22 



Prof. F. Elgar. On the 



[Jan. 14, 



should filter out injurious rays, &c, living organisms could hardly 

 endure the solar light. 



Pringsheim operated on chlorophyll tissues. By means of a lens 

 and a heliostat he concentrated upon them sunlight, from which by 

 suitable media he had sifted out the heat rays. In a few minutes the 

 green colouring matter was destroyed, the protoplasmic circulation 

 arrested, the protoplasm disorganised, and the cell flaccid and inert. 

 He found, as we had found, that the more refrangible rays were the 

 most powerful, and he, too, concluded that he was dealing with an 

 oxidation, for in an atmosphere of hydrogen or of carbonic acid these 

 destructive results no longer ensued. 



The experiments of Siemens* and Deherainf also demonstrate both 

 the destructive influence of the electric light on vegetation and the 

 protective effect of a glass screen. 



[Note. — According to an abstract in " Journal of Science," 3rd 

 ser., vol. vii, p. 594, M. Duclaux has since published the results of his 

 observations on six species of micrococci, apparently of pathogenic 

 kind.} 



Forty days of insolation (May 4 — June 13) proved sufficient to kill 

 and less to attenuate these germs in the moist state. In a desiccated 

 condition eight days (May 26 — June 3) proved fatal ; in July none 

 resisted three days' exposure at a south window which received the 

 sun only from nine to one o'clock each day, and where the tempera- 

 ture did not exceed 102° P. (39° 0.). Fifteen days of July sun 

 destroyed the micrococci in the moist state. He had not in these ex- 

 periments eliminated any partial influence of temperature. January 

 4, 1886.— A. H. D.] 



II. " Notes upon the Straining of Ships caused by Rolling." By 

 Francis Elgar, LL.D., F.R.S.E., Professor of Naval Archi- 

 tecture and Marine Engineering in the University of 

 Glasgow. Communicated by Sir E. J. Reed, F.R.S. 

 Received December 28, 1885. 



(Abstract.) 



It does not appear that any serious attempt has yet been made to 

 investigate the amounts, or even the nature, of the principal straining 



* " Rep. Brit. Assoc.," 1881. 



f " Journ. Cliem. Soc," (Abst.), Jan., 1883. Considerations of time and space 

 prevent me from noticing many other observations of interest in connexion with, this 

 subject; e.g., of Engelmann on Pelomyxa ("Arch. f. Phys.," xix, 1879) and on 

 B. pJiotometricum ("J. Roy. Micr. Soc," Abst., 1882-2), or of Stahl, "On the 

 Arrangement of Chlorophyll Bodies in Plant-Cells" ("Bot. Zeit.," 1880). 



X " Comptes rendrs," 1885. 



