Obrazy na stronie


name acid becomes incorrect if it implies any peculiarity accepting Mr. Foster's challenge to show where Gerhardt of constitution, and superfluous if it does not." Now, imposed it. If Mr. Foster were to deny my statement as Laurent and Gerhardt did admit and assert that the that the anhydrous bases are un provided by Gerhardt salts of hydrogen are constituted like the salts of any with a name corresponding to that of anhydride for the other metal, and as Mr. Foster is doubtless perfectly acids, I might probably beg the favour of his quoting aware that they did so, the above sentence is a distinct chapter and verse in support of his denial. But as condemnation of Gerhardt's proposal of applying the matters now stand, the two great classes of chemical word acid to salts with hydrogen as base. And coupled compounds are called acids (such as CO2, 90,, SiO,, &c.) as it is with Mr. Foster's admission that these hydrogen and bases (such as K,O, CaO, Fe,(,, &c.), Whoever salts ought, in systematic language, to be called hydric wants to take their names from them for the use of their sulphate, hydric nitrate, &c., it does convey Mr. Foster's hydrates must at least give them new names which will assent in a very full manner to the principle of the pro- do as well. And he will certainly not be permitted to rosal which I made on the subject of nomenclature. take the names from the two classes of bodies, and put

The general form of Mr. Foster's paper is, however, them off with one name between them. Gerhardt seems that of an argument against my proposal; and the paper to have thought that he would be permitted to do so, contains some statements to which my silence would but the single substitute (anhydride) which he offered is probably seem to give a consent which I really cannot admitted to be not only insufficient but absolutely ungive. It must have been from inadvertence that Mr. acceptable. Foster speaks of my wishing to apply the name acid to Perhaps the most important advantage which chemists such bodies as CO2, SO,, SiO2, &c.; for I merely re- | have gained by representing all substances of known marked that the name that belongs to them is wanted composition by typical formulæ, has been the increased by its owners, and that it does not suit the hydrogen clearness with which they have been able to compare the salts to which Gerhardt wanted to transfer it.

properties of bodies with one another, without the mind Mr. Foster goes into an elaborate exposition of what being encumbered by conventional differences of form. he conceives to be the original meaning of the word Even elements are now for the most part represented by acid, and speaks of that "original meaning" as "any- formulæ analogous to those used in representing comthing but particularly clear." He might safely have pounds; free hydrogen being HH like HÌCI, free oxygen called it “ particularly cloudy.”

being 00 like Cao, free phosphorus being P,P like Every chemist knows that the great Berzelius epito- HN, &c. The one great difference which stands forth mised the prevailing definition by saying that an acid above all other chemical differences, is that which is is an electro-negative oxide, and a base is an electro-described in various terms, all more or less similar in positive oxide. No definition is complete and perfect; import to acid or acid-like and basic or base-like. We but this definition is certainly clear, and it does point have long since admitted that this fundamental differto differences of properties among chemical compounds ence is a difference in the degree in which various which are the most characteristic and important known substances exert analogous effects, a weak acid acting to us. I cannot see any chance whatever of the words like a base under the influence of a very strong acid, acid and base being given up; for they describe con- and a weak base acting like an acid to a very strong veniently the chief differences of properties by which base. Among simple and well-known compounds this we classify compounds chemically. Mr. Foster's remark, difference is most markedly represented by oxides such that “the strictly scientific significance of the word acid as SO,, P,05, SO2, CO,, CaO, K,O, PbO, Bi,O,, &c.; and has passed away,” and that the word indicates "a distinc-every chemist knows that compounds of the former class tion to which we now know that no real difference corre-are electro-negative to those of the latter class, electrosponds," must be taken as referring to Gerhardt's misuse negative oxides being called acids, and electro-positive of the word acid, as describing salts with basic hydrogen. oxides being called bases. It is admitted that hydrogen He might have gone a step further in condemnation of salts must be represented and named like other salts ; that misuse of the word, and have shown that the word hydric nitrate, or hydric phosphate, like potassic nitrate acid never has had any scientific significance as applied or potassic phosphate, and potassic hydrate or calcic to hydrogen salts.

hydrate like potassic nitrate or calcic nitrate; and GerMr. Foster quotes from my note (but apparently mis- hardt's attempt to apply to bodies of the first class the understands) the statement, “In fact, he (Gerhardt) sys- name acid is, in the words of Mr. Foster "incorrect if it tematically applied the term acid to hydrogen salts, implies any peculiarity of constitution [different from giving the name anhydride to acids, and leaving bases, other salts], and superfluous if it does not." Mr. Foster however anhydrous they might be, entirely unprovided might, however, as above remarked, have added that with a corresponding name." If bodies such as HNO,, Gerhardt's definition of the word acid is simply in itself H,SO4, H,PO, were considered to be entitled to the devoid of meaning. He quotes it thus :- Acids are “salts name “ acid,” then for precisely similar reasons, bodies whose base (the italics are mine] is wholly composed of such as KOH, Ba(OH), would be entitled to the name hydrogen.” A person ignorant of the meaning of the “ base;" and if the bodies N,O, SO, P,0%, &c. formed words acid and base could surely not ascertain from his by dehydrating these so-called acids are called “ anhs- inner consciousness which is the acid and which the drides,' then some corresponding and distinctive name basic constituent in any of the following compounds :should be given to the bodies K,O, Ba(, &c., formed KOH, HNO,, BaO, H, SO,H,; and Gerhardt's pretended by dehydrating the so-called bases. The absence of any definition would afford him no aid in ascertaining which such term is a deficiency sufficiently grave to make one of these compounds are to be called acids, which bases, pause in adopting the term anhydride in systematic One is almost tempted to suspect Mr. Foster of bitter language, until the idea which it represents is duly irony when he calls this definition "strictly scientific applied to the other great class of chemical compounds; and logical.” Although different in form, it is not one but I cannot, with Mr. Foster, call it a “ limitation;" bit more reasonable than the Munchausen (or Irish ?) and as I have not said that Gerhardt imposed any feat of ascending to the moon by the aid of a mile-long “ limitation ” in the matter, I may fairly be excused from chain, the traveller first fastening his chain by one end


at a point one mile up, then climbing up by the chain to Many of these processes are known to consist of a that point, and so on. But I am sorry to say that Ger- series of double decompositions, and the fact is often hardt's disciple is even in a worse plight than the aêro- mentioned in alluding to them; but it does not seem naut, he is so unfortunately circumstanced that even if likely that we should abandon the use of the terms comhis chain were fastened one mile up, he could not climb bination and decomposition. up it. For if, as a preliminary to the understanding of Mr. Foster has discussed in his paper what he calls Gerhardt's dictum, we are told how to find out which is the original use of the words acid and base, which is the acid and which the basic constituent of a given com- sufficiently characterised by his own words, “anything pound, we find that this preliminary information is but particularly clear." He has also discussed Gerhardi's inconsistent with Gerhardt's dictum, and prevents our misuse of the word acid. His conclusion that the word making any use of it. By the aid of a battery anybody had better be given up, would be quite worthy of serious could find out which are electro-negative, which the consideration if the words were only used in those imelectro-positive oxides derivable from the above com- proper senses. But the words acid and base really mean pounds; but Gerhardt would then reject the result as something not only true, but of fundamental importance, inapplicable to his purpose.

which we are constantly obliged to consider and speak It has always seemed to me that the most plausible of in chemistry; and I am quite sure that it would be utterly objection to the use of the terms acid and base in the beyond my power to take from them their established sense of electro-negative oxide and electro-positive oxide meaning, even if I wished to do so. There is at present was the fact that some acids, such as so, P,05, SiO,,, a considerable amount of inconsistency in the prevailing &c., may be put in contact with bases such as BaO, K,0, use of these, as of most other scientific terms; and Mr. &c., without manifesting any strong tendency to combine Foster's interesting paper affords further arguments than with them; and observations of this kind led some che- those which I had given in favour of abandoning as mists to say that, in their chemical properties, these so- speedily as practicable the misuse of the terms which called acids do not behave like acids, and that it is there has crept into partial use through popular disregard of fore reasonable to deprive them of the name acid. Now water in hydric sulphate, and which Gerhardt unsucthe fact is that these acids always do combine with bases cessfully endeavoured to incorporate with scientific when brought in contact with them in the fluid state, language. and they combine with more force than that with which I have not discussed the proposal to call both acids their hydrates react on basic hydrates. It is well known and bases oxides, because it has not as yet received suffithat when two saline molecules such as SO,H, and cient development to enable me to form any opinion upon BaO,H, react on one another with liberation of water it beyond the obvious objections which present themand formation of a salt, the force of combination, as selves at first sight to so grave a change. Thus, MnO, measured by the heat evolved, is less than that which Mn,O., MnO2, MnO,, Mn,O, are at present conveniently the acid and base exert in direct combination ; for the distinguished by names, calling the last two acids, and process of double decomposition separates the water from the first two oxides; and so also CO and Co, are very SO, and from Bao, and in doing so absorbs just as much conveniently distinguished by the words oxide and acid. heat as was evolved when water combined with SO, and Another circumstance which would alone have been BaO; so that the force with which the two hydrates re. sufficient to prevent my offering any opinion on this proact on one another is by so much less than that with posal is the fact above explained, that it is founded on which SO, combines with Bao.

Mr. Foster's opinion that the word acid is not clear, and Mr. Foster expresses an objection to applying the is unworthy of being retained.-Philosophical Magazine term "combination " to the reaction of such bodies as for June, 1865 anhydrous acetic acid (C2H,0),0 on water, because by a University College, London, May 16, 1865. process of double decomposition the two molecules, acid) = and water, give rise to the formation of two new mole

TECHNICAL CHEMISTRY. cules; but if his objection is admitted to have weight, it applies equally to the reaction of free chlorine on free hydrogen, where two molecules of the elements form

On the Electro. Chemical Preparation of Metalloids. two molecules of the compound by a process of double PURPOSING to speak only of unpublished methods, we decomposition. If such reactions as that of chlorine on need not now speak of ozone. Several distinguished hydrogen, and of anhydrous acetic acid on water, are chemists are actually endeavouring to find some relation not combinations, the word might perhaps be retained between the state of the atmosphere and the quantity of for such reactions as the combination of carbonic oxide ozone present in it. We have never been able to admit and chlorine; or SO, and water, where two molecules the presence of free ozone in the air. How should unite to form one ; but if Mr. Foster seriously proposes oxygen, which, when electrified, attacks the metals, and such a restriction of the word, it will be time enough to all matters in the least oxidisable, respect nitrogen, consider it. The present usage is to describe as combi- water vapour, organic substances in a word, all that nations those reactions in which the resulting molecules the air contains ? This question will not, however, be are less various than the original molecules, as in the definitively settled until a sufficiently certain and special cases of

reagent for ozone be found. 0,+ (H)2 = (H,0);; C1, + K, = (CIK);

Électro-chemistry is now a complete science; for all 1,0,+H,O=(NO,H)2 ; (C,H,O),0 + H,O=(C,H,O,),, &c. simple bodies, and for the greater number of their and, in like manner, to describe as decompositions those principal compounds, it gives a mode of preparation reactions in which the products are more various than which, under m

e various than / which, under most circumstances, is even preferable to the materials, as

that offered by pure chemistry. We will first pass in SO,H, = SO, + H,0; Pb(NO)2 = PbO + 0 +1,04;

review the metalloids whose preparation by this means (CH,KO) = C,H,O+co,KG (go), = 2Hg + 0,

is most worthy of interest.
Nitrogen must thus be isolated in a pure state-it

* Cosmos, 2nd series, i , 595.

(CH:+s0,H. = ($8,0 +1,0 +0,H..

must, in fact, be extracted from ammonia or nitric acid ; a bent glass tube filled with clay, moistened with a solu. now in either case it undergoes a secondary action, tion of nitrate of potash ; and on the other with a resulting from the decomposition of water.

metallic arch of copper and lead, the copper being Chlorine, bromine, and iodine are easily obtained by plunged into the sulphate of copper, and the lead into following the same method.

the sulpho-carbonate. The current thus engendered is The process consists in decomposing in a U-shaped sufficiently energetic to decompose the sulphate of copper: tube the hydrogenated combination of the metalloids, secondary reactions, which it would be useless to analyse. using graphite conductors as the electrodes; the orifices are produced, and the sulphur of the sulpho-carbonate of the tube communicate with washing flasks, and hence of potash, partly isolated, is deposited in the form of the purified gases pass into the receivers. By operating octahedra, with rhomboidal bases on the lead plate. By on hydrochloric acid, chlorine is disengaged from the making electricity act on hydrosulphuric acid, M. positive pole in a state of absolute purity; it is the same Berthelot found that sulphur deposited at the positive when acting on a fused alkaline earthy chloride. pole did not assume this form. Electricity may then be

Bromine is a liquid which is a bad conductor of elec- employed, provided it is properly applied, in studying 'tricity ; its electro-chemical treatment requires, then, the molecular constitution of polymorphous bodies, in that it should be maintained in solution in water ; if not, their various combinations. Only it is necessary that it becomes necessary to use a great number of voltaic the intensity of the electric force should be in proportion couples. As for iodine, we know how easily iodised to the affinity causing the combination. compounds decompose under the influence of the weakest It is difficult to obtain tellurium in a compact mass electric current ; however, to collect the iodine at the by the electro-chemical method; Ritter could oply positive pole, it must be dissolved as it decomposes, for extract it from a saline solution in a pulverulent state. its crystals, fixed on the electrode, will oppose the Arsenic is of all metalloids most easily isolated by passage of the current. If electricity has hitherto electricity, for it is almost as good a conductor as a metal. remained powerless to isolate fluorine, it is because By means of an apparatus (known as simple in electrophysicists and chemists have been unable to find the chemistry), all the metalloid they contain may very relation existing between the constitution of fuorides rapidly be extracted from arseniferous substances. Place and the electric force to be put in play. If chemical a solution of arsenical matter in a platinum vessel, plunge affinity is conquered by electricity, in the generality a zinc wire into the liquid, and the arsenic will appear of compound bodies, no exception can exist. Only we on the platinum; by prolonging the action the whole of must know how to apply this antagonistic force of the arsenic is extracted from its compound. This method affinity, and especially to oppose secondary reactions ; it may be varied in different ways, and renders valuable is effects of this kind which hare prevented M. Bec- service in medico-legal researches; it is much superior in querel's collecting fluorine. The isolation of this metal- sensibility to the process actually in use. Toid is considered almost impossible, because of its affinity Boron has not yet been obtained on the electrode; for hydrogen and chlorine; M. Becquerel has, however, however, it has been electro-chemically isolated by Davy. succeeded in separating it from one of its metallic com- "When boracic acid," he says, " is exposed between two binations in the following manner :-He placed on a surfaces of platinum, receiving, at the same time, all the receiver a small platinum spiral, terminating in a point, action of five hundred pairs, an olive brown matter is and on which were deposited fragments of fluoride of formed on the negative surface, gradually increasing in calcium; the two ends communicated with two platinum thickness, and finally becoming black. Insoluble in wires, larger in diameter than that of the spiral, passing water, but soluble, with effervescence, in nitric acid. through two openings made in the sides of a receiver ; | Heated to redness on platinum, it burns slowly, producthese wires were connected with a Wollaston's pile coming a white vapour, which reddens litmus paper." posed of twelve elements (this kind of pile gives, as is The isolated body is therefore boron, which oxidises well known, a current rery powerful in intensity and in immediately, and the electric action should cease as soon quantity). The receiver being placed on the plate of as the platinum is covered, this metalloid being an ex. the air-pump, and the air dried, a vacuum was formed; tremely bad conductor. then the electricity was called into action. The incand- Silicium is, with respect to conductibility, analogous escence of the spiral was very vivid for several seconds; to boron. Davy was unable to isolate it, even by a pile the current was interrupted, and the air allowed to enter, formed of a very large number of elements. M. Becquerel when the fluoride of calcium was found partly decom- kas obtained crystals of silicium by combining phy, posed; it reddened turmeric paper, and the surface of sical and chemical forces he took two tubes of three the platinum was found covered with a greyish pellicle, to four millimetres in diameter and one decimetre seeming to indicate the action of fluorine. From this long; one end of each tube was filled with clay moistened experiment it would appear possible to isolate fluorine. with salt water. By this end the tubes were plunged Induction currents might perhaps bo employed with into a vessel also containing salt water; into one was success, for it seems necessary for the decomposition of poured a saturated solution of gelatinous silica, in any kind of fluoride, to develope electricity more especially hydrochloric acid, and in the other a saturated soluof tension than of quantity.

tion of chloride of sodium; a zinc wire was plunged The electro-chemical separation of sulphur is certainly into the latter, and a platinum wire into the former not of importance for industrial chemists, but it is for communication being established between these two those studying the different physical states which may wires, an electric current was produced, the hydrobe assumed by this body in its combinations ; from this chloric acid decomposed, and the nascent hydrogen repoint of view the following experiment is very inter- duced the silica; crystals of silicium appeared on the esting :

platinum, and remained so long as the current passed ; Into a glass vessel pour a solution of sulphate of they redissolved when it was interrupted. copper, into another an alcoholic solution of sulpho- To preserve them they must be rapidly removed, carbonate of potash; then establish a communication washed, and then dried in a vacuum, and kept in a tube between the two liquids-on the one hand, by means of with potassium.


DUBLIN INTERNATIONAL EXHIBITION. prejudice in favour of glass, they have unanimously By CHAS. R. C. TICHBORNE, F.C.S., F.R.G.S.I., 8c. reported in favour of platinum system... We should (Continued from vol. xi., page 295.)

be sorry for an erroneous opinion to be promulgated on PLATINUM v. GLASS.

this subject, although this may he considered rather SINCE our report upon the case shown by Messrs. John

an interested statement on our part.- We are, dear son and Matthey, we have received a letter from that firm / Sir. yours very faithfully, JOHNSON, MATTHEY, AND Co. in which they repudiate the idea that the manufacturers -C. Tichborne, Esq., Dublin.” are returning back to the glass. We are very glad to learn this, as no doubt can be entertained of the superiority of

Scientific Instruments (Continued).— The following the metal in many respects. The writer is also in anrms show nne specimens of scientiac inst!

Calenina firms show fine specimens of scientific instruments, but degree pleased that he has been the means of bringing principally cameras, microscopes, surveyors' instruments, forward a contradiction to statements and impressions

and barometers :--Mr. S. Yeates, Dablin; J. H. Dallwhich had certainly taken hold of the chemical public.

meyer, London ; Crouch, Bros., of London, who also show The author is not a manufacturer of sulphuric acid

some very fine microscopic photographs of a considerhimself, and therefore can only judge of the facts that

able size. More is frequently to be gained from the come within his observation. We have the following

study of these photographs than by ocular examination passages occurring in the most important chemical

of the object when in the microscope. H. Webb, of report ever published, the said report being written

Birmingham, shows what appears to be a very fine col. upon the largest exhibition ever held in Europe:

lection of microscopic objects, as far as an opinion can “Nevertheless the platinum alembics have disappeared

be given without an examination under the instrument. from many of the British sulphuric acid works, and the

Field and Sons, Birmingham, exhibit their wonderfully manufacturers are returning to the old method of eva

cheap microscopes porating in glass." Again, “ In Lancashire the use of

John Young, of Dalkeith, shows moulded carbon for platinum retorts has been entirely abandoned.” These

ca electric batteries. This gentleman first undertook the facts in connexion with a visit made by the author to

task of making a series of experiments in connection one of the largest manufacturers in the kingdom (not

with the above subject at the request of several gentlein Lancashire), who had also given them up, were quite

men interested in the progress of electrical science. The sufficient to justify his remarks. Against them we have

carbonaceous material (coal, &c.) is ground to a very a case where a manufacturer has returned a second time

fine powder, moistened, and moulded into the form to the platinum. There can be no doubt that where the

wished, in a similar manner to the making of bricks. advantages and disadvantages are anything like equally

The forms so moulded are then slowly dried, and, when balanced, fashion creeps in even in hard matter-of-fact

dry, packed into iron moulds, and subjected to a bright practical processes, and this may account why, in Messrs.

| heat in a close oven. The effect of the heat is to drive off Johnson and Matthey's opinion, a retrograde movement

the whole of the bituminous matter, leaving a dense and has taken place to a certain extent; and we are inclined

compact coke in the moulds. The pieces are then boiled to think with them that it is a retrogade movement. Of

in pitch, and again charred along with a charge of coal so much importance does the author consider the ship in a gas retort. This is repeated several times, until the (for sulphuric acid may be viewed as the progenitor of

required density is attained. They are then ground into chemical products), that, having received Messrs. Johnson

the proper shape, and smoothed on the surfaces. They and Matthey's permission, a few extracts from their note

are then kept for twelve hours in a gas relort, along are given :

with coal, the latter being used to produce carbonaceous "We would, however, ask you to modify your views

vapour, which saturates and closes the pores in the coke. as regards the platinum system for concentrating sul

When the process is properly conducted, the carbons are phuric acid, a-suring you that the statements made

taken out, possessing a close metallic steel-grey surface. are essentially contrars to fact. We have never for forty They are much more porous than retort carbon, by which Tears past been so much engaged in the manufacturing they acquire high electro negative qualities. of platinum boilers as we have been lately. This is! We must not forget to notice the patent flexible practically the strongest evidence of the advantage of diaphragms for covering the surface of liquids which the platinum over the glass system. . . At the pre: would be affected by the atmospheric oxygen. This sent moment we can instance a manufacturer who patent includes vessels wholly lined with sheet indiaoriginally worked with platinum, and was induced to give

rubber, or having a diaphragm which flvats loosely upon it up in favour of glass, and after incurring the expense the surface of the liquid. The liquid is hermetically of the sacrifice of the platinum plant, and that of setting sealed to the extent of the non-porosity of india-rubber, up the numerous furnaces required for glass working. but we believe that this substance is still capable of has lately taken down the whole of the latter, and is again allowing the diffusion of gases to a limited degree. using the platinum, assuring us that the saving in fuel The following few articles that we are about to notice alone very greatly exceeds the interest, &c., of the cannot be classed as scientific instruments, but still platinum plant. . . We can go further than this, and possess such interest in a technical point of view that state upon well-proved statistics that the saving in fuel the present article would hardly be complete without and working expenses and space, will in five years pay touching upon them. One of them is Messrs. Morton's in full for the cost of platinum vessels; after which time patent refrigerator. This arrangement may be viewed not only is there the extreme profit over the glass sys as a worm, except that the wort or liquids to be cooled tem, but an intrinsic value in the plant. Also there is are made to traverse the exterior of the metallic tubes, in the advantage of great rapidity and certainty in work- which is circulating the cooling medium. This apparatus ing, and above all, of absolute safety to the workman consists of a series of flattened tubes made of strong emplosed... It may interest you to know that a copper (tinned), and connected at the ends alternately committee of the directors of some of the Continental by the caps, so as to admit of a continuous flow of cold manufactories lately visited England for the express water inside the tubes. The whole is fixed to a copper purpose of reporting upon the two systems, and after a case, and secured in a strong wood frame. The worts thorough investigation, although they came with a strong are admitted at the other end, and flow in an opposite


direction to the water alternately under and over the

PROCEEDINGS OF SOCIETIES. tubes, this motion being produced by the longitudinal ribs on the top and the corrugated bottom. The absolute necessity for the rapid cooling of worts, says the circular, | ON THE PRESENT STATE OF THE CHEMISTRY is now fully recognised by all brewers who have made

OF GAS LIGHTING. the chemical laws which govern vinous fermentation

By Henry LETHEBY, Esq., M.B., &c. their study.

Delivered at Birmingham, before the Society of Gas The applications of graphite-or black lead, as it is

Engineers. sometimes called-have become more numerous of late ; GENTLEMEN, - I propose that we should continue tothus it is extensively used for electric purposes, the night our inquiries into the chemistry of gas lightingglazing of gunpowder and shot, black lead pencils, and that, in fact, we should extend our investigation into the last, but not least, the making of plumbago crucibles. subject which was commenced at the meetings of this

The Patent Plumbago Crucible Company exhibit spe Association last year at Manchester, when, as some of you cimens of their crucibles, so well known to metallurgists. will remember, I directed your attention to the chemical Mr. Brodie's well-known and beautiful process of disin

principles involved in the manufacture and purification tegrating graphite has enabled the most inferior qualities

of coal gas. On the present occasion we will examine the of that mineral to be made available. The Plumbago

leading physical, chemical, and photometrical properties Crucible Company, however, purify their graphite by

of the most important constituents of coal gas.

Briefly to recapitulate the subjects of the last lecture, passing chlorine through it when heated to redness,

I may remind you that we inquired, in the first place, into or in some cases simply by separating the iron, which

the composition and probable origin of the material out of is the great impurity, by magnets. The graphite so

which gas is produced - coal; that we then examined the prepared answers their purpose as well as Mr. Brodie's, leading constituents of the several varieties of coal which and is less expensive.

are best suited for the manufacture of gas, especially It is stated that a large deposit of graphite has re- directing attention to the form in which the most objeccently been discovered by an enterprising Frenchman, tionable impurity (sulphur) of coal existed. We also M. Alibert, in the Batougal Mountains of South considered the phenomena of carbonisation or distillation Siberia. It may be mentioned that the higher class of coal, and saw how much it was influenced by temperagraphite in this deposit is accompanied by an inferior ture, and how, under the influence of heat, the elements variety which, as it appears from experiments made | moved from their old states of combination into new. by Mr. Valentine, can be easily purified. The Siberian

We then discussed the composition of raw gas as it

| leaves the retort, and I pointed out to you that it consists plumbago is not much used at present by the Plumbago Crucible Company, as it contains too much iron, and

of the constituents marked in the following table :although this could be entirely removed by the com

Constituents of Raw Gas. pany's patent process, it is found cheaper to work

Tar matter.

Aqueous vapour. with Ceylon plumbago, which contains but little iron.

Carbonic acid. The graphite used by them contains 98 per cent of pure

Ammonia. carbon. The company exhibit Ceylon, Siberian, and

Cyanogen. other graphites in their case.

Sulpho-cyanogen. To show the importance of this branch of manufac

Sulphuretted hydrogen. ture the following facts may be cited :—The consumption

Bisulphide of carbon. of Ceylon graphite at the Battersea Works has had an

Sulpho-hydrocarbons. extraordinary effect upon the price of the article. When

Nitrogen. the company commenced business it cost about 10l. per

Oxygen. ton, but now it cannot be bought at double that price. In Ceylon applications to dig graphite are daily on the

Hydrogen. increase, notwithstanding the rate of 148. per ton which

Light carburetted hydrogen. has to be paid as royalty at the Colombo Cutcherry.

Carbonic oxide. The following figures, giving the amount of revenue col

Condensable hydrocarbons. lected at Colombo and Galle, on account of royalty, in

Now the whole of these constituents above the line may 1862 and 1863, clearly show the extraordinary increase

be regarded as impurities, and I pointed out to you that

the taking of these impurities out of coal gas, in order to in demand for Ceylon graphite :

effect the perfect removal of them, involved a proper order, Increase in 1863 from 1862. Westei n Province . . . 8ool.

as it were, of purification-that, in the first place, both Southern Province.

science and practice pointed to the fact that the conden. . 1701.

sation or cooling of the gas should not be too sudden ; The total quantity of graphite exported from Ceylon that the longer the gas was kept in contact with tar and in 1862 was 40,195 cwt., of which no less than 34,730 ammoniacal liquor before it went to the condensers the cwt. was shipped to Great Britain. The Patent Plum- | better. It had been seen in numerous instances that a bago Company are the principal consumers of the latter. long hydraulic main, extending a considerable distance M. Dierick writes* the following of these crucibles :

from the retorts, always effected the condensation of " Each crucible runs from forty to sixty pourings, and naphthaline as well as objectionable sulphur compounds; can with safety be dipped in cold water when at a red

and I further pointed to the fact that when the gas had heat, and used again immediately as if it had not under

traversed the condensers it was never fairly purified if it gone any change of temperature; the metal is also

left them at a higher temperature than 60° Fahr. The fused much more rapidly, saving time, fuel, labour, and

aim, in fact, should be slow but complete condensation by

gradual cooling, for if the temperature of the gas exwaste. The saving of metal is also very great, as to each

ceeded 60° the ammoniacal liquor was never of its full worn crucible there adheres a certain amount of metal ;

strength, and much sulphur, ammonia, carbonic acid, and the commoner the crucible, the greater the absorption

aqueous vapour passed on to the purifiers, where such and adhesion."

impurities were seriously in the way. * M. Dierick, Master of the French Miut.

The next question is how to remove from the gas the

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