Shares in Chloride have reacted with rise of more than 40% to the news that the power peripherals supplier has rejected an indicative cash bid approach from US rival Emerson worth 275p per share and £723m in total.Weir Group is posting more modest but impressive all the same gains after the engineer said it expects profits for the first half to be ahead of expectations after a strong first quarter.Fellow engineer Cookson is also strong after it said it expects trading profit for the first half of 2010 to be in the region of £110m to £115m, 15% to 20% above results in the second half of 2009.FTSE 250 - RisersChloride Group (CHLD) 297.30p +42.25%Weir Group (WEIR) 1,023.00p +9.29%Ashtead Group (AHT) 127.60p +9.06%Synergy Healthcare (SYR) 640.50p +8.01%Cookson Group (CKSN) 605.50p +6.51%IMI (IMI) 738.50p +6.41%Bodycote (BOY) 243.50p +6.33%Hansen Transmissions International (HSN) 101.90p +5.71%Fenner (FENR) 236.60p +5.39%Croda International (CRDA) 1,016.00p +4.69%FTSE 250 - FallersBritvic (BVIC) 486.20p -1.78%Carillion (CLLN) 350.80p -1.74%Salamander Energy (SMDR) 263.70p -1.60%SVG Capital (SVI) 167.70p -1.35%Hiscox (HSX) 339.20p -1.34%Hargreaves Lansdown (HL.) 376.30p -1.23%Berkeley Group Holdings (BKG) 870.00p -1.08%BSS Group (BTSM) 300.80p -1.05%easyJet (EZJ) 491.30p -1.05%WH Smith (SMWH) 505.00p -0.98%