Be 
APPENDICES. 593 
Additional Instructions from the Hon. Alex. H. H. Stuart, 
Secretary of the Interior, explanatory of the foregoing. 
DEPARTMENT OF THE INTERIOR, 
November 4, 1851. 
Sm: As some ils es has arisen with regard to the instrue- 
tions communicated in my letter of the 23d of October, 1850, I deem it 
proper to add such explanations and modifications as the circumstances 
seem to demand; and as Brevet Major Wm. H. Emory, the Chief As- 
tronomer, has been appointed by the President the Surveyor, under the 
treaty, to run and mark the boundary line between the United States 
and Mexico, in place of A. B. Gray, Esq., some further explanations re- 
Specting his position and duties are necessary. The officers and mem- 
bers of the scientific corps immediately connected with the survey of the 
boundary line shall be placed under the immediate orders of the sur- 
. veyor. Any lines agreed upon by the Joint Commission as the lines of 
boundary, shall be run and astronomically determined by the surveyor. 
He will have charge and direction of all the surveys of the boundary 
line, and shall determine the Initial and intermediate points of the sur- 
vey by astronomical means, acting under your direction. This corps 
shall consist of such number of assistants as you, upon advising with 
him, may deem absolutely necessary. He shall issue his instructions in 
writing, and shall preserve a copy of them in a book kept for that pur- 
pose. He shall require monthly reports from the heads of parties, and 
shall place them before you in acondensed form. He shall have charge 
of the surveying and astronomical instruments; and for their safe keep- 
ing, will be responsible to you. He shall be allowed a clerk, whose 
salary shall not exceed that of a sub-assistant. He shall be responsible 
to you, and through you to this department, for as rapid a prosecution 
of the surveys, and for all the astronomy connected with them, as may 
be consistent with their accuracy; and will be held accountable for all 
the quarter-master’s stores, camp and garrison equipage, placed at his 
Should any doubts arise between yourself and the Mexican Commis- 
sion, the surveyor shall be required to make such surveys and maps as 
may tend to elucidate the point or line in dispute. 
Should the surveyor at any time differ with your views on any 
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