154 Mr. Hellins on the Rectification, &c. 
such series have the advantage, even when the ascending 
series have a good rate of convergency. I trust, however, 
that enough has been done in this Paper to satisfy all candid 
and competent judges of the matter, that the Rectification of 
the Hyperbola by means of two Ellipses is more curious than use- 
ful; that the advantage of computing by descending series, 
is, in many cases, very great ; and that such series will often 
answer the end of a transformation without the trouble of 
making it. 
