Page:The American Cyclopædia (1879) Volume VI.djvu/68

 60 DEW , ami was present at the battle of Water- H afterward en-aged in mercantile pur-
 * .l in lsi;i made his debut on tlie stage

at Itrnn-wiek. In l*Jo he married the cele- -inircr Wilhelmine Schroder, from whom he was divorced in 1828. (See SCHRODER.) He acted in all parts of Germany, but was for established at Hanover. He was lebratcd for his spirited personation of leading parts in genteel comedy. HI. Philipp Kdnard, brother of the preceding, born in Ber- lin. An-. 1 1, 1801. He commenced his artistic as a baritone singer, but afterward ap- almost exclusively in the spoken drama. Ho was a careful and cultivated actor, a success- ful writer (f dramas, and an authority on all that pertains to the profession. His chief works hav- been eolK-eted under the title of Drama- tuche und dramaturgische Schriften (8 vols., l.eip-ic, 1846-'61), including several plays, mis- cellaneous publications relating to the stage, and a history of the drama in Germany. l Gista? Emil, brother of the preceding, born in IJerlin, Sept. 4, 1803, died in Dresden, Aug. 7, 1872. Like his two brothers and his uncle, he was intended for the mercantile profession, but in 1821 went upon the stage, where he soon gaiiu-d distinction, assuming with success many of the parts, both in tragedy and comedy, with which his uncle Ludwig's name is identified. His wife, Dorothea Bohler, from whom he was divorced in 1842, was an excellent comic ac- tress, and ably seconded her husband for many years. On Nov. 10, 1857, the 98th anniver- sary of Schiller's birthday, three members of the I 'evrient family, Gustav Emil, Karl August, and Karl's son, appeared together at Hanover, in the play of " Don Carlos." Gustav retired from the stage in 1867, having accumulated a large fortune ; after which he wrote a history of the German stage, nnd an autobiography which was to be published after his death. DEW, the humidity of the air, deposited on cool surfaces with which it comes in contact. It is commonly formed at night upon the leaves of grass and fives and other objects, especially when the sky is clear so as to permit sufficient radiation of heat from them to cool their sur- Mid c.nse<|iiently the layer of air next thi in. below the point of saturation, or dew point. The inoi-ture which collects upon the i cold body, as a pitcher of ice -tandinir in a warm room, and that which collects on a window pane when it is breathed upon, are strictly examples of the which form on windows and stone flagging of courtyards ; ,nd walks. J n the latter case the solid surface- have a temperature below the 1 of water, and therefore the par- of moisture assume a crystalline form in-' from 'their invisible condition. The figures thus formed owe their variety to the varying degrees of tem- pentture and moisture, and rapidity of deposi- i.'l also to the nature of the surface of the body and its thermal inequalities, which necessarily exist in curves. The different causes of the formation of dew were never clearly understood until the early part of the present century. The ancients connected its appear- ance with the intervention of supernatural powers. As it mysteriously appeared when the air was clear and apparently dry, and gathered upon the herbage in sparkling beads, while it avoided the barren and rocky surfaces, they might well look upon it as a special bless- ing, possessed of wonderful virtues. Hence it came to be prescribed for restoring the charms of youth, and to be used by the alchemists as a solvent of subtle and mysterious powers. The ancients generally entertained the idea that the moon and stars not only poured down cold upon the earth, but also, in some myste- rious way, distilled dew. Aristotle was the first to approach a rational explanation, al- ' though, from a want of knowledge only ob- tained by the use of modern philosophical in- struments, his explanations contained errors. He believed aqueous vapor to be a mixture of water and heat ; and as it rarely appeared on mountain heights, he supposed it was abandoned by the heat, and left to precipitate itself upon the earth. He rejected the idea of lunar or astral influence, and maintained that the sun was the prime cause, " since his heat raises the vapor from which the dew is formed as soon as that heat is no longer present to sustain the vapor." In the middle ages philosophers re- vived the notion that the moon and stars were the cause of dew. Battista Porta showed the erroneousness of these views by instancing sev- eral facts, but he discarded the correct part of Aristotle's theory, that dew was condensed vapor separated from the atmosphere, and ad- vanced the idea that it was condensed air it- self. Musschenbroek observed that it was de- posited more readily on some substances than on others, and therefore correctly inferred that the object itself had an important influence in its formation. This led to a reconsideration of Aristotle's theory, and its adoption, with the modification that instead of its being dis- charged from the mass of the air it was only removed from the stratum in contact with the object upon which it was deposited. The ex- periment of placing a cold body in a warm moist atmosphere proved the correctness of this theory. But it was not till a series of ex- periments were made by Dr. William Charles Wells (a London physician, though a native of Charleston, S. C.), and published in August, 1814, that a comprehensive theory of the for- mation of dew was publicly promulgated. His experiments were made in a garden in Surrey, near Blackfriars bridge, and will for ever re- main as admirable examples of ingenious philo- sophical investigation. He exposed little pieces of dry wool of equal weights and sizes during the night, their increased weight in the morn- ing showing the amount of dew which had been deposited. The quantity thus collected
 * "ii of dew, and also the frosted figures