This was the direct transformation of the solar energy locked up in coal into electrical energy, without loss either by waste or transference. How vast and yet easily controlled a power this would be in the hands of those who were able to wield it, may be guessed from the fact that, in the present day, less than ten per cent. of the latent energy of coal is developed as electrical power even in the most perfect systems of conversion.
All the rest is wasted between the furnace of the steam-engine and the dynamo. It was to electrical power, obtained direct from coal and petroleum, that Vladimir Romanoff trusted for the motive force of his air-ships and submarine vessels, and which he had already employed with experimental success as regards the former, when his career was cut short by the swift and pitiless execution of the sentence of the Supreme Council.
The remainder of this section was occupied by a list of chemical formulæ for the most powerful explosives then known to science, and minute instructions for their preparation. At the bottom of the page which contained these, there was a little strip of parchment, fastened by one end to the binding of the other sheets, and covered with very small writing.
Olga’s eyes, wandering down over the maze of figures which crowded the page, reached it before Serge’s did. One quick glance told her that it was something very different to the rest. She laid one hand carelessly over it, and with the other softly caressed Serge’s crisp, golden curls. As he looked round in response to the caress, their eyes met, and she said in her sweet, low, witching voice—
“Dearest, I have a favour to ask of you.”
“Not a favour to ask, but a command to give, you mean. Speak, and you are obeyed. Have I not sworn obedience?” he replied, laying his hand upon her shoulder and drawing her lovely face closer to his as he spoke.
“No, it is only a favour,” she said, with such a smile as Antony might have seen on the lips of Cleopatra. “I want you to leave me alone for a little time—for half an hour—and then come back and finish reading this with me. You know my brain is not as strong as yours, and I feel a little bewildered with all the wonderful things that there are in this legacy of my father’s father.
“Before we go any further, I should like to read it all through again by myself, so as to understand it thoroughly. So suppose you go to your smoking-room for a little, and leave me to do so. I shall not take very long, and then we will go over the rest together.”
“But we have only a couple more pages to read, sweet one, and then I will go over it all again with you, and explain anything that you have not understood.”
As he spoke, Serge’s eyes never wavered for a moment from hers. Could he but have broken their spell, he might have seen that she was hiding something from him under her little, white hand and shapely arm. She brought her red, smiling lips still nearer to his as she almost whispered in reply—