354 GEOEGE JOHN KOMANES 1393 



were taken from each packet, mustard, cress, beans, 

 peas, &c., being the kinds employed, and, having been 

 weighed in a chemical balance, were sealed up in 

 tubes which had previously been exhausted of air, 

 and kept exposed to the vacuum for a period of 

 fifteen months. At the end of that time they were 

 removed from the tubes and sown in flower-pots 

 buried in moist soil. In some cases, after the seeds 

 had been in the vacuum tubes for three months, 

 they were transferred to other tubes charged with 

 pure gases, such as oxygen, nitrogen, hydrogen, car- 

 bon monoxide, or with aqueous or chloroform vapour, 

 and there kept for a further period of twelve months, 

 when they were sown as before. 



In all cases the same number of seeds, of simi- 

 lar weights to those sealed up in the tubes, were 

 taken from each packet, kept in ordinary air for 

 the fifteen months, and then sown as control experi- 

 ments. 



The results clearly showed that the germinating 

 power of the seeds was hardly, if at all, affected either 

 by being exposed to the vacuum or to the atmo- 

 spheres of the various gases and vapours. Further, in 

 110 single case, in the hundreds of seeds so treated, 

 did the plants produced from them differ from the 

 standard types grown from the control seeds even in 

 the smallest degree. 



The second paper described experiments in helio- 

 tropism, which had been undertaken by Mr. Eomanes 

 with the object of ascertaining whether plants would 

 bend towards a light that is not continuous, but 

 intermittent. 



Mustard seedlings, grown in the dark until they 

 were about one or two inches high, were used in all 

 the experiments ; they were either placed in a dark 



