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V. Experimental Researches in Magnetism and Electricity. By H. Wilde, Esq. 
Communicated by Dr. Faraday. 
Received March 26, — Read April 26, 1866. 
§ 1. On some new and paradoxical Phenomena in Electro-magnetic Induction , and their 
relation to the Principle of the Conservation of Physical Force. 
§ 2. On a new and powerful Generator of Dynamic Electricity. 
1. The principle of the conservation of force, as I apprehend it, is the definite quan- 
titative relation existing between all the phenomena of the universe whatsoever, both 
in direction and amount, whether such phenomena be considered in the relation of 
cause and effect, or as antecedent and consequent events. 
2. In the particular application of this principle to the advancement of physical science, 
and also to the invention of new engines and machinery to meet the progressive require- 
ments of society, problems not unfrequently present themselves which involve the con- 
sideration of static and dynamic force, from several different aspects ; and the solution of 
these problems often brings out results which are as surprising as they are paradoxical. 
Of such cases, in which the idea of paradox alluded to is involved, may be mentioned 
the one contained in the 36th Proposition of Newton’s ‘Principia’ (Book 2, Cor. 2)*, 
and in D. Bernoulli’s ‘ Hydrodynamica,’ p. 279; in which the repulsive force of a jet 
of water issuing from a hole in the bottom or side of a vessel with a velocity which a 
body would acquire in falling freely from the surface, is equal to the weight of a column 
of water of which the base is equal to the section of the contracted vein and about twice 
the height of the column which produces the flowing pressure; the static force of reac- 
tion being thus double that which, without experiment, had been predictedf. An 
instance in which the quantity of dynamic force is increased paradoxically may be seen 
in that curious and useful piece of apparatus the injector, by means of which a boiler 
containing steam of high pressure is able to feed itself with water through a hole in its 
shell, though this hole is open to the atmosphere ; or the steam from a low-pressure 
boiler is enabled to drive the feed-water through a hole (also open to the atmosphere) 
into a high-pressure boiler. Although, when rightly interpreted, these examples of 
paradox, as well as many others of a similar character, are in strict accordance with the 
principle of conservation, yet they are at the same time contrary to the inferences which 
are generally drawn from analogical reasonings, and to some of those maxims of science 
which are framed for the instruction of the unlearned. As the examples cited are only 
* Principia, 2nd Edition. f Ibid. 1st Edition, Rook 2. Prop. 37. 
MDCCCLXVII. N 
