DAVIES, ON CRYSTALLIZATION AND THE MICROSCOPE. 209 
good specimen. When thaw came no failures of the same 
kind teased me, and the crystals were as flower-like as they 
had been before. 
But some have found that, in spite of every care as to the 
covering the edges of the salt with balsam and mounting 
immediately, an “‘ under-growth ” of smaller forms has arisen 
and spread over the whole field, thus robbing the large crys- 
tals of that unity which is part of their charms. I have never 
found this to be the case where the balsam used for mounting 
has been pure ; but when either ¢urpentine or other solvent has 
been added to dilute it this second crystallization is aroused 
either immediately or requires months, according to the 
quality of Solvent added. If the ordinary chloroform-balsam 
is applied the slide is one mass of crystals in a few minutes ; 
but when a small quantity of turpentine has been added to 
the balsam it requires weeks to produce a like effect, and 
progresses very gradually ; -yet the result will as certainly be 
the same. In these cases I have made many experiments, 
and arrived at the conclusion that it was always my old 
enemy, water, that was teasing me; and when we remember 
that turpentine has water in it, and that ether will not dis- 
solve water and yet always contains four or five per cent. 
mixed mechanically with it, no improbability is involved in 
this, as it seems to me, almost inevitable conclusion. Added 
to these facts, the very minute quantity of water required 
Photograph No. 1. 
