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coloured the solution may be, on the mirror it appears perfectly colourless.

With the mirror it is quite easy to detect the presence of lime by means of ammonic oxalate in one drop of the Liverpool water, even in the cold. With baric chloride the sulphates make themselves very palpably visible; indeed, I think they might almost be estimated quantitatively in the undiluted water.

Royal Institution Laboratory, Liverpool,
April 3, 1879.

RELATIONS BETWEEN TEMPERATURE AND
VOLUME IN THE GENERATION OF OZONE,
WITH DESCRIPTION OF

A NEW FORM OF OZONATOR.

By ALBERT R. LEEDS, Ph.D.

THE methods usually employed to generate ozone, by means of the slow oxidation of phosphorus partly immersed in water, are quite unsatisfactory. Thus Miller (" Elements of Chemistry," 2nd ed., Part II., p. 23) directs that a stick of clean phosphorus, moistened with a few drops of water, should be placed in a bottle of atmospheric air. In an hour or two the production of ozone attains a maximum, when, if the phosphorus be not removed, the ozone disappears, owing to its combination with the phosphorus. Instead of a bottle a large glass balloon is preferably employed, which Arenat ("Lehr. der Anorgan. Chem.," p. 416) directs to be covered with a glass plate, and allowed to remain before using for twelve hours. Gorup-Besanez ("Anorgan. Chem.," p. 358) recommends, in addition to the foregoing, that the bottom should be maintained for several hours at a temperature of 16° to 20°. As means of studying, or even of exhibiting to a class, the properties of ozone, everyone who has used these and similar devices will probably have found them disappointing. At times a considerable evolution of ozone occurs, at others little or none. The causes of these variations will appear on examination of the experiments detailed later.

In a work published much earlier than the two last quoted, an apparatus is described and illustrated ("Leçons de Chimie," A. Riche, tome i., p. 106), which was a step in the right direction. The balloon was provided with an entrance and exit tube, the latter extending nearly to the bottom, so that a slow continuous current of air might be drawn through by means of an aspirator. The ozonised air was washed in the usual manner, and the liquids to be subjected to the action of ozone were placed in a second wash-bottle. This contrivance was adopted, a large bell-jar turned upside down and covered with a glass plate being substituted for the wash-bottle when it was desired to ozonise dyed goods, flowers, and similar large objects. The apparatus was further improved by using a bell-jar in place of the balloon. The bell was set in a dish containing a number of sticks of phosphorus, the water with which they were partly covered acting as a seal. The disagreeable operation of occasionally cleansing the phosphorus by scraping was obviated by immersing them before using in a mixture of potassium bichromate solution and sulphuric acid.

These improvements, however, were of small importance compared with that effected by substituting the bichromate mixture for the water in the generator itself. The scanty fitful evolution of ozone was replaced by a copious and constant supply. The disk was now replaced by a jar capable of holding a considerable amount of the bichromate solution, and by permitting a considerable change of level in the liquid the air could either be drawn through by aspiration or forced through by pressure. Instead of placing the phosphorus on the bottom the sticks were now supported on a glass disk, which dropped into a cell connected with a paraffined iron rod sliding up

and down through the cork at top. In another generator the cell was replaced by a brass stirrup electroplated with gold; but this had to be abandoned, the solution speedily eating away the metal.

A difficulty now arose from the danger of inflammation, resulting from the great energy of oxidation. This danger seemed largely due to irregular melting down of the phosphorus, ridges being formed which protruded too far above the liquid. This unequal action also greatly diminished the amount of surface which could be safely exposed. To obviate these difficulties watch-glasses were placed in a shallow tin dish, filled with water, sufficient fragments of phosphorus placed in each, and the temperature raised until by melting the phosphorus a number of rounded cakes of uniform size had been made. Six of these could be placed upon the stage at one time, and the stage adjusted so that each cake exposed about 9 c.m. of surface area. As the convexity of the exposed portions was small, the liquid by surface action was constantly drawn on it in thin streams, and not only kept the phosphorus wet, but always clean and in condition of maximum chemical activity.

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It was found, as will be seen by results stated below. that the air ozonised in one bell could have its ozone percentage notably increased, by passing through a second bell similar to the first, through a third, and so on. as the manipulation of three, or even two, bells connected with glass tubes was troublesome, it became necessary to arrange suitable machinery. The bells were therefore cemented into heavy brass caps. Through these caps and the paraffined cork beneath, connecting tubes of heavy glass were passed, and a sliding glass rod which terminated below in a horizontal circle. The latter carried a disk of sheet lead, with a slot permitting its easy removal. The caps were then screwed fast to a board, having a suitable opening down its middle to permit of passage of tubes, &c., and this again fastened to chains by which it might be readily raised or lowered. The frame is made Thermometers are of such height that the jars may be easily slipped from under the bells when desirable.* fastened into the side of each bell, their bulbs dipping just below the surface of the liquid.

It was evidently essential to convenient working of this apparatus to have a flexible connection between exit-tube and wash-bottle; but herein arose a very serious difficulty, india-rubber being destroyed. Through suggestion of Prof. Silliman, and by kindness of Mr. A. G. Day, the

* These ozonators are manufactured by S. Hawkridge, successor to Walls and Co., Stevens Institute of Technology.

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patentee, I became provided with a great variety of kerite tubing. Weighed samples of each kind were subjected to equal amounts of ozone for equal intervals, their changes and the products of decompositon noted. Without detailing these experiments, suffice it to say that the specimens which gained most in weight underwent greatest decomposition, some indeed crumbling to pieces, while others which gained none also did not change in appearance or physical characters. Of these the most satisfactory was selected, and from it as a guide Mr. Day manufactured the ozone-resisting kerite which is now used in connection with the ozonator.

{CHEMICAL NEW

April 10, 1879.

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A third series of experiments was instituted to determine whether the air which had been ozonised in this manner could receive an increment of ozone by being again subjected to the influence of phosphorus in a second bell-jar. The liquid contained, to each litre of saturated solution of bichromate, 250 c.c. H2SO4. Temp. Amount of Air.

2.0 litres

Time.

12 minutes

Hyposulphite.

I'20 C.C.

The improvements effected in the ozone-generating apparatus were due, as has been said above, to a series of quantitative trials, the result of each set of experiments suggesting modifications in the next series. In the first place phosphorus was used with water alone, one bell only being employed. The ozonised air was washed, and afterwards drawn through two Peligot tubes containing a 10 per cent solution of potassium iodide. The second tube was added as a guard, but in practice is unnecessary, complete absorption occurring in the first. The liberated iodine, after acidifying with sulphuric (free from nitrous) acid, was titrated with sodium hyposulphite. In each experiment 9 litres of air were drawn over. It soon became evident that widely differing results were obtained at different temperatures, the percentage of ozone falling off with decrease of temperature to zero. Starting from III. Ozone from Phosphorus in Bichromate (Two Bells). this point it appeared to increase, according to some unknown law, to a maximum, and then decrease again with further increase of temperature, until the point of inflammation of the phosphorus was obtained. The volumeratio is given in terms of o'005 V. p.c., taken at a convenient unit :

I. Ozone from Phosphorus in Water,

13°

19

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For convenience of comparison between these experiments and others, in which oxygen, not air, has been ozonised, columns 6 and 7 have been added-the former giving the percentage by weight of ozone in the oxygen passed over, disregarding the nitrogen; the latter, the percentage by volume. It will be seen that the maximum was attained at about 25°, when the air contained 1 m.grm. ozone in the litre, or about c.c. In the second series of experiments the water was replaced by a solution, containing to the litre of saturated solution potassium bichromate, 150 c.c. H2SO4. In each experiment 8 litres air were drawn over. The results were as follows::

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It will be seen that the air ozonised in two bells likewise contains a maximum percentage at 24°, but this maximum is 25 per cent higher than the corresponding amount obtained with one bell; and in general the percentage obtained by two bells is 25 per cent greater than that with one bell at any given temperature.

Before proceeding further it appeared advisable to determine whether some other liquid might be substituted for the bichromate with advantage. Alkaline liquids seemed inapplicable, owing to the danger of formation of alkaline hyposulphites and the evolution of hydrogen phosphide. Of the acids sulphuric appeared the most suitable, although even this was attended with the disadvantage of the probable formation of some sulphurous anhydride at the same time. Mixtures of potassium permanganate and similar salts with dilute acid have not as yet bee tried. The permanganate would have the disadvantage of being expensive, and even when sold as chemically pure is usually contaminated with much potassium chlorate. The results obtained with a bath containing 250 c.c. H2SO4 to the litre of water were as follows, 2 litres of air aspirated in each experiment, the interval varying from twelve to twenty-five minutes:

Temperature 25° Sodium hyposulphite 160 c.c.

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From which it would appear that at a temperature of about 6° no ozone is given off, and from this point the percentage rises until the temperature attains about 24°. the percentage falling off quite evenly on both sides of the maximum. The maximum production was 1.86 m.grm. per litre air, corresponding to o'87 c.c.

These low results made it appear probable that the phosstand for some time in the bichromate mixture, and the phorus had become oxidised. It was therefore allowed to experiment repeated :

Temperature 27° Sodium hyposulphite 1'70 c.c, Although even this amount was not so high as that previously obtained under similar circumstances, at the same

temperature, when the bichromate was employed, yet it confirmed the justness of the above supposition, and caused the use of the acid alone as a bath to be definitely abandoned. In the following table the trials are given in the order as made, with the view of showing the gradual deterioration. The abnormally high result obtained for the first 26° was due to the phosphorus having been kept for an unusual length of time in contact with the air in the bells, before aspiration was begun.

those read from the thermometers in the three bells, a reading being taken from each at the beginning, middle, and end of every experiment, and the average result stated. After the apparatus and bath had arrived at the temperature desired, the stages were raised by one motion of the crank to the height proper to expose a uniform surface of phosphorus; 8 litres of air aspirated, and then 1, 2, or more litres, the ozonised air in the latter case being titrated by solution of potassium iodide. All the figures obtained are given, although they are not so uniformly progressive as was hoped for-a result due, perhaps, in part to the difficulty of completely changing the atmosphere in three 6-litre bells by a slow current of air, without an expendiV. p.c. of O. ture of an amount of time which other duties would not permit. 0'5011 0'340 O'9154 0.616 Temperature. Amount of Air. O'3347 O'225 0'4104 0'276 0'4259 0.287 0 5365

IV. Ozone from Phosphorus in Sulphuric Acid. (Two Bells.)

M.grms.
Temp. per Litre, Wt. p.c.
Air.

C.c. per
Litre.

25°

1'512

0.1169 0'708

Vol. Ratio. 14.2

Wt. p.c.
of O.

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ON SOME NEW FORMS OF APPARATUS.
By M. BENJAMIN, Ph.B.

A NEW form of constant level water-bath has recently been devised, which is so simple that I will call public

attention to it.

FIG. I.

PROCEEDINGS OF SOCIETIES.

CHEMICAL SOCIETY.

Thursday, April 3, 1879.

Dr. WARREN DE LA RUE, President, in the Chair.

THE minutes of the Anniversary and last Ordinary Meetings were read and confirmed.

The following certificates were read for the first time :J. Fletcher, W. J. Bayne.

The PRESIDENT then called on Dr. TILDEN to read a paper on "Terpin and Terpinol." This communication is a continuation of a previous paper (Chem. Soc. Fourn., June, 1878). Crystallised Terpin.-The liquid left after the deposition of the crystals has gone on some time contains terpinol and a nitrate, or the compound of terpinol with a nitrate, for after washing thoroughly with water and Much inconvenience has been experienced by chemists, distilling in steam the yellowish oil obtained gives ammowho, having occasion to leave their laboratories for a nia by the action of reducing agents, and when heated while, on returning find that their baths have become dry, evolves nitrous fumes. Attempts to substitute sulphuric, and possibly that the contents of the vessel over the bath acetic, and hydrochloric acids for nitric acid failed. The may have been transferred to the floor by the increased terpentin hydrate, CroH180 of Deville, seems to be nothing heat, and the analysis is thus destroyed. The present but terpinol. The author has obtained crystals of terpin ingenious device is so constructed as to obviate any such hydrate from essence of lemon, identical in form with difficulty. Its mode of working is simple, and is as those obtained from American and French turpentine: he follows:-A large vessel (a common glass bottle will has not prepared similar crystals from the terpene of answer) is filled with water, and placed on a shelf or sup-orange oil. Terpinol.-The author has taken the vapour port above the bath. The water flows through a piece of density of this substance, and from it concludes that its rubber hose to the larger glass tube on the right of the formula is CroH180. The alcoholic solution of terpinol dissolves I atom of sodium from sodium-amalgam, forming a white pasty substance, from which terpinol is regenerated by the action of water. No ether was obtained by the action of acetic acid. Hydrochloric acid gas is absorbed by terpinol, and the mixture at first turns purple, but finally is converted into a mass of colourless crystals (C10H18C12), melting at 48°. From various considerations the author considers the character of terpinol to be that of an alcohol rather than that of a ketone like pinacolin. Sulphuric acid when heated with terpinol produced dehydration with partial polymerisation of the resulting hydrocarbon, which is apparently identical with terpilene. anequal volume of sulphuric acid, diluted with half its When, however, terpinol is mixed gradually with nearly bulk of water, but little heat is evolved, and no separation of the liquids takes place: on adding 3 or 4 volumes of lised mass of terpin, mixed with only a small quantity of water the whole solidiñes in a few minutes into a crystalliquid hydrocarbon. Oil of lemon, cajeput oil, oil of identical with terpinol or mere physical modifications of coriander and citronella apparently contain bodies either that substance. Resin spirit does not apparently contain terpinol.

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figure; running down this tube, it passes to the bath through the copper tube connected with the bottom of the bath. Within this glass tube is a smaller one, which is on an exact level with the top of the water-bath, through which any excess of water passes away and falls to the ground. The flow of water from the bottle can easily be regulated by means of an ordinary pinch-cock.

This water-bath is finding considerable use among students in the different laboratories, who are liable to be FIG. 2.

called away to lectures, so that much of their time, otherwise lost, is saved by the use of this appliance.

The second engraving represents an improved form of burette clamp, which consists of two arms, one of which

Dr. ARMSTRONG thought that the reactions of terpinol pointed to a resemblance in constitution to pinacolin rather than to an alcohol, and suggested that terpin, terpinol, &c., should have a rational name expressing to some extent their constitution.

Dr. TILDEN, in reply, said that he should be reluctant to change the name until homologues were discovered, as it had been suggested by Berzelius: on the whole he adhered to his statement in the paper, that the behaviour of terpinol resembled that of a secondary or tertiary alcohol.

NEWS

Mr. G. ATTWOOD then read a paper " On a Gold Nugget from South America." In the State of Guayana, Venezuela, a large area of alluvial soil has lately been found to contain gold, and nuggets up to 25 ounces have been discovered within 3 feet of the surface. Numerous goldbearing quartz veins are found in the neighbouring hills. Quite one-half of these nuggets are covered with a dark brown substance, resembling a silicate of iron. Such a nugget was treated with hydrochloric acid (its weight diminished, after treatment with HCI and NaO, from 304 7 grains to 284 33 grains). The solution containedSilica, o'12 gr.; ferric oxide, 888; lime, o15; magnesia, o'08. The nugget was then treated with caustic soda, and again with HCl. The solution containedSilica, 466 grs.; ferric oxide, 460; lime, o 21. During this process much gold in a finely divided state became detached, and after the treatment the nugget was partly covered with a coating of finely divided gold, of a dull colour. The nugget contained 94'54 per cent of gold. The gold from the quartz veins contains 87.9 per cent gold. From these experiments the author concludes that gold nuggets gradually increase in size, owing to the accumulation of fresh particles of finely precipitated gold. Specimens of these nuggets showing the dark glazed coating were exhibited, including one weighing over 14 ounces.

Mr. W. W. FISHER then comniunicated a paper "On Lead Tetrachloride." The existence of this compound has been for many years assumed on theoretical grounds, but direct experimental evidence has not been hitherto obtained to establish its composition. The author has therefore followed a plan similar to that already used by him to prove the existence of manganese tetrachloride. Lead dioxide dissolves in moderately strong hydrochloric acid, forming a yellow solution smelling strongly of chlorine. This yellow solution gives a precipitate of brown hydrated peroxide of lead when treated with solutions of the fixed alkalies or alkaline carbonate, &c. The addition of water causes a similar precipitation if an excess of hydrochloric acid be avoided, and the liquid carefully saturated with the dioxide. The author gives his method of analysis: he concludes that the yellow solution contains a compound of lead with chlorine, containing 1 atom of lead to 4 of chlorine. If red-lead be substituted for the lead dioxide a similar yellow solution is obtained; it can also be prepared by the action of chlorine on lead chloride suspended in dilute hydrochloric acid or solution of a chloride. If water alone be used, lead dioxide is deposited simultaneously with the formation of the yellow solution. From his experiments the author concludes that lead tetrachloride is unstable in the presence of water alone, but may exist as a double salt in the presence of other chlorides. In conclusion, the author suggests the use of chlorine or bromine in the presence of sodium acetate as a means of quantitatively determining lead by precipitation as peroxide, in cases where the use of sulphuric acid | is unadvisable, and gives results obtained: by thus precipitating a solution of lead acetate (in the presence of sodium acetate) as peroxide, igniting the latter to protoxide, and weighing 54'71 and 54.67 per cent Pb were obtained, theory indicating 54.67.

The PRESIDENT remarked on the importance of the suggestion as to the use of Br and Cl for precipitating lead from solution, as in many cases sulphuric acid did not completely precipitate lead.

After a short discussion, in which Drs. Wright and Tilden and Messrs. Hartley and Neison took part, Mr. Fisher replied.

The SECRETARY then read a short note by Messrs. DALE and SCHORLEMMER, "On the Transformation of Aurin into Trimethyl-pararosanilin." This transformation was effected by the action of an aqueous solution of methylamin, at 125°, on aurin, a purple colour being formed possessing all the properties of a trimethyl-rosanilin. Intermediate compounds, soluble in alkalies, were simultaneously produced, and are at present under investigation,

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The next paper was "On the Solution of Aluminium Hydrate by Ammonia, and a Physical Isomeride of Alumina," by C. F. CROSS. The author has made quantitative experiments with solutions of ammonia of various strengths. His results indicate that ammonia dissolves to a certain extent the hydrated oxide at the moment of precipitation: the quantity dissolved bears no relation to the strength of the ammonia, but is considerably lessened by the presence of ammoniacal salts. The author has also examined the precipitate obtained by boiling the ammoniacal solution of the oxide: it is granular, is slowly dissolved by boiling hydrochloric acid; dried at 100° it is an opaque white powder; on igniting it undergoes no apparent change, but in the anhydrous condition it is extremely hygroscopic, absorbing 35'70 of water; its composition is Al2O3.

The last communication was entitled "Researches in Dyeing (Part II., Note on the Emission of ColouringMatter), by Dr. MILLS and Mr. CAMPBELL. The experiments were made as described in Part I. (Chem. Soc. Journ., 1879). The colour selected was well-crystallised Nicholson's blue. The vats contained o 2780 grm. of pure silk ribbon, and o'o100 grm. of blue in 400 c.c. of water; one contained in addition I grm. of HCl, and a third I grm. of NaCl. The most interesting result obtained by the authors is that the energy of combination between silk and the blue, when water or potassic chloride is used, is over-developed at first, and the excess of colouringmatter so taken up is gradually emitted by the silk during the third and fourth days; the addition of sodic chloride completely prevents this result. The authors also affirm that a real and uniform dyeing effect can always be obtained with silk and Nicholson's blue, the heat and souring used by dyers being unadvisable. The authors recommend the addition of common salt to the vat.

The PRESIDENT, in adjourning the meeting to April 17th, said that as so many candidates were awaiting election he hoped that Fellows of the Society would make every effort to be present on that date, so that a ballot might be taken.

The following papers were announced :-"On the Determination of Tartaric Acid in Lees and Inferior Argol, with some Remarks upon Filtration and Precipitation," by B. J. Grosjean. "On Conditions affecting the Equilibrium of certain Chemical Systems," by M. M. P. Muir.

CORRESPONDENCE.

ARSENICAL WALL PAPERS.

To the Editor of the Chemical News. SIR,-I have read and heard of a good many cases of reputed poisoning from arsenical wall papers, but have never till now met with a case myself. It would seem that some people are more susceptible than others. I have slept for months in a room the paper of which contained an enormous quantity of As without experiencing any ill-effects therefrom, although I could easily rub the colour off with my finger-but to my case.

A lady in this town complained of a peculiar feeling of constriction in her nose, accompanied by a "nasty smell," nausea, and loss of appetite, and was unable to discover the cause. The symptoms had been felt since sleeping in a certain room, which she had done for two months. Somebody, I believe, suggested arsenical paper. I examined the paper and found a very large quantity of As, more than I have ever found in any paper before. H2S gave at once a brilliant orange precipitate. Under the circumstances I could do no less than recommend that the paper should be removed, but I wanted her to try the experiment of sleeping in another room for a time to see if the symptoms disappeared, and then return again to see

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