A telescope permanently erected in the open, and exposed to all weathers, must soon lose its smart and bright appearance, but it need lose none of its efficiency, which is of far more importance; for it is intended for service, not for show. The instrument should be kept well painted and oiled. I find vaseline an excellent application for the screws and parts controlling the motions, as it is not congelative like common oils. The observer, before a night’s work and before darkness sets in, will do well to examine his instrument and see that it is in the best condition to facilitate work. Whole tribes of insects take up their habitation in the base or framework, and even in the telescope itself if they can effect a lodgment; and I have sometimes had to sweep away a perfect labyrinth of spiders’ webs from the interior of the main tube. On one occasion I could not see anything through the finder, try how I would. I afterwards discovered that a mason-wasp (_Odynerus murarius_) had adopted the vacuity in front of the eye-lens as a suitable site for her nest; and here she had formed her cells, deposited her eggs, and enclosed the caterpillars necessary for the support of the young when hatched. On another night I came hurriedly to the telescope to observe Jupiter with my single-lens eyepiece, power 252, but could make nothing out of it but a confused glare, subject to sudden extinctions and other extraordinary vagaries. I supposed that the branches of a tree, waving in the wind, must be interposed in the line of sight, but soon saw this could not possibly be the explanation. Looking again into the eyepiece, I caught a momentary glimpse of what I interpreted for the legs of an insect magnified into gigantic proportions and very distinct on the bright background formed by Jupiter much out of focus. On detaching the eyepiece and carrying it indoors to a light, an innocent-looking sample of the common earwig crawled out of it. The gyrations of the insect in its endeavours to find a place of egress from its confinement had clearly caused the effects alluded to. Telescopic observers are thus liable to become microscopic observers before they are conscious of the fact, and perhaps also in opposition to their intention. Other experiences might be narrated, especially as regards nocturnal observing in country or suburban districts, where the “serious student of the skies” may, like myself, find diversion to his protracted vigils by the occasional capture of a too-inquisitive hedgehog or some other marauding quadruped. [Illustration: Fig. 19. The Author’s Telescope: a 10-inch With-Browning Reflector.]