1831 .] 
Philosophy in Sport » 
21 
of people to whom It has hitherto been repulsive or inaccessible, have induced me to 
refer to some notes from the work above named, which has been attributed to, and 
contains internal evidence indicating the facetious author of the Essay on Diet. 
The subjects of these notes will appear trivial to some of your readers ; and, but 
for their author’s celebrity, I would not have ventured to obtrude them on your at- 
tention : they are, in external form, nothing more dignified than peg-tops and trund- 
ling hoops, though capable of yielding much euphonous controversy. Dr. Paris is 
responsible for all that follows between brackets. 
The Hoop. [Its rolling on without any disposition to fall “ is owing to the cen- 
trifugal force, which gives it a motion in the direction of a tangent to the circle, and 
consequently overcomes the force of gravity,” — as in the instance of the glass full 
of water being whirled round the hand without spilling. The difficulty in making it 
go straight forwards is occasioned by the impossibility of giving it each time a straight 
forward blow, added to inequalities in the ground and hoop. Vol. I. p. 231.] The 
ipsissima verba above quoted are pure verbiage. The hoop moves, like any other pro- 
jectile, as long as its impetus continues superior to its gravitation ; the only pecu- 
liarities in its mode of progression being occasioned by its friction on the ground, 
and consequent rolling motion. 
The Top. [Its erect position, when in rotatory motion, is “ owing to the centri- 
fugal force.” “ \ ou have already learned, from the action of the sling, that a body 
cannot move in a circular path without making an effort to fly off in a right line 
from the centre ; so that if a body be affixed to a string, and whirled round by the 
hand, it will stretch it, and in a greater degree according as the circular motion is 
more rapid. The top, then, being in motion, all its parts tend to recede from the 
axis, and with greater force the more rapidly it revolves : hence it follows that these 
parts are like so many powers acting in a direction perpendicular to the axis ; but 
as they are all equal, and as they pass all round with rapidity by the rotation, the 
result must be, that («) the top is in equilibrio on its point of support, or on the ex- 
tremity of the axis on which it turns. 
[“ It is evident that the top, in rising from an oblique to a vertical position, must 
have its centre of gravity raised.” This was not occasioned by the centrifugal force : 
“ it entirely depended upon the form of the extremity of the peg, and not upon any 
simple effect connected with the rotatory or centrifugal force of the top. I will first 
satisfy you, that were the peg to terminate in a fine 
point, the top never could raise itself. Let ABC 
be a top spinning in an oblique position, having the 
end of the peg on which it spins brought to a fine 
point. It will continue to spin in the direction in 
which it reaches the ground, without the least ten- 
dency to rise into a more vertical position ; and it 
is by its rotatory or centrifugal force, that it is kept 
in this original position : for if we conceive the 
top divided into two equal parts, A and B, by the line 
X C, and suppose, that at any moment during its spinning, the connection between 
these two parts were suddenly dissolved, then would the part A fly off with the given 
force in the direction a, and the part B with an equal force in the direction b ; whilst, 
therefore, these two parts remain connected together, during the spinning of the top, 
these two equal and opposite forces A and B will balance each other, and the top 
will continue to spin on its original axis. Having now shewn that the rotatory or 
centrifugal force can never make the top rise from an oblique to a vertical position, 
I shall proceed to explain the true cause of this change j and I trust you will be sa- 
