FINAL CAUSES. 7 



Equally definite are the operations of the forces 

 of cohesion, of elasticity, or of whatever other me- 

 chanical powers of attraction or repulsion there 

 may be, which actuate, at insensible distances, the 

 particles of matter. We see liquids, in obedience 

 to these forces, collecting in spheroidal masses, or 

 assuming, at their contact with solids, certain cur- 

 vilinear forms, which are susceptible of precise 

 mathematical determination. In different circum- 

 stances, again, we behold these particles suddenly 

 changing their places, mashalling themselves in 

 symmetric order, and constructing by their union 

 solid crystals of determinate figure, having all their 

 angles and facets shaped with mathematical ex- 

 actness. 



The forces by which dissimilar particles are 

 united into a chemical compound have been termed 

 Chemical Affinities; and the operation of these 

 peculiar forces is as definite and determinable as 

 the former. They are now known to be regulated 

 by the Law of definite proportions ; a law, the dis- 

 covery of which has conferred on Chemistry the 

 same character of precision which appertains to the 

 exact sciences, and which it had never before 

 attained. The phenomena of Light, of Heat, of 

 Electricity, and of Magnetism have been, in like 

 manner, reduced to laws of sufficient simplicity to 

 admit of the application of mathematical reasoning, 

 and to furnish the accurate results derived from 

 such application. 



Thus to whatever department of physical science 

 our researches have extended, we every where meet 

 with the same regularity in the phenomena, the 

 same simplicity in the laws, and the same unifor- 



