officer, by the name of Cronstedt, published his “Use of the Blowpipe in Chemistry and Mineralogy,” translated into English, in 1770, by Van Engestroem.  Bergman extended its use, and after him Ghan and the venerable Berzelius (1821).  The blowpipe most generally used in chemical examinations is composed of the following parts:  (Fig. 1.) A is a little reservoir made air-tight by grinding the part B into it.  This reservoir serves the purpose of retaining the moisture with which the air from the mouth is charged.  A small conical tube is fitted to this reservoir.  This tube terminates in a fine orifice.  As this small point is liable to get clogged up with soot, etc., it is better that it should be made of platinum, so that it may be ignited.  Two of these platinum tubes should be supplied, differing in the size of the orifice, by which a stronger or lighter current of flame may be projected from it.  Metals, such as brass or German silver, are very liable to become dirty through oxidation, and when placed between the lips are liable to impart a disagreeable taste.  To avoid this, the top of the tube must be supplied with a mouthpiece of ivory or horn C. The blowpipe here represented is the one used by Ghan, and approved by Berzelius.  The trumpet mouthpiece was adopted by Plattner; it is pressed upon the lips while blowing, which is less tiresome than holding the mouthpiece between the lips, although many prefer the latter mode.

[Illustration:  Fig. 1]

Dr. Black’s blowpipe is as good an instrument and cheaper.  It consists of two tubes, soldered at a right angle; the larger one, into which the air is blown, is of sufficient capacity to serve as a reservoir.

A chemist can, with a blowpipe and a piece of charcoal, determine many substances without any reagents, thus enabling him, even when travelling, to make useful investigations with means which are always at his disposal.  There are pocket blowpipes as portable as a pencil case, such as Wollaston’s and Mitscherlich’s; these are objectionable for continued use as their construction requires the use of a metallic mouthpiece.  Mr. Casamajor, of New York, has made one lately which has an ivory mouthpiece, and which, when in use, is like Dr. Black’s.

[Illustration:  Fig. 2]

The length of the blowpipe is generally seven or eight inches, but this depends very much upon the visual angle of the operators.  A short-sighted person, of course, would require an instrument of less length than would suit a far-sighted person.

The purpose required of the blowpipe is to introduce a fine current of air into the flame of a candle or lamp, by which a higher degree of heat is induced, and consequently combustion is more rapidly accomplished.