Obrazy na stronie

Oct. 20, 1865.
Royal Institution of Great Britain.

187 cated whiskee," "pure Islay mountain," " Indian tinc a molecule involves the liberation of two attraction units. ture," and "red currant cough elixir," the exciting The saturation of these two units by the trivalent nitrogen principle of all of which was found to be hyponitrous atom left 3 --2=1 attraction unit disengaged ; in a similar ether prepared from methylated spirit. The above com- manner, if the saturation be effected by the quadrivalent pounds were all highly stimulating, and it would appear carbon atom, 4–2 = 2 attraction units must remain unthat they are consumed by some of the poor, because saturated. they produce intoxication at the cost of only a few

The reason why the carbon atom, when fixed by com

pence, whilst there are good reasons for believing that hypo- pounds, associates with two atoms of hydrogen, --why so nitrous ether itself, and in some parts of Ireland eren large a number of carbon compounds differ by CH,, or a sulphuric ether, are used by the needy classes for the of numerous series of carbon compounds which is desig.

multiple thereof,- in fact, the relation in the composition same ohject. It is difficult to see how this evil, so per- nated by the term homology is now intelligible. nicious to the moral and physical welfare of those who

In attempting to illustrate this behaviour of the carbon indulge in it, can be checked, as the substances under atom by our mechanical models, we conveniently select consideratinn possess more the character of medicines the molecule of marsh gas, the simplest compound of than of ordinary spirits, and may thus be legally kept carbon and hydrogen, as the foundation of our edifice. and sold by any chemist.

This molecule we open for the insertion of a second carbon During the year 139 samples of wood, spirit were atom. The two attraction units liberated by the rupture examined, the object being to ascertain that they were of the molecule are saturated by two of the attraction free from vinous alcohol, and suitable for methylating units of the quadrivalent carbon atom, two attraction spirits of wine.

units of which remain unsaturated. Indeed, two carbon Miscellaneous Samples. – Under this head 217 atoms of hydrogen. The transformation of marsh gas into

arms remain uncovered, on which we forth with fasten two samples have been analysed, including spirits, wines, hydride of ethyl is thus accomplished. cherry and raspberry brandies, medicated compounds, cane and starch sugars, molasses, treacle, methylated spirits, “Finish,” vinegar, chocolate, cocoa, caramel, and cyder. Total Number of Samples Analysed in the Laboratory in each of the Years 1862, 1863, and 1864.

H Number of Samples examined in Description of Samples.


1864. Tobacco


158 Snuff

34 57 Tobacco exported on drawback

1765 1746 Snuff exported on drawback,

354 260 Pepper

30 13 Beer, and substances used in its adulteration.


31 Tea

3 Coffee


61 Malt

327 388

394 Beer (original gravities)


6571 Distillers' wash


5 32 Wood spirit :


139 Malt for cattle feeding .

We open again for the reception of another atom of 884

carbon, and this third atom joins under exactly the same Wines (Customs).

182 Miscellaneous samples

circumstances, carrying along with it into the new mole175

217 cule the spaces, so to speak, for two additional atoms of

hydrogen. Hydride of ethyl in this manner becomes 11,360 8588 10,708 hydride of propyl.


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Weekly Evening Meeting, Friday, April 7.
H.R.H. THE PRINCE OF WALES, Vice-Patron, in the Chair.

On the Combining Power of Atoms.
By Dr. A. W. HOFMANN, F.R S.

(Continried from page 179.)
TIB experience acquired in the study of the oxygen and
nitrogen compounds has prepared us for the examination
of the increment of carbon. In fact, it is only necessary
to apply the method hitherto followed to one of the series
of carbon compounds already reviewed to enable us to
understand why the carbon atom is assimilated, not atom
by atom, like the oxygen atom, not associated with one
atom of hydrogen like the nitrogen atom, but associated
with two atoms of hydrogen.

We have only to remember that the carbon atom saturates four combining units, while the nitrogen atom saturates only three. Now, we have seen that the rupture of HYDRIDE OF ETHYL.

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Royal Institution of Great Britain.



Oct. 20, 1865.

FIG. 17.

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Hydride of propyl, by the accession of a fourth carbon chemical edifices, it is because I want to show you that atom, is converted into hydride of butyl.

our building stones are available for many other purposes.

Hitherto we have been satisfied with examining under what conditions the atoms of oxygen, of nitrogen, and carbon are received into molecular structures. The question now presents itself, On what terms the chlorine atom is allowed to join?

The model of the marsh-gas molecule is still before us. H Let us open this molecule for the reception of a chlorine

atom. Two attraction units are thus liberated ; but the

chlorine atom is univalent. Accordingly two atoms of H II

chlorine are required, one of which combines with the

hydrogen atom which we remove from the marsh-gas, II

D converting it into hydrochloric acid which separates,

while the other chlorine atom joins the rest of the mole

cule of marsh-gas. The new molecule, monochlorinetted H

marsh-gas, may be looked upon as marsh-gas, in wbich one atom of chlorine holds the position originally occupied by the hydrogen atom. We are thus led up to the recognition of new conditions of combination-conditions which have not as yet attracted our attention this erening, but which unfold to us one of the most important principles of modern chemistry, the principle of substitution The monochlorinetted marsh-gas, which is a liquifiable gas, when again submitted to the action of chlorine loses a second, a third, and lastly, a fourih atom of hydrogen in the form of hydrochloric acid, giving rise to the formation

of dichlorinetied, trichlorinetted marsh-gas, better known as HYDRIDE OF PROPYL.

HYDRIDE OF BUTYL. chloroform, and, lastly, of tetrachlorinetted marsh-gns or

tetrachloride of carbon, i.e., marsh-gas in which the four It is scarcely necessary to expand these illustrations, atoms of hydrogen are displaced by an equal number of and if I'venture to raise up a few more of these mechanico- chlorine atoms (Fig. 18).

FIG. 18.

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MARSH-GAS. Our information regarding the combining powers of At one time the exertions of chemists were anxiously atoms is thus materially expanded. Having already learnt directed to the isolation of the atomic aggregate CHg. of that when entering into a molecular structure the carbon the radical methyl (Fig. 19), from one or other of the atom associates with two atoms of hydrogen, the atom of methylic bodies just enumerated. The facility with which nitrogen with one atom of hydrogen, that the oxygen atom the chlorine atom in chloride of methyl may be exchanged combines directly, we now find that the chlorine atom for other atoms, leaving the aggregate of carbon and combines only by substitution, i.e., when a space has hydrogen, which we call methyl, perfectly intact, the become vacant in the molecule by the expulsion of hydrogen. mobility of one of the hydrogen atoms in methylic alcohol,

The rest of the marsh-gas molecule remaining after the and of two of the hydrogen atoms in methylic ammonia, introduction of one atom of chlorine, and consisting of one the possibility of replacing even the oxygen and the atom of carbon, combined with three atoms of hydrogen, nitrogen in these compounds, without affecting the methyl, is frequently designated by the name of methyl. The the stability, lastly, of methylic marsh-gas, containing as aggregate of atoms СHz, the radical methyl, may be traced it does the whole of its carbon and the whole of its in all the compounds obtainable from marsh-gas by the hydrogen in the form of methyl, all these circumstances insertion of other aloms. Thus, by the assimilation of an appeared to indicate the probability of the separate existoxygen atom, marsh-gas becomes methylic alcohol, i.e., ence of methyl. Why all attempts to separate the atom water in which one atom of hydrogen is displaced by group CH, have remained unsuccessful; why methyl methyl, by the absorption of nitrogen with its tributary could not be caught; why, ultimately when Dr. Frank hydrogen, it becomes methylamine, i.e., ammonia in which land's masterly experiments appeared to have precluded one atom of hydrogen is displaced by methyl; by the all chance of escape, despairing methyl combined with incorporation of an atom of carbon, lastly, with its pair of itself, surrendering as methylic marsh-gas or methylhydrogen atoms, the marsh-gas molecule is converted into methyl ; why, in fact, it would appear to be an essential methyl-marsh-gas, i.e., marsh-gas in which an atom of character of methyl not to have a separate existence: all hydrogen is displaced by methyl.

these questions are readily answered by our croquet balls,

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FIG. 20.

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which exhibit us methyl as an unfinished molecule, capable of a separate existence. This question is accessible capable of conversion into the finished molecules, hydride, to experiment. Olefiant gas, indeed, possesses all the chloride, hydrate, amide and methide of methyl, but not characters which, granting for argument's sake the possicapable of existing as a molecular fragment with imper- bility of its existence, we are inclined to attribute to an fectly balanced attractions.

unfinished molecule. In the cases hitherto considered, we Taking a farewell glance at the results we have elicited saw the chlorine atom, when admitted into a molecular this evening, we may fairly ask whether the experience structure, always entering with substitution, hydrogen sepacollected on a comparatively limited area is fully and rating from the chlorinetted molecule in the form of hydrounequivocally corroborated by the examination of a more chloric acid. In this manner we succeeded in transforming expanded range of observations ? To this question we the marsh.gas molecule successively into monochlorinetted, cannot unhesitatingly give an affirmative answer. It di-, tri-, and, lastly, tetrachlorinetted marsh-gas or tetrawould not be difficult to quote a number of substances, chloride of carbon. Submitting, on the contrary, olefiant the construction of which appears to have been governed gas to the action of chlorine, we find that the chlorine is by rules of combination different from those which we fixed directly, without substitution, the chlorine atoms meet, have endeavoured to lay down. Indeed, we need not even go beyond the circumscribed field on which we have hitherto moved to meet with prominent cases of exception.

Among the several compounds of carbon and hydrogen which have passed through our hands this evening, we remember the two simplest, marsh.gas and olefiant gas.


c) In the marsh-gas molecule CH4, we have the carbon atom completely saturated with hydrogen ; by the entrance of a second carbon atom, with its two accessory hydrogen atoms, we saw the molecule of marsh-gas, or hydride of methyl, converted into the molecule of hydride of ethyl C,H.

The formula of olefiant gas, C,H,, places its molecule midway between the molecules of marsh-gas and hydride of ethyl. Comparing olefiant gas with marsh-gas, we find that it contains one of carbon more than the latter, the number of hydrogen atoms being equal in both substances. Contrary, then, to the rule on which we hitherto relied, we find that the carbon atom, transforming the marsh-gas molecule into the molecule of olefiant gas, enters without


DUTCH LIQUID. carrying along the two atoms of hydrogen, which we had accustomed ourselves to consider as the inseparable com- so to speak, with vacant spaces existing in the olefiant gas panions of the carbon atom on such occasions. While molecule ; in order to get in, they need not expel a corresfrankly admitting that in olefiant gas we meet with the ponding number of hydrogen atoms to make room for them. first exception to a rule hitherto unbroken, we are entitled The compound generated is the so-called Dutch liquid, an to inquire whether there are no means of explaining this oily substance first produced by an association of Dutch anomalous construction of the olefiant gas molecule. Let chemists at the close of the last century. It was the prous again apply to the models which, in a measure, have duction of this oily liquid that gave rise to the name of assisted us in constructing the rule; perhaps they may olefiant gas. The number of chlorine atoms thus received help us also in elucidating the exception.

directly without substitution is two, corresponding exactly In building up the molecule of olefiant gas by the inser- with the number of attraction units that remained unsatution into the marsh-gas molecule of one atom of carbon rated. Any further number of chlorine atoms are found only, we obtain what hitherto we would have called an to enter by substitution, and by substitution only. Similar unfinished molecule,-i.e., a molecule in which two of the phenomena are observed when olefiant gas is brought into attraction units of the second carbon atom are unsatisfied. the presence of bromine. We have here a large glass Indeed, a glance at our model shows us that two carbon vessel containing some bromine and water ; the vessel, by arms project uncovered. We are thus led to inquire means of a flexible tube, is connected with a gas-holder whether unfinished molecules-i.e., molecules in which a filled with olefiant gas. On agitation, we see the olefiant certain number of attraction units remain unbalanced—are gas rushing into the vessel as into a vacuum. The olefiant


190 Royal Institution of Great BritainPharmaceutical Meeting. Cameron

Oct. 20, 1865. gas fixes two atoms of bromine, being converted into a tion so kindly bestowed on my remarks will not, I trust, transparent colourless liquid, the substance called dibromide have been eniirely thrown away if I have succeeded in of olefant gas. Here, again, the combination takes place convincing you that modern chemistry is not, as it has so without substitution.

long appeared, an ever-growing accumulation of isolated The behaviour of olefiant gas, under the influence of facis, as impossible for a single intellect to co-ordinate as chlorine and bromine, elucidates the nature of its molecule. for a single memory to grasp. The facility with which this gas is capable of fixing two atoms

The intricate formulæ that hang upon these walls, and of chlorine to become Dutch liquid, two atoms of bromine the boundless variety of phenomena they illustrate, are to become bromide of olefiant gas, and by roundabout pro- beginning to be for us as a labyrinth once impassable, but cesses two atoms of hydrogen to become hydride of ethyl- to which we have at length discovered the clue. A sense all three finished molecules-characterises olefiant gas as a of mastery and power succeeds in our minds to the sort molecule interrupted in its growth, and in which the power of weary despair with which we at first contemplated their of resuming this growth, and the limit of its final develop furmidable array. For now, by the aid of a few general ment may be traced by the simplest experiments. The appa- principles, we find ourselves able to unravel the complexirently anomalous construction of the olefiant gas molecule ties of these formulæ, to marshal the compounds which is thus most satisfactorily accounted for. Indeed, far from they represent in orderly series ; nay, even to multiply disturbing the harmony of the rules of combination elicited their numbers at our will, and in a great measure to foreby our inquiries, a closer examination into the nature of cast their nature ere we have called them into existence. this compound, whilst explaining whatever appeared excep. It is the great movement of modern chemistry that we

It is a tional in its construction, leads us, on the contrary, to a have thus, for an hour, seen passing before us. loftier interpretation of these rules, to the conception of movement as of light spreading itself over a waste of compounds, the very structure of which foreshadows the obscurity, as of law diffusing order throughout a wildermore prominent features of their chemical character. ness of confusion, and there is surely in its contemplation

I have selected olefiant gas as an example of a class. something of the pleasure which attends the spectacle of We remember that this substance is the first term of a a beautiful daybreak, something of the grandeur belonging long list of homologous bodies, in all of which we find to the conception of a world created out of chaos. similar structure combined with similar chemical properties. All these substances, and, let me add, a great variety of others, we have to regard as molecules arrested under

PHARMACEUTICAL MEETING. special circumstances at a certain stage of their development,

Wednesday, October 4. but capable, under favourable conditions, of growing again,

Mr. PETER SQUIRE in the Chair. until by the perfect balance of the atomic attractions within they have ultimately arrived at maturity.

This, the first meeting of the season, was as usual devoted We have thus been led, step by step, to a distinction of to the distribution of the prizes gained by the pupils of a novel kind, that of finished and unfinished molecules ; or,

the Society during the past session. The Professors preto use the more frequently employed expression, that of sented their Reports, and the Chairman distributed the saturated and non-saturated compounds. I need not tell prizes with a few words of advice and encouragement to you that this distinction carries us to the threshold of a the receivers. The names of the prize-men are as under : new field of research, hitherto crossed only by a small

Chemistry and Pharmacy. band of fearless pioneers, who are encountering difficulties


Mr. A. R. Hall on all sides. Admitting, as we are compelled to do, the

Certificate of Merit

F. Oldfield existence of what we have called unfinished molecules,

F. C. Clayton sve inquire under what special conditions, at what special

Botany and Materia Medica. stages the growth of a molecule may be arrested. How

Mr. F. Oldfeld

Medal is it that as yet the marsh-gas molecule is known only in

G. W. Self (equal) the finished state, CH4, that none of the fragmentary

Certificate of Merit

F. C. Clayton marsh-gases, CH3, CH,, and CH, which might exist, have

S. Applegate ever been obtained? Again, how is it that the molecule

H. W. Harris of hydride of ethyl exists, so to speak, finished and un

J. A. Thomas finished; and, lastly, that of the several fragmentary states

Practical Chemistry- Laboratory Class,

in which this molecule might be met with, two only

Medal .

Mr. A. Rose namely, the two states C,H, (olefiant gas), and cu,

Certificate of Merit

F. C. Clayton (acetylene)-have ever been observed ? We are thus

H. W. Harris brought face to face with some of the most deeply interest- Pereira Medal

A. Rose ing problems of chemical mechanics, in the solution of

Prizes for Herbaria. which the exertions of chemists are engaged at the present

Silver Medal

Mr. J. W. White moment. I must not, however, dwell upon the interest Honorary Certificate

Isaiah Tansley attached to this new line of inquiry, upon the numerous

Jacob Bell Scholarships. experiments which the idea of saturated and non-satu- There was no candidate this year for the Senior, so the rated compounds has already suggested, and on the influ- Council allotted two Junior Scholarships. These were ence it is likely to exercise on the direction of chemical gained by Mr. A. R. Hall and Mr. S. Applegate. investigation for some time to come.

Nor am I permitted to follow these speculations into another direction. I have to forego, more especially, the MANCHESTER LITERARY AND PHILOSOPHICAL pleasure of submitting to you some of the ingenious explanations which Professor Kekulé, to whom we are greatly

SOCIETY. indebted for the development of this branch of chemistry,

Ordinary Meeting, October 3, 1865. has advanced for the elucidation even of saturated com

EDWARD SCHUNCK, Ph.D., F.R.S., $c., Vice-President, in pounds of anomalous constitution. Tempting though the

the Chair, further elaboration of this subject may appear, it would A PAPER was read " On the Internal Heat of the Earth as lead me inevitably beyond the legitimate limits of a Friday a Source of Motive Power," by Mr. GEORGE GREAVES, evening lecture at the Royal Institution.

M.R.C.S. It has been very generally admitted that coal Indeed, my time, and I fear your patience, are exhausted, will not cease to be furnished because of the exhaustion and I must add but few concluding words. Your atten- T of the stores of the mineral now existing in the coal

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measures ; and further, that the obstacles to the continued perhaps, see a recommendation in what the author conworking of the mines will not be engineering difficulties. siders an objection. The increased depth from which the coal will have to be Cholera is still the subject of many communications. brought may add to the cost, but at that increased cost it In one of these M. R. De Wouves says that the premoniwill still be for a long time obtainable. The author con- tory diarrhæa should always be treated with a purgative sidered the real insurmountable obstacle to be the high to procure the expulsion of peccant matter in the intestemperature of the lower portions of the carboniferous tines. In another M. G. Grimand gives a succinct his strata. That temperature had been shown to be at a tory of the recent outbreak in Marseilles, which seems to depth of 4000 feet at least 120° Fahr., a degree of heat prove conclusively the fact of the importation of the disease in which human beings cannot exist for any length of time, from Alexandria. much less use any exertion. It had occurred to the author to inquire whether the very agency which will prevent the continued supply of fossil fuel might not be

NOTICES OF BOOKS. made the means of rendering that supply unnecessary whether, in short, the internal heat of the earth might Dublin International Exhibition of Arts and Manufactures : not to some extent be utilised. One or two modes of Reports of the Juries, and List of the Awards. Dublin : doing this had presented themselves to his mind. One of 1865. these might, he conceived, be the direct production of The reporter on Section II. is Mr. Tichborne, who kindly steam power by bringing a supply of water from the sur- furnished us with notes on this part of the Exhibition ; we face in contact with the heated strata by means of artesian have consequently but little to add now on the subject. borings or otherwise.

There are, however, some remarks by Dr. Maxwell Simpson, on the articles exhibited by Henner and Co., of St.

Gall, Switzerland, which some of our readers may thank ACADEMY OF SCIENCES.

us for extracting. The firm exhibited some chemical proOctober

ducts which are difficult to find in commerce. These were 9.

found to be what may be termed very fair commercial speM. DB CIZANCOURT presented a memoir “ On the Allotropic cimens ; and Dr. Simpson remarks that it offers great Conditions of Iron.The author, like Berzelius, recog- facilities for original research that such substances can be nises two allotropic states of this metal, and adopts the procured in small quantities and at reasonable prices. same names for them-ferrosum and ferricum. Ferrosum Amylene (C,H,0) was one of the substances examined. is the metal from ores containing protoxide ; ferricum is Almost the entire quantity taken distilled over between obtained from the anhydrous peroxide ores. The most 35° to 45° C. The distillate on being agitated with a characteristic form of ferrosum is the white crystalline solution of chloride of iodine, yielded chloro-iodide of cast iron (Spiegel Eisen), commonly obtained from the amylene (C,H,CII) a new body, an account of which has carbonate, and is best produced at a low temperature. not yet been published. The iodide of allyle (C3H,I) is This form of iron has a strong affinity for carbon. Chemi- also a good product, the greater part distilled over between cally it must be classed among the bodies which unite with 100° to 1066 C.; on being agitated with metallic mercury one atom of oxygen. Ferricum also combines with carbon it became a mass of yellow crystals, the mercuro-iodide of at high temperatures, but deposits it again on cooling. allyle [(CH3)Hg,I]. The butylic alcohol distilled over This form of iron gives the malleable metal, and also between 104 to 120° C., and treated with iodine and blistered iron. The author states that while ferrosum phosphorus, yielded iodide of butyle, the boiling-point of easily passes into ferricum, the inverse change cannot be which was about 121° C.” effected. Ferricum belongs to that class of bodies which In the Report on Section IV. we find an account of combine at least with three atoms of oxygen and often more, "wood-stuffs" for paper-making, prepared by Roether, of but always an uneven number of atoms. This memoir Cassel. The samples were made from four woods, the will have considerable interest for metallurgists, and we linden, aspen, pine, and Scotch fir. The best qualities of shall therefore give it at length.

these, it seems, can be sold for 138. and 168. the 110 lbs. M. Bultinck presented a note “On the Use of Magnesium “The samples of papers,” says the Report, “made from in Voltaic Piles in Place of Zinc," Our readers can mixtures of rags with different proportions of these stuffs' imagine the results. The author shows that a short chain of are excellent, and show a decided progress in wood paper twenty elements, each composed of thirty-five millimetres manufacture since 1862. Among them may be specially of thin silver and magnesium wires, wound about pieces of mentioned a good writing paper containing 45 per cent. of caoutchouc and properly connected, will produce all the Scotch fir stuff; an excellent lapping paper containing 65 effects, chemical, physical, and physiological, of a long per cent. ; and a coloured lapping tissue paper which is exPulvermacher's chain when simply moistened with pure ceedingly strong, containing 50 per cent. of wood-stuff." water.

These articles and the process by which the stuff is proM. Jennet presented a note “ On the Clarification of duced, deserve the notice of our manufacturers ; but no Pealy Waters by Alum.". Most of our readers will have account of the process is given in the Report. heard of a method of clarifying and rendering portable The Report on Section XXX., Photographs, furnishes certain muddy waters by stirring or shaking up with them us with a very good account of Mr. Swan's casket portraits, a very small quantity of finely powdered alum. Then, after an ingenious novelty which deserves notice :standing a few minutes, the suspended impurities deposit, “One of the most curious novelties in the photographic and the water becomes perfectly bright, and at the same exhibition is the production of what is called casket time extremely palatable. The explanation of this is as portraits,' specimens of which are contributed by Mr. follows :-In dissolving, the alum splits up into sulphate Swan, the inventor. For such a really ingenious, original, of potash and sulphate of alumina. The former remains and scientific contrivance, it seems that the author might in solution in the water ; the latter decomposes, and the have found a more appropriate name, designating more insoluble alumina unites with and carries down the sus properly the principles upon which it is based, and the pended organic impurities ; while the sulphuric acid acts manner of its construction. It is, in fact, neither more on the alkaline and earthy carbonates, forming sulphates not less than a real stereoscope, in a different form from and setting free carbonic acid. The biphosphate of alumina, that well-known instrument. although slower in its action, the author thinks would be “Without being conscious of it the observer has before a better clarifier if the carbonic acid set free did not dis- his eyes, as in the ordinary stereoscope, a picture com. solve some of the neutral phosphate. Some persons will, I posed of two different photographs super-posed, each one

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