192 Transactións.— Miscellaneous. 
iron, only on its velocity. So when our dead suns come into impact, the 
temperature will not depend on the size of the spark cut off, only on the 
velocity destroyed. But if the piece cut off be small, it has but little attrac- 
tive power to keep it together, and the particles are so hot—or moving so 
fast—that every single molecule flies completely away and disappears into 
space. Does it not look extremely likely that here we have our temporary 
stars, bursting forth when the collision occurs, and disappearing when its 
particles travel away into space? It certainly appears very likely. 
But what about the two large pieces (the two wounded stars) ; a slice 
has been cut off each, and the hotter interior exposed; friction has also 
developed heat, and so when they become round again they will be hotter 
on one side than on the other. As they revolve they must almost certainly 
form a variable star, and the struggle of the two rotations will make this 
variation pass through long cycles, just as a spinning top oscillates if it has 
a kick. But as it would seem that two variable stars must be often pro- 
dueed together, the lists were searched to see if any pairs could be found, 
and a chart has been made from Chambers’ list, and it shows sixteen well- 
marked pairs, or thirty-two connected stars out of one hundred and twenty. 
Unless we suppose this spotted condition to be a disease and catching, it is 
difficult, except on this view, to account for the pairs. Not only do we 
thus find these pairs existing, but some variable stars are close to the places 
where old temporary stars formerly existed, and also variable stars have 
become ordinary stars, as we should expect them to do when the tem- 
perature became uniform; and doubtless when the whole are carefully 
matched, many will be found to be gradually approaching the state of uni- 
formity exhibited by ordinary stars. But it is not necessary to suppose 
thate th piece struck off each should always be such an excessively small 
ratio as to be projected into space, although the temperature produced by 
the collision will be almost always high enough to make gas of the coalesced 
part. This part may have mass enough to remain a permanent nebula. 
In this case reasons have been urged that render it probable that at first 
this gas would tend to take a spindle shape. Afterwards many possibilities 
present themselves according to the varying circumstances of the collision, 
for it is perfectly evident that these may be very numerous indeed. As the 
bodies may vary from cold dense solid bodies to rare masses of hot diffused 
gas, they may originally be moving very fast or very slowly ; they may have 
been spinning with great velocity or hardly rotating at all; they may be 
nearly the same size, or a very unequal pair ; and it does not need a Newton 
to see that any of these states will influence the result attained at collision 
and afterwards. The only effects which appear absolutely certain to follow 
partial impact are that rotation must ensue, that the matter will tend to 
