96 



Ocean Magnetic Observations, 1905-16 



Double weight was given to the results with R3C for Cruise III for the reason that 

 the dechnation deviation-coefficients were much better determmed for the R3C position 

 on the observing bridge than for the D2 position. 



The weighted mean value of the incUnation was obtained by assigning the weight 2 

 to the result of each dip needle and the weight 1 to the result of each complete observation 

 of deflected dip. Hence, the deflected dip-results from long and short distance each 

 received a weight of 1, or if the observation at one distance was repeated the result received 

 a weight of 2. The weighted mean value of the horizontal intensity was obtained by 

 assigning weights 3, 2, and 1 to the deflector results, the sea-dip-circle results by deflec- 

 tions, and the sea-dip-circle results by loaded needle, respectively, when they were obtained 

 under normal sea conditions. But when the observations were made under unfavorable 

 conditions of motion, or with small values of the horizontal intensity, the weights assigned 

 were then 6, 4, 1 in the same order. In some exceptional cases equal weights were assigned 

 the results obtained by deflector and by sea dip-circle, deflected dip, or loaded dip, as in the 

 case of swings, exceptionally quiet conditions, etc. 



DISTRIBUTION OF STATIONS. 



Table 40 shows for each cruise of the Galilee the number of days consumed (adding 

 to the days at sea those spent in the harbor-swings of vessel), the length of the cruise in 

 nautical miles, the number of tabulated values, respectively, of declination, mclination, 

 and horizontal intensity, next the average time-interval between observations, as well as 

 the average distance apart. It will be seen that, for the total length of the Galilee's 

 three cruises (63,834 nautical miles in the Pacific Ocean), the magnetic observations, 

 whether of dechnation, inchnation, or horizontal intensity, were made, on the average, 

 every two days apart in time and about 200 miles in distance. 



Table 40.— Summary shotving the Distribution of the Galilee Magnetic Observations 1905-1908. 



OBSERVERS AND COMPUTERS. 

 The Table of Ocean Results differs from the Table of Land Results, published in Volumes 

 land II,m one'other respect besides those akeady shown m the foregoing explanations, viz, 

 that the observers' initials, for practical reasons, had to be omitted. The magnetic 

 results for any one day are the combined product of all the observers aboard at the tune. 

 Those who took part in the observations for the various cruises of the Galilee are as follows : 

 Cruise /.— J. P. Ault, L. A. Bauer, J. H. Egbert, J. F. Pratt, and P. C. Whitney. 

 Cruise II.— J. P. Ault, H. E. Martyn, J. C. Pearson, and W. J. Peters. 

 Crtiise III.—?. H. Dike (beginning August 1907), J. C. Pearson (to July 1907), 

 W. J. Peters, G. Peterson, and D. C. Sowers. 

 The chief persons who have taken part, at various times, in the comparisons and 

 determination of instrumental constants at Washington, in the final office reductions, or 

 in the preparation of results for pubhcation, are: J. P. Ault, L. A. Bauer, J. J. Carey, 

 P. H. Dike, C. R. Duvall, H. M. W. Edmonds, C. C. Ennis, H. W. Fisk, J. A. Fleming, 

 H. D. Harradon, H. F. Johnston, R. R. MUls, J. H. Millsaps, J. C. Pearson, W. J. Peters, 

 A. D. Power, H. R. Schmitt, D. C. Sowers, and J. A. Widmer. Those whose names are 

 itahcized have borne the brunt of the work at Washington. 



