SULPHURIC-ACID, the name adopted by the French chemists for the vitriolic acid. It is formed by a combination of sulphur with vital air, as described under the article SULPHUR. When sulphur is buried with a low degree of heat, it burns with a blue flame, and diffuses a suffocating vapour, which, when collected, is called sulphureous acid. When sulphur is exposed to strong heat it burns rapidly, and emits a lively white flame, and has no smell; the residue is called sulphuric acid. The sulphureous is a weaker acid than the sulphuric, owing to its containing a less quantity of oxygen.