9 



illumination. The thoria is first deposited upon some substance 

 such as cloth and so distributed that when the cloth burns away the 

 particles of thoria remain in the original shape of the mantle. When 

 held over the flame of gas or alcohol the particles become incan- 

 descent. To adjust an alcohol lamp for this purpose it is only neces- 

 sary to make an attachment whereby the alcohol is first converted 

 into a vapor. In order to light such a lamp a portion of the alcohol 

 must first be vaporized. 



In fig. 6 is shown an alcohol lamp, which is the property of the 

 Bureau of Chemistry. The illustration shows very plainly the 

 external mechanism of the lamp. The 

 knob on the right is the handle of the 

 pump, which brings a little of the alcohol 

 around the wick holder delivering the alco- 

 hol to the vaporizing chamber. This han- 

 dle is prest down two or three times by 

 the thumb, rising by means of a spring 

 to its original position. A few drops of 

 alcohol are pumped up and are ignited 

 by holding a match to the opening at the 

 handle or above. The alcohol burns with 

 a colorless flame for from thirty to sixty 

 seconds. By this time the chamber is hot 

 enough to volatilize the alcohol brought up 

 by the wick. The mill-head on the left is 

 then opened and the match applied at the 

 top of the chimney, when the alcohol vapor 

 ignites in the same manner as gas and soon 

 heats the thorium mantle, shown inside of 

 the chimney, to a white heat. The lamp 

 then burns regularly without any further 

 attention as long as any alcohol remains in 

 the bowl. 



In fig. 7 are shown two views of another 

 lamp, the principle of which is only slightly 

 different from that just described. The 

 lamp on the left is cut away in order to show 

 the internal mechanism. The alcohol is fed by the wicks D to the 

 copper vaporizer A placed under the mantle. The burner C is sup- 

 plied by a Bunsen burner B placed beneath it and having its output 

 regulated by means of a needle valve attached to the regulator button 

 E. A small lateral aperture F permits of the introduction of a ball 

 of asbestos saturated with alcohol for starting the vaporization at 

 the moment of lighting. 



8992 No. 26906 2 



FIG. 6- Alcohol lamp with pump 

 attachment. 



