HISTORICAL INTRODUCTION
Einstein's first paper on the restricted 'Theory of Relativity', originally published in the 'Annalen der Physik' in l905. Translated from the original German Papers by Dr. Meghnad Saha

Lord Kelvin writing-in 1893, in his prefaceto the English edition of Hertz's Researches on Electric Waves, says" many workers and many thinkers have helped to build up the nineteenth century school of plenum, one ether for light, heat, electricity, magnetism; and the German and English volumes containing Hertz's electrical papers, given to th

THE old saying that small causes give rise to great effects has been confirmed more than once in the history of physics. For, very frequently, inconspicuous differences between theory and experiment (which did not, however, escape the vigilant eye of the investigator) have become starting points of new and important researches.
Out of the well-known Michelson-Morley experiment, which, in spite of the application of the most powerful methods of exact optical measurement, failed to show an influence of the earth's movement on the propagation of light as was predicted by classical theory, there arose the great structure of Einstein's Theory of Relativity. In the same way the trifling difference between the measured and calculated values of black-body radiation gave rise to the Quantum Theory which, formulated by Max Planck, was destined to revolutionise in the course of time almost all departments of physics.

In this treatise I have tried to present in systematic and definite form a simple, rigorous, and thoroughly modem introduction to the fundamental principles of electromagnetic theory, together with some of the simpler of their more interesting and important non-technical applications.

THIS little book purports to serve as an introduction to the great problems of space, time and motion. The inquiries it is concerned with are very old. Men have been forming ideas concerning space and time since times immemorial, and curiously enough, have been writing and fighting about these things with the greatest interest, even fanaticism.

THE AIM of this book is to exhibit the scientific connexion of the various steps by which our knowledge of the phenomena of heat has been extended. The first of these steps is the invention of the thermometer, by which the registration and comparison of temperatures is rendered possible. The second step is the measurement of quantities of heat, or Calorimetry. The whole science of heat is founded on Thermometry and Calorimetry, and when these operations are understood we may proceed to the third step, which is the investigation of those relations between the thermal and the mechanical properties of substances which form the subject of Thermodynamics.

Near the beginning of his career, Einstein thought that Newtonian mechanics was no longer enough to reconcile the laws of classical mechanics with the laws of the electromagnetic field. This led to the development of his special theory of relativity. He realized, however, that the principle of relativity could also be extended to gravitational fields, and with his subsequent theory of gravitation in 1916, he published a paper on the general theory of relativity. He continued to deal with problems of statistical mechanics and quantum theory, which led to his explanations of particle theory and the motion of molecules. He also investigated the thermal properties of light which laid the foundation of the photon theory of light. In 1917, Einstein applied the general theory of relativity to model the large-scale structure of the universe.

In these days of numerous text-books the author who dares still further to increase the number owes to the public, at least, an explanation in which he shall set forth his purpose, however far short of accomplishment he may have fallen.

"Why did the apple fall out of the tree? Does everything fall? What makes things fall? Can anything stop things from falling? Are the sun, moon, and stars falling? Why don't they ever hit the ground?
So many questions. Newton spent many years answering these questions by thinking and doing experiments. He made up the law of gravity. According to this law everything pulled everything else to itself by a force called gravity. How strong that force is depends on how heavy the things are and how close together..
This book telling this excellent biographic story very simple, teaching and amazingly.."

The electrical problems of the present day lie largely in the economical transmission of power and in the radical improvement of the means and methods of illumination. To many workers and thinkers in the domain of electrical invention, the apparatus and devices that are familiar, appear cumbrous and wasteful, and subject to severe limitations. They believe that the principles of current generation must be changed, the area of current supply be enlarged, and the appliances used by the consumer be at once cheapened and simplified. The brilliant successes of the past justify them in every expectancy of still more generous fruition.

"I don’t want to bore you with the over and over told stories of the wave-particle duality and Schroedinger’s Cat…
May be there are hundreds of books that do this. But I tell you a different and deeply story so relation to the paralel universe that contain from ancient Upanishads to modern String theory and beyond with simply forming “Four Equations” and “Four Stories” in simple “Four Steps”.."
M. Ukray