126 



TERMINOLOGY. 



iments of the chemist, where the blowing must often be sustained for 

 several minutes at a time, a considerable embarrassment is experienced 

 from this source. Inendeav- 



oring to avoid this, as well as Fig. 152. Fig. 153. Fig. 154. 

 with a view to render the in- 

 strument more portable, sev- 

 eral variations have been adop- 

 ted in its construction. One 

 of these improvements is rep- 

 resented in Fig. 153 ; at 6, to- 

 wards the center of the blow- 

 pipe, the tube enlarges into a 

 ball, three fourths of an inch 

 in diameter, in which the 

 moisture from the mouth ac- 

 cumulates, and is removed, 

 occasionally, by being un- 

 screwed at its centre and care- 

 fully wiped out. This instru- 

 ment is made of brass, and 

 furnished with a mouth piece 

 a, of ivory. Another form, 

 Fig. 154, and the one to which 

 the preference is given, was 

 introduced by Voigt. It has 

 the chamber or barrel c, for 

 the reception of moisture, sit- 

 uated at the angle of the in- 

 strument near the beak : it is 

 circular in its form, one inch 

 in diameter, and one eighth 

 of an inch across. The beak 

 issues from the centre of this 

 chamber, and is capable of being turned completely round. Upon its 

 extremity is fitted a little appendage d, pierced with a hole more or less 

 fine, through which the air escapes. Three or four of these little cones 

 accompany the instrument of different calibres, which can be substitu- 

 ted for one another at pleasure. Berzelius recommends that they bo 

 made of platina, as in using them for a little time, they become coated 

 with lampblack, and if made of this metal are at once cleansed by heat- 

 ing them to redness upon charcoal before the blowpipe. This blowpipe 



