THE GEOLOGIST. 



who would look at those articles. 

 But the same certainty of their human 

 origin is not to the inexperienced so 

 evident when these flake instruments 

 are broken, as they are extremely 

 likely to be. They are then, appa- 

 rently, only so many ordinary chips; 

 but the impress of design clings to 

 the smallest fragment, and from a 

 chip a quarter of an inch in length 

 one could almost speak with cer- 

 tainty. The method of manufacture 

 of obsidian instruments by the ^ 

 Peruvians and South Sea Islanders <§' 

 gives the easiest possible solution 

 of the process, which is compara- ^ 

 tively easy of accomplishment in 

 that mineral, but rather more i, 

 difficult in flint, although the method § 

 is nevertheless the same in both. Ef- 

 We will suppose, however, that the 31 

 savage has got a block of obsidian % 

 — he first trims it to an angular form, ^ 

 six-sided, eight, ten, or any number gf 

 of sides will do — thus, (fig. 40.) He & 

 then by a series of smart blows struck p 

 at each of the corners, a, a, a, (fig. 41,) o 

 splits off each of the angles, as long J- 

 narrow flakes, broad at the top, and ij 

 tapering away more or less to a point, B 

 and having a sharp cutting edge on g! 

 either side, (as marked out by the 3 

 dotted lines,) and characterised by § 

 a ridge formed by the angle of the % 



back being flat or very slightly - p 

 convex. © 

 From the chipping off of the angles ^ 

 the block will assume the shape g 

 now indicated, (fig. 42,) its second & 

 stage, being still an octagon with o 

 the angles or corners all truncated, | 

 and presenting a flat ribbon-like band P 

 which will characterize the second 

 set of flake-knives formed by the 

 chipping of these truncated angles. 

 It will be seen that the second 

 operation reduces the block to its 

 primit ive form with sharp corners or 

 angles; a third operation will restore 

 again the truncated stage, and 

 alternately each successive flaking 

 will bring about the alternate con- 

 ditions, so that all the flake knives 

 obtained by the process will show 



block. 



down the front ; the |. 



