 Complete the following phrase:  For the next attack, the Battle of the Selle, IX Corps HQ selected important localities to be bombarded by 70th Siege Btys heavy howitzers, for which 200 rounds of ammunition per gun were accumulated. The corps attacked on 17 October, lifted forward by two great belts of intense artillery fire, and a German counter-attack was hit by every gun within range. IX Corps renewed its advance on 23 October, with 12th Bde part of a massive corps artillery reserve. The attack went in at 01.20 in moonlight, after the heavy guns had done the usual CB and harassing fire bombardments, and the results were extremely satisfactory. After a pause to regroup and reconnoitre, IX Corps stormed across the SambreOise Canal on 4 November the 