Page:Proceedings of the Royal Society of London Vol 1.djvu/27

Rh In the next sections he shows that the penetrating and magnifying powers, so far from assisting each other, will often prove reciprocally detrimental, which he thinks may be explained by admitting that while the light collected is employed in magnifying an object, it cannot be exerted in giving penetrating power; to which perhaps ought to be added the detrimental effect of the magnifying power on the heterogeneous ingredients ﬂoating in the atmosphere. Whatever be the cause, the fact is proved by various observations.

Lastly, he shows that as we must not limit our vision within the sphere of the single stars, we must call the united lustre of the sidereal system to our aid in stretching forward into space. Supposing one of these clusters of 5000 stars to be at one of those immense distances to which only a 40-feet reﬂector can reach, he calculates that this distance will exceed at least 300,000 times that of the most remote ﬁxed star visible to the naked eye. He concludes with a rough calculation how much time it would take to sweep the heavens with a penetrating power of such an immense extent; and ﬁnds that in this climate, with his 40-feet reﬂector, with a magnifying power of 1000, this operation for the whole sphere would take no less than 811 years.

This paper relates to an improved solution of a problem by which swiftly converging series are obtained, which are useful in computing the mutual perturbations of the planets; and contains some further remarks and improved formuliefDr computing the coefficients, by which the arithmetical work is considerably shortened and facilitated.

This peculiarity was ﬁrst observed in the axillary arteries and in the iliacs of the Lemur tardigradus, which at their entrance into the upper and lower limbs were found to be suddenly divided into a considerable number of equal-sized cylinders, which occasionally anastomosed with each other, and were regularly distributed on the muscles; whilst the arteries proceeding to the other parts of the body divided in the usual arborescent form.

Upon prosecuting this inquiry, it was found that the Bradypus