ideas of his positions.  Some will doubtless inquire more minutely into the cause and means by which these various actions are produced, what muscles are employed, what supports are rendered by the bones; and the whole regulated by the will of the horse, and their conclusions may be quite opposite.  But this has nothing to do with the obvious fact expressed by the words above; or, more properly, it is not necessary to enter into a minute detail of these minor considerations, these secret springs of motion, in order to relate the actions of the horse.  For were we to do this we should be required to go back, step by step, and find the causes still more numerous, latent, and perplexing.  The pursuit of causes would lead us beyond the mere organization of the horse, his muscular energy, and voluntary action; for gravitation has no small service to perform in the accomplishment of these results; as well as other principles.  Let gravitation be removed, and how could the horse lay down?  He could roll over as well in the air as upon the ground.  But the particular notice of these things is unnecessary in the construction of language to express the actions of the horse; for he stands as the obvious agent of the whole, and the effects are seen to follow—­the horse is laid down, his body is rolled over, the fore part of it is reared up, himself is shaken, and the whole feat is produced by the direction of his master.

Allow me to recal an idea we considered in a former lecture.  I said no action as such could be known distinct from the thing which acts; that action as such is not perceptible, and that all things act, according to the ability they possess.  To illustrate this idea:  Take a magnet and lower it down over a piece of iron, till it attracts it to itself and holds it suspended there.  If you are not in possession of a magnet you can make one at your pleasure, by the following process.  Lay your knife blade on a flat iron, or any hard, smooth surface; let another take the old tongs or other iron which have stood erect for a considerable length of time, and draw it upon the blade for a minute or more.  A magnetic power will be conveyed from the tongs to the blade sufficient to take up a common needle.  The tongs themselves may be manufactured into a most perfect magnet.  Now as the knife holds the needle suspended beneath it you perceive there must be an action, a power, and cause exerted beyond our comprehension.  Let the magnetic power be extracted from the blade, and the needle will drop to the floor.  A common unmagnetized blade will not raise and hold a needle as this does.  How those tongs come in possession of such astonishing power; by what process it is there retained; the power and means of transmission of a part of it to the knife blade, and the reason of the phenomena you now behold—­an inanimate blade drawing to itself and there holding this needle