Drawing of Curves hy their Curvature 



75 



Elements. 



In Arc. 



In Sun. 



Kind 



of 

 Stand- 

 ard. 



Weight. 



Wave- 

 length 

 in Arc. 



Wave- 

 length 

 in Sun. 



Inten- 

 sity. 



Appear- 

 ance. 



Inten- 

 sity. 



Appear- 

 ance. 



In 

 Arc. 



In 



Sun. 



? 







v • 



2 



7 

 6 

 6 

 6 

 6 

 6 

 3 



io 



12 

 12 

 14 

 14 

 14 

 14 



8 



8 



7. 



7 



7 



4 





0' 





 O 

 

 

 

 O 





3 

 2 

 2 

 3 

 2 

 3 

 3 

 1 

 4 

 5 

 4 

 4 

 3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 

 1 

 1 





7331-206 

 7389-696 

 7409-554 

 7446-038 

 7462-609 

 7495-351 

 7511-286 

 7545-921 

 7594-059 

 7621-277 

 7623-526 

 7624-853 

 7627-232 

 7628-585 

 7659-658 

 7660-778 

 7665-265 

 7666-239 

 7670-993 

 7671-994 

 7699-374 

 7714-686 



9 



? 



? 



9 



? 



9 



? 



A(0)* 



A(0)t 



f A(0) . 



1 1 A(0) . 



2 JA(0). 

 J lA(0). 

 7 /A(0). 

 7 lA(0). 



»{*8: 



? 



? 













* Beginning of the head of A. Outside edge, 

 t Single line at the beginning of the tail of A. 



Y. On the Drawing of Curves hy their Curvature, 

 By C. V. Boys, A.R.S.M,, F.B.S.* 



[Plate I.] 



WHILE giving a course of lectures to working men 

 on Capillarity at the E. School of Mines in 1891, 

 I wished to explain the principles upon which the form of 

 a water-drop depends, and to show that an accurate scale- 

 drawing could actually he produced by following Lord 

 Kelvin's rule (Proc. K. Inst. Jan. 29, 1886) ; but found that 

 the procedure was so cumbersome as to be in no way adapted 

 to popular exposition. In my attempt to simplify the opera- 

 tion I devised a method of carrying it out which has the 

 double advantage that any of these capillary surfaces of 

 revolution can be drawn with a facility which cannot be 

 approached by following Lord Kelvin's instructions explicitly, 

 while the accuracy of any curve thus determined is so great 



* Communicated by the Physical Society : read May 12, 1893. 



