— 73 — 



when they are to some extent soluble in water, may easily escape evap- 

 oration. In the case at issue the valuable citral would thereby be primarily 

 affected. It is certain that at 50° only a very small proportion of the 

 citral which has been dissolved in the water will evaporate. Therefore,, 

 too much water must not be used in diluting the peel -pulp. On the 

 other hand it is necessary that the boiling mass inside the still should 

 preserve a certain degree of fluidity in order that the inflowing steam 

 may set up an undulating motion in it. For this reason we only distilled 

 the thin upper layer of the peel, and not the entire peel — which would 

 have been simpler and less laborious — , because if the entire peel had 

 been used the increased mass of distilling-material would have required 

 the addition of a far larger proportion of water and would thus have kept 

 more citral in captivity. 



Possibly the above particulars may contain some useful hints for the 

 improvement of the Italian agrumi-'mdustry, but we feel it necessary to 

 call attention to another very characteristic difference between distilled 

 oil and hand-pressed oil. 



It is common knowledge that oils of lemon and orange can only be 

 kept in good condition for a very limited period, and that after some time 

 they acquire a foreign, acrid odour. If they have been kept in a corked 

 bottle, it will be found that the cork has been bleached pale yellow. 

 Protected from light and air the hand-pressed oils, owing to their wax- 

 like constituents, may be kept for more than a year, but not for several 

 years. It is different with the wax-free distilled oils; their keeping power 

 is much smaller. When the distillation has been conducted under atmos- 

 pheric pressure by means of water, that is to say at about 100°, the oil 

 begins to deteriorate after some weeks, or a few months. Oils of lemon 

 and orange which have been distilled at about 50° retain their pure odour 

 for a longer period, but, according to our experience, scarcely as long 

 as twelve months. 



Bergamot Oil. In the table below we present a symposium of the 

 characters of a series of bergamot oils which have been submitted for 

 our opinion within the past six months and which have proved to be 

 adulterated. 



Samples Nos. 1 to 5 contained added terpinyl acetate, in proportions 

 varying from 14% in No. 1 to about 3% in No. 5. With the exception 

 |of the sp. gr. of No. 1, which was too high, the constants of the samples 

 were generally within the limits of the values for pure bergamot oils; hence 

 the adulteration was only demonstrable after fractional saponification. 

 Sample No. 6 was also suspected of containing added terpinyl acetate, 

 and moreover, contained an ester belonging to the group of esters of 

 sparingly soluble acids, the saponification value of the evaporation-residue 

 and the difference between saponification value and acid value II being 



