NEWS

monii also finds a place in the American work, and, considering the variable quality of scammony, this preparation is perhaps the most reliable form in which the medicine can be exhibited. It is directed to be prepared from commercial scammony, and not from the root. The scammony is exhausted by successive treatments with boiling alcohol; the mixed tinctures are then concentrated, and the resin precipitated by means of water.

The form given for the preparation of Spiritus etheris nitrosi may be recommended as an improvement on that given by the London College in 1851. Careful directions are given for the preparation of a strong alcoholic solution of hyponitrous ether, which is then rectified with a small proportion of carbonate of potash, and afterwards diluted by the addition of more alcohol. The directions, if care. fully followed, will probably give a preparation of pretty uniform strength. It is said to have the sp. gr. 837, and to contain from 4'3 to 50 per cent. of its peculiar ether. It is also directed to be preserved in well-stoppered halfpint bottles, and protected from the light.

Spiritus ammonia aromaticus is to be made in the way about to be introduced into our own Pharmacopeia. Carbonate of ammonia is dissolved in water with some liquor ammoniæ, the essential oils are dissolved in alcohol, and the two solutions are mixed together. This of course will give a preparation of definite strength and density. Some of the syrups are very useful and elegant preparations. Among them we notice a Syrupus rhei aromaticus, which must be a nice form for the administration of the medicine to children.

It is made as follows:

"Take of rhubarb in moderately fine powder, two troyounces and a-half; cloves, in moderately fine powder; cinnamon, in fine powder, each half a troyounce; nutmeg, in moderately fine powder, one hundred and twenty grains; syrup, six pints; diluted alcohol, a sufficient quantity. Mix the powders, and having moistened the mixture with two fluidounces of diluted alcohol, introduce it into a conical percolator, and pour diluted alcohol until a pint of tincture has passed. Add this to the syrup previously heated, and mix them thoroughly." "Syrup," we should add, is thirty-six troy ounces of sugar dissolved in water to make two pints, twelve fluid ounces, or, by weight, fifty-five troyounces.

Syrupus scillæ compositus is no doubt a very useful cough medicine, and may be of some interest to our readers at this period of the year, so we insert the formula in another place. In estimating the dose, they must remember that the American pint consists of sixteen ounces, and consequently each ounce of the syrup will contain one grain of tartar emetic.

Among the Tinctures we do not find much to remark upon. Tinctura ferri chloridi is here directed to be prepared by dissolving iron wire in hydrochloric acid, the solution being peroxidised by means of nitric acid; the spirit is afterwards added to the cold liquid.

A novelty to us is a Tinctura opii deodorata. In this preparation a fluid extract of opium is first made, and this is treated with ether. The ethereal solution which separates is rejected, and the remaining extract is again dissolved in water, filtered, and then mixed with the alcohol. The advantages of this preparation, if it have any, are unknown to us.

Among the Trochisci, we find a recipe for Trochisci cubeba, which is no doubt a useful and not disagreeable form of dragée. We shall quote the formula elsewhere.

The ointments and wines offer nothing for notice. The list of preparations concludes with those of zinc, and among them we find directions given for making acetate of zinc, by keeping a solution of acetate of lead in contact with metallic zinc, which, we may state, is by no means a satisfactory way of making a pure salt of zinc.

The last feature of the work we shall call attention to is the carefully compiled index, in which the "names are

so marked for the quantity of the syllables, that it may serve as a pronouncing vocabulary of the Materia Medica." Here the young pharmaceutist may see how to pronounce "Cre'ta" and "Ichthyocol'la;" and the older one who meets with the word for the first time need be in no difficulty about the pronunciation of “Cim'Içif'ăga."

NOTICES OF PATENTS.

Grants of Provisional Protection for Six Months. 2855. Lauchlan Mackirdy, Greenock, Renfrewshire, "Improvements in saturating, washing, and cleansing charcoal and other matters, applicable also to the separation of syrups from sugar.'

"

2875. Richard Archibald Brooman, Fleet Street, London, "Improvements in the manufacture of salt, and in boilers to be fed by salt water."-A communication from Charles Louis Edouard Lequin, Nancy, France.-Petitions recorded November 16, 1863.

2383. John Bailey, Salford, George William Blake, Manchester, and William Henry Bailey, Salford, Lancashire, "Improvements in barometers, gas regulators, and other apparatuses for regulating and indicating the flow and pressure of liquids and fluids." Petition recorded September 28, 1863.

2812. Andrew Craig, Rock Ferry, Birkenhead, Cheshire, "Improvements in distilling hydrocarbons from coal, shale, and other bituminous substances, and in apparatus employed for that purpose.'

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2839. James Medway and Samuel Joyce, Owen's Row, London, “ Improvements in the manufacture of starches by the introduction of colouring-matters."

2852. William Edward Newton, Chancery Lane, London," Improvements in the treatment or manufacture of wrought and cast iron and steel." A communication from Marc Antoine Augustin Gaudin, Rue St. Sebastien, Paris.

2864. Charles Pengelly, Bodmin, Cornwall, "Improvements in mechanism or apparatus for reducing or pulverising ores and other substances required to be reduced or pulverised."

2866. Gilbert Thonger, Birmingham, "Improved modes of preventing accidents arising from the sale or use of poisons."

2886. William Mattieu Williams, Oak Alyn, near Wrexham, Denbighshire, "Improvements in apparatus for the distillation of coal and peat, and such other substances as are or may be used for the manufacture of solid and liquid volatile hydrocarbons, or for the manufacture of the said hydrocarbons and coke."

2888. William Wigfall and Gottlieb Jolly, Sheffield, "An improved explosive compound to be used in the manufacture of cartridges, and an improved mode of manufacturing cartridges there with."

2894. Heinrich Hirzel, Terminus Hotel, London Bridge, Southwark, Surrey, "Improvements in the manufacture of colouring-matters suitable for dyeing and printing." Petitions recorded November 18, 1863.

2739. Richard Smith, Glasgow, Lanarkshire, N.B., "Improvements in preparing or obtaining colouring matters."-Petition recorded November 5, 1863. 2903. John Kirkham, Euston Road, London, "Improvements in the treatment of certain ores of iron."

2912. George Rait, Canal Bridge, Kingsland Road, and John Winsborrow, Castle Terrace, Pownal Road, Dalston, Middlesex, "Improvements in the construction of dry gas meters, and in the means or apparatus employed therein."

2931. Ferrar Fenton, Camberwell, Surrey, "Improvements in the treatment of vegetable fibres for the production of paper pulp or half stuff therefrom."

2951. Davis Wilson Rea, Upper Thames Street, London, "Improvements in preserving animal and vegetable substances."

CHEMICAL NEWS, } Jan. 16, 1864.

SCIENTIFIC AND ANALYTICAL

CHEMISTRY.

On the Separation of Stannic and Tungstic Acids, by C. RAMMELsberg.'

ACCORDING to H. Rose,t these acids may be separated by heating them in a stream of hydrogen. When the reduction is attempted in a porcelain crucible, a loss is always experienced, arising from the oxygen of the stannic acid, which is reduced to metal, and a third of the oxygen of the tungstic acid, which changes to tungstic oxide. By boiling in hydrochloric acid, the tin is dissolved, and can be precipitated by sulphuretted hydrogen, while the tungstic oxide is reconverted into tungstic acid by ignition in the air.

After analysing the compound of stannic and tungstic acid with iron and manganous oxide, described in the memoir mentioned below, I was induced to investigate this method, and first of all employed weighed quantities of the two acids.

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16.23; after the second, 20'86; after the third, 21-32. The last number is somewhat higher than the calculation requires, probably in consequence of the volatilisation of some of the tin. In this case the reduction was complete. The grey pulverulent mass contained white, malleable granules of tin, gave a colourless solution with hydrochloric acid, and left a black residue, which, ignited in the air, gave o778 of yellow tungstic acid, answering to 58 78 per cent. (Loss 082 per cent.)

III. 2212 of stannic acid and 2116 of tungstic acid lost, after several hours' strong ignition, o'88 = 20:33 per cent..

The mixture contained-

Stannic acid
Tungstic acid

In this instance, therefore, the reduction was almost complete.

100 parts of the mixture employed contained

100'00 20'916 11.389 If, therefore, the stannic acid was reduced to metal, and the tungstic acid to oxide, the loss should amount to 1139. Instead of this, however, the loss after the first heating amounted to 12.50 per cent.; after the second, 15.84 per cent.; after the third, 18.31 per cent. Thus, at the commencement, a portion of metallic tungsten was produced, the proportion of which naturally increased afterwards.

The residue ought to have given with hydrochloric acid only a colourless solution of chloride of zinc; but, instead of this, it gave first a blue and then a brown solution, while a part remained undissolved, which, by heating in the air, formed tungstic acid. The brown solution was filtered, but, after dilution, it became decolorised, and deposited yellow tungstic acid.

It appears, therefore, that it is difficult to conduct the operation so as to ensure the reduction of the tungstic acid only as far as the oxide WO2, and quite as difficult to separate the same from metallic tin by hydrochloric acid. II. To ascertain whether the strong heat of a gas lamp would also effect a complete reduction of tungstic acid, 1222 of stannic acid and 1803 of tungstic acid were strongly ignited in hydrogen gas. The loss of weight after the first ignition was 0'491; after the second, 0.631; and after the third, o'645.

100 parts of the mixture contained

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Rose, who has shown that stannic acid, when ignited with sal-ammoniac, is completely volatilised, states also that under the same circumstances tungstic acid remains unchanged, but that, in the presence of alkalies, tungstic oxide, tungstenamid, and nitride of tungsten are formed. I have employed chloride of ammonium as a means of separating quantitatively the two pure acids, and have obtained satisfactory results.

As the conversion of stannic acid into volatile chloride of tin requires a long time, the treatment of the mixture with six or eight times its weight of sal-ammoniac must be repeated several times, until no further loss of weight is observed. Great care must be taken that the outside of the porcelain crucible and cover does not become overspread with stannic acid, which is formed afresh from the chloride and surrounding moisture. Hence the smaller crucible should be placed in a larger one similarly covered, and heated to tolerably high temperature. The residue of tungstic acid is soon coloured green, then blackish; when heated in the air it becomes yellow, and has a constant weight.

I. 06977 stannic acid and 0.7335 of tungstic acid gave a final residue of 0.7225, which, after ignition in the air, weighed 0.7255. The difference amounts to o'008; that is, instead of 5126 per cent., only 50'7 per cent. was obtained.

II. 0554 stannic acid and 1332 tungstic acid left behind 1337 of the latter; that is, instead of 70'62 per cent., I recovered 70.89 per cent.

I have employed this method for the separation of the two acids in the combination mentioned at the commencement of this paper.

On Solution, by BARNARD S. PROCTOR, Esq. WHILE experimenting in August, 1860, I had occasion to mix 4 drachms of commercial carbonate of potass (not bicarbonate) with 7 fluid drachms of strong liquor of ammonia, 880 sp. gr. I was surprised to find so deliquescent a salt settle to the bottom with little appearance of solution. It had simply become moist, and disengaged a little gaseous ammonia.

Op. cit., vol. i., p. 234.

less successful, though not less interesting, than I anticipated, for on the separation taking place the potass liquor was found deep blue, and the ammonia almost colourless.

It was conjectured that the presence of the spirit might prevent the intersolubility of the two solutions; and to ascertain whether or not this was the case, two measures of a saturated aqueous solution of carbonate of potass, and one measure of strong liquor of ammonia, were agitated together. As complete separation appeared to take place, the proportions were reversed-that is, two parts of the ammoniacal to one of the potass solutionbut with the same result. The proportion of the ammonia was gradually increased till it amounted to about thirty times the measure of the potass solution, at which point the potass liquor dissolved in the ammoniacal.

I then thought it interesting to know to what extent the ammoniacal liquor would dissolve in the carbonate of potass solution, for which purpose 180 minims of the latter solution were taken and ro minims of liquor of ammonia added, which readily dissolved. Further additions were then made, 10 minims at a time, at every fifth addition the solutions being allowed to stand for five minutes.

In this manner, 140 minims were added before permanent turbidness was produced, the last four additions having produced milkiness and partial separation at the point of contact of the two solutions, until they were shaken, when perfect solution was effected. A further addition of 10 minims gave a permanent turbidness, resulting in a separation of the fluid into two solutions, the bulk of the heavier being to that of the lighter as 210 to 110-that is, the potass solution had gained 30 minims and the ammoniacal liquor had lost 40, the separation of the two being as distinct as the separation of oil from water. On standing twenty-four hours, resolution appeared to be taking place, the line of contact being much less visible, and appearing like that of two intersoluble liquids, as proved to be the case, perfect solution taking place on agitating them. During the twenty-four hours, a small, heavy, crystalline precipitate had deposited, probably carbonate of potass.

Though the results I have indicated with solutions of carbonate of potass and ammonia are very remarkable, they are not so completely isolated as I at first thought. That two aqueous solutions should not be soluble in one another, or readily miscible in all proportions, is a fact which would be thought striking by most chemists at first sight; but, on closer attention, we find several well-known phenomena of a somewhat similar nature.

The solubility of ether and water, which I before noticed, is a case in point: both the heavier and the lighter portions may be regarded as aqueous solutions. Again, the familiar case of carbonate of potass being added to weak spirit, a dense aqueous solution is formed at the bottom, and the supernatent liquid may be regarded as an aqueous solution of alcohol.

I also find that a saturated solution of oxalate of potass is not a solvent of a saturated solution of potass soap; and this leads us to the fact made use of in the soap works, that a concentrated solution of caustic soda is not a solvent of curd soap; so we find links in the chain sufficient to connect these new observations with other chemical facts well known and usefully applied.

I have sought to multiply instances of this species of insolubility with the hope of deducing a law, but I have as yet only met with one other salt-the soluble silicate of soda-which is not intersoluble with the aqueous ammonia.

I thought to find some solution which would compare with ammonia in its action, but as yet have found none, unless, as I just now suggested, we look upon ordinary spirit as a solution of alcohol. I have found four other salts, whose saturated solutions settle in spirit, like the carbonate of potass, without mixing, namely, phosphate of potass, citrate of potass, citrate of ammonia, and silicate of soda. Besides these, solutions of various other salts, which are less deliquescent, settle in the spirit, more or less speedily give up their water, while the salt itself is deposited in crystals. In this respect, also, the spirit and the ammonia resemble each other. Of eleven solutions of very soluble salts which are caused to crystallise by being poured into spirit, four crystallised on being poured into ammonia, namely, carbonate of soda, sulphate of soda, Rochelle salt, and chromate of potash.

With the desire of making the separation of the two solutions more visible, I purposed colouring the ammonia with sulphate of copper; but here again I met with unexpected results, for the immersion of a crystal of the sulphate scarcely tinted the ammonia; the crystal itself becoming coated with a dark blue crust.

A small quantity of a saturated solution of sulphate of copper was then added to the ammonia; a blue precipitate was produced, which was, contrary to expectation, almost insoluble in the excess of ammonia present. A small crystal of nitrate of copper was found to dissolve freely in the ammonia, affording the deep blue liquor which was desired, and with this solution I hoped to render more conspicuous the separation of the potass

and standing for several hours the solution remained fluid and separate from the spirit, until, a small crystal having been dropped in, rapid crystallisation took place, the water of the solution then, of course, uniting with the spirit.

On the Supposed Nature of Air prior to the Discovery of Oxygen, by GEORGE F. RODWELL, F.C.S. (Continued from page 16.)

Some of the more important of the forty-three experiments detailed in the treatise we are considering, are given below:

In the first experiment Boyle explains by what means the receiver of his air-pump is exhausted, and he affirms

Jan. 16, 1864.

that most of the experiments which he is about to relate, may be explained by bearing in mind the fact, "that there is a spring or elastical power in the air we live in." He compares the air to a fleece of wool, or a dry sponge, or says we may admit Des Cartes' theory, that the air is made up of innumerable flexible particles, which are so moved about by the motion of the celestial matter in which they swim, that each particle keeps those around it at a distance. Boyle prefers to believe that the air itself is elastic, rather than to admit Des Cartes' theory.

The height of the atmosphere, according to Kepler, is only eight miles, but Ricciolo makes it probable that it extends to a height of fifty miles. Can we not, therefore, well imagine, writes Boyle, that the weight of a column of air of such a height will keep "the little springs" of the air bent, and that when that weight is removed they will straighten themselves.

Experiment 2. When a stoppered receiver was exhausted of air, great force was found to be necessary to remove the stopper.

From the length at which this experiment is detailed it would appear that Boyle had not heard of the Magdeburgh hemispheres, although they were invented several years previously.

Experiment 4. A half-blown bladder placed in the receiver became fully expanded on exhausting.

This experiment had been previously tried by Roberval, by introducing a nearly empty carp's bladder into the Torricellian vacuum.

Experiment 5. When the exhaustion was long continued the bladder burst; a partially-filled bladder also burst when held near a fire.

Experiment 6. In order to determine to what extent a known quantity of air could be made to expand, when pressure was removed from it, Boyle took a phial containing four or five drachms, tied an empty lamb's bladder over its mouth, and placed it in the air-pump receiver; exhaustion was continued until the bladder was fully expanded, and by comparing the capacities of the phial and bladder, the air was found to have expanded to nine times its original bulk.

This mode of experimenting was evidently borrowed from Bacon, who, in the 40th Aph. of Book 2 of the "Novum Organum," describes an experiment which he made in order to determine the space occupied by the vapour produced from a liquid occupying a known space; in other words, the ratio between the spaces occupied by a substance when in the liquid and gaseous states. This experiment, although it could only give most fallacious results, is well worthy of record, inasmuch as it was made at a time when experiments of any kind were rare, and quantitative experiments most rare.

27

converted into vapour was found, and the space it occupied being compared with the contents of the bladder, it was shown that the spirit of wine occupied in the state of vapour 100 times the bulk it possessed in the liquid form.

But we must return to Boyle's experiment on the expansion of air under diminished pressure. After making the experiment with the bladder and phial, he devised a far more accurate method, which was to place within the receiver a tube, closed at one end, to which a divided scale was attached, and the capacity of which was known. The tube was entirely filled with water, with the exception of the space occupied by a small quantity of air of known bulk, and its lower end was placed in a vessel of water. When pressure was removed, the air within the tube expanded and depressed the column of water, and the amount of expansion was shown by the scale. By this means it was found that air expanded to thirty-one times its bulk, but the tube was too short, and the air still continued to expand, when the experiment had to be stopped. He next made use of a tube three feet long, passed it air-tight through the cover of the receiver, and placed the phial of water, into which its open orifice dipped, within the receiver; a known quantity of air was now found to expand to 152 times its previous bulk; it is obvious, however, that the inaccuracy of the experiment increases with the length of the tube, because, when the exhaustion has proceeded to a certain extent, tho column of water will fall, not only on account of the expansion of the air above it, but also because its own weight can partially overcome the pressure of the rarefied air in the receiver.

Experiment 7. A small globe of very thin glass, filled with air, was placed in air-tight connexion with an exhausted receiver: on suddenly turning the stop-cock so as to open free communication with the receiver, the globe was not broken, probably, Boyle says, on account of its shape.

Experiment 8. The helmet of a glass alembic was fitted with a stop-cock, every other part being closed; the shank of the stop-cock was cemented into the upper orifice of the pump-barrel; on exhausting, the helmet was broken.

Experiment 9. A glass tube, open at both ends, was cemented firmly into the neck of a glass phial containing a small quantity of water, so that its lower end reached nearly to the bottom of the phial; the latter was placed in a small receiver, and the tube passed air-tight through the cover; on exhausting, the phial was burst, because, says Boyle, the inside of the phial bad to bear the whole weight of the atmosphere, and there was no corresponding pressure to counterbalance it on the outside. The thinnest glass vessel is not broken in the air, because both the inside and outside are equally pressed; in other words, it is submitted to no pressure at all.

Experiment 10. A lighted candle was placed in the

* Hero of Alexandria, who was acquainted with the elasticity of the air, compares it to horn shavings, or a sponge. See the first of these papers, CHEMICAL NEWS, vol. viii., p. 115.

Pascal, as we have seen in the previous paper, compared the air to wool, a favourite simile of Boyle's throughout this work, but whether taken from Pascal or not it is difficult to say. Pascal's treatise "On the Weight of the Mass of Air," was not published till 1663, but Boyle may have heard of the comparison from some one who had conversed with Pascal.

The phial burst with such violence that it cracked the air-pump receiver, a not unfrequent occurrence, however, from other causes: aud, as receivers were difficult to procure, Boyle was in the habit of covering the cracks with cement, and afterwards with diachylon

plaster. The following is his account of the preparation of the cement :

nimbly ground with a pestle in a mortar, with a quantity (I know not how much precisely, not having the essays in this place) of scrapings of cheese, and a little fair water, no more than is just necessary to bring the mixture to a somewhat soft piste, which, when the ingredients are exquisitely incorporated, will have a strong and stincking smell. Then it must be immediately spread upon a linnen cloath of three or four fingers' breadth, and presently apply'd, lest it begin to harden. But if your Lordship had seen how we mended with it receivers, even for the most subtle Chymicall spirits, you would scarce nonder at the service it hath done in our Pneumaticall Glass."