Of the higher regions of the eee Li 299 
with radia: quartz, aes where the seal has been used, is 
found in quantity beneath the surface. Among the quartz in 
this vicet I found a few pieces of feldspar, exhibiting a ten- 
dency to disintegration. This fact may render more plausi- 
ble the supposition that this bed of clay has originated from 
the disintegration of feldspar, the quartz connected sie it in 
the original granitic aggregate, still remaining, an 
ed =~ those causes which have reducer! the Shispat to pie 
C. Dewey. 
Williams College, April 9, 1827. 
ew er 
ART. te eee as to the refracting power of the 
higher regions ‘of the Atmosphere. 
_ TC THE EDITOR. 
THe sight of a very large and bright halo, marked with 
prismatic colours, about the moon, on an evening in the ear- 
part of last month, recalled to my mind the Nitigii2 
contained in the last number of your Journal, with r t 
to these appearances. Since nothing better than hy etaaa 
pe been obtained, perhaps by exhausting possibilities, we 
may aid in eliciting the truth : with this view, I sen d you 
—— 
«Nous avons dit,” says reson page 76, To ome 2, Traité 
Blewentaire de Physique, ** que be aap hydrogéne s’exhale des mi- 
s, des latrines, des cimetiéres, 
a Il est aisé de concevoir J ea —- la matiere des feux follets, 
44 on voit au-dessus de ces endroits 
La oo lui | een a s’elever assez haut dans l’atmos- 
peut s’enflammer Base une étincelle électri- 
Orages, zat qu’il augmente alors la emai du tonnerre. 
Voila sans doute pourquoi le Nelaeee est plus fréquent, 
et plus ‘fort dans certains lieux. Quand ce gas detonne, ainsi, il 
brale; alors sa base oul’hydrogéne se saan avec l‘oxigene 
de Vair, forme de eau qui tombe en pluie. En effet, dans les 
gesilya si . —— violentes et subites, apres quel- 
ques coups de tonner 
