SIR, - In your issue of Wednesday I read in "Notes and Queries" that Mitre-square has "criminally-historic" associations. "C.C." gives three incidents. I concur with him in two, but the last, which reads thus, "Twenty years ago two men blew up a house in the square," was not a criminal act, but the result of a pure accident. Permit me to briefly give particulars of the event. The house was No. 7 (site now occupied by warehouses), and stood in a south-east position, then occupied by a Mrs. Simmonds, who used to let the upper part as furnished apartments. The first floor was let to two foreigners, who at the time were experimenting with some material of an explosive nature, when one of them struck a match to light a cigar, and carelessly threw it down, and, coming into contact with the inflammable combustion, exploded, set fire to the house, the interior of which was destroyed, and the two unfortunate men lost their lives. The charred remains were placed in St. James's Church (which then stood immediately opposite) awaiting burial. Being a resident in the square at the time, I can substantiate the above facts. - I am, &c,