CALAMITOUS FIRE.-Yesterday a fire occurred or rather an explosion, at a house in Mitre-square, Aldgate which unhappily resulted in the violent death of two persons and in very serious injuries to a third, rendering his removal to a hospital imperative. The accident happened about half-past 11 in the morning at the house No. 7 in the square, in the occupation of Messrs. Cohen and Lavy, cigarette manufacturers, and it arose from the explosion of a quantity of Chinese fire, so called, which was stored on the premises. An explosion of some of the same inflammable material took place recently, as will be recollected, in the warehouse of Messrs. Price and Gosnell, perfumers, in the vicinity of Lombard-street, and resulted in a fire which did great damage, and for a time exposed to most imminent peril a vast mass of property of incalculable value in the banking quarter of the city of London. The explosion of yesterday occurred in a back room on the first floor used as an office, and the upper part of the house was burnt out, while the furniture and stock in other parts were seriously damaged by fire and water. Mr. Lavy, who was about 60 years of age, was burnt to death, as was also one William Hayman, a man of middle age. The former, we understand, was one of the partners in the firm, and Mr. E. Cohen, presumed to be the other partner, was very severely burnt. He is understood to have narrowly escaped with his bare life by jumping out of a window. He was taken to a hospital, where he still remains. The deaths of Mr. Lavy and Hayman are supposed to have been instantaneous. On the alarm being given at the Watling-street station of the London Fire Brigade, six engines, three of them being steamers, with 27 men, were dispatched to the spot and eventually extinguished the fire. At present it is not known whether the property was insured or not.