Fig. 8. 

 SECTION OF BAMBOO. 



Fig. 9. 

 SINGLE BUILT, 



Fig. 10. 

 DOUBLE BUILT, 



Fig. 11. 



DOUBLE-BUILT STEEL CENTRE 

 BEFORE CEMENTING. 



Fig. 11. 



DOUBLE-BUILT STEEL CENTRE 

 AFTER CEMENTING. 



Fig. 12. 



SINGLE-BUILT OCTAGONAL 

 BEFORE CEMENTING. 



Fig. 12. 



SINGLE-BUILT OCTAGONAL 

 AFTER CEMENTING 



Fig. 13. 



DOUBLE-BUILT STEEL 



CENTRE NONAGONAL BEFORE 



CEMENTING. 



Fig- 13. 



DOUBLE-BUILT STEEL 



CENTRE NONAGONAL AFTER 



CEMENTING. 



SECTIONS OF RODS. 

 PLATE 4. 



