
MICRO-CRYSTALLIZATION. 25 

MICRO-CRYSTALLIZATION. 
By E. Warp, F.R.M.S. 
RYSTALLIZATION, as a force, was known in primitive times, 
and in a decidely primitive manner. ‘The word crystal, which 
is derived from a Greek word signifying ice or frozen water, 
expressed to the early observers what for a long time was considered 
the great cause of crystallization, for Albertus Magnus about the 
middle of the 13th century tells us that the cold in the lofty 
mountains makes the ice so dry that it congeals into crystals. 
And, although in the 16th century Agricola £zez but little more, 
he rejected extreme cold as the originator of crystals, and accepted 
something similar to Magnetic power. And, as well as indicating 
some simple forms of crystals, he noticed many things which in 
other hands were destined to bear much fruit. 
When Linnzeus, later on, brought his master mind to bear upon 
this, as upon so many other subjects, he evolved from the former 
chaos something like a classification of the forms, still but a very 
imperfect one ; for he affirmed that Sa/¢ was the only known cause 
of crystallization, and that consequently the forms of the crystals 
of all other substances was determined by the Salt in union with 
them. 
‘As well as the cause, the mode of formation of crystals was a 
favourite subject of speculation with the earlier writers on crys- 
tallography, and it still attracts numerous enquirers; but the 
scientific progress has not been as great or rapid’ as many could 
wish. Under our Microscopes, as under those of workers long ago, 
may still be seen crystals springing out of solutions and in- 
creasing in size; but the powers that be are still left much in the 
region of doubt and speculation, and these words of Brewster’s 
still hold true : 
““In whatever way Crystallographers shall succeed in accounting for the 
various secondary forms of crystals, they are only on the threshold of the sub- 
ject,—the real constitution would still be unknown; and though the examina- 
tion of these bodies has been diligently pursued, we can at this moment form 
no adequate idea of the complex and beautiful organization of these apparently 
simple bodies.” 
Not being a student of crystallization as a science I have not to 
discourse on the classification or angles of crystals, but to describe 
in as simple a manner as possible how I have produced and how 
you may probably produce interesting, beautiful, and valuable 
Microscopical slides of some of these wonderful forms. 
I have said advisedly, how you may frobably produce these 
things, for it does not follow that if one worker has produced an 
interesting slide of crystal and accurately describes the process by 
