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Home > Dictionary of Science Quotations > Scientist Names Index K > August Kekulé Quotes

Thumbnail of August Kekulé (source)
August Kekulé
(7 Sep 1829 - 13 Jul 1896)

German chemist who is traditionally attributed with devising the ring structure of carbon atoms in organic molecules. He also envisioned double or even triple bonds between carbon atoms in chains.

Science Quotes by August Kekulé (9 quotes)

Portrait of August Kekulé (1890), upper body facing forward, hand on pages of a book on table, seated behind table
August Kekulé at age 60
painted by Heinrich von Angeli (1890) (source)

Carbon is, as may easily be shown and as I shall explain in greater detail later, tetrabasic or tetratomic, that is 1 atom of carbon = C = 12 is equivalent to 4 At.H.
— August Kekulé
'On the so-called Copulated Compounds and the Theory of Polyatomic Radicals', Annalen (1857), 4, 133. Trans. in J. R. Partington, A History of Chemistry (1972), Vol. 4, 536.
Science quotes on:  |  Bond (26)  |  Carbon (49)  |  Compound (58)

During my stay in London I resided for a considerable time in Clapham Road in the neighbourhood of Clapham Common... One fine summer evening I was returning by the last bus 'outside' as usual, through the deserted streets of the city, which are at other times so full of life. I fell into a reverie (Träumerei), and 10, the atoms were gambolling before my eyes! Whenever, hitherto, these diminutive beings had appeared to me, they had always been in motion: but up to that time I had never been able to discern the nature of their motion. Now, however, I saw how, frequently, two smaller atoms united to form a pair: how the larger one embraced the two smaller ones: how still larger ones kept hold of three or even four of the smaller: whilst the whole kept whirling in a giddy dance. I saw how the larger ones formed a chain, dragging the smaller ones after them but only at the ends of the chain. I saw what our past master, Kopp, my highly honoured teacher and friend has depicted with such charm in his Molekular-Welt: but I saw it long before him. The cry of the conductor 'Clapham Road', awakened me from my dreaming: but I spent part of the night in putting on paper at least sketches of these dream forms. This was the origin of the 'Structural Theory'.
— August Kekulé
Kekule at Benzolfest in Berichte (1890), 23, 1302.
Science quotes on:  |  Chain (50)  |  Compound (58)  |  Hermann Franz Moritz Kopp (2)  |  Structure (225)  |  Theory (696)

I was sitting writing at my textbook but the work did not progress; my thoughts were elsewhere. I turned my chair to the fire and dozed. Again the atoms were gambolling before my eyes. This time the smaller groups kept modestly in the background. My mental eye, rendered more acute by the repeated visions of the kind, could now distinguish larger structures of manifold confirmation: long rows, sometimes more closely fitted together all twining and twisting in snake like motion. But look! What was that? One of the snakes had seized hold of its own tail, and the form whirled mockingly before my eyes. As if by a flash of lightning I awoke; and this time also I spent the rest of the night in working out the rest of the hypothesis. Let us learn to dream, gentlemen, then perhaps we shall find the truth... But let us beware of publishing our dreams till they have been tested by waking understanding.
— August Kekulé
Kekule at Benzolfest in Berichte (1890), 23, 1302.
Science quotes on:  |  Aromatic (2)  |  Carbon (49)  |  Dream (167)  |  Molecule (133)  |  Ring (16)  |  Snake (16)  |  Structure (225)  |  Truth (928)  |  Understanding (325)  |  Verification (27)

If we wish to give an account of the atomic constitution of the aromatic compounds, we are bound to explain the following facts:
1) All aromatic compounds, even the most simple, are relatively richer in carbon than the corresponding compounds in the class of fatty bodies.
2) Among the aromatic compounds, as well as among the fatty bodies, a large number of homologous substances exist.
3) The most simple aromatic compounds contain at least six atoms of carbon.
4) All the derivatives of aromatic substances exhibit a certain family likeness; they all belong to the group of 'Aromatic compounds'. In cases where more vigorous reactions take place, a portion of the carbon is often eliminated, but the chief product contains at least six atoms of carbon These facts justify the supposition that all aromatic compounds contain a common group, or, we may say, a common nucleus consisting of six atoms of carbon. Within this nucleus a more intimate combination of the carbon atoms takes place; they are more compactly placed together, and this is the cause of the aromatic bodies being relatively rich in carbon. Other carbon atoms can be joined to this nucleus in the same way, and according to the same law, as in the case of the group of fatty bodies, and in this way the existence of homologous compounds is explained.
— August Kekulé
Bulletin de la Societé Chimique de France (1865), 1, 98. Trans. W. H. Brock.
Science quotes on:  |  Aromatic (2)  |  Carbon (49)  |  Homologous (3)

Originally a pupil of Liebig, I became a pupil of Dumas, Gerhardt and Williamson: I no longer belonged to any school.
— August Kekulé
J. R. Partington, A History of Chemistry (1970), Vol. 4, 533.
Science quotes on:  |  Jean-Baptiste-André Dumas (9)  |  Charles Gerhardt (3)  |  Justus von Liebig (38)  |  Pupil (36)  |  School (119)  |  Student (203)  |  Alexander William Williamson (2)

The question whether atoms exist or not... belongs rather to metaphysics. In chemistry we have only to decide whether the assumption of atoms is an hypothesis adapted to the explanation of chemical phenomena... whether a further development of the atomic hypothesis promises to advance our knowledge of the mechanism of chemical phenomena... I rather expect that we shall some day find, for what we now call atoms, a mathematico-mechanical explanation, which will render an account of atomic weight, of atomicity, and of numerous other properties of the so-called atoms.
— August Kekulé
Laboratory (1867), 1, 303.
Science quotes on:  |  Atom (280)  |  Atomic Weight (6)  |  Hypothesis (252)  |  Knowledge (1306)  |  Mechanism (52)  |  Property (126)  |  Question (404)  |  Reaction (62)

The separate atoms of a molecule are not connected all with all, or all with one, but, on the contrary, each one is connected only with one or with a few neighbouring atoms, just as in a chain link is connected with link.
— August Kekulé
'The Scientific Aims and Achievements of Chemistry', Nature (1878), 18, 212.
Science quotes on:  |  Atom (280)  |  Bond (26)  |  Chain (50)  |  Molecule (133)

We define organic chemistry as the chemistry of carbon compounds.
— August Kekulé
Lehrbuch der Organischen Chemie (1861), Vol. 1, 11. Trans. W. H. Brock.
Science quotes on:  |  Carbon (49)  |  Compound (58)  |  Nomenclature (138)  |  Organic Chemistry (33)

When the simplest compounds of this element are considered (marsh gas, chloride of carbon, chloroform, carbonic acid, phosgene, sulphide of carbon, hydrocyanic acid, etc.) it is seen that the quantity of carbon which chemists have recognised as the smallest possible, that is, as an atom, always unites with 4 atoms of a monatomic or with two atoms of a diatomic element; that in general, the sum of the chemical units of the elements united with one atom of carbon is 4. This leads us to the view that carbon is tetratomic or tetrabasic. In the cases of substances which contain several atoms of carbon, it must be assumed that at least some of the atoms are in some way held in the compound by the affinity of carbon, and that the carbon atoms attach themselves to one another, whereby a part of the affinity of the one is naturally engaged with an equal part of the affinity of the other. The simplest and therefore the most probable case of such an association of carbon atoms is that in which one affinity unit of one is bound by one of the other. Of the 2 x 4 affinity units of the two carbon atoms, two are used up in holding the atoms together, and six remain over, which can be bound by atom)' of other elements.
— August Kekulé
'Ueber die Konstitution und die Metamorphosen der chemischen Verbindungen', Annalen (1858) 5, 106. Trans. in J. R. Partington, A History of Chemistry (1972), Vol. 4, 536.
Science quotes on:  |  Affinity (14)  |  Bond (26)  |  Carbon (49)  |  Carbonic Acid (4)  |  Chloroform (2)  |  Compound (58)  |  Methane (7)

Quotes by others about August Kekulé (4)

People have wracked their brains for an explanation of benzene and how the celebrated man [Kekulé] managed to come up with the concept of the benzene theory. With regard to the last point especially, a friend of mine who is a farmer and has a lively interest in chemistry has asked me a question which I would like to share with you. My “agricultural friend” apparently believes he has traced the origins of the benzene theory. “Has Kekulé,” so ran the question, “once been a bee-keeper? You certainly know that bees too build hexagons; they know well that they can store the greatest amount of honey that way with the least amount of wax. I always liked it,” my agricultural friend went on, “When I received a new issue of the Berichte; admittedly, I don't read the articles, but I like the pictures very much. The patterns of benzene, naphthalene and especially anthracene are indeed wonderful. When I look at the pictures I always have to think of the honeycombs of my bee hives.”
A. W. Hofmann, after-dinner speech at Kekulé Benzolfest (Mar 1890). Trans. in W. H. Brock, O. Theodor Benfrey and Susanne Stark, 'Hofmann's Benzene Tree at the Kekulé Festivities', Journal of Chemical Education (1991), 68, 888.
Science quotes on:  |  Bee (27)  |  Benzene (4)  |  Hexagon (4)

To Avogadro and Cannizzaro, as to Couper and Kekulé, the molecules and atoms considered in this great theory were real objects: they were thought of the same way as one thinks of tables and chairs.
On the Operational Interpretation of Classical Chemistry', British Journal for the Philosophy of Science (1955), 6, 32. In Mary Jo Nye, From Chemical Philosophy to Theoretical Chemistry (1993), 58
Science quotes on:  |  Atom (280)  |  Count of Quaregna Amedeo Avogadro (3)  |  Stanislao Cannizzaro (2)  |  Chair (11)  |  Molecule (133)  |  Table (36)  |  Theory (696)

I have no patience with attempts to identify science with measurement, which is but one of its tools, or with any definition of the scientist which would exclude a Darwin, a Pasteur or a Kekulé. The scientist is a practical man and his are practical aims. He does not seek the ultimate but the proximate. He does not speak of the last analysis but rather of the next approximation. His are not those beautiful structures so delicately designed that a single flaw may cause the collapse of the whole. The scientist builds slowly and with a gross but solid kind of masonry. If dissatisfied with any of his work, even if it be near the very foundations, he can replace that part without damage to the remainder. On the whole, he is satisfied with his work, for while science may never be wholly right it certainly is never wholly wrong; and it seems to be improving from decade to decade.
The Anatomy of Science (1926), 6-7.
Science quotes on:  |  Analysis (166)  |  Approximation (22)  |  Collapse (17)  |  Damage (28)  |  Definition (192)  |  Dissatisfaction (6)  |  Flaw (10)  |  Foundation (108)  |  Improvement (74)  |  Masonry (3)  |  Measurement (161)  |  Sir Isaac Newton (333)  |  Louis Pasteur (81)  |  Practical (133)  |  Progress (368)  |  Right (197)  |  Satisfaction (56)  |  Structure (225)  |  Ultimate (84)  |  Wrong (139)

If you want to become a chemist, you will have to ruin your health. If you don't ruin your health studying, you won't accomplish anything these days in chemistry.
Liebig's advice to Kekulé.
Quoted in Berichle der Deutschen Chemishen Gesellschaft, 23, 1890. Trans. W. H. Brock.
Science quotes on:  |  Accomplishment (80)  |  Chemist (89)  |  Health (156)  |  Study (476)

See also:
  • 7 Sep - short biography, births, deaths and events on date of Kekulé's birth.

Carl Sagan Thumbnail In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. (1987) -- Carl Sagan
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