Imatges de pàgina

May 10, 1862.3

Royal Institution of Great Britain.


I might add, that it always takes place if care is taken from one another in their refrangibility. But we noticed to mix with the liquid a very small quantity of one of that this solar spectrum is not continuous,-that it those liquids in which spontaneous fermentation has is intersected by dark lines which run through the been obtained.

whole length of the spectrum, and which occur always in Thus far there is nothing remarkable; it is a tartrate

sunlight. We noticed that these bands occur not only in which ferments. The fact is known.

direct sunlight, but also in reflected sunlight-in the light But apply this mode of fermentation to the para

of the planets, and that these same bands do not occur in tartrate of ammonia, and, in the preceding conditions, it

starlight. Hence Fraunhofer, as early as the year 1814,

stated that these lines observed in the spectra of the sunferments. The same yeast, or leaven, is deposited. All

and planet-light must in some way bave their origin in the indicates that things go on absolutely, as in the case of

sun.' We then proceeded to notice the properties of the the right tartrate. If, however, we follow the steps of the light given off by artificially heated bodies. We saw that, operation with the aid of the polarising apparatus, we with the exception of phosphorescence, light is given off very soon perceive marked differences between the two only when a body becomes heated; and we divided artioperations. The liquid, at first inactive, possesses a ficial light as given off from heated substances into two rotary power sensibly to the left, which augments little great classes,-namely, that kind of light which is given by little and attains a maximum. Then the fermentation off when a solid or a liquid is heated, and that kind of is suspended. There is no longer a trace of right acid in light which is given off when a gas is heated. We saw the liquid, which, evaporated and mixed with its volume that when a solid or a liquid body becomes luminous it of alcohol, immediately furnishes a fine crystallisation of gives off light of every kind between certain limits—that left tartrate of ammonia.

its spectrum is continuous; whereas the light given off by We remark at first in this phenomenon two distinct

a glowing gas is not of every kind--that such light prothings; as in every fermentation, properly so called, there

duces a broken spectrum ; and thus we learnt that it was is a substance which is chemically transformed, and cor

possible to distinguish, by examining the light given off

by such glowing gases, between the kinds of gas which relatively, there is a development of a body possessing

were made to glow, but that we could not in the case of the manners of a mycodermic vegetable. Elsewhere, liquids or solids decide by the examination of the light and it is this which it is important to note at this time, | what substance was heated; and thus we arrived at a the yeast which causes the right salt to ferment, respects knowledge of the possibility of founding the science of the left salt, in spite of the absolute identity of the spectrum analysis-a science which will teach us what the physical and chemical properties of the two right and chemical nature of a substance is by simply looking at the left tartrates of ammonia, whenever they are not sub- kind of light given off by its glowing vapour. jected to dissymmetric actions.

I propose in this lecture to notice-for I cannot do more Observe, then, molecular dissymmetry proper to than notice-Bome of the applications of the principles organic matters intervening in a phenomenon of the

of the which we laid down in the last lecture, to the analysis physiological considerations and studies the idea of the

of terrestrial matter ; for we find that we obtain, by the influence of the molecular dissymmetry of natural application of these principles to the examination of the organic products, of the great character which esta

matter which composes our globe, a knowledge which

is as perfectly unlooked for and novel as it is interest. blishes, perhaps, the only well-marked line of demarca

ing-information concerning the properties and chemical tion which can be placed at the present time between

composition of the matter constituting the globe which the chemistry of organic nature and the chemistry of we inhabit. inorganic nature.

We must remember that what we require to do in order XIII. Such are, gentlemen, in their totality, the to obtain such a knowledge of the constitution of terres. labours with which I have been charged to entertain trial matter, is to obtain this terrestrial matter in the conyou.

dition of a glowing gas. Now, we may divide, for the sake You have learned, as we advanced, why I have of illustration, the matter composing the globe into three entitled my exposition, “On the Molecular Dissymmetry classes, -that matter which is made gaseous and which of Natural Organic Products.” It is, in fact, the theory

becomes luminous near the temperature of the coal-gas of molecular dissymmetry that we have just established;

flame; that matter, in the second place, which is volatile one of the highest chapters of science, entirely unfore

at a much lower temperature than that; and thirdly, that seen, and which offers to physiology entirely new,

matter which is volatilised, and becomes luminous at a

much higher temperature than that of the gas flame. distant, but certain horizons.

Thus, for instance, if I place a piece of clean platinum wire in this gas flame for a few moments, we shall observe

that it does not impart any colour to the colourless flame. PROCEEDINGS OF SOCIETIES. For a moment it does impart a colour, for a reason which I

shall have to explain. The platinum. itself does not give ROYAL INSTITUTION OF GREAT BRITAIN.

any colour to the gas flame because it is not volatile at the temperature of the flame, and we do not get any platinum

gas. But if I place another substance in this flame; for A Course of Three Lectures on Spectrum Analysis, by

instance, a piece of common salt, we shall see that this Dr. H. E. Roscoe, Professor of Chemistry in Owens

flame is coloured of a peculiar tint, owing to the fact that College, Manchester.

the godium is here volatilised, and that it becomes luminous,

and gives off its peculiar and characteristic kind of light, LECTURE II. (Saturday, April 5, 1862.)

namely, yellow. Now, by heating the platinum to a much LADIES AND GENTLEMEN,-In our lecture last Saturday higher temperature, we can get the peculiar light which afternoon we investigated the properties of white colar it gives off. Thus, for instance, I have here a platinum light. We saw that the sunlight which produces upon pole, and by passing an intense electric spark through this, our eye the impression of whiteness is, in reality, composed I obtain the platinum, as we shall see in a subsequent part of an infinite number of different coloured lights; and wel of the lecture, in a state of luminous vapour, and then we obtained, when we passed this white solar light through a find that the platinum also gives out the light which is triangular piece of glass, that which we called the solar spec- peculiar and characteristic for platinum alone, and which trum- broad band of variously coloured rays differing I no other body gives off,


Royal Institution of Great Britain.

CHEMICAL NEWS, 1 (May 10, 1862

That peculiar chemical substances produce in the flame barium; all we have to do is to place the substance which peculiar colours has long been known, and this fact is we know to be barium in the one flame, and to place the used by the chemist as a means of detecting such sub- substance which we suppose to be barium in the other : stances. Thus, for instance, I will here show you a | if on looking through the telescope we find that these two number of such differently coloured flames; here we sets of lines actually coincide that the lines of the subcan produce the luminous vapour of a number of these

Sur of a number of these stances which we know to be barium coincide exactly substances. I can here produce the characteristic yellow with the lines of the substance which we suppose to be flame of sodium. If I bring the salts of potash into this barium,- We then arrive at a very distinct knowledge that flame I can produce the peculiar colour given by all those the substance is really what we suppose it to be. If we salts-a peculiar purple colour. Here I have the peculiar examine with such an instrument as this, which is the colour which is produced by a very interesting body with latest form of Bunsen and Kirchhoff's apparatus, such a which we shall have to do in a subsequent part of the flame as any of those we see burning before us, we observe lecture-one of the new alkaline metals discovered by what is represented very faithfully indeed by these painted Bunsen, rubidium; and this is the flame coloured by the diagrams. If we look at the yellow sodium flame, we other new alkaline metal, cæsium, also discovered by notice that the sodium spectrum consists of one single Bunsen. Here we have lithium, which produces this bright yellow line, which, when we examine it more magnificent red colour. Here we have the green produced carefully with a larger number of prisms, we find is split by barium. All the salts of barium tint the flame of this up into two lines. Now, all the sodium compounds yield beautiful green colour. Here we have the red produced this peculiar spectrum; and nothing we know of, besides by strontium. Here we have the orange produced by sodium and its compounds, will yield it. Potassium, calcium, and here I will produce a peculiar blue flame by which produced the purple flame we saw here, gives us a a substance which differs entirely from these in pro spectrum consisting of a portion of a continuous spectrum, perties—the non-metallic element selenium. If I bring with a bright line in the red and another in the violet. selenium into the flame, we shall see that this body One of these lines is known as line alpha of potassium, imparts to the flame a very peculiar and beautiful blue and the other as the beta of potassium. These lines are not colour. It is extremely volatile, and only lasts for a few seen in any other substance, and they are seen in every seconds. Further on we have the peculiar blue colours potassium compound from which we can obtain this communicated to the flame by copper and by boracic acid. luminous vapour. Proceeding onwards, we find that we

I can show you the same thing in various ways. Here, see the spectrum of lithium, consisting of one bright red for instance, I can produce a much larger flame, and show and one orange line not so bright; and these three lower you the colour of the same salts. [A large gas flame was paintings-strontium, calcium, and barium-represent the produced from a perforated jet of about three inches in spectra of those three alkaline earths. What we notice diameter, and urged by a strong current of air. Pumice. when we look at these flames through the telescope is stone dipped in solutions of the chloride of sodium, exactly what is represented on that diagram, potassium, barium, strontium, calcium, and lithium, were Now, we may ask ourselves, “ This is all very well, bui then held in the flame, the colours imparted by those what improvement is this method of analysis upon our substances being thereby again made evident.]

ordinary chemical methods What benefit is it to us that I will show you one more illustration of this with these barium gives us these peculiar bands, that strontium yields papers. These are papers-gun-papers, in fact, which certain different bands, that calcium produces Others have been soaked in nitric acid, and which have then been again. We know that the reactions of calcium, barium, steeped in solutions of these various salts. Here you see and strontium are very different, and we can easily detect we shall have rather a quick combustion, but by reflection these substances by the ordinary chemical methods." The on the white screen the colour will be shown very well. answer to this is, that this method is far more delicate than (The lecturer then burnt gun paper which had been dipped anything which has been hitherto used; that by means of in solutions of the chlorates of the following substances: this reaction we can detect such minnte quantities that the sodium, potassium, barium, and strontium.]

delicacy of the method is almost past belief. I am sorry to As I have said, it has been long known--that these say that I forgot to make an experiment with sodium to various substances produce certain colours when brought show you the delicacy of this process, because I am afraid into the flame. But if we now examine more closely that we have now so filled the room with that substance what goes on when we have these variously-coloured that we cannot get the reaction so delicately as I should flames burning before us, and what exact kind of light like. I am afraid the flames will all burn now with the is given off ; that is to say, if we examine the spectra sodium reaction. I want to show you that dust contains of these differently-coloured flames, we find that we sodium,- that we cannot take up a substance which does obtain very much more information concerning the matter not contain sodium ; and if I heat this platinum wire, we than we do in this simple way by looking at the flames them shall see that it contains sodium. The flame becomes disselves, We look through a prism, or we employ Kirchhoff and tinctly yellow; and if I pass it between my fingers, you Bunsen's more perfect arrangement, which you see here in will see that my fingers contain sodium, and this you will the actual instrument before you, or here in the drawing ; see by the yellow colour imparted to the flame. I do not and we place a bead of the salt, the colour of whose light know now whether the dust from my coat will show the we wish to examine, in the flames here in front of this slit, presence of sodium ; it certainly would if the flame were as indicated in the drawing. I here bring a bead of chloride not tinged by the sodium which is already in the atmoof barium into one of these flames placed at one side of the sphere. I will try my coat. [The skirt of the lecturer's slit. The green light thus produced falls upon the small coat was dusted near the flame, and the presence of prism placed over the upper half of the slit, and it is sodium in the coat-dust was rendered evidert.] This is thereby refracted so as to pass into the tube and through not because it is the coat of a chemist; the dust from a the large prism. Into the other flame, placed directly in book will show us the presence of sodium. You see that front of the elit, I bring a bead of chloride of strontium, there is sodium in the dust of this book; in fact, every and the red light which this produces passes directly substance contains sodium, and therefore we can under. through the lower half of this slit on to the prism. In this stand how Bunsen could recognise the 180 millionth part way we obtain two spectra, one in the upper half of the of a grain of sodium, for this was the small quantity field of the telescope, the other in the lower half; and we that Bunsen and Kirchhoff found could be easily des are thus enabled to compare very beautifully indeed the tected. But not only can we detect such minute traces spectra which we wish to examine. Suppose, for instance, of substances, but we thus gain important information that we want to know whether a substance really is respecting the distribution of bodies. In illustration of

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this, I may mention that lithium-the body which gave lines are less refrangible than the potassium line, and these us that magnificent red flame, and some of which we have red lines (pointing to the diagram) do not exist in the here-was only known to exist in a very few minerals ; cæsium spectrum. Bunsen has chosen two names for but Bunsen, on examining the spectra of various sub these two metals—cæsium from cæsius, a greyish colour, stances, saw that this red line, indicative of the presence and rubidium from rubidus, red, owing to lines of these of lithium, exists almost everywhere. He found it in the colours being characteristic of the presence of these two ashes of plants; and an experiment, which he is fond of metals. showing, as illustrating the wide diffusion of lithium, is Here we shall get the sodium spectrum; but I warn you that of holding the end of the ash of a cigar in a colourless that you will see other lines besides those given by sodium. gas flame, and showing his friends the occurrence of the The bright orange line is due to sodium. The sodium specred lithium line, when the flame is observed by means of trum produces this bright orange line, which is alone seen this instrument. We thus see that lithium is contained in here when we look at it through the more delicate instruthe ashes of tobacco, in the ashes of many other land plants, ment, and use a finer beam of light and a finer slit. We in the oldest formations, in granite, and in the blood of then see that the sodium spectrum consists solely of two animals. Instead of being, as was formerly supposed, a bright yellow lines, which are separated by a very, very most sparingly-diffused substance, it is one which occurs slight interval, and each of which is as fine as the finest almost everywhere ; but owing to the small quantity of the spider's web. We cannot, unfortunately, exhibit the substance present, it bad been overlooked by our rougher sodium lines in that way. There you see the splendid and less exact methods of research. The crowning point of spectrum in which the orange band of sodium is very this investigation is, however, that of the discovery of two markedly visible. The other lines are not those which we new alkaline metals by Bunsen. Bunsen, on examining have to attend to at present. It is impossible here, owing the alkalies contained in the waters of Dürkheim, in to the fact that our carbon points are impure, and cortain Rhenish Bavaria (he had previously separated, by che certain metals mixed with the carbon, to get the pure mical means, all the other bodies from the water, and spectra of the metals ; and with this smaller apparatus, the substances which were left could only be alkaline unfortunately, we cannot get light enough to throw the substances), saw, on looking at the spectra produced by spectra on to the screen. these, some lines which he had never seen in the spectra We now have the potassium spectrum, we still see the of any alkalies before ; and he said, “There is a new yellow band of sodium, because, as I have told you, sodium alkaline metal contained here; this appearance must be exists everywhere, and it is almost impossible to get the produced by some new elementary body;" for no other potassium pure; but we shall likewise see two other lines. substance which he knew of, or which he had examined, had There is the bright red band at one extreme end of the ever given these lines before. Now, in a very interesting spectrum, and a violet one at the other end. These two paper on these two new metals, which he calls rubidium are due to potassium. You notice also that the spectrum and cæsium,-for reasons I shall explain to you presently, | is continuous in the centre. -Bunsen says that from 30 grammes of the mother liquor Now, we will take a mixture of potassium and sodium ; he obtained only 1'2 milligrammés of the impure salts of such a mixture I have here. This mixture contains one these two new alkaline metuls. That was all he had to part of sodium and twenty parts of potassium, yet the begin with,-&bout the one-hundredth part of a grain ; yellow colour of the sodium will cover entirely the purple but still, so sure was he of this method, and so certain colour of the potassium; and when we look at the was he that his spectrum never failed him, that he set to flame with the naked eye we shall see nothing but the work at once and evaporated down 50 tons of this water yellow flame, which might be produced by pure sodium. to get some more of this substance. 44 tons yielded him (A portion of the mixture was held in the gas flame, to only 105 grammes of the chloride of rubidium, and 701 which a bright yellow tint was communicated.] You grammes of the chloride of cæsium; so that out of 44 tons see this flame is as yellow as if it were pure sodium, yet of water he got only about 200 grains of the mixed it consists of one part only of sodium and twenty of chlorides of these two new metals. Here I have a small potassium, But if we bring this mixture into the appaspecimen of the salts of cæsium, kindly sent to me by my ratus, and if we look at its spectrum, we find that the friend Professor Bunsen. I have, however, more of the light of the sodium is kept to its own position. We have rubidium salts, which now can be obtained in larger the bright yellow line of the sodium which does not quantities from the mineral lepidolite which I have men interfere with the lines of the potassium, and these tioned. Bunsen, then, by the inspection of the spectra of come out as distinctly as though no sodium were present at these new alkaline metals determined their presence, and all. By allowing the bright sodium line to appear only afterwards, having seen these lines, set to work to separate where it ought, we see both the potassium lines coming out the metals which caused them.

out most beautifully. I will, with your permission, first show you the spectra Bunsen most eloquently describes, in his Memoir on of potassium and sodium, and afterwards the spectra of the this subject, the spectra which he sees when he places in the new alkaline metals. Mr. Ladd will be kind enough to show flame a mixture consisting of the chlorides of potassium, us with the electric light these spectra; but you must not sodium, lithium, barium, strontium, and calcium, of each of suppose, ladies and ger.tlemen, that what we get on the which substances there is present only the one-thousandth screen is exactly what we observe when we look through part of a grain. He sees, first of all, the spectra of those Bunsen's apparatus, which is adapted specially for analysis; substances which are most volatile appearing; the salts of but the results are extremely beautiful and interesting, and, sodium, potassium, and lithium are first seen ; their spectra I think, we shall see the distinguishing difference between first come out, and these gradually fade away, and the the salts of rubidium and potassium. I will draw your spectra of calcium, strontium, and barium appear in all their attention, first of all, to the paintings representing the vividness. Now, unfortunately, I cannot show you this spectra which we are about to see. Rubidium and cæsium with the beauty in which it is seen in the instrument when both possess spectra analogous to the spectrum of potas- we allow the rays to fall on the retina; but you can see sium. The difference in the spectra is but small. The something which is very magnificent indeed. The mixture potassium, as I have told you, gives a partially continuous of all these chlorides together we now place in the carbon spectrum ; rubidium also gives a partially continuous cup, and on bringing the upper carbon in contact with spectrum ; and the cæsium likewise gives a partially con- | the mixture we shall volatilise the compounds, and we tinuous spectrum; but at either end of all three spectra shall obtain the super-imposed spectra of all these subwe find red lines in the least refrangible part, and violet stances. Mr. Ladd has now placed all the mixed chlorides lines in the most refrangible part; the two red rubidium l in the cup, and on making contact we shall have all the

CHEMICAL NEWS, 264 Royal Institution of Great Britain.

· May 10, 1862. lines appearing. There you see what splendid bands we Cæsium can be separated from rubidium by the solubility get now, and you will observe that some of the bands will of the carbonate of the former metal in alcohol. The gradually disappear, the light remaining constant; and atomic weight of rubidium is 85:36, that of cæsium is others will appear with greater brilliancy, because the | 123.35. more volatile of these salts are driven off. There you We cannot see the end to which the application of this notice the bright green bands of the barium. That splendid principle may lead. During the first few months it has blue line is produced by strontium. Here we have the led to the discovery of these two new metals, and we have sodium; that is the green line of calcium ; here we have not only their spectra examined, but also are acquainted the bright red line of lithium,

with most of their salts. Another observation which Now, how did Bunsen separate these new metals from shows us how rich is this field of inquiry, is, that a one another, and from the old alkaline metals ? I must new elementary substance has probably been discovered give a moment to this point. In the first place, unless we by Mr. Crookes. He has not yet succeeded in preparing could examine the spectra of cæsium and rubidium, we a large quantity of the body, and thus proving its chemical probably should never have discovered their existence at characteristics distinctly, but he has prepared a substanec all. There is no doubt now that one at least of these which seems to differ in its chemical characters from all newly-discovered substances has been handled by chemists the other elements, and gires a totally different spectrum, before, but mistaken for potassium, in a certain mineral consisting of one bright green line. Much is not known called lepidolite, which was known to contain lithium, and at present about this substance, but there seems very little has now been found to contain a large quantity of rubidium. | doubt that it will turn out to be a new chemical element, to Rubidium and cæsium are so much like potassium in their be added to the rather large family of elementary bodies. chemical characters that, if it were not for this difference Now, although Bunsen and Kirchhoff are the real disin the spectra, we should never have succeeded in separat. coverers of this method, because they carried it out with ing one from the other, or in detecting any difference all due scientific accuracy, and placed it on a sure between these substances when they were present together. foundation, yet we must not suppose, because they worked

I can show you that rubidium and potassium are it out, the ground was, before them, absolutely untrodden. closely analogous. Here we take a solution of chloride of No great discovery is made all at once. There are always platinum. We know that it produces with potassium stepping-stones by which such a position is reached, and it compounds an insoluble precipitate, and thus we dis- is right to know what has been done previously, and to give tinguish these from the sodium compounds with which no such credit, as is their due, to the older observers. Now, such precipitate is produced. We shall at once get, as the first notice we have of the property of these coloured you will see, a quantity of this bright yellow precipitate flames was made by Thomas Melvill in the year 1752. of the double chloride of platinum and potassium.

He observed the yellow light given off by sodium vapour, Exactly the same thing we shall see will happen with but he did not know that it was due to soda, though he rubidium. Here I have a solution of the chloride of observed that a mono-chromatic light was given off. Sir rubidium. I add a few drops of this solution of chloride of David Brewster, in the year 1822, proposed a mono-chroplatinum, and immediately we get a precipitate of the matic lamp; but the original observation was due to double chloride of platinum and rubidium. We cannot Melvill. Herschel, in the year 1822, observed the spectra in the outward appearance see any difference between the of several coloured flames, and in an article on Light precipitate formed by the rubidium and that formed by in the Encyclopædia Metropolitana, in the year 1827, the potassium. This is one of the reactions by which we Herschel says, " The colours thus communicated by distinguish potassium from sodium, but you see we can- different bases to flame afford in many cases a ready and not in this way distinguish potassium from rubidium. neat way of detecting extremely minute quantities of We can make a similar experiment with tartaric acid. If them." But it is to Fox Talbot, a gentleman well-known we take some chloride of potassium and some chloride of to us as one of the first investigators of the beautiful art of rubidium, and add to each some tartaric acid, we shall photography, that we owe the first valuable suggestions obtain with both a white precipitate of the insoluble respecting this subject ; and it is interesting to remember bitartrate.

that Talbot made his experiments in the laboratory of But we can distinguish these new metals from potassium, this Institution, under the guidance of Mr. Faraday. and separate them by a difference of property which is Writing in the year 1826, he says: — The red fire exhibited by these platinum salts. We can distinguish of the theatres, examined in the same way, gave a them in this way: Here I have a solution in water of the most beautiful spectrum, with many light lines or double chloride of potassium and platinum. I will place maxima of light. In the red these lines were more some of this in both of these glasses. You will notice that numerous, and crowded with dark spaces between," when I add some of the chloride of potassium to this (the [these are the strontium lines which you see on the diapotassium bichloride of platinum) we obtain no further grams there]" besides an exterior ray greatly separated precipitate; it is impossible that we should thus obtain a from the rest, and probably the effect of the nitre in the precipitate; but if we add some chloride of rubidium to composition.” [This really is due to the nitre.] “In the The potassium bichloride of platinum solution, we shall get orange was one bright line, one in the yellow, three in the at once a yellow precipitate showing that this double chloride green, a very bright one in the blue, and several that were of potassium and rubidium is much less soluble than that fainter." The blue line which he mentions was the blue of potassium and platinum. This is the way in which Bunsen strontium line which you saw, and concerning which I had separatedrubidium and cæsiumfrom potassium. Bunsen then hoped to speak, but I fear that I must defer that part of my investigated the salts; and we now have a Memoir, written subject. The bright line in the yellow is caused, without by himself and Kirchhoff-the second Memoir on Spectrum doubt, by the combustion of sulphur." Talbot got wrong Analysis—which contains a very elaborate and beautiful there, as did many other early observers. They did not description of their researches on this subject. We are suppose that so small a trace of sodium could produce now acquainted with the nitrate, with the sulphate, with that yellow light; and even Tallot says that no doubt the the carbonate, with the oxalate, with the hydrate, and yellow line must be caused by the presence of water. He even with the two new metals themselves ; so that we continues :-" If this opinion” (that is to say, the opinion have a chemical history of those two substances, which about the formation of these lines) " should be correct, we must teach in future in all our classes. I must mention and applicable to the other definite rays, a glance at the also that both rubidium and cæsium form salts which are prismatic spectrum of a flame might show it to contain isomorphous with the potassium salts; they crystallise in substances which it would otherwise require a laborious the same form, and they possess an analogous composition. chemical analysis to detect." That was written in

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March. 1826. In February, 1834, he writes : -" Lithia | 40931. 98. On December 31, 1861, the funded property and strontia are two bodies characterised by the fine was 28,6551. 178. 2d.; and the balance at the bankers, red tint which they communicate to the flame. The 9681. 168. 8d., with six Exchequer bills of 100l, each. former of these is very rare, and I was indebted to my A list of books presented accompanies the Report, friend Mr. Faraday for the specimen which I subjected to | amounting in number to 524 volumes ; making, with those prismatic analysis. Now, it is difficult to distinguish | purchased by the managers and patrons, a total of 524

rom the strontia red by the unassisted eye," volumes (including periodicals) added to the library in the (as you have seen here, in fact,) " but the prism displays year. Sixty-three lectures and twenty-one evening dis

between them the most marked distinction that can be courses were delivered during the year 1861. - imagined. The strontia flame exhibits a great number of Thanks were voted to the President, Treasurer, and 1. red rays well separated from each other by dark intervals, Secretary, to the Committees of Managers and Visitors, and

not to mention an orange and a very definite bright blue to Professor Faraday, for their services to the Institution ray. The lithia exhibits one single red ray." "Hence, during the past year.

I hesitate not to say" (says Talbot, writing in 1834) The following gentlemen were unanimously elected as is “that optical analysis can distinguish the minutest Officers for the ensuing year :

portions of these two substances from each other with as President—The Duke of Northumberland, K.G., F.R.S. much certainty, if not more, than any other known Treasurer-William Pole, Esq., M.A., F.R.S. Secretarymethod."

Henry Bence Jones, M.A., M.D., F.R.S. ManagersThe Sir David Brewster, in the year 1842, published some Rev. John Barlow, M.A., F.R.S.; William Bowman, Esq., interesting observations concerning the spectra of coloured | F.R.S.; Sir Benjamin Collins Brodie, Bart., D.C.L.. flames. Examining the coincidence of the bright metallic | F.R.S. ; Warren De la Rue, Esq., Ph.D., F.R.S.; George

lines and the dark solar lines, he saw-and this is Dodd, Esq., F.S.A. ; The Earl of Ducie, F.R.S.; John 3. an important observation - that this bright red line in Hall Gladstone, Esq., Ph.D., F.R.S.; William Robert e the potassium is a double line; and he noticed, in the Grove, Esq., M.A., Q.C., F.R.S.; Sir Henry Holland,

year 1842, that this bright red line of potassium is Bart. M.D., D.C.L., F.R.S.; The Lord Lovaine, M.P.: 13: coincident with, or has the same degree of refrangibility William Frederick Pollock, Esq., M.A. ; Lewis Powell, I as the dark line A in the solar spectrum. Now, this M.D., F.S.A.; Robert P. Roupell, Esq., M.A., Q.C.;

was observed also quite lately by Kirchhoff, and entirely in- Lieut.. Gen. Edward Sabine, R.A., Pres. of Royal

dependently of Brewster, and they both agree that the dark Society ; Colonel Philip James Yorke, F.R.S. Visitors 2-line A is coincident with the red line caused by potassium.

with the red line caused by potassium. | Neill Arnott, M.D., F.R.S. ; Hon. and Rev. Samuel Best: This has been lately denied by the French observer, M. George J. Bosanquet, Esq.; Archibald Boyd, Esq.

Morrenbut it seems to me that the researches of Bernard Edward Brodhurst, Esq. ; John Charles Bura TE: two such observers as Brewster and Kirchhoff, made goyne, Esq. ; Gecrge Frederick Chambers, Esq, ; Hon.

independently of each other, and, especially, at a distance Sir Charles Crompton, Justice of Queen's Bench; of eighteen years, must be correct.

Edward Enfield, Esq. ; Captain Frederick Gaussen; the Professor W. A. Miller, in the year 1845, took up the Duke of Manchester ; John MacDonnell, Esq.; Colonel e subject, and investigated the dark absorption bands pro- William Pinney, M.P.; George Stodart, Esq., Hon. Sir

duced by certain gases, and the bright lines in the spectra James P. Wilde, Baron of the Exchequer. of coloured flames. Diagrams of these spectra accompany

his Memoir, but they are not sufficiently characteristic to Denable us to easily distinguish the particular metal, though

CHEMICAL SOCIETY. in some cases they show lines which Bunsen's diagrams do not exhibit. In his observations he did not refer to

Thursday, May 1, 1862. in the application of these researches for the purpose of detecting the metals producing these bright lines. Here

Dr. A. W. HOFMANN, F.R.S., President, in the Chair. I have some representations of Dr. Miller's lines. This DR. T. ANDERSON gave a discourse “ On the Chemistry of is the barium spectrum ; this is the calcium spectrum ; Opium." Since the year 1803, opium had attracted the and this is the strontium spectrum, as drawn by him in attention of chemists ; of late years the principal point

the year 1845. You see they differ from those of Bunsen aimed at had been the preparation of morphine in a pure - and Kirchhoff, because Dr. Miller had a continuous state. In extracting the opium in order to obtain the spectrum at the same time. His flame was not a non bases it was better to use only a small quantity of water luminous one, as was the case with the one used by Bunsen heated to about 150° F., in which case all the narcotine and Kirchhoff.

would be dissolved out, and only woody fibre left; but if Ladies and gentlemen, I have already taken up the a large quantity of water were used, the narcotine was allotted time. I am sorry to say I had a great deal more left behind in the insoluble residue. The alkaloids existed to say, which I must defer to the next lecture. I may in combination with a peculiar organic acid called meconic add that I shall be happy to exhibit to those who stay, the acid, and another acid had been discovered in opium spectra of the new metals by means of the electric lamp. which was isomeric with lactic acid. The liquid obtained "After the lecture Mr. Ladd exhibited the spectra of by extraction with water was mixed with a certain quantity rubidium and cæsium. In the rubidium spectrum were of chloride of calcium, and the precipitated meconate of seen two bright violet bands, as well as the two charac- | lime separated, after which the solution was concentrated teristic red lines in the ultra-red portion of the spectrum. and allowed to stand, when hydrochlorate of morphine and The violet lines of the cæsium were also seen, and noticed hydrochlorate of codeine crystallised out; these bases to be less refrangible than those of the rubidium.]

could be easily separated by precipitation by ammonia, the codeine being soluble in water. It was gene

rally supposed that the codeine formed a double Annual Meeting, Thursday, May 1, 1862.

salt with ammonia, but from Dr. Anderson's experiThe DUKE OF NORTHUMBERLAND, F.R.S., President, ments this did not appear to be the case. The in the Chair.

mother-liquor from which the hydrochlorates had been The Annual Report of the Committee of Visitors for the deposited gave, on the addition of ammonia, a preyear 1861 was read and adopted. The amount of con- cipitate containing narcotine, papaverine, thebaine, and tributions of members and subscribers in 1861 amounted codeine, together with numerous resinous matters; the to 30131. 1os., the receipts for subscriptions to lectures were presence of the last-mentioned base in the precipitate was 7401. 119. 60.; the total income for the year amounted to romarkable on account of its solubility in water. On pi

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