On Subdivision by Trituration and Solution. 53 
same degree of fineness as would be effected by such an opera- 
with 
ordinar process, nor the peculiar advantages of this process in 
avoiding that limit 
of physical inquiry, this subject has especial interest at the pres- 
ht time, when the attention of philosophers is becoming more 
and more directed to molecular forces, and the peculiar properties 
of small masses. The recent experiments of Sir G. C. Haughton 
e afforded id f the identity of molecular magnetism 
and cohesion, and new proofs that all bodies are magnetic when 
they are rendered sufficiently smal].* What intensity of mag- 
hetism may not be expected in bodies as minute as those which 
can be suspended fifty or a hundred miles above the earth’s sur- 
face, in air so rarified as to be incapable of reflecting any sensible 
quantity of solar light! I believe this intensity to be far more 
than sufficient to compensate for the reduction of the quantity of 
Ponderable material, and to be adequate to the production of the 
most brilliant aurora borealis. In this case there is probably a 
crystallization, a change from the fluid or aeriform state to that of 
lute solids, whose magnetism ultimately becomes latent after 
aggregation in larger masses. HOF 
_ U believe it to be a general law of nature, that certain proper- 
_ es possessed by small groups of molecules, are m or ren- 
Mmstances are evidently such as to preclude the application of 
VS 0 <¢ LS SO 
