of a mass of native iron in Brasil. 279 
Many small fish were swimming in the basin of the last, 
from which runs, at all seasons, a considerable rivulet. 
A third was at 90° when the atmosphere was at 73 0 . The 
water very pure. 
A fourth was at 101° when the atmosphere was at 85^-°; 
also at 10 1° when the atmosphere was at 93 0 . 
Taste of the water rather ferruginous, and very brackish, 
extremely disagreeable and nauseous. No peculiar smell, 
and very transparent, although it deposits iron and lime, and 
an iridescent film is formed on its surface. Contains no sul- 
phuretted gas. The rocks of the neighbourhood contain 
pyrites not magnetic. 
This spring is called the Mai-d'agoa, and is situated on the 
left bank of the river Itapicuru, near the water s edge, at a 
short distance from a place called the Mato-do-cipo. 
It was during this journey that I had an opportunity of see- 
ing that curious plant called cipo de cunanam. It grows 
abundantly between Monte Santo and the river Bendego. It 
is a climbing plant destitute of leaves ; it was so when I saw it, 
and I believe it to be always the same ; it bears no thorns ; 
but often growing so as to form an impenetrable plica which 
the cattle will hardly approach, much less attempt to break 
through, because when the juice of this plant sticks to their 
hair, it occasions blisters and great irritation. It contains a 
milky juice, and I suppose that it is an euphorbium. When 
I made a cut at the bush with my hanger, in the dusk of the 
evening, the wounds inflicted presented a beautifully lumi- 
nous line, which was not transient, but lasted for several se- 
conds, or a quarter of a minute. Having taken a piece of the 
plant, I bent it in the dark until the skin cracked, when every 
