SCIENCE. 



123 



Resolved, That the Association feel and would hereby express 

 the great loss which this service has suffered in the recent death of 

 its chief officer, General A. J. Myer, whose energetic administra- 

 tion of novel duties, seconded by his able corps of scientific 

 assistants, has comm inded universal respect at home and abroad. 



Professor N. P. Lupton, of Vanderbilt University, was 

 added to the committee on the best methods of scientific 

 teaching in the public schools. The following were chosen 

 a committee on the registration of deaths, births and mar- 

 riages : E. B. Elliott, F. B. Hough, J. B. Kellebrew, 

 Joseph S. Copes and E. T. Cox. 



It was voted yesterday to accept the invitation from 

 Montreal for the meeting of the Association in 1882. 



CONCLUSION. 



The sections had all adjourned in the afternoon. In the 

 evening a general session was held in Huntington Hall, 

 President L. H. Morgan in the chair. About 250 ladies and 

 gentlemen were present. A com nittee was appointed to 

 confer with the President of the United States on the ap- 

 pointment of a chief signal officer. The committee includes 

 Professors Brush and Barker, Dr. Bell, President Gilman, 

 Professor Harkness, Mr. L. H. Morgan, Professor Clarke 

 and Mr. A. Hall. The Association voted its thanks to those 

 who had helped toward making the re-union of 1880 so 

 pleasantly successful. The respective resolutions were 

 supported bv remarks from Professor Harkness, Judge 

 Henderson, Professor Nason, the Rev. Mr. Shackelford, 

 Professor Lattimore, Dr. J. Lawrence Smith, the Messrs. 

 Hoveyand Procter, and from the chair. The American As- 

 sociation for the Advancement of Science was then pro- 

 nounced adjourned, to meet again, for the thirtieth time, at 

 Cincinnati, on the 17th of August, 1881. 



We continue the publication of the addresses, and offer 

 this week that by Dr. Asaph Hall, of Washington, and the 

 Eulogy, by Professor A. M. Mayer, on the late Pro- 

 fessor Joseph Henry, both of which we present in full ; 

 also abstracts from the following papers prepared 

 by the authors : — The Photophone, by A. G. Bell ; 

 Mounds of Illinois, by William McAdams ; Determination 

 of the Comparative D mensions of Ultimate Molecules, by 

 W. N. Norton ; Plan of the Cerebro-Spinal Nervous System, 

 S. V. Clevenger ; Observations of the Planetary Nebulae, by 

 E. C. Pickering ; Co-efficients of Gas Solutions (Cut) 

 by E. L. Nichols and A W. Wheeler; The Wyan- 

 dottes, by J. W. Powell ; Ancient Agricultural Imple- 

 ments of Stone, by William McAdams ; The Endo-Cranium 

 and Maxillary Suspensorium of the Bee, by George Mac- 

 loskie ; Further Notes on the Pollination of Yucca, and on 

 Pronuba and Prodoxus, by C. V. Riley ; Simple Device for 

 Projecting the Vibration of Liquid Films without a Lens, 

 by H. S. Carhart ; On LandSnailsof the Palaeozoic Period, 

 by J. W. Dawson ; The Structure of Mica Veins in North 

 Carolina, by W. C. Kerr ; Transformation of Planorbis, by 

 A. Hyatt ; The Languages of the Iroquois, by Mrs. E. A. 

 Smith. 



ADDRESS BY PROFESSOR ASAPH HALL. 



Fellow-Members of the Association : — 



Astronomy, in some of its forms, reaches back to the 

 most distant historical epochs, and the changes that it has 

 undergone during this long lapse of time give to this 

 science a peculiar interest. In no other branch of human 

 knowledge have we such a long and continuous history of 

 the search after truth, of the painful struggle through which 

 men have passed in freeing themselves from theories ap- 

 proved by the wise of their own times, and in overthrowing 

 beliefs which had become incorporated into the life and 

 culture of those times. Perhaps the grand array of the 

 heavens, and the vast phenomena which they display, nat- 

 urally led men to the invention of complicated theories ; 



but these passed away at last before the test of observation, 

 and the criticism of sceptical men ; and the Copernican 

 theory of our solar system, Kepler's laws of elliptical mo- 

 tion, and the Newtonian law of gravitation, gave to Astron- 

 omy a real scientific character. 



The discovery of the laws that govern the motions of the 

 heavenly bodies, and the construction of the theory of these 

 motions, demanded from practical Astronomy better ob- 

 servations and a more accurate determination of the 

 orbits of the planets and the moon, or of the constants that 

 enter into the problems of celestial mechanics ; and this 

 demand led to an improvement in the instruments, and in 

 the art of observing. The astronomers and instrument- 

 makers of England and France led the way in these im- 

 provements. The great national observatories of those 

 countries were established, and in England Flamsteed and 

 Sharp, Bird and Bradley, were foremost in raising practical 

 Astronomy to the condition of satisfying the demands of 

 theory. But theoretical Astronomy was soon to receive a 

 wonderful advancement. Perhaps no one contributed 

 more powerfully to this progress than Lagrange. The 

 writings of this man were models of simplicity and elegance, 

 and yet so complete and general are his investigations 

 that they contain the fundamental theorems of celestial 

 mechanics. By the invention and perfection of the method 

 of the variation of the arbitrary constants of a problem, and 

 by the establishment of the differential equations of a 

 planetary orbit depending on the partial differential coeffi- 

 cients of a single function, Lagrange reduced the question 

 of perturbations to its simplest form, and gave the means 

 of deducing easily the most interesting conclusions on the 

 past and future condition of our solar system. To supple- 

 ment this great theorist there was needed another kind of 

 genius. Combining the highest mathematical skill with 

 unequalled sagacity and common sense in its application, 

 Laplace gathered up and presented in a complete and prac- 

 tical form the whole theory of celestial mechanics. Be- 

 sides his numerous and brilliant discoveries in theoretical 

 Astronomy, Laplace gave us some of the finest chapters 

 ever written on the theory of attraction,* and a complete 

 treatise on the calculus of probability. 



By such labors as these the questions of Astronomy were 

 brought into order and classified, and the attention of As- 

 tronomers was directed better than ever before to the de- 

 termination of the quantities which must be found from 

 observation. Moreover, the refinement of analysis and the 

 completion of theory brought out new and more delicate 

 questions, not less interesting, and requiring more com- 

 plete investigation and more powerful instruments. The 

 careful examination and study of the instruments and 

 methods of observation became necessary, as well as com- 

 plete and rigorous methods of reduction ; and finally there 

 was needed a critical and satisfactory method for the dis- 

 cussion of observations. For these last improvements in 

 Astronomy we are indebted chiefly to the astronomers and 

 mechanics of Germany. 



Among those who contributed by means of their optical 

 and mechanical skill to furnish Astronomy with the instru- 

 ments necessary for its further advancement, no one holds 

 a more honorable place than Joseph Frauenhofer. This 

 man began his scientific work at the age of twenty-two, and 

 died at thiity-nine, and yet in those seventeen years he 

 gave to Astronomy great improvements in the manufacture 

 of optical glass, driving clocks for equatorials, and tel- 

 escopes and micrometers, that in the hands of Bessel and 

 Struve gave to observations a degree of accuracy hardly 

 thought of before. To such men as Frauenhofer and his 

 co-workers, who have carried on and improved the con- 

 struction of instruments of precision, practical Astronomy 

 owes much ; and yet, after all, the principal thing in a 

 science is the man himself. No matter how excellent the 

 instruments may be, the question whether they shall be 

 used for the advancement of the science, and shall con- 

 tribute the full value of their peculiarities to help towards 

 increasing the accuracy of astronomical determinations. 



* " Ein schones Document der feinsten analytischen Kunst,"— Gauss 



