226 T.S. Hunt on the Theory of Chemical Changes. 
northern parts of Vermont, in the autumn of 1851, a singularly 
beautiful echo was noticed on the borders of a small lake, known 
as Island Pond. The voice, pitched on a high key, was answer- 
ed distinctly thirty-six times, and the discharge of a fowling piece 
was followed by a prolonged roar which lasted for several seconds. 
This experiment was made on an evening following a balmy day 
in October. A dense forest skirted the opposite edge of the lake, 
from whose level a series of lofty hills rose in the form of an am- 
phitheatre. The atmosphere had been hazy during the day; 
but the sky at the time was partially overcast, and the air moist 
and warm; rain followed the next day. 
(To be continued.) 
Art. XXVL—Considerations on the Theory of Chemical 
Changes, and on Equivalent Volumes; by T. 8. Huns, of 
_ the Geological Commission of Canada. 
Iv the proposed inquiry we commence by distinguishing be- 
tween the phenomena which belong to the domain of physics, 
and those which make up. the chemical history of matter. We 
conceive of matter as influenced by two forces, one of which 
produces condensation, attraction, and unity, and the other expal- 
sion, repulsion, and plurality. Weight, as the result of attraction, 
is a universal property of matter. Besides this, we have its vati- 
ous conditions of consistence, shape and volume, with the rela- 
tion of the latter to weight, constituting specific gravity, and wad 
relations of heat, light, electricity and magnetism. A deseriptio® 
of these qualities and relations constitutes the physical history of 
matter, and the group of characters which serve to distinguish 
one species from another, may be designated the apparent or spe 
cific form of a species, as distinguished from its essential Jor ‘fc 
The forces above mentioned modify physically the spec’ 
of such changes, consists the chemical activity of matter yo 
oduction 
which belongs to organic existences. The distinetion 7 
from that individuation which marks the results of ener 
uality not only of the organism, but of its several parts, ie 
evident as we ascend the scale of organic life, while more”. 
bodies have a specific existence, but no individuality ; 
does not destroy them. Solidity or crystallization is 
