Friday evening the thirtieth was as dark as Erebus. Clouds had been boiling up since dark. Huge portentous masses rose on all sides and blotted out the skies. The air was for a time oppressively hot and still. The smoke from the guns which had wrangled during the day, long and loud, hung low; the smell of powder clung. The grey troops massed on Loudoun Heights and along the Shenandoah wiped the sweat from their brows. Against the piled clouds signal-lights burned dull and red, stars of war communicating through the sultry night. The clouds rose higher yet and the lightnings began to play. A stir began in the leaves of the far-flung forests, blended with the murmur of the rivers and became rushing sound. Thunder burst, clap after clap, reverberating through the mountains. The air began to smell of rain, grew suddenly cool. Through the welcome freshness the grey troops advanced beyond Bolivar Heights; there followed a long crackle of musketry and a body of blue troops retreated across the river. The guns opened again; the grey cannon trained upon the Maryland Heights; the Maryland Heights answering sullenly. Down came the rain in torrents, the lightning flashed, the thunder rolled. The lightnings came jaggedly, bayonets of the storm, stabbing downward; the artillery of the skies dwarfed all sound below. For an hour there was desultory fighting, then it ceased. The grey troops awaiting orders, wondered, "Aren't we going to cross the river after them?" "Oh, let it alone. Old Jack knows." Toward midnight, in the midst of a great access of lightning, rain, and thunder, fighting was renewed. It was not for long. The guns fell silent again upon Loudoun Heights; moreover the long lines of couching infantry saw by the vivid lightning the battery horses come up, wet and shining in the rain. From regiment to regiment, under the rolling thunder, ran the order. _Into column! By the left flank! March!_ A small stone hut on the side of a hill had formed the shelter of the general commanding. Here he wrote and gave to two couriers a message in duplicate. HARPER'S FERRY, VIRGINIA. May 31. Midnight. HON. GEORGE W. RANDOLPH, Secretary of War: Under the guidance of God I have demonstrated toward the Potomac and drawn off McDowell, who is sending Shields by Front Royal. Moving now to meet him and Fremont who comes from the West. T. J. JACKSON, _Major-General Commanding._ CHAPTER XXIV THE FOOT CAVALRY