260 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



the day was bright but without much sunshine, so that on a 

 winter day in about Hve hours interval the alkalinity had 

 increased, as a result of photo-synthesis, from 2-4 c.c. to 5-9 c.c. 

 The bottle and the contained algae was carried over to 

 Liverpool, being exposed on board the steamer, and later on 

 the roof of the laboratory, to such illumination as was available. 

 It was titrated for a third time on November 22nd at noon. 

 The alkalinity had reached 74 c.c. of centi-normal acid per 

 100 c.c. or more than double the maximum alkalinity in late 

 spring or summer in the sea. 



The hydrogen-ion concentration was also determined in 

 this experiment after about four hours' exposure in November 

 daylight ; it matched at 9-9 c.c. of alkaline phosphate in the 

 phosphatic mixture, the normal sea- water standing at 9-7. 

 Next day at 4 p.m. it was more alkaline than the full strength of 

 the alkaline phosphate, so that the hydrogen-ion concentration 

 was below P H , 10 " 91 . 



Experiment 3. February 13th, 1913. A sample of sea- 

 water was taken at 12-40 p.m. and a small quantity of green 

 seaweed (Ulva enteroides) was placed in it. A titration of the 

 water as then taken gave 1-3 c.c. of centi-normal acid per 

 100 c.c. The bottle containing about 2,000 c.c. of sea-water, 

 and being quite full and stoppered, was exposed to the daylight. 

 February 14th, at 11.30 a.m., the seaweed was floating at the 

 top and showed bubbles of gas entangled. Unstoppered, 

 stirred up, allowed to come to rest, and took 100 c.c. for 

 titration. The sample required 5-9 c.c. of centi-normal acid 

 to neutralise it to phenol-phthalein. A Sorensen determination 

 gives a match at 7-6 Borate to 2-4 HC1, equivalent to P H> 10 ~ 86 . 

 The water removed for the determinations was replaced by 

 fresh sea- water so as to fill the bottle, which was re-stoppered 

 and left exposed to the light. On February 15th at 11.30 a.m. 

 the water was titrated again, the weather having been bright 

 in the interval, but with little direct sunlight. The seaweed 



