68 On the elementary Particles of certain Crystals. 
black and white throughout. The four black balls are alf 
in view. The distances of their centres being every way 2@ 
superficial diagonal of the cube, they are equidistant, and 
their configuration represents a regular tetrahedron ; and 
the same is the relative situatiow of the four white balls. 
The distances of dissimilar adjacent balls are likewise evi- 
dently equal; so that the conditions of their umion are 
complete, as far as appears in the small group: and this is 
a correct representative of the entire mass, that would be 
composed of equal and similar cubes, . 
Since the crystalline form and clectric qualities of bora- 
cite are perhaps unique, any explanation of properties so 
peculiar can hardly be expected. It may, however, be re- 
marked, that a possible origin of its four pair of poles may 
be traced in the structure here represented ; for it will be 
seen that a white ball and a black one are regularly opvosed 
to each other at the extremities of each axis of the cube. 
An hypothesis of uniform intermixture of particle with 
particle, accords so well with the most recent views of 
binary combination in chemistry, that there can be no ne- 
ecssity, on the present occasion, to enter into any defence 
of that doctrine, as applied to this subject. And thongh 
the existence of ultimate physical atoms absolutely indivis!- 
ble may require demonstration, their existence is by no 
means necessary to any hypothesis here advanced, which 
requires merely mathematical points endued with powers of 
attraction and repulsion equally on all sides, so that their 
extent is virtually spherical, for from the union of such 
particles the same solids will result as from the combination 
of spheres impenetrably hard. 
There remains one observation with regard to the sphericat 
form of elementary particles, whether actual or virtual, that 
must be regarded as favourable to the foregoing hypothesis, 
namely, that many of those substances, which we haye 
most reason to think simple bodies, as among the class of 
metals, exhibit this further evidence of their simple nature, 
that they crystallize in the octohedral form, as they would 
do if their particles were spherical. 
But it must, on the contrary, be acknowledged, that we 
can at present assign no reason why the same appearance of 
simplicity should take place in fluor spar, which is presumed 
to contain at Jeast two elements; and it is evident that any 
attempts to trace a general correspondence between the 
erystallographical and supposed chemical elements of 
bodies must, in the present state of these sciences, be pre- 
mature. 
Nate, 
