APPENDICES. 601 
tember, 1849. Thus is completed a consecutive chain of magnetic sta- 
tions extending from the observatory at Cambridge, Massachusetts, by 
way of Galveston, San Antonio, and El Paso del Norte, to the Pacific 
Ocean. At most of the stations, the three elements, inclination, declina- 
tion, and intensity have been observed. In the astronomical and mag- 
netic department, John O'Donoghue and Hugh Campbell have been 
my invaluable assistants. 
The magnetic instrument used was made by Mr. George, of Fal- 
mouth, under the direction of the celebrated Mr. Fox, the inventor. It 
is the same that was turned over for this service by yourself at the close 
of the North-eastern Boundary survey. With it I observed at Chagres, 
Gorgona, and Panama, in 1849. 
It is believed that a map exhibiting the results obtained will prove 
of much interest, and when published will add credit to the department 
under which the operation has been conducted. I regret that we have 
not the power of embracing the present opportunity—by returning to 
the United States by way of China and the Mediterranean—to sur- 
round the globe with a series of magnetic observations. Not only 
would the value of the results upon the boundary be greatly enhanced 
by such direct comparison at European observatories, but passing 
through or near the maxima of horizontal intensity, the lines of no vari- 
ation would be crossed, and an exceedingly interesting belt of observa- 
tions might be completed around that part of the world, at present, 
with reference to magnetism, so little known. 
Notwithstanding the recent hostility of the whole tribe of Apaches, 
Colloteros, Pinal Llefios, and Tontos, through which we passed without 
an escort, nothing but kindness was received from them. The Yumas 
and Cocopas, though glorying in the belief that they had driven away 
the small detachment of United States troops stationed among them, 
still treated us with respect and favor. The vigilance of Colonel Craig 
gave them no opportunity of showing hostility. 
One sad accident I have to record: the death of Thomas Harper, an 
excellent young man from Kentucky, and a member of my party. 
While bathing in the Colorado, he was seized with cramp, sank, and, 
although a dozen leaped into the water to afford assistance, the rapid 
current bore him beyond reach, and search was fruitless. 
Major Heintzelman is now preparing to establish the military post 
at the Colorado River. Soon as this is done, I hope to be able to ob- 
