nearly four o'clock
His hand and arms were badly burned with the acid , and there were splashes of it on his face . The masters were doing what they could to get the deadly poison out of his lungs , but it seemed as though Horace and the third lad had inhaled so much of the gas that all their efforts were in vain . The doctor looked grave when Mr. Skeats told him the boys had been breathing hydro-cyanic acid gas . The application of artificial respiration was redoubled , but it was not until nearly four o'clock that Horace began to revive , and what Leonard felt during those awful hours of suspense could be better imagined than described ! The laboratory had been locked up , as soon as it was known what had happened , so that the affair might be inquired into . No boy was allowed to go home either , although Taylor had complained of being very ill , and had wanted to leave early . Not until it was known that Horace was out of all immediate danger was there a word spoken , and then Dr. Mason said , ` I am ready to hear any explanation that you may wish to give me as to the cause of what has happened .