SUMMARY
By the late 19th century, despite the fact that the
phenomenon of current flow had not been fully explained, most known
electric phenomena were successfully described by physical
formulae.
It was already possible
to measure quite accurately the charge of an insulated object, the
intensity of current flowing in a wire connected to a battery, or
to calculate the forces acting on a known charge placed at a known
distance from another charge (Coulomb's law). It was possible to reckon
the magnetic field in the vicinity of a conductor with current and
the force acting on the conductor through which current flows and
which is placed in the magnetic field. They learnt how to reckon
current induced in a wire coil placed in a variable magnetic field.
They also knew how to calculate the charge which could accumulate
on an insulated conductor connected to a battery of a potential
that was higher than the potential of the conductor.
Actually this knowledge
had been acquired by scientists since mid 19th century. It enabled the development of many
branches of technology. However, at that time a single model of the
structure of electricity did not exist. Only purely empirical
methods enabled scientists to gather so much information on
electricity.
Certainly there were
attempts at the creation of those models. A decisive majority of
scientists considered the flow of current to consist in a flow of
some substance in the conductor. However, researchers differed on
whether there was one, or two different "liquids". The first of
those concepts assumed that there was a substance, a definite
amount of which renders a body neutral, surplus makes it positive
and shortage - negative. The other concept assumed the existence of
two different "liquids" - a positive and a negative one. Both
models explained the known electric phenomena equally well.
Another big unknown was
the structure of electricity. Some scientists shared the view that
it was infinitely divisible (the liquid model) whereas others
considered it to be in granular, molecular form.
Cathode rays phenomenon was equally strange and
provoked as much controversy. Scientists managed to examine and
determine many of their properties like: deflection in a magnetic
field, phosphorescence of glass of vacuum tube where the beam
falls, the phenomenon of their perpendicular emission in the
relation to the cathode, occurrence of certain photochemical
reactions under the influence of the rays. It was shown that those
rays transmitted energy and the direction of their divergence did
not need to follow the direction of the current field in the vacuum
tube. Also diffusion of rays through thin metal foils was observed.
During researches of this phenomenon two theories emerged
explaining their properties: one supported corpuscular and the
other undulatory nature of rays. Behaviour of the rays in a
magnetic field would be explained by the assumption that they
constituted of molecules of negative charge. However such charge
failed to be discovered. Schuster only managed to estimate
that if rays actually consisted of negative molecules, their charge
to mass ratio could not be less than 5*106 coulombs per
kilogram nor more than 1010 coulombs per kilogram.
Scientists boasted
numerous achievements in the field of the research of matter. Since
the early 19th century occurrence of
numerous chemical phenomena had been explained by references to the
atomic theory. They managed to show that the whole variety of
substances existing in nature actually consists of a small number
of elements. Considering their properties, those elements can be
arranged into a table - the Mendelejev's periodic table.
Moreover, scientists managed to figure out many laws and
relationships governing the microcosm. They formulated basic laws
of thermodynamics and laws describing the ideal gas. They learnt
how to determine the mean distance covered by gas molecules between
collisions. Also behaviour of actual gases was profoundly
researched.
By the end of the
century new elements were discovered, the existence of which was
predicted by the Mendelejev's periodic table. All
elements of the puzzle started to fall into place. The world was
made of elements, of which an uncountable number of substances
consisted of and which were the smallest components of the matter.
It seemed to scientists in 1894 that the final solution of few
remaining secrets of nature was the matter of a few coming
years.
However, that was not
the case. Scientists only made their first step on the way to
explain mysteries of the microcosm. They discovered much but even
more remained to be discovered.
