AA Fusion by the Hydro-orygen Blowpipe. 
parallel. The tube is then to be subjected to the wire-drawing 
apparatus, so as to compress the tube on its contents until the 
draught becomes so hard, as that it cannot be pushed farther 
without annealing. ‘The stuffed tube thus made is to be cut into 
segments, in lengths about equal to the diameter, by a fine saw. 
The surfaces of the sections are to be filed gently with a smooth 
file. By these means, they appear to the naked eye like the su- 
perficies of a solid metallic cylinder. Brass caps being fitted on 
these sections, they are to be interposed by soldering, at the dis- 
tance of a foot or more, into the pipe for supplying the jet. Un- 
der these circumstances, the posterior section becoming hot, may 
allow the flame to retrocede ; but the anterior section being be- 
yond the reach of any possible combustion, and remaining cold, 
will not allow of the retrocession ; and as soon as the flame passes 
the first section, the operator, being warned, will, of course, close 
the cock, and subject the posterior section to refrigeration before 
proceeding again. 
But this plan of operating may be rendered still more secut® 
by interposing a mercury bottle, or other suitable iron vessel, half 
full of oil of turpentine, between the reservoir and safety tubes, 
as in the arrangement of a Woulfe’s bottle. A leaden pipe pro- 
ceeding from the reservoir is, by a gallows screw, attached to an 
iron tube which descends into the bottle, so as that its orifice 
may be near the bottom. The leaden pipe communicating 
through the safety tubes with the jet-pipe, is attached to the ni 
of the bottle. Thus the gaseous mixture has to bubble through 
the oil of turpentine in order to proceed through the safety tubes 
to the jet-pipe. If, while this process is going on, the flame 
should, by retrocession, reach the cavity of the bottle, exploding 
in contact with the turpentine, a compound is formed, which 3s, 
per se, inexplosive from the excess of carbonaceous matter. 
Meanwhile the shock, acting on the surface of the oil, drives It 
into the bore of the iron tube, and thus, both by its chemical and 
mechanical influence, renders it utterly impossible that the flame 
should reach the cavity of the reservoir. 
Apparatus for the Fusion of Iridium or Rhodium or masses of - 
Platinum less than five ounces in weight. 
For the fusion of either Iridium or Rhodium or masses of Pla 
tinum not exceeding the weight of half an ounce, an instrume . 
with three jets has been employed, the bore of each Jet ae 
being such as not to admit a wire larger than the ;'; of an me" 
in diameter. The flame produced by these means was ss 
sufficient to envelope the mass to which it was applied. 
In fusing any lumps or congeries of platinum, not exceeding 
five ounces, an instrument has been used capable of giving sevem 
jets of gas, issuing of course, from as many pipes- Of thes? 
