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and liquids cannot be cut。 Some things can be both split and cut； like
wood； though generally it is lengthwise that a thing can be split
and crosswise that it can be cut。 For； a body being divided into
many parts fin so far as its unity is made up of many lengths it is
apt to be split； in so far as it is made up of many breadths it is apt
to be cut。
A thing is viscous when； being moist or soft； it is tractile。 Bodies
owe this property to the interlocking of their parts when they are
composed like chains； for then they can be drawn out to a great length
and contracted again。 Bodies that are not like this are friable。
Bodies are compressible when they are squeezable and retain the
shape they have been squeezed into； incompressible when they are
either inapt to be squeezed at all or do not retain the shape they
have been squeezed into。
Some bodies are combustible and some are not。 Wood； wool； bone are
combustible； stone； ice are not。 Bodies are combustible when their
pores are such as to admit fire and their longitudinal pores contain
moisture weaker than fire。 If they have no moisture； or if； as in
ice or very green wood； the moisture is stronger than fire； they are
not combustible。
Those bodies give off fumes which contain moisture； but in such a
form that it does not go off separately in vapour when they are
exposed to fire。 For vapour is a moist secretion tending to the nature
of air produced from a liquid by the agency of burning heat。 Bodies
that give off fumes give off secretions of the nature of air by the
lapse of time： as they perish away they dry up or become earth。 But
the kind of secretion we are concerned with now differs from others in
that it is not moist nor does it become wind （which is a continuous
flow of air in a given direction）。 Fumes are common secretion of dry
and moist together caused by the agency of burning heat。 Hence they do
not moisten things but rather colour them。
The fumes of a woody body are called smoke。 （I mean to include bones
and hair and everything of this kind in the same class。 For there is
no name common to all the objects that I mean； but； for all that；
these things are all in the same class by analogy。 Compare what
Empedocles says： They are one and the same； hair and leaves and the
thick wings of birds and scales that grow on stout limbs。） The fumes
of fat are a sooty smoke and those of oily substances a greasy
steam。 Oil does not boil away or thicken by evaporation because it
does not give off vapour but fumes。 Water on the other hand does not
give off fumes； but vapour。 Sweet wine does give off fumes； for it
contains fat and behaves like oil。 It does not solidify under the
influence of cold and it is apt to burn。 Really it is not wine at
all in spite of its name： for it does not taste like wine and
consequently does not inebriate as ordinary wine does。 It contains but
little fumigable stuff and consequently is inflammable。
All bodies are combustible that dissolve into ashes； and all
bodies do this that solidify under the influence either of heat or
of both heat and cold； for we find that all these bodies are
mastered by fire。 Of stones the precious stone called carbuncle is
least amenable to fire。
Of combustible bodies some are inflammable and some are not； and
some of the former are reduced to coals。 Those are called
'inflammable' which produce flame and those which do not are called
'non…inflammable'。 Those fumigable bodies that are not liquid are
inflammable； but pitch； oil； wax are inflammable in conjunction with
other bodies rather than by themselves。 Most inflammable are those
bodies that give off smoke。 Of bodies of this kind those that
contain more earth than smoke are apt to be reduced to coals。 Some
bodies that can be melted are not inflammable； e。g。 copper； and some
bodies that cannot be melted are inflammable； e。g。 wood； and some
bodies can be melted and are also inflammable； e。g。 frankincense。
The reason is that wood has its moisture all together and this is
continuous throughout and so it burns up： whereas copper has it in
each part but not continuous； and insufficient in quantity to give
rise to flame。 In frankincense it is disposed in both of these ways。
Fumigable bodies are inflammable when earth predominates in them and
they are consequently such as to be unable to melt。 These are
inflammable because they are dry like fire。 When this dry comes to
be hot there is fire。 This is why flame is burning smoke or dry
exhalation。 The fumes of wood are smoke； those of wax and frankincense
and such…like； and pitch and whatever contains pitch or such…like
are sooty smoke； while the fumes of oil and oily substances are a
greasy steam； so are those of all substances which are not at all
combustible by themselves because there is too little of the dry in
them （the dry being the means by which the transition to fire is
effected）； but burn very readily in conjunction with something else。
（For the fat is just the conjunction of the oily with the dry。） So
those bodies that give off fumes； like oil and pitch； belong rather to
the moist； but those that burn to the dry。
10
Homogeneous bodies differ to touch…by these affections and
differences； as we have said。 They also differ in respect of their
smell； taste； and colour。
By homogeneous bodies I mean； for instance； 'metals'； gold；
copper； silver； tin； iron； stone； and everything else of this kind and
the bodies that are extracted from them； also the substances found
in animals and plants； for instance； flesh； bones； sinew； skin；
viscera； hair； fibres； veins （these are the elements of which the
non…homogeneous bodies like the face； a hand； a foot； and everything
of that kind are made up）； and in plants； wood； bark； leaves； roots；
and the rest like them。
The homogeneous bodies； it is true； are constituted by a different
cause； but the matter of which they are composed is the dry and the
moist； that is； water and earth （for these bodies exhibit those
qualities most clearly）。 The agents are the hot and the cold； for they
constitute and make concrete the homogeneous bodies out of earth and
water as matter。 Let us consider； then； which of the homogeneous
bodies are made of earth and which of water； and which of both。
Of organized bodies some are liquid； some soft； some hard。 The
soft and the hard are constituted by a process of solidification； as
we have already explained。
Those liquids that go off in vapour are made of water； those that do
not are either of the nature of earth； or a mixture either of earth
and water； like milk； or of earth and air； like wood； or of water
and air； like oil。 Those liquids which are thickened by heat are a
mixture。 （Wine is a li