Prof. Emerson on the Lenticular Stereoscope. 403 
is a remarkable absence of particles larger than a pin’s head. The 
surface of the Parnallee stone under a file shows countless points 
of metallic reflection, the metallic nickel being almost in a 
spongy state resembling silver reduced from its chlorid by zine. 
he mineralogical constituents of this stone are clearly brought 
out on a polished surface, which then presents a porphyritic 
appearance.* ] 
exists in nodules of some size, while in the Parnallee stone there 
h h 
Arr. XLVI.—On an Improvement dn the Lenticular Stereoscope ; 
by Prof. E. Emerson, Troy University. 
So generally known. A common result of one fault is the diffi- 
culty which is experienced in endeavoring to unite the dissimilar 
ble, and the observer, after a series of exercises, exceedingly 
furnished by the dealers in Europe and America. Negatives 
including a much larger angle are readily obtained, but the 
. 
Sacrifice 
* Prof. Casssel’s notice of the Parnallee meteorite has been in our hands for some 
Months, We have taken the liberty to add some details to the mineralogical de- 
‘cription, having by the kindness of Prof, Young of Hudson, O., bad the gee dl 
ge 
of inspecting the stone now in the Cabinet of the Western Reserve College. er- 
a : 
ses—always difficult and unsatisfactory. : 2€ 
received and t liberty longer to withhold Prof. Cassels’ paper, which 
= Mine cae npr saint ith the remarks of Mr. Haidinger, (see 
eteorol 
In a private ] sr. Haidinger says: “As to the structure of the Parnallee 
meteor sate saincod it ith thoes Ha our Imperial Cabinet and find that among 
them all it has the closest resemblance to the meteorite which Piddington of ae 
Prof. Smith’s results have not been 
Is 
discovered among a lot of rocks from Assam in 1846,” (See this vol., p. 143. 
