— 8o — 



are not quite correct. In the distillation-material which for practical 

 purposes comes exclusively under consideration, viz., the blossoms of 

 Rosa damascena Miller, the same mixture of paraffins will always 

 occur, and the solidifying point will here consequently always corres- 

 pond to the stearoptene - content. This view agrees with present ex- 

 perience. If Jeancard and Satie apply their observations made on 

 other distillates to ordinary rose oil, it follows a priori that such a 

 conclusion is not convincing. 



Naturally, the solidification point alone cannot be accepted as 

 a standard of value for rose oil, but in conjunction with the deter- 

 mination of the other properties it will always be useful for judging 

 the value of the oil. 



For the purpose of valuing rose oil, F. Hudson-Cox and 

 W. H. Simmons 1 ) recommend the determination of the iodine number, 

 which is said to be here very serviceable. It is carried out in the 

 following manner; 0,1 to 0,2 gm. rose oil are diluted with 10 cc. 

 90 per cent, alcohol, and after adding 25 cc. of Hubl's iodine 

 solution, left standing for 3 hours at the temperature of the room. 

 The process is completed in the well-known manner. 



For a series of rose oils which are stated to be pure, and which 

 date from the years 1896 to 1903, Hudson- Cox and Simmons 

 determined as limits of value of the iodine number 187 to 194, 

 whilst the iodine numbers of the adulterants which come under con- 

 sideration are partly considerably higher. 



Whether the determination of the iodine number will be serviceable 

 for testing rose oil, is a question which must depend upon further 

 results. Up to the present this method, which is so useful for fatty 

 oils, had always failed in the case of essential oils, for obvious reasons, 

 and we do not therefore entertain much hope in this instance, the 

 more so as, according to Hudson-Cox' and Simmons' own state- 

 ments, the method is still capable of improvement in various respects. 



The discovery of small admixtures in rose oil is therefore still a 

 matter of difficulty, whilst in the case of coarser adulterations the 

 method of testing as hitherto carried out may be found sufficient. 

 We reserve a final opinion on the proposal made by Hudson-Cox 

 and Simmons, until their prospective further publications have made 

 their appearance. 



On the strength of numerous analyses made during the last few 

 years in our laboratories, we are in a position to correct and amplify 



*) The Analyst 29 (1904), 175; P]harmac. Journal 72 (1904), 861. 



