BLOW-Pipe, in Chemistry and Mineralogy, an instrument by which the blast of the breath may be directed upon the flame of a lamp or candle, in such a manner as to vitrify any small portion of mineral substance; and thus the process of assaying in the dry way may be performed in a very short time, where either want of instruments or opportunity prevents other methods from being used.
Mr Bergman observes, that this instrument is extremely useful to chemists, as many experiments are daily neglected, either because they require furnaces and a large apparatus of vessels; from the want of time to examine them in the ordinary way; or from the quantity required in the common way for examination, when the matter may be too scarce or too dear. In all these cases the blow-pipe may be advantageously used; as, 1. Most of the experiments which can be performed in the large way may also be done with the blow-pipe. 2. The experiments which in the large way require many hours, may in this method be finished in a few minutes; and, 3. The smallest particle is sufficient. The only defect is, that the proportions cannot be determined with any precision; and therefore where the experiments can be tried on a large scale, it is always to be preferred. See CHEMISTRY and MINERALOGY Index.