A ptj i r. 18.] 
THE COTTAGE GARDENER. 
FRICTION. 
Addressed especially to those who neglect In tjrense their 
axles. 
FmcTrox, the great drawback on all mechanical power, is 
the resistance caused by two surfaces rubbing against each 
other; and the rougher the surface the greater it will be. For 
instance: suppose two files to be put face to face, it would 
require great force to slip them along one another; but if they 
were both polished surfaces like glass, they would pass easily. 
There is, also,another quality besides roughness, which is the 
attraction of cohesion, even where the surfaces are apparently 
smooth. 
Two pieces of smooth iron in passing over one another 
exhibit more friction than if one was of iron and one of brass, 
or any other metal; and this is accounted for in the following 
manner. However smooth a surface apparently is, there is a 
sort of inherent grain in it, which fits into the grain of a 
similar substance, more closely than it would into a sub¬ 
stance of a different texture; and for this reason, the moving 
parts of steam engines, and other machines, are generally 
made of two metals, that is, if the spindle of a wheel is of 
iron, the socket in which it works is of brass. 
To determine the quantity of friction in two substances, 
the following method can be employed : one of the surfaces 
is laid down as an inclined plane, and the other is then 
placed upon it; the plane is now elevated till the upper mass 
begins to slide ; the inclination of the plane, just before the 
sliding commences, is called the angle of repose, and of 
course the less this angle is, or the flatter the plane, the less 
will be the friction on these substances. It is this angle 
which determines the degree of sloping in the sides of hills 
composed of sand, gravel, or earth ; as also in the sides of 
canals, embankments for railways, or the banks of rivers. 
If it were not for friction, we should walk on the ground or 
pavement as if on ice; and oiu - rivers, that now flow so 
calmly, would all be frightful torrents. Friction is useful 
also, when out of the comparatively short fibres of cotton, 
flax, or hemp, it enables us to form lengthened webs and 
cordage ; for it is friction alone, consequent upon the inter¬ 
weaving of the threads, which keeps them together. 
There are several methods employed to diminish friction, 
such as making the nibbing surfaces of different materials. 
In watches for instance, the steel axles are made to play in 
diamond or agate holes ; the swiftness of a skaiter de¬ 
pends much on the great dissimilarity there is between ice 
and steel; again, by interposing some lubricating substance 
between the rubbing parts, as oil for the metals, grease, 
black-lead, <fce., for wood. There is a laughable illustration of 
this in the holiday sport of soaping a lively pig’s tail, and 
then offering him as the prize of the clever fellow who can 
catch and hold him fast by his slippery appendage; the 
countryman, however, without having studied the theory of 
friction, shews a deep practical acquaintance with its laws, by 
rubbing the palm of his band with sand. 
Of all rubbing parts, the joints of animals—considering the 
strength, frequency, and rapidity of their movements—are 
those which have the least friction. We may study and 
admire the perfection found in them without being able very 
closely to imitate it. 
Wheels are perhaps the most successful machines in com¬ 
batting friction, by diminishing tlie distance rubbed over; for 
example—if a sledge were drawn along a road a mile long, 
there would be a mile of rubbing surface; but if the sledge 
were placed on wheels, observe the difference : the rubbing 
surface instead of being on the road, at the extremity of the 
wheel, is in the centre, at the axle; now as the axle is 
perhaps only three inches in circumference, and the wheel 
fifteen feet, each revolution of the wheel, although it will 
have taken the carriage fifteen feet along the road, has only 
caused a rubbing surface of three inches, or one revolution 
of the axle; and as the wheel turns about 350 times in a mile, 
the rubbing surface would amount to only about ninety feet, 
I instead of one mile—so that in drawing the sledge along the 
road, even supposing the road to be perfectly smooth, the 
resistance from friction would have been as much in ninety 
feet as from the wheel-carriage in one mile. 
The broad old-fashioned conical wheel, with the lower 
spokes made perpendicular, and the upper part of the wheel 
banging over, greatly augmented friction; for this wheel formed 
the frustrum of a cone. The circumference of the outside 
30 
part of it would measure much less than the circumference j 
of the side next the cart—the one being perhaps fifteen feet, 
the other sixteen ; therefore as a turn of the large part of the 
wheel would carry the cart forward sixteen feet, and as the 
smaller portion is obliged to keep pace with it, the outer 
edge has actually been obliged to slide one foot along the 
rough surface of the road to keep up with the inner edge. 
"Wheels of this description are not now much in use, though 
they are still occasionally to be seen. 
Resides the saving in friction, the wheel-carriage has 
another advantage over the sledge, in overcoming any abrupt 
obstacle on the road, by the axle describing a gently rising- 
slope or curve; the wheel, as it were, rising on an inclined 
plane, which gives to the drawing animal the relief which 
such a plane would bring. This kind of advantage is pro¬ 
portioned to the magnitude of the wheel, for the smaller 
wheel in order to surmount the same obstacle, has to rise 
in a steeper curve; a small wheel will sink to the bottom 
of a hole, where a large one would rest on the edges. The 
fore wheels of carriages are usually made small, because i 
such construction facilitates the turning of the carriage, 
and not because, according to the popular prejudice, the 
large hind wheels of carriages and waggons help to push 
on the little wheels before them ; but there is this slight 
incidental advantage, that in ascending a bill, when the 
horses have to put forth their strength, the load rests chiefly 
on the large wheels; and in descending, when increased 
resistance is desirable, the load falls chiefly on the small 
ones. In descending hilly roads, it is usual to take ad¬ 
vantage of the resistance caused by friction, to prevent the 
carriage descending too rapidly ; this is generally effected by 
putting the wheel of the carriage into a shoe, thus stopping 
its revolution, and causing it to rub over the surface of the 
road. 
In France, the heavy lumbering diligence is provided with 
a piece of wood running across the carriage, just behind the 
wheels ; this piece of wood is attached to the axle-tree by a I 
strong screw through the middle of it; and iu descending a ! 
hill the conducteiir goes behind and turns the screw till lie 1 
draws the wood close to the outside of the wheels, and by j 
this means he can either entirely stop them, or allow them to I 
grind slowly down the bill, which is the general plan, and a 
most delightful one it is, especially if the outside of the wheel 
is rough, or lias lost a piece of its tire, which is by no means 
uncommon iu French carriages. A machine on the same 
principle, but of very superior construction, is employed for 
stopping railway carriages, and is called a break. 
C. F. Gower. 
HISTORY OF AN APIARY. 
(No. 3.) 
(Continued from page 325.) 
I concluded my former letter with stating my resolution 
to give Air. Nutt's system of bee management a trial. As 
soon, therefore, as the boxes, which had been placed at my 
disposal, were ready for the reception of their proposed 
tenants (after a good cleansing and smearing with honey), 
an early evening was fixed upon for the ejection of my un¬ 
happy bees ( unhappy , as the sequel will shew) from their old 
domicile. I could have wished for a more suitable evening 
than that fixed upon; for the moon was high and bright in 
the heavens, when at about 8 o’clock we sallied forth, a large 
party of ladies and gentlemen, to witness or assist at the ope¬ 
ration ; but tlie season was so far advanced (it was already 
the 2? th of August) that any further delay would necessarily 
have been fatal to the experiment. As it was, it was full late ; 
but I hoped that the vicinity of heath-covered bills might, 
yet, with the assistance *>f copious feeding, enable my bees j 
to more than retrieve their losses. The gardener was the 
chief operator, assisted bv myself and others ; and the plan 
which I proposed to adopt for the transfer of the bees from 
the hive to the boxes, was the old-fashioned one of driving. 
Mr. Nutt, I was aware, strongly reprobates this system; but 
I had no puff-balls at band; and on the whole it seemed to 
me the simpler operation, and I still adhere to it with the 
same persuasion. 
As soon as everything was ready, I commenced the busi¬ 
ness by turning the hive, bottom upwards, and placing it in a 
pail to steady it, while the centre box, or “pavilion of 
