120 THE AMAZON AN1> MADEIRA RIVERS. 
po.ssible, evai)orate. A good workman is thus able to j)roparc 5 or 
0 lbs. of solid seringa in an hour. The planchu, from its initial coloiir 
of a clear silver-grey, turns shortly into a yellow, and tinally becomes 
the well-known dark bromi of the rubber, such as it is exported. 
TIic more uniform, the denser and freer of bubbles the -whole mas.s 
is found to be, the better is its quality and the higher the price it 
fetches. Almost double the value is obtained for the first-rate article 
over that of the most inferior quality, the so-called seruamby or cube^a 
de negro (negro’s head); which is nothing but the drops collected at 
the foot of the trees, Avith the remains of the milk scraped out of 
the bottoms of the calabashes. The rubber of India is. said to be 
much like this sernamby, and, like it, to be mixed Avith sand and small 
pieces of bark. By Avay of testing the quality, every plancha is cut 
through again at Para; by AA^hich means discovery is made, not only 
of the bubbles, but also of any adulteration that might bo effected with 
the milk of the mangaba, that fine plant Avith dark glossy leaves, noAv 
found so often in European saloons under the erroneous name of 
rubber-plant. 
Of the milk of the mangaba also a sort of spurious caoutchouc is 
made, that has, hoAvover, so little of the elasticity and toughness of 
the genuine article that it has as yet acquii’od no A'alue in commerce. 
But, for certain purposes, for making hardened caoutchouc for instance, 
the mangaba sap Avould certainly serve quite as Avell; imd, as it can 
be obtained at a much loAver price than the true seringa, it would bo 
Avell Avorth the while of European or North Americau firms to send 
agents to the Amazon, to establish depots for the manufactm-e of the 
mangaba resin on the spot, more especially as no such enterprise is to 
bo expected from the selfish anxiety of the merchants at Para. It Avould 
amply remimerate commercial houses in this AAmy of business to haA’c 
local stores and representatives at the chief stations on the Amazon, as 
Manaos, Santarem, &c., more especially as the naAigatiou of the riA'cr is 
noAV opened to the ships of all nations, anu as schooners and brigs can 
easily be towed up by steam-tugs. Hitherto most of the goods have 
been transported by expeditious steamers at very high rates; the 
conveyance of an an-oba of caoutchouc (32 lbs.) from Manaos to Para, 
for example, costing 500 reis (about 1 shilling), whereas by tugs and 
barques it could be easily effected for 300 reis, the passage taking 
sixteen da 3 ^s instead of seven. MorcoA'er, this direct communication 
