on the Light of the Cassegrainian Telescope, &c, 247 
of error; from these objections, however, I must observe, 
the experiments made within both foci are in a great measure 
exempt. 
With respect to the experiments detailed in the preceding 
part of this paper, it may be remarked in their favour, that 
the observations were made by eight different persons at 
various times, and by different methods, and that the near 
coincidence of the results with each other, and with the num- 
bers deduced from the experiments made with the Cassegrai- 
nian and Gregorian telescopes, seem to warrant the conclusion 
that a mean of the whole may be considered as a tolerable 
approximation to the truth. 
London, April 20, 1814. 
