C A U 



with the line of their intersection vertical, the water will ascend between 

 them and form an hyperbola. 



4. To find the diameter of a eapillar y tube, put into the tube some mer- 

 cury, whose weight in grains w, and let it occupy a length of the tube 

 I, then 



Diameter v j- X 09123 in inches. 

 CATENARY Equations, $c. to. 



Let A', y, and z be the abscissa, ordinate, awl curve, then the F.fiiiu- 

 tions to the curve are, 



ad x 



y = a x h. I ' 



Subtangent *^. 

 Area y V a* -f. # 2 a r. 



Surface = 2xyz + az-. a Va 2 -f z* 



Content of solid = * (2 a* + */ 2 x a + jr 2xy*-f- */ 

 CAUSTICS. f Coddington.) 

 1. Caustics produced by reflection. 



1. Given a point, from which a thin pencil of rays proceeding fall on 

 i curved reflector, to determine their intersections after reflection. 



Let the incident ray u 



the reflected ray v 



/of incidence ~ <p 



Perpendicular on the tangent p 



Principal focal distance of reflector ,,. f 

 46 



