i66 REPORTS OF inve;stigations and projects. 



declination on both helms and 3 on one helm ; 34 for horizontal intensity by 

 deflector on both helms and 4 on one helm; 17 for intensity by Lloyd-Creak 

 dip-circle on 2 helms and 17 on one helm; and 17 for dip on one helm, in ad- 

 dition to which dip values were derived from the intensity work with the 

 Lloyd-Creak dip-circle on 34 swings of one helm each. 



Astronomical observations for position with dead reckoning, involving 

 some 1,600 observation and computation sheets, daily intercomparisons of 5 

 chronometers, and daily meteorological observations were made. Experi- 

 ments were carried out in connection with a design suggested by the com- 

 mander of the Galilee, of a "collimating liquid compass" for sea work, which 

 seem to indicate the feasibility of such an arrangement for the improvement 

 of the magnetic-declination work. Further experimentation is being made in 

 the instrument division of the Department. Some experiments were also 

 made for improvement in the methods of intensity observations at sea. 



In addition to his duties as magnetic observer, Mr. P. H. Dike made obser- 

 vations of the electrical condition of the atmosphere at sea, whenever condi- 

 tions and time permitted. His report, summarizing the results obtained, 

 will be found in the September issue of the Journal, "Terrestrial Magnetism 

 and Atmospheric Electricity." The conclusions drawn are : 



While the work done has served mainly to point out the difficulties to be 

 encountered in using the present types of electrical instruments at sea, still 

 some information has been accumulated which may be of value in connection 

 with future work undertaken in similar fields. Also, the probability that the 

 earth-air electric current is of the same order of magnitude over the sea as 

 over the land has been strengthened. In the neighborhood of land, as off the 

 coast of Alaska and in Cook Straits, the observations showed conclusively the 

 presence of radioactive emanation in the air, but in the open sea there is but 

 little evidence. Rain-water, caught as it fell and immediately evaporated to 

 dryness, showed no sign of radioactivity. 



The personnel of the Galilee party remained the same throughout the por- 

 tion of Cruise III here concerned, viz, William J. Peters, commander ; P. H. 

 Dike and D. C. Sowers, magnetic observers ; Dr. G. Peterson, recorder and 

 surgeon ; and J. T. Hayes, sailing master. The volume of work accomplished, 

 as well as its high quality and the promptness in reduction and forwarding 

 of the observations, all bear ample testimony of good management on the part 

 of the leader and of the hearty and effective cooperation of every member of 

 the party. 



The return of the Galilee to her home port, San Francisco, after an absence 

 of nearly 3 years, during which time she has cruised in the Pacific Ocean, as 

 shown on plate 11, to the extent of over 60,000 nautical miles, in regions 

 where magnetic data were very scarce, brings to a conclusion the first portion 

 of the ocean magnetic work. During this period, a general magnetic survey 

 of the greater part of the Pacific Ocean has been accomplished. It may con- 



