NOTES AND ABSTRACTS. 



847 



gain a small supply of vital carbon is enormous. The further stage 

 into nitrate is as follows : — 



Ca(NO,) 2 + 0 2 = Ca(N0 3 ) 2 



Nitrite of lime + Oxygen = Nitrate of lime 



In the absence of chalk, sulphate of ammonia cannot be nitrified. 

 When soil is dust-dry, nitrification ceases. Schloesing found the following 

 results : — 



Percentage of moisture in soils . 9-3 14*6 16-0 20*0 

 Pounds of nitric acid per acre in 



13 months .... 157 172 397 478 



The most favourable temperature for nitrification is 100° F. It is then 

 ten times as active as at 57° F. (Schloesing). 

 The processes are as follows : — 



1. Sulphate of ammonia gives up its acid to the chalk in the soil. 



2. The ammonia is absorbed by the soil. 



3. The ammonia is then converted first into nitrite and then into 

 nitrate by bacteria. — G. H. 



Nitrogen-accumulation by Root-tubercles of Alder and 

 Elaeagfnaceae. By F. Nobbe and L. Hiltner (Nat. Zeit. Land-Forst. 

 ii. pp. 366-369 ; 2 figs. ; 1904).— The beneficial effect of the root- 

 tubercles in rendering atmospheric nitrogen available for these plants is 

 strikingly shown by photographs. Three Alders, four years old, are shown 

 in nitrogen-free water cultures ; two, which have been infected with the 

 tubercle organism, have many tubercles and are four feet high ; the third, 

 which was not infected, is a stunted plant not a foot high. An equal 

 contrast is presented by Elaeagnus angustifolia, four years old, grown in 

 nitrogen-free sand ; the infected plant is four feet high, whereas the un- 

 infected one is barely a foot high, with tiny leaves. Similar results with 

 cultures of Shepherdia canadensis (Elaeagnacece) are also described. 



W. G. S. 



Nitrogen in the Ocean, The Supply of. By K. Brandt (Beih. Bot. 

 Cent. xvi. pp. 383-402). — Criticises Reinke's contribution to this dis- 

 cussion, and shows, by estimating the supply of nitrogen by European 

 rivers, that in 10,000,000 years the sea would contain 300 g. of nitrogen 

 per cubic metre. But in the sea there are denitrifying bacteria which 

 return free nitrogen to the atmosphere. Samples from the Baltic Sea and 

 North Sea (presumably containing such bacteria) were found to denitrify 

 culture solutions. From surface water of the Baltic Sea 100 per cent, of 

 the culture tubes were denitrified, 70 per cent, from water at a depth 

 of 40-73 metres. In the North Sea 37 per cent, surface samples and 

 8 per cent, from 30-230 metres' depth were denitrified. 



The author's suggestion that warmer parts of the sea contain a less 

 percentage of combined nitrogen is confirmed. The author finds the 

 probable average contents of albuminous nitrogen in one cubic metre of 

 sea- water in the Gulf of Kiel to be only 0*03 g., whereas the amount of 

 inorganic nitrogen may reach 0*208 g. But the water of the sea is always 

 in motion, so that alga? will be brought in contact with ample supplied 



