394 



SCIENCE 



[Vol. V., No. 119. 



Among the wonderful achievements of 

 modern explorers should be placed on record 

 the history of the successful expedition of 

 Capt. Willard Glazier in search of the ulti- 

 mate source of the Mississippi River. This 

 daring explorer, at the head of a large and 

 well-equipped party, penetrated the untrodden 

 wilderness of central Minnesota, and reached 

 Lake Itasca, which has so long been regarded 

 as the source of the great river. Not content 

 with this achievement, he plunged boldly into 

 the forest, and succeeded, after great exertions, 

 in forcing his way three miles farther south- 

 ward, where he came to a second lake, also 

 drained by the Mississippi, and forming, as he 

 states, its uttermost head. To this lake he 

 gives his own name, that the fame of his 

 achievement ma}' be perpetuated. It is per- 

 haps unfortunate, that, as this whole region 

 was sectionized by the general land-office sev- 

 eral years previously, lines having been run at 

 eveiy mile, a prior claim to this great discov- 

 ery may arise. In an} T case, however, the 

 names of Capt. Glazier and John Phenix as 

 explorers will go down to posterity side by 

 side. 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good faith. 



The new commissioner of agriculture. 



In your notice, April 10, of the appointment of Col 

 Coleman to be commissioner of agriculture, you com- 

 mend the selection because of his " knowledge of 

 practical agriculture, and his experience of men and 

 affairs," and indirectly condemn it because he does 

 not have "any special or intimate acquaintance with 

 the science of agriculture;" your idea seeming to 

 be that the agricultural department should be organ- 

 ized as a ' scientific bureau, with a technical expert 

 at its head.' 



Col. Coleman has one additional qualification, in 

 which he differs from all previous commissioners: 

 he is without a pet hobby. His course will be to 

 elevate the work of the bureau from the advocacy of 

 some single theory, to the development of what is 

 best in a variety of theories, and the adaptation of 

 that best to the practical work of the agriculturist. 

 To carry out such a course, it is not necessary that 

 the head of the bureau should be a ' technical ex- 

 pert:' indeed, it is better that he should not be. 

 Technical experts in one or two or three branches 

 of scientific agriculture are, as a rule, those gentle- 

 men who have bees in their bonnets, and seem to be 

 incapable of such universal control as ought to be re- 

 quired ; and experts in all branches cannot be found. 

 If one have the ability to distinguish and recommend 



what is best, to discover and make use of the ability 

 of specialists, to restrain the disposition in any one 

 department of his general work to override or belittle 

 the rest, that one is the person to have charge as the 

 general head. Such a person is Col. Coleman. His 

 experience of men and affairs, and the general ap- 

 preciation of his fitness in the conditions you pointed 

 out, by all classes of men, prove the wisdom of the 

 selection. 



When the bureau is to be properly organized as a 

 scientific one, will be after the so-called agricultural 

 colleges, founded at so enormous an expense by the 

 general government, shall have done what they were 

 intended to do, — raise up young men and women, 

 first, to an appreciation of what scientific agriculture 

 is capable ; and, second, to an educational ability to 

 pursue and apply it. Until the old ruts are aban- 

 doned by men capable of understanding the benefit 

 of a new and well-made road, such men to be those 

 who are practical workers themselves, there will be 

 no use of attempting science in a place the province 

 of which is really only the collation, selection, and 

 diffusion of such knowledge as can be used in the 

 gradual development of all the resources of the coun- 

 try. When the work of such an education is begun 

 at the right end, it will have its natural sequence in 

 a higher gradation of the work of the head of the 

 agricultural bureau, if any thing higher than that 

 which will be accomplished by the new commissioner 

 is needed. Aug. F. Harvey. 



St. Louis, April 19. 



Auroras. 



Various speculations are met with from time to 

 time as to the extent of any individual display of 

 an aurora. A prominent French writer has recent- 

 ly attempted to show that auroras are not widely 

 extended, and has instanced the case of the most 

 brilliant aurora of modern times at Brussels, Belgi- 

 um. This phenomenon occurred on Feb. 4, 1872; 

 and the writer emphasizes the fact that it was not 

 seen at Godthaab, Greenland. Meteorological obser- 

 vations at the latter place for this date are not acces- 

 sible; but there is little doubt that, if there were such, 

 it would be found that the sky was clouded, thus pre- 

 venting the appearance. At all events, the observa- 

 tions made on the American polar steamer Polaris, 

 which wintered about four hundred miles north of 

 Godthaab, show the most brilliant aurora of the 

 winter on Feb. 4. The same aurora was seen 

 throughout the northern United States. 



When we consider, that, as shown by Professor 

 Loomis, during a maximum period of sunspots there 

 are also the greatest number of auroras, and that 

 great solar outbursts are followed or accompanied 

 by magnetic storms and brilliant auroral phenomena, 

 we are led to the view that the cause of the latter 

 may be superterrestrial, acting either directly or indi- 

 rectly through induced earth-currents. 



It would seem as though all auroras are a manifes- 

 tation of cosmic energy, and that their extent and 

 brilliancy are limited by the amount of energy, by 

 the vapor in the air, by the temperature, etc. Pro- 

 fessor Lemstrom in Finland obtained a simulation of 

 the aurora by artificial means during one winter; but 

 during the next winter, which was barren of brilliant 

 auroras, both he and Professor Tromholt, the latter 

 in Iceland, failed in this. It may be that the first 

 success was owing as much to earth-currents, or a 

 condensation of atmospheric electricity, as to the 

 artificial means employed. 



The question of the source of the electricity of 

 an aurora is an important one in meteorology ; and 



