[ 3*3 3 
SECT. LV. 
The life of the Pocket-Laboratory, as here de- 
fcribed, is chiefly calculated for a travelling mine- 
ralift. But a perfon who is always refiding at 
one and the fame place, may by fome fmall altera- 
tion make it more commodious to himfelf, and 
avoid the trouble of blowng with the mouth. 
For this .purpofe he may have the Bfow-pipe 
go through a hole in a table, and fixed under- 
neath to a fmall pair of bellows with double bot- 
toms, fuch as fome of the glafs- blowers ufe, and 
then nothing more is required, than to move the 
bellows with the feet during the experiment ; but 
in this cafe a lamp may be ufed inftead of a candle. 
This method would be attended with a ftill greater 
advantage, if there were many fuch parts as fig. 3. 
tab. I. the openings of which were of different 
dimenfions : thefe parts might by means of a fcrev/ 
be faflened to the main body of the Blow-pipe, and 
taken away at leifure. The benefit of having thefe 
nozzles, if I may be permitted to call them fo, of 
different capacities at their ends, would be that of 
exciting a ffronger or weaker heat as occafion 
might require. It v/ould only be neceffary to ob- 
fprve, that in proportion as the opening of the pipe 
(nozzle) is enlarged, the quantity of the flame 
muit be augrnented by a thicker wick in the lamp, 
and the force of blowing increafed by means of 
weights laid on the bellows^ A much intenfer 
heat would thus be procured by a pipe of a confi- 
derable opening at the epd, by which the experi- 
nients might undoubtedly be carried farther than 
with the common Blow-pipe, 
SECT, 
