however, causes a somewhat more marked difference between 
the two seasons. In April, the rains become less frequent and 
then, until October, there are no or but very few heavy precipi- 
tations; some times the fallen leaves on the ground in the woods 
are dried out and even the dew is absent. There then occur, 
however, especially in the months of June, July and August, 
steady cold spells, when the thermometer, in the morning, sinks. 
to 8° C. and often does not go above 12° C. during the day. 
These so-called Friazens last several days and are recurrent, but 
cease in September. Thunder storms and violent rain storms 
begin in October, so that in November the rivers are usually 
navigable again. In December the first steamships arrive. In 
January and February a rainless period is frequent, which is 
followed, in March and April again, by a rainy spell. Many 
steamers undertake, usually at this time, their second voyage 
and if they have good fortune they make three trips to upper 
Acre. 
The copious precipitation, the heat and the fertile soil have 
produced in Acre a luxuriant primeval forest, which is higher 
and more densely overgrown than that of the lower river courses 
of the Amazon country. Trees of 40 to 50 meters in height 
are not infrequent, they form a forest of varied composition. 
There may be found here representatives of the most diverse 
plant families; some of which, in the cool season, lose their 
foliage. The forest is densely overgrown with plants, shoots 
and shrubs. Where a thorny growth, Tapoea and other under- 
brush gets the upper hand, a macheté or axe is necessary in 
forcing a path through the virgin forest. 
Various kinds of trees are used by the natives for building 
houses, fashioning canoes and other purposes. For export, how- 
ever, neither these useful woods nor many other products of 
the forest, have attained any importance. The fruit of the cacao 
tree and Para nuts, rot on the ground, transportation to Manaos 
being too costly.. The caoutchouc products are, however, present 
in such abundance and possess such great value, that their ac- 
quisition and transportation recompenses every effort and have 
been the cause of the development in these distant primeval 
forests of a busy life. 
The water in the deeply hollowed bed of the Acre, swells 
in flood time and submerges the land on the adjacent shores 
and some sand banks, but for the most part does not penetrate 
into the forest or only for a short period. The flooded forests of 
the lower water courses, often miles in extent, are lacking and 
the fine rubber trees grown on land free from inundation, often 
reaches up into the hills in the hilly or mountainous district. 
The fine rubber tree belongs to the Hevea brasiliensis, Mull, 
142 
