636 PROCEEDINGS OF THE AMERICAN ACADEMY. 



of the terminal orifice of the nozzle and to emerge below from the 

 bottom of the slot. The slot is then carefully stopped with a thin 

 metal plug P (slight projections from its surface prevent its being 

 forced inward too far), so that air can enter the tube through the ter- 

 minal orifice only. If this orifice is kept close to the under surface of 

 the wax plate, the melted wax will be completely withdrawn and will 

 run down into the glass bottle ; but if the orifice drops only a few milli- 

 metres below the under surface of the wax plate, the melted wax will 

 not be withdrawn and will soon congeal, leaving the cut edges firmly 

 reunited. This fact has been taken advantage of to produce at will 

 either a temporary or a permanent cut. As it would be inconvenient 

 to raise and lower the nozzle with its attached water reservoir, the slate 

 platform which supports the wax plate during cutting is made mova- 

 ble in a nearly vertical direction. The front edge (that next the 

 operator) is supported on two round-headed screws, — one seen dis- 

 tinctly near the dotted line a, Figure 2, the other faintly, close to the 

 detached " front plate-slide," further to the right. The height of the 

 front edge of the platform can thus be regulated by turning these 

 screws in or out, and accurate adjustment to the height of the fixed 

 nozzle thus secured. The middle of the far edge of the platform rests 

 on a square block (a, Figure 2) screwed to a long horizontal arm turn- 

 ing on a horizontal pivot at the left. Another horizontal arm (b) turn- 

 ing on a vertical pivot engages the slanting under side of the block, and 

 when moved in a certain direction raises the block some 6 or 8 mm. 

 This second horizontal arm is actuated by levers, not shown in the 

 figures, which are moved by the operator's knee. Thus the far edge 

 of the platform may be quickly raised or lowered at will, so that the 

 middle of the platform, where the heated wire is melting the wax, will 

 also be raised or lowered about half as much as the distant edge. 



To prevent the slate platform from becoming heated by the hot- 

 water tank below it, a felt lining is attached to its under surface and 

 a removable screen of the same material is placed over the tank. 

 This is seen at the left in Figure 2 — a square sheet with a square 

 notch cut out of one corner to accommodate the platform-block. 



As thus arranged, the wire may be readily heated to the desired tem- 

 perature, and, by operating the pedal as in sewing, it may be made to 

 make rapid vertical excursions. Since the wire is central to the orifice 

 in the copper tube, the wax plate may be moved in any direction, the 

 melted wax being withdrawn with equal facility, whatever the direction 

 of the cutting. The fine sharp cut, exactly perpendicular to the plane 

 of the wax, which is produced by this machine, seems to meet all the 

 requii'ements for cutting wax plates rapidly and accurately. 



