Obrazy na stronie

ws,} Aragonite on the Surface of a Meteoric Iron.

87 Sept. 1, 1876. The greatest practical difficulty in the Deacon's chlorine, two of the northern provinces of Mexico; the Deser process lies in the enormous volume of gas which has to being 400 miles from east to west, and 500 miles from be dealt with, and consequently in the large dimensions north to south, bordering on the Rio Grande. This region, required for the chloride of lime chambers. But Deacon so prolific in masses of meteoric iron, has been described has endeavoured to combat these difficulties. He compels by Prof. Burckhardt, of Bonn, as well as by !nyself. the gases to take such a course that they are systema- In 1854 I described three of the masses (Amer. Yourn. tically deprived of chlorine. They meet at first with of Science and Arts, vol. xxviii., p. 409): two of these chloride of lime almost saturated, then, as they lose their have been brought to the United States, one weighing chlorine they pass over lime less and less chlorinised till 125 kilogrms, and the other 630 kilogrms. In 1868 eight they finally pass out into the atmosphere completely ex- others were brought to this country, the heaviest weighing hausted over fresh hydrate of lime. The arrangements 325 kilogrms. These I described in 1869 (Amer. Fourn. by which this systematic saturation of the lime is pro- of Science and Arts, Nov., 1869); and 1871 I was duced are of a twofold nature. In the first place enabled to give a description and an analysis of a still chambers are employed in which the lime lies on gratings larger one, weighing about 3500 kilogrms., this last one and which are so connected with each other that the remaining on the western boundary of the Desert near chlorine streams through them successively. As soon as El Para. the lime in the chamber nearest the generating apparatus We have some account of one even larger than the last, is saturated it is thrown out of connection with the current located in the very centre of the Desert. So far as known of chlorine, is charged with fresh lime, and takes its place there have been found in this locality not less than at the end of the series, whilst a chamber containing lime 15,000 kilogrms. of meteoric matter, an amount exceeding nearly saturated receives the concentrated portion of the that which has been brought together in cabinets from all gaseous current. The second kind of methodic saturation other sources. is the following, in which is applied the principle of When I examined the eight masses in 1868, I noticed a Hasenclever and Helbig's pyrites furnace :

white crust on a small part of the surfaces of two of In a tower are several stories of sloping plates of slate, them, but at that time I could not make any critical forming a smaller angle with the perpendicular than the examination of it. Within the past few months these outer surface of the heaped up chloride of lime is capable irons have come under my control, and therefore I have of taking. In every story the direction of the plates, been enabled to examine the points that had been omitted, which are parallel to each other, cuts the plane of the the most interesting of which forms the subject of this plates, likewise parallel to each other, in the next higher communication. and next lower story. Thus intervals are produced which On one of these masses of iron, weighing 210 kilogrms., extend in zigzag from below upwards. At the lower end there is a small amount of a white incrustation covering of each of these intervals is a shovel-wheel by whose about 15 square centimetres of the surface; and on anorevolution the speed of a powder sliding over the plates ther. weighing 275 kilogrms., there is an incrustation, can be regulated. Into this tower the lime is thrown by which covered originally over 200 square centimetres of means of a hopper and slips from plate to plate till its the surface, attached firmly to the iron, and when broken further fall is stopped by the rollers. But as the falling off (as most of it has been by careless handling of the lime cannot form so acute an angle with the perpendicular mass) it brings away with it on the under surface a portion as the plates it does not completely fill the interstices, of the iron that has become oxidised : its thickness is but leaves in every link of the zigzag a wedge-shaped from 1 to 5 m.m. space, through which the gases are compelled to ascend It is quite hard, scratching calc spar very readily; the from stage to stage. Hence, as the lime moves constantly surface of it is irregular and granular. If broken perpendownwards in an opposite direction to the current fresh dicularly to the surface of the iron, and ground down, it lime enters above, and saturated chloride is taken out will receive a very good polish, showing an irregular and below. To obviate incidental stoppages in the motion of wavy structure on many of the pieces, and parallel to the the lime there are here and there in the tower openings surface of the iron, with yellow and dark brown streaks fitted with valves. This apparatus can scarcely be like the Gibraltar limerock'; it effervesces with acids, and adopted in pradice, as chloride of lime, from its tendency is an incrustation of aragonite. to clog together, moves but slowly down an inclined plane, The following is the composition of the mineral :whence frequent stoppages would be inevitable.

Carbonate of lime

9310 The last mentioned apparatus, suitably modified, is recommended by Deacon for the preparation of salt-cake

Sesquioxide of iron

trace from diluted chlorine, sulphurous acid, steam, and salt.


Insoluble residue.. Instead of lime he causes salt to glide down a tower

Water strongly heated, whilst a mixture of diluted chlorine, sulphurous acid, and steam ascends.

As regards its formation, I am satisfied that the crust The hydrochloric acid thus formed is condensed and has been made on the iron since the fall of the latter. re-converted into chlorine, whilst the sulphuric acid Conceiving this to be the case, I desired to know the naformed by the oxidation of the sulphurous acid converts ture of the rock and soil where these meteorites were the salt into sulphate.

found, and I have been able to gather the following parti(To be continued)

colars from Dr. Butcher, who collected the specimens under examination :This spot is in an alluvial valley or

plain between two ranges of high mountains running ARAGONITE ON THE SURFACE OF A

parallel with each other, varying in distance from i to

3 miles. The mountains at the base are calcareous in METEORIC IRON, AND A NEW MINERAL

formation, and in the hills and plains there are large cal. (DAUBREELITE) IN THE CONCRETIONS OF careous deposits. The plain in many places is cut up THE INTERIOR OF THE SAME.

with deep ravines, and several of the specimens of iron

were found among the stones and sand at the bottom of By J. LAWRENCE SMITH, Louisville, Ky.

the ravines, and during heavy rains were washed or

covered with water. It is, however, only in wet seasons I. Incrustation of Aragonite.

that the water is found remaining in the ravines and deThe remarks in this communication have reference to pressions of the valley, and this water is always brackish some of the masses of iron that have been brought from to the taste, containing a large amount of mineral matter. that region of Mexico called the Bolson de Mapini, or the Without giving any further details of the nature of this Mexican Desert, situated in Cohahuila and Chihuahua, region of Mexico where these meteorites were collected,


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Dinitro-Para-Dibrombenzols and their Derivatives.


Sept. 1, 1876. sufficient has been stated to show the probable source of express its true composition :-Sulphur, 37•62 ; chrome, the calcareous incrustation which I discovered upon two | 62'38. of them.

This mineral is an interesting one, and is found in a This incrustation on meteorites has been discovered but very strange place; yet from what is revealed to us by the twice before, and in both instances by myself. One of spectroscope with regard to the vapours surrounding the them, however, is of so obscure and unsatisfactory a cha- sun, the element chrome must be widely diffused in the racter that I have not given any public notice of it. The matter of the universe.-American Journal of Science other is the case of the Newton County meteorite and Arts. described by me (Amer. Fourn. of Science and Arts, vol. xl., 1865). It is a meteoric stone belonging to the variety classified by M. Daubrée as Syssidères ; specimens of it have been furnished by me to the museums of the Garden

ON DINITRO-PARA-DIBROMBENZOLS AND of Plants, Great Britain and Vienna, with this incrusta

THEIR DERIVATIVES. tion in well-defined particles of a translucent character

By PETER TOWNSEND AUSTEN. adhering firmly to the surface. The entire amount of this meteorite yet known does not exceed 700 grms., although the primitive mass must still exist in a sparsely Two kilogrms. of pure crystallised solid (para) dibromsettled region of Arkansas, and when obtained will no benzol were divided into portions of 250 grms., and each doubt furnish specimens with a larger amount of the cal. portion added to a mixture of 800 grms. of fuming nitric careous incrustation upon it.

acid and an equal volume of concentrated sulphuric acid,

and then heated on a sand-bath, when a violent action set II. New Meteoric Mineral, Daubréelite.

in, during which it was found advisable to remove the Two of the masses of iron above referred to have been burners. A reddish yellow oil settled in the bottom of the cut across, the section made on one of them being over Aask. After boiling three hours the mixture was allowed 15 square decimetres ; also several transverse cuts have to cool, and then poured in a thin stream into a large been made. In all of these sections a number of nodular excess of cold water. The oil sank to the bottom and concretions have been exposed, most of them quite small, gradually solidified, an operation which may be greatly and hardly any exceeding a centimetre in diameter. At accelerated by vigorous stirring with a glass rod. The the first glance all these nodules have the appearance of nitrited product from 500 grms. of the dibrombenzol, aster very finely crystallised troilite; but a little closer inspec- the washing out the acid with water, was dissolved in tion reveals the fact that most of these nodules have more about a kilogramme of glacial acetic acid, filtered, and or less of a black mineral associated with it. I had never allowed to stand about seventy hours. A copious separaseen anything of the kind before, it being very evident tion of the first (a) dinitro-para-dibrombenzol, containing that it was not graphite. As further examination has a considerable amount of the second (B) isomer, and but proved it to be a new and interesting mineral, I have a small amount of the third (y), took place. By repeated ihought proper to designate it after M. Daubrée, who has crystallisation, first from carbon disulphide and then from done so much in the study and elucidation of meteoric glacial acetic acid, it was obtained perfectly pure. The minerals.

acetic acid filtrate from the first separation contained the Daubréelite is a black lustrous mineral, highly crystal. B- and y-isomers and some of the a. The solution was line in structure, occurring on the borders of the troilite treated with a large excess of water, and the substances nodules, and sometimes running across the centre of in solution were thus precipitated in the form of a yellow them, as may be seen in one of the specimens, where, in oil, which was then separated from the water by means of a nodule of troilite, a vein of the mineral traverses the a stop-cock funnel, heated on a water-bath until it was very centre of the nodule, which is 2 m.m. in width and entirely dry, dissolved in about it kilos. of carbon disul. 12 m.m. long. It has a distinct cleavage, but I cannot phide, and allowed to stand. By standing, a small sepamake out its crystalline form. It is very fragile, and in ration of impure a-isomer generally occurs. The carbon the attempt to detach it from the iron it breaks up into disulphide was then distilled off in portions of 200 c.c., small fragments resembling small particles of molybdenite. and the respective crystallisations, which consisted of the It is feebly attracted in very fine part:cles when a strong B-isomer containing a good deal of the a-isomer and magnet is brought in contact with it. This may arise traces of the y, collected. When no more separated the from the presence of a minute quantity of troilite, which it thick oil was heated on a water-bath until the carbon diis very difficult to get rid of. Pulverised, it furnishes a iulphide was entirely volatilised, after which it was perfectly black powder, the smallest particle of which exposed to a temperature of 5° for three days, when it begives before the blowpipe a very strong reaction of came solid. The mass was carefully rubbed in a mortar chromium. Heated very intensely, it loses its brilliant with ether, at the same temperature, and this ethereal colour and becomes a dull black.

extract (consisting of much y and little B) separated by a The powdered mineral is dissolved completely in nitric filter-pump. The ether was then evaporated, the oil acid. The solution is intensely green, and furnishes a again exposed to the same temperature, and the operation strong reaction of sulphuric acid and oxide of chrome. repeated until the substance dissolved in the ether withThe other strong acids attack it but slightly.

out leaving a residue. The oil was then exposed to a This solubility in nitric acid readily distinguishes it temperature of about – 8° to -10° for nearly two weeks, from chrome iron. The quantity of mineral I was enabled during which small amounts of the B-isomers crystallised to obtain pure, or nearly so, was very small. the reaction out, and were separated by filtering the oil directly with of the acids on the mineral being nearly the same as on

the filter-pump. Finally no more separated from the oil, troilite. I am enabled to separate them only by varying which then appeared to contain only an exceedingly small the strength of the acids, and the length of the time they amount of the B-isomer. are in contact with the minerals. Less than 100 m.grms. were obtained of sufficient pu

Alpha-dinitro-para-dibrombenzol. rity to make out its composition, and this amount furnished The alpha-dinitro-para-dibrombenzol, containing traces me 36-48 per cent of sulphur; the remainder was chrome, of the B-isomer, crystallises from glacial acetic acid in with nearly to per cent of iron and a little carbonaceous beautiful siriated transparent needles, often attaining a matter. This mineral, when obtained pure and in suffi- length of 25 c.m. and a diameter of 3 m.m.

When percient quantity for a thorough analysis (which I hope to fectly pure, however, it crystallises from the same solvent make before longủ, will, I am satisfied, prove to be a in short, compact, white, glittering needles, or small protosulphide of chrome; the iron present being mixed prisms. From carbon disulphide it separates in the form with the Daubréelite. The following, therefore, would l of small, hard, white crystals. The compound is inso.


Sept. 1, 1876.

Dinitro-Para-Dibrombenzols and their Derivatives.



luble in water, easily soluble in boiling absolute alcohol, alcohol with a deep red colour, but separated from the and glacial acetic acid, as well as in benzol and acetic solution as a slimy mass from which no product suscep ether. It is slightly volatile in steam. Fuses at 159° to tible of analysis could be obtained. a transparent slightly yellow liquid.

By the adion of natrium-hydrate solution on the alphao'3034 grm. substance gave 0-0190 H20 and 0-2452 forming red salts, which I take to be a nitro-bromphenol,

dinitro-para-dibrombenzol I have obtained a substance Oʻ1749 grm. substance, after the method of Carius, gave give full particulars.-Amer. Fourn. of Science and Arts.

and concerning which I shall,

at the earliest opportunity, 0.1998 AgBr and o‘0027 Ag.


Royal Laboratory of Berlin.
Calculated for CoH(NO,),Brz.


H = 0.61



The Textile Colourist. Edited by C. O'Neill, F.C.S. In a preliminary notice* I mentioned that a-dinitro

Vol. I. Manchester : Palmer and Howe. para-dibrombenzol, by treatment with ammonia, formed a This is the first half-yearly volume of a monthly paper dinitro-bromaniline, which under the influence of amyl. whose object, as declared in the introductory notice, is to nitrite gave a dinitro-monobrombenzol. By repetition of give an account of what is doing or has been done by the experiments, however, with much larger amounts and practical or scientific men in connection with the dyeing, perfectly pure substances, I find that the reaction is dif- printing, bleaching, and finishing of textile fabrics and ferent.

materials.” Its editor remarks that “some of the existing By treating the a-dinitro-para-dibrombenzol with strong journals do give a little space to articles connected with alcoholic ammonia the crystals take on a light straw. textile colouring,” which is certainly not overstating the yellow colour. By heating in a closed tube at 100° for truth. three hours the reaction is completed. The red solution Among the most prominent articles we may notice obtained was precipitated with water, and the resulting “Critical and Historical Notes upon Turkey Red" taken yellow precipitate crystallised from dilute alcohol. The from the Moniteur Scientific Quesneville, manuscripts of filtrate from the precipitate produced by water gave no Jehan le Begne, a work on dyeing compiled as early as trace of bromine with silver nitrate, but starch and po- 1431, and giving an interesting account of the tinctorial tassium iodide proved the presence of a considerable arts as practised at that time. It proves that a species of amount of nitrous acid.

calico-printing was in use in London as early as 1410. By repeated crystallisations from alcohol the substance The translation, executed by Mrs.Merrifield, must have been was obtained pure. It forms orange, yellow, and red a task of no small difficulty as the receipts are given in needles, which fuse at 75°, and are quite volatile with old French with notes in Latin, doubtless of the mediæval steam. It is very soluble in most solvents, with the ex- type. In one of the receipts quoted we find mention of ception of water, in which it dissolves with difficulty. “ Brazil.” The red wood then used cannot, of course, 0:28 grm. substance, third crystallisation, gave 0'0426 have been obtained from South America, but must have H20 and 0'2536 CO2.

been the product of some Asiatic Cæsalpinia. There is 0-2092 grm. substance, fifth crystallisation, gave, after also a list of British and Irish calico printers in 1840, and the method of Carius, O-2644 grm. AgbBr and

a paper on the “ Manufacture of Carmine or Extract of 0'0008 Ag.

Indigo," from Dingler's Journal. We regret to see the

continental solecism of applying the term "carmine” to Calculated for C,H,Br2(NO).NH,.

preparations of indigo adopted in an English journal,

sometimes even without the qualifying word "indigo." 24.69

The expression “ English sulphuric acid " used on the H=


Continent to express ordinary sulphuric acid in contradistinction to the fuming or Nordhausen kind is unusual

in England. The terin in general use is "oil of vitriol." Amyl-nitrite acts at ordinary temperatures on the nitro. We hope that the existence of the “ Textile Colourist” para-dibromaniline, and forms, not as I formerly supposed, may be considered as a proof of a widening and deepening a dinitro-monobrombenzol, but the ordinary mononitro interest in applied science. para-dibrombenzol. All the properties of the nitro. dibrombenzol (fusing-point 844) obtained in this manner agreed perfectly with those of the well-known mononitro-A Course of Practical Chemistry Arranged for the Use of para-dibrombenzol.

Medical Students. By W. ODLING, M.B., F.R.$. This, as far as I know, is the first case in which the

London : Longmans, Green, and Co. nitroxyl of a nitro-haloid-benzol is substituted by the . amido-group in preference to the haloid atom. În the When a scientific text-book has reached its fifth edition

first series there is, among others, the well-known forma. the duties of the critic lie in a very narrow compass. tion of guanidine from nitro-chloroform by action of That this manual treats of chemical reactions, chemical ammonia, effected by Hofmann.f

manipulation, qualitative analysis, toxicology, and animal It seemed extremely improbable that aniline could act chemistry, with especial reference to the requirements of

medical students and of the medical profession, is generally in a satisfactory manner on the alpha-dinitro-paradibrombenzol, since the disengaged nitro-group would, known. That it has been found satisfactory by professors without doubt, exert a decomposing influence on the of the science may be inferred by the demand for so many aniline itself as well as on the new compound formed. editions. The present re-issue, we are told, has been The dinitro-dibrombenzol was treated with an excess of i carefully revised, the chapter on general analysis by Dr. aniline, and the mixture bɔiled. A strong reaction, at- John Watts, and those on toxicology and animal chetended with a characteristic deep red colour, occurred. mistry by Dr. T. Stevenson. In the analytical chapter Chlorhydric acid precipitated an oil, and, by stirring of this fifth edition, brief, but it is believed for ordinary brown flocks were obtained. The product was soluble in purposes sufficient, directions are now given for the sepa.

ration of the several sub-groups of bases from one another, * Ber.d. Chem. Ges., viii., 1183.

and for the recognition of the several members of these + Ann. Chem. Pharm., cxxxix., 107.

| sub-groups in presence of each other."




C = 24'32


Br= 54'05



CHEMICAL NEWS, Flame of Chloride of Sodium in a Common Fire.

Sept. 1, 1876. We cannot, however, approve of the omission of so remedy would be found much worse than the disease. many of the elements from the plan of the work. It may The true method of dealing with plastered and fortified be argued that as these substances occur neither in wines is to let them severally alone till Andalusian yinemedicines nor in articles of food, and are not likely to be growers banish gypsum from their premises and give us employed whether accidentally or maliciously as poisons, the pure blood of the grape. a knowledge of their reactions and their detections is of Among the genuine, natural wines now coming into use no direct value to the medical man. This is, however, in England, at least, among those who seek in the glass we submit, a somewhat narrow view of the subject. flavour and not intoxicating power, a high rank belongs Furthermore, new substances are continually pressed into to those of Greece. Mr. Denman deserves great credit the service of manufacturing industry and may become for his persevering attempts to bring them under the the subjects of toxicological inquiry. To take an in- notice of the public. No part of the world is better stance :-Vanadium and its compounds were till lately adapted for the cultivation of the grape than the “ Isles of amongst the rarest of laboratory curiosities. Now they Greece," and the wines imported thence are worthy of have been introduced into dye and print works and may their old classic fame. fall into the hands of those ignorant of their highly poisonous nature. Is not a knowledge of the properties of vanadium and the method of its recognition likely to become of importance to the medical practitioner?


Bulletin of the Bussey Institution. Part V., 1876. THE FLAME OF CHLORIDE OF SODIUM IN A
Cambridge (U.S.): Wilson and Son.

Most of our readers are doubtless aware that the Bussey
Institution is an establishment connected with the Har.
vard University, and having for its object the cultivation

To the Editor of the Chemical News. of chemistry, physics, and biology with reference to SIR,—Some time ago a correspondent of Nature (No. 328 agriculture. Its Bulletin is always rich in interesting Feb. 10, 1876) enquired for an explanation of the fact that articles on the composition of soils, manures, and plant- while common salt (chloride of sodium) colours the Same ashes; on the practical effects of manures; on the diseases of an ordinary spirit-lamp yellow, the same substance of cultivated plants and of cattle; and kindred topics of thrown upon a common coal fire gives rise to a blue flame. the highest value both to the practical farmer and to all In the next number (329) Dr. Schuster stated that the who devote their attention to agricultural chemistry and origin of the blue flame was stiil involved in mystery, and physiology. The Institution is evidently doing useful -if my memory is correct, for I have not the number at work, and we wish it a long and successful career. hand-that he and Dr. Schorlemmer had been engaged on

an investigation of the same.

Dr. Schuster's letter shows that the point is not an unHunyadi János ; Aperient Natural Mineral Water. By important one, and as I have lately made a few experiAlois MARTIN, M.D. London: W. Ridgway.

ments which seem to confirm the assumption on which my .Mineral waters are evidently in some quarters coming explanation was based, I beg to solicit space for it in the into increased demand, and very persevering efforts are Chemical News. made to bring certain kinds under public notice. The The theory I put forward is that the blue flame noticed water in question is obtained from certain springs at in the instance of a coal fire (bituminous) on which salt Buda, and contains 137'9 grs. of sulpha:e of magnesia, has been thrown is possibly due simply to the presence of and 128.9 grs. of sulphate of soda per gallon, proportions carbonic oxide (Co), produced by a series of reactions said to exceed those found in all other known bitter through which the common salt is converted into sulphide springs. Its physiological action and therapeutic aç, lica of sodium, as in the manufa&ure of crude carbonate of tions are discussed, and it is strongly recommended by soda (black-ash); all the reactions being performed in one high medical authorities in a variety of ailments.

furnace instead of two, and almost simultaneously.

Leblanc's process consists in-(1) Converting common Wine and its Counterfeits.

salt into sulphate of sodium. (2) The “salt cake " re

By James L. DENMAN, sulting is then mixed with coal and limestone, placed in 20, Piccadilly, London.

a furnace, and heated strongly, during which part of the We have here a pamphlet which all wine drinkers should process a blue flame of carbonic oxide is observed to play read and remember. The author points out clearly and upon the surface. truthfully the real and unpleasant nature of those concoc- In the case we have under consideration the only differtions known as port and sherry which were forced upon ence is that the salt is converted into sulphate of sodium the nation by an unsound system of duties during the by the oxidation of the iron pyrites, from which no coal is latter part of the 18th and ihe beginning of the 19th free (and, in fact, it has been proposed to use such a procentury. The "plastering" process, i.e., the addition of cess commercially, viz., by roasting salt with iron pyrites). sulphate of lime to the grapes-an operation practised for At this stage, then, the reaction going on in the fire will some mysterious reason upon all sherries-he holds up in be expressed by the equationits true light as utterly destructive of all real vinous 4NaCl+2FeS+01=2Na2SO4+ Fe2O3+Cl4. flavour. How any man can drink a liquid containing more than an ounce of an alkaline sulphate per gallon,

Simultaneously with this the carbon of the coal comes how he can call the mixture wine and profess he likes it, into play, reducing the sulphate to sulphide, with evoluare to us mysteries inscrutable. Would it not be better tion of carbonic oxideto send us the wines pure and allow those consumers who

Na2SO4+C4=Na2S+4CO. admire the flavour of “ Epsoms” or “Glaubers to add

Of course were any substance present answering to the these delicious ingredients to their own liking: While limestone used in practice-as might happen in the ashMr. Denman, however, denounces “plaster," he is no we should have the full conversion to "black-ash," with friend to the recently patented deplastering process. It is further evolution of carbonic oxideno doubt possible to ascertain by careful analysis the exact quantity of sulphate of potash present in sherry, and

6Na2S+8CaCO3+Cz=6Na2CO3+6CaS +2Ca0+4CO. to add tartrate of baryta till all the sulphuric acid is pre- I need not say that carbonic oxide burns with a violetcipitated. But suppose that by some inadvertence a blue flame, perfe&ly indistinguishable from that produced slight excess of baryta remained in the solution! The by throwing salt into a bituminous coal fire. This may be

Sept. 1, 1876.)
Blowpipe with Spectroscope for Mineralogists.

91 proved at once by experimenting on a fire of anthracite, through the necessary changes. Moreover, the slightest which itself usually only gives out the lambent blue flame trace of salt in such a mixture gave the yellow colour in or Co. The presence of salt makes no difference what the naked flame, while the mixtures used in the crucibles ever in the colour of this flame, and it is difficult indeed contained fully 15 per cent of salt, so that the supposition to determine whether the salt is ignited at all. The dif. as to the effect of difference of temperature seems plausible. ference in the two cases is just this:-A bituminous coal -I am, &c., fire has usually a large bright or smoky flame: salt

EDWARD T. HARDMAN. thrown on it causes its size and brightness to diminish by

H.M. Geological Survey of Ireland. robbing it of the free carbon or hydrocarbon—which gives Kilkenny, Aug. 25, 1876. it those qualities, and which is derived from the volatile matter-as in the reactions stated above, carbonic oxide

BLOWPIPE WITH SPECTROSCOPE FOR resulting. But when anthracite is burned free carbon is absent, but carbonic oxide is formed; so that no altera

MINERALOGISTS. tion in colour is discernible. It is possible that the heat, instead of volatilising the sodium compound, and so

To the Editor of the Chemical News. giving the yellow flame, is entirely occupied in effecting Sir,—I enclose a sketch of an upright blowpipe with the chemical changes.

spectroscope adapted to its little lamp, the whole very With a spirit lamp or a Bunsen burner there is no free portable. My object is discrimination in travelling between carbon, nor is there any iron pyrites to react on the salt, potass and soda and many other minerals. With hammer, consequently the complicated processes just sketched out chisel, lens, bottle of acid, magnetic penknife, and a little cannot go on, and the flame only exhibits the sodium patience one can be far more independent of a laboratory colouration.

than might be imagined. It is far more interesting to be Dr. Schuster, in the note above mentioned, referred to a able to determine a mineral on the spot, more especially letter published by Dr. Gladstone in the Phil. Mag. (vol. as regards petrology, than to have to collect extensively xxiv., p. 417), giving a sketch of the similar behaviour of and defer examination except with the blowpipe, which, as certain chlorides in imparting a blue colour to fames of every one has to his aggravation experienced, leaves one various kinds. I find that in this paper the violet colour given by the chlorides of sodium, of potassium, and of barium to the flame of red-hot coals is noticed. Dr. Glad. stone says, however, that “ a doubt must rest on such observations made with a common coal fire, as it is quite conceivable that these chlorides may give up their chlorine to the alkalies or the earths of the ash.”

It struck me that it would have some bearing on the matter to ascertain whether other salts of sodium exhibited the same property of tinging the Aame blue, and I find that in these is no difference.

A little pure carbonate or sulphate of sodium thrown upon a common coal fire gives exactly the same blue colour as the chloride does; thrown on an anthracite fire they do not alter its bluish flame. Both give the intense yellow flame in the Bunsen burner.

It is clear, therefore, that the blue flame given by common salt cannot be ascribed to a property inherent to chlorides alone, and the solution I have given seems to be the most likely one. Of course the carbonate and the sulphate will give rise to much the same reactions as those sadly in the lurch when one gets amongst impure alkalies stated above. The following laboratory experiments were made with baryta and strontia in arragonite, which blowpipe solus

and alkaline earths. As an instance I have detected both a view to check the above conclusions :

failed to show me.-I am, &c., (1.) A small porcelain crucible was half filled with com

MARSHALL HALL. mon salt, placed in a jacket, and exposed over a Scientific Club, August 5, 1876. Bunsen burner. The fame appearing above the

crucible was coloured intensely yellow. (2.) The same quantity of salt, mixed with powdered charcoal, was placed in the crucible.


In this case the flame had hardly any yellow colour, and the edges occasionally appeared blue, the Bunsen

To the Editor of the Chemical News. flame being able to assert itself. The diminution Sir,—The manual of Prof. Tilden excels in the intelligent

of the yellow colouration was very marked. and thoughtful character of the exercises, but I must con(3.) The crucible was filled with salt and powdered fess to have failed in the following case, and perhaps some

charcoal, together with a little sulphide of iron better informed student may help me in the matter :-
(the substance used for the preparation of sul- J. (No. 35, p. 276.) “The analysis of barium diaceto.
phuretted hydrogen), and exposed over the Bun- tartrate gave the following results :-
sen burner as before. The yellow colouration
was almost entirely absent, while the blue flame

Oʻ2065 grm. gave oʻ1297 grm. of BaSO4.
became very distinct.

0-1377 grm. gave oʻ1307 of CO2, and o'0300 of H20. No difference could be observed in these experiments, I do not see how this data can furnish the amount of 0.

What is the formula of the salt and corresponding acid ?" whether the air was turned on or off. When these mixtures were exposed in the naked flame

I venture to add some other questions, which cannot on platinum wire they only gave the intense sodium colour, well be solved without some approximative grasp of the This is doubtless to be ascribed to the stronger heat generic nature of the reactions involved; hence it is that volatilising same of the salt before it had time to pass they have more than a mere numerical interest


IÍ. M. Grimaux has synthesised the following ureides. * Every cook knows that throwing salt on a fire "clears

What are the types and genetic equations (without further renders it smokeless.

data) ?

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