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142

Supersaturated Solutions.

CRÊMICAL NEWS,

April 4, 1879.

pose that for a moment. He battles stoutly against what every experiment. I naturally thought at first it was a he believes to be error, and I found no fault with that. case of scratching causing crystallisation ; but I had so What I did complain of was the passage which I quoted often scratched the acetate without effect that I was very in my letter of January roth. Every one to whom I have loth to believe it. I then washed the plate with boiling shown his paper agrees that the words as they stand dis water, and then scratching had no effect whatever on tinctly imply that I denied the fact of the lecture-table many drops of the same solution. The acetate has a experiment with Glauber's salt.

very remarkable power of adhesion, and was still present · Prof. Tomlinson denies that he anywhere implied this. in ihe depressions of the plate covered by weaker solution,

I am glad to accept this as an expression of his intention, but was unable to determine the crystallisation of the but I cannot admit it as a fair description of the words drops until scratching brought it in contact with the he used. I have laid stress on this only because the line strong solution. taken by Prof. Tomlinson in that paper is that I am at A few days ago I tcok an apparently clean plate, washed variance with all my predecessors, a point to which I shall it carefully in cold water, put drops of the acetate on it, have to recur, and that after repeating some of my experi. and then put it over calcium chloride. In an hour or two ments his results were contradictory of mine.

the modified salt was forming on the drops by evaporation; Prof. Tomlinson also protests against my making him then scratching with a pin made every drop crystallise. out to be ignorant of the very simple conditions necessary This looked very like a confirmation of Prof. Tomlinson's for the success of the experiments with drops on a glass results. But on washing the plate in hot water, and replate. The case stands thus :-In his paper he gives a peating the experiment, scratching had no effect whatever, general statement, applicable apparently to all supersatu. and when put back over sulphuric acid for two days only rated solutions, that when a point was drawn through a the modified salt was formed. Probably the plate had drop so as to deform it, crystallisation sets in. This is in previously been used for the acetate; possibly, in the first dry weather. I have drawn a point through hundreds of case, nuclei had not been thoroughly removed, but the drops of the strongest solutions of sodium sulphate, car. acetate is so little sensible of absorbents that this latter bonate, and acetate, on recently washed plates, in all supposition is not at all probable. kinds of weather, without causing crystallisation ; I have Again, a pin had been frequently used for making the just tried this with sixty drops of a strong solution of the acetate crystallise, and often heated red hot; it was acetate, and it was inactive in every case. I have de rubbed through the fingers and then left 31 hours in cold formed crops of ammonia alum, which had begun to water; it was then immediately active, not on quietly deposit the modified salt, on a plate over calcium chloride, I putting it into a drop, but on scratching; whilst boiling and repeated this with sodium carbonate and acetate over water cleaned it at once. sulphuric acid, and the scratching had no effect whatever It is evident that these facts must be taken into con. when the plates were put back over the chloride and acid. sideration if we do not wish to have results ascribed to

I explain this difference in our results by supposing that all sorts of wrong causes. Another fact of the same kind Prof. Tomlinson did not take sufficient care in cleaning is not without interest. Dr. De Coppet has described two his plates. There is nothing which need hurt him in the isomeric modifications of anhydrous sodium sulphate supposition, because it is only the experience given by a (Comptes Rendus, lxxviii., p. 194), one formed by dehydra. long series of experiments with plates which has taught iion above 33, the other formed at lower temperatures. me what precautions have to be taken. It is in the same This latter kind, he says, determines the crystallisation of spirit that Prof. Tomlinson quietly dismisses what he calls a solution of the salt as the normal, whilst the former my minute criticism, as throwing no light on the circum- does not. M. Gernez suggested that this was because at cumstances under which these solutions crystallise. Ex a luw temperature the sulpnate did not perfe&tly effloresce. perience has taught me that it is only by the minutest I tested the point by rubbing some of the salt very fine in possible criticism of each case that we can hope to arrive an agate mortar and then exposing it for weeks over cal. at the explanation of these very difficult phenomena. I cium chloride. I then took a plate with a large number recognise at present three well-established ways in which of drops of the su!phate and tested various portions by a supersaturated solution inay be made to give the normal taking up a little with a pin and introducing it into a salt. The first is by introducing a crystal of the same drop. I found that all the thicker parts were immediately salt, or of an isomorphous one of similar constitution as active, but that here and there a small very thin patch was Mr. Thomson has recently shown. The second is by the inactive, and the anhydrous could be seen to dissolve in mechanical action of absorbent substances, when not at he drop. Hence it is clear that M. Gernez's explanation once saturated by the solution. The third is by cold. is correct. This method of testing is one of extreme deliUntil it is proved that these three do not apply to the cacy for the presence of salts which form supersaturated case in point, I refuse to look for any other cause.

solutions. Now the first two of these causes exhibit the most ex. Another illustration of the necessity of minute investi. traordinary delicacy in their mode of operation. Mr. Igation is the following: Liversidge agrees with me in explaining the action of the Soine years ago I showed that scratching a solution of minute aërial nuclei by their absorptive power. Hence if sodium sulphate in about six parts of sulphuric acid Prof. Tomlinson's plates had minute organic particles on causes crystallisation. I attributed it at the time to them in dry weather these would cause the crystallisation vibration upsetting the state of unstable equilibrium. My of his drops when, by deforming them, he brought the colleague, Dr. Tilden, found that the same thing happened solution in contact with these nuclei. He notices himself when drops of potash alum were scratched; and at a that if the tail formed sprang back crystallisation did not lecture in Bristol lie gave it as another instance of vibra. ensue, and I have always found that plates exposed to air tion. But I have since found that by taking extreme care are much more likely to be active ihan plaies recently in cleaning the plate and using one recently washed washed or dried under cover.

scratching is by no means always active. I attribute this The extraordinary delicacy of the second cause has case also to the presence of absorbents on the plate. I been proved in the course of my own experiments, of, am also strongly inclined to believe that the effect of which I will give a few. A large glass plate, on which scratching the acid solution mentioned above is due to drops of sodium acetate had been made to crystallise, was the same cause. Rubbing drops of this with a hard, com. carefully washed in cold water, and then dried and exposed pact wood has no effect, but it always crystallises by to the air. A great many drops of a strong solution of absorption on the end of a match simply dipped in the the acetate were then put on it, and all remained liquid ; / drop and laid aside. Little shavings of a match kept but I found that scratching with a pin inside the drops floating on a drop act in the same way, but very often not made every one of them crystallise instantly, although the lif they are pushed into the drops. It is easy to see how in was washed in boiling water or heated red-hot after the solution would gradually act on the organic particles News

in the depressions of the plate, and then scratching brings the conditions under which the crystals were formed is, the crystals which are forming into contact with the interesting to geolcgists as well as chemists. stronger solution, I did once find a plate inactive when The last point I have to notice is one which Prof scratched, but I have never been able to reproduce the | Tomlinson insists upon in his paper, and in his note to conditions, although I have tried several ways of cleaning | you ; it is that I am at variance with all my predecessors. the plates. It must also be carefully borne in mind with He says that Loewel, Violette, and Liversidge expressly regard to these experiments with drops that the sensitive state that porous bodies, bodies greedy of water and ness to absorbents depends on the strength of the solu- capable of hydration, are incapable of determining the tion, and also on the temperature.

solidification of these solutions. In hot weather I found that a rather weak supersatu. He has forgotten, as I did at the time of making my. rated solution of sodium sulphate was absorbed by filter. experiments on absorption, that Mr. Liversidge, in his paper without giving the normal salt even when dry, as last paper in August, 1870, enunciated the absorption the filter-paper was cut up and introduced into drops with theory in these words:out producing any effect. This can never be done, as far “(1) It is not impossible that nuclei consist of microas my own experiments go, with strong solutions of that scopic organisms which act by abstracting water, the salt. Absorbents also, such as filter-paper, have no effect action being set up at a point from which it is propagated whatever on sodium acetate except in the very strongest throughout the mass ; (2) that they are rendered inactive solutions.

by heat because it entirely destroys them ; (3) that their It appears, then, that in discussing the question why action is arrested by previous saturation in water, because these solutions crystallise or do not crystallise in a given | they then can no longer abstract water from a saline case, we have to take account of the strength of the solu- solution." tion, or the temperature, of the possible presence of the He had only made a couple of experiments with lyco. salt when least expected, of the freedom of the plate from podium, which he found to be active when dry and in. dry absorbent bodies derived from the air or elsewhere, | active when wet, but he expressed a hope to have and of a specific sensitiveness to absorbents peculiar to shor:ly the results of other experiments. Unfortunately, : such kind of salt. This necessitates minute criticism, he never resunied the subject. My own experiments on and with all deference to Prof. Tomlinson's opinion, I absorption were begun five years later, when I had formaintain that one or other of these considerations has gotten all about Mr. Liversidge's suggestion, and when I frequently led me to a simple explanation of results which was working at a different part of the subject. They enare otherwise most puzzling. The action of oil on these tirely confirm Mr. Liversidge's views as to the action of solutions is a very simple one according to Prof. Tom- nuclei; they show that the action of absorbents in con. linson; when a film adheres to the solution the normal siderable quantity resembles that of nuclei, but with two salt separates. But I find that the phenomena are much important modifications, which determine the conditions more complicated.

under which the absorbents act-namely, that they are When solution of sodium carbonate is dropped into oil, inactive if saturated at once by the solution, and that very or is rubbed with oil, a salt separates at once, which is not rapid absorption often prevents crystallisation. It is only the normal salt, as it can be introduced into drops without in virtue of this extension and modification that I can causing crystallisation. I have also seen a very pretty lay any claim to the theory as my own, and my results are thin flexible opalescent film form at once round the sides in perfect harmony with those of the only person who, of a drop of ammonia alum on oil. As I write, three with the exception of Prof. Tomlinson and M. Gernez, drops of a strong solution of potash alum are lying un- has really worked at this subject in recent years. It is altered in castor oil; yet I have often found oil rubbed true that Loewel, Violette, and Liversidge state that phos. on a plate powerfully unclear to this solution. On sodium phoric anhydride and other dehydrating substances have acetate I have never found oil have any effect, nor on the no effect ; but I have shown that when these substances sulphate when proper precautions are taken. It is quite are introduced into a considerable bulk of the solution, so possible that the oil acts by catching up absorbent par as to be saturated at once, crystallisation does not ensue. ticles of dust, but the subject needs investigation.

I have omitted to notice a property possessed by these solutions which may easily prove a source of error. When small well-shaped crystals of the salt are sorming in a

ON INDIGO-BLUE solution or in a drop ihey may continue to grow for hours

FROM very slowly; but if one of these is broken the drop crystallises with a flash. It may, as far as my experiments POLYGONUM TINCTORIUM AND OTHER go, be taken as a general law that broken crystals have

PLANTS. much more effect in producing crystallisation than perfeatly-shaped ones. The crystal seems to have the

By EDWARD SCHUNCK, Ph.D., F.R.S. power of growing with much greater rapidity along one

(Concluded from p. 130). of its axes than along the others. It is this property which makes a strong solution crystallise in fibres, while a weak solution gives well-shaped crystals. In the former

Bletia Tankervillia, case the growth of the more powerful axis does not suffi- THE occurrence of a blue colouring.matter in this and ciently diminish the strength of the solution in front of it other plants belonging to the Orchidaceæ, such as Calanthe to check the rate of growth; in the latter case the crystal |

veratrifolia, was first noticed by Clamor-Marquart and is surrounded constantly by impoverished solution, which

by the late Dr. Crace Calvertt. The attention of these gives time to the lateral forces to develop themselves.

observers was directed to these plants by seeing the blue Hence a drop on a plate may really be crystallising in

colouration appearing in the white petals of the flowers thedepressions of the plate, but very slowly, and the ex

on their beginning to fade; and they found the blue perimenter will find that scratching causes crystallisation

colour to be due to indigo. In accordance with the views at once, or that the drop will crystallise spontaneously

then prevailing, they assumed the pre-existence of the after a certain time.

colouring-matter, either as indigo-blue or as its hydride, in I find that a pin which has been heated red-hot often,

the tissues of these plants. It is easy to see, however, and is used for making the acetate crystallise, and is then on reading the accounts of their experiments that the Jeft in water for an hour or two, makes drops of the ace- colouring-matter was really formed during the processes tate crystallise very slowiy in large well.formed crystals, whilst scratching makes it crystallise at once in fibres all

* Buchner, Repertorium f. die Pharmacie, B. lvii. S. i. over. This subject of the relation of crystalline form to

+ Journal de Pharmacie, t. vi , p. 193.

144
Indigo-Blue.

SCABNICAL NEWS,

1 April 4, 1897 employed for its extraction; and it seemed to me, therefore, i

Polygonum Fagupyrum (Buckwheat). highly probable that the plant would be found to contain

Polygonum Persicaria. some glucoside similar to indican.

Rhinanthus Crista.galli. Bletia Tankervilliæ is not difficult to procure, being fre.

Sophora japonica. quently grown for the sake of its handsome brown and

Spilanthes oleracea. white flowers and its general beauty. The leaves of the

The leaves of these plants, when treated in the manner plant having been cut in pieces and ground with water

above described, yielded no trace of any substance resem. between two stones to a pulp, which is strained through

bling indican, and showed no indications of containing any calico, yield a green muddy liquid which, heated to near

| blue colouring.matter like indigo. the boiling-point, gives a thick green coagulum. The liquid filtered from this coagulum is clear, of a deep yellow colour, with a slight acid reaction and an acrid taste. When this liquid is mixed with sulphuric or hydrochloric CRYSTALLISATION OF PHOSPHORUS. acid and lefi to stand, it deposits dark-coloured flocks

By GEORGE WHEWELL, F.I.C., F.C.S. consisting of indigo-blue mixed with a substance which imparts a purple colour to boiling alcohol, probable indi. rubine. The presence of glucose may be detected in the IN 1872, while experimenting on the action of phosphorus filtrate by the usual test, while the same test applied i on nitrogen gas in sealed tubes, alter melting the phosbefore the addition of acid shows no indication of its phorus and spreading it over the sides of the tube and presence. It may hence be inferred that the liquid con allowing the tube to stand for several weeks, I noticed iains in solution a glucoside similar to, if not identical small colourless crystals begin to form. In 1874 I noticed with, indican. It undergoes, like indican, a complete abstracts of two papers in the Chemical Society's journal change when submitted to the action of alkalies; for if its (2nd series, vol. xii., p. 869) by J. L. Smuih and W. L. walery solution be mixed with caustic alkali and boiled, Herman, on the formation of crystals of phosphorus in then with an excess of sulphuric acid and again boiled, it vacuo. I wrote a note to the Chemical News (vol. XXX., deposits brown flakes, which are found to contain but p. 168). I did not claim priority or originality, or try in little indigo-blue, while in the filtrate only a trace of any way to detract from the merit of Messrs. Smith and glucose can be detected. The same change takes place Herman's papers. In Mr. Herman's letter (vol. XXX., gradually when the watery solution is left to stand for p. 194) he tried to throw ridicule on my note, and even several days at the ordinary temperature.

hinted his opinion that I had not made any crystals at · The gradual formation of indigo-blue in the leaves of all. I prepared a test-tube and sent it to Dr. Burghardt, Bletia Tankervilliæ may be easily traced in the same of the Owens College, Manchester, and I append his way as with those of Polygonum tinctorium, by placing the | letter, as requested by Mr. G. E. Davis (vol. xxxix., p. 115). lower ends, immediately after cutting, in dilute hydro

“The Owens College, Manchester, chloric acid and leaving them freely exposed for a few

"March 2, 1875. days. The acid, as it ascends, causes a dark discoloura.

“Dear Sir, tion ; and the part discoloured, aiter immersion in boiling "... I thoroughly investigated the matter you realcohol to remove the chlorophyll, appears blue.

quested me to enquire into, immediately alter receiving

the tube containing the phosphorus crystals. Of course Indigofera tinctoria.

you are aware that crystals of phosphorus have been ob• It would be a matter of some interest to ascertain in tained in other ways long ago, and it was conclusively what state the colouring.matter exists in this the most proved that they belonged to the regular system of crys. important of all the plants yielding indigo. From what I tallography. The crystals in the test-tube you kindly sent have said, however, it will be apparent that, in order to me were undoubted phosphorus crystals, exhibiting the arrive at a certain conclusion, it would be necessary to

two characteristic forms observed on crystals prepared by work with fresh leaves; for if they contain a glucoside re. dissolving phosphorus in rock-oil when hot and cooling, sembling indican, this would in a very short time undergo and the methods published long ago. The forms I obcomplete decomposition. I obtained some seeds of Indi. served were the regular octahedron and the rbombic dodeca. gofera rinctoria from Messrs. Vilmorin, Andrieaux, and Co., hedron, with rather rounded edges, the interfacial angles and treated them in accordance with the directions they not being sufficiently well defined to allow of accurate kindly gave me. The seeds germinated, and the young measure ments being made. There can, however, be ao plants lived for some time in a hothouse ; but unfortu. doubt abuut their being the two forms mentioned above. nately, they attained no great size, and soon decayed and On opening the tube for a few seconds sumes of phos. died, so that I was unable to obtain a quantity of leaves phorus came out, and the tube on being closed again, and sufficient for examination.

| left alone for a few days, was thickly coated with amor. Mr. P. Michéa, an intelligent indigo-planter, with whom phous phosphorus and the crystals had vanished.... I have been in correspondence, gives me, however, some

ce, gives me, however, some Believe me, &c., interesting information relating to this part of the subject.

"C. H. BURGHARDT." Mr. Michéa writes to me as follows:-" It was my finding

“The Owens College, Manchester, in the Indigofere of India in the wild plant which grows

“March 18, 1879. at many places in the three Presidencies as well as in the

“Dear Sir, cultivated species of Bengal, the North West, and Madras)

L "... The forms observed on the crystals were the a glucoside substance perfectly similar to the indican of octohedron and the rhombic dodecahedron, the former the Isatis tinctoria in all its properties, which made me predominating; the crystals did not exbibit any sharply. declare that the colouring-matter of the Indian Indigoferæ defined edges or angles, consequently goniometrical mea. was due to indican."

surements were not possible. The crystals were perfealy The experiments just descrihed lead to the conclusion transparent. ...-With kind regards, &c., that in all the indigo-yielding plants hitherto examined,

“ C. H. BURGHARDT." the colouring-matter is derived from a glucoside which My friend, Mr. W. H. Wood, now of the Yorkshire splits up with great ease into indigo-blue and glucose, and

College, wrote me, in November, 1874:that this glucoside is probably, in all cases, the same, and . I have tried your method of producing phosphorus identical with, the indican ot Isatis tinctoria.

crystals and was successful, as I could easily distinguish · Various other plants have been supposed to yield indigo crystals when I examined the tube two or three days blue. Of these I have examined the following:

after. ..." Galega officinalis.

. Very few chemists have made crystals of phosphorus, Hedysarum Onobrychis (Sainloin).

| and the only thing I claim in the above method is a very

News

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ready means of preparing crystals of phosphorus suitable, In every kind of spectroscopic observation, high or low, for lectures or showing it to a class when treating of phos- of fire or flame, public or private, brilliantness in the light phorus and its compounds. The method places phosphorus operated on-so far as it can be fairly commanded-is the crystals in the hands of anyone who cares to spend ten or soul of success. In private researches, too, more particu. fifteen minutes in preparing them. I am sorry I have not larly, where we merely look into the eye-piece of a small studied the subject further, being fresh from College at optic tube for our own sole and, for the time, solitary the time, and the note being my first attempt at writing I satistadion, the mere quantity of shining matter being was somewhat cowed. I came to the conclusion that Mr. examined is of no sort of consequence ; for we view of it Herman thought he had a vested right in crystals of at a time only as much as fills a little slit in a metal plate phosphorus.

about g'o inch high and to inch broad. A minute, or no I have found the following the best plan for producing | more than microscopic sized, particle is therefore cnough, the crystals :- Take a piece of glass tubing and seal one in that way; but brilliant, and even three t mes brilliant, end (or a test-tube); place at the bottom of the tube a the intrinsic light of that little particle must be, or you piece of phosphorus about the size of two peas; draw out will be condemned to employ only the least dispersive of the other end ; then heat the tube, commencing about one prisms wherewith to form its spectrum ; and therein, inch or so above the phosphorus, so as to drive out as from the extreme red, all the way through the orange, much air as possible; then seal the open end (or cork the yellow, green, blue, and right up to the ultimate violet test-tube and make it air-tight). Melt the phosphorus, and land lavender grey of the spectral field, you will fail (if spread it as thinly and evenly over the sides of the tube your spectrum is of the all important discontinuous" as possible. Allow to stand for a week or two, or place order) to see anything but inerely a few faint, hazy-edged, into a freczing mixture, when crystals will form in a few unsatisfactory bands. In place it might, or should, have days.

been of multitudes of vivid lines, capable of almost un. limited nicety of micrometric measurement, and as firmly

fixed in their several and respective spectrum places, END-ON ILLUMINATION IN PRIVATE

as are the very stars of heaven in their almost eternal

positions. SPECTROSCOPY,

" Then, of course," you will say, “every sensible AND ITS

spectroscopist, whenever at least he is observing in a APPLICATIONS TO BOTH BLOWPIPE FLAMES

chamber upon any chemical element within his grasp, AND ELECTRIC ILLUMINED

endeavours to make the illumination, or incandescence

under which he looks at that particular matter, as bright GAS-VACUUM TUBES.*

as he possibly can." By PIAZZI SMYTH,

Most certainly! That is exactly what he does, and even Astronomer Royal for Scotland, and past President of R.S.S. Arte.

glories in doing ; for he finds that he cannot make the

said stuff too bright for the spectroscope, if only he prePart I.

serves it at the same temperature. But precisely there Defects of Former Methods, and New Conditions to be

comes in our envious and opposing lion; for almost every Fulfilled.

known attempt of man as yet to increase the brightness

of a light, when at all successful in that respect, is found As there is nothing in the shape of splendid optical pro in the end to have enhanced its temperature amazingly. jedion of grand phenomena on a large screen connected And if the .emperature be so enhanced, where is the man with the present paper, and as it refers merely to a prac

who shall venture to predia, from theory alone, what the tical difficulty, as met with by a private worker in a small

result will be in that potentially, most extensive, almost way, in connection, too, with only a very limited branch

interminably long region of accurately measurable facts, of the general subject of spearoscopy,--some apology may the prismatic spectrum of light ; wherein red is from, be necessary for bringing so apparently trilling a matter

violet, as far as north is from south ? before any public meeting. Especially, too, is such an

Do you doubt there can arise any real and serious explanation required before this long-established Society, |

Society, spectral changes from merely altering the temperature of which has had all the finer bearings of the higher spe&rum

one and the same flame of burning matter? Look at the analysis expounded to its members so often and so

metal lithium in any of its salts. How early in the eloquently by Dr. Stevenson Macadam, and illustrated so

history of spectroscopy did not that too little appreciated glowingly by Mr. Hart's electric lamp, years and years ago, genius Fox Talbot show that chloride of lithium in a that not a few persons may have almost identified the

lamp flame formed one brilliant line in the scarlet-red and subje& itself, or anything about spectroscopy, with that

another very faint one in the orange-brown of the spectrum. particular and assuredly most magnificent method of

Wherefore the brighter of them was called lithium a, the demonstration. My excuse, therefore, can only consist

paler lithium ß; and the innocent, trusting public thought in trying to make out, and perchance bringing home,

they would always know where, in the spe&rum, by those though by more words only, to the inner conscience of

letters as names, to find those lines. some real workers (of whom there must be many here)

But after the subsequent grand outcome of the full the exact manner of occurrence of a serious, albeit small, l spectrum analysis of Professors Bunsen and Kirchoff, and case of positive scientific difficulty; or in showing how a

ing how a when not a few men insisted on rising from the mere

wher very lion of a trouble was one day found to be seated

to be seated beginnings of heating by flame, up to the ecstatic increase

beginnin right across the special path of progress and research of temperature by the electric spark,-behold the lithium's which I was desirous of pursuing. But how, after due i red line, though still in exactly the same part of the interrogation as to wherefore he came to be there, the said

nere: the said | spectrum's measured scale as before, has become woefully lion was presently induced to get up, make himself scarce,

pale; the lithium orange line has burned up like a beacon; and not exhibit his threatening front, to me at least, in

and far, far away in the comparatively distant regions of tbat locality again.

the spectral blue, there is a new line of almost rivalling If, therelore, the Society will be graciously content with

brightness. Wherefore a new naming of the lines by such a modest bill of quiet fare as that, I will at all events !

Greek letters takes place among spark observers; the endeavour to make the nature of the case very clear. identical lithium B of flame-spectroscopy becoming lithium With this purpose, therefore, I now commence with what

nata of electric spark spearoscopy; a line hitherto unknown

of eledric spark spearosc is generally admitted by all the world as being founda

becoming lithium y; and poor old lithium a being known tional in spe&roscopy; while it is also the necessary now only as lithium B. beginning of our subjca for this evening, viz. :

But even that is not the end of the changes of bright. * Read before the Royal Scottish Society of Arts, February 10, 1879. I ness and name with incrci i of temperature ; for pres.

CHEMICAL News, 146 Chemical Society.-Anniversary Meeting.

April 4, 1879. ently still more ambitious geniuses increase the power of , much ground for congratulation, the past year having their galvanic batteries, the size of their induction coils, been one of quiet prosperity. Various alterations have the length of their sparks, and then condense them both been made in the bye-laws, and the publication of the in time and space with Leyden-jar apparatus until the Society's Journal has been improved.' 61 Fellows have heat is something so fearful that, in the spectrum of one been elected, and 18 have died, withdrawn, &c., during the and the same:lithium salt, it is no longer the red, nor the past year, the present number of Fellows being 981. There orange, nor even the blue line you care for now; but are 34 Foreign Members and i Associate ; 28 names are further away in more distant spectral regions there burns awaiting election. The Treasurer's report shows an ina violet line; and beyond, yes, vast!y further beyond that crease of receipts over expenditure to the amount of still, there arise exquisite lines in the ultra lavender and £1964 gs. 5d. (including a legacy of £100o from the late ever grey wilds of spectral space. So then, to suit these Mr. Sidney Ellis). 68 papers have been read before the altered brightnesses in the hotter condensed-spark spec. Society during the pasi year. Lectures have been given trum, a new and yet more altered application of Greek by H. C. Sorby and S. H. Vines. The number of papers letters, as names, takes place; and being attended to in from 1859 to 1869 averaged 36 annually, sell as low as 22 their Memoirs by some persons, though not by others, in 1872, and since has rapidly increased. There is an inwill contribute to the future scientific confusion of many; creasing disposition to illustrate papers by experiments: this and all on account of a mere change of temperature in a practice adds much to the interest of the meetings of the lithium light.

I Society. On the 13th of November last Prof. Würtz Or hear those first-class German observers MM. Plucker| delivered the Faraday Lecture at the Royal Institution, and Hittorf, at page 6 of the Philosophical Transactions Sur la Constitution de la Matière à l'etat Gazeux." for 1865, as to what still more extensive and positively Those who were present will not readily forget the perfect wholesale and radical spectral changes, mere altered lucidity, the rare manipulative skill, or the enthusiasm of degrees of heat may work. “The first fact,” say they, the Lecturer on that occasion. The Council have care“which we discovered in o, era:ing with our tubes, guided fully considered the condition of the Library and its rules. by the above-explained principles, was the following It has been resolved that no serial publication of which one :- There is a certain number of elementary substances the Society does not possess a duplicate copy shall be which, wlien differently heated, furnish two kinds of taken away from the rooms. Duplicate copies of back spe&tra of quite a different character, not having any line numbers of Liebig's Annalen and the Annales de Chimie or band in common.” So that if you have learned to et de Physique have been ordered, and these works, recognise every line in the spectrum of. say, nitrogen at together with other important serial publications, are now one temperature, it will not be by ary of those lines, 1 being taken in in duplicate. Many new books have also but by some perfectly different and unlikely-looking ones. I been ordered, and on this roint the Council would be glad that the element will manisest, or for a while conceal, of suggestions from Fellows of the Society. Arrangeitself at another temperature !

ments have been made for Fellows at a distance to have Neither does the application of a higher leat always books sent to them on giving a writeen order and paying brighten and improve a spectrum, as witness the element the cost of carriage. A new series of instructions has been cæsium, discovered by Professor Bunsen through means drawn up for the use of abstractors. Great efforts have of the old fame spectrum analysis. What a refined and been made to publish the younal within the first week of exquisite spectrum , too, does not cæsium present in the each month. The ventilation of the meeting room has lamp Aame! So many lines it has, and all of them thin, been much improved by the combined investigations of Mr. sharp, classical almost in the orange, yellow, green; and Perkin and Dr. Russell, and alterations suggested by them. then two gorgeous ones in the blue, but both of them so A new plan of choosing the President has been adopted clearly defined, so admirably distinct, that I, in my small this year. As the Faraday Lecture uccurs only once every way, should have long ago established cæsium as my three years, whilst the President is elected for two years, piime standard reference in all lamp spectroscopy, if it it was suggested that it would be beiter to elect some yad not been so dreadfully expensive.

Fellow who has already filled the office of President for to Yet what becomes of this most valuable, almost in- one year, so that the Faraday Lecture would occur in the valuable, element cæsium when promoted from mere second year of the next President's tenure of office. A flame to the higher temperature of the condensed ele&ric separate Report of the Research Fund is submitted, the spark? Alack! there is only then to be seen one faint President suggesting that a portion might, with peculiar solitary line, which has nothing in common with its de fitness, be devoted to the accurate determination of che. paited brethren, and but little beauty of its own. Withmical constants. A short biography of each of the Fellows such a spectral calamity befalling poor cæsium, I have deceased was then read, viz., o M. Malaguti (Foreign been watchsully careful, in any attempted increase of the Member) Messrs. W. Baker, A. Bird, W. A. Lyttle, W.A. brilliancy of other spectra, to interfere as little as possible Stewart, and J. Wiggin. The President concluded his with their temperatures. And it is simply because I have address as follows:-" While there is much to encourage recently proved the practical efficiency of a very easy ! us in the progress of the past twelve months, I think I method of accomplishing at least a considerable amount only express the general feeling when I say that we ouglit of brightening up, without any increase of heat whatever, not to feel satisfied with present attainments. The Society in both flame and spark spectroscopy, that I have ven exists" for the general advancement of Chemical Science;" tured now to lay the said method for merely what it this means both the encouragement of research and may be worth, and to what extent it may be new, before the diffusion of the knowledge of new discoveries. With the Royal Scottish Society of Aris.

regard to the promotion of research, as our members now (To be continued).

exceed 1000, and the laboratories cf our land are growing

in importance, we may surely look for a larger amount of PROCEEDINGS OF SOCIETIES.

original work in coming years: we should also seck,

not only to add to previous knowledge, but to increase . : 120ml., lu gun y

what I may venture to term the scientific culture of the responent . CHEMICAL SOCIETY.

workers. In our laboratories we are isolated, and are apt W S .... Monday, March 31, 1879.

to look upon our own pet subject as of prime importance ;

but when we meet in these rooms, or tura over the pages Dr. J. H. GLADSTONE, F.R.S., President, in the Chair. of our journal, we are carried away to many different

fields of thought in succession. This promotes largeness This was the Anniversary Meeting of the Society. . . of view; and must react favourably upon the cultivation of

The PRESIDENT presented his Annual Report on the lour individual tornet of the great field. I trust that our state of the Society. The state of the Society affords. Society.will never devote its çnergies too exclusively to

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