ON PRIMITIVE MAN : 1. HIS TIMES AND HIS COMPANIONS. 267 



under certain conditions tend to undergo molecular chancre at tho 

 surface (to a depth sometimes of a quarter of an inch) inducing: a 

 kind of porcellanic texture, which, with inequalit}- of expansion 

 and contraction between it and the flinty interior for changes of 

 temperature, is very likely to split off in places without the appli- 

 cation of a rrjechanical blow. Lastly, the consideial:)le variety of 

 intimate molecular strncture which flints display, and the varying 

 proportions found in tliem of crystalline and colloid silica, not to 

 mention the presence at times of mineral impurities in the flint 

 itself, show how under the action of solvents (especially in old 

 volcanic regions) conditions favourable to fracture may be 

 induced. 



I have dealt with the petrology of flints more fully in my little 

 work on Metamorphism of Rocks (Longmans, 1889), and need 

 not therefore treat the matter more at length here. Enough, I 

 venture to think, has been said, to show that Mr. Mello's difficulty 

 is more apparent than real ; since it is at least as easy to account 

 for the fact observed by M. Rames by a process of natural selection 

 through the operation of known laws of nature among the varieties 

 of flint, as by an " intentional selection made by an intelligent 

 being." 



Captain H. G. Lyons, R.E., F.G.S., writes : — 



In this very interesting paper on Primitive Man the author 

 includes Egypt as furnishing implements of the S. Acheuleen type, 

 and no doubt rightly as in the instances given by General Pitt 

 Rivers, Professor Zittel, Dr. Schweinfurth, etc., but at the same 

 time there is a large quantity of flint implements which are 

 cei-tainly of a much later age. Snrgeon-Major Archer collected a 

 number of flakes and other implements from Wady Haifa near the 

 Second Cataract, and these cannot, I think, belong to any very 

 remote date. From the same district I have collected a consider- 

 able number of flakes, scrapers, portions of a dagger-shaped imple- 

 ment worked on both sides, diorite hatchets, etc., but all are from 

 ancient Egyptian sites of temples or of their frontier fortresses. A 

 single instance of a roughly chipped arrow-head occurred where no 

 such ancient settlement could be traced, but not under conditions 

 justifying the conclusion that it belonged to the " Stone age." 

 Here certainly the amount of finish is no guide, and the roughest 

 flakes and worked scrapers occur side by side with polished diorite 

 hatchets. 



Wddy Haifa. 



