REPORT OF THE PRESIDENT, I9IO. 29 



telescopic apparatus. Their appreciation of these opportunities and of the 

 optical perfection of the telescopes, particularly of the 60-inch equatorial 

 reflector, is a source of keen encouragement to the observatory staff. 



Attention is invited to the interesting account given in the departmental 

 report of the numerous investigations now under way at the observatory 

 and in the physical laboratory at Pasadena. They are so effectivly summa- 

 rized in this report that any restatement appears superfluous. 



No department of research in the Institution is conducting work which is 

 at once so obviously practical and so obviously theoretical as the work of the 

 n Department of Terrestrial Magnetism. Every one ac- 



Terrestrial quainted with the daily use of the compass in exploration, 

 Magnetism. j n surveying, and in navigation recognizes the practical 

 utility of a magnetic survey of the erth. But those who recognize that any 

 utilitarian results may come from a deeper knowledge of the erth's mag- 

 netism and its cosmic connections are at present very limited in number. 

 Nevertheless, the history of science warrants a confident expectation that the 

 latter results will ultimately prove to be of much greater value than the 

 former. 



The more striking events of the year in this department refer naturally to 

 the non-magnetic ship Carnegie, which was off on her first cruise at the close 

 of the previous fiscal year. She was then at Falmouth, England, where her 

 determinations of the magnetic elements were compard with independent 

 determinations made at the permanent magnetic observatory of that port. 

 She proceeded thence, November 9, 1909, to Funchal, Madeira; thence to 

 Hamilton, Bermuda ; and thence, under tempestuous conditions which provd 

 her seaworthiness, to Brooklyn, N. Y., where she arrivd February 17, 1910. 

 Here she had her copper sheathing applied by the constructors, as requird 

 by their contract, and was overhauld and refitted for a three years' circum- 

 navigation cruise. It is a pleasant duty to report that in all essential respects 

 this vessel has proved more effectiv than was anticipated. It has been dem- 

 onstrated that even in rough weather the three magnetic elements (declina- 

 tion, dip, and intensity) may be determind with a precision little short of that 

 attainable in a fixt observatory. Thus she was able to discover on her first 

 cruise errors of unexpected magnitude in the best sailing charts of the north 

 Atlantic, and she is certain to attain at least an equal degree of precision in 

 all future ocean work. By crossings of her own tracks and by connections 

 at all available ports having magnetic observatories it will be practicable to 

 exclude the possibilities of any important errors in this work. 



Similarly satisfactory progress has been made also in the land work of the 

 department during the year. The expedition in Africa, from the Cape to 

 Cairo, undertaken by Dr. Beattie and Professor Morrison as temporary 



