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Haines . — ^4 New A nxanomete? 
a fibre to the hook which usually carries the load, while the inking pen is 
attached to the thread on which the ‘ work ’ is done. 
2. The inking mechanism, to avoid friction, does not travel on 
a vertical wire as in Ganong’s instrument, but runs horizontally on a mono- 
rail, two-wheeled trolley. 
3. The pen on the trolley travels over a rotating drum which is 
actuated by a large falling weight and made to revolve once in twelve 
hours by a clock mechanism ; and 
4. The particular arrangement of pulleys over which the fibres pass 
forms a complete compensating mechanism for general expansions and 
contractions in the fibres, so that no error is introduced by variations in the 
relative humidity of the surrounding atmosphere. 
3 A 
Fig. 1 is a diagrammatic representation of the instrument, showing 
only the essential features without the compensating gear for changes in 
length of the fibres. A fibre attached to the tip of the plant round a cotton- 
wool pad passes over the two pulleys A and B, and down to the hook which 
carries the pulley C. The pulley C is in the loop of a thread Q R, of which 
the end R passes round one of the grooves of larger radius of the 
differential pulley E, while the end Q passes round a groove of smaller 
radius in the opposite direction. Each end passes about one turn round its 
own groove and is then affixed to the rim of the pulley. Round that groove 
on E which has the largest radius passes a fibre U, one end of which is 
affixed to the pulley, while the other is attached to the trolley F. The 
