Nothing is lost. Such a mighty flowing current cannot be stopped. If it rolls _in_ we may be assured that _somewhere_ it will roll _out_. And this is but THE GRAND COSMICAL CIRCUIT, already made mention of. FOOTNOTES: [D] We would not define cold as "absence of heat." Cold is rather the opposite electrical condition to heat. CHAPTER XV. WHY WAS NOT THIS DISCOVERY SOONER MADE? It may be asked, why should the discovery of this great source of all the forces, vital and physical, have been delayed to the present time? Master minds have been engaged for ages in efforts to solve the wonderful problem. HERSCHEL, NEWTON, HUMBOLDT, FARADAY, MOSSOTTI, and many others have held the _key_ almost within their control, and the consummation has only failed of being realized at an earlier day by reason of the tenacity with which the minds of men are held by preconceived and pre-existing opinions. SIR WILLIAM HERSCHEL regarded solar and stellar light as the effects of an _electro-magnetic_ process. NEWTON recognized all movements of the cosmical bodies to be the result of one and the same force; "_of some higher_ and _still unknown power_," but luminiferous ether shaded his mental vision, and he failed to discern that power. In his investigations of those great subjects he is led to ask, "Are not the sun, and fixed stars, great earths, vehemently hot?" HUMBOLDT said: "It is indeed a brilliant effort, worthy of the human mind, to comprise in one organic whole, the entire science of nature, from the laws of gravity to the formative impulse in animated bodies;" but the preoccupation of his vast mind, and the hold of pre-existing ideas, offered difficulties to the solution of the problem. But, note the approximation of his ideas to those herein expressed, he said: "The sun, as the main source of light and heat, must be able to call forth and animate magnetic forces on our planet." Unfortunately, however, he continues thus: "and more especially in the gaseous strata of our atmosphere." FARADAY, perhaps the most distinguished man, in the whole of his own field, which the world has ever produced, recognizing the power of this great obstacle to true advancement (_i. e._, preconceived and pre-existing ideas), once said: "When such a one as myself gets out of the way, then new conditions, new men, new views, new opportunities, may allow of the development of other lines of active operation than those heretofore in service." He believed in the existence of one great universal principle, from which gravity, heat, light, electricity, magnetism, even life itself might come. He spent many of his latest years in efforts to solve this great problem, and on his failure he asked: "Is it all a dream?" He never, however, wavered in his faith, and his last efforts were directed to that end.