The St. Louis Reporter of the 18th inst. relates the following most melaucholy occurrence : 'On Satimlay evening, about eight n'clock, as a yoting girl, an orphan, residing in the iamily of Mr. Fttrnham, on Oreen street, was in the act of filling a lamp with spirit gas, the inflammal)le substanceexploded, causing a report that was hoard several squares distant. The untortuiiale girl was immediately wrapped in liamcs, and the curtains, cnrpet nnd table covers of the roum set on fire. Two children of Mr. Farnham, one about two, and the Ã¶iher four years of age, werÃ© in the room at the time. The girl, on the occÃ¼rrencoof the accident, threw herself on the Hoor, and endoavored to extinguish the fire by ga'hering around her the carpet. Unfortunately the alarrned children rushod towards her, when their clothes look fire. ThÃ© three were so dreadfully burned that they all dled before moriing. Mr. Murphey, who lives adjacent, rushed into ihe apartmenl at the firsi alarm, and succeeded in extingiiishsng tlic firÃ¨, thotigh ho himself is badly burned.