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coloured the solution may be, on the mirror it appears, and down through the cork at top. In another generator perfectly colourless.

the cell was replaced by a brass stirrup electroplated with With the mirror it is quite easy to detect the presence gold; but this had to be abandoned, the solution speedily of lime by means of ammonic oxalate in one drop of the eating away the metal. Liverpool water, even in the cold. With baric chloride A difficulty now arose from the danger of inflammation, the sulphates make themselves very palpably visible; resulting from the great energy of oxidation. This danger indeed, I think they might almost be estimated quantita seemed largely due to irregular melting down of the tively in the undiluted water.

phosphorus, ridges being formed which protruded too far Royal Institution Laboratory, Liverpool,

above the liquid. This unequal action also greatly dimiApril 3, 1879.

nished 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 temperRELATIONS BETWEEN TEMPERATURE AND ature raised until by melting the phosphorus a number of VOLUME IN THE GENERATION OF OZONE,

rounded cakes of uniform size had been made. Six of WITH DESCRIPTION OF

these could be placed upon the stage at one time, and

the stage adjusted so that each cake exposed about g c.m. A NEW FORM OF OZONATOR.

of surface area. As the convexity of the exposed portions By ALBERT R. LEEDS, Ph.D.

was small, the liquid by surface action was constantly drawn on it in thin streams, and not only kept the phos

phorus wet, but always clean and in condition of maximum The methods usually employed to generate ozone, by means chemical activity. of the slow oxidation of phosphorus partly immersed in

Fig. 1. water, are quite unsatisfactory. Thus Miller (" Elements of Chemistry,” and 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 20o. 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," Å. 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 ! It was found, as will be seen by results stated below. be drawn through by means of an aspirator. The ozon. | that the air ozonised in one bell could have its ozone perised air was washed in the usual manner, and the liquids centage notably increased, by passing through a second to be subjected to the action of ozone were placed in a bell similar to the first, through a third, and so on. But second wash-bottle. This contrivance was adopted, a as the manipulation of three, or even two, bells connected large bell-jar turned upside down and covered with a glass with glass tubes was troublesome, it became necessary to plate being substituted for the wash-bottle when it was arrange suitable machinery. The bells were therefore desired to ozonise dyed goods, flowers, and similar large

| cemented into heavy brass caps. Through these caps and objects. The apparatus was further improved by using a

the paraffined cork beneath, connecting tubes of heavy bell-jar in place of the balloon. The bell was set in a glass were passed, and a sliding glass rod which termi. dish containing a number of sticks of phosphorus, the

nated below in a horizontal circle. The latter carried a water with which they were partly covered acting as a

disk of sheet lead, with a slot permitting its easy removal. seal. The disagreeable operation of occasionally cleansing The caps were then screwed fast to a board, having a the phosphorus by scraping was obviated by immersing suitable opening down its middle to permit of passage of them before using in a mixture of potassium bichromate tubes, &c., and this again fastened to chains by which it solution and sulphuric acid.

might be readily raised or lowered. The frame is made These improveinents, however, were of small importance of such height that the jars may be easily slipped from compared with that effected by substituting the bichromate

under the bells when desirable.* Thermometers are mixture for the water in the generator itself. The scanty

fastened into the side of each bell, their bulbs dipping fitful evolution of ozone was replaced by a copious and just below the surface of the liquid. constant supply. The disk was now replaced by a jar

It was evidently essential to convenient working of this capable of holding a considerable amount of the bi. apparatus to have a flexible connection between exit-tube chromate solution, and by permitting a considerable

and wash-bottle; but herein arose a very serious difficulty, change of level in the liquid'the air could either be drawn

india-rubber being destroyed. Through suggestion of through by aspiration or forced through by pressure.

Prof. Silliman, and by kindness of Mr. A. G. Day, the Instead of placing the phosphorus on the bottom the sticks were now supported on a glass disk, which dropped These ozonators are manufactured by S. H zwkridg”, successor to into a cell connected with a paraffined iron rod sliding up | Walls and Co., Stevens Institute of Technology.

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New Form of Ozonator.

CHEMICAL NEW, 1 April 10, 1879.


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patentee, I became provided with a great variety of kerite II. Ozone from Phosphorus in Bichromate. iubing. Weighed samples of each kind were subjected to

(One Bell Jar.) equal amounts of ozone for equal intervals, their changes

and the products of decompositon noted. Without de- | Temp. per Litre, Wt. p.c.

C.e. per Vol. Wt. p.c. V. p.c.

Litre. Ratio. of O. of O. tailing these experiments, suffice it to say that the

Air. specimens which gained most in weight underwent greatest 70° O‘089 O‘0069 0'042 08 O‘0298 0'020 decomposition, some indeed crumbling to pieces, while 135 0945 0'07300-441 8:8 0-3154 0'210 others which gained none also did not change in appear. | 20'0 1'505 0·1163 0*705 14'1 095011 0'336 ance or physical characters. Of these the most satisfactory 2105 1'580 0'1221 0.741 14.8 05270 0*353 was selected, and from it as a guide Mr. Day manufactured 24'0 .857 0:1438 0·870 174 06221 0415 the ozone-resisting kerite which is now used in con- | 3145 1590 0'1229 0*745 14'

9 05314 09355 nection with the ozonator. The improvements effected in the ozone-generating ap.

| A third series of experiments was instituted to deterparatus were due, as has been said above, to a series of mine whether the air which had been ozonised in this quantitative trials, the result of each set of experiments manner could receive an increment of ozone by being suggesting modifications in the next series. In the first again subjected to the influence of phosphorus in a second place phosphorus was used with water alone, one bell bell-jar. The liquid contained, to each litre of saturated only being employed. The ozonised air was washed, and solution of bichromate, 250 c.c. H2SO4. afterwards drawn through two Peligot tubes containing a

Temp. Amount of Air. Time. Hyposulphite. 10 per cent solution of potassium iodide. The second tube was added as a guard, but in practice is unnecessary,

2.0 litres

I'20 C.C. complete absorption occurring in the first. The liberated

12 minutes 2'00 iodine, after acidifying with sulphuric (free from nitrous)

20, acid, was titrated with sodium hyposulphite. In each


3'00 » experiment 9 litres of air were drawn over. It soon be.

351 20 minutes came evident that widely differing results were obtained

20 ,

2:60 , at different temperatures, the percentage of ozone falling

2-25 , off with decrease of temperature to zero. Starting from

III. Oxone from Phosphorus in Bichromate (Two Bells). this point it appeared to increase, according to some un. known law, to a maximum, and then decrease again with


Wt. p.c. C.c. per
Temp. per Litre.

Vol. Wt. p.c. V.D.c. further increase of temperature, until the point of inflam.


Litro. Ratio. of o. of O. mation of the phosphorus was obtained. The volume 13° 1.134 0-0877 08531 10-6 0-3789 09255 ratio is given in terms of o‘005 V. p.c., taken at a conve.

1.890 01460 0.885 1797 0:6307 09425 nient unit :

21 1'985 O‘1546 0'929 18.6 0.6696 0'446

23 1.890 Oʻ1460 0885 1767 0:6307 0°425 1. Ozone from Phosphorus in Water,

2'155 0'1701 I'oog 202 07344 0 489

24 2.457 0'1933 1'151 2340 08338 0*552 M.grm. Cic. per Vol. Wt. r.c. V. p.c

2.127 27

0'16430'996 199 Temp.

0*7098 0'478
per Litre, wt. p.c. Litre. Ratio. of o.

of 0.
- None

It will be seen that the air ozonised in two bells like1995 0 615 00478 0'290 5.8 O'2065 0'139

wise contains a maximum percentage at 24°, but this 25'0 0.882 0'0682 0:413

0'2946 0198

maximum is 25 per cent higher than the corresponding 25'0 1 050 0'0812 0494 99 0'3508

amount obtained with one bell; and in general the per

0237 3095 0°326 0·0252 0·153 3:1 0:1088 0'073

centage 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 deterFor convenience of comparison between these experi. mine whether some other liquid might be substituted for ments and others, in which oxygen, not air, has been the bichromate with advantage. Alkaline liquids seemed ozonised, columns 6 and 7 have been added--the former inapplicable, owing to the danger of formation of alkaline giving the percentage by weight of ozone in the oxygen hyposulphites and the evolution of hydrogen phosphide. passed over, disregarding the nitrogen ; the latter, the of the acids sulphuric appeared the most suitable, al. percentage by volume. It will be seen that the maximum though even this was attended with the disadvantage of was attained at about 25, when the air contained i m.grm. the probable formation of some sulphurous anhydride at ozone in the litre, or about $c.c. In the second series of the same time.' Mixtures of potassium permanganate experiments the water was replaced by a solution, con- and similar salts with dilute acid have not as yet bee taining to the litre of saturated solution potassium bi. I tried. The permanganate would have the disadvantage chromate, 150 c.c. H2SO4. In each experiment 8ļ litres of being expensive, and even when sold as chemically pure air were drawn over. The results were as follows:

is usually contaminated with much potassium chlorate.

The results obtained with a bath containing 250 c.c. Temperature.


H2SO4 to the litre of water were as follows, 2 litres of air


aspirated in each experiment, the interval varying from 7

twelve to twenty-five minutes :


Temperature 25° Sodium hyposulphite 1.60 с.c.

2'90 ,


I'06 , - 24

I 30 , 30-3145

1'35 , 31-32

These low results made it appear probable that the phos.

phorus had become oxidised. It was therefore allowed to From which it would appear that at a temperature of about 6° no ozone is given off, and from this point the

stand for some time in the bichromate mixture, and the percentage rises until the temperature attains about 24°.

experiment repeated :ihe percentage falling off quite evenly on both sides of

Temperature 27° Sorlium hyposulphite 1670 c.c, the maximum. The maximum production was 1.86 m.grm. Although even this amount was not so high as that preper litre air, corresponding to o:87 c.c.

| viously obtained under similar circumstances, at the same















April 10, 1879. 1 temperature, when the bichromate was employed, yet it, those read from the thermometers in the three bells, a confirmed the justness of the above supposition, and reading being taken from each at the beginning, middle, caused the use of the acid alone as a bath to be definitely and end of every experiment, and the average result stated. abandoned. In the following table the trials are given in After the apparatus and bath had arrived at the temperathe order as made, with the view of showing the gradual ture desired, the stages were raised by one motion of the deterioration. The abnormally high result obtained for crank to the height proper to expose a uniform surface of the first 26° was due to the phosphorus having been kept | phosphorus ; 8 litres of air aspirated, and then I, 2, or for an unusual length of time in contact with the air in more litres, the ozonised air in the latter case being titrated the bells, before aspiration was begun.

by solution of potassium iodide. All the figures obtained

are given, although they are not so uniformly progressive IV. Oxone from Phosphorus in Sulphuric Acid. as was hoped for—a result due, perhaps, in part to the (Two Bells.)

difficulty of completely changing the atmosphere in three M.grms. C.c. per Vol. Wt. p.c. V. p.c.

6-litre bells by a slow current of air, without an expendiTemp. per Litre, Wt. p.c.

Litre. Ratio. of 0 of o. ture of an amount of time which other duties would not 254 1'512 O‘1169 0'708 14'2 0:5011

permit. 2741 0'2119 I'283 2597 0.9154 0:616 Temperature. Amount of Air. Time. Hyposalphite per

Litre. 1'002 0'0775 0469 994 0'3347 0'225

6'3° 3 litres 15 minutes 0'033 c.c. I'229 0'0950 0'575 10'5 04104 0-276

20 )

0'033 10 26 10275 O'og86 0'597 11'9 0:4259 0'287

10 63

15 10

o'080 , 1.607 0'1242 0'752 15'0 0 5365 0°361



0'200 Another related query was, whether so concentrated a bath


0'225 10 was essential ? 'To settle this point a solution was made


0'215 11 containing, to each 1250 c.c. H20, 150 c.c. H2SO4 and


0.680, 25 grms. K2C2Oy. The determinations were purposely


0.600 , made at about the maximum temperature:


0*400 1 Temperature 26'5' Sodium hyposulphite 2.0ɔ c.c. 14.99

0.400 ,

2 26'5 ,

, »


16:11 V. Osone from Phosphorus in Dilute Bichromate. 16:11

0.680 i . (Two Bells.)

0.840 ,

M.grms. ..
Wt. p.c.

0.610 10 Temp. per Litre C.c. per Vol.

V. p.c.
Wt. p.c.


in Air.
Litre. Ratio. of O. of O. 20'0

I'150 26'5° 1.890 0°1460 0.885 1707

1'520 0:6307 00425 22078 26°5 2°060

I'320 0*1592 0.965 19:3 06868 0:461

22078 25'0

I'420 These results, although inferior to those obtained with the 26°11

I'300 more concentrated solution, were nevertheless so satis.' 26:11





0.660 16

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TEMPERATURES: fadory and constant that this mixture was adopted, and An inspection of the diagram shows that in every case during the subsequent work the results arrived at on in the maximum evolution of ozone was at or near 24° C., creasing the number of bells to two bad been so gratifying | or about 75° F. To obtain the best results in every case, that it was thought advisable to employ three, and to therefore, a copper tank in which the jars are placed has combine them in an arrangement which would permit been added to the apparatus as figured, so that by heating them to be easily handled, the form finally adopted being or cooling the water it contains the jars and apparatus that figured in the text. The temperatures given are can be always maintained at the proper temperature. .


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Some New Forms of Apparatus.


1 April 10, 1879. VI. Oxone from Phosphorus in Dilute Bichromate.. I is fixed, while the other is held in position by means of a (Three Bells.)

joint, and is controlled by a spring, so that it acts as a M.grms. Temp. per Litre

lever, and by pressure it may be opened to any desired Wt. c. C.c. per Vol. Wt. p.c. V. D.C. in Air.

Litre. Ratio of o. of O. | width. The end of the clamp is provided with rubber 6.3° 0.0624 0·0048 0'029 0.6 0'0280

cushions, so as to hold a glass burette, or perhaps a fun0'014

nel, which is placed between its arms. This clamp is 10:63 0'1512 O‘0116 0'071 14 0'0501 0'034 III 0:1890 0'0146 0'089

made to slide on the upright of a common retort-stand.

0'0631 0'043 11'21 0'3780 0'0292 0'177 3'5 O'1262 0'085

New York, March 20, 1879. 12'22 0'4160 0'0321 0195 39 0 1391 0093 13'33 1'2850 0'0993

12'o 0 4290 0·289 13'33 I'1340 0'0876 0'531 106 0'3784 0*255 14.99 097560 0'0587 Oʻ354 71 0'2536


0'170 15.88

0°7940 oʻ0618 0-372 74 O‘2678 0:179 16:11 1°2850 0'0993 0.602 12'0 0-4290 0.289 1790 1'5880 0'1229 0°745 14:9 05309 0'355

CHEMICAL SOCIETY. 1705 I'1530 O'0889 0'540 10 8 0'3840 0'259

Thursday, April 3, 1879. 20'0 2'1700 0:1677 1018 20-4 0*7245 0486 22.78 2.6840 O‘2075 1'257 251 0.8964 0:603 Dr. WARREN De La Rue, President, in the Chair. 25'0

0'2075 1'257 25.1 0.8964 0.603 26.11 2.4570 0'1902 1'151 230 0·8212 0552 The minutes of the Anniversary and last Ordinary Meet. 26'11 292680 0:1778 1062 212 097690 08510 ings were read and confirmed.

The following certificates were read for the first time :

J. Fletcher, W. J. Bayne. ON SOME NEW FORMS OF APPARATUS. The PRESIDENT then called on Dr. Tilden to read a

paper on Terpin and Terpinol.This communication By M. BENJAMIN, Ph.B.

is a continuation of a previous paper (Chem. Soc. Juurn.,

June, 1878). Crystallised Terpin.-The liquid left after A new form of constant level water-bath has recently

the deposition of the crystals has gone on some time been devised, which is so simple that I will call public

contains terpinol and a nitrate, or the compound of terpinol attention to it.

with a nitrate, for after washing thoroughly with water and Much inconvenience has heen experienced by chemists,

distilling in steam the yellowish oil obtained gives ammo. who, 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, C10H180 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 C10H180. The alcoholic solution of terpinol

dissolves i atom of sodium from sodium-amalgam, forming Fig. I.

a white pasty substance, from which terpinol is regenerated

by the action of water. No ether was obtained by the TO

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 dehy. dration with partial polymerisation of the resulting hydro

carbon, which is apparently identical with terpilene. figure; running down this tube, it passes to the bath

When, however, terpinol is mixed gradually with nearly through the copper tube connected with the bottom of the

anequal volume of sulphuric acid, diluted with half its bath. Within this glass tube is a smaller one, which is

bulk of water, but little heat is evolved, and no separation on an exact level with the top of the water-bath, through

of the liquids takes place : on adding 3 or 4 volumes of which any excess of water passes away and falls to the

water the whole solidines in a few minutes into a crystal. ground. The flow of water from the bottle can easily be

lised mass of terpin, mixed with only a small quantity of regulated by means of an ordinary pinch-cock.

liquid hydrocarbon. Oil of lemon, cajeput oil, oil of This water-bath is finding considerable use among stu

coriander and citronella apparently contain bodies either dents in the different laboratories, who are liable to be

identical with terpinol or mere physical modifications of

that substance. Resin spirit does not apparently contain Fig. 2.


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 called away to lectures, so that much of their time, other. to change the name until homologues were discovered, as wise lost, is saved by the use of this appliance.

| it had been suggested by Berzelius : on the whole he ad. The second engraving represents an improved form of hered to his statement in the paper, that the behaviour of burette clamp, which consists of two arms, one of which terpinol resembled that of a secondary or tertiary alcohol.




Mr. G. ATTWOOD then read a paper “ On a Gold Nugget i The next paper was “On the Solution of Aluminium from South America.” In the State of Guayana, Vene- Hydrate by Ammonia, and a Physical Isomeride of zuela, a large area of alluvial soil has lately been found Alumina,” by C. F. Cross. The author has made quan. to contain gold, and nuggets up to 25 ounces have been titative experiments with solutions of ammonia of various discovered within 3 feet of the surface. Numerous gold strengths. His results indicate that ammonia dissolves bearing quartz veins are found in the neighbouring hills. to a certain extent the hydrated oxide at the moment of Quite one-half of these nuggets are covered with a dark precipitation : the quantity dissolved bears no relation to brown substance, resembling a silicate of iron. Such a the strength of the ammonia, but is considerably lessened nugget was treated with hydrochloric acid (its weight by the presence of ammoniacal salts. The author has diminished, after treatment with HCl and NaO, from also examined the precipitate obtained by boiling the 30487 grains to 284:33 grains). The solution contained- ammoniacal solution of the oxide: it is granular, is Silica, o'12 gr. ; ferric oxide, 8:88; lime, 0:15; mag. slowly dissolved by boiling hydrochloric acid ; dried at nesia, oʻ08. The nugget was then treated with caustic 100° it is an opaque white powder ; on igniting it undersoda, and again with HCl. The solution contained- goes no apparent change, but in the anhydrous condition Silica, 4:66 grs.; ferric oxide, 4:60; lime, O21. During it is extremely hygroscopic, absorbing 35'70 of water ; its this process much gold in a finely divided state became composition is Alq02. detached, and after the treatment the nugget was partly. The last communication was entitled “ Researches in covered with a coating of finely divided gold, of a dull | Dyeing (Part II., Note on the Emission of Colouringcolour. The nugget contained 94:54 per cent of gold. / Matter), by Dr. Mills and Mr. Campbell. The experiThe gold from the quartz veins contains 87.9 per cent ments were made as described in Part 1. (Chem. Soc. gold. From these experiments the author concludes that Fourn., 1879). The colour selected was well-crystallised gold nuggets gradually increase in size, owing to the ac. Nicholson's blue. The vats contained 0-2780 grm. of pure cumulation of fresh particles of finely precipitated gold. silk ribbon, and o'0100 grm. of blue in 400 c.c. of water ; Specimens of these nuggets showing the dark glazed one contained in addition i grm. of HCI, and a third coating were exhibited, including one weighing over i grm, of NaCl. The most interesting result obtained by 14 ounces.

the authors is that the energy of combination between 'Mr. W. W. Fisher then comniunicated a paper " On silk and the blue, when water or potassic chloride is used, Lead Tetrachloride." The existence of this compound is over-developed at first, and the excess of colouringhas been for many years assumed on theoretical grounds, matter so taken up is gradually emitted by the silk during but direct experimental evidence has not been hitherto ob the third and fourth days; the addition of sodic chloride tained to establish its composition. The author has there completely prevents this result. The authors also affirm fore followed a plan similar to that already used by him to that a real and uniform dyeing effect can always be obprove the existence of manganese tetrachloride. Lead tained with silk and Nicholson's blue, the heat and souring dioxide dissolves in moderately strong hydrochloric acid, used by dyers being unadvisable. The authors recommend forming a yellow solution smelling strongly of chlorine. | the addition of common salt to the vat. This yellow solution gives a precipitate of brown hydrated The PRESIDENT, in adjourning the meeting to April i7th, peroxide of lead when treated with solutions of the fixed said that as so many candidates were awaiting election alkalies or alkaline carbonate, &c. The addition of water he hoped that Fellows of the Society would make every causes a similar precipitation if an excess of hydrochloric effort to be present on that date, so that a ballot might be acid be avoided, and the liquid carefully saturated with taken. the dioxide. The author gives his method of analysis : ! The following papers were announced :—“On the De. he concludes that the yellow solution contains a compound termination of Tartaric Acid in Lees and Inferior Argol, of lead with chlorine, containing i atom of lead to 4 of with some Remarks upon Filtration and Precipitation,” by chlorine. If red-lead be substituted for the lead dioxide B. J. Grosjean. “On Conditions affecting the Equilibrium a similar yellow solution is obtained; it can also be pre of certain Chemical Systems," by M. M. P. Muir. pared 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 simulta. neously with the formation of the yellow solution. From

CORRESPONDENCE. his experiments the author concludes that lead tetra. chloride 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

ARSENICAL WALL PAPERS. chlorine or bromine in the presence of sodium acetate as a means of quantitatively determining lead by precipita.

To the Editor of the Chemical News. tion as peroxide, in cases where the use of sulphuric acid SIR, I have read and heard of a good many cases of is unadvisable, and gives results obtained: by thus preci.reputed poisoning from arsenical wall papers, but have pitating a solution of lead acetate (in the presence of neyer till now met with a case myself. It would seem sodium acetate) as peroxide, igniting the latter to prot- that some people are more susceptible than others. I oxide, ånd weighing 54:71 and 54:67 per cent Pb were have slept for months in a room the paper of which obtained, theory indicating 54:67.

contained an enormous quantity of As without experi. Thé PRESIDENT remarked on the importance of the encing any ill-effects therefrom, although I could easily suggestion as to the use of Br and Cl for precipitating | rub the colour off with my finger—but to my case. lead from solution, as in many cases sulphuric acid did A lady in this town complained of a peculiar feeling of not completely precipitate lead.

constriction in her nose, accompanied by a “nasty smell," After a short discussion, in which Drs. Wright and nausea, and loss of appetite, and was unable to discover Tilden and Messrs. Hartley and Neison took part, Mr. the cause. The symptoms had been felt since sleeping Fisher replied.

in a certain room, which she had done for two months. The SecreTARY then read a short note by Messrs. DALE Somebody, I believe, suggested arsenical paper. I exand SCHORLEMMER, “On the Transformation of Aurin amined the paper and found a very large quantity of As, into Trimethyl-pararosanilin." This transformation was more than I have ever found in any paper before. H2S effected by the action of an aqueous solution of methyl. I gave at once a brilliant orange precipitate. Under the amin, at 125°, on aurin, a purple colour being formed circumstances I could do no less than recommend that possessing all the properties of a trimethyl-rosanilin. , the paper should be removed, but I wanted her to try the Intermediate compounds, soluble in alkalies, were simulta. 1 experiment of sleeping in another room for a time to see neously produced, and are at present under investigation, | if the symptoms disappeared, and then return again to see

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