1878.] 



President 's Address. 



65 



organism of plants can be traced to compounds of that element which 

 had been supplied to them ; and accordingly that there are no grounds 

 for believing that plants can assimilate the free nitrogen of the air. 



By awarding to Boussingault the Copley Medal, we place his name 

 in the honoured list of those who, in modern times, have rendered the 

 highest services to the advancement of natural knowledge. 



A Royal Medal has been awarded to Mr. John Allan Broun for his 

 investigations during thirty-five years in magnetism ,and meteorology, 

 and for his improved methods of observation. 



When the labours of Gauss had given an impetus to the study of 

 terrestrial magnetism by rendering precision possible, Observatories 

 devoted to this branch of research, in conjunction with meteorology, 

 began to rise in various places. The late General Sir T. M. Brisbane 

 erected one at Makerstown, in Scotland, and placed it under the direc- 

 tion of Mr. Broun, who remained in charge of it from 1842 to 1850. 

 His observations and their results, have been commended by magne- 

 ticians and meteorologists, for the skill employed in the development 

 of new methods of reduction and investigation. 



In 1851 Mr. Broun went to India to organize and take charge of a 

 similar Observatory established at Trevandrum by His Highness the 

 late Rajah of Travancore. Here he remained for thirteen years, 

 accumulating results of very great value, the first instalment of which, 

 consisting of a volume on the magnetic declination, was published 

 some years ago. Magueticians look eagerly towards the completion 

 of this publication when the means necessary for the purpose shall 

 have been furnished to Mr. Broun. 



While in India he established an Observatory on a mountain peak 

 6,000 feet above the sea, and fitted it up with a very complete assort- 

 ment of scientific instruments. This was an undertaking of a very 

 arduous nature, effected in a wild country, and presenting great diffi- 

 culties in the erection of instruments and obtaining trained observers. 



Shortly after the commencement of magnetic observatories, Mr. 

 Broun indicated the insufficiencies of the methods then in use for 

 determining coefficients and correcting observations, and he devised 

 new methods for these ends, the principal of which have been gene- 

 rally adopted. 



This is not the place in which to give a complete catalogue of Mr. 

 Broun's researches in magnetism and meteorology, extending as they 

 do over a period of thirty-five years, but I may indicate those of his 

 results that are of the greatest importance. Among them are the 

 establishment of the annual laws of magnetic horizontal force, 

 exhibiting maxima at the solstices and minima at the equinoxes. 

 Mr. Broun was also the first to give in a complete form the laws of 

 change of the solar-diurnal variation of magnetic declination near the 



VOL. XXVIII. p 



