EXPERIMENTS ON INDIGO. £11 



** for ages; and its own comparatively small streams have 

 ** but modified here and there the grand depost*." 



Having been amply gratified with our visit to this sin- Political view 

 gular place, which to the usual magnificence of the West , of the island of 

 Indian landscape unites the striking peculiarity of the local 

 sceie, we reembarked in our vessel, and stood along the 

 coast on our return. On the way we landed, and visited 

 the plantations of several gentlemen, who received us with 

 hospitality, and made us more fully acquainted with the 

 state of this island: a colony which may with truth be 

 described as fortunate in its situation, fertile in its soil, and 

 rich beyond measure in the productions of nature; pre- 

 senting, in short, by a rare combination, all which can 

 gratify the curiosity of the naturalist, or the cupidity of the 

 planter; restrained in the developement of its astonishing 

 resources, only by the inadequacy of population, the tedious 

 and ill-defined forms of Spanish justice, and the severe, 

 though we hope transient, pressure of the times. 



VII. 



Chemical Experiments on Indigo : by M. CHEVREULf. 



J.7jLR. Vauquelin having requested me to examine the Examination 

 cause of that purple smoke, which arises from indigo exposed of the purple 

 to heat, 1 made some experiments for the purpose, of which ?™? kefri>m 

 the followiug are the results. 



Sect. I. On distilling indigo with a gentle heat, the Action of heat 

 products were : 1, an ammoniacal water : 2, sulphur, unit- on indigo. 

 ed probably with oily hidrogen : 3, a thick oil of a brown 

 colour, containing carbonate and acetate of ammonia : 

 4, prussiate and hidroguretted sulphuret of ammonia: 5,'a 



* Vide Mr. Lochead's Obser. on the Nat. His. of Guiana, Edin. 

 Trans, vol. 4. See Journal, 4to series, vol. II, p. 352. 



t Journ. de Phys. vol. LXV, p. 309. Abridged from the paper 

 read to the Institute, July the 13th, 1907. A fuller account is inserted 

 in the Ann. de Chiiu. vol. LXVI, p. 5, of which the translator has 

 occasionally'aTailed himself. 



purple 



