" I s HE substance of the following Paper was read to the Rochdale 



Literary and Scientific Society, in February, 1881. It has 



been carefully re-written, and is now published because of the growing 



interest that most persons feel in the matter with which it deals. 



The principal authorities quoted are Ramsay, Dawkins, Croll, 



Haughton, Evans, Lubbock, Wilson and Tylor. 



H. C. M. 



