On forcing Fruit- Trees to bear, ‘'c. All 
several different concentric rings. Sucly would be the whole of 
the orbits of the satellites of Jupiter, if each satellite left a per- 
manent light in its path; the partial rings myst be like these 
orbs, differently inclined to the equator of the planet: and then, 
their inclinations, and the positions of their nodes, changing in 
periods of greater or less time, embracing several years, their 
centres must in like manner oscillate round that of Saturn; all 
this would cause the apparent figure of the whole of these rings 
to vary. Their motion of rotation would not change this figure 
sensibly, since it only replaces one luminous part by another si- 
tuated in the same plane. It is very probable that the pheno- 
mena observed by M. Schroter are caused by variations of this 
kind. But if a point, more or less luminous than the others, be 
adherent to the surface of one of the partial rings, this point 
ought to move as rapidiy as the ring, and appear to change its 
position in afew hours. We may suppose with great probability 
that it is a point of this kind that Dr. Hersehel has observed. 
I request observers furnished with good telescopes to notice the 
appearances of the ring of Saturn with this view. The variety 
_of these appearances were a great plague to mathematicians and 
astronomers before Huygens had found out the cause: the ring 
was first seen by Gallileo in the form of two small bodies adhering 
to the globe of Saturn; and Descartes, who unfortunately wished 
to explain all things with his principles of philosophy, attributed, 
in the third part of his work, the stationary state of these pre- 
tended satellites, to Saturn’s presenting always the same side to 
the centre of his vortex. We now know that this state is con- 
trary to the law of universal gravitation; which is a sufficient 
reason for rejecting the explanation given hy Descartes, even 
although we do not know the precise cause of these appearances. 
I do not consider the immobility of the ring as Jess contrary to 
this great law of Nature; and [do not doubt but that future 
observations, made with the view I have just pointed out, will 
confirm the results of the theory, and the observations of Dr. 
Herschel. 
LXIX. Aa easy, simple, and infallible Method to force every 
Fruit-Tree to blossom and to bear Fruit. Translated from 
the German of the Rev. GEorck Cuarves Lewis HEMPEL 
(Secretary to the Pomological Society of Altenburgh in 
Saxony) by Guoncz Henry Nornpen, LL. D.E.L.S.&c.* 
In my early years I saw my father, who was fond of pomology 
and skilled in that science, cutting a ring on several branches of 
* From Transactions of the London Horticultural Society. 
trees, 
