1851.] OF THE ROYAL INSTITUTION. 91 
mental operations, there is always a deficiency of facts corresponding 
to the imperfection of theory ;— that is, we only seek and see those 
facts which are more or less connected with our theoretical notions, 
and in most cases shut our eyes to such cases as appear contrary to 
them. This is peculiarly the case with chemical theory and chemical 
facts at the present day; for our atomic theory represents only cer- 
tain simple and definite proportions of combination, and our re- 
searches have been fruitful in the investigation of such cases alone, 
the number of compounds of which we know nothing being infinite, 
compared to those definite ones which we have studied. 
In fact, it is certain that if we could sufficiently disengage our 
minds from preconceived notions on the subject, we should view 
those substances, which, by more or less troublesome processes, we 
separate out from the bodies presented to us by nature, rather as 
exceptional and artificial products, than as the most normal and 
natural. 
The lecturer submitted that the definite compounds hitherto ex- 
clusively acknowledged and studied by chemists, are in truth only 
exceptionally simple cases of combination, and that the consideration 
of chemists is only limited to them, because the atomic theory is as 
yet purely statical. The atomic theory has hitherto been tacitly con- 
nected with an unsafe and unjustifiable hypothesis, namely, that the 
atoms are in a state of rest; the dynamics of chemistry will com- 
mence by the rejection of this supposition, and will study the degree 
and kind of motion which atoms possess, and reduce to this one fact 
the various phenomena of change, which are now attributed to occult 
forces. But although it will probably be generally used in con- 
nection with the atomic theory, the fact of motion is independent of 
any particular theory ; and however the properties of matter may be 
conceived, it will remain true, that a change of place among the 
representatives or possessors of these properties, is constantly going 
on, which produces the phenomena of chemical combination, 
Chemical science has proved the indestructibility of matter, but it 
has yet to prove the indestructibility of motion or momentum by 
showing its transfer and dispersion among atoms. 
There are many primd facie evidences that time is necessary for 
chemical action : — but this fact, although it has been noticed, has not 
as yet entered into the explanation of phenomena. 
_ The one instance in which a certain regular motion of the con- 
stituents of a mixture was first proved, is the process of etherification, 
of which the anomalous character has long since attracted the atten- 
tion and study of many of the most eminent chemists, and has given 
rise to various theories which respectively represented part of the 
phenomena. 
The lecturer referred to the importance of having a correct 
standard of comparison for the various chemical groups or molecules, 
and briefly alluded to the evidence afforded by the formation of the 
intermediate ethers, that alcohol and various bodies allied to ‘it have 
No. 7. H 
