40 KEFOET — 1865. 



neighbourhood of Bandoug were therefore almost useless, he thought it interesting 

 to make some experiments on the preparation of the essence of shaddock flowers. 



After a great many distillations of several hundred-weights of fresh flowers, the 

 result was that the average quantity of essence yielded by 1000 lbs. weight of fresh 

 flowers was 1 lb. 



Having ascertained the amount of product, the following question arises : — Is 

 the essence obtained by me from the petala of the shaddock trees identical with the 

 essence of orange flowers called neroli ? The result of his experiments in this 

 direction was, that the two essences are really identical, which conclusion was 

 afterwards confirmed upon his return to Em-ope, by the principal manufacturers of 

 perfumes whom he consulted on this subject, and who declared the essence of 

 3haddock flowers prepared by him to be identical with first-rate quality of neroli. 



Another question of importance also arises: — Would the manufacture of neroli 

 in the tropical countries pay ? This can only be answered by practical experience. 

 In Java, where the author made his experiments, the local circumstances are such 

 that the manufacture woidd certainly pay. 



But besides the neroli obtained by distillation of the flowers, there remains in 

 the still after the distillation a substance which deserves attention, if ever his plan 

 of preparing neroli in the tropical colonies should be carried out. If the residue 

 in the still is thrown, yet boiling, upon a cloth, the clear yellowish liquid which 

 passes through the cloth deposits after a few days a large amount of yellow crystals. 



His experiments with these crystals have proved that they are identical with the 

 substance discovered in 1828 by Lebreton in unripe bitter oranges, and called by 

 him " hesperidine." This hesperidine, which the author finds very widely spread 

 in the genus Citrus, is the pure, bitter substance contained also in orange peels. 

 As this hesperidine is a pure and quite innocent bitter substance, which can be 

 obtained easily, and in tolerably large quantities from shaddock flowers, it deserves, 

 perhaps, attention as a substitute for hops. 



On the Rotatory Power of several Essential Oils. By J. E. be Vkij. 

 The author communicated the results of his experiments on the rotatory power 

 of more than ninety specimens of different essential oils. He observed them in a 

 tube of 100 millimetres length with Biot's polarizing apparatus, and although he 

 found a great discrepancy in the rotation of specimens of the same essential oil pre- 

 pared in different localities, he considers, nevertheless, the accurate determination 

 of this physical property of great importance for the study of these still very im- 

 perfectly known compounds. In observing, for instance, the rotation of seventeen 

 specimens of the essence of peppermint manufactured in England, France, Ger- 

 many, Holland, and America, by well-known manufacturers, he found thirteen 

 specimens showing a rotation to the left, varying between^— 6° and —34°, three spe- 

 cimens showing a right rotation varying between +9° and +10 o, 5, and one speci- 

 men which showed no rotation at all. It appears therefore that the essence of 

 peppermint is a mixture of at least two essences, one of which has a right and the 

 other a left rotation, which explains the difference, and also the absence of rotatory 

 power in different specimens. In examining the rotatory power of French and 

 American essence of turpentine and of their compounds with hydrochloric gas, he 

 observed the singular fact that, though both the essences showed a left rotation, the 

 solid and liquid camphor obtained by hydrochloric gas from the American essence 

 showed a right rotation, whilst those compounds obtained from the French essence 

 retain the original left rotation of the essence from which they are prepared. 



W. White exhibited Photographs of the Interior of the Great Pyramid taken 

 with the Magnesium Light by Prof. C. Piazzi Smyth. 



On the Aniline Process in Photography. By W. Wielis. 



Cn the New Formula', with reference to ScJiools and Examinations. 

 By Dr. T. Wood. 

 Br. Wood said he wished to call the attention of the Section to a matter which 



