MILDEW. 483 MILELLl. their attachment to the leaves, and in the spring ])iesent English mile by lioni 142 to 144 yards, they develop a new generation of thin-walleil Un the Continent of KuroiJe previous to the gen- spores lor the spread of the disease. There are iTal adoption of the nietrie system, the length about 150 described species of powdery mil- of the modern mile hi ditlercnt countries exhibit- dews, and there are few of our plants that arc cd a remarkable diversity not satisfactorily ac- not subject to attack from some of them. Among counted for. Before the time of Elizabeth scien- the common ones injurious to economic plants liiic writers made use of a mile of 5000 English are the apple, pear, and cherry mildew (I'ud- feet, from the notion that this was the Roman tisiilicFra oj-ymntha;) , rose mildew (S/jhwrutlwcii niile, forgetting the dilVcrcnce in value between IKiiiiiosn) . hop mildew (Sphwrotheca custagnvi), the English and Roman foot. The present Eng- grape mildew {Uncinula spiralis), mildew of Ijsh statute mile was incidentally defined by an wheal and other grasses {Eri/siphe graminis), act passed in the thirty fifth year of the reign gcjoscbcrry mildew {Sphwroiheca uiors-ia-a;) , eu- of Elizabeth to be "8 furlongs of 40 perches of cumber mildew {Erysiphe cichoraccaruin) , which 10% feet each" — i.e. 1700 yards of 3 feet each — also attacks verbenas, sunflowers, asters, and and it has since retained this value. The gco- other plants, pea mildew {Erysiphe niartii) , etc. graphic, nautical, or sea mile is variously de- Downy mildews are internal parasites whi<-h grow fined as (a) the length of a minute of latitude through the tissues of the plants tlial bear them, at any point, (b) the mean length of a minute and only appearing outside to shed their micro- of latitude (0082.00 feet), and (c) the length scopie spores. The branches of the fungus bearing of a minute of longitude on the equator (6087.15 thoe spores are often .so abundant as to give a feet). The United States Coast Survey hag peculiar downy or frosty appearance to the leaf adopted as the standard geographic mile the or other part of the plant infested. The spores length of a minute of latitude of a sphere having (conidia) are one-celled, thin-walled, and are the same surface as the earth. This gives a readily blown about by the wind. Falling upon length of 6080.27 feet. The British Admiralty a new leaf or plant, if the moisture conditions niile is 6080 feet. As the United States statute are favorable, they quickly germinate and set mile is 5280 feet, a nautical mile is 1.15155 up a new infection. In this way they spread statute miles, or 1853.24 meters. For ordinary with great rapidity, and often produce epidemic purposes of navigation the naiitical mile is as- outbreaks of disease. The resting spores are sumed to be equal to a minute of latitude in the formed within the tissues of the host, and are region navigated, the error being inappreciable tluis carried over from season to season. They in the calculations. are liberated by the decay of the tissues sur- The following table gives the length, in English rounding them, and from these a new generation statute miles, of the various miles that have been is derived. Among the downy mildews are some or are commonly used: of the most .serious plant parasites. The more Euk. miles common ones are the potato rot or mildew {Phtj- Enellsh t'eographical mile =1.153 , ., . , . , ^ ji 1 -11 German geoi^raphical mile =4.611 tophlhora mfestans) , the grape downy mildew Tusuan mile = 1.027 (I'hisDwpara viticola). lima-bean mildew {Phy- Ancient Scotch mile =1.127 tophthora phaseoii). lettuce mildew {Bremia „erman^*t^ne;;:::::::::::::;:::::::;zz:::;3^ =3:89? lavtucw), onion mildew {Peronospora schleideni- Prussian mile =4.680 unit), cucumber and melon downv mildew {Plas- Danish mile =4.684 mopnra ciihriisis). downy mildew of raiiishes and s^^"^ '^"^■:::::z:z:zzzz::::z'z::"z =5:201 other oruciferous plants {Cystopiis cintdiilus) , Oernian long miie!!..."!..."!.'.."!..'.'... =5.753 etc. ^fost of these mildews are more fully de- Hanoverian mile = 6.568 scribed under the diseases of their respective fi^i^^^z::::::::""::::::::::::::::::z^^^^^ Zo.^ host plants. The problem of combating them and 29 kii! = 18 English s'tetutem^^^ has been a subject of much experimentation in ^^^ Weights .^nd Measure.s and Metric America and in Europe. It has been tound that tjysTFM nianv of the powder' mildews can ba hehl in check and'often serious loss prevented by dusting the MILEAGE. Compensation reckoned at so plants with sulphur, or. if in a house or frame much per mile in lieu of traveling expenses usual- where it can be done, exposing them for a few mo- '.v allowed i)uhlie officers, who arc compelled to ments to the fumes of boiling, but not burning, journey to the seat of government in order to sulphur. Spraying thoroughly and repentedlv with discharge their official duties. It is usually Bordeaux mixture, ammonia'cal copjier carbonate reckoned according to the shortest route by which solution, or other standard fungicide (q.v.) will the officer is able to travel, although there are prevent the serious attack of both classes of sometimes cases of constructive mileage where mildews. Success in these preventive treatments compensation is allowed for distances which are depends upon thoroughness. See Disea.ses OF nnt actually traveled. The mileage .system of Plants- Fingi Economic compensation is in very general use in the I'nited MILE. A measure of length in common use ^tatf- " V' it^'";itn j" t^, '•^if^ to make in Great Britain and the United States and their legislators entirely independent of the transporta- colonics. The name is also in use on the Conti- *""! companies which carried them to and from nent of Europe to designate generally a much t'"-"- respective capitals. Railroad companies, larger measure of length, although the official however, have always freely granted passes to measure is now generally the kilometer. It Senators and Representatives, and this has led to is derived from the Roman miUiare. which con- *« enactment by several State legislatures of taincd 1000 paces imiUe passuum) of 5 laws forbidding any public otiicial from .accepting Roman feet each, the pace heing the length gratuitous passage from public earners, of the step made by one foot. The Roman MILELLl, me-lel'h'. noMENTCO (1841 — ). foot being between 11.62 and 11.05 English An Italian poet, born at Catanzaro. in Calabria, inches, the Roman mile was thus less than the He was educated for the priesthood, but did not
