116 EXPERIMENT STATION RECORD. 



drying was begun at the lower temperature and then gradually raised to 145°, 

 at which temperature it was held as nearly as possible until the hops were 

 dried. The temperature was taken with thermometers which were kept just 

 under the floor of the kiln and at that portion of the kiln where the tempera- 

 ture was highest." The kilns employed were, with one exception, ordinary 

 stove kilns, and were representative of those in common use. Comparisons 

 were made with samples of hops which were air dried at room temperature. 

 The determinations made were water, total resins, hard (gamma) resin, beta 

 resin, alpha resin, tannin, and wax. 



" The results indicate that there was little if any change in the composition 

 of the hops during the kiln-drying process. It will be noted that [with the 

 exception of 2] samples, the amount of hard resin is slightly greater in the air- 

 dried samples, a result which may be due to the variation In different samples. 

 There was evidently little If any change in the amounts of tannin and wax, 

 considering the possible -variation in separate samples. A physical examination 

 showed that the difference in the aroma of the air-dried and the kiln-dried 

 samples was hardly perceptible, different judges varying somewhat in their 

 opinions.'' 



See also previous work (E. S. R., 27, p. 814). 



Notes on expressed and distilled West Indian lime oils, H. A. Tempany 

 and N. Greenhalgh {West Indian Bui., 12 {1912), No. 4, pp. 498-503) .—This 

 gives the results of examining 7 samples of hand-expressed oils and 3 of dis- 

 tilled oils, in which were determined the specific gravity at 30° C. the optical 

 rotation In a 100-mm. tube at 31°, the refractive index at 32°, the citral content 

 by Burgess and Child's method, and the acid value by titration of 5 cc. of the oil 

 dissolved in alcohol with seminormal alcoholic potash in the cold. 



In regard to the expressed oils, the results show a somewhat wider divergence 

 between the character of the different oils than is indicated by various author- 

 ities. The values for the optical rotation are lower than would be expected, 

 probably because of the expansion of the oil owing to the high temperature at 

 which measurements were made. The citral content and the acid number 

 showed a fairly close correlation but varied markedly in different samples. 

 The citral determination seemed to give satisfactory results. The amount of 

 citral found varied markedly in the different samples, but was lower than is 

 found in lemon oils, which, according to Gildemeister and Hoffman, contain 

 from 7 to 30 per cent of that constituent. 



With regard to distilled oils, the samples appeared to be characterized, on 

 the whole, by a lower refractive index, citral content, and acid number, and 

 in some cases a lower specific gravity. The rotiition, on the other hand, was in 

 all cases somewhat higher. 



" From the above results, it would appear that during the process of dis- 

 tillation with steam (the conditions under which ordinary distilled oil is ob- 

 tained being practically those of a steam distillation) a certain proportion of 

 the lower and higher boiling constituents are removed. The blue fluorescence 

 due to the presence of a crystalline substance in the higher fractions of the 

 expressed oil is entirely absent in those of the distilled oils. This substance 

 possibly may be the anthranilate which is known to exist in lime oil (Allen), to 

 the methyl ester of which, C6H4(NH.CH3).COOCH3, E. J. Parry « ascribes 

 the blue fluorescence of mandarin orange oil. This is probably removed during 

 the steam distillation. 



" Expressed oil on standing generally deposits a pale yellow crystalline sub- 

 stance known as limettin. Distilled oils do not deposit this body. Limettin is 



•Allen's Organic Analysis, 2 (1907), pt. 3, p. 40. 



