168 Sir Norman Lockyer. 



tion with high powers, these rodlets are seen to multiply by division 

 into equal, or sometimes slightly unequal, halves. By this method 

 the author hopes also to determine whether the change in shape arises 

 from fusion of two or more individuals or by branching. Their multi- 

 plication by division leads to the conclusion that these organisms are 

 members of the Schizomycetes ; whether or not they are true Bacteria 

 must, however, still be undecided, until the final stage in their life 

 history has been fully followed. 



The X, V, or Y-shaped bacteroid, when once formed appears to 

 be incapable of further growth. These organisms are aerobic in 

 character, their power of fixing atmospheric nitrogen is to be 

 tested in connection with their growth on silicic acid gelatine. Com- 

 mercial " Nitragin " consists of minute micrococcus-like bodies, all 

 straight and immobile. They multiply rapidly on gelatine media, and 

 in pea extract become converted into "bacteroids " as well as straight 

 rods. Nitragin does consist of the tubercle organism, and as a result 

 of the inoculation of either seeds or soil with it, tubercle formation 

 takes place. Crossing of kinds supplied for different genera and 

 species is quite successful within the tribe Viciese. In order to test 

 the possibility and conditions of direct infection of the roots, seedling 

 peas, starting both before and after germination, were grown in sterile 

 tubes, by which means the whole plant was kept under control. This 

 method showed that direct infection of quite young radicles is tolerably 

 certain, also of older roots, provided the conditions under w^hich 

 germination occurred are maintained after infection. 



In order to secure infection it is not necessary that the organism 

 should pass through the soil, and the age of the root-hair at the time 

 of infection seems to be without effect upon the result. An accumulation 

 of C0. 2 round the roots is not the cause of failure in direct infection. 



The addition of nitragin to soils rich in nitrates appears to be in- 

 advisable, but a supply of it to soil poor in nitrates results in an 

 increased yield, though better results are obtained if instead of nitragin, 

 nitrates be added to the soil. 



" Preliminary Note on the Spectrum of the Corona." By Sir 

 NORMAN LOCKYER, K.C.B., F.E.S. Eeceived November 11 

 Bead November 24, 1898. 



(PLATE 4.) 



The announcement by Professor Nasini of the possible presence of 

 the characteristic green line of the corona in the spectrum of the gases 

 collected at the solfatara of Pozzuoli,* renders it desirable that I 

 should at once publish some of the results of an investigation relating 

 to the spectrum of the corona with which I have lately been occupied. 

 * 'Nature,' vol. 58, p. 269, July 21, 1898. 



