﻿424 cox. 



Table III. — .Analyses of clays 1 to 7 recalculated to the anhydrous conditions. 



1___ 



Sample No. 



Silica. 



Alumina. 



Ferric 

 oxide. 



Lime. 



Mag- 

 nesia. 



Alkalies. 





54.2 



45.8 



0.0 



0.0 



0.0 



0.0 



2___ 





52.5 



43.5 



1.2 



0.2 



0.0 



1.2 



3.__ 





50. 5 



48.2 



0.4 



0.5 



0.7 



0.4 



i— 





55.8 



43.2 



0.9 



0.1 



0.2 



0.6 



5_„ 





54.2 



41.3 



0.4 



0.6 



0.4 



2.3 



6__. 





52.0 



42.8 



1.1 



0.8 



0.0 



1.9 







51.6 



43.4 



1.7 



0.5 



0.4 



1.1 



Average . .. '_ 



53.0 



44.0 



0.8 



0.4 



0.2 



1.1 



Some analyses of standard fire clays are given in Table IV and, as 

 will be seen, the analyses of the silicious kaolins numbered 10, 11, 12, 

 19, 20, 21, and .22 compare well with them. 



Table IV.' 3 — Analyses of standard fire clays. 



Source. 



Silica. Alumina. 



Ferric 

 oxide. 



Lime. 



Mag- 



Alkalies. Ignition. 



England (Stourbridge). __ 65.10 22.22 



England (Brierley Hill)_. 51.80 30.40 



Do 69.25 17.90 



United States 74.93 17.19 



Bohemia (Zettlitz) 45.68 38.54 



1.92 



4.14 

 2.97 

 0.79 

 0.90 



0.14 

 0.40 



0.29 

 0.08 



0.18 



0.18 



9.86 



0.50 



1.05 j 



13.11 



1 30 





7.58 



0.46 



1.61 



5.44 



0.38 



0. 66 



13.00 



Analyses of the products of primitive peoples are given by Binns 14 

 from which the following have been selected : 



Table V. — Analyses of the products of primitive peoples. 



Material. Silica. 



Alumina. 



Ferric Ti Mag- 

 oxide. L,lme - nesia. 



Ignition. 



Scandinavian pottery _ 63. 90 



Peruvian potterv j 67.04 



12. 76 

 10.83 

 12.51 



10.24 ' 1.04 0.52 



10.17 , 3.24 0.28 



8.00 3.51 1.83 



11.00 | 

 8.07 

 10.15 



Etruscan potterv __ 1 64.00 





The loss on ignition demonstrates that these products have been fired 

 at a very low temjDerature. The) r are given in order to show the com- 

 parison with the clay materials used by the Igorots. Analyses numbered 

 36 and 37 of Table I are only slightly better than the material the 

 analyses of which are given in the above table. Practically all of the 

 native pottery, cooking pots, "pelones," etc., outside of Manila are made 

 from ordinary brick clay. 



Chemical analyses of clays to be used for commercial purposes, are 

 fundamental and at the outset necessary, for without them the reconstruc- 



13 Cf. Bourry, (55. 



14 Loc. cit., 16. 



