KAIMONDI. 672 RAIN. for ransom by the Spaniards at an exorbitant sum. He returned to Bologna, -where he died not later than 1534. The chief jHipils of, his school at Rome were Agostino Veneziano and Marco Dente of Ravenna. Consult _Delaborde, ilarc- Antoinc Ruiinondi (Paris, 1887). BAIMUND, ri'munt, Ferdixaxd (1790-1830). An Austrian aetor and playwright, born in Vienna. After playing on provincial stages in Hungary, he secured an engagement in Vienna at the Josephstiidter Theatre in 1813, and in 1817 at the Leopoldstiidter Theatre, where he soon became the most popular exponent of local comedy, and which he managed as director in 1828-30. In the meanwhile he had come before the public as a popular dramatist with Der Baromrtrrmachcr auf der Zauhcrinsel (1823); Dcr Dkunaiit des Oeislerkiinigs (1824); Der Bauer als Alilliomir (1826) : Alpcnkonig und Menschenfeind (1828); and others which, after severing his connection with the Leopoldstiidter Theatre, he mounted on the stages of ilunich, Hamburg, and Berlin, appearing himself in them in a starring capacity. His last and best play ■was Drr Tcrsclurcnder (1833), which is still jiopular on the German stage. In a fit of hypochondria Rainiund attempted his life with a' pistol and died within a week on his little estate of Gutenstein. He was a genuine poet in the popular vein, who dwelt with affectionate sympathy upon the life of the ])eople, and weaved its joys "and sorrows into the fabric of fantastic dramas of peculiar charm. Their pathos and humor are alike telling. His life was made the subject of a novel by Otto Horn (Biiuerle) and of several dramatic productions. By the Raimund Dramatic Club, founded in Vienna in 1800, the Raimund Theatre was established there in 1893. RAIMUND, GoLO. The pseudonym of the German novelist Bertha Frederich (q.v.). RAIN (AS. regn, ren, Goth, rign, OHG. rcgan. Ger. Regen, rain; connected with Lat. rigare, Gk. jSp^x"". l>rechein, to wet). Drops of water formed in the atmosphere by the condensa- tion of its aqueous vapor and falling rapidly by virtue of their weight: the very small drops that fall slowly are spoken of as mist, cloud, or fog. The largest drops of rain that have been" meas- ured are as much as 0.25 to 0.30 inch in diameter and fall at the rate of from 15 to 25 feet per second. The smallest drops that are likely to be spoken of as rain are about one-twentieth of an inch in diameter and fall at the rate of about five feet per second. As rain water is condensed vapor that had previously been evaporated from distant water surfaces, there- fore, in accordance with the laws of evaporation, it would be chemically pure water were it not for a small percentage of foreign substance which it gathers to itself from the atmosphere. Rain water washes down out of the air dust, soot, pollen, spores of fungi, and many other solid substances. Ordinary rain water contains an appreciable percentajje of dissolved oxygen, nitro- gen, ammonia, and carbonic acid gas, and in spe- cial cases it is found to contain nitric acid, sulphuric acid, and other components of the impiire air of cities. The acid and alkaline im- purities generally increase the power of the rain water to dissolve the mineral constituents of the earth's crust; the gases make it possible for plants and animals to live in rivers and ponds, which would be impossible if the water were chemically pure. Rain water only becomes whole- some potable water for man's use after it has been thoroughly filtered through the earth, whence it issues as springs of pure water. Up to the middle of the nineteenth century rain was supposed to be naturally formed by the mixture of cold and warm masses of moist air, but the publication of Espy's Philosophy of Htorms (Boston, 1842), and his life-long conten- tion that cloud and rain are not due to cooling by mixture or by radiation, liut arc a consequence of the cooling of the atmospliere by virtue of the work done in expansion, supported as he was by Professor Joseph Henry, Sir William Thom- son (Lord Kelvin), and other physicists, finally led meteorologists to studj- the great thermodynamic problems of the atmos- phere. When air is forcibly compressed, the work done by compression is repre- sented by the increase in temperature of the confined air; rice versa when the air expands by diminution of pressure, the work done in expansion is represented by the heat abstracted from the expanding air, which therefore ex- periences a corresponding cooling. The laws of convective equilibrium governing the temperature and the volume of a unit mass of rising air were first expressed in the exact language of mathe- matical physics by Sir William Thomson in 1861. Graphic methods of treating the complex meteorological proljlems were de- vised by Hertz in 1884, and improved by Von Bezold " in 1888 and XeuhofT in 1900." The analytical treatment of the subject is given by F. H. Bigelow with convenient tables in his report of 1900 On the International Observat ions of Clouds. When warm moist air ascends from near the earth's surface it cools by expansion ; if no heat is added or subtracted, it is said to cool adiabatically, and does so at the rate of about one degree Centigrade per 99 meters of ascent, or one degree Fahrenheit for 185 feet, until it reaches an altitude at which its tem- ])erature is the same as the temperature of the dew point of the original air. At and aliove this elevation cloud is formed as the air ascends. If the rise continues until the air has cooled to the temperature of freezing point of water, then the watery cloud jiarticles begin to change to ice, giving out a little of their latent lie.it as they do so. When in the course of its further ascent all the cloud particles have become ice, then any additional rise will be accompanied by the formation of snow crystals. This latter condition would continue to exist throughout the further ascent of the air were it not that in these higher regions the formation of snow is very slight. If the sim is shining upon the clouds, the process ceases to be adiabatic, and the particles of water or ice may be immediately evaporated back into vapor. Owing to the resist- ance of the air. the cloud particles fall very slowly to the ground, or may, in fact, be upheld in- definitely by a gentle ascending current. But if numerous small particles combine together into drops of water, the latter may fall rapidly to the ground as rain. The above paragraph cor- rectly explains tlie fonuation of cloud by cooling due to expansion, but nothing is as yet known satisfactorily as to the process by which large raindrops are formed from the minute cloud particles. Among the several plausible hypotheses are the following: (a) That the cloud particles are
