MECHANICAL' PROCESSES. CHA!. I. 



the process extremely difficult, requiring much time 

 and labour, and much previous practice in analyti- 

 cal research. But whatever may be the object of 

 analysis, or particular view of the experimenter, 

 the processes which he employs are either mecha- 

 nical or chemical. 



CHAPTER I. 



MECHANICAL PROCESSES. 



KaturaL THE Mechanical Processes are such as are effected 

 by the agency of mechanical powers, and are often 

 indeed the operation of natural causes. For it 

 sometimes happens that of the ingredients contained 

 in a plant, part becomes insulated, extricating itself 

 from the organ in which it was formed and ela- 

 borated, and detaching itself of its own accord. 

 This may be exemplified in the case of such fluids, 

 existing in excess, as do occasionally burst asunder 

 the vessels containing them, and force their way to 

 the exterior of the plant, where, being now ex- 

 posed to the influence and action of the air, they 

 are gradually condensed into a solid mass. And 

 hence the origin of gums and other spontaneous 

 exudations. 



But the substances thus obtained do not always 

 flow sufficiently fast to satisfy the wants or necessi- 

 ties of man. And men have consequently con- 



