538 Mr. E. J. Stone on Change of Climate 



are formed in accordance with the following equation : — 

 qs H s 3 + a idehyde - H 2 O = gly ceral. 

 Glycerine. 



€ 3 EH 



Acetoglyceral, H J^O 3 , is formed by heating glycerine with 

 € 2 H 4 J 

 aldehyde in closed tubes for thirty hours to a temperature of 

 170°-180°. On distilling the contents of the tubes, a body is 

 obtained which passes over between 184°-188°, and is the sub- 

 stance in question. It is a dense liquid, slightly soluble in water. 

 Freshly distilled it is almost inodorous ; but exposed to the mois- 

 ture of the air, the odour of acetic aldehyde soon appears. 

 € 3 H 5 "J C 3 Hn 



Valeroalyceral, H >0 3 , and benzoglyceral, H >, have 

 G 5 H 10 J € 7 H 6 J 



been prepared by analogous methods. 



In his general investigations on organic acids, Kekule had 

 observed that, by the action of sodium-amalgam on aconitic acid, 

 an acid richer in hydrogen was produced. This observation has 

 been pursued by Wichelhaus*, who has found that the acid thus 

 formed is identical with an acid obtained by Maxwell Simpson 

 by the action of potash on cyanide of allyle : the acid received 

 no name from its discoverer, but Kekule has proposed for it the 

 name carballylic acid. The formation of this acid from aconitic 

 acid is thus expressed : — 



C 6 H 6 6 + 2H=€ 6 H 8 6 . 

 Aconitic acid. Carballylic acid. 



LXXIII. On Change of Climate due to the Eccentricity of the 

 Earth's Orbit. 



To the Editors of the Philosophical Magazine and Journal. 



53 Harley Street, 

 Gentlemen, May 23, 1865. 



HAVE received the following communication from Mr. 

 Stone, of the Observatory at Greenwich, in reply to some 

 questions put by me to the Astronomer Royal on the subject of 

 Mr. CrolPs valuable paper "On the Physical Cause of the Change 

 of Climate during Geological Epochs/'' which appeared in the 

 August Number of your Magazine for 1864. Feeling sure that 

 it will be of use to Mr. Croli and those geologists and astrono- 

 mers who may be following up the important line of investiga- 



* Liebig's Annalen, October 1864. 



