388 CJironicles of Science. [July, 



Bennett describes an edible plant, Ahtonia edulis, found in New 

 Caledonia — the natural order to which the Tanghina Poison-tree of 

 Madagascar belongs — as also the Strychnos, or Nux vomica, and the 

 Oleander ; the same order, on the other hand, includes the useful 

 Hya Hya, or Milk-tree, of Demerara (Tdbsmsemontana) , the Cream- 

 fruit-tree of Sierra Leone (Roupellia), and many others. The 

 Ahtonia edulis is a climbing plant, the fruit-pods of which are 

 much used in New Caledonia both by natives and Europeans as an 

 esculent vegetable. Another species of Ahtonia, which is of con- 

 siderable use dietetically, is the A. constricta. It is the Bitter Bark- 

 tree of the colonists, and was supposed at one time to have the 

 properties of Quinine. It really, however, more closely resembles 

 Quassia, and is used as a tonic and for preparing " bitters." Dr. 

 Bennett directs attention to the desirability of cultivating both these 

 plants with a view to their economic applications. Mr. J. F. 

 Wilcox has sent samples of the bark, wood, and decoction of Alstonia 

 constricta to the Paris Exhibition. 



England. — The Colouring Matters of Plants. — Though this is 

 hardly the place in which to notice the optical arrangements and 

 working of Mr. Sorby's spectroscope, we may draw attention to 

 some of the results which he has obtained from its use in investi- 

 gating vegetable colours. At a late meeting of the Eoyal Society, 

 he described a new method for registering, by means of an inter- 

 ference spectrum, the position and character of the absorption 

 bands obtained in a spectrum by the interposition of a coloured 

 solution between the spectroscope and source of light. He has also 

 made use of the action of sulphite of soda, citric acid, ammonia, and 

 other reagents for separating or modifying these solutions, and has 

 been able to distinguish above 100 distinct colouring matters. The 

 blue of one flower is not the blue of another, nor are all pinks, 

 greens, and yellows of the same component parts. Two or even 

 more separable colouring matters unite in many cases to give a 

 petal its particular tint and often one of these is peculiar to the 

 plant, The most remarkable fact which Mr. Sorby appears to 

 have elicited is that (in all probability) the absorption bands of any 

 single colouring matter occur at equal distances in the spectrum 

 (allowing for dispersion) and hence that we may infer the presence 

 of more than one colouring matter in a solution which gives absorp- 

 tion bands disposed at unequal intervals. 



Alleged New British Heath. — Dr. Hance writes in the ' Journal 

 of Botany ' for June, that fifteen years since he gathered in South 

 Devon, near Newton Abbot, an Erica, which at the time he con- 

 sidered to be E. mediterranea, the rare species which grows in 

 Ireland. He now, however, considers the species to be E. carnea. 

 This last species is found in Switzerland, Austria, Germany, Italy, 

 Dalmatia, Hungary, and Greece — not in France — whilst E. medi- 



