i88 
Haines . — ^4 New Auxanometer . 
12. Set the drum in motion. 
At this point the whole system is in equilibrium, for in the cases of A 
and B the moments are equal in the two directions and the tension in z has 
been arranged to counterbalance exactly the tension in U. When the plant 
grows the tension in the fibre Y is released so that the moments of the 
forces tending to turn A to the right become greater than those tending to 
turn it to the left. A therefore turns to the right and increases the tension 
in X 2 . This increases the tension in X x and turns the pulley B to the right, 
allowing C to fall. The tension in Q R falls so that E revolves to the right 
as a result of the tension in U. The length of U is therefore increased so 
that the trolley F moves over the drum. When the trolley reaches the end 
of its travel it automatically stops the clockwork so that further rotation 
causes no unnecessary lines on the graph, and the record may be removed 
at the operator’s convenience. 
In conclusion, the author wishes to tender his heartiest thanks to 
Dr. Fritsch and Dr. Salisbury, who have given him every help and facility 
for the prosecution of this work. 
