44 



Ex. Doc. No. 41 



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49j at the Alameda; camp 51, at Peralta, at the mill, aiid I shall ** 

 establish two more, one at Taos, and the other at Secoro. .^ 



These points are quite sufficient, and will be the base of your 

 operations; and upon them you will form a Irigonometric canevas. 

 For this purpose the rule requiring every angle of the series to be 

 greater than 30% may be wholly disregarded. 



And after having 



determined by triangulation the position of any three conspicuous 

 peaks, the position of any other points, which are in view of the 

 three first named, may be determined by the problem'of three point?, 

 as is practised in hydrographic surveys* Many such points will 

 present themselves, ^ . ■ 



The canevas completed, the course' of the Del Nortej that of its 

 tributaries to the base of the mountains or beyond the settlements; 

 the width of the valleys; the quantity of land under cultivation; 

 the position of the towns, churches, hills, and all other topogra- 

 phical features of the country, can be determined with the Schmal- 

 kalde's compasses. ^ ' . 



If your force is sufficient, the operation described in this last 

 paragraph may be carried on simultaneously with the triangulation. 

 You are aware that I have no theodolite at my disposal, the tria^n- 

 gulation must, therefore, be made with the sextant. 



The population, number of cattle, horses, and sheep, and the 

 quantity of grain and other agricultural products, the facilities and 

 best localities for water power to propel machinery, and. also the 

 mineral resources of the country, it is very desirable to know. 

 You w^ill, therefore, give particular attention to acquiring all the 

 information on these subjects which the present statistical know-: 

 ledge in the country will afford. 



A requisition for five'^ho'Ssand dollars will be made on the Bureau 

 of Topographical Engineers for the survey, to be placed to your 

 credit with Mr. Robert Campbell of St. Louis, upon whom, I should 

 think, you might safely draw, without waiting to hear from Wash- 

 ington. 



I made a requisition on the bureau, dated June 18, 1S46, for a 

 transit instrument, and also for an instrument to obtain the magne- 

 tic dip and declination. Sho.uld these arrive, you will unpack them, 

 mount the instruments near the place where I observed in Santa 

 Fe, and commence a series of observations for longit-ude by moon 

 culminating stars, and for the magnetic dip and declination. 



The series for longitude will b^e continued for at least three luna- 

 tions, and, .should an opportunity present itself, I wish the observa- 

 tions and results to be communicated to me in California. 



I am, very respectfully, your obedient servant, 



W. H. EMORY, 



First Lieut. Corps Top. Engineers. 

 Lieutenant J. W. Abekt, or, in his absence, 

 Lieutenant W. G. Peck- 



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