434 



APPENDIX 



ON DRAWING THE 



intersect the primary planes P' and P, parallel to their 

 oblique diagonals. If therefore two planes corres- 

 ponding to o and o', No. 4, be conceived to pass 

 through the oblique diagonals of No. 3, and to be 

 produced until they cut the edges g g f and g g", it 

 is obvious that they would cut those edges at the 

 points k and &', and the point i would then be common 

 to the three planes. 



Assuming any point in the front vertical edge of 

 No. 4 3 we may draw those lines of plane g which 

 intersect o and o', then those which intersect p and 

 p', and P and P' 5 and finally the intersection with m, 

 to complete the figure. 



Fig. 389. 



