l86 FERTILISERS FROM THE OCEAX. 



Lime also acts on the physical i:)roperties of the soil b>~ 

 altering- stiff and cold clays into loose and warm loams, so that 

 air as well as moisture can freely percolate throug-h the soil. 



As an example of the amount of Lime taken up by plants we- 

 gi\'e the following' : — 



From I acre of land \\'hcat takes 8 lbs. of Lime. 

 From I acre of land Potatoes take 31 lbs. of Lime. 

 From I acre of land Tobacco takes 121 lbs. of Lime. 

 From I acre of land Lucerne takes 1S6.3 lbs. of Lime. 



The subject of using sea-weeds as a manure attracted our spe-- 

 cial attention when we observed the large quantities of sea-weeds 

 thrown up on the coasts of the Colony. We have been informed: 

 that many years ago attempts were made to use these sea-weeds- 

 for the extraction of Iodine, and some Kelp was prepared near 

 Sea Point and sent to tlie Iodine Factories in Glasgow, but it has 

 been given up on account of the great expense. To our knowledge 

 sea-weed is at present not being used in agriculture in South' 

 Africa together with or in place of farmyard manure. Since 

 climatic conditions, the chief of which is the temperature of the 

 sea water, influence to a great extent the growth of sea plants, 

 we have carried out a series of investigations with a view to- 

 ascertaining the compositon of those sea-weeds wliich we obser\ed 

 in largest quantities. 



The sea plants were taken fresh from the sea to the Chemical 

 Laboratory of the South African College and examined imme- 

 diately with reference to the amount of water, which may appear 

 more in our analysis than in those mentioned above in which the 

 material was not so fresh as in our case. Some of the sea-weeds 

 were collected on the Sea Point beach, near the contact zone of 

 the Granite and Slate formations, and others were gathered on the 

 beach at Muizenberg and Kalk Bay. Analyses are given of sea- 

 weeds whose botanical names were kindlv supplied bv Prof. H.. 

 H. W. Pearson, Sc.D., F.L.S. 



Water. Organic Sul)stance. Nitrogen, Asli. 



Sea Grass 77.44 17.64 567 4.S0 



[Enter omorplia In- 

 testinalis) 



Algae 78.04 18.8 35 3.16- 



{Viva Lactiica) 



Fucus Palmatus ... 86.42 8.71 071 4-^7 



(" Sea Bamboo") 



The ashes of these substances contained : — 



Lime. Potash. Phosplioric Oxid^ 



Sea Grass 28.58 16.01 4.48 



Algae (Sea Point) 28.96 11.34 5-57 



Algae I St sample (False 



Bay) ig.87 — 6.9 



Algae (2nd sample (False 



Bay) 21.78 9.5 9.9S 



Fucus (Sea Point) 9.48 30.9 6.59 



Fucus (False Bay) ... ... 7.16 44-3i 3-87 



