1877.] 



President's Address. 



449 



carefully studied. Some important results were obtained by the compari- 

 son of the behaviour of the liquid nitro-glycerine and the solid pulped and 

 compressed gun-cotton devised by Mr. Abel. Among other things, the 

 detonation of gun-cutton when thoroughly saturated with water, the 

 transmission of detonation to distinct masses of gun-cotton enclosed in 

 receptacles in which the space between the masses was filled up with 

 water, and, f arther, the value of water as a violent disruptive agent (as 

 in shells) when it was caused to transmit the force generated by the 

 detonation of very small quantities of gun-cotton, which it surrounded, 

 were established. 



The last memoir published in the Philosophical Transactions, on " Fired 

 Gunpowder," is a joint production of Mr. Abel and Captain Noble; 

 and as the merit of the investigation, which has occupied the authors for 

 some years, is divided, I do not dwell particularly upon it, except as 

 affording evidence of the continuity of Mr. Abel's researches in physico- 

 chemistry, which places him at the head of all other workers in the line 

 of research which has mainly engaged his attention, and which has been 

 productive of practical results of the greatest importance to this country. 



[The Medal was received by Mr. Abel.] 



A Royal Medal has been awarded to Prof. Oswald Heer, of Zurich, for 

 his numerous researches and writings on the Tertiary plants of Europe, 

 of the North- Atlantic Islands, North Asia, and North America, and for 

 his able generalizations respecting their affinities, their geological and 

 climatic relations. 



It is mainly to Prof. Heer's labours that we owe those great advances 

 made of late in our knowledge of the Miocene, Pliocene, and Post- 

 Pliocene floras of Central Europe, which establish upon broad but safe 

 grounds the close analogy existing between the vegetation of these epochs 

 and that of the present period in Eastern North America and Eastern 

 Asia. To Prof. Heer also we are mainly indebted for the remarkable 

 discovery that a rich and varied arboreous vegetation, strikingly similar 

 to what now obtains in temperate and subtropical countries, once extended 

 to the Arctic Circle and far beyond it — a fact of which no adequate 

 explanation has been found, and the importance of which, in relation to all 

 questions as to the former geological and geographical conditions of the 

 northern hemisphere, cannot be overestimated. 



Prof. Heer's youthful studies were directed to botany and entomology. 

 His scientific authorship commenced in 1836 ; and the early bent of his 

 mind towards the higher problems of natural science is evinced by one of 

 his very first memoirs, being ' Sur la G-eographie Botanique de la Suisse,' 

 published in 1837. His earliest work on fossil plants was upon those of 

 the Rhone valley, published in 1846, since which period he has been un- 

 interruptedly and indefatigably engaged on the comparative study of 

 recent and fossil plants and insects — describing and illustrating them with 



