During the season of _tempestades_—from the middle of December to the end of March—the weather in the Andes is simply abominable. Mr. Whymper describes everything as “bottled up in mist” after one brief bright hour in the early morning, and complains, writing from Quito, March 18th, 1880,[29] that his exertions had been left unrewarded by a single view from any one of the giant peaks scaled by him. Dr. Copeland adds a lamentable account—doubly lamentable to an astronomer in search of improved definition—of thunderstorms, torrential rains merging into snow or hail, overcast nocturnal skies, and “visible exhalations” from the drenched pampas. At Puno, however, towards the end of March, he succeeded in making some valuable observations, notwithstanding the detention—as contraband of war, apparently—of a large part of his apparatus. Puno is the terminal station on the Andes railway, and is situated at an altitude of 12,540 feet. Here he not only discovered, with a 6-inch achromatic, mounted as need prescribed, several very close stellar pairs, of which Sir John Herschel’s 18 inch speculum had given him no intelligence; but in a few nights’ “sweeping” with a very small Vogel’s spectroscope, he just doubled the known number of a restricted, but particularly interesting, class of stars—if stars indeed they be. For while in the telescope they exhibit the ordinary stellar appearance of lucid points, they disclose, under the compulsion of prismatic analysis, the characteristic marks of a gaseous constitution; that is to say, the principal part of their light is concentrated in a few bright lines. The only valid distinction at present recognisable by us between stars and “nebulæ” is thus, if not wholly abolished, at least rendered of a purely conventional character. We may agree to limit the term “nebulæ” to bodies of a certain chemical constitution; but we cannot limit the doings of Nature, or insist on the maintenance of an arbitrary line of demarcation. From the keen rays of Vega to the undefined lustre of the curdling wisps of cosmical fog clinging round the sword-hilt of Orion, the distance is indeed enormous. But so it is from a horse to an oak tree; yet when we descend to volvoxes and diatoms, it is impossible to pronounce off-hand in which of the two great provinces of the kingdom of life we are treading. It would now seem that the celestial spaces have also their volvoxes and diatoms—“limiting instances,” as Bacon termed such—bodies that share the characters, and hang on the borders of two orders of creation.