THE MECHANISM OF BICYCLES. 
393 
the majority of riders will call to mind occasions when it has been of 
the greatest convenience, to say the least of it, to back pedal either 
supplemented by the use of the brake or not. It is also inconvenient 
not to be able to wheel the machine backwards. In justice to the 
makers I should tell you that they provide each machine with a 
powerful rim brake, the details of which want of time prevents my 
going into on this occasion. 
The Northfleet gear resembles the Protean insomuch that it has a 
free wheel and also changes of f gear 9 are admissable, but the mode of 
carrying out these two principles differ. The free wheel is worked by 
a friction clutch instead of a ratchet. There is no chain or sprocket 
wheel. The pedal cranks are each connected with arms inclined at about 
sixty degrees and so form two bell crank levers. To the arms on 
which the pedals are not attached, and which we will call the counter¬ 
levers, are attached the ends of wire rope formed of four strands of 
piano wire. On leaving one counterlever the wire passes nearly twice 
round an eccentric pulley on the friction clutch on one side of the 
wheel, thence round a pulley attached to the bottom bracket and back 
again to another eccentric pulley on the other side of the wheel and 
from there to the other counterlever. The pedal cranks do not 
revolve through a larger angle than about 90° and so the feet have a 
reciprocating motion up and down through an arc, and since each 
eccentric clutch only actuates the wheel in one direction, as one pedal 
is pulling on the wire and moving the eccentric clutch the other pedal 
is being pulled up into the position required for the next stroke. Now 
for altering the gear it will be seen that the ends of the wire can be 
attached to the counterlevers at any of five positions. If attached 
close to the fulcrum, greater leverage will be obtained, but at the loss 
of speed since the end of the wire moving over a shorter length of arc 
the driving wheel will be turned less than if the wire were attached 
further away from the fulcrum. The five positions represent gears of 
from 40 to 100. The wires are attached to the counterlevers by 
rollers and pawls which fit into slots in the arms; these pawls can be 
released and the rollers moved from one to any other position by 
pressing a pneumatic button on each handle in turn. 1 
For a long time many endeavours have been made to do away with 
the chain, it being held by a certain number of people that it has great 
disadvantages in requiring adjustment, difficulty of lubricating, keeping 
it clean and the increase of friction when it gets dirty, all disadvan¬ 
tages no doubt ; but public opinion, in the form of the majority of the 
riders met with, still appear to cling to the chain apparently preferring 
to put up with or combat, more or less successfully, with the draw¬ 
backs enumerated than to use any of the chainless machines which 
have been put before them. 
One of perhaps the best known chainless safety bicycles is that call¬ 
ed, presumably from its size, the Bantam. This is a front driver, and 
as far as the mechanism is concerned it is no doubt very neat and com- 
(! The machine was ridden by Captain Crampton on a “ home trainer ” and the action of 
changing the gear exhibited). 
