THE MECHANISM OF BICYCLES. 
405 
ing a machine careful measurements should be taken and it should be 
made to fit the rider, and, secondly, the bearings, fittings &c. when 
once adjusted should not be pulled about except when absolutely 
necessary. It is a simple matter to know that by screwing up a cone 
or a nut something is tightened, and it is also a very easy thing to over- 
screw that cone or nut so as to permanently injure it. 
I hope that any lady or gentleman who has ridden any of the 
machines exhibited will be kind enough to give us the benefit of their 
experience. 
I will now ask Major Holden to show us his motor bicycle. 
DISCUSSION. 
MAJOR H. C. L. HOLDEN, E.E.S., R.A. then exhibited and explained the 
working of his patent Motor Bicycle. The following is a short description of the 
machine and a general idea of it will be obtained from the engraving. 
The machine has a front wheel of twenty-four inches in diameter and a rear 
wheel twenty inches in diameter, the former being fitted with cranks and pedals 
to enable the bicycle to be started and assisted or actually driven if so required, 
whilst the latter has cranks on each side of it to which are attached the connect¬ 
ing rods of the engine. 
The engine is built into and forms part of the frame of the bicycle proper, in 
such a way that it strengthens the frame and is mutually strengthened by it. 
The engine itself is a four cylinder gas engine consisting of two steel tubes form¬ 
ing the cylinders clamped between castings at either end by steel bolts* 
In each of the tubes there are two pistons rigidly connected together, and the 
four pistons are furthermore connected by a cross-head pin, passing through the 
connecting rods. They thus move to and fro together, and rotate the hind wheel. 
As in any gas engine using the Otto cycle, only one stroke in four is a working 
one ; in this case however, owing to there being four cylinders combined together 
in one engine, every stroke is an effective one. 
The firing of the explosive mixture is effected by an electric spark, the means 
for producing which are contained in a box situated behind the rider. 
The saddle is fitted with a special post which allows of its being shifted six 
inches forward or backward so as to obtain the most comfortable position when 
the feet are on the foot rests which may be seen on either side of the machine. 
The control of the machine is effected entirely from the handle bar. 
On the right side just in front of the grip, is a trigger switch which, allows the 
rider to cut off or turn on the electric current without shifting his hand; on the 
left side is a lever which can be adjusted by its milled screw head without letting 
go of the handle; this lever regulates the proportion of gas and air admitted to 
the engine cylinders thus controlling the power of the engine and, within limits, 
the speed of the machine. 
The weight complete is just over 100 lbs., sufficient benzoline (from which 
the gaseous mixture is made), is carried in the tank to propel the machine some 
seventy-five miles. On level ground a speed of over twenty miles per hour is 
easily attained and gradients of one in fifteen can be ascended without assistance 
from the rider, with his assistance any hill that can be surmounted on an ordinary 
bicycle can be climbed and with greater ease. Going down hill this bicycle is 
always under perfect control as the supply of gas having been cut off, the com- 
37 
