806 Remarks on a collection of Plants, [Dec. 



at stated times. This would also enable us to ascertain whether the 

 carbonate existed in the water, or whether it was formed during the 

 evaporation, by the action of the lime or other earths. The presence 

 of magnesia, of potash, and of iodine also remains an undecided 

 point, as well as the nature of the pink or amethystine colouring 

 matter remarked in some of the specimens (A No. 24). 



To conclude this hasty note, I may mention that I have found M. 

 Gay Lussac's alkalimeter a very convenient instrument for examin- 

 ing these mixed salts. By preparing three standard bottles of dilute 

 nitric acid, nitrate of barytes, and nitrate of silver, adapted to his cen- 

 tesimally-divided dropping glass, the per centage of carbonate, sul- 

 phate, and muriate, is obtained successively from the same specimen 

 with great ease and rapidity. 



J. P. 



X. — Remarks on a collection of Plants, made at Sadiyd, Upper Assam, 

 from April to September, 1836. By William Griffith, Assistant 

 Surgeon, Madras Establishment, on duty in Upper Assam. 



The following remarks may not be uninteresting, as they concern 

 a portion of India of which, especially so far as regards its natural 

 productions, but little is known. I must beg, however, to point out 

 that they must be considered as outlines only of a slight sketch ; 

 since the amount of plants collected in Assam does not probably 

 exceed 1 ,500, and this can scarcely be considered more than one- 

 fourth of its whole Flora. 



The greater portion of Assam that I have seen, may be compared 

 to an extensive plain, intersected in various manners by belts of jungle, 

 the breadth of which, although extremely variable, does not, except 

 towards the hills enclosing the valley, seem to be often very great. 

 But as we approach towards the eastern boundary, the spots unoccu- 

 pied by jungle become fewer and less spacious : so that between 

 Kujoo Ghat on the Noa Dehing, and Nungroo on the Booree Dehing, and 

 in the whole of that direction, the country is almost exclusively oc- 

 cupied by jungle. The characters of a plain intersected by narrow 

 belts of jungle is very obvious about Sadiyd, at which place the 

 collection was almost entirely formed. 



The peculiar feature of Assam, especially its lower and central 

 divisions, consists in the vegetation of its churs, or tracts of sand, very 

 often of great extent, which are stretched along the Burhampootur. 

 The breadth of these tracts, taken together, is, in some places, from 8 



