386 K. J. ALI-KN AND K. W. NELSON. 



Next best in series to a ; lasted longer than d, and 

 had better colour. 



To generalise, no improved culture is obtained with solution 

 A alone, but a fair, though not very lasting, growth can result 

 from using solution B only. 



The action of solution B is to some extent obscured by the 

 fact that, when this solution is added to the alkaline sea- 

 water, a precipitate is formed. This precipitate is at first 

 white, but, on heating or standing for some time, it becomes 

 greenish-yellow. We are indebted to Mr. D. J. Matthews for 

 the following analyses. 



Ten litres of normal Miquel sea-water were prepared, and 

 the precipitate was collected on a filter-paper, washed, and 

 <lried at 100° C. 



Weight of dry precipitate from 10 litres = 0*2949 grm. 



100-16 

 Or the precipitate from 1 litre of normal Miquel sea-water 

 contains — 



PoO.- -00777 grm. 



FeA ...... -01218 „ 



Cab -00225 „ 



An analysis of 1 c.c. Miquel solution B, the amount added 

 to 1 litre Miquel sea-water, gave — 



P0O3 ...... -00825 „ 



Fe.O,, ....;. -0105 „ 



CaO -0145 „ 



Comparing these figures it seems probable that, when added 

 to sea-water, all the iron in solution B is precipitated, and 

 a certain amount also of the phosphate and calcium. The 



