358 Steam Navigation to the Pacific, §e. 
As the analysis quoted gives phosphate of alumina; I applied 
the customary test for phosphoric acid, (of fusion with carbonate 
of soda, neutralization by acetic acid and the addition of nitrate 
of silver,) without being able to detect any traces of this acid. I 
conclude, therefore, that some error has been committed in stating 
the results of Mr. Wurtney’s analysis. If we set down the phos- 
phate of alumina as alumina, the constitution of the mineral 
would not be inconsistent with that of the Haddam iolite, as de- 
. termined by Dr. Txomson. I verified the aqueous content of 
the chlorophyllite, and in so doing observed, that the powdered 
mineral, both before and after ignition, corresponded very exactly 
with that of the Haddam pinite. 
By the reader of my treatise on Mineralogy, it will be observed 
that I referred the Haddam mineral, as well as that from Lan- 
caster, Massachusetts, and the F'rengh pinite, to the species mica. 
Inow relinquish that opinion, although I am not equally satisfied 
that the minerals from the two last localities belong to iolite,as 1 
the case of those which form the subject of the present notice. 
New Haven, July 15, 1841. | 
ed 
Arr. XIL—Steam Navigation to the Pacific by the Isthmus f 
Panama and along the Western Coast of South America. 
Some interesting pamphlets on the subject named in the title 
were placed in our hands early in 1840 in Boston, by a brother of 
Mr. William Wheelwright, to whom mainly the world is indebt- 
ed for an undertaking which may be with propriety ranked the 
first among the enterprises by steam. Mr. Wheelwright has la- 
bored several years at this undertaking and is now on the eve of 
success. From himself we have just received a communicatio?, 
which, although not intended for the public eye, contains many 
facts in which the world is interested, and we therefore venture 
to annex certain portions of his letter or abstracts from it. 
' Talcahuano, March 8th, 1841. 
= TO PROFESSOR SILLIMAN. 
Dear Sir—I had the honor of receiving your valued favor only 
a day or two since, having left the United States about the tmé 
_ it was written, to take up the superintendence of the *9¢"™ 
