EXPLANATION OF PLATES. 



767 



Fig. 3. Is the form of the Stile for East and West Dials. 



Fig. 4. Represents a Polar Dial. 



Fig. 6. Is a Diagram for explaining Vertical Declining 

 Dials. 



Fig. 6. Represents a Vertical South Dial declining 

 to the West. 



Fig. 7. Represents a Vertical South Dial declining 

 to the East. 



Fig. 8. Is a Diagram shewing how to construct a De- 

 clining Dial, by considering it as a Horizontal 

 Dial for some other place. 



Fig. 9. Is a Diagram shewing how to find the Decli- 

 nation of a plane. 



Fig. 10, II. Are Diagrams explaining the theory of 

 Inclining Dials. 



Fig. 12. Represents an Inclining Dial. 



Fig. 13, 14. Are Diagrams shewing how to find the 

 path described on a plane by the extremity of 

 a Shadow. 



Fig. 15. Is a Diagram explaining the Retrogradation 

 of the Shadow on particular Dials. 



Fig. 16. Explains the theory of Dials with Variable 

 Centres. 



Fig. 17. Represents a Dial with a Variable Centre. 



PLATE CCXXX. 



Fig. 

 Fig, 



Fig. 

 Fig. 



Fig. 

 Fig. 



Fig- 

 Fig. 



Fig. 



Fi , 



Fig. 



1. Shews the geometrical construction of an 

 Analemmatic or Azimuth Dial. 



2. Represents a Dial which sets itself, being 

 composed of an Analemmatic and a Horizontal 

 Dial. 



3. Represents Lambert's Dial. 



4. Shews how to construct a Portable Dial on 

 a Card. 



5. Represents a Portable Dial on a Card. 



6. Represents a Dial on the surface of a Cylin- 

 der. 



7. Shews how to construct the preceding Dial. 



8. 9, 10. Shew the construction of a Ring 

 Dial. 



11, 12. Represent an Universal Dial on a Cross* 



and the method of constructing it. 

 13. 14. Represent Ferguson's Universal Dial 



which shews the hour by the Terrestrial Globe 



and by several Gnomons at the same time. 

 15. Represents a Vertical South Dial, with the 



Babylonian Hours. 



END OF VOLUME SEVENTH. 



Edinburgh : 



Printed by A. Balfour. 



