TiCHBOENE — On the Transition of Compounds. 
189 
important elements that it is not capable of experimental verifi- 
cation. 
If a very strong and boiling solution of chlorate of qninia be al- 
lowed to cool, we find that when the solution arrives at a temperature 
of about 47° C. the salt begins to fall out, but not in a crystalline 
form. On examination with a magnifying lens it will be seen that it 
is separating in globules, which, from the natural laws of fiuids float- 
ing in fluids, take the shape of perfect spheres. These, as they 
separate, arrange themselves, as seen in fig. 2 a, the facsimile of a 
microphotograph taken by Mr. Woodworth for me. There is generally 
one large sphere surrounded by a number of small ones, which fre- 
quently coalesce, showing that they are simply obeying the ordinary 
laws of gravity of mass. The colloid spheres, after some time, become 
crystalline. Thus, starting from the centre, crystals shoot out to the 
periphery, and produce those elegantly arranged masses, so well 
shown in wavellite ; indeed, the salt chlorate of quinia, when viewed 
in the vessel in which it is crystallized, bears such a wonderful resem- 
blance to that mineral that this salt might be aptly termed organic 
wavellite. If we make a section of one of the globes of wavellite, 
we shall generally find that outside of the general mass is a layer of 
crystals, which are evidently a distinct supplementary formation. 
This would seem to be a further formation of the mineral after it had 
ceased to be deposited in the colloid spheres, or perhaps the alteration 
in character of the mineral, from a change in the temperature at which 
the mineral was no longer deposited in its colloidal condition. Two con- 
ditions of deposition are likewise observed in the organic salt. This 
outside layer generally forms but a small proportion to the mass of the 
sphere in the mineral. The conversion of the compounds of the triox- 
ides into the colloidal state, on heating their solutions, is rendered pro- 
bable by their slowness in crystallization, and from the spherical form 
of crystallization so frequently observed in the minerals of this group. 
Many of their salts also exhibit this phenomenon. Thus, if a solution 
of hydrated ferric chloride is crystallized by slow evaporation, distinct 
and well-formed crystals of the salt are produced ; but if it is evapo- 
rated by heat to a strong solution, and to such a point that there is a 
limited amount of available water, it crystallizes by reabsorption of 
atmospheric moisture in the spherical form,* from the radii striking 
out to what must evidently have been the periphery of colloidal sepa- 
rations. 
* Feo Cle, 6 H2O, Mohr. 
