LOCKOUT by Leon Wolff. 297 pages. Harper & Row. $5.95.
On a hot July morning in 1892, a tug chugged up the Monongahela, towing two barges with a deadly cargo: 300 pistols, 250 Winchester rifles and a hired army of 316 Pinkerton men. Where Andrew Carnegie's Homestead mill sprawled along the south bank of the river, the barges beached. That was enemy territory, defended by a cannon, spiked clubs, small arms, and a force of strikers 10,000 strong. Hostilities began at once. One fusillade from the barges dropped 30 defenders, but not one Pinkerton got ashore. Homestead's striking mill hands had won...