— n6 — 



(cyclogeraniolene). This body — contrary to analogous derivatives with 

 open chain and those of the aromatic series — is attacked by water 

 only with difficulty. Further, cyclogeraniolene does apparently not 

 react with one molecule ozone (0 3 ), but, according to Harries and 

 Weil, with 4 , as the body on analysis showed the composition 

 C 9 H 16 4 , and the cryoscopic determination showed the double mole- 

 cular volume. According to a new work by Harries and Neres- 

 heimer 1 ) the same takes place in lower homologues of cyclogeraniolene; 

 but with tetrahydrobenzene the values ascertained for the ozonide still 

 corresponded more or less with those calculated for the normal com- 

 pound. Tetrahydrotoluene already behaves like cyclogeraniolene. Tetra- 

 hydrobenzene ozonide has probably the composition C 6 H 10 O 3 ; 

 when split up with water, it yields little adipic dialdehyde and 

 much adipic acid, m. p. 148 to 149 . m-Dihydroxylene diozonide, 

 (CH 3 ) 2 C 6 H 6 (0 3 ) 2 yielded only on reduction with aluminium amalgam 

 in ethereal solution, levulic aldehyde, b. p. 77 to 8o° (15 mm. pressure). 



Bibliographical notes. 



J. W. Bran del 2 ) has completed his abstracts on the volatile oils 

 in 1904, and commenced a report on the publications in this domain 

 during the year 1905. We would not fail to call attention also to 

 these continuations. 



Analytical notes. 



For the determination of citral in lemon oil, a whole number of 

 methods 3 ) has already been recommended, of which, however, not one 

 has up to the present been found to answer in practice, as they all 

 give results which are not so accurate as is required in view of the 

 small quantity of citral contained in lemon oil. Now, a method has 

 recently been published by Edward Mac Kay Chace 4 ), which is 

 said to be very useful for the estimation of small quantities of citral. 

 It is based on the property of fuchsin sulphurous acid of acquiring 

 a red colour in the presence of aldehydes, and that more or less 

 strongly according to the quantity of aldehyde present. By means of 

 comparative tests with solutions of a known aldehyde-content, the 

 quantity of the latter in the oil to be examined is ascertained. 



*) Berl. Berichte 39 (1906), 2846. 



2 ) Pharm. Review 24 (1906), 112, 149, 317, 344, 375; 25 (1907), 5 8 J com P- 

 also Reports April 1906, 10 1, and October 1906, 102. 



3 ) Reports April 1900, 22, October 1900, 25, April 1901, 47, October 1904, 

 121, April 1905, 35, October 1905, 29. 



4 ) A method for the determination of citral in lemon oils and extracts. Journ. 

 Amer. chem. Soc. 28 (1906), 1472. 



