also unite with three quantities of oxalic acid; but it was found, that
when two parts of potash are in solution with six equivalent quanti-
ties of oxalic acid, they do not crystallize together in this proportion;
but one part of the potash becomes a true binoxalate by union with
two parts out of the six of oxalic acid taken; and the other part of
potash is found united with the remaining four parts of acid.
The author expresses an opinion that we shall not be able to ex— plain satisfactorily, why this acid refuses to unite in the proportion of 3 to 1, till we can attain a just conception of the geometrical ar- rangement of the elementary particles in all the three dimensions of solid extension. It being supposed, for instance, that the particles are spherical (which is the simplest hypothesis), if they unite l to 1, there is but one mode of union. If 2 particles are united to 1, the 2 particles will arrange themselves at opposite poles of that to which they are united. If there be 3 particles, the only regular position in which they could remain is in the form of a triangle in a great circle surrounding the single spherule; but for want of similar mat- ter at the poles of this circle, the equilibrium would not be stable. But again, if there be 4 to l, a stable equilibrium would occur, when they assume the form of a regular tetrahedron, surrounding the single particle.
But as the author dam not place much reliance on this explanation, since such a geometrical arrangement of the primary elements is altogether conj ectural, he is desirous that it should not be confounded with the results of the facts above related, which are distinct and satisfactory with respect to the existence of the law of simple mul- tiples.
Mr. Knight having on a former occasion observed the bark of trees to originate from a fluid exuding from both bark and albumum, con- tinues the subject by observations, tending to prove that hark thus formed always remains in the state of bark, and that no part of it is ever converted into alburnum, as various eminent naturalists have maintained.
Equal portions of bark from several branches of an apple and a crab-tree were removed by circular incisions, and transposed from tree to tree in the spring; and a vital union was seemed by bandages, and by a plaster of bees’ wax and turpentine.
When some pieces of bark were removed in the autumn of the same year, a layer of albumum was found to have been formed beneath them in every instance; that of the crab-tree having the colour and roughness of the stock on which it was produced, while that of the apple-tree showed none of the sinuosities of the bark of the crabtree which covered it ; neither did the vessels and fibres of the newly-generated alburnum in any degree correspond with those of the trans-
