00 





Ri h Portland 



1 Mixture made al Folkestone t chalk and gault clay 



1 >ean limestone and clay 

 Mixture from Barrow lias quarries 

 All dried at 10U C, but 2 and 3 have perhaps also lost - 

 11 <>. 



1 2 



- 1 2.5 5. 



- i 11. 1 .61 



1 1. 2 



Alumina .45 



tr 



Ca< 0} 74.18 



MgCO 1. 



18 



9 



31 



Kfi. . 



Na I 

 II J I . 





75.80 

 1.5 



.10 

 .88 



.39 

 .61 



3 

 2. 

 11.41 

 2. 



4.8 



74.09 

 2 . *, l 



.21 



.46 

 .43 



A clay or Medway mud from Gillingham is as follows: 



1.727 

 2.057 



.::■> 



3.384 



BiO, 33.413 



Al and Fe 1 . 



25.249 



AM' 14.244 



' 0.744 



CaO 81 



MgO 



K I I 



Na,0 



[1,0 



Pyrite 214 . 



Sand 



\. Hyd. 



silicates 



Tho clay used fV.r or-mont should not contain an pxcp^ of sand 



or iron, (lays low in iron are usually of a gray or blue c<»l«»r 



light yellow on weathering. The clay should ho fairly sili- 



and tho mr.rr- amorphous silica present the better. Mi- 



gi - the following typical exampli 



1 H. her m"<Tto] u. Pnrtl.nn<]-rpmontP, p. 00. 



