[ r8o | 



Into it, wHich hinders the force of the wind'; Critf 

 ought therefore to have a piece of the fined wire, 

 to clear it with when required : And, in order to 

 have this wire the better at hand, it may be fatten- 

 ed round the Blow-pipe, in fuch a manner as is- 

 reprefented in fig. i. c is the wire, fattened round 

 the Blow-pipe at d. and afterv/ards drawn through 

 a fmall hole at e. made in the ring /. to keep it 

 more fteady. 



SECT. X. 



The Blow-pipe is compounded of two parts, 

 Tab. i. fig. 2. and 3 ; and this for the facility both 

 of making, carrying it along, and cleaning it on 

 the infide when it is wanted. 



In order to determine the mott convenient pro- 

 portions of this inftrument, feveral Blow-pipes of 

 different fizes, both bigger and fmaller, have been 

 tried : The former have required too much wind, 

 and the latter being too foon rilled with the wind, 

 have returned it back again upon the lungs : 

 Both thefe circumftances hindered greatly the ex^- 

 periments, and are perhaps even prejudicial to the 

 health. This fize, fig. x, is found to anfwer beft; 

 and though the hole mutt be r as fmall as before men- 

 tioned (Seel, ix.) yet the fides of the pipe at the 

 point mutt not be thinner, nor the point narrower 

 than here reprefented, elfe it will be too weak,, 

 and will not give fo s;ood a fiame. It is alfo to be 

 obferved, that the canal throughout the pipe, but. 

 particularly the hole at the fmall end, mutt be 

 made very fmooth, fo that there are no inequalities 

 in it •, the wind would elfe be divided, and confe- 

 quently the flame made double. That Blow-pipe- 

 is to be reckoned the belt, through which can be 

 formed the longeft and moft pointed flame from oft a 



common- 



