The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million — John Stuart Mill — John Shaqi
The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million
John Stuart Mill · en
Because its chief effects are to _expand_, _fuse_, _evaporate_, or
_decompose_ the substances upon which it acts.
76. _What is an attractive agent, in contradistinction to a repulsive
agent?_
Chemical attraction, or affinity, is an attractive agent--as when
bodies seek of their own natures to unite and form some new body.
77. _When is a body said to be hot?_
When it holds so much _caloric_ that it diffuses heat to surrounding
objects.
78. _When is a body said to be cold?_
When it holds less _caloric_ than surrounding objects, and absorbs heat
from them.
79. _How may caloric be excited to develop heat?_
By any means which cause agitation, or produce an active change in the
condition of bodies. Thus friction, percussion, sudden condensation
or expansion, chemical combination, and electrical discharges, all
develope _heat_.
80. _Why do "burning glasses" appear to set fire to combustible
substances?_
Because they gather into one point, or _focus_, several rays of
_caloric_ as they are travelling from the sun, and the accumulation of
caloric developes that intensity of _heat_ which constitutes _fire_.
81. _What is a focus?_
In optics, it is the point or centre at which, or around which,
divergent rays are brought into the closest possible union.
[Verse: "Yet man is born to trouble, as the sparks fly upward.--I
would seek unto God, and unto God would I commit my cause."--JOB V.]
82. _What is fire?_
It is a violent chemical action attending the combustion of the
ingredients of _fuel_ with the _oxygen_ of the air.
83. _What are the properties of fire?_
It imparts heat, which has the effect of expanding both fluids and
solids.
It cannot exist without the presence of combustible materials.
It has a tendency to diffuse itself in every direction.
It cannot exist without oxygen or atmospheric air.
84. _What elements take part in the maintenance of a fire?_
Hydrogen, carbon, and oxygen. Hydrogen and carbon exist in the _fuel_,
and oxygen is supplied by the _air_.
85. _How does the combustion of a fire begin?_
A match made of phosphorous and sulphur (highly inflammable substances)
is drawn over a piece of sand-paper; the _friction_ of the match
induces the presence of _caloric_, which developes _heat_, and ignites
the match, the burning of which is sustained by the _oxygen_ of the
air. The flame is then applied to paper or wood, and the heat of the
flame is sufficient to drive out _hydrogen gas_, which unites with the
_oxygen_ of the air, and burns, imparting greater heat to the _carbon_
of the coals, which assumes the form of carbonic acid gas by union with
_oxygen_, and in a little while all the conditions of _combustion_ are
established.
86. _What are the properties of heat?_
It may exist without _fire_ or _light_.
It is not sensible to _vision_.
It makes an impression upon our _feelings_.
It acts powerfully upon _all bodies_.
It has no _weight_.
It attends, or is connected with, _all the operations of nature_.