4 Configurations and Cryfiah 
fame my Experiments go a great deal far¬ 
ther, both as to the Manner of Examina¬ 
tion, and the Variety of Subjects examined : 
for by the Aid dance of Heat, which in a 
greater or lefs Degree is perhaps a condant 
Agent in ail the Operations of Nature, 
very different Configurations and Effects are 
produced than what can be caufed without 
it, and our Information is thereby rendered 
much more com pleat and perfedt. 
To give one fmgle Indance of this, which 
takes place equally in mod other Subjects : 
The Crydals of Alum are well known, and 
their Figures (when a Solution of it is per¬ 
mitted to crydalize quietly and of itfelf) 
have been truely defcribed and pictured by 
*' ^ X / 
others to be odlaedra, confiding of hexangu- 
lar, triangular, and quadrangular Planes : 
but nobody I believe has before difcover’d, 
s*t leaf! nobody hitherto has informed the 
World, that the Particles of Alum, when 
feparated by Diffolution, and excited to 
Adtion by a certain Degree of Heat, fo 
arrange thenifelves as to compofe regular 
and delightful Star-like Figures of different 
Sizes, many whereof have long dreaming 
Tails, and referable Comets : that it ihoots 
forth in fome Places Figures like Palifadoes, 
and in others an aimed infinite Number 
of parallel Lines, mod exquifitely drait, 
exad and fine ; fome eroding others at 
right Angies, and competing an Appearance 
i beyond 
