Extracts prom Instructions, 1909-16 317 



4. Observations with sea deflector. — Continue previous method, viz, read each position twice in 

 succession and take simultaneous readings of course by Kelvin compass. Every care must be taken 

 of the magnets; they must not be handled any more than necessary. For magnet 45, read vernier A , 

 and for magnet 2L, vernier B. 



5. Shore observations with sea deflector. — Always begin and end observations by reading on mark. 

 Next read compass card before mounting deflecting magnet, and again, afterwards, for each magnet. 

 (These observations will furnish declinations, both from the undeflected and deflected positions of the 

 card.) 



6. An abstract of the ship's log for a passage, together with the monthly journal, will be trans- 

 mitted promptly to the Office. 



7. To control effectively the ship work, the computations are to be kept up to date as heretofore 

 and an abstract is to be made. Whenever discrepancies in the results, derived from the various 

 instruments and methods, appear, every effort should be made by the observers to determine the 

 cause, and to repeat the observations at the earliest moment. 



8. Atmospheric-electric observations. — The observer, in addition to the magnetic work, will under- 

 take whatever is feasible, and will conduct desired experiments, as directed, for supplementing the 

 present information as to what is necessary to make this work successful. 



9. Meteorological observations. — These observations are to be made in cooperation with the United 

 States Weather Bureau and m the same manner followed on the cruises of the Galilee. They will 

 be recorded on the forms supplied by the Bureau. 



CRUISE II OF THE CARNEGIE. 1910-1913. 

 From Route Instructions of June 4, 1910, to W. J. Peters at Brooklyn. 



1. The Carnegie will sail from Brooklyn on her next cruise (No. II) not later than the 20th 

 instant. You will please make all arrangements accordingly. 



2. You will find inclosed two copies of the Schedule of the Cruise, accompanied by a blue print, 

 showing the various courses and ports. Please note that the aim is to fill in the regions where 

 magnetic data are especially needed. * * * 



[The ports of call on this circumnavigation cruise, as finally settled upon^ were: Brooklyn, 

 Greenport (Gardiners Bay), Vieques (Porto Rico), Para, Rio de Janeiro, Montevideo, Buenos Aires, 

 Cape Town, Colombo (Ceylon), Port Louis (Mauritius), Colombo, Batavia, Manila, Suva (Fiji), 

 Papeete (Tahiti), Coronel (Chile), Port Stanley (Falkland Is.), Jamestown (St. Helena), Bahia, 

 Jamestown, Fabnouth, Greenport, and Brooklyn. The cruise was arranged with the view of 

 encountering, on the various passages, the most favorable conditions possible, as to sea and weather, 

 and having the best trigonometric conditions for the astronomical work. Consideration was also 

 paid to the desu-abihty of securing intersections with the previous tracks of the Galilee, the Carnegie, 

 the Gauss, and the Discovery. The Carnegie sailed from Brooklyn June 20, 1910, and returned on 

 December 19, 1913. For synopsis of cruise, see pages 165-170; also abstract of log, pages 333-347.] 



Instructions of June 11, 1910, for Scientific Work on Cruise II. 

 A. Magnetic Observations on Swings. 



1. En route to Vieques, Porto Rico, magnetic observations on swings are to be made in Gardiners 

 Bay at same place as in 1909 (lat. 41° 06' N. ; long. 72° 13' W.). It will suffice to secure for each ele- 

 ment one complete swing with each helm, provided all necessary precautions are taken beforehand 

 regarding absence of magnetic articles close enough to affect the results, and with respect to satis- 

 factory condition of instruments. The swings for the various elements may be arranged by the Com- 

 mander to suit the conditions; 8 equidistant headings will be taken. 



2. Declinations will be obtained with both instruments (CI and D3), especial care being taken 

 with respect to level of D3. 



3. Inclinations.— First hebn: absolute dips with D. C. 189 (needle 10), observations on each 

 heading being of same extent as for course, including reversal of polarity of needle; other helm: 

 deflected dips will be obtained from the deflection observations under 4. (See precautions as to 

 level of instrument under D3.) 



