Many attempts have been made to fraudulently make this congelation appear within the limits of temperature permitted, paraffine which dissolves well in rose oil being formerly frequently added. In such case the oil may congeal at from 65.75° to 68° F., but the crystals are opaque, dirty yellow, and dissolve to a turbid paste which collects on the surface. The simplest method is to distil white roses with the red. The resulting product has not as fine an odor as that from red roses alone, but is richer in stearoptene. Such oil, which, unadulterated, congeals perhaps at 68° F., can by the addition of geranium oil be reduced to from 63.5° to 65.75° F., thus keeping within the limits permitted. Numerous attempts have been made to find a rapid and sure way for the detection of geranium oil in rose oil, but thus far in vain. Attention must also be drawn to the fact that the adulterant is frequently itself adulterated with oil of turpentine before being sold to the distillers of rose oil. Besides the above-mentioned ginger-grass oil, the actual geranium oils from _Pelargonium odoratissimum_ and _P. roseum_, as well as rosewood oil, sandal-wood oil, spermaceti, paraffine, and fat oils have been mentioned as adulterants of rose oil. The geranium oils having a by-odor of lemon oil, by which their presence could be readily detected are not suitable for the purpose. Neither can rosewood or sandal-wood oils be used, or at least such adulteration would be so clumsy as to be immediately recognized. Attempts to adulterate rose oil by the addition of a fat crystallizable body together with another volatile oil fail on account of the characteristic properties of rose oil stearoptene, which resembles no other body at present known. While rose oil stearoptene is lighter than elæoptene and entirely volatile, spermaceti possesses essentially different qualities. It does not form such long and specifically light crystals as rose oil stearoptene; hence it readily separates on the bottom and on shaking exhibits a peculiar iridescent loamy formation. Furthermore it melts at 122° F., and not being volatile, leaves, on heating, a greasy stain upon paper, while the stearoptene melts at 95° F. and, on heating, volatilizes completely without leaving a greasy stain behind.