200 THE POPULAR SCIENCE MONTHLY 



way in which this particular project, and similar ones to it, could not 

 only be expeditiously conducted, but so as to realize the chief objects 

 of the work. Judging from individual expressions received from 

 scientific men everywhere, they appear in agreement with u.s. This 

 policy, briefly stated, is: To make, with the aid of the friendly and 

 harmonious cooperation of all concerned, a rapidly executed magnetic 

 survey of the greater part of the globe, so that a general survey, all- 

 sufficient for the solution of some of the great and world-wide prob- 

 lems of the earth's magnetism, will be completed within a period of 

 ten to fifteen years. At a smaller number of points, selected in con- 

 sideration of the prime questions at issue, the observations are to be 

 repeated at intervals of five years or less, in order to supplement the 

 rather sparsely distributed magnetic observatory data. Thus the de- 

 termination of the corrections for reduction of the general work to 

 any specific date is continuously provided for. 



Now, had I the time or were this 'the place, I should like to add 

 a paragraph regarding the needful accuracy and the prime questions 

 to be considered in the conduct of such a piece of work. Permit me to 

 say that the most evident result of all magnetic work in the past is that, 

 for the purposes of a general survey, it is far better to make some 

 sacrifice in accuracy if thereby it is made possible to secure observations 

 at another point. In other words, the errors due to local disturbing 

 conditions are far greater than the purely observational ones. Hence 

 multiplicity of stations rather than extreme accuracy and laborious 

 methods of ohservation and reduction is the prime requisite in mag- 

 netic survey work. 



Stimulants to Eesearch "Work 

 Dr. Gilman, in his charming reminiscences of the non-resident 

 lecturers of the Johns Hopkins University, related the following of 

 the great mathematician Sylvester: 



Sylvester enjoyed stimulants — I do not mean such vulgar and material 

 articles as alcohol and coffee. I never saw any indications that he cared for 

 their support. But he loved such stimulants to intellectual activity as music 

 and light, lively society, in which he was not called upon to participate. Once 

 at a symphony concert I sat just behind him, admiring the dome of his capacious 

 cranium, unconcealed by hair, and I noticed how absorbed he was. The next 

 day, Sunday, he came to me impetuously to say that he had worked out some 

 mathematical proposition at the concert of the evening before, the music having 

 quickened his mathematical mind. He really thought this was his greatest 

 achievement yet, and he had hastened to write it out and mail it to the Academy 

 of Sciences in Paris. Once he told me that, having a special paper to prepare, 

 he went to a store and bought a pound of candles, which he placed about his 

 room, on all sorts of extemporaneous candlesticks; "for light," he said, "is 

 a most powerful tonic." 



These anecdotes will serve to recall similar ones of noted men. 



