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
Being _twelve times lighter than common air_ it _rises_, and therefore
it would be better for ventilation to open the window at the _top_ than
at the _bottom_. But all gases exhibit a strong tendency to _diffuse
themselves_, and therefore they do not rise or fall in the degree that
might be anticipated.
67. _What proportion of hydrogen in the air is dangerous to life, if
inhaled?_
One-fiftieth part has been found to have a _serious effect_ upon
animals. The effects it produces upon the human system are those of
depression, headache, sickness, and general prostration of the vital
powers. It is therefore advisable to observe precautions in the use of
gas.
[Verse: "From the place of his habitation he looketh upon all the
inhabitants of the earth."--PSALM XXXIII.]
68. _What proportion of gas in the air may be recognised by the smell?_
By persons of acute powers of smelling it may be recognised when there
is _one_ part of _gas_ in _five hundred parts of atmospheric air_; but
it becomes very perceptible when it forms _one_ part in _a hundred and
fifty_. Warning is, therefore, given to us long before the point of
danger arrives.
69. _What other sources of hydrogen are there in our dwellings?_
It arises from the decomposition of animal and vegetable substances,
containing _sulphur_ and _hydrogen_. These give off a gas called
_sulphuretted hydrogen_, from which the fætid effluviam of drains
and water-closets chiefly arise. We should, therefore, take every
precaution to secure effective drainage, and to keep drain-traps in
proper order.
70. _May the use of gas for purposes of illumination be considered
highly dangerous?_
Not if it is intelligently managed. The appliances for the regulation
of gas are so very simple and perfect, that accidents seldom arise
except from neglect. In England 6,000,000 tons of coal are usually
consumed in the manufacture of gas, producing 60,000,000,000 cubic feet
of gas. And yet accidents are of very uncommon occurrence.
CHAPTER V.
71. _What is heat?_
Heat is a principle in nature which, like light and electricity, is
best understood by its _effects_. We popularly call that heat, which
raises the temperature of bodies submitted to its influence.
72. _What is caloric?_
Caloric is another term for heat. It is advisable, however, to use the
term _caloric_ when speaking of the _cause_ of heat, and of _heat_ as
the _effect_ of the presence of _caloric_.
[Verse: "While the earth remaineth, seed-time and harvest, and
cold and heat, and summer and winter, and day and night, shall not
cease."--GEN. VIII.]
73. _What is the source of caloric?_
The sun is its chief source. But caloric, in some degree, exists _in
every known substance_.
74. _What are the effects of caloric?_
Heat which, in proportion to its intensity, acts variously upon all
bodies, causing _expansion_, _fusion_, _evaporation_, _decomposition_,
_&c._
75. _Why is caloric called a repulsive agent?_