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Council, which, I doubt not, would take them into careful | shall offer a few remarks, is a clause relating to "
Laboratory, Westminster Hospital,
now employed as chemists." I would urge every chemist to read this carefully, and then ask himself whether he be eligible for the membership of the proposed Institute. Many of my friends, veterans of upwards of ten years, would certainly be excluded, and I doubt whether it would be possible for the gentlemen who sat on either side of Prof. Abel at the organisation meeting at Burlington House to squeeze in except by a side door, which, to say the least, renders the thing ridiculous.
In a former communication I pointed out what I considered to be the great desideratum, namely, unity amongst chemists, which I thought might be effected by the timehonoured Chemical Society. Dr. Wright's elaborate summing up has so far discountenanced this idea that I think the time has come for chemists most sincerely to consider the advisability of bringing this about by independent action. The success of any movement to found depend upon its receiving the support of the present genea representative chemical corporation must ultimately ration of chemists. To do this effectively all chemists, It is premature to lay down any unauthorised restrictions scientific or technical, must be invited to join and assist. as to age or other qualifications, and it would be invidious thenay, impertinent for Chemist A to sit in judgment on the qualifications of his brother B.
To the Editor of the Chemical News. SIR,-You have very justly reminded your readers that systematic blackballing is not a new thing in the Chemical Society, and that in 1867 there was an outbreak of blackballing which compelled the Council of the Society to take action. In point of fact systematic blackballing is the form in which the dissatisfaction which generally prevails in the Chemical Society makes itself manifest The structure of the Chemical Society, like that of other so-called learned societies, is very peculiar. Nominally the Chemical Society is a republic of the most democratic character, inasmuch as the Council and officers hold office solely by virtue of a majority of votes given by Fellows, and each Fellow has only one vote.
from time to time.
Really and in practice, however, the elective power of the Society remains permanently in abeyance; and the Council of one year re-elects itself and its nominees to form the Council of the next year. It is notorious how thinly the anniversary meetings are attended, and that not one-tenth (and probably not one-twentieth) of the 600 or 700 Eellows of the Society take any part in the election of the Council of the Society. Inevitably this state of things develops "officialism," and leads to all those evils the existence of which is announced by the systematic blackballing which is so prevalent in the Chemical Society.
The best remedy would be to induce the Society as a whole to vote for its Council. Failing that, it would be wise to draw lots for the Council, which might afterwards choose the President and officers. It does seem to me that a sham annual election must be a source of danger to any Society. I am, &c.,
J. ALFRED WANKLYN.
To the Editor of the Chemical News. SIR,-"History is said to repeat itself." Of all our oftrepeated phrases this one is perhaps the most illusory. With equal truth the same might be said of waves volcanic outbursts. But just as the ripple may be the precursor of the tempest, the underground rumbling may betoken a violent eruption.
In the Chemical Society in 1867 signs of dissatisfaction were manifest; we are told that a "somewhat widespread dissatisfaction" now exists, and relating too to the same cause—that is, to the election of Fellows. The '67 agitation was productive of only a small amount of good, but it by no means follows that the '76 or '77 movement will be of so little import to the chemist. Change of time has brought change of aspirations. Intestine wars among the Fellows are a natural consequence of their heterogeneous character. The idle never yet agreed well with the industrious. The chemist and non-chemist cannot be expected to blend and harmonise one with the other. This is well illustrated by the so-called "organisation" movement, one of the objects of which is to sift these incompatible elements.
The only scheme before us relating to the subject is the one published in the CHEMICAL NEWS (vol. xxxiii., page 240) by the "clients" of Mr. Pettengill, which I believe to be the most suicidal and impracticable possible to have been devised.
The only part of the scheme which immediately concerns the present generation of chemists, and on which I
Again, any scheme, to be successful, must be comprehensive, and sufficient to attract all men now engaged as chemists, or it will most assuredly be annihilated by the successful opposition of those whom it would vilify, ostracise, and threaten with ruin.-I am, &c., Dulwich College, July 4, 1876.
To the Editor of the Chemical News. SIR,-Now that the subject of organisation amongst chemists is being so largely discussed in the columns of the CHEMICAL NEWS, I will beg permission to make known to your readers some of the details of a case in which the initials F.C.S. appear in an advertising pamphlet in a manner which cannot but be considered as most derogatory to the science.
The particular case to which I am about to direct atten-
ther comment upon these extracts would be unnecessary.
Belle Vue House, Twickenham, July 3, 1876.
[The discussion on "The Chemical Society" and the Organisation" movement, having occupied a great deal of our space during the last few weeks to the exclusion of
Chemical Notices from Foreign Sources.
other important matter, we are compelled to decline to insert any more letters on the subject for the present, unless, indeed, our correspondents have any new information to give, and then it will be necessary for the letters to bear the writers' names.-Ed. C. N.].
ANALYSIS OF PEROXIDE OF MANGANESE.
To the Editor of the Chemical News. SIR,-The analysis of a sample of peroxide of manganese, given by Dr. Phipson in the CHEMICAL NEWS (vol. xxxiii., p. 243) is of interest from the large number of elements found. There is one point on which I (and possibly other of your readers) should like further information. author writes:-"The quantity of MnO2 being calculated in the usual manner, the rest of the manganese was considered as Mn2O3, though there are doubtless small quantities as MnO." As I frequently require to make complete analyses of manganese ores, I am curious to know how Dr. Phipson distinguished the MnO2 from the Mn2O3. Both these oxides exercise an oxidising action, though of course the available oxygen of the latter is only half that of the former. As all the methods of determining MnO2 (as distinguished from MnO) with which I am acquainted are based, directly or indirectly, on its oxidising power, how did Dr. Phipson distinguish it from the remaining oxide of manganese if the latter was Mn2O3? Is it not evident that the oxide which was not recognised by any
process of " chlorimetry must have been MnO? Is it not impossible to distinguish analytically between Mn203 and MnO+MnO2? If so, Dr. Phipson has counted his oxygen twice over.-I am, &c.,
Sheffield, July 3, 1876.
ALFRED H. ALLEN.
Radiometer of Mr. Crookes.-M. W. de Fonvielle.The experiments executed by M. Darlu de Roissy and myself in the photometric laboratory of the gas works at Vilette appear to us to confirm the opinions put forward by Mr. Crookes. The procedure which enabled us to change at will the direct movement to the right into an inverse movement to the left seems to agree with the arguments of this eminent chemist before the Royal Society of London. We obtained the normal rotation under the action of radiant heat, but after having left the radiometer exposed for five minutes to a temperature of 45° C. we plunged it rapidly into a bath of cold water at 15° C. The rotation to the right ceased, the instrument stopped for a moment, and then began to revolve to the left with a rapidly increasing speed, which reached a revolution and a half per second. This inverse movement ceased almost as quickly as it had begun. At the end of half a minute the movement to the right re-commenced under the action of the solar rays which fell upon the absorbent surfaces of the radiometer in the midst of the liquid mass, and withou the possibility of heating by conduction. M. Fizeau, with reference to this communication, remarked that the conclusions of the author in favour of the existence of an impulsive force in the rays of light, seemed to him to require the most formal reservations. The ingenious instrument of Mr. Crookes seemed to be in reality a thermic apparatus, in which the rotation, with all its circumstances, may be simply ascribed :-(1) To a slight with the ambient medium under the influence of light. excess of temperature acquired by the discs as compared (2) To the inequality of the emissive and absorbent powers of the two opposite surfaces of each disc, the one blackened and the other polished. (3) To the inevitable presence in the apparatus of a small quantity of elastic fluid (gas or watery vapour), the layers of which close to the blackened surface may acquire a slight excess of elastic force sufficient to propel the discs whose mobility is extreme. Certain inverse movements temporarily produced by cold
CHEMICAL NOTICES FROM FOREIGN will be the analogous results of the same causes.
NOTE. All degrees of temperature are Centigrade, unless otherwise expressed.
Comptes Rendus Hebdomadaires des Seances, de l'Acadenie des Sciences. No. 22, May 29, 1876.
over, M. Fizeau, at the request of several members of the Academy, made in their presence, at the end of the sitting, certain experiments with the instrument. He showed that if a stream of solar rays, limited by a screen, were thrown upon the disc so as to strike merely the polished surfaces of the discs the rotatory movement was still produced, but in such a direction that each disc moved to meet the solar rays instead of retiring from them, as ought to take place if the motion were the result of an impulsive power of light. Previous experiments have shown, further, that this result does not depend on accidental reflections in the interior of the apparatus.
Atomic Constitution of Bodies.-M. de St.-Venant. -The author concludes that we cannot, without placing ourselves in contradiction with the totality of celestial and terrestrial phenomena regard atoms as corpuscles formed of hard and continuous matter, but that there is Charge assumed by the Disc of the Electrophorus. nothing contradictory in considering them as material-M. E. Douliot.-The charge received by the disc, and points endowed with all the properties, save extension, which it carries away when raised by its isolating handle, which we observe in visible and tangible bodies. is proportional to its radius.
New Remarks on the Real Existence of a Matter formed of Isolated Atoms comparable to Materials Points.-M. Berthelot.-The conception of a single and fundamental kind of matter, of which the multiple states of aggregation constitute the elementary bodies that we know, with their specific properties-a conception to which eminent minds give their adhesion-seems to imply that the atomic masses of our elements are far removed from the condition of true atoms.
Salts Formed by the Peroxide of Manganese.-M. E. Fremy. The author shows that the peroxide of manganese under different circumstances may behave either as indifferent, acid or basic, and forms salts in which he considers that it plays the part of a base.
Examination of the Possible Mechanical Action of Light Study of the Radioscope of Mr. Crookes.M. A. Ledieu. The fact that the luminous rays produce generally little heat would show precisely that the vis viva which the luminiferous vibrations of the ether give off must tend to convert itself almost entirely into motion.
Theory of Spectra; Observations on the Last Communication of Mr. Lockyer.-M. Lecoq de Boisbaudran.-Reserved for insertion in full.
Constitution of Propylenic Monochlorhydrins, and on the Law of Addition of Hypochlorous Acid.-M. L. Henry.-Not suitable for abstraction.
Quino-acetate of Calcium.-M. E. Gundelach.-The author examining a commercial quinate of calcium found that it was a double salt, formed of equal molecules of quinate and acetate of lime.
No. 23, June 5, 1876.
Thermic Formation of Ozone.-Ozone is a body formed with absorption of heat, which it evolves in its oxidising actions-a fact which explains the superiority of its energy to that of ordinary oxygen. This excess of heat or of energy has been stored up under the influence of electricity, an excess remarkable because we have here the formation of a body more condensed than that from
July 7, 1876.
Chemical Notices from Foreign Sources.
movements of the earth, as a whole, can be effected by the solar radiations. He considers, however, that we have here a very natural explanation of the form of the tails of
which it is produced, although condensation, in general, | the luminous rays. M. Ledieu does not hold that the causes the liberation and not the absorption of heat, as takes place here. This is probably the only instance of a gas supposed to be simple and yet capable of presenting two distinct isomeric modifications in the gaseous state. Absorption of Free Nitrogen by Organic Matters at Ordinary Temperatures.-M. Berthelot.-The author finds that free nitrogen is absorbed at ordinary temperatures by organic compounds under the influence of the electric effluve (silent discharge). He insists on this new cause of the fixation of atmospheric nitrogen in nature. It produces condensed nitrogenous compounds belonging to the class of the humic principles. However limited may be the effects at each moment, and on each particular spot of the earth's surface, they may nevertheless become considerable, in virtue of the extent and continuity of a reaction universal and never ceasing.
Report on several Memoirs by M. Allard relating to the Transparence of Flames and of the Atmosphere, and to the Visibility of Lighthouses with Flashing Lights.-MM. Jamin, Puiseux, and E. Becquerel. M. Allard finds that the luminous intensity of the flames of lamps with concentric wicks increases more rapidly than the consumption of oil, and equally with the visible surface. The mean value of the coefficient of the transparency of flame, for a thickness of 1 centimetre, is expressed by the number o'80.
Law of Dulong and Petit.-M. A. Terreil.-M. Terreil holds that there are only two phases when bodies possess their true absolute specific heat. The first of these is the moment when the body is in the gaseous state, and the other that when it has lost this state, no matter whether it has become liquid or solid. He admits, besides, that at the moment of these two phases the forces which modify the absolute specific heats have not yet come into action. In order to distinguish the specific heats, as he understands them, from the admitted specific heats, he gives them the name of chemical specific heats. He finds that the specific heat of bodies doubles when they cease to be gaseous.
Perturbing Influence of Neighbouring Masses on the Form and the Disposition of Crystals.-M. Ch. Brame.—Not adapted for abstraction.
Inconvenience of Ropes of Copper Wire as Lightning Conductors.-M. R. Francisque-Michel.The author holds that a lightning-conductor should have at least a section of 350 to 400 square millimetres.
Influence of Certain Salts of Lime on Saccharimetry.-M. A. Müntz.-The author concludes that the rotatory power of cane-sugar in presence of a given salt is sensibly constant for one and the same quantity of salt dissolved in one and the same volume of liquid, whatever The decrease may be the ratio of the salt to the sugar. of rotatory power is, up to a certain point, proportional to the quantity of salt dissolved.
Derivative of Acetyl-acetic Ether: Oxy-pyrotartaric Acid.-M. E. Demarçay.-Not suited for abstraction.
Origin of Organic Ferments.-M. L. Pasteur.-This paper is an extract from a work about to appear under the title "Etudes sur la Bière." The author combats M. Fremy's hypothesis of "hemiorganism," and quotes Dr. Tyndall's remarks on the writings of Dr. Bastian. Examination of the Possible Mechanical Action of Light Study of the Radiometer of Mr. Crookes.M. A. Ledieu (continuation).-The author having explained his theory to M. Fizeau, this eminent academician proposed an experiment by polarising a pencil of rays. In this manner, in fact, in accordance with his theory, we ought to obtain a minimum impulsion, or none at all when the plane of polarisation is made to pass along the axis of the radiometer. On the contrary, the maximum impulsion should be obtained at 90° from the first position. This experiment was made with an excellent instrument by M. Alvergniat, but it gave no conclusive result. M. Fizeau then caused an ordinary pencil of rays to fall exclusively upon the blackened discs, and thus obtained a movement more accelerated than when the pencil fell at once upon both kinds of surfaces. He then operated in an analogous manner upon the bright surfaces, taking care to incline the pencil of rays so that no reflection might be thrown from the polished surfaces upon the black ones. strument continued to revolve, but with a reduced speed. This latter experiment would lead us to condemn all radiant influence, since this would attract in one case and repel in the other. The author's theory would therefore seem confounded by such a result, as well as every other explanation based upon the doctrine of emission. But on examining more closely, we are led to remark that in all the experiments related there is reflection of light upon the glass of the globe, and that, besides, when these rays are polarised, the plane of polarisation, after reflection, is no longer presented in the same direction as regards the faces of the discs. We must then conclude that further experiMetallisation of Organic Bodies to render them fit ments are absolutely required to elucidate the question. to receive Galvanic Deposits.-M. P. Cazeneuve. The The author, then, quoting the opinion of M. Fizeau, given author saturates the bodies in question with alcoholic in the present number of the CHEMICAL NEWS, continues-nitrate of silver, which is then reduced by the solar light, "This opinion, emanating from so distinguished a savant, must assuredly be taken into high consideration. Nevertheless, considering the regularity, the definite character, and the certainty of the revolution of the instrument, always in one and the same direction, the explanation of M. Fizeau does not satisfy us entirely, and the debate does not seemed to be closed. He then suggests the following experiments:-Illuminate an ordinary radiometer, i.e., with discs alternately polished and blackened in the direction of its axis. The instrument ought to revolve in the same direction as when the pencil of rays illuminates the axis vertically, and the rotation even ought to be accelerated. Second. Construct an apparatus all the discs of which shall be left bright so as to reduce to a minimum the influence of the reflections upon the glass; then to throw a pencil of rays upon the disc situate on one and the same side as relates to the axis of the instrument. If the rotation is really due to the mechanical action of light the instrument will turn as if the discs were repelled by
Combustion of Organic Matters under the Double Influence of Heat and Oxygen.-M. D. Loiseau.-For the complete combustion of volatile products it is necessary to operate in tubes whose interior diameter is so much the greater as the current of oxygen is more feeble.
or preferably by means of mercurial vapours.
Determination of Sulphuric Acid and Soluble Sulphates by means of Standard Solutions.-M. H. Pellet.-The author first precipitates the sulphuric acid by chloride of barium in excess, precipitates the excess of chloride of barium with yellow chromate of potash, and finally determines the chromate with standard solutions of protochloride of iron and permanganate of potash.
Les Mondes, Revue Hebdomadaire des Sciences,
The Radiometer of Mr. Crookes.-M. Trouve.-I am desirous of knowing if Mr. Crookes has given a theory, or rather a logical definition, of the movement of his instrument in presence of light. On my part, I find no satisfactory explanation of this phenomenon save in a comparison with the theory of the electric mill. I ascribe, therefore, the movement to the diffusion of the fluid, and
not to a direct action exerted by light. What confirms | College. Branch XVI. (Logic and Moral Philosophy.)—
Reimann's Farber Zeitung,
Mineralogical Society of Great Britain and Ireland.-A local meeting of the Cornish members was held at the Public Rooms, Redruth, on Saturday, July 1, when the following papers were read, the chair being taken by Dr. C. Le Neve Foster, Her Majesty's Inspector of Mines for the district :-" On a New Mineral from West Phoenix Mine," by J. H. Collins, F.G.S., with remarks by Dr. C. Le Neve Foster, B.A., &c. This is a hydrous phosphate of alumina and copper, resembling turquoise, but containing much more phosphoric acid and water and less alumina. Mr. Collins has called it Henwoodite, after M. Prinvault has communicated to the Industrial the late W. Jory Henwood, F.R.S. "On the Occurrence Society of Rouen a process for obtaining a scarlet, the of Pyrophillite at Brookwood, and on New Mineral shade known as Persian red, from the chromate of lead. Localities in Devon and Cornwall," by Dr. C. Le Neve If carbonate of lead is digested with a cold solution of I Foster, B.A., &c. "On the Oxide of Iron enclosed in part of the neutral chromate of lead in 50 of water, so that two equivalents of the former may react with one of Calcite and Quartz, at the Mwyndy Mines, Glamorganthe latter compound, there is obtained in two days a crys-cosiderite Scorodite and Olivenite in Greenstone, at Terras "On the Occurrence of Pharmashire," by Wm. Vivian. talline precipitate of basic chromate of lead. If the supernatant liquid is boiled, it evolves carbonic acid, since Mine, St. Stephens," by J. H. Collins, F.G.S. Mr. B. Kitto, F.G.S., was elected Local Secretary for Cornwall, bicarbonate of potassa is present, and is converted into a solution of potash, which decomposes a part of the red subject to the approval of the Council. precipitate, so that it takes a violet-red colour, whilst the liquid turns yellow. The precipitate is too dull to be of any value. If it is washed with water, and treated with 4 per cent of its weight of dilute sulphuric acid (1 in 100), adding the acid slowly and stirring, and then neutralising with a dilute solution of soda, there is formed a mixture of sulphate and of basic chromate of lead, the colour passing into a fiery vermillion. The quantity obtained is about equal to the carbonate of lead employed. According to M. Prinvault, nitric or acetic acid may be used instead of sulphuric, but not hydrochloric. The proportions he employs are 25 grms. neutral carbonate of lead, with 10 grms. neutral chromate of potassa. He digests two days in the cold, boils for half an hour, filters, washes the precipitate, and treats it with 1 grm. of sulphuric acid diluted with 100 grins. of water. The new red cannot be fixed with albumen on account of its crystalline texture. It may, however, be possible to convert chrome orange into Persian red upon the fibre.
The Berlin daily papers are very busy with another supposed case of poisoning from the lining of a hat. A Government official, shortly after buying a new hat, was troubled with a very disagreeable eruption on his forehead. The affair is in the hands of the authorities.
Purpurin.-According to F. de Lalande's French patent purpurin may be obtained as follows:-100 parts alizarin and 100 of dry arsenic acid are heated with 1000 parts of sulphuric acid to 150°, until a sample taken out gives a deep red colour with soda. He then dilutes with 30 volumes of water, heats, and filters. The residue is used for dyeing. Instead of arsenic acid may be used antimonic acid, peroxide of manganese, or stannic acid.
Rosenstiehl has obtained a colouring matter in yellow metallic lamellæ by acting upon dry artificial alizarin with nitrous acid. With alumina it dyes yellow, and with iron mordants a red-violet, both which colours can be brightened with boiling soap lyes. It dyes best in distilled water or with addition of acetate of lime. stiehl considers it as nitro-alizarin.
University of London.-The following is the list of the candidates who have passed the recent D.Sc. Examination:-Branch IV. (Inorganic Chemistry.)-T. Carnelley, Owens College; F. Clowes, Royal College of Chemistry and private study. Branch VI. (Electricity, treated Experimentally.)-J. G. MacGregor, private study. Branch XII. (Vegetable Physiology.)-E. B. Aveling, University
ABRIDGMENTS OF PROVISIONAL AND COMPLete
An improved continuous horizontal apparatus for washing or
liquid passes from the feed-tank into the apparatus, and consecutively
through each of the compartments, by passing into each of the liquid
Improvements in furnaces for metallurgical operations, which im-
generator and hot-air bridge may be applied to steam boiler and other
Improvements in the manufacture of "consolidated coal." F. C.
NOTES AND QUERIES.
Our Notes and Queries column was opened for the purpose of giving and obtaining information likely to be of use to our readers generally. We cannot undertake to let this column be the means of transmitting merely private information, or such trade notices as should legitimately come in the advertising columns. Absorbing Power of Charcoal.-Can one of your readers oblige me with a simple method for ascertaining the absorbing power of charcoal samples?-DISINFECTOR,
HEMICAL NEWS Action of Certain Kinds of Filters on Organic Substances.
July 14, 1876.
A SOLUTION of hydrochlorate of morphia in common
As a further corroboration, advantage was taken of the reducing properties possessed by morphia, which decolourised standard solution of permanganate, and which may be titrated with such a solution.
Before submitting it to filtration 100 cubic centimetres of the solution of morphia reduced 8.5 c.c. of decinormal* permanganate solution.
After filtration 100 c.c. of the liquid did not reduce any appreciable quantity of the permanganate. Thus it has been proved that one single filtration through a thickness of 6 inches of "silicated carbon" is sufficient to remove morphia from a solution containing 132 m.grms. of the hydrochlorate of morphia in one litre of water (or 9'24 grains per gallon.)
Having arrived at this result, I next endeavoured to reach the limit of strength capable of being dealt with by these filters. I dissolved 2.739 grms. of hydrochlorate of morphia in 3 litres of distilled water, thereby getting a solution containing 913 m.grms. of that salt per litre of water (or 63.91 grs. per gallon).
This solution, as will be seen, is capable of decolourising decinormal permanganate solution at the rate of 59 c.c. of permanganate per 100 c.c. of the morphia solution.
It was poured on a very small silicated carbon filter; the first half of the filtrate was rejected and the second half examined. The filtrate was at first found to contain much morphia, but after making it pass and re-pass through the filter the morphia was so far reduced in quantity that 100 c.c. of the filtrate decolourised only 2 c.c. of decinormal permanganate, showing that about ths of the morphia had been absorbed by the filter. To attain this result, five or six passages through the filter were required.
Until I break up the filter and weigh the fragments of the cake, I cannot say with accuracy how much silicated carbon has been required to absorb the morphia. Roughly, however, the weight of the cake may be set down as 1000 grms, and, at that rate, 1000 grms. of silicated carbon is capable of absorbing at least 2 grms. of hydro
*This solution contained 0'4 milligramme of active oxygen per cubic centimetre.
chlorate of morphia. I propose, however, to make accurate
determinations of the extent to which "silicated carbon" may be loaded with morphia.
I am continuing the experiments, and, in the meantime, I cannot help pointing out how completely my experi ments have discredited the dictum that filtration through thick filters can only remove suspended matter.
A STUDY OF CHLORINE SUBSTITUTION.
IF modern chemistry gained a signal triumph over the
Abandoning the untenable ground then taken, it would now appear that hydrocarbons, and their oxy- or other derivatives, subjected to the action of chlorine, evince, among other multiple or additive results, at least two isomeric substitutional changes-one by which the hydride becomes a chloride, leaving the radical untouched; the other by which one H of the radical is replaced by one of Cl.
in the other, chloracetic hydride-
(C4H3O2)H. (C4H3O2)Cl. (C4H2ClO2)H.
Prof. Odling has treated this subject, but not with his accustomed felicity and clear_penetration (see Phil. Magazine, March, 1876," On the Formulation of the Paraffins and their Derivatives"):-"By the replacement of one CI for one H a great variety of paraffins are attainable, as C3H7C1, C4H,CI, &c., the residues constituting the paraffin or alcohol monad radicals, propyl, butyl, amyl, &c.
"But this action gives rise to at least two distinct isomers, and a study of their formative and transformative reactions leads to the conclusion that the difference be tween them depends upon whether they result from a substitution of the introduced radical for the H of a methyl, or of a methylen residue; the paraffin radicals resulting in this way from the introduction of a foreign radical in the place of H, &c., affording the means for their classifi cation. Thus ::