The case of Messrs HAMILTON and Sons v. the COWAN Patent Company to recover damages for an alleged breach of agreement in supplying the plaintiffs with heating apparatus, was again heard in the Exchequer Division of the High Court of Justice, before Barons CLEASBY and POLLOCK, on Friday.  The dispute was originally referred to an arbitrator, who decided that the plaintiffs were entitled to £500, but not allowing defendants anything for a claim of £280, made for the erection of the apparatus in dispute.  Mr. A.L. SMITH applied that the award be set aside, on the ground that certain evidence was not heard.  -- Mr. EDWARDS, Q.C., and Mr. Reginald BROWN were for the plaintiffs. -- Their Lordships decided that the award should be set aside.