226 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1911. 



The process of producing reconstructed rubies by means of the 

 oxy-hydrogen blowpipe is, roughly, as follows: The residue from 

 cutting rubies and small worthless stones is broken into coarse sand, 

 a small quantity of which is placed on the center of a disk of platinum; 

 this is then carefully brought to the fusion point, care being taken 

 at this stage not to raise the temperature to such an extent as to 

 melt the platinum support. As soon as this mass is fused it serves 

 to protect the platinum, and the reconstructed ruby can be built 

 up on it by adding the fragments of ruby one at a time by means of 

 small platinum forceps. These pieces have to be dropped on with 

 great care in order to secure incorporation with the mass and pre- 

 vent as far as possible the formation of air bubbles. It will be readily 

 understood that this process is a tedious and laborious one, and, in 

 fact, the formation of masses of sufficient size to yield large stones 

 on cutting is a matter of such difficulty that the cost of production 

 is very high. 



Just about seven years ago, however, Vcrneuil * overcame this 

 restriction when he hit on the extremely ingenious idea of intro- 

 ducing the raw material through the blowpipe, and thus placing 

 it on the support automatically. The diagram (pi. 2, fig. 1) shows 

 the principle of his apparatus. The blowpipe is arranged vertically 

 over a small insulated chamber containing the support on which the 

 mass is to be built up. The oxj^gen tube communicates at its upper 

 extremity with a funnel-shaped hopper, in which is suspended a 

 small sieve filled with the raw material, which is rhythmically shaken 

 by means of a small hammer actuated by an electromagnet or cam. 

 Each time the hammer taps the support of the sieve, causing it to 

 vibrate, a small quantity of the powder falls through into the tube 

 below, and, carried along by the gas, passes out at its lower extremity 

 into the zone of flame, where it is immediately raised to the fusion 

 point, and falls as a melted globule on to the support below. 



As seen in the diagram, this support is arranged with a screw 

 adjustment, so that as the mass of corundum is gradually built up 

 by the constant addition of fresh globules the surface can be kept 

 at a constant level, and the portion already formed removed from 

 the zone of heating so as to allow it to stiffen. When the apparatus 

 is first started the blowpipe is adjusted so as to give a comparatively 

 cool flame, and the powder is admitted slowly. By this means a 

 small "stalk" is formed, which insulates the mass from the support 

 and prevents the fusion of the latter. When this has been formed 

 the full pressure of the blowpipe is put on and the rate of admission 

 increased, with the consequent formation of a "boule," as it is 

 termed, having the shape of a pear, as illustrated in plate 2, figure 2 f 



» "Memoire sur la reproduction artificielle du rubis par fusion," M. A. Verneuil, AnnaJes de Chimie ct de 

 Physique, September, 1904. 



