1 64 Transactions. — Miscellaneous . 



so more than a thousand years or so ; for, cosmically, the variabiHty of a star 

 is a mere transitory state, as it appears certain that irregularities of surface 

 temperature must ultimately right themselves, although it is singular what 

 a number of phenomena seem to tend in the direction of keeping a star that 

 has been unequally heated by partial impact from having its uniform tem- 

 perature restored. This matter is fully discussed in a paper in preparation 

 on variable stars. Many doubles are coloured. I shall show in the same 

 paper that in all probability the final state of variability in a star is a 

 metallic absorbing atmosphere producing a coloured star ; so that coloured 

 doubles are probably the next youngest pair to the variable binaries. But 

 although the variability of a star is a temporary state, their association with 

 each other is not so. After having once absorbed the nebula their orbit is 

 fixed, nothing but another impact can separate them and that is more 

 likely to make a multiple star of them. 



The final coalescence of the visible Universe will only weld them into 

 the general mass. It is not wonderful therefore that some 10,000 such 

 pairs exist in the Universe. The fact that there are so few speaks to us in 

 powerful language, telling us that the Universe is not so old as we have 

 pictured it to be — that the first day is scarcely over in proportion to the 

 time before its final coalescence. Without doubt this Universe is quite a 

 new member of the Cosmos, of which it is not improbably as a mere drop in 

 an ocean. 



Art. XVI. — On a simple Method of illustrating the Motions of the Earth. 



By Professor A. W. Bickerton. 



[Read before the Philosophical Institute of Canterbury, 2nd September, 1880.] 



Plate IIb. 



This model is one of the extempore pieces of apparatus that I designed for 

 the purpose of illustrating a course of experimental lectures, which were 

 delivered with the special object of showing that many of the most 

 important of physical phenomena might be illustrated by apparatus at 

 a cost not exceeding a few pounds. The model itself cost less than a 

 shilling, and I made it in about half-an-hour. Since it was made I have 

 found it useful to illustrate so large a number of cosmical phenomena that I 

 thought it of sufficient importance to bring before the Institute. A much 

 larger number of phenomena may be illustrated by its means than by the 

 expensive models usually sold for the purpose. Among these are day and 



