6*4 Dr. de Crell on the Decomposition 
the fluid obtained by Exp. xvn. having first warmed it a little; 
when, almost in the same instant, a very agreeable phasnome- 
non took place. Crystals, perfectly white, shot forth suddenly, 
and all at once, from every part of the black mass covering 
the sides of the retort. The distillation being continued, these 
crystals were at length dissolved, and entirely removed. The 
supernatant fluid was, as usual, almost colourless. When the 
mass of salt appeared dry, the fire was increased, as in Exp . 
xvm. and the same appearances as above related took place: 
first, the sublimate appeared white, then black, frothy, and 
flowing down the sides. 
Exp. xx. I proceeded, as in Exp. xix. to pour back the 
distilled fluid. Instantly a number of the whitest crystals shot 
forth from the black ground, forming small groups ; but the 
retort was cracked. 
Exp. xxi. I therefore took all the vessels asunder, and shook 
the retort well, till whatever hung upon its sides was dissolved; 
then distilled the fluid in another retort, till the mass of salt 
appeared quite dry. I now put the retort into a crucible, sur- 
rounded it with sand, fitted another receiver to it, and placed 
the crucible in an open fire. First, some sublimate was pro- 
duced, towards the neck of the retort, (but which vanished as 
the heat increased,) and then a small portion of fluid, (hardly 
more than a dram, or a dram and a half,) which appeared to 
stnell a little of the sebacic acid. At the bottom of the retort 
was a blackish mass, a , and likewise some sublimate, b, which, 
by its varied appearance, seemed to be of a two-fold nature. 
Exp. xxii. The residuum taken out of the broken retort 
had a spongy appearance, and swam upon water; it had a 
blackish colour, and weighed three drams and ten grains. 
