86 PARTICULAR CONSIDERATIONS ON THE 



formible to that principle, acknowleged to be so generally 

 visible in the affairs of Providence, to have all done by 

 the employment of the smallest possible amount of means 

 Thus, as one set of laws produced all orbs and their mo- 

 tions and geognostic arrangements, so one set of law* 

 overspread them ail with life. The whole productive o? 

 creative arrangements are therefore in perfect unity. 



PARTICULAR CONSIDERATIONS RESPECTING 

 THE ORIGIN OF ANIMATED TRIBES. 



The general likelihood of an organic creation by law 

 having been shown, we are next to inquire if science has 

 any facts tending to bring the assumption more nearly 

 home to nature. Such facts there certainly are ; but it 

 cannot be surprising that they are comparatively few and 

 scattered, when we consider that the inquiry is into one 

 of nature's profoundest mysteries, and one which has 

 hitherto engaged no direct attention in almost any quarter. 



Crystallization is confessedly a phenomenon of inorga- 

 nic matter ; yet the simplest rustic observer is struck by 

 the resemblance which the examples of it left upon a win- 

 dow by frost bear to vegetable forms. In some crystalli- 

 zations the mimicry is beautiful and complete ; for exam- 

 ple, in the well known one called the Arbor Diance. An 

 amalgam of four parts of silver and two of mercury being 

 dissolved in nitric acid and water equal to thirty weights 

 of the metals being added, a small piece of soft amalgam 

 of silver suspended in the solution, quickly gathers to it- 

 self the particles of the silver of the amalgam, which form 

 upon it a crystallization precisely resembling a shrub. 

 The experiment may be varied in a way which serves 

 better to detect the influence of electricity in such opera- 

 tions, as noted below.* Vegetable figures are also pre- 



* " A glass tube is to be bent into a syphon, and placed with ibo 

 curve downwards, and in the bend is to be placed a small portion 

 of mercury, not sufficient to close the connexion between the two 

 legs ; a solution of nitrate of silver is then to be introduced until 

 it rises in both limbs of the tube. The precipitation of the mercury, 

 in the form of an Arbor Dianae, will then take place, slowly, only 

 when the syphon is placed in a plane perpendicular to the magnetic 

 meridian ; but if it be placed in a plane coinciding with the mag- 

 netic meridian, the action is rapid, and the crystallization partiqu- 



