Obrazy na stronie

No. I.

No. 2.

June 13, 1879.
Nitroger. Iodide.


a large excess of the strongest liquid ammonia kept at or By J. W. MALLET.

below 0° C. by a freezing mixture, the liquid poured off from the easily subsiding black powder, and replaced two or

three times by fresh solution of ammonia. The powder The various researches upon the highly explosive black was then at once transferred to a corked flask, and shaken substance formed by the action of iodine upon ammonia up repeatedly, first with alcohol of 95 per cent., then with have, as is well known, led to diflerent views of its com- absolute alcohol, and finally with anhydrous ether, all of position. That first put forward by Colin and Gay- these liquids being artificially cooled. Most of the last Lussac, nainely that it is nitrogen tri-iodide, appeared to portion of ether, which, as well as several of the preceding have been set aside by the experiments of Serullas," washings, was perfe&tly colourless, having been decanted Millon, f. Bineau, Gladstone, ş Playfair, and Bunsen, lloff, the Auid black mud was turned out upon a fi.ter, all of whom found hydrogen to be a constituent, but in drained in a few moments, and the remains of the ether varying amount, the formulæ NHI2-NH2I-NH3.N13–swept away as vapour by placing the filter and contents and NH3.4N13 having been assigned to the produas under a receiver and drawing cold dry air through in a obtained by somewhat different processes, until more rapid stream. This use of alcohol and ether to rerecently Stahlschmidt T has revived the statement that move water from the iodide after its formation is not under certain conditions at least the simple tri-iodide is to be confounded with the employment by several exformed.

perimenters of alcoholic solutions of iodine or ammonia, One source of error in the analysis of this instable com- or both, in making the substance in the first instance. pound seems to have received insufficient attention from The product thus obtained was explosive in the some of those who have examined it, and somewhat highest degree, yielding to very slight friction upon paper, affects the conclusions drawn from the experiments of frequently producing a crackling sound from little partial others. The substance, obtained as a black powder by explosions when it was gently rubbed under water, and the action of iodine on ammonia, decomposes gradually in two instances exploding in some quantity under water, in contact with water, nitrogen gas being slowly evolved, with much violence and complete shattering of the iodine liberated, and iodic and hydriodic acids or ammo.

vessel. nium salts formed. This decomposition takes place to no The relative quantities of nitrogen and iodine were inconsiderable extent during the drying of the powder at ascertained by decomposing an unweighed parcel of the ordinary temperature, and may be readily proved to have substance by a moderately strong aqueous solution of occurred by treating the dry residue with any of the sol. sodium sulphite, neutralised by dilute sodium hydrate, vents for iodine, as for instance alcohol, chloroforn, or and determining, in equal volumes of the liquid, the ni. carbon di-sulphide, which at once form deeply coloured trogen as ammonia (expelled by boiling with excess of solutions. Hence the air-dried powder is really a mix soda, and collected in sulphuric acid of standard strength), ture of the original substance or substances with various and the iodine as silver iodide. decomposition products, and so is unsuited for accurate A—In three experiments were obtainedanalysis. On the other hand, it might be doubted in

No. 3. regard to the analyses made of freshly prepared and still moist iodide, whether the results apply to a substance


Oʻ126 O'184 0'172 grms. capable of being obtained in the dry state without de

Equiv. to


O'104 0'152 0'142 composition.

Ag 1
5'126 7607

6.889 Millon and Bineau, it is true, seem to have aimed at

2771 4'112 3723 guarding against this difficulty by drying the materials, Nos. 1 and 2 refer to the same lot of material (separately side by side with solid potash, under a jar of gaseous decomposed, however) ; No. 3 to the product from a ammonia. Bineau remarks that some of the gas is at repetition of the same process. first absorbed by the water moistening the powder, but These numbers correspond to that as the drying proceeds the gas recovers (“ à peu

No. 1. No. 2. No. 3. Calc. for NIz. près "') its original volume, and that so moisture is gotten rid of without the iodide being decomposed. But, with

N (assumed) 14'0 14'0 14'0 14'0

I out qualitative examination of the gas, or a very accurate

373'02 378.74 367'04 38140 determination of its volume, this does not afford satisor, for i atom of nitrogenfactory proof that the dry substance is unchanged. I

No. 2. have observed continuous, though slow, evolution of little Atoms of iodine

2'94 2'98 2.89 bubbles of nitrogen from the freshly prepared powder when kept under strong aqueous ammonia, though in this case

B-Another specimen, similarly prepared, but with no free iodine can be found, since as fast as it is liberated weaker ammonia, without any precaution as to cooling the it reacts with the excess of ammonia, reproducing the materials used, and in a room the temperature of which nitrogen iodide, and forming more ammonium iodide,

was about 23° C., gavewhich latter therefore tends to accumulate in the liquid,

No. I. and is thus to be found in the residue from drying up a moist ΝΗ,

0'174 0152 grms. mass of the powder in an atmosphere of ammonia.

Equiv. to N

0'143 0'125 I have applied a different method, which is often useful

5'935 5'467 under other circumstances, for quickly getting rid of

Equiv. to i

3'208 2'955 water, namely repeated and rapid washing with

absolute alcohol, followed by ether, and final evaporation of the last.

corresponding to named volatile liquid.

N (assumed) 14'00 14'00 20 or 30 grms. of iodine was dissolved in a minimum of

314'07 330'96 95 per cent. alcohol, and precipitated by pouring into a or, for one atom of nitrogenlarge volume of cold water. The finely divided iodine was washed several times by decantation, then gently

Atoms of iodine 2'47

2.61 triturated for several minutes in a porcelain mortar with C-Two other specimens, washed at first, not with alco.

ho and ether, but simply with water until no free am. * Ann. Ch. Phys. [2], 42 ; 200 (1829).

monia could be detected in the washings, then kept under + Ann. Ch. Phys. [2], 69; 78 (1838).

water for two or three days at ordinary temperature, i Ann. Ch. Phys. [2], 70; 270 (1838); and (3), 15; 71 (1845). Š Chem. Soc. 6. Fourn., 4; 34 (1851).

with occasional stirring, and finally dried after washing il Ann. Ch. Pharm., 84; 1 (1852).

out with absolute alcohol and ether, as above described, Pogg. Ann., 119; 421 (1863).


Equiv. to i

No. 1.

No. 3.

No. 2.

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No. 2.

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N 4622 H 0'15

Softening of Magnesia-Hard Water. {

June 13, 1879.

Experiments of Bunsen (first product, using anhydrous NH3 0'136 0'127 grms.

alcoholic solutions of ammonia and iodine). He Equiv. to N O II2 0*105

himself assigned the formula NH3.N13. Ag I



to i
2'137 1'982

I-N=N-H, 1-N=N-H. corresponding to


N (assumed).. 14:00 14:00

It is much more doubtful whether we should add-

267*12 264-27 or, for i atom of nitrogen

Experiments of Milon (in 1838). The product dried under

a receiver filled with gaseous ammonia had lost its Atoms of iodine 2'10


extreme explosiveness, and no doubt contained an. Of the above results

monium iodide. A distinály represents the atomic ratio N:I=1: 3,



H fully confirming Stahlschmidt's conclusion that the

FN=N tri-iodide can be obtained quite free from hydrogen.

I-N=N-H, or H-N=N-H.


-1 B corresponds well with N:1=2: 5, and C with the proportion found as the result of several | It appears that, not only may these different products be earlier experiments, N:I=1:2.

obtained by varying the conditions under which the for. If В be admitted to stand for a definite compound, andmation of the explosive substance is effected, but during not a mere mixture of A and C, which is rendered proits decomposition by water, certainly involving more than bable by the fairly close agreement of the results obtained

a single series of reactions, one of these products may be with the calculated figures, there must be two atoms of

more or less converted into others.--American Chemical nitrogen in the molecule, and the formula will be N, HIş: Fournal. This formula may almost as well be deduced from Bunsen's anaylsis of one of the products he obtained (by addition

University of Virginia, Peb. 21, 1879. of ammonia to a solution of iodine in nitro-hydrochloric acid, diluted with water, and rapidly washing with cold water) as that which he has himself assigned, viz., NH3.4N13, since the figures standCalc. for N,H1). Calc. for NH3.4NI. Found by Bunsen.

SOFTENING OF MAGNESIA-HARD WATER. 4:38 0.008143 or assumed 4:38

By J. GROSSMANN, Ph.D. 019 I 95.63 95.43 0'174417

93.82* I have lately had an opportunity of making some experi

ments on the softening of so-called magnesia-hard water

by Clark's process. Although from a theoretical point of It will be seen that the figures of the formula now pro- softed as easily as ordinary lime.)hard water, it was

view there is no reason why such water should not be posed differ less from those of Bunsen's fcrmula than the thought convenient to try the experiment on a somewhat latter do from the results of experiment. In view of the general fact that the compounds of ni- large scale, especially as I have not been able to find

any experiments on the softening of magnesia-hard trogen in which this element behaves as a pentad are

water have been published before in detail. those in which instability, is chiefly observable, and

The water in question is pumped from a colliery at noticing the various proportions in which the iodine and Collins Green, near St. Helens. The bottom of the well hydrogen have been found together united with it, it seems

is about 964 yards from the ground, and I give for comfairly probable that the molecule of each of these explo, pleteness sake the different strata, as well as the quantity sive compounds contains two pentad nitrogen atoms; and of lime and magnesia per hundred, which hydrochloric reviewing all that has been published on the subject, with acid dissolved out of them, the samples being previously attention to the sources of error connected with the dried at 240° F. various methods used, we seem to have established the

P.c. CaO. Pc. Mgo. Yards. following series of substituted products, beginning with the tri-iodide :

Depth of alluvium and clay from
surface of ground to top of the

17 Experiments of Stahlschmidt (using aqueous ammonia)

red sandstone .. and those now reported (A).

New red sandstone


0'24 34
Yellow sandstone

13 I-N= N-I.

Compact red sandstone

472 0937
New marl or metal


0:52 6 Dun Rock

0:40 0°46 Experiments of Bunsen (second product), and above Coarse porous red sandstone 1.88

13 result (B).

Coarse red sand ..

0*72 0'32


This water is organically very pure and contains only Experiments of Bineau, Stahlschmidt, Gladstone (using small quantities of chlorides and sulphates. The hard.

alcoholic solutions of ammonia and iodine), and above ness is almost entirely temporary, though in estimating result (C).

the permanent hardness it is sometimes difficult to remove I -H Н.


the lime and magnesia by boiling. I may as well point 1-N=N-H, or, I-N=N-I 1

out in this place a common fallacy, which is that hard -1 I=N=N=;

water by being boiled before being used for domestic pur.

poses becomes soft. As it is generally only healed to There seems to be an error in the calculation of the percentage of boiling just before being used for washing or cooking it iodine in the original paper (Ann. d.Ch. u. Pharm. ; 84; 1), but the makes not much difference in the hardness of the water. figures here given are correctly deduced, I believe, from the actual weighings quoted, viz., 0-1300 grm. of ammonio chloride of platinum The following is taken from the Sixth Report of the Com. and 0'0732 grm. of palladium.

missioners appointed in 1868 to inquire into the best



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June 13, 1879.
) Analysis of the Water of St. Dunstan's Well, Melrose.

259 means of preventing the pollution of rivers. Thirteen water softens as well and as easily by Clark's process as samples of water drawn on thirteen different days from ordinary lime-)hard water. the kitchen boiler of a dwelling-house, and from that of - I wish to point out here that in my opinion, with our the Athenæum Club, were found to be usually nearly as present knowledge of the behaviour of magnesia-hard hard as the cold water with which those boilers were water towards soap solution, the hardness test in cases of supplied, as is seen from the following results :

water of that description cannot be relied on in any way.

Mr. Wanklyn, in his book “On Water Analysis," says Hardness of Hardness of Hardness of Hardness of Cold Water.

that magnesia takes up as much soap as it equivalents Hot Water. Cold Water. Hot Water. 14:6 13:6

of lime would take up. If that were so the Collins Green 15'4



water should have tested 35'9° total hardness, instead of


23-3°, which it gave on the most careful testing. It will


be noticed that this is even less than the water would

require if it contained an equivalent of lime for the 14'4 II'7 1897

magnesia present ; for the calculated hardness would then 14'4

be 29'4o. It appears to me that in the case of magnesia.

hard water a determination of the lime and magnesia is I boiled Collins Green water that tested 27.8° total the only means of showing the quality of the water. On hardness in an ordinary tea-kettle for five minutes, and the other hand, I quite agree with Mr. Wanklyn in putting even that exceptionally temporary-hard water tested then little reliance on the distinction between temporary and still 17o6° total hardness. The experiments for softening permanent hardness, unless the estimations ha

been this water by Clark's process were made in two series; performed very carefully ; and there are

in in the first milk of lime was used, and in the second lime- which, even with the most careful working, figures for water. The milk of lime was prepared by mixing 5 lbs. temporary and permanent hardness may be got which are of slaked lime of 70 per cent CaO with 6 gallons of Collins not trustworthy. Green water. In performing the softening of the water the milk of lime was gradually added to the water during the operation, the mixture being well agitated during the whole experiment.

ANALYSIS OF THE In three experiments the hardness was reduced from WATER OF ST. DUNSTAN'S WELL, MELROSE. 23'3° which the water tested originally to 5'0°, 5'5°, and

By WILLIAM JOHNSTONE, F.C.S., F.I.C. 5o7o. The total solids were reduced respectively from 33-9 to 13.0, 33.6 to 12-2, and 33:6 to 13.6 grs. per gallon. The softened water, after it had been standing in stoppered An exhaustive analysis of this strongly ferruginous saline bottles for a few days, formed a little deposit, and its carbonated water has not, so far as I have been able to hardness was then 3'5° in all cases. The analysis learn, been published before, although a general analysis showed that then the lime had been reduced from 9-13 to of it was made by Mr. J. Dewar in 1870, and published 1.62; the magnesia from 5'23 to 0'23 grs. per gallon. in the CHEMICAL News, vol. xxiv., p. 171. There has

There were used on an average 1465 gallons of water been a partial analysis of this water also by Dr. Stevenson to 3.5 lbs. of Cao, corresponding to 2:67 lbs. of lime of Macadam, of Edinburgh, but as his results are very 90 per cent per 1000 gallons. Theoretically to precipitate doubtful I refrain from quoting it at all. As this water the lime and magnesia as far as I have done in my is peculiar for the large quantity of iron it contains, and experiments would require 2'31 lbs. of Cao per 1000 as its composition seems to have varied considerably gallons.

since it was examined by Prof. Dewar, it is thought that The experiments for softening with lime-water were another and more complete analysis will not be out of carried out in a similar way. A measured quantity of the place. lime-water was put into the mixing tank, and the Collins Melrose is a village of some 2000 inhabitants, and is Green water run into it until nearly all the lime of the situated at the base of the Eildon Hills, in the valley of former was taken up, which in these experiments as well the Tweed; one of those lovely spots that are said to be as in those with milk of lime was ascertained by the well particularly favourable to the curative effects of medicinal known silver test. The mixture was well agitated during waters. The surrounding country consists principally of the whole experiment. A great advantage in working richly variegated fields, and the entire distriã teems with with lime-water is that it requires less agitating than objects of natural beauty, while every spot on which the working with milk of lime.

eye rests is associated with some incident of historic or In four experiments the hardness was reduced from classic interest—the ecclesiasticism and chivalry of the 23.3°, which the water tested originally, to 3'5°, 33°, 3.5°, past, and the interest conferred by Scott in the present. and 3.5o. The total solids were reduced respectively The salubrity of the district is well known, and the from 34'3 to 12.0, 34'4 to 112, 346 to 12.o, and 34°7 to romantic scenery, which is equalled by few places in the

The lime had been reduced from 9:07 to 1.67, and kingdom, presents a picture dear to the lover of nature as the magnesia from 5'24 to 0-18 grs. per gallon.

well as to the invalid. There were used on an average 1670 gallons of water The spring, which belongs to Mr. John Turnbull, of on 530 gallons of lime-water, which latter having been St. Dunstan's Cottage, Melrose, was accidentally disexposed to the air for some time before being used tested covered in 1870, when sinking a shaft for ordinary spring only 60 grs. CaO per gallon. This corresponds to one water. The water is said to be uniform in quantity, its volume of lime-water of 60 grs. Cao per gallon to temperature varies only within very narrow limits, and is 3:15 volumes of Collins Green water, or corrected to go grs. quite cold. As it occurs in the spring it is perfe&ly clear, of CaO per gallon, which strong lime-water should con. of a yellowish colour, but, after exposure to the air, tain, the proportion of lime-water to Collins Green water deposits the iron as a ferric mangano-manganic oxide; would be i to 472. This result is not quite correct, as it has a strong powdery odour and a decided inky taste. the lime-water had undergone a further susceptible de. When taken from the well there is a disengagement of small composition while lying in the mixing-tank; so that at the pearly bubbles, and on being shaken up in a closed bottle time of its a&tion on the Collins Green water it contained liberates a large quantity of gas. The temperature of the less than 60 grs. CaO per gallon. Both in working with spring on October 5, 1878, was 50° F., the temperature of milk of lime and lime-water the softened water settled the air at the same time being 62° F. The specific perfe&ly clear after three to five hours, taken from the gravity of the water is 1001'9356. A careful qualitative time that the agitation was suspended.

analysis indicated the presence of the following con. From these experiments it follows that magnesia-hard | stituents in estimable quantities :


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260 Contribution to the Theory of Fractional Distillation. {

June 13, 1879.
Barium sulphate

or Elements replacing them.
Strontium sulphate

Calcium sulphate

Sulphuric acid
Magnesium sulphate



Magnesium bromide

Magnesium iodide..

0'000945 Lime

Potassium chloride

Lithium chloride

Ammonium chloride

Sodium chloride ..

Ferrous oxide
Magnesium chloride

0'027528 Manganous oxide

Aluminium phosphate

0'019503 Calcium phosphate

O'012511 In addition to the above were found traces of fluorine, Calcium carbonate

0'028544 butyric and phosphoric acids, along with other volatile Magnesium carbonate

0'037205 and non-volatile organic matter.

Ferrous carbonate..

0'529553 The residue of 30 gallons was examined by means of Manganous carbonate

0'001278 the spectroscope for cæsium, rubidium, and thallium, but Silicic acid

0'027866 the search proved unsuccessful. The method of quanti- Crenic acid

0'013572 tative analysis employed was essentially that described by Apocrenic acid

0.000487 Fresenius under the head of “ Analysis of Mineral Waters" in the last edition of his “Manual of Quantitative Total ingredients calculated

I'420519 Analysis.”

The following figures represent grammes per litre, and but at the same time I may mention that a considerable are the average of three determinations of each of the sum of money has been expended in the view of preventing principal constituents, done in order to guard against any more surface-water entering the well, so hope at some error and to ensure accuracy; the amount of water taken future date to be able to favour you with another analysis, for the several determinations was, whenever pra&icable, ascertained by weight.

Results of Analysis. Chlorine ..


0:378243 Bromine ..

0'000305 Iodine

0'000788 Sulphuric acid (SO3)


CHEMICAL SOCIETY. Carbonic dioxide (total)


Thursday, June 5, 1879. Silicic acid

0'035286 Ferrous oxide..


Mr. Warren De la Rue, President, in the Chair. Lime and strontia expressed as car. bonates

o'103842 After the transaction of the usual business the following Magnesia (total)

0.056216 certificates were read for the first time :-E. Buckney, Lime precipitated as carbonate on

R. E. Holloway, T. Blackburn, E. F. Mondy, E. Francis. boiling..

0'028544 It was announced that a ballot for the election of Fellows Baryta

0'002917 would take place at the next meeting of the Society Strontia

O‘000886 (June 19). Manganous oxide

0'000785 The following papers were read :Phosphoric acid

0.020085 Alumina ..

A Contribution to the Theory of Fractional Distilla. 0'006582

tion," by T. E. THORPE. Wanklyn some years ago found Lichia


that when two liquids of different boiling-points were mixed Potash


together in equal quantities by weight and distilled, the Soda..


proportion of each constituent in the distillate was the Ammonia


product of its vapour-density and vapeur-tension at the Total fixed constituents

temperature of ebullition of the fraction. Hence, under

I'390000 certain circumstances the less volatile of the two sub. Following the arrangement adopted by Fresenius on the stances may pass over most rapidly, whilst if the vapourassumption that the strongest acids are united with the tensions and vapour-densities of the two liquids are instrongest bases, &c., and allowing for the fact that the versely proportional the mixture will distil unchanged. more or less degree of the solubility of the salts decidedly Berthelot observed that a mixture of 90-9 parts of carbon influence the manifestation of the affinities, and in order disulphide with gör parts of ethyl alcohol boiled and disto simplify reference and comparison, and by way of con

tilled as a homogeneous liquid. An instance of this phetrast, i append the results calculated as grammes per equal volumes of carbon tetrachloride boiling at 76-6", and

nomenon has been noticed by the author. A mixture of litre. (See next column.)

of methyl alcohol boiling at 65.2°, was distilled. It was Gases dissolved in the water and expelled by ebullition found that 46.5 per cent of the whole boiled constantly in vacuo measured at 59° F. and 760 m.m. barometer.

between 55-6° and 55'9", 10° lower than the boiling-point Cubic centims.

of the most volatile constituent. This mixture contained Carbonic dioxide

78:1 per cent carbon tetrachloride and 2149 per cent methy!

101'434 Oxygen


alcohol. This proportion, 3.6 to 1, is almost identical Nitrogen ::

with that obtained by multiplying the vapour-tensions of 31'250

the two liquids at the temperature of the boiling point of

the mixture (5587°) by their respective vapour densities, 139477

4874 15'97: 372-4 x 76.69::1:367. The distillation of I am unable at present to form an opinion as to whether the residue in the Hask was continued by Mr. C. C. Starthe composition of the water is constant, owing to the ling: at first principally carbon tetrachloride, finally pure surface-water having had free admittance to the well pre- methyl alcohol passed over. The author suggests as a vious to the collection of this sample on March 18, 1879, I striking le&ure experiment the following:- Three baro


Maximum rate

with Co.

with H.




Chemical Dynamics. June 13, 1879.

261 meter tubes are filled with miercury.

Into one

racter is that of a sigmoid. For a certain time there is methyl alcohol is passed ; into the second some carbon no perceptible action; this time is the longer the lower tetrachloride; into the third a mixture containing by the temperature. Reduction then commences languidly, volume 3 parts of methyl alcohol to 5 of carbon tetra- | quickly accelerating until a maximum of activity is reached, chloride: the depressions of the mercury column are 80, after which it diminishes until almost perfect deoxidation 70, and 130 m.m. respectively. The author promises a is effected. The maximum rate of action with hydrogen further research on the physical peculiarities of this lies about 10 per cent (out of 19'74 per cent) of oxygen orimixture.

ginally contained in the copper oxide, and about 7 to 8 " Preliminary Note on the Action of Organo-zinc Com- per cent in the case of carbonic oxide. This apparently pounds on Quinons,” by F. R. JAPP. When finely-powdered indicates that hydrogen passes through the outer and parphenanthren quinon is gradually added to zinc ethyl, diluted tially reduced surface of particles to their interior more with ether so as not to be spontaneously inflammable, a

readily than carbonic oxide. The following numbers reaction takes place with evolution of gas. The orange

illustrate the maximum rates of reduction attained, the colour of the quinon disappears: a whitish powder is gaseous currents being competent to remove 0'7791 per cent formed, which sinks to the bottom of the liquid. On de- of oxygen (out of 19974) per minute :composing this product with an excess of alcohol, boiling,

Maximum rate and filtering hot, transparent, faintly yellowish, rectangular

Temperature. plates were obtained, fusing at 77°, and having the formula

Per cent per minute. Per cent per minute. C18H2003. This formula can be resolved into



0'380 The compound C16H1402 has not yet been obtained pure ;


0:480 Ібоо

O'118 but the monacetyl derivative, C16H1302(C2H30), has been

0570 prepared and analysed; it fuses at 103°. The author


0'270 refrains at present from discussing the constitution of the


0-490 compound C16H1402, but suggests that these reactions


0-700 may serve to distinguish quinons from double ketons. He intends, also, to study the action of organo-zinc com- The higher the temperature the nearer does each curve pounds on other quinons and allied substances as di- approximate towards a limiting straight line, which would benzoyl.

be attained did deoxidation commence immediately and go After some remarks by Dr. ARMSTRONG on the interest on at such a rate that all the hydrogen was converted into and probable bearing of the above reaction,

water, and the carbonic oxide into carbonic acid. The Dr. Wright read a paper entitled “ Third Report to the version of about nine-tenths of the H into H20, &c., of

highest rates of reduction attained corresponded to a conChemical Society on Researches on some points in Chemical CO into CO2. From the curves it is evident that, cæteris Dynamics (On the Curved Surfaces expressing the Relations between Time, Temperature, and Amount of De: paribus, to perform a given amount of deoxidation with oxidation of Copper Oxide by Hydrogen and Carbon hydrogen requires either a higher temperature or a longer Oxide),” by C. R. A. Wright, A. P. LUFF, and E. H. of incubation” during which no action takes place, and

time than with carbonic oxide. The existence of a period Rennie. This is a continuation of the previous reports by the acceleration in the rate of action to a maximum, &c., the authors on the subject. In the present paper a large shows that what has been termeil " Chemical Induction number of observations have been made by reducing a uniform weight (I'15 grms.) of copper oxide (prepared by by Bunsen and Roscoe takes place in these cases to a large

From igniting pure copperı nitrate) in narrow glass U-tube's extent, dependent in amount on the temperature. heated to known and constant temperatures in vapour experiments now in progress this does not appear to be the baths : in some cases water and paraffin baths were em.

case when copper is oxidised by hot air. A number of ployed fitted with Page's gas-regulator. Equable streams

observations were made on the effect of varying the speed ot hydrogen and carbonic oxide were obtained by bubbling oxide used, with the general result that a more rapid

of the current of reducing gas and the weight of copper the gas through a wash-bottle, the stream being adjusted by a screw-clamp, and counting the bubbles. The average

stream or a smaller weight of copper oxide corresponds to rate was 12'5 c.c. per minute. By plotting

out the results Heating the copper oxide just before use causes great

an increased percentage of deoxidation, and vice versa. thus obtained in space with reference to three planes mutually at right angles, so that the distance from each irregularities in the action. A large number of observaplane represents, respectively, the time of exposure, the

tions were made by enclosing the copper oxide in sealed temperature, and the percentage loss of oxygen. Points tubes filled with the respective gases, heating for different are marked on curved surfaces, the sections of which, periods, and determining whether reduction had taken parallel to the three primary planes, represent respectively, The times are perceptibly longer than those found in the

place or not; thus the following numbers were obtained. ihe amounts of oxidation produced in giver times at a constant temperature, the times required to produce given corresponding U-tube experiments; in every case the time amounts of deoxidation at constant temperatures, and the

at any given temperature is less with CO than with H. amounts of deoxidation produced at given temperatures in

With CO, period With H, period

Temperature, a constant period of time. The paper was illustrated by

of Incubation equals about

equals about tables, diagrams, and models of the curves thus produced,

160° 12 minutes 80 minutes the mode of experimentation adopted being to determine

130 for a constant temperature the amounts of deoxidation


6 hours

118 produced in varying times. At and above 160° in the case

67 hours 71

28 of hydrogen, and 130° in the case of carbonic oxide, the


180 curious result was arrived at that the same mean curve is obtained whether the exposure be made all at once to a Attempts were made to trace out curves illustrating the temperature for a time, T, or in periods of time ts, ta, tz, rate of reduction at various temperatures in atmospheres &c., which are together equal to T, provided that the in containing more reducing gas than would suffice to de. terval between the periods is not too long (ten minutes). oxidise completely the Cuo. The results were not very Below the above temperatures the deoxidation in an hour concordant, but indicated that the action here is still of the is greater than that produced in two consecutive heatings same kind; i.e., a period of incubation exists, after which of half an hour each with an interval between. The action commences, reaches a maximum, and then falls off ; curves obtained with hydrogen and carbonic oxide re- in other words, chemical induction takes place whether the semble each other in certain respects ; their general cha- I metallic oxide or the reducing gas be at any given moment

of Incubation

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