288 
Proceedings of Royal Society of EdinhurgJi. 
noticeable effect is to slightly alter the values of p for which pjq 
vanishes. We therefore have, to a quite sufficient approximation, 
P 
= 2*1712 
where the literal factors have been retained in the more important 
p 
portion. The value of ^ in terms of p is thus seen to be a 
numerical multiple of the ratio of the corresponding ordinates of 
two equal and similarly situated parabolas, whose vertices do not 
