BOTANICAL INFORMATION. 191 



cursions on the Amazon and Rio Negro (j). 34 of our present volunie)^ 

 he speaks, as among the most interesting articles he has sent home for 

 our Museum, of a q^uantity of salt (weighing thirty pounds when put 

 up) made from various species of Podostemacece growing on the cata- 

 racts of the Uaupcs ; it was obtained with considerable difficulty, at 

 several times, and of several different Indians. Mr, Hanbury has 

 been so oblip-inor as to refer us to the eleventh volume of the 'Pharma- 



0'"C3 



ceutical Journar for an analysis of a saline ash, from British Guiana, 

 which undoubtedly has the same origin, although the particular plants 

 which yield that ash were not known till we received the present com- 

 munication from Mr. Spruce. 

 The analysis in question is by Mr. Graves, who gives the following 



account, l. c, ; 



" Among the interesting specimens exhibited at the late Great Exhi- 

 bition, from British Guiana, and presented to the Pharmaceutical So- 

 ciety, was one labelled ' Saline Ash,' which is said to be used by the 

 Indians as a substitute for salt. This ash, in the state we have it, is 

 in black pulverulent masses. It is said to have been obtained by burn- 

 ing certain plants growing on the rocks near the rapids, about a thou- 

 sand miles up the river Demerary. 



" The salt is very easily obtained from the ash, by treating it with 

 cold water, and evaporating the solution to dryness. Seventy-five per 

 cent, of soluble saline matter may thus be extracted, the insoluble resi- 

 due consisting of carbon, siliceous matter, carbonate of lime, and inso- 

 luble phosphates, in the following proportions : 



Carbonaceous matter 

 Siliceous matter 



31- 



44-2 



Carbonate of lime and insoluble phosphates . . 24*8 



cc 



found 



alkalin 



and a small quantity of sulphate. It was tested for iodine, but there 

 w^as none found. 100 grains of the dry salt gave 



Sulphuric acid . 

 Carbonic acid . 

 Chlorine . 



I'D grs. 

 4-4 

 45-648 



'' Now assuming the sulphuric and carbonic acids to be in combina- 

 tion with potash, we should have 84 grains of the cUorides of potas- 



