ADDRESS OF THE PRESIDENT. 55 



The branch of Astronomy tliat was practically unknown af the I)oj>inaing 

 of the century — that of spectrum analysis — has durins; the century assumed 

 the most far-reaching proportions. The discovery in 1814 of the many dark 

 lines in the light of the sun and also in the stars marked the beginning of 

 spectroscopic astrononiy. 



The chemistry of the sun Ijegan to be known and now thirty-nine of the 

 elements found on the earth have been found in the sun. Helium was found 

 in the sun before it was discovered on the earth. Exhaustive studies of the 

 spectra of the stars, nebulae and comets have been made, so that we know 

 much about the composition of the various heavenly bodies. With the spec- 

 troscope, the approach or the recession of a star can be determined together 

 with the velocity of the same. 



Another method of astronomical study that has become exceedingly 

 valuable is that of celestial photography. It must be borne in mind that the 

 art of photography was not known until 1830 when Xiepce and Daguerre 

 founded this art. Its marvelous development is well known. The astronomer 

 soon recognized how this art might be made use of in celestial study. The 

 first celestial ob eet to be photographed was the moon in 1840 by Dr. J. W. 

 Draper, and the sun in 1845 by Foucault and Fizeau. The first photograph 

 of a star was that of Vega in 1850 at Harvard. The total eclipse of the sun of 

 1860 was photographed. The first photograph of the spectrum of a star 

 was made in 1872 by Henry Draper. Long exposures have become an im- 

 portant feature, the time occasionally reaching forty hours. Time will not 

 permit me to more than mention the great advances made in cataloguing the 

 stars, finding out the distances of the heavenly bodies, determining much 

 concerning stellar evolution as a result of spectroscopic investigation, and the 

 science of thermo-dynamics, the discovery of some close relationship 

 between the solar and terrestrial weather, and the really marvelous achieve- 

 ments in the realm of higher mathematics by such men as Adams, LeVeiTier, 

 and Neweomb. 



II. Chemistry. 



A century ago, our knowledge of Chemistry was indeed very primitive. 

 The studies in this line were shrouded with the mysterious and hence were 

 lost in the thoughts of alchemy. The beginning of real Chemistry, however, 

 had been made. Oxygen, hydrogen, and chlorine had been discovered. The 

 bleaching power of chlorine had been demonstrated and applied in the manu- 

 facture of cloth. A few of the organic compounds such as lactic, citric, malic, 

 oxalic, and gallic acids had been discovered. Most of this work had been 

 done by Scheele. Then came the work of the foimder of modern chemistry, 

 that of Lavoisier. His greatest work, probably was the overthrow of the 

 phlogiston theory, which paved the way for the true conception of combustion. 

 With this settled there was a chance for the development of true chemical 

 relations. 



