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Royal Institution of Great Britain.

it into one of those colours that I say it is capable of quenching, it will become black. Now observe. Here in the red ray we have the red very beautiful indeed, but the green is made quite black. Now I move the flowers into the green portion-what are they now? Black. And here, again [moving the flowers into the red light], they are a beautiful bright red. The green light is much more intense to look at than the red light, but this substance is not capable of giving back the green light: it is only capable of giving back the red light. The consequence is, that when the green light falls upon it its colour is destroyed-we have darkness instead of light. Here we have three sticks of sealing-wax, beautifully red. What are they now? [Placing them in the green part of the spectrum.] Look at them now: the light shining on them is very intense, but the sealing-wax is quite black. Now, with regard to the influence of this coloured light upon the human countenance, I wish I could get some boy, in all the bloom of rosy youth, to let me try the influence of the light upon his cheeks. You would see how he would look in this green light. I wonder whether any of my pupils will volunteer. However, in the absence of a volunteer, I will take Mr. Anderson; he has a tolerably fair colour, you know. He will stand here, and I will illuminate his face. I dare say I shall succeed in making one cheek appear full of the bloom of youth, and in reducing the other to a state of almost death-like paleness. Let us see if that is not possible. [Mr. Anderson then walked slowly along the coloured rays of the spectrum.] There, you see his face is full of radiant bloom. As he passes along, you will find one side of his face will assume a very cadaverous aspect. He will go back again so as to show you the effect produced: by-andby his whiskers will become quite radient-now he is in the midst of the red ray-there, he is in almost the full splendour of boyhood.

CHEMICAL NEWS,
Feb. 1, 1862.

is most beautifully shown passing along the smoke of the room. Now, I want to examine that light which is thus given out by the copper, that is, I want to produce a spectrum of that light. And when I do so you will find that this spectrum, instead of being continuous, as in the former case, now consists of a series of brilliant bands of light, and in particular you will notice the very brilliant green bands produced by it. There you see the spectrum produced by the combustion of the copper, and the beautiful green bands we have already noticed, with the dark spaces between. I will now take another metal instead of copper. I will place a bit of zinc upon the crucible, and just be kind enough to bear in mind the kind of bands you saw with the copper; they were chiefly green, while those that you now see produced by the zinc are of a brilliant blue. You see the spectrum covered with these blue bands. Now, I will take a substance formed by the mixture of zinc and copper, that is, brass, and in the spectrum produced by the combustion of that brass I trust you will be able to see the bands of both the metals of which it is composed. You remember that copper gave a series of green bands, and zinc a series of blue bands, and I hope in the spectrum of the brass, if we are skilful enough to make the experiment aright, we shall see both the green of the copper and the blue of the zinc. In this way, knowing the character of the spectrum, we can tell the metals of which it is composed. Now, I want to show you another very beautiful experiment before we part. In the first place, I will show you the light produced by the combustion of a little sodium. I have here a portion of this metal, which I can cut with a knife, like cheese. I have here a lamp, giving a strong heat, but very little light, and I will take a portion of this sodium and put it upon a little platinum cup and hold it in the flame of this lamp, and then I think you will see that the sodium has the effect of giving a very intense yellow light indeed. Let us see whether we can produce this. At the best of times I have not much colour, but what little I have will certainly disappear if I cause this light to become more intense. That light does not only appear yellow, but it has actually no red in it at all. Look at the red sealing-wax, and at that bottle; that bottle contains iodide of mercury, which is of a brilliant red colour, but you see the red is now completely gone.

Now, I want to show you some of the spectra produced by the combustion of various kinds of metals. Hitherto, as you have observed, we have been dealing with a spectrum or coloured image, that was quite continuous from beginning to end, commencing with the red, and passing through various gradations to the extreme violet; it was continuous, there was no breach of the spectrum. I want now to show you some spectra where there are the most singular breaches of continuity, and to do this I I want, now, to make a very peculiar experiment. I operate thus:-You know the energy of this electric want to show you that that very yellow light which you current we use for our light; you know its power to render saw there is capable of cutting off the yellow light that metal white-hot, and even to dissipate it, and to reduce it emanates from the electric lamp. In order to do that, I to a state of vapour. Here I have a small piece of carbon, must first of all produce a continuous spectrum, such as and on the top of that I have scooped a little hole, and we had before. I want to get it very exact, for the into that hole I will put a little bit of metal. The metal experiment is an important one and worthy of some labour. I take is cadmium, well known to chemists. When I The experiment I am going to make is this. You saw that bring this little crucible close to our coal point and send beam issuing from the lamp, and the spectrum produced the current through it, the metal will become intensely from that beam upon the screen. I will send that heated; it will, in fact, be reduced to a state of vapour. spectrum through the sodium flame, and you will find In the first place, I want to show you the light produced that that flame will be capable of chiselling or cutting out by this cadmium. I will take away the ordinary coal with the greatest nicety the yellow portion of the spectrum. point which I have used for the light and place in its I want you particularly to observe the action of this piece stead this crucible of carbon. I will then place within it of sodium upon the flame. I want you to observe the this bit of cadmium, and bring down the upper coal point yellow part of that spectrum when I introduce this metal. to meet it. I want you to observe the beautiful coloured A certain duskiness will come over the yellow portion light produced by this cadmium. You have already seen there. Do you see how it cuts out the yellow of the the image of the coal points that we have worked with spectrum? Here, in the platinum spoon, I have a quanthroughout the lectures; I want to show you the distinctity of soda produced by the combustion of the sodium. tion between this image of the coal points and the image I will pour this soda upon one of the coal points, and you produced when we introduce a metal into the electric will then see that it produces a yellow line exactly where current. You see the splendid blue light produced by it formerly cut it out. Thus, the sodium flame is capable the combustion of the metal; it is entirely different from of absorbing those particular rays of light which itself the voltaic arc we have been hitherto operating with. can emi'. Instead of this cadmium I will take a little copper, and then a beautiful green light will be produced, due to the vaporisation, the reduction of the copper to a state of utter vapour. We may take gold or silver and produce similar effects. The green light issuing from the copper

I do not know that any more time remains to me to make experiments, but I will just carry you, in conclusion, to consider what has been done by experiments of this kind. When we take, instead of the electric light, the light of the sun, there are certain lines always

NEWS

observed in its spectrum. These lines have been compared with the utmost exactitude with the bands produced in the spectra of various terrestrial metals, and have been found exactly to coincide with them. In this way the actual composition of the sun has been proved by a very able man, a German. It is a wonderful thing to see the human mind, as it were, rising up to the sun itself, and being able to tell us, from the very lines that you see in the solar spectrum, the metals that are present in the sun. And not only so, but the experiments have led us to several conclusions regarding the nature of the sun; and we now know, which is very different from the conclusion adopted formerly, that the sun consists of a vast central solid or liquid sphere, in a state of high incandescence, burning hot. Round this sphere there is a great atmosphere, like a vast flame; the rays of the central solid or liquid portion of the sun have to pass through this fiery flame, and in that atmosphere certain of the rays are quenched and destroyed, exactly as the flame of the sodium quenches or destroys the yellow band of the electric light. Thus, from the lines in the solar spectrum, we can infer that iron, magnesium, and a great many other metals which are well known upon the earth are present in the sun.

NOTICES OF PATENTS.

895. Sizeing or Preparing Paper and Textile Fabrics in order to render them Waterproof, and to increase the strength thereof. R. A. BROOMAN, Fleet Street, London. A Communication. Dated April 11, 1861. FOR carrying out the objects specified in the title, the inventor claims the use of a mixture of carbonate of soda, lime, alum, and gamboge, which ingredients may either be incorporated with the pulp, or used subsequently to the manufacture of the paper.

The combination of gamboge and alumina is brownish yellow in colour, and must therefore communicate a somewhat dark tinge to the paper stuff.

911. Improvements relating to Ornamental Cotton Fabrics, having Turkey Red Grounds. G. GRAHAM, Dumbarton, N.B. Dated April 13, 1861.

THE mode of proceeding described in the specification, is substantially as follows:-The goods, after dyeing uniformly with turkey red, are subjected to pressure between lead plates, from which the required device is cut out. Thus partially protected, the red portions are bleached by exposure to chloride of lime and sulphuric acid. This having been effected, the material is well washed by a current of pure water passing through it, and then a mordant applied to the bleached surfaces, either wholly or partially, according to whether it is desired to leave some parts of the fabric white. The mordant may be any one of those commonly employed, but the inventor recommends the use of a mixture of acetate of lead and bichromate of potash, of a strength of about two and a-half degrees Twaddell. Logwood liquor, of the same gravity, is finally passed through the goods to produce a black dye.

It is manifest that numerous combinations of turkey red, white, yellow, and black may be obtained according to the mode of employing the series of perforated lead plates.

The second part of the invention relates to the production of continuous patterns, by the employment of blocks or rollers.

929. Manufacturing Silicate of Lime, or Hydraulic Cement. F. M. EDEN, Hare Court, Temple, London. Dated April 16, 1861. (Not proceeded with.)

FOR the preparation of a cement, (which is stated to be chemically identical with Portland cement,) the inventor

directs an intimate mixture to be made of chalk and clay. Carbonate of lime, or the same burnt to lime, may be employed indifferently. This mixture is then dried and burnt upon hot tiles or plates, or in suitable ovens or kilns, and the product (called silicate of lime,) ground to an impalpable powder.

Portland cement is usually prepared according to a process very similar to that under consideration, the mud from the river Thames being taken in preference to more compact clays. If chemically identical with the product of ordinary manufacture, the cement must contain a large proportion of alumina, derived from the clay, and would, consequently, be more correctly described by including the two bases in the expression, and calling it a silicate of alumina and lime.

927. Obtaining Light. F. GYE, Wandsworth Road. Dated April 15, 1861. In the arrangement of apparatus for the production of the lime light, the patentee claims the application of discs or plates of lime, instead of the usual balls or cylinders, and the imparting rotation to the same by means of a new combination of mechanism.

932. Improvements in the Manufacture of Nitric Acid and Caustic Soda. J. D. MALCOLM, Brixton, Surrey. Dated April 16, 1861. (Not proceeded with.) THE inventor mixes intimately one part, by weight, of nitrate of soda with three parts of fine clean sea sand, introduces the mixture into an earthen retort, and proceeds to distil as in the ordinary process of preparing nitric acid with the aid of oil of vitriol. The red nitric fumes are absorbed by water contained in a series of stoneware Woulfe's bottles, and the soda is said to remain in the retort partly in combination with silica, but principally in the form of caustic soda, which may now be recovered by washing the residual matter (sand and alkali), and evaporating the aqueous solution in order to procure caustic soda; the sand left insoluble may be dried and used in a repetition of the process.

The dis

A question of greater importance than the economisation of the sand has reference to the durability of the retorts alkali, the destructive influence of which would even be themselves under the corrosive action of so powerful an for the distillation under these circumstances. materially assisted by the elevated temperature required tillation of saltpetre with sand and clay was precisely that process which led to the first discovery of aqua fortis. It manufacture of nitric acid on account of the partial dehas not, however, of late years been resorted to for the composition of the product at the high temperature at which it is liberated. As an illustration of the antiquity of this method, we quote from Bishop Watson's Essays,' published in 1789,-"It is certain that the nitrous acid may be disengaged without the assistance of the vitriolic acid: thus I remember having many years ago obtained a very strong fuming acid of nitre by distilling nitre with white sand."

Grants of Provisional Protection for Six Months. 2917. Francis Puls, Francis Terrace, Hackney Wick, London, Improvements in treating fatty and oily matters."-Petition recorded November 20, 1861.

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3027. Andre Marie Augustin Pichery and Pierre Louis Danais, Nantes, Loire Inférieure, France, "Improvements in hermetically stoppering or covering jars, pots, vases, and other like articles."-Petition recorded December 3, 1861.

3076. Balthasar Wilhelm Gerland, Newton-le-Willows, Lancashire, “Improvements in the manufacture of sulphate of copper and other salts of the same metal."-Petitions recorded December 7, 1861.

1 Chemical Essays. Vol. I. p. 253.

70

Miscellaneous-Answers to Correspondents.

CHEMICAL NEWS, Feb. 1, 1862.

3142. Eduard Claude Barbotte de Beaulieu, Avallon, a social gathering of many having the same tastes and Yonne, France, "Improvements in apparatus for extracting objects, and, therefore, the same sympathies. The anatomy gold dust from auriferous sands." of an insect, too, is a more harmless occupation than the 3150. Emile Cajot, St. Servais, Belgium, "Improve-minute dissection of a neighbour's natural history. Tea ments in the treatment of pyrites for the manufacture of iron."-Petitions recorded November 14, 1861.

3195. Vasco D'Almeida, Nottingham-street, Marylebone, London, "An improved mode of obtaining colouring matter applicable to dyeing skins, silk, wool, and other fibrous materials." A communication from Edward Smith, Place Cruzquebrada, Lisbon.

3225. Francois Laurent and John Casthelaz, Rue St. Croix de la Bretonnerie, Paris, "Improvements in the manufacture of colouring matters."

3232. Joseph Schloss, Cannon Street, London, "Improvements in envelopes for containing photographic portraits and pictures."-A communication from Simeon Schloss, Paris.

3257. William Edward Newton, Chancery Lane, London, 'Improvements in the manufacture of cube sugar."-A communication from Gustavus Finken, Brooklyn, King's County, New York, U.S.

3259. Alexandre Isaac Austen, Millwall, Middlesex, "Improvements in the manufacture of night lights."Petitions recorded December 30, 1861.

CORRESPONDENCE.

Manufacture of White Lead.

To the Editor of the CHEMICAL NEWS.

SIR,-If your correspondent "Subscriber," in your last Number, will favour us with his address, we shall be happy to supply him with white lead (the pure carbonate), either in a dry state or ground in linseed oil, perfectly

fine and free from the defects he mentions.

We are, &c.

W. W. AND R. JOHNSON AND SONS. White Lead Works, Limehouse, London.

MISCELLANEOUS.

Chemical Society. The next Meeting of this Society will take place on Thursday, the 6th inst., when the following Papers will be read :-Mr. Adie, "On Ground Ice." Dr. Bence Jones, "On Crystalline Xanthin in Human Urine." Mr. A. H. Church, "On Silica." Professor Bloxam, "On Arsenic in Sulphuric Acid."

Royal Institution.-The following Lectures will be delivered in the ensuing week :-Monday, February 3, at two o'clock, General Monthly Meeting. Tuesday, February 4, at three o'clock, John Marshall, Esq., "On the Physiology of the Senses." Thursday, February 6, at three o'clock, Professor Tyndall, "On Heat." Friday, February 7, at eight o'clock, T. H. Huxley, Esq., "On Fossil Remains of Man." Saturday, February 8, at three o'clock, Rev. A. J. D'Orsey, " On the English Language.'

Adulteration of Food.—Dr, Letheby, the Medical Officer to the City Commission of Sewers, states in his quarterly report that no application has been made to him during the quarter for the analysis of food or dri k, and he adds that "it is to be feared, from the experience of the last six months, that the Adulteration of Food Act will become a dead letter."

Science a Civilizer.-Dr. J. Bullar at a recent meeting of the Southampton Microscopical Society, said :"The social aspect of our Society commends it. It is a pleasant way of spending an evening where there is a scientific object of natural interest, and, at the same time,

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and coffee, pleasant chat with those of like tastes, and then the table covered with microscopes and specimens explained by one and passed round for each to examine, calling out animated talk on subjects worth discussing, or a short paper read and discussed on the subject illustrated, are civilizing. For science is a civilizer. It refines the tastes and elevates the thoughts, as it is the search after truth for truth's own sake. And in this age, when the progress of the nation and of the world is estimated by the moneyvalue of exports and imports (and in this aspect the world's progress is prodigious and annually increasing), the danger must lie in estimating all things in reference to money rather than to truth. Now, science is a counteracting force. It neither brings wealth to its true cultivators, nor can wealth buy scientific tastes or scientific fame. It belongs to a higher region than the diggings.' It must breathe a purer ether, a diviner air.' And those who are engrossed in commerce would often do well, for their own content and happiness, by seeking in the recreations of science a complete change of action, thought, and feeling. Obviously the eye service which the microscope requires, trains the eye to minute and discriminative observation, and the hand to delicate accuracy. It leads on, if used scientifically, to the improvement of the scientific powers. The memory, the investigation of causes, the estimation of evidence, the power of distinguishing and of generalizing may be called into activity. But the mind has other and deeper needs than these. The senses lead to the awakening and culture of deeper powers inherent in the soul itself, and the microscope may excite and cultivate, not only the sense of the Constable, the landscapetrue, but of the beautiful. painter, said that, pictorially, nothing in nature was ugly; and surely we may say the same microscopically. The higher the magnifying powers, the more minutely extensive the investigations, the more beauty do we see. Even in the unhealthy secretions-in what look to the unscientific eye like repulsive fluids, in the very disorganisations which slowly ruin this goodly human frame, the microscope discovers forms of the highest geometrical accuracy, as well as of the most delicate beauty. And this beauty and consummate finish are everywhere, and are found fart er and deeper as our powers increase of observing them. Here, too, at every step we find the limitation of our own powers, and the illimitable field of nature; the infinite contrasting with the finite, teaching us the moral lesson of science-humility.' "'

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ready, price 128., by post, 12s. 8d., handsomely bound in cloth, goldVol. IV. of the CHEMICAL NEWS, containing a copious Index, is now lettered. The cases for binding may be obtained at our Office, price Is. 6d. Subscribers may have their copies bound for 28. if sent to Vols. I. II. and III. can still be had. Vol. V. commenced on January our Office, or, if accompanied by a cloth case, for 6d. A few copies of 4, 1862, and will be complete in 26 numbers.

exchange copy and much regret that it has not arrived. Enquiries American Journal of Pharmacy We have regularly forwarded our shall at once be made on the subject. Far from declining to exchange, there are few periodicals which we receive with so much pleasure as our Transatlantic contemporary.

attend to it. F. W. Joy.-The matter has been referred to our publisher, who will

J. Horsley-The controversy had better cease. Subscriber.-We believe the process to be impracticable. If not, it would, however, be terribly expensive.

Erratum.-Page 52, line 7, from bottom, for "chloroform" read "chlorine."

THE CHEMICAL NEWS.

VOL. V. No. 114.-February 8, 1862.

SCIENTIFIC AND ANALYTICAL CHEMISTRY.

On the Nascent Oxygen Tests for Aniline, by H. LETHEBY, M.B., M.A., Ph.D., &c., Professor of Chemistry and Toxicology in the London Hospital College.

IN the course of the last twelve months I have had to investigate, on behalf of the Coroner, two cases of accidental poisoning by nitro-benzole; and finding that this compound was changed in the animal body into aniline, my attention was directed to the most delicate means for discovering the presence of that alkali. At a future time I will seek an opportunity of describing the process for extracting the aniline from the stomach, tissues, and urine; but having procured it, I found that nascent oxygen, from whatever source it was obtained, gave to aniline a rich blue, violet, or red colour, according to the proportion of oxygen acting and the strength of the acid solution containing the alkali. The best means of applying the test is by the agency of the galvanic battery. If a single drop, or even half a drop, of a solution of part of aniline in 1000 of dilute sulphuric acid (1 of acid to 7 of water) is placed on a clean piece of platinum, and touched with the negative pole of the galvanic battery (a single cell of Groves' arrangement) while the positive pole is in contact with the platinum, the liquid acquires a bluish, then a violet, and finally a pink colour. If the sulphatic solution of aniline is stronger, or the drop is concentrated on the platinum foil by evaporation, the colour is of a deeper blue, and by using theth of a grain of aniline with a drop of dilute sulphuric acid, consisting of equal parts of acid and water, the galvanic test gives a rich blue or purple blue reaction of considerable intensity.

This result is very much like that which I have described as the galvanic test for strychnia,' but the two alkaloids are distinguished, not merely by the volatility of aniline and its appearing in a medico-legal inquiry in the distillate from the suspected matters, but also by the circumstance that while strychnia requires the concentrated acid to show its violet colouration on platinum, aniline is best seen with the dilute acid.

Other sources of nascent oxygen may likewise be made available as a means of discovering the presence of aniline, but they are not all equally sensitive. The Tougth of a grain of aniline in half a drop of dilute sulphuric acid (1 to 1) on a white plate will gradually become blue if it be treated with a little peroxide of lead or red prussiate of potash; but it requires twice this quantity of aniline to show the tint with peroxide of manganese or bichromate of potash, and still more is required to produce a marked and decisive blue or purple reaction with peroxide of hydrogen, or peroxide of

1 Vide Lancet, June 28, 1856, p. 798, and Chemical News, vol. ii., p. 3.

barium and sulphuric acid, or a solution of chlorine or chloride of lime.

This, however, is the general fact, that nascent oxygen from any source may be made the means of discovering it imparts to the alkali, and that of all these sources of the presence of aniline by the blue or violet colour which oxygen that from the positive pole of a galvanic battery is the most sensitive and the most manageable.

Finally, I may observe that these results from galvanic oxygen indicate the rationale of the action of many of the substances which have lately been patented for the production of aniline blues, purples, and reds; and by operating on a salt of aniline in dilute sulphuric acid in a porous cell, so as to prevent the nascent hydrogen from the negative pole of the battery influencing the effect produced by the oxygen at the positive pole very brilliant effects may be obtained.

On the Analysis of Mixtures of Potash and Soda in Neutral and Alkaline Solutions, by M. MOHR. THIS method is based upon the conversion of the potash into cream of tartar, and the estimation of the cream of tartar by a standard alkaline solution.

When the potash is in the state of carbonate, the operation is as follows:-The weighed potash is dissolved and saturated with powdered tartaric acid taken from a vessel which has been weighed beforehand. When the solution is saturated, there is added to it as much more tartaric acid as has been used: a slight excess of tartaric acid is of no consequence, the solubility of bitartrate of potash in tartaric acid not being very great. This solution is evaporated to dryness on a water-bath, and the residue extracted with a saturated alcoholic solution of cream of tartar. This is thrown upon a filter, washed with the same alcoholic solution, and then estimated.

When the potash is in the form of a neutral salt, tartaric acid cannot be used, since this acid sets the mineral acids at liberty in which the bitartrate is partially dissolved; it must, therefore, be contrived that the mineral acids remain combined. All neutral salts of potassium are changed on contact with bitartrate of soda into bitartrate of potash and a soluble soda salt. The solution is concentrated and evaporated to dryness; the residue extracted with alcohol saturated with bitartrate of potash placed upon a filter, and washed as before.

The difficulty consists in seizing the exact moment when there is sufficient bitartrate of soda added to decompose the potash salts. It is, however, easy to arrive at this in the following manner:-Standardize 10 c.c. of the alcoholic solution of cream of tartar; these lo c.c. ordinarily require from 5 to 7 drops of normal soda solution. As the bitartrate of soda is soluble in the alcoholic liquid, a sufficient quantity of this salt should be added so long as the acidity of the liquid increases, that is to say, so long as it requires to saturate the 1o c.c.

72

On some Naphthalic Derivatives.

of alcoholic liquid, more of the normal soda solution than would previously have been required before the employment of the alcoholic liquid. When the Io c.c. require 20 to 30 drops of normal soda solution, it may be filtered, washed, and estimated as before, taking care to continue the washings until the strength of the alcoholic solution has returned to its original standard. As in all methods of analysis by standard solutions, a certain amount of skill is required to arrive at accurate results; but this plan seems to be capable of extreme accuracy, as the following experiments will show:One gramme of chloride of potassium was dissolved

and treated with bitartrate of soda:

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fix oxygen on an organic matter without greatly altering the molecule. Thus I have been able, by the action of this reagent, to produce phenoic acid (Runge's rosolic acid) at will, by heating phenic acid in contact with the air, and at a fixed temperature.

By applying this process, on this occasion not to a body having a certain chemical affinity, but to an agent entirely dissimilar-nitronaphthaline,-I have obtained a new product, which appears to me from its composition to be as interesting from its derivatives as from the uses to which it may be susceptible. Mononitrated naphthaline, like naphthaline, offers great resistance to ordinary oxidising agents. Under the influence of such reagents, a portion of the substance is generally destroyed, without the formation of any new product; sometimes the

In two grammes of the same substance there were molecular group is altered by the elimination of a certain obtained:

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One gramme of sulphate of potash treated in the same manner gave a result of 1010 grammes.

It is true that a portion of the alcoholic solution remains in the filter-paper; but, according to an experiment of the author's, on a paper of 115 millimètres, he found that it retained at most only one-sixth of solution.

This method may also be applied to the estimation of potash by weighing. It is only necessary to precipitate the potash with chloride of platinum, and to weigh the resulting chloroplatinate as in the ordinary process. There is an advantage in this plan, in being able to precipitate the potash by chloride of platinum, not only when it is in the state of chlorate, but also when it is present in the form of sulphate.

To estimate the potash in acid solutions, recourse must be had to the formation of alum, or to the following method recently proposed by M. Maumené.-Annalen der Chemie und Pharmacie, cxix, 123.

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can be used, like alum, to condense the potash in an alkaline mixture.

The bases are converted into neutral sulphates, the mixed salts dissolved, the sulphate of copper is added, and the mixture left to evaporate spontaneously. Fifteen days are required for the crystalline deposit to be complete; it is then washed, dried in the air, and weighed.

M. Barreswil remarks upon this (Répertoire de Chimie, 1861, p. 367) that this enormous time might undoubtedly be considerably abridged by precipitating the salt with alcohol, by effecting its crystallisation in concentrated liquids, or by many other plans.

On some Naphthalic Derivatives, by M. L. DUSART. SOME years ago I showed how potash-lime might be employed as an oxidising agent when the object is to

quantity of carbon, and the naphthalic type disappears. Direct oxidation, simply fixing the oxygen, has not yet been effected. However, it may easily be produced, at not very high temperature, by the above-mentioned reagents, the energy of which is relatively very feeble.

To this end I mix one part of nitronaphthaline, one part of caustic potass, dissolved in as little water as possible, and two parts of slaked lime; if too much water has not been added to the potass, the mass is pulverulent. I introduce it into a tubulated retort heated in an oil-bath to a mean temperature of 140°, and pass into it a slow current of oxygen or of atmospheric air. The gas is slowly absorbed, the mixture takes a yellow colour, which deepens as the operation proceeds. In about ten or twelve hours the oxidation is complete, and almost all the nitronaphthaline oxidised.

I am persuaded that the presence of air or oxygen is indispensable to the reaction. I have failed to produce oxidation by replacing the potash with soda; the lime also appears to be of especial service, for an inert matter, sand, for instance, cannot be substituted for it.

Taken from the retort, the mixture yields to water a salt of potash of a reddish yellow colour, possessing considerable colouring power. Acids added in slight excess to the solution change it into a thick magma formed of a beautiful yellow body, which, on being washed in distilled water, becomes almost perfectly pure.

This new body, which I will call nitroxynaphthalic acid, preserves, when dry, all its brightness. Its taste, at first fresh, becomes bitter; it is inodorous, but in a pulverulent state it excites the nasal mucous membrane. It melts towards 100°, and is not volatile; it dissolves in ordinary water, alcohol, pyroligneous acid, and acetic acid. In the latter it crystallises, by cooling, into beautiful golden-yellow needles.

It acts as a feeble acid, and, with alkalies, forms deeply-coloured, very soluble, and crystallisable sults, which yield, by double decomposition with metallic salts, variously coloured precipitates. Combined with bisulphite of soda, it forms a colourless salt, crystallising in fine needles; nitric acid attacks it with energy, forms oxalic acid, and at the same time a reddish resin, which by prolonged action is transformed into phthalic acid.

Contact with sulphuric acid heats it, developing sulphurous acid.

Energetic reducing agents transform it into a new substance, oxinaphthylamine.

The analysis of nitroxynaphthaline acid purified by crystallisation, and the estimation of its salts of baryta, lead, and copper, have led me to represent it by the following formula:

CH (NO) O.NO,

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