If the clock was to be put back, only the armed hand could do it, and that hand must be so armed that it could strike at first secretly, and yet with paralysing effect. The few would have to array themselves against the many, and if they triumphed, it would have to be by the possession of some such means of terrorism and irresistible destruction as those who had accomplished the revolution of 1904 had wielded in their aerial fleet. By far the most important part of this section of the will consisted of plans and diagrams of various descriptions of air-ships and submarine vessels, accompanied by minute directions for building and working them. Most of these were from the hand of Vladimir Romanoff, Olga’s father; but of infinitely more importance even than all these was a detailed description, on the last page but two of the section, of the solution of a problem which had been attempted in the last decade of the nineteenth century, but which was still unsolved so far as the world at large was concerned. 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.