Then the Doctor watched two utensils, in which, by a peculiar process, he sought to condense and harden carbon; he flattered himself with the hope of being able thus to obtain diamonds; but never was the result attained which his experiments should have given him. He consoled himself with a general observation. The hard coal becomes a diamond; strength of character alone creates great men, the sparkling jewels of mankind, but how seldom this process succeeds. Coal remains coal--with it the furnace only can be lighted. "While contemplating the immature diamonds, with a hopeless gaze, he heard his mother's voice in the study-- "Where is the youngster, then?" and she soon entered the laboratory, leading Olga by the hand. "Here is a lady visitor, dear Paul! Entertain Olga a short time, I will prepare a little supper for our dear guest." Fräulein von Dornau ventured boldly into the chemical _atelier_, where everywhere, right and left, as upon the Pharsalian fields in the classical Walpurgis night, little flames glowed, certainly not fairy-like will-o'-the-wisps, but little altar flames in the sacred temple of knowledge. Paul greeted her warmly, causing a glass to lose its balance and be scattered in pieces. "Sit down, Olga," said Paul, "we can talk here a little." And he cleared a place for her upon a bench. "Do not be afraid of this chattering workshop that talks of all the secrets of Nature. Do not be afraid of that which the elements tell, and if the gases and vapours of this witch's kitchen are not so sweet as the aromatic forest perfumes, it is yet just as much the breath of mother Nature, who here inhales it in somewhat deeper draughts than without in wood and field." Olga coughed slightly, because the sulphurous vapour oppressed her chest. "I have only to produce ozone out of these fugitive oils. Ozone--I rave about it; it is the genus of oxygen. Where it refuses the power of attraction to the latter, ozone can still work. That is the higher spirit or life! All passion is ozone; it is my element!" Olga, who had noticed that Paul was fond of imparting instruction, enquired as to the origin and nature of ozone, and in return, after a lengthy explanation, received praise for her daily augmenting thirst for knowledge. After the close of the lecture, and when several more experiments had taken place, Kuhl conducted his visitor into the study. "I have something important to tell you," said Olga, able to breathe once more in the airy room, the walls of which were covered with high bookcases reaching to the ceiling. "Go on," replied Paul, "one knows beforehand what seems important to you women; as a rule, they are the most insignificant matters in the world." "Not this--it concerns us all--you, too." "Tell it me, then." "Cäcilie, my sister Cäcilie--" "What about her?" "She is going to be married." "Impossible!" "It has become very possible since this morning, yes, almost certain."