FORMATION OF METEORITES 387 



one whose real frequency is quite unknown, since extinct suns 

 are beyond the reach of observation. If the active lives of suns 

 are no greater than the periods deduced from computations 

 founded on the Helmholtz theory of solar heat, extinct suns 

 should either be numerous, or the whole previous history of the 

 stellar system must have been short ; or else, as a tertmm quid, 

 some effective means of regeneration must be assumed. 



In the more typical case of two live suns coming into 

 such close relations, its seems probable that mutual dispersion 

 might follow without serious collision, since the analysis of the 

 phenomena seems to show that the mutual elongations of the 

 live suns would develop on essentially parallel lines whose con- 

 stant shiftings would be mutually consonant, as illustrated in Fig. 

 2. If no serious contacts were developed, the two resulting 

 spirals would separate and pursue the paths normal to their 

 parent stars, with such modifications as may have resulted 

 from the loss of energy involved in giving rotation to the 

 nebulae. 



If, however, the periastron approach is so close that partial 

 collision ensues, the analysis seems to indicate that the elongated 

 bodies which would be developed previous to contact would not 

 collide end to end centrally, but by a lateral shear, as illustrated 

 in Fig. 3. In this case the arrested momentum combines with 

 mutual attraction to give a rotatory movement of the highest 

 order, and the heat and the resilience from impact must combine 

 to intensify the dispersive competency. The arrest of momentum 

 may be presumed to go so far in some cases as to cause the two 

 bodies to unite to form a single spiral nebula of the largest and 

 most dispersed order, such perhaps as the well-known great 

 spiral nebulae; or the arrest may be partial, and certain parts of 

 one or the other, or both, of the masses may escape. In No. 

 I, Plate I, we seem to have a possible example of this, in which 

 the escaping, or partially escaping, mass ^ is still associated with 

 the longest arm of the spiral. 



'This is assumed to have been a dead sun because of the limited evidence of 

 explosive action. 



