[7] 130° 
Passo, and that he must. have travelled. south of that. ridge, in an 
almost due west course to the Rio Colorado. 
ae use the word “Sierra Madre” in the sense attached to it by 
the Mexicans, viz: that ridge which separates the waters that fall — 
_into the Atlantic from the rivers which empty into the Pacific 
ocean, without any regard to its elevation 
I pray you to accept the assurances of my distinguished consid- 
eration and personal regard, ‘ 
- Your most:obedient a faithful servant, 
ALBERT GALLATIN. 
To Lieutenant W. H. Emory, 
U. S. Topographical Te pasier, Washington. 
Wasuineton, October 8, 1847. 
Dear Sir: In answer to your letter of the Ist instant, I have the 
pleasure to send you, with ‘the permission of the chief of my de- 
artment, a table of twenty-three geographical positions determined 
a myself, which you are at liberty to use; and, should you think 
the information of sufficient importance, I should feel much flat- _ 
tered that you should, as you propose, communicate them to, Mie 
Ethnological Society of New. York-for publication. ' 
o astronomical observations, that I am aware of, have ever be 
fore been made on the same grounds, if we except the observations 
of Dr. Coulter at the mouth of the Gila, which have never yet been 
published. 
ou will see that the posihiew of the Gila is very much changed, 
as well as that of Santa Fé, in New Mexic 
he observations were Be 3 with an 83 eee’ sextant, constructed 
. by the celebrated Gambey, of Paris. In most cases, the determina- 
tions 4s the places in latitude are the mean of the results obtained 
Aa y observations on north and south stars, of nearly equal 
linden, by which the errors of eccentricity, &c., in the sagetu 
ment were avoide 
ihe: longitudes a are derived from a combination of the oe 
the chronometers, and measurement of distances between the 
m oon and stars, nearly equi-distant on either side of it 
ad e chronometers used were two very good box ehsdkomeierss 
by Parkinson & Frodsham, (Nos. 783 and 2075.) 
. The observations themselves, including those between Santa Fé 
and Fort Leavenworth, (our point of departure,) in number 2,500 
or 3,000, were all computed in the field, and are now undergoing 
verification by Professor Hubbard, a very ‘accurate young camputers 
attached to the observatory at W ashington 
‘be comes tations for all the points embraced in the table sent 
“you, bave been verified. 
‘he objects of « our expedition being purely raihiy tA the subjects 
f interest to scientific men were enly pursued so far as they were 
| incidental to the expedition, and did not interfere swith: its great ob- 
ject. The ppshiuments with which I was furnished were not thosey, 
