Miscellanies. 389 
From the foregoing, it is obvious, that the Milo mineral is not a 
true alum, as was formerly supposed, but a sulphate of alumine; and 
whether it, be identical with the South American alum, described by 
Dr. Thomson, there remains nothing but an apparent coincidence of 
external properties to prove. 
16. Datholite and Iolite in Connecticut.—My attention was called 
a few weeks ago, by Mr. J. D. Dana, of the Junior Class in Yale Col- 
lege, to a small geode of beautifully transparent: crystals imbedded 
in trap, collected by him ata spot, near the village of Middlefield, 
called Middletown falls. He was conducted thither by some of his 
acquaintance in Middletown, to whom the locality was known, and by 
whom the mineral was regarded as Quartz, or Chabasie. Mr. Dana 
however, was satisfied as well from its form as its hardness, that it 
could not belong to the former of these species, and was. doubtful 
of its identity with the latter. 
By an experiment, I immediately satisfied myself that its hardness 
was between 5. and 5.5; and therefore too high for Chabasie. Its 
crystals also, though small and highly complicated, were seen ob- 
viously to belong to a prismatic system of crystallization. A few 
of the angles were ascertained by means of the reflective goniome- 
ter, and a perfect coincidence with the angles of Humboldtite of Le- 
vy, (now known to be Datholite) was detected. The mineral appear- 
ed to me so interesting, no less on account of the modifications of 
its crystals than for the reason that we have long since.ceased to obtain 
specimens of Datholite from Patterson, New Jersey, that I was im- 
mediately induced to visit the spot. 
The falls themselves would have compensated for the visit, con- 
stituting as they do, a beautiful object of picturesque scenery. The 
stream where it precipitates itself over the trap, is apparently two 
rods wide; and when not unusually swollen, two or three feet in © 
depth. I was informed that the height of the fall is thirty feet. 
When viewed from below, it presents a flat surface of unbroken 
foam from top to bottom;—the face of the rock over which the 
stream passes being rough and not perpendicular, but rather making 
an angle of twenty or twenty five degrees witha line vertical to the 
plane of the horizon. ‘The trap upon either side of the river, mounts 
somewhat higher, especially upon the eastern side, where it offers to 
the spectator who is at the foot of the falls upon the opposite bank, an 
overhanging aspect. A profusion of trees and shrubs, moreover, 
Vol. XXII.—No. 2. 50 
