MAY 25 1938

ON THE TEMPERATURE AND STRUCTURE OF THE

SUN.

BY

O. LUMMER.

Address delivered by invitation before the Philosophical Society of Washington, March 21, 1907.

Twenty years ago, while traveling on the Mediterranean to the Holy Land, I met a number of American clergymen, sent there by their churches, and I had occasion to listen to their sermons. They told their hearers of God's almighty power and goodness, and illustrated by accounts of what they had seen in traveling around the world. The beautiful ocean, the brilliant blue sky, the lovely Italian country, all nature and its creatures, must impress upon us the idea of God, who governs all things. If such a superficial observation of nature brings us nearer to an eternal being, how much more must the scientific man, who examines more closely into the play of forces in God's universe, really appreciate their power and scope. Indeed, only the learned man of natural science reaches a conception of God in all its full

ness.

The modern school of naturalists, and especially physicists, has little of the exaltation of our HAECKEL. Our knowledge of things has been reduced to the standpoint of DU BOISREYMOND'S "Ignoramus et Ignorabimus." Indeed, when we ask ourselves what the aim of natural science is, we must answer: It is to study, not what is beyond the conceivable, but the laws of nature, to classify objects and phenomena outside ourselves, and to find the relations between effects and causes. Thus only do we become masters of the natural forces and turn them to the profit and benefit of mankind. Thus is blind idolatry replaced by adoration of the general 12-Bull. Phil. Soc., Wash., Vol. 15. (75)

laws of nature, and of the Creator of all these wonders. To bring new phenomena and their producing forces within our established knowledge we have really not to explain, but to formulate them. Do you really know that our earth revolves about the sun, and why they attract each other according to Newton's law? We can never really know this, and indeed we shall consider ourselves fortunate when we shall have found that the Newtonian attraction requires time to influence an attracted body. We cannot know much about the real causes of natural forces; nevertheless we already know much about their laws.

According to Herman VON HELMHOLTZ, our human natures must have believed a priori that the processes in nature are regularly and logically ordered and connected to each other by laws, or we would never have had the courage to undertake tedious and difficult research work. At the end of a long period of experimental work we feel confident in the relations which have been found to connect the observed phenomena. In order to reach the high standpoint to which natural science has brought us, we have had to abandon the old fashion of thinking out at the writing desk the mysteries of the world. In spite of Goethe's sentence, "Und was sie Dir nicht offenbaren will, Das zwingst Du ihr nicht ab mit Hebeln und mit Schrauben," we have succeeded in finding the natural laws only by experimental study, by asking Nature questions and by compelling her to answer. Not long ago this manual labor "was completely scorned." It will interest you to know that Helmholtz's father, a Potsdam theologian, ridiculed his famous son, when he became a student of natural science, for entering so unworthy a profession. It was not until the son was twenty-seven years old and a full professor of anatomy at Königsberg, and earning more money than the old man, that father Helmholtz became reconciled to the research work formerly so heartily despised by him.

At the present time salaries are paid by governments for research, and if they are not sufficient to make us wealthy, we get enough money to live upon, and, what is still more