(148 Atmospheric Origin e the Aurora, §c. 
As they are all preceded by a depression of atmospheric tem- 
peraturé’ b w the mean, and by an augmentation of pressure 
greater than that which ninasion the fall of snow or rain at times 
when none of these meteors have recently appeared, there is ne 
. ditional evidence of the similarity of their origin. 
— 7th. | Theoretical inference in relation Ses 0 their alli- 
me may infer from ihe last two propositions that a emis : 
cirrous cloud is higher than a halo, but lower than a junar ee 
and the latter lower than the aurora borealis. 
Proposition 8th. Practical inference with regard to the prog: 
nostication of storms. 
The foregoing propositions which relate to pressure and tempe-. 
rature may suggest a rule for predicting storms much earlier than 
by-other methods; inasmuch as these changes, and especially 
that of the barornster, take place even more generally than those 
opposite changes which often occur within the twenty four hours 
immediately preceding the storm, and which have been observ 
by others, and generally regarded as among the surest indications.’ 
The above propositions are deduced from tables here omitted, 
and are founded upon the. observation of forty auroras, twenty 
two auroral clouds, seen in the day time, seventeen halos, and 
four luminous columns. The propositions in relation to the last 
and more rare phenomenon, the author considered as entitled, ed 
bserved. t 
toa mater oF fidrizontal, specularly-reflecting, crystalline oink 
with masses which are more amorphous and which produce @ 
' reflection virtually radiant, he considers as complete and satisfac- 
tory, and corroborated by his observations on the crystals which 
subsequently descended. T’he author has observed the aurora if 
connexion with the above and other meteorological phenomena 
of the same, the preceding and the succeeding days, and endeav- 
ored to trace their respective and relative changes, and as far as 
the subject admitted, by the statistical and numerical method. 
This is a fertile field, and comparatively unoccupied. 
In the 3d, or class of inferences, he has endeavored to show 4 
connexion between the aurora borealis and the et of 
snow. 
