important of all, it implies that the events above noted should recur in every area in the same order, that they should recur at equal intervals of time, and therefore yield equal masses of strata, and, above all, that the superior and inferior limits of each natural and conterminous group should consist of a mass of similar strata, one portion of which shall belong to the earlier, the other to the later group. Here then we have implied, not catastrophic simplicity as regards the strata, but something very like it as regards the subterranean forces.

Mr. Hull has not, however, been able to surrender himself wholly to his specula