32 Count Bournon on certain Minerals broi/g/it 



was at- the time almost a stranger to them. M. Leschenaulf, 

 remarkable for his extensive knowledge in different branches 

 of natural history, and especially for his zeal and activity, 

 which are equalled only by his great modesty, during a stay 

 of six years in India, scarcely seven months of which were de- 

 voted to the researches which he made in the island of Cey- 

 lon*, has enriched the French colonies, and principally the 

 Jardin Royal of the Isle of Bourbon, with a great number of 

 plants, useful to the agriculture of the island, as well as to the 

 amelioration, in this respect, of its commercial relations. After 

 haying enriched the Jardin du Roi at Paris with many plants; 

 birds, quadrupeds, insects, fishes, and Crustacea, which fur- 

 nish several new species, he has returned to his own country, 

 bringing with him an extremely interesting collection of mi- 

 nerals and rocks, which he collected in the different parts of 

 India through which he travelled. After having first sub- 

 mitted this collection to the choice of the professors of the 

 Jardin du Roi, M. Leschenault presented to the private mi- 

 neralogical collection of the King, the specimens which 

 were subjected to a second choice made by me. Though 

 I had to regret the loss of a great number of minerals, ot 

 which he had no duplicates, this second choice has neverthe- 

 less been very useful to the collection, by the facts which their 

 study has put me in possession of. These facts enable me to 

 add some new details to those which I formerly gave relat- 

 ing to corundum and to spinelle; they likewise enable me to 

 make known some others, which the different mineral sub- 

 stances, brought home by this traveller, have introduced to 

 our notice. 



I shall commence these details with the description of the 

 various gangues of the spinelle of the island of Ceylon, which 

 are among the minerals presented to the private collection of 

 the King by M, Leschenault. 



The first gangue is a carbonate of lime and magnesia, or, 

 more simply, a dolomite. It is colourless, and composed of, 

 distinct parts crossing each other in different directions. It 

 contains, thinly disseminated, some small crystals of phosphate 

 of lime of a deep beryl blue, sometimes placed between the 

 particles of dolomite, but more frequently contained in its sub- 

 stance, and which are only discovered by the fractures made 

 to determine the characters of the mineral. These crystals are 



* M. Leschenault arrived at Ceylon at the end of July 1820, and quitted 

 it in February 1831, after having been obliged to return to Colombo by a 

 dysentery; and in the short time of his residence in the interior, the science 

 of botany, the special object of his mission and researches, was in conse- 

 quence that to which I lis chief attention was directed. 



generally 



