128 THE BOOK OF FORESTRY 
across the stream, leaping from log to log which may 
partially sink under their weight. Their skill in 
balancing upon these floating logs is marvelous, and 
to see two expert river drivers ‘‘birling’’ is a sight 
never to be forgotten. } 
In swift water the logs travel rapidly and unless 
there are bowlders or other obstructions in the river 
the chief duty is to pry the logs from the shore and 
push them out into the swift running water in the 
center of the stream. When, however, an obstruction 
is met, trouble is in store for the entire driving crew. 
One heavy log may catch upon a rock or sandbar, a 
few more immediately behind it pile into it and a 
“jam” is formed—a pile of logs pointing in every 
direction like jackstraws. The size of this jam in- 
creases every minute as the swollen stream brings down 
logs continuously. Soon the pile actually fills the 
stream and in some cases the water may be backed 
up by the obstructing logs. Now is the time to rush 
out on the pile and pull away furiously at the front 
of the jam, log by log, working like beavers, with cant- 
hook and pike-pole, until the unruly member, the “key 
log” is found When this is removed the jam starts 
slowly at first but rapidly increases in speed, while 
the expert drivers who have broken the jam rush madly 
to safety, peavy in hand, jumping from one bobbing 
log to another amid the encouraging shouts of the less 
experienced rivermen who have been watching them 
from the shore. In extreme cases it may be necessary 
to start the jam by means of dynamite. 
1 Birling—rotating a floating log by treading it. When two 
experts indulge in a birling match the best balancer wins; a sud- 
den stop of the spinning log throws the unwary or slow moving 
driver into the river. 
